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Title: A History of Aeronautics
Author: Marsh, W. Lockwood (William Lockwood), Vivian, Evelyn Charles
Language: English
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A HISTORY OF AERONAUTICS
[Illustration: Trial of full-size Langley Aerodrome, 8th December, 1903.
Langley Memoir on Mechanical Flight, Smithsonian Institution,
Washington.
_Frontispiece._
]
A
History of Aeronautics
_by_
E. CHARLES VIVIAN
WITH A SECTION ON PROGRESS IN
AEROPLANE DESIGN
_by_
LIEUT.-COL. W. LOCKWOOD MARSH, O.B.E.
[Illustration]
NEW YORK
HARCOURT, BRACE AND COMPANY
1921
_To_
MY WITNESS
OCT. 21ST 1919
V.
FOREWORD
Although successful heavier-than-air flight is less than two decades
old, and successful dirigible propulsion antedates it by a very
short period, the mass of experiment and accomplishment renders any
one-volume history of the subject a matter of selection. In addition to
the restrictions imposed by space limits, the material for compilation
is fragmentary, and, in many cases, scattered through periodical and
other publications. Hitherto, there has been no attempt at furnishing a
detailed account of how the aeroplane and the dirigible of to-day came
to being, but each author who has treated the subject has devoted his
attention to some special phase or section. The principal exception
to this rule--Hildebrandt--wrote in 1906, and a good many of his
statements are inaccurate, especially with regard to heavier-than-air
experiment.
Such statements as are made in this work are, where possible, given
with acknowledgment to the authorities on which they rest. Further
acknowledgment is due to Lieut.-Col. Lockwood Marsh, not only for
the section on aeroplane development which he has contributed to the
work, but also for his kindly assistance and advice in connection with
the section on aerostation. The author’s thanks are also due to the
Royal Aeronautical Society for free access to its valuable library of
aeronautical literature, and to Mr A. Vincent Clarke for permission to
make use of his notes on the development of the aero engine.
In this work is no claim to originality--it has been a matter mainly of
compilation, and some stories, notably those of the Wright Brothers and
of Santos Dumont, are better told in the words of the men themselves
than any third party could tell them. The author claims, however, that
this is the first attempt at recording the facts of development and
stating, as fully as is possible in the compass of a single volume, how
flight and aerostation have evolved. The time for a critical history of
the subject is not yet.
In the matter of illustrations, it has been found very difficult to
secure suitable material. Even the official series of photographs
of aeroplanes in the war period is curiously incomplete, and the
methods of censorship during that period prevented any complete series
being privately collected. Omissions in this respect will probably
be remedied in future editions of the work, as fresh material is
constantly being located.
E. C. V.
_October, 1920._
CONTENTS
PART I--THE EVOLUTION OF THE AEROPLANE
CHAP. PAGE
I. THE PERIOD OF LEGEND 3
II. EARLY EXPERIMENTS 15
III. SIR GEORGE CAYLEY--THOMAS WALKER 43
IV. THE MIDDLE NINETEENTH CENTURY 56
V. WENHAM, LE BRIS, AND SOME OTHERS 71
VI. THE AGE OF THE GIANTS 83
VII. LILIENTHAL AND PILCHER 95
VIII. AMERICAN GLIDING EXPERIMENTS 107
IX. NOT PROVEN 121
X. SAMUEL PIERPOINT LANGLEY 133
XI. THE WRIGHT BROTHERS 145
XII. THE FIRST YEARS OF CONQUEST 176
XIII. FIRST FLIERS IN ENGLAND 188
XIV. RHEIMS, AND AFTER 199
XV. THE CHANNEL CROSSING 211
XVI. LONDON TO MANCHESTER 217
XVII. A SUMMARY--TO 1911 221
XVIII. A SUMMARY--TO 1914 233
XIX. THE WAR PERIOD--I 246
XX. THE WAR PERIOD--II 259
XXI. RECONSTRUCTION 264
XXII. 1919–1920 270
PART II--1903–1920: PROGRESS IN DESIGN
I. THE BEGINNINGS 277
II. MULTIPLICITY OF IDEAS 289
III. PROGRESS ON STANDARDISED LINES 296
IV. THE WAR PERIOD 306
PART III--AEROSTATICS
I. BEGINNINGS 317
II. THE FIRST DIRIGIBLES 331
III. SANTOS-DUMONT 342
IV. THE MILITARY DIRIGIBLE 348
V. BRITISH AIRSHIP DESIGN 359
VI. THE AIRSHIP COMMERCIALLY 372
VII. KITE BALLOONS 376
PART IV--ENGINE DEVELOPMENT
I. THE VERTICAL TYPE 383
II. THE VEE TYPE 404
III. THE RADIAL TYPE 417
IV. THE ROTARY TYPE 428
V. THE HORIZONTALLY-OPPOSED ENGINE 440
VI. THE TWO-STROKE CYCLE ENGINE 447
VII. ENGINES OF THE WAR PERIOD 458
APPENDICES 469
A SHORT BIBLIOGRAPHY OF AERONAUTICS 504
PART I
THE EVOLUTION OF THE AEROPLANE
I
THE PERIOD OF LEGEND
The blending of fact and fancy which men call legend reached its
fullest and richest expression in the golden age of Greece, and thus
it is to Greek mythology that one must turn for the best form of
any legend which foreshadows history. Yet the prevalence of legends
regarding flight, existing in the records of practically every race,
shows that this form of transit was a dream of many peoples--man always
wanted to fly, and imagined means of flight.
In this age of steel, a very great part of the inventive genius of man
has gone into devices intended to facilitate transport, both of men and
goods, and the growth of civilisation is in reality the facilitation of
transit, improvement of the means of communication. He was a genius who
first hoisted a sail on a boat and saved the labour of rowing; equally,
he who first harnessed ox or dog or horse to a wheeled vehicle was a
genius--and these looked up, as men have looked up from the earliest
days of all, seeing that the birds had solved the problem of transit
far more completely than themselves. So it must have appeared, and
there is no age in history in which some dreamers have not dreamed
of the conquest of the air; if the caveman had left records, these
would without doubt have showed that he, too, dreamed this dream. His
main aim, probably, was self-preservation; when the dinosaur looked
round the corner, the prehistoric bird got out of the way in his usual
manner, and prehistoric man--such of him as succeeded in getting out
of the way after his fashion--naturally envied the bird, and concluded
that as lord of creation in a doubtful sort of way he ought to have
equal facilities. He may have tried, like Simon the Magician, and other
early experimenters, to improvise those facilities; assuming that he
did, there is the groundwork of much of the older legend with regard to
men who flew, since, when history began, legends would be fashioned out
of attempts and even the desire to fly, these being compounded of some
small ingredient of truth and much exaggeration and addition.
In a study of the first beginnings of the art, it is worth while to
mention even the earliest of the legends and traditions, for they
show the trend of men’s minds and the constancy of this dream that
has become reality in the twentieth century. In one of the oldest
records of the world, the Indian classic _Mahabarata_, it is stated
that ‘Krishna’s enemies sought the aid of the demons, who built an
aerial chariot with sides of iron and clad with wings. The chariot was
driven through the sky till it stood over Dwarakha, where Krishna’s
followers dwelt, and from there it hurled down upon the city missiles
that destroyed everything on which they fell.’ Here is pure fable, not
legend, but still a curious forecast of twentieth century bombs from a
rigid dirigible. It is to be noted in this case, as in many, that the
power to fly was an attribute of evil, not of good--it was the demons
who built the chariot, even as at Friedrichshavn. Mediæval legend,
in nearly every case, attributes flight to the aid of evil powers,
and incites well-disposed people to stick to the solid earth--though,
curiously enough, the pioneers of mediæval times were very largely of
priestly type, as witness the monk of Malmesbury.
The legends of the dawn of history, however, distribute the power of
flight with less of prejudice. Egyptian sculpture gives the figure
of winged men; the British Museum has made the winged Assyrian bulls
familiar to many, and both the cuneiform records of Assyria and the
hieroglyphs of Egypt record flights that in reality were never made.
The desire fathered the story then, and until Clement Ader either
hopped with his _Avion_, as is persisted by his critics, or flew, as is
claimed by his friends.
While the origin of many legends is questionable, that of others is
easy enough to trace, though not to prove. Among the credulous the
significance of the name of a people of Asia Minor, the Capnobates,
‘those who travel by smoke,’ gave rise to the assertion that Mongolfier
was not first in the field--or rather in the air--since surely this
people must have been responsible for the first hot-air balloons. Far
less questionable is the legend of Icarus, for here it is possible
to trace a foundation of fact in the story. Such a tribe as Dædalus
governed could have had hardly any knowledge of the rudiments of
science, and even their ruler, seeing how easy it is for birds to
sustain themselves in the air, might be excused for believing that he,
if he fashioned wings for himself, could use them. In that belief, let
it be assumed, Dædalus made his wings; the boy, Icarus, learning that
his father had determined on an attempt at flight, secured the wings
and fastened them to his own shoulders. A cliff seemed the likeliest
place for a ‘take-off,’ and Icarus leaped from the cliff edge only to
find that the possession of wings was not enough to assure flight to a
human being. The sea that to this day bears his name witnesses that he
made the attempt and perished by it.
In this is assumed the bald story, from which might grow the legend of
a wise king who ruled a peaceful people--‘judged, sitting in the sun,’
as Browning has it, and fashioned for himself wings with which he flew
over the sea and where he would, until the prince, Icarus, desired
to emulate him. Icarus, fastening the wings to his shoulders with
wax, was so imprudent as to fly too near the sun, when the wax melted
and he fell, to lie mourned of water-nymphs on the shores of waters
thenceforth Icarian. Between what we have assumed to be the base of
fact, and the legend which has been invested with such poetic grace in
Greek story, there is no more than a century or so of re-telling might
give to any event among a people so simple and yet so given to imagery.
We may set aside as pure fable the stories of the winged horse of
Perseus, and the flights of Hermes as messenger of the gods. With
them may be placed the story of Empedocles, who failed to take Etna
seriously enough, and found himself caught by an eruption while within
the crater, so that, flying to safety in some hurry, he left behind
but one sandal to attest that he had sought refuge in space--in all
probability, if he escaped at all, he flew, but not in the sense that
the aeronaut understands it. But, bearing in mind the many men who
tried to fly in historic times, the legend of Icarus and Dædalus, in
spite of the impossible form in which it is presented, may rank with
the story of the Saracen of Constantinople, or with that of Simon the
Magician. A simple folk would naturally idealise the man and magnify
his exploit, as they magnified the deeds of some strong man to make
the legends of Hercules, and there, full-grown from a mere legend, is
the first record of a pioneer of flying. Such a theory is not nearly
so fantastic as that which makes the Capnobates, on the strength of
their name, the inventors of hot-air balloons. However it may be, both
in story and in picture, Icarus and his less conspicuous father have
inspired the Caucasian mind, and the world is the richer for them.
Of the unsupported myths--unsupported, that is, by even a shadow of
probability--there is no end. Although Latin legend approaches nearer
to fact than the Greek in some cases, in others it shows a disregard
for possibilities which renders it of far less account. Thus Diodorus
of Sicily relates that one Abaris travelled round the world on an arrow
of gold, and Cassiodorus and Glycas and their like told of mechanical
birds that flew and sang and even laid eggs. More credible is the story
of Aulus Gellius, who in his _Attic Nights_ tells how Archytas, four
centuries prior to the opening of the Christian era, made a wooden
pigeon that actually flew by means of a mechanism of balancing weights
and the breath of a mysterious spirit hidden within it. There may yet
arise one credulous enough to state that the mysterious spirit was
precursor of the internal combustion engine, but, however that may
be, the pigeon of Archytas almost certainly existed, and perhaps it
actually glided or flew for short distances--or else Aulus Gellius was
an utter liar, like Cassiodorus and his fellows. In far later times a
certain John Muller, better known as Regiomontanus, is stated to have
made an artificial eagle which accompanied Charles V. on his entry
to and exit from Nuremberg, flying above the royal procession. But,
since Muller died in 1436 and Charles was born in 1500, Muller may be
ruled out from among the pioneers of mechanical flight, and it may be
concluded that the historian of this event got slightly mixed in his
dates.
Thus far, we have but indicated how one may draw from the richest
stores from which the Aryan mind draws inspiration, the Greek and Latin
mythologies and poetic adaptations of history. The existing legends of
flight, however, are not thus to be localised, for with two possible
exceptions they belong to all the world and to every civilisation,
however primitive. The two exceptions are the Aztec and the Chinese;
regarding the first of these, the Spanish _conquistadores_ destroyed
such civilisation as existed in Tenochtitlan so thoroughly that, if
legend of flight was among the Aztec records, it went with the rest; as
to the Chinese, it is more than passing strange that they, who claim to
have known and done everything while the first of history was shaping,
even to antedating the discovery of gunpowder that was _not_ made by
Roger Bacon, have not yet set up a claim to successful handling of a
monoplane some four thousand years ago, or at least to the patrol of
the Gulf of Korea and the Mongolian frontier by a forerunner of the
‘blimp.’
The Inca civilisation of Peru yields up a myth akin to that of Icarus,
which tells how the chieftain Ayar Utso grew wings and visited the
sun--it was from the sun, too, that the founders of the Peruvian Inca
dynasty, Manco Capac and his wife Mama Huella Capac, flew to earth near
Lake Titicaca, to make the only successful experiment in pure tyranny
that the world has ever witnessed. Teutonic legend gives forth Wieland
the Smith, who made himself a dress with wings and, clad in it, rose
and descended against the wind and in spite of it. Indian mythology, in
addition to the story of the demons and their rigid dirigible, already
quoted, gives the story of Hanouam, who fitted himself with wings by
means of which he sailed in the air and, according to his desire,
landed in the sacred Lauka. Bladud, the ninth king of Britain, is said
to have crowned his feats of wizardry by making himself wings and
attempting to fly--but the effort cost him a broken neck. Bladud may
have been as mythic as Uther, and again he may have been a very early
pioneer. The Finnish epic, ‘Kalevala,’ tells how Ilmarinen the Smith
‘forged an eagle of fire,’ with ‘boat’s walls between the wings,’ after
which he ‘sat down on the bird’s back and bones,’ and flew.
Pure myths, these, telling how the desire to fly was characteristic of
every age and every people, and how, from time to time, there arose
an experimenter bolder than his fellows, who made some attempt to
translate desire into achievement. And the spirit that animated these
pioneers, in a time when things new were accounted things accursed,
for the most part, has found expression in this present century in the
utter daring and disregard of both danger and pain that stamps the
flying man, a type of humanity differing in spirit from his earth-bound
fellows as fully as the soldier differs from the priest.
Throughout mediæval times, records attest that here and there some
man believed in and attempted flight, and at the same time it is clear
that such were regarded as in league with the powers of evil. There is
the half-legend, half-history of Simon the Magician, who, in the third
year of the reign of Nero announced that he would raise himself in
the air, in order to assert his superiority over St Paul. The legend
states that by the aid of certain demons whom he had prevailed on to
assist him, he actually lifted himself in the air--but St Paul prayed
him down again. He slipped through the claws of the demons and fell
headlong on the Forum at Rome, breaking his neck. The ‘demons’ may have
been some primitive form of hot-air balloon, or a glider with which
the magician attempted to rise into the wind; more probably, however,
Simon threatened to ascend and made the attempt with apparatus as
unsuitable as Bladud’s wings, paying the inevitable penalty. Another
version of the story gives St Peter instead of St Paul as the one whose
prayers foiled Simon--apart from the identity of the apostle, the two
accounts are similar, and both define the attitude of the age toward
investigation and experiment in things untried.
Another and later circumstantial story, with similar evidence of some
fact behind it, is that of the Saracen of Constantinople, who, in the
reign of the Emperor Comnenus--some little time before Norman William
made Saxon Harold swear away his crown on the bones of the saints at
Rouen--attempted to fly round the hippodrome at Constantinople, having
Comnenus among the great throng who gathered to witness the feat.
The Saracen chose for his starting-point a tower in the midst of the
hippodrome, and on the top of the tower he stood, clad in a long
white robe which was stiffened with rods so as to spread and catch the
breeze, waiting for a favourable wind to strike on him. The wind was so
long in coming that the spectators grew impatient. ‘Fly, O Saracen!’
they called to him. ‘Do not keep us waiting so long while you try the
wind!’ Comnenus, who had present with him the Sultan of the Turks, gave
it as his opinion that the experiment was both dangerous and vain, and,
possibly in an attempt to controvert such statement, the Saracen leaned
into the wind and ‘rose like a bird’ at the outset. But the record of
Cousin, who tells the story in his _Histoire de Constantinople_, states
that ‘the weight of his body having more power to drag him down than
his artificial wings had to sustain him, he broke his bones, and his
evil plight was such that he did not long survive.’
Obviously, the Saracen was anticipating Lilienthal and his gliders
by some centuries; like Simon, a genuine experimenter--both legends
bear the impress of fact supporting them. Contemporary with him, and
belonging to the history rather than the legends of flight, was Oliver,
the monk of Malmesbury, who in the year 1065 made himself wings after
the pattern of those supposed to have been used by Dædalus, attaching
them to his hands and feet and attempting to fly with them. Twysden, in
his _Historiæ Anglicanæ Scriptores X_, sets forth the story of Oliver,
who chose a high tower as his starting-point, and launched himself in
the air. As a matter of course, he fell, permanently injuring himself,
and died some time later.
After these, a gap of centuries, filled in by impossible stories of
magical flight by witches, wizards, and the like--imagination was
fertile in the dark ages, but the ban of the church was on all attempt
at scientific development, especially in such a matter as the conquest
of the air. Yet there were observers of nature who argued that since
birds could raise themselves by flapping their wings, man had only
to make suitable wings, flap them, and he too would fly. As early as
the thirteenth century Roger Bacon, the scientific friar of unbounded
inquisitiveness and not a little real genius, announced that there
could be made ‘some flying instrument, so that a man sitting in the
middle and turning some mechanism may put in motion some artificial
wings which may beat the air like a bird flying.’ But being a cautious
man, with a natural dislike for being burnt at the stake as a
necromancer through having put forward such a dangerous theory, Roger
added, ‘not that I ever knew a man who had such an instrument, but I
am particularly acquainted with the man who contrived one.’ This might
have been a lame defence if Roger had been brought to trial as addicted
to black arts; he seems to have trusted to the inadmissibility of
hearsay evidence.
Some four centuries later there was published a book entitled _Perugia
Augusta_, written by one C. Crispolti of Perugia--the date of the work
in question is 1648. In it is recorded that ‘one day, towards the close
of the fifteenth century, whilst many of the principal gentry had come
to Perugia to honour the wedding of Giovanni Paolo Baglioni, and some
lancers were riding down the street by his palace, Giovanni Baptisti
Danti unexpectedly and by means of a contrivance of wings that he
had constructed proportionate to the size of his body took off from
the top of a tower near by, and with a horrible hissing sound flew
successfully across the great Piazza, which was densely crowded. But
(oh, horror of an unexpected accident!) he had scarcely flown three
hundred paces on his way to a certain point when the mainstay of the
left wing gave way, and, being unable to support himself with the right
alone, he fell on a roof and was injured in consequence. Those who
saw not only this flight, but also the wonderful construction of the
framework of the wings, said--and tradition bears them out--that he
several times flew over the waters of Lake Thrasimene to learn how he
might gradually come to earth. But, notwithstanding his great genius,
he never succeeded.’
This reads circumstantially enough, but it may be borne in mind that
the date of writing is more than half a century later than the time of
the alleged achievement--the story had had time to round itself out.
Danti, however, is mentioned by a number of writers, one of whom states
that the failure of his experiment was due to the prayers of some
individual of a conservative turn of mind, who prayed so vigorously
that Danti fell appropriately enough on a church and injured himself
to such an extent as to put an end to his flying career. That Danti
experimented, there is little doubt, in view of the volume of evidence
on the point, but the darkness of the Middle Ages hides the real truth
as to the results of his experiments. If he had actually flown over
Thrasimene, as alleged, then in all probability both Napoleon and
Wellington would have had air scouts at Waterloo.
Danti’s story may be taken as fact or left as fable, and with it the
period of legend or vague statement may be said to end--the rest
is history, both of genuine experimenters and of charlatans. Such
instances of legend as are given here are not a tithe of the whole, but
there is sufficient in the actual history of flight to bar out more
than this brief mention of the legends, which, on the whole, go farther
to prove man’s desire to fly than his study and endeavour to solve the
problems of the air.
II
EARLY EXPERIMENTS
So far, the stories of the development of flight are either legendary
or of more or less doubtful authenticity, even including that of Danti,
who, although a man of remarkable attainments in more directions
than that of attempted flight, suffers--so far as reputation is
concerned--from the inexactitudes of his chroniclers; he may have
soared over Thrasimene, as stated, or a mere hop with an ineffectual
glider may have grown with the years to a legend of gliding flight. So
far, too, there is no evidence of the study that the conquest of the
air demanded; such men as made experiments either launched themselves
in the air from some height with made-up wings or other apparatus,
and paid the penalty, or else constructed some form of machine which
would not leave the earth, and then gave up. Each man followed his
own way, and there was no attempt--without the printing press and the
dissemination of knowledge there was little possibility of attempt--on
the part of any one to benefit by the failures of others.
Legend and doubtful history carries up to the fifteenth century, and
then came Leonardo da Vinci, first student of flight whose work endures
to the present day. The world knows da Vinci as artist; his age knew
him as architect, engineer, artist, and scientist in an age when
science was a single study, comprising all knowledge from mathematics
to medicine. He was, of course, in league with the devil, for in no
other way could his range of knowledge and observation be explained
by his contemporaries; he left a _Treatise on the Flight of Birds_
in which are statements and deductions that had to be rediscovered
when the _Treatise_ had been forgotten--da Vinci anticipated modern
knowledge as Plato anticipated modern thought, and blazed the first
broad trail toward flight.
One Cuperus, who wrote a _Treatise on the Excellence of Man_, asserted
that da Vinci translated his theories into practice, and actually flew,
but the statement is unsupported. That he made models, especially on
the helicopter principle, is past question; these were made of paper
and wire, and actuated by springs of steel wire, which caused them to
lift themselves in the air. It is, however, in the theories which he
put forward that da Vinci’s investigations are of greatest interest;
these prove him a patient as well as a keen student of the principles
of flight, and show that his manifold activities did not prevent him
from devoting some lengthy periods to observations of bird flight.
‘A bird,’ he says in his _Treatise_, ‘is an instrument working
according to mathematical law, which instrument it is within the
capacity of man to reproduce with all its movements, but not with
a corresponding degree of strength, though it is deficient only in
power of maintaining equilibrium. We may say, therefore, that such an
instrument constructed by man is lacking in nothing except the life of
the bird, and this life must needs be supplied from that of man. The
life which resides in the bird’s members will, without doubt, better
conform to their needs than will that of a man which is separated
from them, and especially in the almost imperceptible movements which
produce equilibrium. But since we see that the bird is equipped for
many apparent varieties of movement, we are able from this experience
to deduce that the most rudimentary of these movements will be capable
of being comprehended by man’s understanding, and that he will to
a great extent be able to provide against the destruction of that
instrument of which he himself has become the living principle and the
propeller.’
In this is the definite belief of da Vinci that man is capable of
flight, together with a far more definite statement of the principles
by which flight is to be achieved than any which had preceded it--and
for that matter, than many that have succeeded it. Two further extracts
from his work will show the exactness of his observations:--
‘When a bird which is in equilibrium throws the centre of resistance of
the wings behind the centre of gravity, then such a bird will descend
with its head downward. This bird which finds itself in equilibrium
shall have the centre of resistance of the wings more forward than the
bird’s centre of gravity; then such a bird will fall with its tail
turned toward the earth.’
And again: ‘A man, when flying, shall be free from the waist up, that
he may be able to keep himself in equilibrium as he does in a boat, so
that the centre of his gravity and of the instrument may set itself in
equilibrium and change when necessity requires it to the changing of
the centre of its resistance.’
Here, in this last quotation, are the first beginnings of the inherent
stability which proved so great an advance in design, in this
twentieth century. But the extracts given do not begin to exhaust the
range of da Vinci’s observations and deductions. With regard to bird
flight, he observed that so long as a bird keeps its wings outspread
it cannot fall directly to earth, but must glide down at an angle
to alight--a small thing, now that the principle of the plane in
opposition to the air is generally grasped, but da Vinci had to find
it out. From observation he gathered how a bird checks its own speed
by opposing tail and wing surface to the direction of flight, and
thus alights at the proper ‘landing speed.’ He proved the existence
of upward air currents by noting how a bird takes off from level
earth with wings outstretched and motionless, and, in order to get an
efficient substitute for the natural wing, he recommended that there
be used something similar to the membrane of the wing of a bat--from
this to the doped fabric of an aeroplane wing is but a small step, for
both are equally impervious to air. Again, da Vinci recommended that
experiments in flight be conducted at a good height from the ground,
since, if equilibrium be lost through any cause, the height gives time
to regain it. This recommendation, by the way, received ample support
in the training areas of war pilots.
Man’s muscles, said da Vinci, are fully sufficient to enable him to
fly, for the larger birds, he noted, employ but a small part of their
strength in keeping themselves afloat in the air--by this theory he
attempted to encourage experiment, just as, when his time came, Borelli
reached the opposite conclusion and discouraged it. That Borelli was
right--so far--and da Vinci wrong, detracts not at all from the repute
of the earlier investigator, who had but the resources of his age to
support investigations conducted in the spirit of ages after.
His chief practical contributions to the science of flight--apart
from numerous drawings which have still a value--are the helicopter
or lifting screw, and the parachute. The former, as already noted,
he made and proved effective in model form, and the principle which
he demonstrated is that of the helicopter of to-day, on which sundry
experimenters work spasmodically, in spite of the success of the plane
with its driving propeller. As to the parachute, the idea was doubtless
inspired by observation of the effect a bird produced by pressure of
its wings against the direction of flight.
Da Vinci’s conclusions, and his experiments, were forgotten easily by
most of his contemporaries; his _Treatise_ lay forgotten for nearly
four centuries, overshadowed, mayhap, by his other work. There was,
however, a certain Paolo Guidotti of Lucca, who lived in the latter
half of the sixteenth century, and who attempted to carry da Vinci’s
theories--one of them, at least, into practice. For this Guidotti, who
was by profession an artist and by inclination an investigator, made
for himself wings, of which the framework was of whalebone; these he
covered with feathers, and with them made a number of gliding flights,
attaining considerable proficiency. He is said in the end to have made
a flight of about four hundred yards, but this attempt at solving the
problem ended on a house roof, where Guidotti broke his thigh bone.
After that, apparently, he gave up the idea of flight, and went back to
painting.
One other, a Venetian architect named Veranzio, studied da Vinci’s
theory of the parachute, and found it correct, if contemporary records
and even pictorial presentment are correct. Da Vinci showed his
conception of a parachute as a sort of inverted square bag; Veranzio
modified this to a ‘sort of square sail extended by four rods of equal
size and having four cords attached at the corners,’ by means of which
‘a man could without danger throw himself from the top of a tower or
any high place. For though at the moment there may be no wind, yet the
effort of his falling will carry up the wind, which the sail will hold,
by which means he does not fall suddenly but descends little by little.
The size of the sail should be measured to the man.’ By this last,
evidently, Veranzio intended to convey that the sheet must be of such
content as would enclose sufficient air to support the weight of the
parachutist.
Veranzio made his experiments about 1617–1618, but, naturally, they
carried him no farther than the mere descent to earth, and since a
descent is merely a descent, it is to be conjectured that he soon got
tired of dropping from high roofs, and took to designing architecture
instead of putting it to such a use. With the end of his experiments
the work of da Vinci in relation to flying became neglected for nearly
four centuries.
Apart from these two experimenters, there is little to record in the
matter either of experiment or study until the seventeenth century.
Francis Bacon, it is true, wrote about flying in his _Sylva Sylvarum_,
and mentioned the subject in the _New Atlantis_, but, except for
the insight that he showed even in superficial mention of any
specific subject, he does not appear to have made attempt at serious
investigation. ‘Spreading of Feathers, thin and close and in great
breadth will likewise bear up a great Weight,’ says Francis, ‘being
even laid without Tilting upon the sides.’ But a lesser genius could
have told as much, even in that age, and though the great Sir Francis
is sometimes adduced as one of the early students of the problems of
flight, his writings will not sustain the reputation.
The seventeenth century, however, gives us three names, those of
Borelli, Lana, and Robert Hooke, all of which take definite place in
the history of flight. Borelli ranks as one of the great figures in
the study of aeronautical problems, in spite of erroneous deductions
through which he arrived at a purely negative conclusion with regard to
the possibility of human flight.
Borelli was a versatile genius. Born in 1608, he was practically
contemporary with Francesco Lana, and there is evidence that he either
knew or was in correspondence with many prominent members of the Royal
Society of Great Britain, more especially with John Collins, Dr Wallis,
and Henry Oldenburgh, the then Secretary of the Society. He was author
of a long list of scientific essays, two of which only are responsible
for his fame, viz., _Theorice Medicæarum Planetarum_, published in
Florence, and the better known posthumous _De Motu Animalium_. The
first of these two is an astronomical study in which Borelli gives
evidence of an instinctive knowledge of gravitation, though no definite
expression is given of this. The second work, _De Motu Animalium_,
deals with the mechanical action of the limbs of birds and animals
and with a theory of the action of the internal organs. A section of
the first part of this work, called _De Volatu_, is a study of bird
flight; it is quite independent of Da Vinci’s earlier work, which had
been forgotten and remained unnoticed until near on the beginning of
practical flight.
Marey, in his work, _La Machine Animale_, credits Borelli with the
first correct idea of the mechanism of flight. He says: ‘Therefore we
must be allowed to render to the genius of Borelli the justice which is
due to him, and only claim for ourselves the merit of having furnished
the experimental demonstration of a truth already suspected.’ In fact,
all subsequent studies on this subject concur in making Borelli the
first investigator who illustrated the purely mechanical theory of the
action of a bird’s wings.
Borelli’s study is divided into a series of propositions in which he
traces the principles of flight, and the mechanical actions of the
wings of birds. The most interesting of these are the propositions
in which he sets forth the method in which birds move their wings
during flight and the manner in which the air offers resistance to the
stroke of the wing. With regard to the first of these two points he
says: ‘When birds in repose rest on the earth their wings are folded
up close against their flanks, but when wishing to start on their
flight they first bend their legs and leap into the air. Whereupon
the joints of their wings are straightened out to form a straight
line at right angles to the lateral surface of the breast, so that
the two wings, outstretched, are placed, as it were, like the arms
of a cross to the body of the bird. Next, since the wings with their
feathers attached form almost a plane surface, they are raised slightly
above the horizontal, and with a most quick impulse beat down in a
direction almost perpendicular to the wing-plane, upon the underlying
air; and to so intense a beat the air, notwithstanding it to be
fluid, offers resistance, partly by reason of its natural inertia,
which seeks to retain it at rest, and partly because the particles
of the air, compressed by the swiftness of the stroke, resist this
compression by their elasticity, just like the hard ground. Hence
the whole mass of the bird rebounds, making a fresh leap through the
air; whence it follows that flight is simply a motion composed of
successive leaps accomplished through the air. And I remark that a
wing can easily beat the air in a direction almost perpendicular to
its plane surface, although only a single one of the corners of the
humerus bone is attached to the scapula, the whole extent of its base
remaining free and loose, while the greater transverse feathers are
joined to the lateral skin of the thorax. Nevertheless the wing can
easily revolve about its base like unto a fan. Nor are there lacking
tendon ligaments which restrain the feathers and prevent them from
opening farther, in the same fashion that sheets hold in the sails of
ships. No less admirable is nature’s cunning in unfolding and folding
the wings upwards, for she folds them not laterally, but by moving
upwards edgewise the osseous parts wherein the roots of the feathers
are inserted; for thus, without encountering the air’s resistance the
upward motion of the wing surface is made as with a sword, hence they
can be uplifted with but small force. But thereafter when the wings
are twisted by being drawn transversely and by the resistance of the
air, they are flattened as has been declared and will be made manifest
hereafter.’
Then with reference to the resistance to the air of the wings he
explains: ‘The air when struck offers resistance by its elastic virtue
through which the particles of the air compressed by the wing-beat
strive to expand again. Through these two causes of resistance the
downward beat of the wing is not only opposed, but even caused to
recoil with a reflex movement; and these two causes of resistance
ever increase the more the down stroke of the wing is maintained and
accelerated. On the other hand, the impulse of the wing is continuously
diminished and weakened by the growing resistance. Hereby the force of
the wing and the resistance become balanced; so that, manifestly, the
air is beaten by the wing with the same force as the resistance to the
stroke.’
He concerns himself also with the most difficult problem that confronts
the flying man of to-day, namely, landing effectively, and his remarks
on this subject would be instructive even to an air pilot of these
days: ‘Now the ways and means by which the speed is slackened at the
end of a flight are these. The bird spreads its wings and tail so that
their concave surfaces are perpendicular to the direction of motion; in
this way, the spreading feathers, like a ship’s sail, strike against
the still air, check the speed, and so that most of the impetus may be
stopped, the wings are flapped quickly and strongly forward, inducing a
contrary motion, so that the bird absolutely or very nearly stops.’
At the end of his study Borelli came to a conclusion which militated
greatly against experiment with any heavier-than-air apparatus, until
well on into the nineteenth century, for having gone thoroughly into
the subject of bird flight he states distinctly in his last proposition
on the subject that ‘It is impossible that men should be able to fly
craftily by their own strength.’ This statement, of course, remains
true up to the present day, for no man has yet devised the means by
which he can raise himself in the air and maintain himself there by
mere muscular effort.
From the time of Borelli up to the development of the steam engine it
may be said that flight by means of any heavier-than-air apparatus was
generally regarded as impossible, and apart from certain deductions
which a little experiment would have shown to be doomed to failure,
this method of flight was not followed up. It is not to be wondered
at, when Borelli’s exaggerated estimate of the strength expended by
birds in proportion to their weight is borne in mind; he alleged
that the motive force in birds’ wings is 10,000 times greater than
the resistance of their weight, and with regard to human flight he
remarks:--
‘When, therefore, it is asked whether men may be able to fly by their
own strength, it must be seen whether the motive power of the pectoral
muscles (the strength of which is indicated and measured by their size)
is proportionately great, as it is evident that it must exceed the
resistance of the weight of the whole human body 10,000 times, together
with the weight of enormous wings which should be attached to the arms.
And it is clear that the motive power of the pectoral muscles in men
is much less than is necessary for flight, for in birds the bulk and
weight of the muscles for flapping the wings are not less than a sixth
part of the entire weight of the body. Therefore, it would be necessary
that the pectoral muscles of a man should weigh more than a sixth
part of the entire weight of his body; so also the arms, by flapping
with the wings attached, should be able to exert a power 10,000 times
greater than the weight of the human body itself. But they are far
below such excess, for the aforesaid pectoral muscles do not equal
a hundredth part of the entire weight of a man. Wherefore either the
strength of the muscles ought to be increased or the weight of the
human body must be decreased, so that the same proportion obtains in
it as exists in birds. Hence it is deducted that the Icarian invention
is entirely mythical because impossible, for it is not possible either
to increase a man’s pectoral muscles or to diminish the weight of the
human body; and whatever apparatus is used, although it is possible to
increase the momentum, the velocity or the power employed can never
equal the resistance; and therefore wing flapping by the contraction of
muscles cannot give out enough power to carry up the heavy body of a
man.’
It may be said that practically all the conclusions which Borelli
reached in his study were negative. Although contemporary with Lana,
he perceived the one factor which rendered Lana’s project for flight
by means of vacuum globes an impossibility--he saw that no globe
could be constructed sufficiently light for flight, and at the same
time sufficiently strong to withstand the pressure of the outside
atmosphere. He does not appear to have made any experiments in flying
on his own account, having, as he asserts most definitely, no faith in
any invention designed to lift man from the surface of the earth. But
his work, from which only the foregoing short quotations can be given,
is, nevertheless, of indisputable value, for he settled the mechanics
of bird flight, and paved the way for those later investigators who
had, first, the steam engine, and later the internal combustion
engine--two factors in mechanical flight which would have seemed as
impossible to Borelli as would wireless telegraphy to a student of
Napoleonic times. On such foundations as his age afforded Borelli built
solidly and well, so that he ranks as one of the greatest--if not
actually the greatest--of the investigators into this subject before
the age of steam.
The conclusion, that ‘the motive force in birds’ wings is apparently
ten thousand times greater than the resistance of their weight,’
is erroneous, of course, but study of the translation from which
the foregoing excerpt is taken will show that the error detracts
very little from the value of the work itself. Borelli sets out
very definitely the mechanism of flight, in such fashion that he
who runs may read. His reference to ‘the use of a large vessel,’
etc., concerns the suggestion made by Francesco Lana, who antedated
Borelli’s publication of _De Motu Animalium_ by some ten years with his
suggestion for an ‘aerial ship,’ as he called it. Lana’s mind shows, as
regards flight, a more imaginative twist; Borelli dived down into first
causes, and reached mathematical conclusions; Lana conceived a theory
and upheld it--theoretically, since the manner of his life precluded
experiment.
Francesco Lana, son of a noble family, was born in 1631; in 1647 he was
received as a novice into the Society of Jesus at Rome, and remained
a pious member of the Jesuit society until the end of his life. He
was greatly handicapped in his scientific investigations by the vows
of poverty which the rules of the Order imposed on him. He was more
scientist than priest all his life; for two years he held the post of
Professor of Mathematics at Ferrara, and up to the time of his death,
in 1687, he spent by far the greater part of his time in scientific
research. He had the dubious advantage of living in an age when one
man could cover the whole range of science, and this he seems to have
done very thoroughly. There survives an immense work of his entitled,
_Magisterium Naturæ et Artis_, which embraces the whole field of
scientific knowledge as that was developed in the period in which Lana
lived. In an earlier work of his, published in Brescia in 1670, appears
his famous treatise on the aerial ship, a problem which Lana worked out
with thoroughness. He was unable to make practical experiments, and
thus failed to perceive the one insuperable drawback to his project--of
which more anon.
Only extracts from the translation of Lana’s work can be given here,
but sufficient can be given to show fully the means by which he
designed to achieve the conquest of the air. He begins by mention of
the celebrated pigeon of Archytas the Philosopher, and advances one
or two theories with regard to the way in which this mechanical bird
was constructed, and then he recites, apparently with full belief in
it, the fable of _Regiomontanus_ and the eagle that he is said to have
constructed to accompany Charles V. on his entry into Nuremberg. In
fact, Lana starts his work with a study of the pioneers of mechanical
flying up to his own time, and then outlines his own devices for the
construction of mechanical birds before proceeding to detail the
construction of the aerial ship. Concerning primary experiments for
this he says:--
‘I will, first of all, presuppose that air has weight owing to the
vapours and halations which ascend from the earth and seas to a height
of many miles and surround the whole of our terraqueous globe; and this
fact will not be denied by philosophers, even by those who may have
but a superficial knowledge, because it can be proven by exhausting,
if not all, at any rate the greater part of, the air contained in a
glass vessel, which, if weighed before and after the air has been
exhausted, will be found materially reduced in weight. Then I found
out how much the air weighed in itself in the following manner. I
procured a large vessel of glass, whose neck could be closed or opened
by means of a tap, and holding it open I warmed it over a fire, so
that the air inside it becoming rarified, the major part was forced
out; then quickly shutting the tap to prevent the re-entry I weighed
it; which done, I plunged its neck in water, resting the whole of the
vessel on the surface of the water, then on opening the tap the water
rose in the vessel and filled the greater part of it. I lifted the
neck out of the water, released the water contained in the vessel, and
measured and weighed its quantity and density, by which I inferred that
a certain quantity of air had come out of the vessel equal in bulk to
the quantity of water which had entered to refill the portion abandoned
by the air. I again weighed the vessel, after I had first of all well
dried it free of all moisture, and found it weighed one ounce more
whilst it was full of air than when it was exhausted of the greater
part, so that what it weighed more was a quantity of air equal in
volume to the water which took its place. The water weighed 640 ounces,
so I concluded that the weight of air compared with that of water was
1 to 640--that is to say, as the water which filled the vessel weighed
640 ounces, so the air which filled the same vessel weighed one ounce.’
Having thus detailed the method of exhausting air from a vessel, Lana
goes on to assume that any large vessel can be entirely exhausted
of nearly all the air contained therein. Then he takes Euclid’s
proposition to the effect that the superficial area of globes increases
in the proportion of the square of the diameter, whilst the volume
increases in the proportion of the cube of the same diameter, and he
considers that if one only constructs the globe of thin metal, of
sufficient size, and exhausts the air in the manner that he suggests,
such a globe will be so far lighter than the surrounding atmosphere
that it will not only rise, but will be capable of lifting weights.
Here is Lana’s own way of putting it:--
‘But so that it may be enabled to raise heavier weights and to lift
men in the air, let us take double the quantity of copper, 1,232
square feet, equal to 308 lbs. of copper; with this double quantity of
copper we could construct a vessel of not only double the capacity,
but of four times the capacity of the first, for the reason shown by
my fourth supposition. Consequently the air contained in such a vessel
will be 718 lbs. 4⅔ ounces, so that if the air be drawn out of the
vessel it will be 410 lbs. 4⅔ ounces lighter than the same volume of
air, and, consequently, will be enabled to lift three men, or at least
two, should they weigh more than eight pesi each. It is thus manifest
that the larger the ball or vessel is made, the thicker and more solid
can the sheets of copper be made, because, although the weight will
increase, the capacity of the vessel will increase to a greater extent
and with it the weight of the air therein, so that it will always be
capable to lift a heavier weight. From this it can be easily seen how
it is possible to construct a machine which, fashioned like unto a
ship, will float on the air.’
[Illustration: A suggestion for applying hydrogen gas to Lana’s ‘Aerial
Ship.’ Rome, 1784.]
With four globes of these dimensions Lana proposed to make an aerial
ship of the fashion shown in his quaint illustration. He is careful to
point out a method by which the supporting globes for the aerial ship
may be entirely emptied of air; this is to be done by connecting to
each globe a tube of copper which is ‘at least a length of 47 modern
Roman palmi.’ A small tap is to close this tube at the end nearest the
globe, and then vessel and tube are to be filled with water, after
which the tube is to be immersed in water and the tap opened, allowing
the water to run out of the vessel, while no air enters. The tap is
then closed before the lower end of the tube is removed from the water,
leaving no air at all in the globe or sphere. Propulsion of this
airship was to be accomplished by means of sails, and also by oars.
Lana antedated the modern propeller, and realised that the air would
offer enough resistance to oars or paddle to impart motion to any
vessel floating in it and propelled by these means, although he did
not realise the amount of pressure on the air which would be necessary
to accomplish propulsion. As a matter of fact, he foresaw and provided
against practically all the difficulties that would be encountered in
the working, as well as the making, of the aerial ship, finally coming
up against what his religious training made an insuperable objection.
This, again, is best told in his own words:--
‘Other difficulties I do not foresee that could prevail against this
invention, save one only, which to me seems the greatest of them all,
and that is that God would surely never allow such a machine to be
successful, since it would create many disturbances in the civil and
political governments of mankind.’
He ends by saying that no city would be proof against surprise, while
the aerial ship could set fire to vessels at sea, and destroy houses,
fortresses, and cities by fire balls and bombs. In fact, at the end of
his treatise on the subject, he furnishes a pretty complete _résumé_ of
the activities of German Zeppelins.
As already noted, Lana himself, owing to his vows of poverty, was
unable to do more than put his suggestions on paper, which he did with
a thoroughness that has procured him a place among the really great
pioneers of flying.
It was nearly 200 years before any attempt was made to realise his
project; then, in 1843, M. Marey Monge set out to make the globes and
the ship as Lana detailed them. Monge’s experiments cost him the sum
of 25,000 francs 75 centimes, which he expended purely from love of
scientific investigation. He chose to make his globes of brass, about
.004 in thickness, and weighing 1.465 lbs. to the square yard. Having
made his sphere of this metal, he lined it with two thicknesses of
tissue paper, varnished it with oil, and set to work to empty it of
air. This, however, he never achieved, for such metal is incapable of
sustaining the pressure of the outside air, as Lana, had he had the
means to carry out experiments, would have ascertained. M. Monge’s
sphere could never be emptied of air sufficiently to rise from the
earth; it ended in the melting-pot, ignominiously enough, and all that
Monge got from his experiment was the value of the scrap metal and the
satisfaction of knowing that Lana’s theory could never be translated
into practice.
Robert Hooke is less conspicuous than either Borelli or Lana; his
work, which came into the middle of the seventeenth century, consisted
of various experiments with regard to flight, from which emerged ‘a
Module, which by the help of Springs and Wings, raised and sustained
itself in the air.’ This must be reckoned as the first model flying
machine which actually flew, except for da Vinci’s helicopters; Hooke’s
model appears to have been of the flapping-wing type--he attempted to
copy the motion of birds, but found from study and experiment that
human muscles were not sufficient to the task of lifting the human
body. For that reason, he says, ‘I applied my mind to contrive a way
to make artificial muscles,’ but in this he was, as he expresses it,
‘frustrated of my expectations.’ Hooke’s claim to fame rests mainly on
his successful model; the rest of his work is of too scrappy a nature
to rank as a serious contribution to the study of flight.
Contemporary with Hooke was one Allard, who, in France, undertook to
emulate the Saracen of Constantinople to a certain extent. Allard was a
tight-rope dancer who either did or was said to have done short gliding
flights--the matter is open to question--and finally stated that he
would, at St Germains, fly from the terrace in the king’s presence. He
made the attempt, but merely fell, as did the Saracen some centuries
before, causing himself serious injury. Allard cannot be regarded as a
contributor to the development of aeronautics in any way, and is only
mentioned as typical of the way in which, up to the time of the Wright
brothers, flying was regarded. Even unto this day there are many who
still believe that, with a pair of wings, man ought to be able to fly,
and that the mathematical data necessary to effective construction
simply do not exist. This attitude was reasonable enough in an
unlearned age, and Allard was one--a little more conspicuous than the
majority--among many who made experiment in ignorance, with more or
less danger to themselves and without practical result of any kind.
[Illustration: Besnier’s Flying Apparatus.]
The seventeenth century was not to end, however, without practical
experiment of a noteworthy kind in gliding flight. Among the recruits
to the ranks of pioneers was a certain Besnier, a locksmith of Sablé,
who somewhere between 1675 and 1680 constructed a glider of which a
crude picture has come down to modern times. The apparatus, as will
be seen, consisted of two rods with hinged flaps, and the original
designer of the picture seems to have had but a small space in which to
draw, since obviously the flaps must have been much larger than those
shown. Besnier placed the rods on his shoulders, and worked the flaps
by cords attached to his hands and feet--the flaps opened as they fell,
and closed as they rose, so the device as a whole must be regarded as
a sort of flapping glider. Having by experiment proved his apparatus
successful, Besnier promptly sold it to a travelling showman of the
period, and forthwith set about constructing a second set, with which
he made gliding flights of considerable height and distance. Like
Lilienthal, Besnier projected himself into space from some height, and
then, according to the contemporary records, he was able to cross a
river of considerable size before coming to earth. It does not appear
that he had any imitators, or that any advantage whatever was taken
of his experiments; the age was one in which he would be regarded
rather as a freak exhibitor than as a serious student, and possibly,
considering his origin and the sale of his first apparatus to such a
client, he regarded the matter himself as more in the nature of an
amusement than as a discovery.
Borelli, coming at the end of the century, proved to his own
satisfaction and that of his fellows that flapping wing flight was an
impossibility; the capabilities of the plane were as yet undreamed, and
the prime mover that should make the plane available for flight was
deep in the womb of time. Da Vinci’s work was forgotten--flight was an
impossibility, or at best such a useless show as Besnier was able to
give.
The eighteenth century was almost barren of experiment. Emanuel
Swedenborg, having invented a new religion, set about inventing a
flying machine, and succeeded theoretically, publishing the result of
his investigations as follows:--
‘Let a car or boat or some like object be made of light material such
as cork or bark, with a room within it for the operator. Secondly, in
front as well as behind, or all round, set a widely-stretched sail
parallel to the machine, forming within a hollow or bend, which could
be reefed like the sails of a ship. Thirdly, place wings on the sides,
to be worked up and down by a spiral spring, these wings also to be
hollow below in order to increase the force and velocity, take in
the air, and make the resistance as great as may be required. These,
too, should be of light material and of sufficient size; they should
be in the shape of birds’ wings, or the sails of a windmill, or some
such shape, and should be tilted obliquely upwards, and made so as to
collapse on the upward stroke and expand on the downward. Fourth, place
a balance or beam below, hanging down perpendicularly for some distance
with a small weight attached to its end, pendent exactly in line with
the centre of gravity; the longer this beam is, the lighter must it
be, for it must have the same proportion as the well-known vectis or
steel-yard. This would serve to restore the balance of the machine if
it should lean over to any of the four sides. Fifthly, the wings would
perhaps have greater force, so as to increase the resistance and make
the flight easier, if a hood or shield were placed over them, as is
the case with certain insects. Sixthly, when the sails are expanded
so as to occupy a great surface and much air, with a balance keeping
them horizontal, only a small force would be needed to move the machine
back and forth in a circle, and up and down. And, after it has gained
momentum to move slowly upwards, a slight movement and an even bearing
would keep it balanced in the air and would determine its direction at
will.’
The only point in this worthy of any note is the first device for
maintaining stability automatically--Swedenborg certainly scored a
point there. For the rest, his theory was but theory, incapable of
being put to practice--he does not appear to have made any attempt at
advance beyond the mere suggestion.
Some ten years before his time the state of knowledge with regard to
flying in Europe was demonstrated by an order granted by the King of
Portugal to Friar Lourenzo de Guzman, who claimed to have invented a
flying machine capable of actual flight. The order stated that ‘In
order to encourage the suppliant to apply himself with zeal toward
the improvement of the new machine, which is capable of producing the
effects mentioned by him, I grant unto him the first vacant place in
my College of Barcelos or Santarem, and the first professorship of
mathematics in my University of Coimbra, with the annual pension of
600,000 reis during his life.--Lisbon, 17th of March, 1709.’
What happened to Guzman when the non-existence of the machine was
discovered is one of the things that is well outside the province of
aeronautics. He was charlatan pure and simple, as far as actual flight
was concerned, though he had some ideas respecting the design of
hot-air balloons, according to Tissandier. (_La Navigation Aerienne._)
His flying machine was to contain, among other devices, bellows to
produce artificial wind when the real article failed, and also magnets
in globes to draw the vessel in an upward direction and maintain its
buoyancy. Some draughtsman, apparently gifted with as vivid imagination
as Guzman himself, has given to the world an illustration of the
hypothetical vessel; it bears some resemblance to Lana’s aerial ship,
from which fact one draws obvious conclusions.
A rather amusing claim to solving the problem of flight was made in
the middle of the eighteenth century by one Grimaldi, a ‘famous
and unique Engineer’ who, as a matter of actual fact, spent twenty
years in missionary work in India, and employed the spare time that
missionary work left him in bringing his invention to a workable state.
The invention is described as a ‘box which with the aid of clockwork
rises in the air, and goes with such lightness and strong rapidity
that it succeeds in flying a journey of seven leagues in an hour. It
is made in the fashion of a bird; the wings from end to end are 25
feet in extent. The body is composed of cork, artistically joined
together and well fastened with metal wire, covered with parchment
and feathers. The wings are made of catgut and whalebone, and covered
also with the same parchment and feathers, and each wing is folded
in three seams. In the body of the machine are contained thirty
wheels of unique work, with two brass globes and little chains which
alternately wind up a counterpoise; with the aid of six brass vases,
full of a certain quantity of quicksilver, which run in some pulleys,
the machine is kept by the artist in due equilibrium and balance. By
means, then, of the friction between a steel wheel adequately tempered
and a very heavy and surprising piece of lodestone, the whole is kept
in a regulated forward movement, given, however, a right state of the
winds, since the machine cannot fly so much in totally calm weather as
in stormy. This prodigious machine is directed and guided by a tail
seven palmi long, which is attached to the knees and ankles of the
inventor by leather straps; by stretching out his legs, either to the
right or to the left, he moves the machine in whichever direction he
pleases.... The machine’s flight lasts only three hours, after which
the wings gradually close themselves, when the inventor, perceiving
this, goes down gently, so as to get on his own feet, and then winds
up the clockwork and gets himself ready again upon the wings for the
continuation of a new flight. He himself told us that if by chance one
of the wheels came off or if one of the wings broke, it is certain he
would inevitably fall rapidly to the ground, and, therefore, he does
not rise more than the height of a tree or two, as also he only once
put himself in the risk of crossing the sea, and that was from Calais
to Dover, and the same morning he arrived in London.’
And yet there are still quite a number of people who persist in stating
that Bleriot was the first man to fly across the Channel!
A study of the development of the helicopter principle was published
in France in 1868, when the great French engineer Paucton produced his
_Théorie de la Vis d’Archiméde_. For some inexplicable reason, Paucton
was not satisfied with the term ‘helicopter,’ but preferred to call it
a ‘ptérophore,’ a name which, so far as can be ascertained, has not
been adopted by any other writer or investigator. Paucton stated that,
since a man is capable of sufficient force to overcome the weight of
his own body, it is only necessary to give him a machine which acts on
the air ‘with all the force of which it is capable and at its utmost
speed,’ and he will then be able to lift himself in the air, just as
by the exertion of all his strength he is able to lift himself in
water. ‘It would seem,’ says Paucton, ‘that in the ptérophore, attached
vertically to a carriage, the whole built lightly and carefully
assembled, he has found something that will give him this result in all
perfection. In construction, one would be careful that the machine
produced the least friction possible, and naturally it ought to produce
little, as it would not be at all complicated. The new Dædalus, sitting
comfortably in his carriage, would by means of a crank give to the
ptérophore a suitable circular (or revolving) speed. This single
ptérophore would lift him vertically, but in order to move horizontally
he should be supplied with a tail in the shape of another ptérophore.
When he wished to stop for a little time, valves fixed firmly across
the end of the space between the blades would automatically close the
openings through which the air flows, and change the ptérophore into an
unbroken surface which would resist the flow of air and retard the fall
of the machine to a considerable degree.’
The doctrine thus set forth might appear plausible, but it is based
on the common misconception that all the force which might be put
into the helicopter or ‘ptérophore’ would be utilised for lifting
or propelling the vehicle through the air, just as a propeller uses
all its power to drive a ship through water. But, in applying such
a propelling force to the air, most of the force is utilised in
maintaining aerodynamic support--as a matter of fact, more force is
needed to maintain this support than the muscle of man could possibly
furnish to a lifting screw, and even if the helicopter were applied
to a full-sized, engine-driven air vehicle, the rate of ascent would
depend on the amount of surplus power that could be carried. For
example, an upward lift of 1,000 pounds from a propeller 15 feet in
diameter would demand an expenditure of 50 horse-power under the best
possible conditions, and in order to lift this load vertically through
such atmospheric pressure as exists at sea-level or thereabouts, an
additional 20 horse-power would be required to attain a rate of 11
feet per second--50 horse-power must be continually provided for the
mere support of the load, and the additional 20 horse-power must be
continually provided in order to lift it. Although, in model form,
there is nothing quite so strikingly successful as the helicopter in
the range of flying machines, yet the essential weight increases so
disproportionately to the effective area that it is necessary to go but
very little beyond model dimensions for the helicopter to become quite
ineffective.
That is not to say that the lifting screw must be totally ruled out
so far as the construction of aircraft is concerned. Much is still
empirical, so far as this branch of aeronautics is concerned, and
consideration of the structural features of a propeller goes to show
that the relations of essential weight and effective area do not
altogether apply in practice as they stand in theory. Paucton’s dream,
in some modified form, may yet become reality--it is only so short
a time ago as 1896 that Lord Kelvin stated he had not the smallest
molecule of faith in aerial navigation, and since the whole history of
flight consists in proving the impossible possible, the helicopter may
yet challenge the propelled plane surface for aerial supremacy.
It does not appear that Paucton went beyond theory, nor is there in
his theory any advance toward practical flight--da Vinci could have
told him as much as he knew. He was followed by Meerwein, who invented
an apparatus apparently something between a flapping wing machine
and a glider, consisting of two wings, which were to be operated by
means of a rod; the venturesome one who would fly by means of this
apparatus had to lie in a horizontal position beneath the wings to work
the rod. Meerwein deserves a place of mention, however, by reason of
his investigations into the amount of surface necessary to support a
given weight. Taking that weight at 200 pounds--which would allow for
the weight of a man and a very light apparatus--he estimated that 126
square feet would be necessary for support. His pamphlet, published
at Basle in 1784, shows him to have been a painstaking student of the
potentialities of flight.
Jean-Pierre Blanchard, later to acquire fame in connection with
balloon flight, conceived and described a curious vehicle, of which
he even announced trials as impending. His trials were postponed time
after time, and it appears that he became convinced in the end of
the futility of his device, being assisted to such a conclusion by
Lalande, the astronomer, who repeated Borelli’s statement that it was
impossible for man ever to fly by his own strength. This was in the
closing days of the French monarchy, and the ascent of the Mongolfiers’
first hot-air balloon in 1783--which shall be told more fully in its
place--put an end to all French experiments with heavier-than-air
apparatus, though in England the genius of Cayley was about to bud, and
even in France there were those who understood that ballooning was not
true flight.
III
SIR GEORGE CAYLEY--THOMAS WALKER
On the fifth of June, 1783, the Montgolfiers’ hot-air balloon rose
at Versailles, and in its rising divided the study of the conquest
of the air into two definite parts, the one being concerned with the
propulsion of gas lifted, lighter-than-air vehicles, and the other
being crystallised in one sentence by Sir George Cayley: ‘The whole
problem,’ he stated, ‘is confined within these limits, viz.: to make
a surface support a given weight by the application of power to the
resistance of the air.’ For about ten years the balloon held the field
entirely, being regarded as the only solution of the problem of flight
that man could ever compass. So definite for a time was this view on
the eastern side of the Channel that for some years practically all the
progress that was made in the development of power-driven planes was
made in Britain.
In 1800 a certain Dr Thomas Young demonstrated that certain curved
surfaces suspended by a thread moved into and not away from a
horizontal current of air, but the demonstration, which approaches
perilously near to perpetual motion if the current be truly horizontal,
has never been successfully repeated, so that there is more than a
suspicion that Young’s air-current was _not_ horizontal. Others had
made and were making experiments on the resistance offered to the air
by flat surfaces, when Cayley came to study and record, earning such
a place among the pioneers as to win the title of ‘father of British
aeronautics.’
Cayley was a man in advance of his time, in many ways. Of independent
means, he made the grand tour which was considered necessary to the
education of every young man of position, and during this excursion
he was more engaged in studies of a semi-scientific character than in
the pursuits that normally filled such a period. His various writings
prove that throughout his life aeronautics was the foremost subject
in his mind; the _Mechanic’s Magazine_, _Nicholson’s Journal_, the
_Philosophical Magazine_, and other periodicals of like nature bear
witness to Cayley’s continued research into the subject of flight.
He approached the subject after the manner of the trained scientist,
analysing the mechanical properties of air under chemical and physical
action. Then he set to work to ascertain the power necessary for aerial
flight, and was one of the first to enunciate the fallacy of the hopes
of successful flight by means of the steam engine of those days, owing
to the fact that it was impossible to obtain a given power with a given
weight.
Yet his conclusions on this point were not altogether negative, for as
early as 1810 he stated that he could construct a balloon which could
travel with passengers at 20 miles an hour--he was one of the first
to consider the possibilities of applying power to a balloon. Nearly
thirty years later--in 1837--he made the first attempt at establishing
an aeronautical society, but at that time the power-driven plane was
regarded by the great majority as an absurd dream of more or less
mad inventors, while ballooning ranked on about the same level as
tight-rope walking, being considered an adjunct to fairs and fêtes,
more a pastime than a study.
Up to the time of his death, in 1857, Cayley maintained his study of
aeronautical matters, and there is no doubt whatever that his work
went far in assisting the solution of the problem of air conquest. His
principal published work, a monograph entitled _Aerial Navigation_, has
been republished in the admirable series of ‘Aeronautical Classics’
issued by the Royal Aeronautical Society. He began this work by
pointing out the impossibility of flying by means of attached wrings,
an impossibility due to the fact that, while the pectoral muscles of a
bird account for more than two-thirds of its whole muscular strength,
in a man the muscles available for flying, no matter what mechanism
might be used, would not exceed one-tenth of his total strength.
Cayley did not actually deny the possibility of a man flying by
muscular effort, however, but stated that ‘the flight of a strong
man by great muscular exertion, though a curious and interesting
circumstance, inasmuch as it will probably be the means of ascertaining
this power and supplying the basis whereon to improve it, would be of
little use.’
From this he goes on to the possibility of using a Boulton and Watt
steam engine to develop the power necessary for flight, and in this
he saw a possibility of practical result. It is worthy of note that
in this connection he made mention of the forerunner of the modern
internal combustion engine; ‘The French,’ he said, ‘have lately shown
the great power produced by igniting inflammable powders in closed
vessels, and several years ago an engine was made to work in this
country in a similar manner by inflammation of spirit of tar.’ In a
subsequent paragraph of his monograph he anticipates almost exactly the
construction of the Lenoir gas engine, which came into being more than
fifty-five years after his monograph was published.
Certain experiments detailed in his work were made to ascertain the
size of the surface necessary for the support of any given weight.
He accepted a truism of to-day in pointing out that in any matters
connected with aerial investigation, theory and practice are as
widely apart as the poles. Inclined at first to favour the helicopter
principle, he finally rejected this in favour of the plane, with
which he made numerous experiments. During these, he ascertained the
peculiar advantages of curved surfaces, and saw the necessity of
providing both vertical and horizontal rudders in order to admit of
side steering as well as the control of ascent and descent, and for
preserving equilibrium. He may be said to have anticipated the work of
Lilienthal and Pilcher, since he constructed and experimented with a
fixed surface glider. ‘It was beautiful,’ he wrote concerning this, ‘to
see this noble white bird sailing majestically from the top of a hill
to any given point of the plain below it with perfect steadiness and
safety, according to the set of its rudder, merely by its own weight,
descending at an angle of about eight degrees with the horizon.’
[Illustration: Sir George Caley, Bart.
‘The Father of British Aeronautics.’]
It is said that he once persuaded his gardener to trust himself in this
glider for a flight, but if Cayley himself ventured a flight in it he
has left no record of the fact. The following extract from his work,
_Aerial Navigation_, affords an instance of the thoroughness of his
investigations, and the concluding paragraph also shows his faith in
the ultimate triumph of mankind in the matter of aerial flight:--
‘The act of flying requires less exertion than from the appearance is
supposed. Not having sufficient data to ascertain the exact degree of
propelling power exerted by birds in the act of flying, it is uncertain
what degree of energy may be required in this respect for vessels of
aerial navigation; yet when we consider the many hundreds of miles of
continued flight exerted by birds of passage, the idea of its being
only a small effort is greatly corroborated. To apply the power of
the first mover to the greatest advantage in producing this effect is
a very material point. The mode universally adopted by Nature is the
oblique waft of the wing. We have only to choose between the direct
beat overtaking the velocity of the current, like the oar of a boat, or
one applied like the wing, in some assigned degree of obliquity to it.
Suppose 35 feet per second to be the velocity of an aerial vehicle, the
oar must be moved with this speed previous to its being able to receive
any resistance; then if it be only required to obtain a pressure of
one-tenth of a lb. upon each square foot it must exceed the velocity
of the current 7.3 feet per second. Hence its whole velocity must be
42.5 feet per second. Should the same surface be wafted downward like a
wing with the hinder edge inclined upward in an angle of about 50 deg.
40 feet to the current it will overtake it at a velocity of 3.5 feet
per second; and as a slight unknown angle of resistance generates a lb.
pressure per square foot at this velocity, probably a waft of a little
more than 4 feet per second would produce this effect, one-tenth part
of which would be the propelling power. The advantage of this mode of
application compared with the former is rather more than ten to one.
‘In continuing the general principles of aerial navigation, for the
practice of the art, many mechanical difficulties present themselves
which require a considerable course of skilfully applied experiments
before they can be overcome; but, to a certain extent, the air has
already been made navigable, and no one who has seen the steadiness
with which weights to the amount of ten stone (including four stone,
the weight of the machine) hover in the air can doubt of the ultimate
accomplishment of this object.’
This extract from his work gives but a faint idea of the amount of
research for which Cayley was responsible. He had the humility of the
true investigator in scientific problems, and so far as can be seen
was never guilty of the great fault of so many investigators in this
subject--that of making claims which he could not support. He was
content to do, and pass after having recorded his part, and although
nearly half a century had to pass between the time of his death and the
first actual flight by means of power-driven planes, yet he may be said
to have contributed very largely to the solution of the problem, and
his name will always rank high in the roll of the pioneers of flight.
Practically contemporary with Cayley was Thomas Walker, concerning whom
little is known save that he was a portrait painter of Hull, where was
published his pamphlet on _The Art of Flying_ in 1810, a second and
amplified edition being produced, also in Hull, in 1831. The pamphlet,
which has been reproduced _in extenso_ in the _Aeronautical Classics_
series published by the Royal Aeronautical Society, displays a curious
mixture of the true scientific spirit and colossal conceit. Walker
appears to have been a man inclined to jump to conclusions, which
carried him up to the edge of discovery and left him vacillating there.
The study of the two editions of his pamphlet side by side shows that
their author made considerable advances in the practicability of
his designs in the 21 intervening years, though the drawings which
accompany the text in both editions fail to show anything really
capable of flight. The great point about Walker’s work as a whole is
its suggestiveness; he did not hesitate to state that the ‘art’ of
flying is as truly mechanical as that of rowing a boat, and he had
some conception of the necessary mechanism, together with an absolute
conviction that he knew all there was to be known. ‘Encouraged by the
public,’ he says, ‘I would not abandon my purpose of making still
further exertions to advance and complete an art, the discovery of the
_true principles_ (the italics are Walker’s own) of which, I trust, I
can with certainty affirm to be my own.’
The pamphlet begins with Walker’s admiration of the mechanism of flight
as displayed by birds. ‘It is now almost twenty years,’ he says, ‘since
I was first led to think, by the study of birds and their means of
flying, that if an artificial machine were formed with wings in exact
imitation of the mechanism of one of those beautiful living machines,
and applied in the very same way upon the air, there could be no doubt
of its being made to fly, for it is an axiom in philosophy that the
same cause will ever produce the same effect.’ With this he confesses
his inability to produce the said effect through lack of funds, though
he clothes this delicately in the phrase ‘professional avocations and
other circumstances.’ Owing to this inability he published his designs
that others might take advantage of them, prefacing his own researches
with a list of the very early pioneers, and giving special mention to
Friar Bacon, Bishop Wilkins, and the Portuguese friar, De Guzman. But,
although he seems to suggest that others should avail themselves of
his theoretical knowledge, there is a curious incompleteness about the
designs accompanying his work, and about the work itself, which seems
to suggest that he had more knowledge to impart than he chose to make
public--or else that he came very near to complete solution of the
problem of flight, and stayed on the threshold without knowing it.
After a dissertation upon the history and strength of the condor,
and on the differences between the weights of birds, he says: ‘The
following observations upon the wonderful difference in the weight of
some birds, with their apparent means of supporting it in their flight,
may tend to remove some prejudices against my plan from the minds of
some of my readers. The weight of the humming-bird is one drachm, that
of the condor not less than four stone. Now, if we reduce four stone
into drachms we shall find the condor is 14,336 times as heavy as the
humming-bird. What an amazing disproportion of weight! Yet by the
same mechanical use of its wings the condor can overcome the specific
gravity of its body with as much ease as the little humming-bird. But
this is not all. We are informed that this enormous bird possesses a
power in its wings, so far exceeding what is necessary for its own
conveyance through the air, that it can take up and fly away with a
whole sheep in its talons, with as much ease as an eagle would carry
off, in the same manner, a hare or a rabbit. This we may readily
give credit to, from the known fact of our little kestrel and the
sparrowhawk frequently flying off with a partridge, which is nearly
three times the weight of these rapacious little birds.’
After a few more observations he arrives at the following conclusion:
‘By attending to the progressive increase in the weight of birds, from
the delicate little humming-bird up to the huge condor, we clearly
discover that the addition of a few ounces, pounds, or stones, is no
obstacle to the art of flying; the specific weight of birds avails
nothing, for by their possessing wings large enough, and sufficient
power to work them, they can accomplish the means of flying equally
well upon all the various scales and dimensions which we see in nature.
Such being a fact, in the name of reason and philosophy why shall not
man, with a pair of artificial wings, large enough, and with sufficient
power to strike them upon the air, be able to produce the same effect?’
Walker asserted definitely and with good ground that muscular effort
applied without mechanism is insufficient for human flight, but he
states that if an aeronautical boat were constructed so that a man
could sit in it in the same manner as when rowing, such a man would
be able to bring into play his whole bodily strength for the purpose
of flight, and at the same time would be able to get an additional
advantage by exerting his strength upon a lever. At first he concluded
there must be expansion of wings large enough to resist in a sufficient
degree the specific gravity of whatever is attached to them, but in
the second edition of his work he altered this to ‘expansion of flat
passive surfaces large enough to reduce the force of gravity so as
to float the machine upon the air with the man in it.’ The second
requisite is strength enough to strike the wings with sufficient force
to complete the buoyancy and give a projectile motion to the machine.
Given these two requisites, Walker states definitely that flying must
be accomplished simply by muscular exertion. ‘If we are secure of these
two requisites, and I am very confident we are, we may calculate upon
the success of flight with as much certainty as upon our walking.’
Walker appears to have gained some confidence from the experiments
of a certain M. Degen, a watchmaker of Vienna, who, according to the
_Monthly Magazine_ of September, 1809, invented a machine by means of
which a person might raise himself into the air. The said machine,
according to the magazine, was formed of two parachutes which might be
folded up or extended at pleasure, while the person who worked them was
placed in the centre. This account, however, was rather misleading,
for the magazine carefully avoided mention of a balloon to which the
inventor fixed his wings or parachutes. Walker, knowing nothing of
the balloon, concluded that Degen actually raised himself in the air,
though he is doubtful of the assertion that Degen managed to fly in
various directions, especially against the wind.
Walker, after considering Degen and all his works, proceeds to detail
his own directions for the construction of a flying machine, these
being as follows: ‘Make a car of as light material as possible, but
with sufficient strength to support a man in it; provide a pair of
wings about four feet each in length; let them be horizontally expanded
and fastened upon the top edge of each side of the car, with two
joints each, so as to admit of a vertical motion to the wings, which
motion may be effected by a man sitting and working an upright lever in
the middle of the car. Extend in the front of the car a flat surface of
silk, which must be stretched out and kept fixed in a passive state;
there must be the same fixed behind the car; these two surfaces must
be perfectly equal in length and breadth and large enough to cover a
sufficient quantity of air to support the whole weight as nearly in
equilibrium as possible, thus we shall have a great sustaining power
in those passive surfaces and the active wings will propel the car
forward.’
A description of how to launch this car is subsequently given: ‘It
becomes necessary,’ says the theorist, ‘that I should give directions
how it may be launched upon the air, which may be done by various
means; perhaps the following method may be found to answer as well as
any: Fix a poll upright in the earth, about twenty feet in height,
with two open collars to admit another poll to slide upwards through
them; let there be a sliding platform made fast upon the top of the
sliding poll; place the car with a man in it upon the platform, then
raise the platform to the height of about thirty feet by means of the
sliding poll, let the sliding poll and platform suddenly fall down,
the car will then be left upon the air, and by its pressing the air
a projectile force will instantly propel the car forward; the man in
the car must then strike the active wings briskly upon the air, which
will so increase the projectile force as to become superior to the
force of gravitation, and if he inclines his weight a little backward,
the projectile impulse will drive the car forward in an ascending
direction. When the car is brought to a sufficient altitude to clear
the tops of hills, trees, buildings, etc., the man, by sitting a little
forward on his seat, will then bring the wings upon a horizontal plane,
and by continuing the action of the wings he will be impelled forward
in that direction. To descend, he must desist from striking the wings,
and hold them on a level with their joints; the car will then gradually
come down, and when it is within five or six feet of the ground the man
must instantly strike the wings downwards, and sit as far back as he
can; he will by this means check the projectile force, and cause the
car to alight very gently with a retrograde motion. The car, when up
in the air, may be made to turn to the right or to the left by forcing
out one of the fins, having one about eighteen inches long placed
vertically on each side of the car for that purpose, or perhaps merely
by the man inclining the weight of his body to one side.’
Having stated how the thing is to be done, Walker is careful to explain
that when it is done there will be in it some practical use, notably
in respect of the conveyance of mails and newspapers, or the saving of
life at sea, or for exploration, etc. It might even reduce the number
of horses kept by man for his use, by means of which a large amount of
land might be set free for the growth of food for human consumption.
At the end of his work Walker admits the idea of steam power for
driving a flying machine in place of simple human exertion, but he,
like Cayley, saw a drawback to this in the weight of the necessary
engine. On the whole, he concluded, navigation of the air by means of
engine power would be mostly confined to the construction of navigable
balloons.
As already noted, Walker’s work is not over practical, and the
foregoing extract includes the most practical part of it; the rest is
a series of dissertations on bird flight, in which, evidently, the
portrait painter’s observations were far less thorough than those
of da Vinci or Borelli. Taken on the whole, Walker was a man with a
hobby; he devoted to it much time and thought, but it remained a hobby,
nevertheless. His observations have proved useful enough to give him a
place among the early students of flight, but a great drawback to his
work is the lack of practical experiment, by means of which alone real
advance could be made; for, as Cayley admitted, theory and practice are
very widely separated in the study of aviation, and the whole history
of flight is a matter of unexpected results arising from scarcely
foreseen causes, together with experiment as patient as daring.
IV
THE MIDDLE NINETEENTH CENTURY
Both Cayley and Walker were theorists, though Cayley supported his
theoretical work with enough of practice to show that he studied
along right lines; a little after his time there came practical men
who brought to being the first machine which actually flew by the
application of power. Before their time, however, mention must be made
of the work of George Pocock of Bristol, who, somewhere about 1840,
invented what was described as a ‘kite carriage,’ a vehicle which
carried a number of persons, and obtained its motive power from a large
kite. It is on record that, in the year 1846, one of these carriages
conveyed sixteen people from Bristol to London. Another device of
Pocock’s was what he called a ‘buoyant sail,’ which was in effect
a man-lifting kite, and by means of which a passenger was actually
raised 100 yards from the ground, while the inventor’s son scaled a
cliff 200 feet in height by means of one of these ‘buoyant sails.’
This constitutes the first definitely recorded experiment in the use
of man-lifting kites. _A History of the Charvolant or Kite-Carriage_,
published in London in 1851, states that ‘an experiment of a bold
and very novel character was made upon an extensive down, where a
large wagon with a considerable load was drawn along, whilst this
huge machine at the same time carried an observer aloft in the air,
realising almost the romance of flying.’
Experimenting, two years after the appearance of the ‘kite-carriage,’
on the helicopter principle, W. H. Phillips constructed a model
machine which weighed two pounds; this was fitted with revolving fans,
driven by the combustion of charcoal, nitre, and gypsum, producing
steam which, discharging into the air, caused the fans to revolve.
The inventor stated that ‘all being arranged, the steam was up in a
few seconds, when the whole apparatus spun around like any top, and
mounted into the air faster than a bird; to what height it ascended
I had no means of ascertaining; the distance travelled was across
two fields, where, after a long search, I found the machine minus
the wings, which had been torn off in contact with the ground.’ This
could hardly be described as successful flight, but it was an advance
in the construction of machines on the helicopter principle, and it
was the first steam-driven model of the type which actually flew. The
invention, however, was not followed up.
After Phillips, we come to the great figures of the middle nineteenth
century, W. S. Henson and John Stringfellow. Cayley had shown, in 1809,
how success might be attained by developing the idea of the plane
surface so driven as to take advantage of the resistance offered by
the air, and Henson, who as early as 1840 was experimenting with model
gliders and light steam engines, evolved and patented an idea for
something very nearly resembling the monoplane of the early twentieth
century. His patent, No. 9478, of the year 1842, explains the principle
of the machine as follows:--
‘In order that the description hereafter given may be rendered clear,
I will first shortly explain the principle on which the machine is
constructed. If any light and flat or nearly flat article be projected
or thrown edgewise in a slightly inclined position, the same will
rise on the air till the force exerted is expended, when the article
so thrown or projected will descend; and it will readily be conceived
that, if the article so projected or thrown possessed in itself a
continuous power or force equal to that used in throwing or projecting
it, the article would continue to ascend so long as the forward part
of the surface was upwards in respect to the hinder part, and that
such article, when the power was stopped, or when the inclination was
reversed, would descend by gravity aided by the force of the power
contained in the article, if the power be continued, thus imitating the
flight of a bird.
[Illustration: Henson’s proposed flying machine.]
[Illustration: Stringfellow’s power-driven model--the first model to
achieve engine-driven flight.]
Now, the first part of my invention consists of an apparatus so
constructed as to offer a very extended surface or plane of a light yet
strong construction, which will have the same relation to the general
machine which the extended wings of a bird have to the body when a
bird is skimming in the air; but in place of the movement or power for
onward progress being obtained by movement of the extended surface
or plane, as is the case with the wings of birds, I apply suitable
paddle-wheels or other proper mechanical propellers worked by a steam
or other sufficiently light engine, and thus obtain the requisite
power for onward movement to the plane or extended surface; and in
order to give control as to the upward and downward direction of such
a machine I apply a tail to the extended surface which is capable of
being inclined or raised, so that when the power is acting to propel
the machine, by inclining the tail upwards, the resistance offered
by the air will cause the machine to rise on the air; and, on the
contrary, when the inclination of the tail is reversed, the machine
will immediately be propelled downwards, and pass through a plane more
or less inclined to the horizon as the inclination of the tail is
greater or less; and in order to guide the machine as to the lateral
direction which it shall take, I apply a vertical rudder or second
tail, and, according as the same is inclined in one direction or the
other, so will be the direction of the machine.’
The machine in question was very large, and differed very little from
the modern monoplane; the materials were to be spars of bamboo and
hollow wood, with diagonal wire bracing. The surface of the planes was
to amount to 4,500 square feet, and the tail, triangular in form (here
modern practice diverges) was to be 1,500 square feet. The inventor
estimated that there would be a sustaining power of half a pound per
square foot, and the driving power was to be supplied by a steam engine
of 25 to 30 horse-power, driving two six-bladed propellers. Henson was
largely dependent on Stringfellow for many details of his design, more
especially with regard to the construction of the engine.
The publication of the patent attracted a great amount of public
attention, and the illustrations in contemporary journals, representing
the machine flying over the pyramids and the Channel, anticipated
fact by sixty years and more; the scientific world was divided, as it
was up to the actual accomplishment of flight, as to the value of the
invention.
Stringfellow and Henson became associated, after the conception of
their design, with an attorney named Colombine, and a Mr Marriott, and
between the four of them a project grew for putting the whole thing on
a commercial basis--Henson and Stringfellow were to supply the idea;
Marriott, knowing a member of Parliament, would be useful in getting a
company incorporated, and Colombine would look after the purely legal
side of the business. Thus an application was made by Mr Roebuck,
Marriott’s M.P., for an act of incorporation for ‘The Aerial Steam
Transit Company,’ Roebuck moving to bring in the bill on the 24th of
March, 1843. The prospectus, calling for funds for the development of
the invention, makes interesting reading at this stage of aeronautical
development; it was as follows:--
PROPOSAL.
For subscriptions of sums of £100, in furtherance of an
Extraordinary Invention not at present safe to be developed by
securing the necessary Patents, for which three times the sum
advanced, namely, £300, is conditionally guaranteed for each
subscription on February 1, 1844, in case of the anticipations
being realised, with the option of the subscribers being
shareholders for the large amount if so desired, but not otherwise.
* * * * *
An Invention has recently been discovered, which if ultimately
successful will be without parallel even in the age which
introduced to the world the wonderful effects of gas and of steam.
The discovery is of that peculiar nature, so simple in principle
yet so perfect in all the ingredients required for complete and
permanent success, that to promulgate it at present would wholly
defeat its development by the immense competition which would
ensue, and the views of the originator be entirely frustrated.
This work, the result of years of labour and study, presents a
wonderful instance of the adaptation of laws long since proved
to the scientific world combined with established principles so
judiciously and carefully arranged, as to produce a discovery
perfect in all its parts and alike in harmony with the laws of
Nature and of science.
The Invention has been subjected to several tests and examinations
and the results are most satisfactory, so much so that nothing
but the completion of the undertaking is required to determine
its practical operation, which being once established its utility
is undoubted, as it would be a necessary possession of every
empire, and it were hardly too much to say, of every individual of
competent means in the civilised world.
Its qualities and capabilities are so vast that it were impossible
and, even if possible, unsafe to develop them further, but some
idea may be formed from the fact that as a preliminary measure
patents in Great Britain, Ireland, Scotland, the Colonies, France,
Belgium, and the United States, and every other country where
protection to the first discoveries of an Invention is granted,
will of necessity be immediately obtained, and by the time these
are perfected, which it is estimated will be in the month of
February, the Invention will be fit for Public Trial, but until the
Patents are sealed any further disclosure would be most dangerous
to the principle on which it is based.
Under these circumstances, it is proposed to raise an immediate
sum of £2,000 in furtherance of the Projector’s views, and as
some protection to the parties who may embark in the matter, that
this is not a visionary plan for objects imperfectly considered,
Mr Colombine, to whom the secret has been confided, has allowed
his name to be used on the occasion, and who will if referred
to corroborate this statement, and convince any inquirer of the
reasonable prospects of large pecuniary results following the
development of the Invention.
It is, therefore, intended to raise the sum of £2,000 in twenty
sums of £100 each (of which any subscriber may take one or more not
exceeding five in number to be held by any individual) the amount
of which is to be paid into the hands of Mr Colombine as General
Manager of the concern to be by him appropriated in procuring the
several Patents and providing the expenses incidental to the works
in progress. For each of which sums of £100 it is intended and
agreed that twelve months after the 1st February next, the several
parties subscribing shall receive as an equivalent for the risk to
be run the sum of £300 for each of the sums of £100 now subscribed,
provided when the time arrives the Patents shall be found to answer
the purposes intended.
As full and complete success is alone looked to, no moderate or
imperfect benefit is to be anticipated, but the work, if it once
passes the necessary ordeal, to which inventions of every kind
must be first subject, will then be regarded by every one as the
most astonishing discovery of modern times; no half success can
follow, and therefore the full nature of the risk is immediately
ascertained.
The intention is to work and prove the Patent by collective instead
of individual aid as less hazardous at first and more advantageous
in the result for the Inventor, as well as others, by having the
interest of several engaged in aiding one common object--the
development of a Great Plan. The failure is not feared, yet as
perfect success might, by possibility, not ensue, it is necessary
to provide for that result, and the parties concerned make it a
condition that no return of the subscribed money shall be required,
if the Patents shall by any unforeseen circumstances not be capable
of being worked at all; against which, the first application of
the money subscribed, that of securing the Patents, affords a
reasonable security, as no one without solid grounds would think of
such an expenditure.
It is perfectly needless to state that no risk or responsibility of
any kind can arise beyond the payment of the sum to be subscribed
under any circumstances whatever.
As soon as the Patents shall be perfected and proved it is
contemplated, so far as may be found practicable, to further the
great object in view a Company shall be formed but respecting which
it is unnecessary to state further details, than that a preference
will be given to all those persons who now subscribe, and to whom
shares shall be appropriated according to the larger amount (being
three times the sum to be paid by each person) contemplated to
be returned as soon as the success of the Invention shall have
been established, at their option, or the money paid, whereby the
Subscriber will have the means of either withdrawing with a large
pecuniary benefit, or by continuing his interest in the concern,
lay the foundation for participating in the immense benefit which
must follow the success of the plan.
It is not pretended to conceal that the project is a
speculation--all parties believe that perfect success, and thence
incalculable advantage of every kind, will follow to every
individual joining in this great undertaking; but the Gentlemen
engaged in it wish that no concealment of the consequences, perfect
success, or possible failure, should in the slightest degree
be inferred. They believe this will prove the germ of a mighty
work, and in that belief call for the operation of others with no
visionary object, but a legitimate one before them, to attain that
point where perfect success will be secured from their combined
exertions.
All applications to be made to D. E. Colombine, Esquire, 8 Carlton
Chambers, Regent Street.
The applications did not materialise, as was only to be expected in
view of the vagueness of the proposals. Colombine did some advertising,
and Mr Roebuck expressed himself as unwilling to proceed further in the
venture. Henson experimented with models to a certain extent, while
Stringfellow looked for funds for the construction of a full-sized
monoplane. In November of 1843 he suggested that he and Henson should
construct a large model out of their own funds. On Henson’s suggestion
Colombine and Marriott were bought out as regards the original patent,
and Stringfellow and Henson entered into an agreement and set to work.
Their work is briefly described in a little pamphlet by F. J.
Stringfellow, entitled _A few Remarks on what has been done with
screw-propelled Aeroplane Machines from 1809 to 1892_. The author
writes with regard to the work that his father and Henson undertook:--
‘They commenced the construction of a small model operated by a spring,
and laid down the larger model 20 ft. from tip to tip of planes, 3½ ft.
wide, giving 70 ft. of sustaining surface, about 10 more in the tail.
The making of this model required great consideration; various supports
for the wings were tried, so as to combine lightness with firmness,
strength and rigidity.
‘The planes were staid from three sets of fish-shaped masts, and rigged
square and firm by flat steel rigging. The engine and boiler were
put in the car to drive two screw-propellers, right and left-handed,
3 ft. in diameter, with four blades each, occupying three-quarters
of the area of the circumference, set at an angle of 60 degrees. A
considerable time was spent in perfecting the motive power. Compressed
air was tried and abandoned. Tappets, cams, and eccentrics were all
tried, to work the slide valve, to obtain the best results. The piston
rod of engine passed through both ends of the cylinder, and with long
connecting rods worked direct on the crank of the propellers. From
memorandum of experiments still preserved the following is a copy of
one: June, 27th, 1845, water 50 ozs., spirit 10 ozs., lamp lit 8.45,
gauge moves 8.46, engine started 8.48 (100 lb. pressure), engine
stopped 8.57, worked 9 minutes, 2,288 revolutions, average 254 per
minute. No priming, 40 ozs. water consumed, propulsion (thrust of
propellers), 5 lbs. 4½ ozs. at commencement, steady, 4 lbs. ½ oz., 57
revolutions to 1 oz. water, steam cut off one-third from beginning.
‘The diameter of cylinder of engine was 1½ inch, length of stroke 3
inches.
‘In the meantime an engine was also made for the smaller model, and a
wing action tried, but with poor results. The time was mostly devoted
to the larger model, and in 1847 a tent was erected on Bala Down,
about two miles from Chard, and the model taken up one night by the
workmen. The experiments were not so favourable as was expected. The
machine could not support itself for any distance, but, when launched
off, gradually descended, although the power and surface should have
been ample; indeed, according to latest calculations, the thrust should
have carried more than three times the weight, for there was a thrust
of 5 lbs. from the propellers, and a surface of over 70 square feet to
sustain under 30 lbs., but necessary speed was lacking.’
[Illustration: Stringfellow’s model triplane, 1868.]
Stringfellow himself explained the failure as follows:--
‘There stood our aerial protégée in all her purity--too delicate,
too fragile, too beautiful for this rough world; at least those were
my ideas at the time, but little did I think how soon it was to be
realised. I soon found, before I had time to introduce the spark, a
drooping in the wings, a flagging in all the parts. In less than ten
minutes the machine was saturated with wet from a deposit of dew, so
that anything like a trial was impossible by night. I did not consider
we could get the silk tight and rigid enough. Indeed, the framework
altogether was too weak. The steam-engine was the best part. Our
want of success was not for want of power or sustaining surface, but
for want of proper adaptation of the means to the end of the various
parts.’
Henson, who had spent a considerable amount of money in these
experimental constructions, consoled himself for failure by venturing
into matrimony; in 1849 he went to America, leaving Stringfellow to
continue experimenting alone. From 1846 to 1848 Stringfellow worked on
what is really an epoch-making item in the history of aeronautics--the
first engine-driven aeroplane which actually flew. The machine in
question had a 10 foot span, and was 2 ft. across in the widest part
of the wing; the length of tail was 3 ft. 6 ins., and the span of tail
in the widest part 22 ins., the total sustaining area being about 14
sq. ft. The motive power consisted of an engine with a cylinder of
three-quarter inch diameter and a two-inch stroke; between this and
the crank shaft was a bevelled gear giving three revolutions of the
propellers to every stroke of the engine; the propellers, right and
left screw, were four-bladed and 16 inches in diameter. The total
weight of the model with engine was 8 lbs. Its successful flight is
ascribed to the fact that Stringfellow curved the wings, giving them
rigid front edges and flexible trailing edges, as suggested long before
both by Da Vinci and Borelli, but never before put into practice.
Mr F. J. Stringfellow, in the pamphlet quoted above, gives the best
account of the flight of this model: ‘My father had constructed another
small model which was finished early in 1848, and having the loan of
a long room in a disused lace factory, early in June the small model
was moved there for experiments. The room was about 22 yards long and
from 10 to 12 ft. high.... The inclined wire for starting the machine
occupied less than half the length of the room and left space at the
end for the machine to clear the floor. In the first experiment the
tail was set at too high an angle, and the machine rose too rapidly on
leaving the wire. After going a few yards it slid back as if coming
down an inclined plane, at such an angle that the point of the tail
struck the ground and was broken. The tail was repaired and set at a
smaller angle. The steam was again got up, and the machine started
down the wire, and, upon reaching the point of self-detachment, it
gradually rose until it reached the farther end of the room, striking a
hole in the canvas placed to stop it. In experiments the machine flew
well, when rising as much as one in seven. The late Rev. J. Riste,
Esq., lace manufacturer, Northcote Spicer, Esq., J. Toms, Esq., and
others witnessed experiments. Mr Marriatt, late of the San Francisco
_News Letter_ brought down from London Mr Ellis, the then lessee of
Cremorne Gardens, Mr Partridge, and Lieutenant Gale, the aeronaut, to
witness experiments. Mr Ellis offered to construct a covered way at
Cremorne for experiments. Mr Stringfellow repaired to Cremorne, but not
much better accommodations than he had at home were provided, owing
to unfulfilled engagement as to room. Mr Stringfellow was preparing
for departure when a party of gentlemen unconnected with the Gardens
begged to see an experiment, and finding them able to appreciate his
endeavours, he got up steam and started the model down the wire. When
it arrived at the spot where it should leave the wire it appeared to
meet with some obstruction, and threatened to come to the ground, but
it soon recovered itself and darted off in as fair a flight as it was
possible to make at a distance of about 40 yards, where it was stopped
by the canvas.
‘Having now demonstrated the practicability of making a steam-engine
fly, and finding nothing but a pecuniary loss and little honour,
this experimenter rested for a long time, satisfied with what he had
effected. The subject, however, had to him special charms, and he still
contemplated the renewal of his experiments.’
It appears that Stringfellow’s interest did not revive sufficiently
for the continuance of the experiments until the founding of the
Aeronautical Society of Great Britain in 1866. Wenham’s paper on Aerial
Locomotion read at the first meeting of the Society, which was held
at the Society of Arts under the Presidency of the Duke of Argyll,
was the means of bringing Stringfellow back into the field. It was
Wenham’s suggestion, in the first place, that monoplane design should
be abandoned for the superposition of planes; acting on this suggestion
Stringfellow constructed a model triplane, and also designed a steam
engine of slightly over one horse-power, and a one horse-power copper
boiler and fire box which, although capable of sustaining a pressure of
500 lbs. to the square inch, weighed only about 40 lbs.
Both the engine and the triplane model were exhibited at the first
Aeronautical Exhibition held at the Crystal Palace in 1868. The
triplane had a supporting surface of 28 sq. ft.; inclusive of engine,
boiler, fuel, and water its total weight was under 12 lbs. The engine
worked two 21 in. propellers at 600 revolutions per minute, and
developed 100 lbs. steam pressure in five minutes, yielding one-third
horse-power. Since no free flight was allowed in the Exhibition, owing
to danger from fire, the triplane was suspended from a wire in the
nave of the building, and it was noted that, when running along the
wire, the model made a perceptible lift.
A prize of £100 was awarded to the steam engine as the lightest steam
engine in proportion to its power. The engine and model together may
be reckoned as Stringfellow’s best achievement. He used his £100 in
preparation for further experiments, but he was now an old man, and
his work was practically done. Both the triplane and the engine were
eventually bought for the Washington Museum; Stringfellow’s earlier
models, together with those constructed by him in conjunction with
Henson, remain in this country in the Victoria and Albert Museum.
John Stringfellow died on December 13th, 1883. His place in the history
of aeronautics is at least equal to that of Cayley, and it may be
said that he laid the foundation of such work as was subsequently
accomplished by Maxim, Langley, and their fellows. It was the coming
of the internal combustion engine that rendered flight practicable,
and had this prime mover been available in John Stringfellow’s day
the Wright brothers’ achievement might have been antedated by half a
century.
V
WENHAM, LE BRIS, AND SOME OTHERS
There are few outstanding events in the development of aeronautics
between Stringfellow’s final achievement and the work of such men as
Lilienthal, Pilcher, Montgomery, and their kind; in spite of this, the
later middle decades of the nineteenth century witnessed a considerable
amount of spade work both in England and in France, the two countries
which led in the way in aeronautical development until Lilienthal gave
honour to Germany, and Langley and Montgomery paved the way for the
Wright Brothers in America.
Two abortive attempts characterised the sixties of last century in
France. As regards the first of these, it was carried out by three
men, Nadar, Ponton d’Amecourt, and De la Landelle, who conceived the
idea of a full-sized helicopter machine. D’Amecourt exhibited a steam
model, constructed in 1865, at the Aeronautical Society’s Exhibition in
1868. The engine was aluminium with cylinders of bronze, driving two
screws placed one above the other and rotating in opposite directions,
but the power was not sufficient to lift the model. De la Landelle’s
principal achievement consisted in the publication in 1863 of a book
entitled _Aviation_, which has a certain historical value; he got out
several designs for large machines on the helicopter principle, but did
little more until the three combined in the attempt to raise funds
for the construction of their full-sized machine. Since the funds were
not forthcoming, Nadar took to ballooning as the means of raising
money; apparently he found this substitute for real flight sufficiently
interesting to divert him from the study of the helicopter principle,
for the experiment went no further.
The other experimenter of this period, one Count d’Esterno, took out a
patent in 1864 for a soaring machine which allowed for alteration of
the angle of incidence of the wings in the manner that was subsequently
carried out by the Wright Brothers. It was not until 1883 that any
attempt was made to put this patent to practical use, and, as the
inventor died while it was under construction, it was never completed.
D’Esterno was also responsible for the production of a work entitled
_Du Vol des Oiseaux_, which is a very remarkable study of the flight of
birds.
Mention has already been made of the founding of the Aeronautical
Society of Great Britain, which, since 1918, has been the Royal
Aeronautical Society. 1866 witnessed the first meeting of the Society
under the Presidency of the Duke of Argyll, when in June, at the
Society of Arts, Francis Herbert Wenham read his now classic paper
_Aerial Locomotion_. Certain quotations from this will show how clearly
Wenham had thought out the problems connected with flight.
‘The first subject for consideration is the proportion of surface
to weight, and their combined effect in descending perpendicularly
through the atmosphere. The datum is here based upon the consideration
of safety, for it may sometimes be needful for a living being to drop
passively, without muscular effort. One square foot of sustaining
surface for every pound of the total weight will be sufficient for
security.
‘According to Smeaton’s table of atmospheric resistances, to produce
a force of one pound on a square foot, the wind must move against the
plane (or which is the same thing, the plane against the wind), at the
rate of twenty-two feet per second, or 1,320 feet per minute, equal to
fifteen miles per hour. The resistance of the air will now balance the
weight on the descending surface, and, consequently, it cannot exceed
that speed. Now, twenty-two feet per second is the velocity acquired at
the end of a fall of eight feet--a height from which a well-knit man or
animal may leap down without much risk of injury. Therefore, if a man
with parachute weigh together 143 lbs., spreading the same number of
square feet of surface contained in a circle fourteen and a half feet
in diameter, he will descend at perhaps an unpleasant velocity, but
with safety to life and limb.
‘It is a remarkable fact how this proportion of wing-surface to
weight extends throughout a great variety of the flying portion of
the animal kingdom, even down to hornets, bees, and other insects.
In some instances, however, as in the gallinaceous tribe, including
pheasants, this area is somewhat exceeded, but they are known to be
very poor fliers. Residing as they do chiefly on the ground, their
wings are only required for short distances, or for raising them or
easing their descent from their roosting-places in forest trees, the
shortness of their wings preventing them from taking extended flights.
The wing-surface of the common swallow is rather more than in the ratio
of two square feet per pound, but having also great length of pinion,
it is both swift and enduring in its flight. When on a rapid course
this bird is in the habit of furling its wings into a narrow compass.
The greater extent of surface is probably needful for the continual
variations of speed and instant stoppages for obtaining its insect food.
‘On the other hand, there are some birds, particularly of the duck
tribe, whose wing-surface but little exceeds half a square foot,
or seventy-two inches per pound, yet they may be classed among the
strongest and swiftest of fliers. A weight of one pound, suspended
from an area of this extent, would acquire a velocity due to a fall of
sixteen feet--a height sufficient for the destruction or injury of most
animals. But when the plane is urged forward horizontally, in a manner
analogous to the wings of a bird during flight, the sustaining power is
greatly influenced by the form and arrangement of the surface.
‘In the case of perpendicular descent, as a parachute, the sustaining
effect will be much the same, whatever the figure of the outline of the
superficies may be, and a circle perhaps affords the best resistance of
any. Take, for example, a circle of twenty square feet (as possessed
by the pelican) loaded with as many pounds. This, as just stated, will
limit the rate of perpendicular descent to 1,320 feet per minute.
But instead of a circle sixty-one inches in diameter, if the area is
bounded by a parallelogram ten feet long by two feet broad, and whilst
at perfect freedom to descend perpendicularly, let a force be applied
exactly in a horizontal direction, so as to carry it edgeways, with the
long side foremost, at a forward speed of thirty miles per hour--just
double that of its passive descent: the rate of fall under these
conditions will be decreased most remarkably, probably to less than
one-fifteenth part, or eighty-eight feet per minute, or one mile per
hour.’
And again: ‘It has before been shown how utterly inadequate the mere
perpendicular impulse of a plane is found to be in supporting a weight,
when there is no horizontal motion at the time. There is no material
weight of air to be acted upon, and it yields to the slightest force,
however great the velocity of impulse may be. On the other hand,
suppose that a large bird, in full flight, can make forty miles per
hour, or 3,520 feet per minute, and performs one stroke per second.
Now, during every fractional portion of that stroke, the wing is
acting upon and obtaining an impulse from a fresh and undisturbed body
of air; and if the vibration of the wing is limited to an arc of two
feet, this by no means represents the small force of action that would
be obtained when in a stationary position, for the impulse is secured
upon a stratum of fifty-eight feet in length of air at each stroke. So
that the conditions of weight of air for obtaining support equally well
apply to weight of air and its reaction in producing forward impulse.
‘So necessary is the acquirement of this horizontal speed, even in
commencing flight, that most heavy birds, when possible, rise against
the wind, and even run at the top of their speed to make their
wings available, as in the example of the eagle, mentioned at the
commencement of this paper. It is stated that the Arabs, on horseback,
can approach near enough to spear these birds, when on the plain,
before they are able to rise; their habit is to perch on an eminence,
where possible.
‘The tail of a bird is not necessary for flight. A pigeon can fly
perfectly with this appendage cut short off; it probably performs an
important function in steering, for it is to be remarked, that most
birds that have either to pursue or evade pursuit are amply provided
with this organ.
‘The foregoing reasoning is based upon facts, which tend to show
that the flight of the largest and heaviest of all birds is really
performed with but a small amount of force, and that man is endowed
with sufficient muscular power to enable him also to take individual
and extended flights, and that success is probably only involved in
a question of suitable mechanical adaptations. But if the wings are
to be modelled in imitation of natural examples, but very little
consideration will serve to demonstrate its utter impracticability when
applied in these forms.’
Thus Wenham, one of the best theorists of his age. The Society with
which this paper connects his name has done work, between that time
and the present, of which the importance cannot be overestimated, and
has been of the greatest value in the development of aeronautics,
both in theory and experiment. The objects of the Society are to give
a stronger impulse to the scientific study of aerial navigation, to
promote the intercourse of those interested in the subject at home
and abroad, and to give advice and instruction to those who study the
principles upon which aeronautical science is based. From the date of
its foundation the Society has given special study to dynamic flight,
putting this before ballooning. Its library, its bureau of advice and
information, and its meetings, all assist in forwarding the study
of aeronautics, and its twenty-three early _Annual Reports_ are of
considerable value, containing as they do a large amount of useful
information on aeronautical subjects, and forming practically the basis
of aeronautical science.
Ante to Wenham, Stringfellow and the French experimenters already
noted, by some years, was Le Bris, a French sea captain, who appears
to have required only a thorough scientific training to have rendered
him of equal moment in the history of gliding flight with Lilienthal
himself. Le Bris, it appears, watched the albatross and deduced, from
the manner in which it supported itself in the air, that plane surfaces
could be constructed and arranged to support a man in like manner.
Octave Chanute, himself a leading exponent of gliding, gives the best
description of Le Bris’s experiments in a work, _Progress in Flying
Machines_, which, although published as recently as 1894, is already
rare. Chanute draws from a still rarer book, namely, De la Landelle’s
work published in 1884. Le Bris himself, quoted by De la Landelle as
speaking of his first visioning of human flight, describes how he
killed an albatross, and then--‘I took the wing of the albatross and
exposed it to the breeze; and lo! in spite of me it drew forward into
the wind; notwithstanding my resistance it tended to rise. Thus I had
discovered the secret of the bird! I comprehended the whole mystery of
flight.’
This apparently took place while at sea; later on Le Bris, returning to
France, designed and constructed an artificial albatross of sufficient
size to bear his own weight. The fact that he followed the bird outline
as closely as he did attests his lack of scientific training for his
task, while at the same time the success of the experiment was proof
of his genius. The body of his artificial bird, boat-shaped, was 13½
ft. in length, with a breadth of 4 ft. at the widest part. The material
was cloth stretched over a wooden framework; in front was a small mast
rigged after the manner of a ship’s masts to which were attached poles
and cords with which Le Bris intended to work the wings. Each wing
was 23 ft. in length, giving a total supporting surface of nearly 220
sq. ft.; the weight of the whole apparatus was only 92 pounds. For
steering, both vertical and horizontal, a hinged tail was provided,
and the leading edge of each wing was made flexible. In construction
throughout, and especially in that of the wings, Le Bris adhered as
closely as possible to the original albatross.
He designed an ingenious kind of mechanism which he termed ‘Rotules,’
which by means of two levers gave a rotary motion to the front edge
of the wings, and also permitted of their adjustment to various
angles. The inventor’s idea was to stand upright in the body of the
contrivance, working the levers and cords with his hands, and with his
feet on a pedal by means of which the steering tail was to be worked.
He anticipated that, given a strong wind, he could rise into the air
after the manner of an albatross, without any need for flapping his
wings, and the account of his first experiment forms one of the most
interesting incidents in the history of flight. It is related in full
in Chanute’s work, from which the present account is summarised.
Le Bris made his first experiment on a main road near Douarnenez, at
Trefeuntec. From his observation of the albatross Le Bris concluded
that it was necessary to get some initial velocity in order to make the
machine rise; consequently on a Sunday morning, with a breeze of about
12 miles an hour blowing down the road, he had his albatross placed on
a cart and set off, with a peasant driver, against the wind. At the
outset the machine was fastened to the cart by a rope running through
the rails on which the machine rested, and secured by a slip knot on
Le Bris’s own wrist, so that only a jerk on his part was necessary
to loosen the rope and set the machine free. On each side walked an
assistant holding the wings, and when a turn of the road brought the
machine full into the wind these men were instructed to let go, while
the driver increased the pace from a walk to a trot. Le Bris, by
pressure on the levers of the machine, raised the front edges of his
wings slightly; they took the wind almost instantly to such an extent
that the horse, relieved of a great part of the weight he had been
drawing, turned his trot into a gallop. Le Bris gave the jerk of the
rope that should have unfastened the slip knot, but a concealed nail
on the cart caught the rope, so that it failed to run. The lift of the
machine was such, however, that it relieved the horse of very nearly
the weight of the cart and driver, as well as that of Le Bris and his
machine, and in the end the rails of the cart gave way. Le Bris rose in
the air, the machine maintaining perfect balance and rising to a height
of nearly 300 ft., the total length of the glide being upwards of an
eighth of a mile. But at the last moment the rope which had originally
fastened the machine to the cart got wound round the driver’s body, so
that this unfortunate dangled in the air under Le Bris and probably
assisted in maintaining the balance of the artificial albatross. Le
Bris, congratulating himself on his success, was prepared to enjoy just
as long a time in the air as the pressure of the wind would permit,
but the howls of the unfortunate driver at the end of the rope beneath
him dispelled his dreams; by working his levers he altered the angle of
the front wing edges so skilfully as to make a very successful landing
indeed for the driver, who, entirely uninjured, disentangled himself
from the rope as soon as he touched the ground, and ran off to retrieve
his horse and cart.
Apparently his release made a difference in the centre of gravity, for
Le Bris could not manipulate his levers for further ascent; by skilful
manipulation he retarded the descent sufficiently to escape injury to
himself; the machine descended at an angle, so that one wing, striking
the ground in front of the other, received a certain amount of damage.
It may have been on account of the reluctance of this same or another
driver that Le Bris chose a different method of launching himself in
making a second experiment with his albatross. He chose the edge of a
quarry which had been excavated in a depression of the ground; here
he assembled his apparatus at the bottom of the quarry, and by means
of a rope was hoisted to a height of nearly 100 ft. from the quarry
bottom, this rope being attached to a mast which he had erected upon
the edge of the depression in which the quarry was situated. Thus
hoisted, the albatross was swung to face a strong breeze that blew
inland, and Le Bris manipulated his levers to give the front edges of
his wings a downward angle, so that only the top surfaces should take
the wing pressure. Having got his balance, he obtained a lifting angle
of incidence on the wings by means of his levers, and released the hook
that secured the machine, gliding off over the quarry. On the glide
he met with the inevitable upward current of air that the quarry and
the depression in which it was situated caused; this current upset
the balance of the machine and flung it to the bottom of the quarry,
breaking it to fragments. Le Bris, apparently as intrepid as ingenious,
gripped the mast from which his levers were worked, and, springing
upward as the machine touched earth, escaped with no more damage than
a broken leg. But for the rebound of the levers he would have escaped
even this.
The interest of these experiments is enhanced by the fact that Le
Bris was a seafaring man who conducted them from love of the science
which had fired his imagination, and in so doing exhausted his own
small means. It was in 1855 that he made these initial attempts, and
twelve years passed before his persistence was rewarded by a public
subscription made at Brest for the purpose of enabling him to continue
his experiments. He built a second albatross, and on the advice of his
friends ballasted it for flight instead of travelling in it himself.
It was not so successful as the first, probably owing to the lack of
human control while in flight; on one of the trials a height of 150 ft.
was attained, the glider being secured by a thin rope and held so as
to face into the wind. A glide of nearly an eighth of a mile was made
with the rope hanging slack, and, at the end of this distance, a rise
in the ground modified the force of the wind, whereupon the machine
settled down without damage. A further trial in a gusty wind resulted
in the complete destruction of this second machine; Le Bris had no
more funds, no further subscriptions were likely to materialise, and
so the experiments of this first exponent of the art of gliding (save
for Besnier and his kind) came to an end. They constituted a notable
achievement, and undoubtedly Le Bris deserves a better place than has
been accorded him in the ranks of the early experimenters.
Contemporary with him was Charles Spencer, the first man to practise
gliding in England. His apparatus consisted of a pair of wings with
a total area of 30 sq. ft., to which a tail and body were attached.
The weight of this apparatus was some 24 lbs., and, launching himself
on it from a small eminence, as was done later by Lilienthal in his
experiments, the inventor made flights of over 120 feet. The glider in
question was exhibited at the Aeronautical Exhibition of 1868.
VI
THE AGE OF THE GIANTS
Until the Wright Brothers definitely solved the problem of flight and
virtually gave the aeroplane its present place in aeronautics, there
were three definite schools of experiment. The first of these was
that which sought to imitate nature by means of the ornithopter or
flapping-wing machines directly imitative of bird flight; the second
school was that which believed in the helicopter or lifting screw; the
third and eventually successful school is that which followed up the
principle enunciated by Cayley, that of opposing a plane surface to the
resistance of the air by supplying suitable motive power to drive it at
the requisite angle for support.
Engineering problems generally go to prove that too close an imitation
of nature in her forms of reciprocating motion is not advantageous;
it is impossible to copy the minutiae of a bird’s wing effectively,
and the bird in flight depends on the tiniest details of its feathers
just as much as on the general principle on which the whole wing is
constructed. Bird flight, however, has attracted many experimenters,
including even Lilienthal; among others may be mentioned F. W. Brearey,
who invented what he called the ‘Pectoral cord,’ which stored energy
on each upstroke of the artificial wing; E. P. Frost; Major R. Moore,
and especially Hureau de Villeneuve, a most enthusiastic student
of this form of flight, who began his experiments about 1865, and
altogether designed and made nearly 300 artificial birds. One of his
later constructions was a machine in bird form with a wing span of
about 50 ft.; the motive power for this was supplied by steam from a
boiler which, being stationary on the ground, was connected by a length
of hose to the machine. De Villeneuve, turning on steam for his first
trial, obtained sufficient power to make the wings beat very forcibly;
with the inventor on the machine the latter rose several feet into the
air, whereupon de Villeneuve grew nervous and turned off the steam
supply. The machine fell to the earth, breaking one of its wings, and
it does not appear that de Villeneuve troubled to reconstruct it. This
experiment remains as the greatest success yet achieved by any machine
constructed on the ornithopter principle.
It may be that, as forecasted by the prophet Wells, the flapping-wing
machine will yet come to its own and compete with the aeroplane in
efficiency. Against this, however, are the practical advantages of
the rotary mechanism of the aeroplane propeller as compared with the
movement of a bird’s wing, which, according to Marey, moves in a figure
of eight. The force derived from a propeller is of necessity continual,
while it is equally obvious that that derived from a flapping movement
is intermittent, and, in the recovery of a wing after completion of one
stroke for the next, there is necessarily a certain cessation, if not
loss, of power.
The matter of experiment along any lines in connection with aviation is
primarily one of hard cash. Throughout the whole history of flight up
to the outbreak of the European war development has been handicapped
on the score of finance, and, since the arrival of the aeroplane,
both ornithopter and helicopter schools have been handicapped by
this consideration. Thus serious study of the efficiency of wings in
imitation of those of the living bird has not been carried to a point
that might win success for this method of propulsion. Even Wilbur
Wright studied this subject and propounded certain theories, while
a later and possibly more scientific student, F. W. Lanchester, has
also contributed empirical conclusions. Another and earlier student
was Lawrence Hargrave, who made a wing-propelled model which achieved
successful flight, and in 1885 was exhibited before the Royal Society
of New South Wales. Hargrave called the principle on which his
propeller worked that of a ‘Trochoided plane’; it was, in effect,
similar to the feathering of an oar.
Hargrave, to diverge for a brief while from the machine to the man,
was one who, although he achieved nothing worthy of special remark,
contributed a great deal of painstaking work to the science of flight.
He made a series of experiments with man-lifting kites in addition to
making a study of flapping-wing flight. It cannot be said that he set
forth any new principle; his work was mainly imitative, but at the
same time by developing ideas originated in great measure by others he
helped toward the solution of the problem.
Attempts at flight on the helicopter principle consist in the work of
De la Landelle and others already mentioned. The possibility of flight
by this method is modified by a very definite disadvantage of which
lovers of the helicopter seem to take little account. It is always
claimed for a machine of this type that it possesses great advantages
both in rising and in landing, since, if it were effective, it would
obviously be able to rise from and alight on any ground capable of
containing its own bulk; a further advantage claimed is that the
helicopter would be able to remain stationary in the air, maintaining
itself in any position by the vertical lift of its propeller.
These potential assets do not take into consideration the fact that
efficiency is required not only in rising, landing, and remaining
stationary in the air, but also in actual flight. It must be evident
that if a certain amount of the motive force is used in maintaining the
machine off the ground, that amount of force is missing from the total
of horizontal driving power. Again, it is often assumed by advocates
of this form of flight that the rapidity of climb of the helicopter
would be far greater than that of the driven plane; this view overlooks
the fact that the maintenance of aerodynamic support would claim the
greater part of the engine-power; the rate of ascent would be governed
by the amount of power that could be developed surplus to that required
for maintenance.
This is best explained by actual figures: assuming that a propeller 15
ft. in diameter is used, almost 50 horse-power would be required to get
an upward lift of 1,000 pounds; this amount of horse-power would be
continually absorbed in maintaining the machine in the air at any given
level; for actual lift from one level to another at a speed of eleven
feet per second a further 20 horse-power would be required, which means
that 70 horse-power must be constantly provided for; this absorption
of power in the mere maintenance of aerodynamic support is a permanent
drawback.
The attraction of the helicopter lies, probably, in the ease with
which flight is demonstrated by means of models constructed on this
principle, but one truism with regard to the principles of flight
is that the problems change remarkably, and often unexpectedly,
with the size of the machine constructed for experiment. Berriman,
in a brief but very interesting manual entitled _Principles of
Flight_, assumed that ‘there is a significant dimension of which
the effective area is an expression of the second power, while the
weight became an expression of the third power. Then once again we
have the two-thirds power law militating against the successful
construction of large helicopters, on the ground that the essential
weight increases disproportionately fast to the effective area. From a
consideration of the structural features of propellers it is evident
that this particular relationship does not apply in practice, but it
seems reasonable that some such governing factor should exist as an
explanation of the apparent failure of all full-sized machines that
have been constructed. Among models there is nothing more strikingly
successful than the toy helicopter, in which the essential weight is so
small compared with the effective area.’
De la Landelle’s work, already mentioned, was carried on a few years
later by another Frenchman, Castel, who constructed a machine with
eight propellers arranged in two fours and driven by a compressed
air motor or engine. The model with which Castel experimented had a
total weight of only 49 lbs.; it rose in the air and smashed itself
by driving against a wall, and the inventor does not seem to have
proceeded further. Contemporary with Castel was Professor Forlanini,
whose design was for a machine very similar to de la Landelle’s,
with two superposed screws. This machine ranks as the second on the
helicopter principle to achieve flight; it remained in the air for no
less than the third of a minute in one of its trials.
Later experimenters in this direction were Kress, a German; Professor
Wellner, an Austrian; and W. R. Kimball, an American. Kress, like most
Germans, set to the development of an idea which others had originated;
he followed de la Landelle and Forlanini by fitting two superposed
propellers revolving in opposite directions, and with this machine he
achieved good results as regards horse-power to weight; Kimball, it
appears, did not get beyond the rubber-driven model stage, and any
success he may have achieved was modified by the theory enunciated by
Berriman and quoted above.
Comparing these two schools of thought, the helicopter and bird-flight
schools, it appears that the latter has the greater chance of eventual
success--that is, if either should ever come into competition with the
aeroplane as effective means of flight. So far, the aeroplane holds
the field, but the whole science of flight is so new and so full of
unexpected developments that this is no reason for assuming that other
means may not give equal effect, when money and brains are diverted
from the driven plane to a closer imitation of natural flight.
Reverting from non-success to success, from consideration of the two
methods mentioned above to the direction in which practical flight
has been achieved, it is to be noted that between the time of Le
Bris, Stringfellow, and their contemporaries, and the nineties of
last century, there was much plodding work carried out with little
visible result, more especially so far as English students were
concerned. Among the incidents of those years is one of the most
pathetic tragedies in the whole history of aviation, that of Alphonse
Penaud, who, in his thirty years of life, condensed the experience of
his predecessors and combined it with his own genius to state in a
published patent what the aeroplane of to-day should be. Consider the
following abstract of Penaud’s design as published in his patent of
1876, and comparison of this with the aeroplane that now exists will
show very few divergences except for those forced on the inventor by
the fact that the internal combustion engine had not then developed.
The double-surfaced planes were to be built with wooden ribs and
arranged with a slight dihedral angle; there was to be a large aspect
ratio and the wings were cambered as in Stringfellow’s later models.
Provision was made for warping the wings while in flight, and the
trailing edges were so designed as to be capable of upward twist while
the machine was in the air. The planes were to be placed above the car,
and provision was even made for a glass wind-screen to give protection
to the pilot during flight. Steering was to be accomplished by means
of lateral and vertical planes forming a tail; these controlled by a
single lever corresponding to the ‘joy stick’ of the present day plane.
Penaud conceived this machine as driven by two propellers;
alternatively these could be driven by petrol or steam-fed motor,
and the centre of gravity of the machine while in flight was in the
front fifth of the wings. Penaud estimated from 20 to 30 horse-power
sufficient to drive this machine, weighing with pilot and passenger
2,600 lbs., through the air at a speed of 60 miles an hour, with the
wings set at an angle of incidence of two degrees. So complete was the
design that it even included instruments, consisting of an aneroid,
pressure indicator, an anemometer, a compass, and a level. There,
with few alterations, is the aeroplane as we know it--and Penaud was
twenty-seven when his patent was published.
For three years longer he worked, experimenting with models,
contributing essays and other valuable data to French papers on the
subject of aeronautics. His gains were ill health, poverty, and
neglect, and at the age of thirty a pistol shot put an end to what had
promised to be one of the most brilliant careers in all the history of
flight.
Two years before the publication of Penaud’s patent Thomas Moy
experimented at the Crystal Palace with a twin-propelled aeroplane,
steam driven, which seems to have failed mainly because the internal
combustion engine had not yet come to give sufficient power for
weight. Moy anchored his machine to a pole running on a prepared
circular track; his engine weighed 80 lbs. and, developing only three
horse-power, gave him a speed of 12 miles an hour. He himself estimated
that the machine would not rise until he could get a speed of 35 miles
an hour, and his estimate was correct. Two six-bladed propellers were
placed side by side between the two main planes of the machine, which
was supported on a triangular wheeled undercarriage and steered by
fairly conventional tail planes. Moy realised that he could not get
sufficient power to achieve flight, but he went on experimenting in
various directions, and left much data concerning his experiments which
has not yet been deemed worthy of publication, but which still contains
a mass of information that is of practical utility, embodying as it
does a vast amount of painstaking work.
Penaud and Moy were followed by Goupil, a Frenchman, who, in place of
attempting to fit a motor to an aeroplane, experimented by making the
wind his motor. He anchored his machine to the ground, allowing it two
feet of lift, and merely waited for a wind to come along and lift it.
The machine was stream lined, and the wings, curving as in the early
German patterns of war aeroplanes, gave a total lifting surface of
about 290 sq. ft. Anchored to the ground and facing a wind of 19 feet
per second, Goupil’s machine lifted its own weight and that of two men
as well to the limit of its anchorage. Although this took place as late
as 1883 the inventor went no further in practical work. He published
a book, however, entitled _La Locomotion Aérienne_, which is still of
great importance, more especially on the subject of inherent stability.
In 1884 came the first patents of Horatio Phillips, whose work lay
mainly in the direction of investigation into the curvature of plane
surfaces, with a view to obtaining the greatest amount of support.
Phillips was one of the first to treat the problem of curvature of
planes as a matter for scientific experiment, and, great as has been
the development of the driven plane in the 36 years that have passed
since he began, there is still room for investigation into the subject
which he studied so persistently and with such valuable result.
At this point it may be noted that, with the solitary exception of
Le Bris, practically every student of flight had so far set about
constructing the means of launching humanity into the air without any
attempt at ascertaining the nature and peculiarities of the sustaining
medium. The attitude of experimenters in general might be compared to
that of a man who from boyhood had grown up away from open water, and,
at the first sight of an expanse of water, set to work to construct a
boat with a vague idea that, since wood would float, only sufficient
power was required to make him an efficient navigator. Accident,
perhaps, in the shape of lack of means of procuring driving power,
drove Le Bris to the form of experiment which he actually carried out;
it remained for the later years of the nineteenth century to produce
men who were content to ascertain the nature of the support the air
would afford before attempting to drive themselves through it.
Of the age in which these men lived and worked, giving their all in
many cases to the science they loved, even to life itself, it may be
said with truth that ‘there were giants on the earth in those days,’ as
far as aeronautics is in question. It was an age of giants who lived
and dared and died, venturing into uncharted space, knowing nothing
of its dangers, giving, as a man gives to his mistress, without stint
and for the joy of the giving. The science of to-day, compared with
the glimmerings that were in that age of the giants, is a fixed and
certain thing; the problems of to-day are minor problems, for the great
major problem vanished in solution when the Wright Brothers made their
first ascent. In that age of the giants was evolved the flying man,
the new type in human species which found full expression and came to
full development in the days of the war, achieving feats of daring and
endurance which leave the commonplace landsman staggered at thought of
that of which his fellows prove themselves capable. He is a new type,
this flying man, a being of self-forgetfulness; of such was Lilienthal,
of such was Pilcher; of such in later days were Farman, Bleriot, Hamel,
Rolls, and their fellows; great names that will live for as long as
man flies, adventurers equally with those of the spacious days of
Elizabeth. To each of these came the call, and he worked and dared and
passed, having, perhaps, advanced one little step in the long march
that has led toward the perfecting of flight.
It is not yet twenty years since man first flew, but into that twenty
years have been compressed a century or so of progress, while, in
the two decades that preceded it, was compressed still more. We have
only to recall and recount the work of four men: Lilienthal, Langley,
Pilcher, and Clement Ader to see the immense stride that was made
between the time when Penaud pulled a trigger for the last time and
the Wright Brothers first left the earth. Into those two decades was
compressed the investigation that meant knowledge of the qualities of
the air, together with the development of the one prime mover that
rendered flight a possibility--the internal combustion engine. The
coming and progress of this latter is a thing apart, to be detailed
separately; for the present we are concerned with the evolution of
the driven plane, and with it the evolution of that daring being, the
flying man. The two are inseparable, for the men gave themselves to
their art; the story of Lilienthal’s life and death is the story of his
work; the story of Pilcher’s work is that of his life and death.
Considering the flying man as he appeared in the war period, there
entered into his composition a new element--patriotism--which brought
about a modification of the type, or, perhaps, made it appear that
certain men belonged to the type who in reality were commonplace
mortals, animated, under normal conditions, by normal motives, but
driven by the stress of the time to take rank with the last expression
of human energy, the flying type. However that may be, what may be
termed the mathematising of aeronautics has rendered the type itself
evanescent; your pilot of to-day knows his craft, once he is trained,
much in the manner that a driver of a motor-lorry knows his vehicle;
design has been systematised, capabilities have been tabulated; camber,
dihedral angle, aspect ratio, engine power, and plane surface, are
business items of drawing office and machine shop; there is room for
enterprise, for genius, and for skill; once and again there is room for
daring, as in the first Atlantic flight. Yet that again was a thing of
mathematical calculation and petrol storage, allied to a certain stark
courage which may be found even in landsmen. For the ventures into the
unknown, the limit of daring, the work for work’s sake, with the almost
certainty that the final reward was death, we must look back to the age
of the giants, the age when flying was not a business, but romance.
[Illustration: Lilienthal with his glider folded after a glide.]
[Illustration: Lilienthal’s biplane glider alighting.]
[Illustration: Pilcher’s ‘Bat.’]
[Illustration: The ‘Bat’, side view.]
VII
LILIENTHAL AND PILCHER
There was never a more enthusiastic and consistent student of the
problems of flight than Otto Lilienthal, who was born in 1848 at
Anklam, Pomerania, and even from his early school-days dreamed and
planned the conquest of the air. His practical experiments began when,
at the age of thirteen, he and his brother Gustav made wings consisting
of wooden framework covered with linen, which Otto attached to his
arms, and then ran downhill flapping them. In consequence of possible
derision on the part of other boys, Otto confined these experiments
for the most part to moonlit nights, and gained from them some idea
of the resistance offered by flat surfaces to the air. It was in 1867
that the two brothers began really practical work, experimenting with
wings which, from their design, indicate some knowledge of Besnier
and the history of his gliding experiments; these wings the brothers
fastened to their backs, moving them with their legs after the fashion
of one attempting to swim. Before they had achieved any real success in
gliding the Franco-German war came as an interruption; both brothers
served in this campaign, resuming their experiments in 1871 at the
conclusion of hostilities.
The experiments made by the brothers previous to the war had convinced
Otto that previous experimenters in gliding flight had failed
through reliance on empirical conclusions or else through incomplete
observation on their own part, mostly of bird flight. From 1871 onward
Otto Lilienthal (Gustav’s interest in the problem was not maintained as
was his brother’s) made what is probably the most detailed and accurate
series of observations that has ever been made with regard to the
properties of curved wing surfaces. So far as could be done, Lilienthal
tabulated the amount of air resistance offered to a bird’s wing,
ascertaining that the curve is necessary to flight, as offering far
more resistance than a flat surface. Cayley, and others, had already
stated this, but to Lilienthal belongs the honour of being first to
put the statement to effective proof--he made over 2,000 gliding
flights between 1891 and the regrettable end of his experiments; his
practical conclusions are still regarded as part of the accepted theory
of students of flight. In 1889 he published a work on the subject of
gliding flight which stands as data for investigators, and, on the
conclusions embodied in this work, he began to build his gliders and
practise what he had preached, turning from experiment with models to
wings that he could use.
It was in the summer of 1891 that he built his first glider of rods
of peeled willow, over which was stretched strong cotton fabric; with
this, which had a supporting surface of about 100 square feet, Otto
Lilienthal launched himself in the air from a spring board, making
glides which, at first of only a few feet, gradually lengthened. As
his experience of the supporting qualities of the air progressed he
gradually altered his designs until, when Pilcher visited him in the
spring of 1895, he experimented with a glider, roughly made of peeled
willow rods and cotton fabric, having an area of 150 square feet and
weighing half a hundredweight. By this time Lilienthal had moved from
his springboard to a conical artificial hill which he had had thrown up
on level ground at Grosse Lichterfelde, near Berlin. This hill was made
with earth taken from the excavations incurred in constructing a canal,
and had a cave inside in which Lilienthal stored his machines. Pilcher,
in his paper on ‘Gliding,’[1] gives an excellent short summary of
Lilienthal’s experiments, from which the following extracts are taken:--
‘At first Lilienthal used to experiment by jumping off a springboard
with a good run. Then he took to practising on some hills close to
Berlin. In the summer of 1892 he built a flat-roofed hut on the summit
of a hill, from the top of which he used to jump, trying, of course,
to soar as far as possible before landing.... One of the great dangers
with a soaring machine is losing forward speed, inclining the machine
too much down in front, and coming down head first. Lilienthal was the
first to introduce the system of handling a machine in the air merely
by moving his weight about in the machine; he always rested only on his
elbows or on his elbows and shoulders....
‘In 1892 a canal was being cut, close to where Lilienthal lived, in the
suburbs of Berlin, and with the surplus earth Lilienthal had a special
hill thrown up to fly from. The country round is as flat as the sea,
and there is not a house or tree near it to make the wind unsteady, so
this was an ideal practising ground; for practising on natural hills is
generally rendered very difficult by shifty and gusty winds.... This
hill is 50 feet high, and conical. Inside the hill there is a cave for
the machines to be kept in.... When Lilienthal made a good flight he
used to land 300 feet from the centre of the hill, having come down at
an angle of 1 in 6; but his best flights have been at an angle of about
1 in 10.
‘If it is calm, one must run a few steps down the hill, holding the
machine as far back on oneself as possible, when the air will gradually
support one, and one slides off the hill into the air. If there is any
wind, one should face it at starting; to try to start with a side wind
is most unpleasant. It is possible after a great deal of practice to
turn in the air, and fairly quickly. This is accomplished by throwing
one’s weight to one side, and thus lowering the machine on that side
towards which one wants to turn. Birds do the same thing--crows and
gulls show it very clearly. Last year Lilienthal chiefly experimented
with double-surfaced machines. These were very much like the old
machines with awnings spread above them.
‘The object of making these double-surfaced machines was to get more
surface without increasing the length and width of the machine. This,
of course, it does, but I personally object to any machine in which
the wing surface is high above the weight. I consider that it makes
the machine very difficult to handle in bad weather, as a puff of wind
striking the surface, high above one, has a great tendency to heel the
machine over.
‘Herr Lilienthal kindly allowed me to sail down his hill in one of
these double-surfaced machines last June. With the great facility
afforded by his conical hill the machine was handy enough; but I am
afraid I should not be able to manage one at all in the squally
districts I have had to practise in over here.
‘Herr Lilienthal came to grief through deserting his old method of
balancing. In order to control his tipping movements more rapidly he
attached a line from his horizontal rudder to his head, so that when he
moved his head forward it would lift the rudder and tip the machine up
in front, and vice versa. He was practising this on some natural hills
outside Berlin, and he apparently got muddled with the two motions,
and, in trying to regain speed after he had, through a lull in the
wind, come to rest in the air, let the machine get too far down in
front, came down head first and was killed.’
Then in another passage Pilcher enunciates what is the true value of
such experiments as Lilienthal--and, subsequently, he himself--made:
‘The object of experimenting with soaring machines,’ he says, ‘is to
enable one to have practice in starting and alighting and controlling
a machine in the air. They cannot possibly float horizontally in the
air for any length of time, but to keep going must necessarily lose in
elevation. They are excellent schooling machines, and that is all they
are meant to be, until power, in the shape of an engine working a screw
propeller, or an engine working wings to drive the machine forward, is
added; then a person who is used to soaring down a hill with a simple
soaring machine will be able to fly with comparative safety. One can
best compare them to bicycles having no cranks, but on which one could
learn to balance by coming down an incline.’
It was in 1895 that Lilienthal passed from experiment with the
monoplane type of glider to the construction of a biplane glider
which, according to his own account, gave better results than his
previous machines. ‘Six or seven metres velocity of wind,’ he says,
‘sufficed to enable the sailing surface of 18 square metres to carry me
almost horizontally against the wind from the top of my hill without
any starting jump. If the wind is stronger I allow myself to be simply
lifted from the point of the hill and to sail slowly towards the wind.
The direction of the flight has, with strong wind, a strong upwards
tendency. I often reach positions in the air which are much higher than
my starting point. At the climax of such a line of flight I sometimes
come to a standstill for some time, so that I am enabled while floating
to speak with the gentlemen who wish to photograph me, regarding the
best position for the photographing.’
Lilienthal’s work did not end with simple gliding, though he did not
live to achieve machine-driven flight. Having, as he considered, gained
sufficient experience with gliders, he constructed a power-driven
machine which weighed altogether about 90 lbs., and this was thoroughly
tested. The extremities of its wings were made to flap, and the driving
power was obtained from a cylinder of compressed carbonic acid gas,
released through a hand-operated valve which, Lilienthal anticipated,
would keep the machine in the air for four minutes. There were certain
minor accidents to the mechanism, which delayed the trial flights,
and on the day that Lilienthal had determined to make his trial he
made a long gliding flight with a view to testing a new form of rudder
that--as Pilcher relates--was worked by movements of his head. His
death came about through the causes that Pilcher states; he fell from
a height of 50 feet, breaking his spine, and the next day he died.
It may be said that Lilienthal accomplished as much as any one of the
great pioneers of flying. As brilliant in his conceptions as da Vinci
had been in his, and as conscientious a worker as Borelli, he laid the
foundations on which Pilcher, Chanute, and Professor Montgomery were
able to build to such good purpose. His book on bird flight, published
in 1889, with the authorship credited both to Otto and his brother
Gustav, is regarded as epoch-making; his gliding experiments are no
less entitled to this description.
In England Lilienthal’s work was carried on by Percy Sinclair Pilcher,
who, born in 1866, completed six years’ service in the British Navy
by the time that he was nineteen, and then went through a course of
engineering, subsequently joining Maxim in his experimental work. It
was not until 1895 that he began to build the first of the series of
gliders with which he earned his plane among the pioneers of flight.
Probably the best account of Pilcher’s work is that given in the
_Aeronautical Classics_ issued by the Royal Aeronautical Society, from
which the following account of Pilcher’s work is mainly abstracted.[2]
The ‘Bat,’ as Pilcher named his first glider, was a monoplane which he
completed before he paid his visit to Lilienthal in 1895. Concerning
this Pilcher stated that he purposely finished his own machine before
going to see Lilienthal, so as to get the greatest advantage from any
original ideas he might have; he was not able to make any trials with
this machine, however, until after witnessing Lilienthal’s experiments
and making several glides in the biplane glider which Lilienthal
constructed.
The wings of the ‘Bat’ formed a pronounced dihedral angle; the tips
being raised 4 feet above the body. The spars forming the entering
edges of the wings crossed each other in the centre and were lashed to
opposite sides of the triangle that served as a mast for the stay-wires
that guyed the wings. The four ribs of each wing, enclosed in pockets
in the fabric, radiated fanwise from the centre, and were each stayed
by three steel piano-wires to the top of the triangular mast, and
similarly to its base. These ribs were bolted down to the triangle at
their roots, and could be easily folded back on to the body when the
glider was not in use. A small fixed vertical surface was carried in
the rear. The framework and ribs were made entirely of Riga pine; the
surface fabric was nainsook. The area of the machine was 150 square
feet; its weight 45 lbs.; so that in flight, with Pilcher’s weight of
145 lbs. added, it carried one and a half pounds to the square foot.
[Illustration: Rear view of Pilcher’s ‘Beetle.’]
[Illustration: The ‘Beetle.’ side view.]
[Illustration: Pilcher starting on glide with the ‘Bat.’]
Pilcher’s first glides, which he carried out on a grass hill on
the banks of the Clyde near Cardross, gave little result, owing to
the exaggerated dihedral angle of the wings, and the absence of a
horizontal tail. The ‘Bat’ was consequently reconstructed with a
horizontal tail-plane added to the vertical one, and with the wings
lowered so that the tips were only six inches above the level of the
body. The machine now gave far better results; on the first glide into
a head wind Pilcher rose to a height of twelve feet and remained in
the air for a third of a minute; in the second attempt a rope was used
to tow the glider, which rose to twenty feet and did not come to earth
again until nearly a minute had passed. With experience Pilcher was
able to lengthen his glide and improve his balance, but the dropped
wing tips made landing difficult, and there were many breakages.
In consequence of this Pilcher built a second glider which he named
the ‘Beetle,’ because, as he said, it looked like one. In this the
square-cut wings formed almost a continuous plane, rigidly fixed to
the central body, which consisted of a shaped girder. These wings were
built up of five transverse bamboo spars, with two shaped ribs running
from fore to aft of each wing, and were stayed overhead to a couple
of masts. The tail, consisting of two discs placed crosswise (the
horizontal one alone being movable), was carried high up in the rear.
With the exception of the wing-spars, the whole framework was built of
white pine. The wings in this machine were actually on a higher level
than the operator’s head; the centre of gravity was, consequently, very
low, a fact which, according to Pilcher’s own account, made the glider
very difficult to handle. Moreover, the weight of the ‘Beetle,’ 80
lbs., was considerable; the body had been very solidly built to enable
it to carry the engine which Pilcher was then contemplating; so that
the glider carried some 225 lbs. with its area of 170 square feet-too
great a mass for a single man to handle with comfort.
It was in the spring of 1896 that Pilcher built his third glider,
the ‘Gull,’ with 300 square feet of area and a weight of 55 lbs. The
size of this machine rendered it unsuitable for experiment in any but
very calm weather, and it incurred such damage when experiments were
made in a breeze that Pilcher found it necessary to build a fourth,
which he named the ‘Hawk.’ This machine was very soundly built, being
constructed of bamboo, with the exception of the two main transverse
beams. The wings were attached to two vertical masts, 7 feet high, and
8 feet apart, joined at their summits and their centres by two wooden
beams. Each wing had nine bamboo ribs, radiating from its mast, which
was situated at a distance of 2 feet 6 inches from the forward edge
of the wing. Each rib was rigidly stayed at the top of the mast by
three tie-wires, and by a similar number to the bottom of the mast, by
which means the curve of each wing was maintained uniformly. The tail
was formed of a triangular horizontal surface to which was affixed a
triangular vertical surface, and was carried from the body on a high
bamboo mast, which was also stayed from the masts by means of steel
wires, but only on its upper surface, and it was the snapping of one
of these guy wires which caused the collapse of the tail support and
brought about the fatal end of Pilcher s experiments. In flight,
Pilcher’s head, shoulders, and the greater part of his chest projected
above the wings. He took up his position by passing his head and
shoulders through the top aperture formed between the two wings, and
resting his forearms on the longitudinal body members. A very simple
form of undercarriage, which took the weight off the glider on the
ground, was fitted, consisting of two bamboo rods with wheels suspended
on steel springs.
Balance and steering were effected, apart from the high degree of
inherent stability afforded by the tail, as in the case of Lilienthal’s
glider, by altering the position of the body. With this machine Pilcher
made some twelve glides at Eynsford in Kent in the summer of 1896,
and as he progressed he increased the length of his glides, and also
handled the machine more easily, both in the air and in landing. He was
occupied with plans for fitting an engine and propeller to the ‘Hawk,’
but, in these early days of the internal combustion engine, was unable
to get one light enough for his purpose. There were rumours of an
engine weighing 15 lbs. which gave 1 horse-power, and was reported to
be in existence in America, but it could not be traced.
In the spring of 1897 Pilcher took up his gliding experiments again,
obtaining what was probably the best of his glides on June 19th, when
he alighted after a perfectly balanced glide of over 250 yards in
length, having crossed a valley at a considerable height. From his
various experiments he concluded that once the machine was launched
in the air an engine of, at most, 3 horse-power would suffice for
the maintenance of horizontal flight, but he had to allow for the
additional weight of the engine and propeller, and taking into account
the comparative inefficiency of the propeller, he planned for an engine
of 4 horse-power. Engine and propeller together were estimated at under
44 lbs. weight, the engine was to be fitted in front of the operator,
and by means of an overhead shaft was to operate the propeller
situated in rear of the wings. 1898 went by while this engine was
under construction. Then in 1899 Pilcher became interested in Lawrence
Hargrave’s soaring kites, with which he carried out experiments during
the summer of 1899. It is believed that he intended to incorporate
a number of these kites in a new machine, a triplane, of which the
fragments remaining are hardly sufficient to reconstitute the complete
glider. This new machine was never given a trial, for on September
30th, 1899, at Stamford Hall, Market Harborough, Pilcher agreed to
give a demonstration of gliding flight, but owing to the unfavourable
weather he decided to postpone the trial of the new machine and to
experiment with the ‘Hawk,’ which was intended to rise from a level
field, towed by a line passing over a tackle drawn by two horses. At
the first trial the machine rose easily, but the tow-line snapped when
it was well clear of the ground, and the glider descended, weighed down
through being sodden with rain. Pilcher resolved on a second trial, in
which the glider again rose easily to about thirty feet, when one of
the guy wires of the tail broke, and the tail collapsed; the machine
fell to the ground, turning over, and Pilcher was unconscious when he
was freed from the wreckage.
Hopes were entertained of his recovery, but he died on Monday, October
2nd, 1899, aged only thirty-four. His work in the cause of flying
lasted only four years, but in that time his actual accomplishments
were sufficient to place his name beside that of Lilienthal, with whom
he ranks as one of the greatest exponents of gliding flight.
[Illustration: ‘The Hawk’--front view.]
[Illustration: ‘The Hawk’--rear view.]
[Illustration: ‘The Hawk’--in flight with Pilcher.]
VIII
AMERICAN GLIDING EXPERIMENTS
While Pilcher was carrying on Lilienthal’s work in England, the great
German had also a follower in America; one Octave Chanute, who, in one
of the statements which he has left on the subject of his experiments
acknowledges forty years’ interest in the problem of flight, did more
to develop the glider in America than--with the possible exception
of Montgomery--any other man. Chanute had all the practicality of an
American; he began his work, so far as actual gliding was concerned,
with a full-sized glider of the Lilienthal type, just before Lilienthal
was killed. In a rather rare monograph, entitled _Experiments in
Flying_, Chanute states that he found the Lilienthal glider hazardous
and decided to test the value of an idea of his own; in this he
followed the same general method, but reversed the principle upon
which Lilienthal had depended for maintaining his equilibrium in the
air. Lilienthal had shifted the weight of his body, under immovable
wings, as fast and as far as the sustaining pressure varied under his
surfaces; this shifting was mainly done by moving the feet, as the
actions required were small except when alighting. Chanute’s idea was
to have the operator remain seated in the machine in the air, and to
intervene only to steer or to alight; moving mechanism was provided
to adjust the wings automatically, in order to restore balance when
necessary.
Chanute realised that experiments with models were of little use; in
order to be fully instructive, these experiments should be made with a
full-sized machine which carried its operator, for models seldom fly
twice alike in the open air, and no relation can be gained from them
of the divergent air currents which they have experienced. Chanute’s
idea was that any flying machine which might be constructed must
be able to operate in a wind; hence the necessity for an operator
to report upon what occurred in flight, and to acquire practical
experience of the work of the human factor in imitation of bird
flight. From this point of view he conducted his own experiments;
it must be noted that he was over sixty years of age when he began,
and, being no longer sufficiently young and active to perform any but
short and insignificant glides, the courage of the man becomes all the
more noteworthy; he set to work to evolve the state required by the
problem of stability, and without any expectation of advancing to the
construction of a flying machine which might be of commercial value.
His main idea was the testing of devices to secure equilibrium; for
this purpose he employed assistants to carry out the practical work,
where he himself was unable to supply the necessary physical energy.
Together with his assistants he found a suitable place for experiments
among the sandhills on the shore of Lake Michigan, about thirty miles
eastward from Chicago. Here a hill about ninety-five feet high was
selected as a point from which Chanute’s gliders could set off; in
practice, it was found that the best observation was to be obtained
from short glides at low speed, and, consequently, a hill which was
only sixty-one feet above the shore of the lake was employed for the
experimental work done by the party.
In the years 1896 and 1897, with parties of from four to six persons,
five full-sized gliders were tried out, and from these two distinct
types were evolved: of these one was a machine consisting of five tiers
of wings and a steering tail, and the other was of the biplane type;
Chanute believed these to be safer than any other machine previously
evolved, solving, as he states in his monograph, the problem of
inherent equilibrium as fully as this could be done. Unfortunately,
very few photographs were taken of the work in the first year, but one
view of a multiple wing-glider survives, showing the machine in flight.
In 1897 a series of photographs was taken exhibiting the consecutive
phases of a single flight; this series of photographs represents the
experience gained in a total of about one thousand glides, but the
point of view was varied so as to exhibit the consecutive phases of one
single flight.
The experience gained is best told in Chanute’s own words. ‘The first
thing,’ he says, ‘which we discovered practically was that the wind
flowing up a hill-side is not a steadily-flowing current like that
of a river. It comes as a rolling mass, full of tumultuous whirls
and eddies, like those issuing from a chimney; and they strike the
apparatus with constantly varying force and direction, sometimes
withdrawing support when most needed. It has long been known, through
instrumental observations, that the wind is constantly changing in
force and direction; but it needed the experience of an operator afloat
on a gliding machine to realise that this all proceeded from cyclonic
action; so that more was learned in this respect in a week than had
previously been acquired by several years of experiments with models.
There was a pair of eagles, living in the top of a dead tree about two
miles from our tent, that came almost daily to show us how such wind
effects are overcome and utilised. The birds swept in circles overhead
on pulseless wings, and rose high up in the air. Occasionally there
was a side-rocking motion, as of a ship rolling at sea, and then the
birds rocked back to an even keel; but although we thought the action
was clearly automatic, and were willing to learn, our teachers were too
far off to show us just how it was done, and we had to experiment for
ourselves.’
Chanute provided his multiple glider with a seat, but, since each
glide only occupied between eight and twelve seconds, there was
little possibility of the operator seating himself. With the multiple
glider a pair of horizontal bars provided rest for the arms, and
beyond these was a pair of vertical bars which the operator grasped
with his hands; beyond this, the operator was in no way attached to
the machine. He took, at the most, four running steps into the wind,
which launched him in the air, and thereupon he sailed into the wind
on a generally descending course. In the matter of descent Chanute
observed the sparrow and decided to imitate it. ‘When the latter,’
he says, ‘approaches the street, he throws his body back, tilts his
outspread wings nearly square to the course, and on the cushion of air
thus encountered he stops his speed and drops lightly to the ground.
So do all birds. We tried it with misgivings, but found it perfectly
effective. The soft sand was a great advantage, and even when the
experts were racing there was not a single sprained ankle.’
With the multiple winged glider some two to three hundred glides were
made without any accident either to the man or to the machine, and the
action was found so effective, the principle so sound, that full plans
were published for the benefit of any experimenters who might wish to
improve on this apparatus. The American _Aeronautical Annual_ for 1897
contains these plans; Chanute confessed that some movement on the part
of the operator was still required to control the machine, but it was
only a seventh or a sixth part of the movement required for control of
the Lilienthal type.
Chanute waxed enthusiastic over the possibilities of gliding,
concerning which he remarks that ‘There is no more delightful sensation
than that of gliding through the air. All the faculties are on the
alert, and the motion is astonishingly smooth and elastic. The machine
responds instantly to the slightest movement of the operator; the air
rushes by one’s ears; the trees and bushes flit away underneath, and
the landing comes all too quickly. Skating, sliding, and bicycling
are not to be compared for a moment to aerial conveyance, in which,
perhaps, zest is added by the spice of danger. For it must be
distinctly understood that there is constant danger in such preliminary
experiments. When this hazard has been eliminated by further evolution,
gliding will become a most popular sport.’
Later experiments proved that the biplane type of glider gave better
results than the rather cumbrous model consisting of five tiers of
planes. Longer and more numerous glides, to the number of seven to
eight hundred, were obtained, the rate of descent being about one in
six. The longest distance traversed was about 120 yards, but Chanute
had dreams of starting from a hill about 200 feet high, which would
have given him gliding flights of 1,200 feet. He remarked that ‘In
consequence of the speed gained by running, the initial stage of the
flight is nearly horizontal, and it is thrilling to see the operator
pass from thirty to forty feet overhead, steering his machine,
undulating his course, and struggling with the wind-gusts which whistle
through the guy wires. The automatic mechanism restores the angle of
advance when compromised by variations of the breeze; but when these
come from one side and tilt the apparatus, the weight has to be shifted
to right the machine ... these gusts sometimes raise the machine from
ten to twenty feet vertically, and sometimes they strike the apparatus
from above, causing it to descend suddenly. When sailing near the
ground, these vicissitudes can be counteracted by movements of the
body from three to four inches; but this has to be done instantly,
for neither wings nor gravity will wait on meditation. At a height
of three hundred or four hundred feet the regulating mechanism would
probably take care of these wind-gusts, as it does, in fact, for their
minor variations. The speed of the machine is generally about seventeen
miles an hour over the ground, and from twenty-two to thirty miles an
hour relative to the air. Constant effort was directed to keep down
the velocity, which was at times fifty-two miles an hour. This is
the purpose of the starting and gliding against the wind, which thus
furnishes an initial velocity without there being undue speed at the
landing. The highest wind we dared to experiment in blew at thirty-one
miles an hour; when the wind was stronger, we waited and watched the
birds.’
Chanute details an amusing little incident which occurred in the course
of experiment with the biplane glider. He says that ‘We had taken one
of the machines to the top of the hill, and loaded its lower wings
with sand to hold it while we went to lunch. A gull came strolling
inland, and flapped full-winged to inspect. He swept several circles
above the machine, stretched his neck, gave a squawk and went off.
Presently he returned with eleven other gulls, and they seemed to hold
a conclave about one hundred feet above the big new white bird which
they had discovered on the sand. They circled round after round, and
once in a while there was a series of loud peeps, like those of a rusty
gate, as if in conference, with sudden flutterings, as if a terrifying
suggestion had been made. The bolder birds occasionally swooped
downwards to inspect the monster more closely; they twisted their heads
around to bring first one eye and then the other to bear, and then they
rose again. After some seven or eight minutes of this performance,
they evidently concluded either that the stranger was too formidable
to tackle, if alive, or that he was not good to eat, if dead, and they
flew off to resume fishing, for the weak point about a bird is his
stomach.’
The gliders were found so stable, more especially the biplane form,
that in the end Chanute permitted amateurs to make trials under
guidance, and throughout the whole series of experiments not a single
accident occurred. Chanute came to the conclusion that any young,
quick, and handy man could master a gliding machine almost as soon
as he could get the hang of a bicycle, although the penalty for any
mistake would be much more severe.
At the conclusion of his experiments he decided that neither the
multiple plane nor the biplane type of glider was sufficiently
perfected for the application of motive power. In spite of the amount
of automatic stability that he had obtained he considered that there
was yet more to be done, and he therefore advised that every possible
method of securing stability and safety should be tested, first with
models, and then with full-sized machines; designers, he said, should
make a point of practice in order to make sure of the action, to
proportion and adjust the parts of their machine, and to eliminate
hidden defects. Experimental flight, he suggested, should be tried
over water, in order to break any accidental fall; when a series of
experiments had proved the stability of a glider, it would then be time
to apply motive power. He admitted that such a process would be both
costly and slow, but, he said, that ‘it greatly diminished the chance
of those accidents which bring a whole line of investigation into
contempt.’ He saw the flying machine as what it has, in fact, been; a
child of evolution, carried on step by step by one investigator after
another, through the stages of doubt and perplexity which lie behind
the realm of possibility, beyond which is the present day stage of
actual performance and promise of ultimate success and triumph over the
earlier, more cumbrous, and slower forms of the transport that we know.
[Illustration: Chanute biplane glider.]
Chanute’s monograph, from which the foregoing notes have been
comprised, was written soon after the conclusion of his series of
experiments. He does not appear to have gone in for further practical
work, but to have studied the subject from a theoretical view-point
and with great attention to the work done by others. In a paper
contributed in 1900 to the American _Independent_, he remarks that
‘Flying machines promise better results as to speed, but yet will be of
limited commercial application. They may carry mails and reach other
inaccessible places, but they cannot compete with railroads as carriers
of passengers or freight. They will not fill the heavens with commerce,
abolish custom houses, or revolutionise the world, for they will be
expensive for the loads which they can carry, and subject to too many
weather contingencies. Success is, however, probable. Each experimenter
has added something to previous knowledge which his successors can
avail of. It now seems likely that two forms of flying machines, a
sporting type and an exploration type, will be gradually evolved within
one or two generations, but the evolution will be costly and slow, and
must be carried on by well-equipped and thoroughly informed scientific
men; for the casual inventor, who relies upon one or two happy
inspirations, will have no chance of success whatever.’
Follows Professor John J. Montgomery, who, in the true American spirit,
describes his own experiments so well that nobody can possibly do it
better. His account of his work was given first of all in the American
Journal, _Aeronautics_, in January, 1909, and thence transcribed in
the English paper of the same name in May, 1910, and that account is
here copied word for word. It may, however, be noted first that as
far back as 1860, when Montgomery was only a boy, he was attracted to
the study of aeronautical problems, and in 1883 he built his first
machine, which was of the flapping-wing ornithopter type, and which
showed its designer, with only one experiment, that he must design some
other form of machine if he wished to attain to a successful flight.
Chanute details how, in 1884 and 1885, Montgomery built three gliders,
demonstrating the value of curved surfaces. With the first of these
gliders Montgomery copied the wing of a seagull; with the second he
proved that a flat surface was virtually useless, and with the third
he pivoted his wings as in the Antoinette type of power-propelled
aeroplane, proving to his own satisfaction that success lay in this
direction. His own account of the gliding flights carried out under his
direction is here set forth, being the best description of his work
that can be obtained:--
‘When I commenced practical demonstration in my work with aeroplanes
I had before me three points; first, equilibrium; second, complete
control; and third, long continued or soaring flight. In starting I
constructed and tested three sets of models, each in advance of the
other in regard to the continuance of their soaring powers, but all
equally perfect as to equilibrium and control. These models were tested
by dropping them from a cable stretched between two mountain tops, with
various loads, adjustments and positions. And it made no difference
whether the models were dropped upside down or any other conceivable
position, they always found their equilibrium immediately and glided
safely to earth.
‘Then I constructed a large machine patterned after the first model,
and with the assistance of three cowboy friends personally made a
number of flights in the steep mountains near San Juan (a hundred
miles distant). In making these flights I simply took the aeroplane
and made a running jump. These tests were discontinued after I put my
foot into a squirrel hole in landing and hurt my leg.
The following year I commenced the work on a larger scale, by engaging
aeronauts to ride my aeroplane dropped from balloons. During this
work I used five hot-air balloons and one gas balloon, five or six
aeroplanes, three riders--Maloney, Wilkie, and Defolco--and had sixteen
applicants on my list, and had a training station to prepare any when I
needed them.
‘Exhibitions were given in Santa Cruz, San Jose, Santa Clara, Oakland,
and Sacramento. The flights that were made, instead of being haphazard
affairs, were in the order of safety and development. In the first
flight of an aeronaut the aeroplane was so arranged that the rider had
little liberty of action, consequently he could make only a limited
flight. In some of the first flights, the aeroplane did little more
than settle in the air. But as the rider gained experience in each
successive flight I changed the adjustments, giving him more liberty of
action, so he could obtain longer flights and more varied movements in
the flights. But in none of the flights did I have the adjustments so
that the riders had full liberty, as I did not consider that they had
the requisite knowledge and experience necessary for their safety; and
hence, none of my aeroplanes were launched so arranged that the rider
could make adjustments necessary for a full flight.
‘This line of action caused a good deal of trouble with aeronauts or
riders, who had unbounded confidence and wanted to make long flights
after the first few trials; but I found it necessary, as they seemed
slow in comprehending the important elements and were willing to
take risks. To give them the full knowledge in these matters I was
formulating plans for a large starting station on the Mount Hamilton
Range from which I could launch an aeroplane capable of carrying two,
one of my aeronauts and myself, so I could teach him by demonstration.
But the disasters consequent on the great earthquake completely stopped
all my work on these lines. The flights that were given were only the
first of the series with aeroplanes patterned after the first model.
There were no aeroplanes constructed according to the two other models,
as I had not given the full demonstration of the workings of the first,
though some remarkable and startling work was done. On one occasion
Maloney, in trying to make a very short turn in rapid flight, pressed
very hard on the stirrup which gives a screw-shape to the wings, and
made a side somersault. The course of the machine was very much like
one turn of a corkscrew. After this movement the machine continued
on its regular course. And afterwards Wilkie, not to be outdone by
Maloney, told his friends he would do the same, and in a subsequent
flight made two side somersaults, one in one direction and the other in
an opposite, then made a deep dive and a long glide, and, when about
three hundred feet in the air, brought the aeroplane to a sudden stop
and settled to the earth. After these antics, I decreased the extent of
the possible change in the form of wing-surface, so as to allow only
straight sailing or only long curves in turning.
‘During my work I had a few carping critics that I silenced by this
standing offer: If they would deposit a thousand dollars I would cover
it on this proposition. I would fasten a 150 pound sack of sand in the
rider’s seat, make the necessary adjustments, and send up an aeroplane
upside down with a balloon, the aeroplane to be liberated by a time
fuse. If the aeroplane did not immediately right itself, make a flight,
and come safely to the ground, the money was theirs.
‘Now a word in regard to the fatal accident. The circumstances are
these: The ascension was given to entertain a military company in which
were many of Maloney’s friends, and he had told them he would give the
most sensational flight they ever heard of. As the balloon was rising
with the aeroplane, a guy rope dropping switched around the right wing
and broke the tower that braced the two rear wings and which also gave
control over the tail. We shouted Maloney that the machine was broken,
but he probably did not hear us, as he was at the same time saying,
“Hurrah for Montgomery’s airship,” and as the break was behind him,
he may not have detected it. Now did he know of the breakage or not,
and if he knew of it did he take a risk so as not to disappoint his
friends? At all events, when the machine started on its flight the rear
wings commenced to flap (thus indicating they were loose), the machine
turned on its back, and settled a little faster than a parachute. When
we reached Maloney he was unconscious and lived only thirty minutes.
The only mark of any kind on him was a scratch from a wire on the side
of his neck. The six attending physicians were puzzled at the cause
of his death. This is remarkable for a vertical descent of over 2,000
feet.’
The flights were brought to an end by the San Francisco earthquake in
April, 1906, which, Montgomery states, ‘Wrought such a disaster that
I had to turn my attention to other subjects and let the aeroplane
rest for a time.’ Montgomery resumed experiments in 1911 in California,
and in October of that year an accident brought his work to an end.
The report in the American _Aeronautics_ says that ‘a little whirlwind
caught the machine and dashed it head on to the ground; Professor
Montgomery landed on his head and right hip. He did not believe himself
seriously hurt, and talked with his year-old bride in the tent. He
complained of pains in his back, and continued to grow worse until he
died.’
IX
NOT PROVEN
The early history of flying, like that of most sciences, is replete
with tragedies; in addition to these it contains one mystery concerning
Clement Ader, who was well known among European pioneers in the
development of the telephone, and first turned his attention to the
problems of mechanical flight in 1872. At the outset he favoured the
ornithopter principle, constructing a machine in the form of a bird
with a wing-spread of twenty-six feet; this, according to Ader’s
conception, was to fly through the efforts of the operator. The result
of such an attempt was past question and naturally the machine never
left the ground.
A pause of nineteen years ensued, and then in 1886 Ader turned his
mind to the development of the aeroplane, constructing a machine of
bat-like form with a wing-spread of about forty-six feet, a weight of
eleven hundred pounds, and a steam-power plant of between twenty and
thirty horse-power driving a four-bladed tractor screw. On October 9th,
1890, the first trials of this machine were made, and it was alleged
to have flown a distance of one hundred and sixty-four feet. Whatever
truth there may be in the allegation, the machine was wrecked through
deficient equilibrium at the end of the trial. Ader repeated the
construction, and on October 14th, 1897, tried out his third machine
at the military establishment at Satory in the presence of the French
military authorities, on a circular track specially prepared for the
experiment. Ader and his friends alleged that a flight of nearly a
thousand feet was made; again the machine was wrecked at the end of the
trial, and there Ader’s practical work may be said to have ended, since
no more funds were forthcoming for the subsidy of experiments.
There is the bald narrative, but it is worthy of some amplification. If
Ader actually did what he claimed, then the position which the Wright
Brothers hold as first to navigate the air in a power-driven plane is
nullified. Although at this time of writing it is not a quarter of a
century since Ader’s experiment in the presence of witnesses competent
to judge on his accomplishment, there is no proof either way, and
whether he was or was not the first man to fly remains a mystery in the
story of the conquest of the air.
The full story of Ader’s work reveals a persistence and determination
to solve the problem that faced him which was equal to that of
Lilienthal. He began by penetrating into the interior of Algeria after
having disguised himself as an Arab, and there he spent some months in
studying flight as practised by the vultures of the district. Returning
to France in 1886 he began to construct the ‘Eole,’ modelling it, not
on the vulture, but in the shape of a bat. Like the Lilienthal and
Pilcher gliders this machine was fitted with wings which could be
folded; the first flight made, as already noted, on October 9th, 1890,
took place in the grounds of the chateau d’Amainvilliers, near Bretz;
two fellow-enthusiasts named Espinosa and Vallier stated that a flight
was actually made; no statement in the history of aeronautics has been
subject of so much question, and the claim remains unproved.
It was in September of 1891 that Ader, by permission of the Minister of
War, moved the ‘Eole’ to the military establishment at Satory for the
purpose of further trial. By this time, whether he had flown or not,
his nineteen years of work in connection with the problems attendant
on mechanical flight had attracted so much attention that henceforth
his work was subject to the approval of the military authorities, for
already it was recognised that an efficient flying machine would confer
an inestimable advantage on the power that possessed it in the event
of war. At Satory the ‘Eole’ was alleged to have made a flight of 109
yards, or, according to another account, 164 feet, as stated above, in
the trial in which the machine wrecked itself through colliding with
some carts which had been placed near the track--the root cause of this
accident, however, was given as deficient equilibrium.
Whatever the sceptics may say, there is reason for belief in the
accomplishment of actual flight by Ader with his first machine in the
fact that, after the inevitable official delay of some months, the
French War Ministry granted funds for further experiment. Ader named
his second machine, which he began to build in May, 1892, the ‘Avion,’
and--an honour which he well deserves--that name remains in French
aeronautics as descriptive of the power-driven aeroplane up to this day.
This second machine, however, was not a success, and it was not
until 1897 that the second ‘Avion,’ which was the third power-driven
aeroplane of Ader’s construction, was ready for trial. This was
fitted with two steam motors of twenty horse-power each, driving two
four-bladed propellers; the wings warped automatically: that is to say,
if it were necessary to raise the trailing edge of one wing on the
turn, the trailing edge of the opposite wing was also lowered by the
same movement; an undercarriage was also fitted, the machine running on
three small wheels, and levers controlled by the feet of the aviator
actuated the movement of the tail planes.
On October the 12th, 1897, the first trials of this ‘Avion’ were made
in the presence of General Mensier, who admitted that the machine made
several hops above the ground, but did not consider the performance as
one of actual flight. The result was so encouraging, in spite of the
partial failure, that, two days later, General Mensier, accompanied by
General Grillon, a certain Lieutenant Binet, and two civilians named
respectively Sarrau and Leaute, attended for the purpose of giving the
machine an official trial, over which the great controversy regarding
Ader’s success or otherwise may be said to have arisen.
[Illustration: Course of the Avion’s Flight, October 14, 1897.]
We will take first Ader’s own statement as set out in a very competent
account of his work published in Paris in 1910. Here are Ader’s own
words: ‘After some turns of the propellers, and after travelling a few
metres, we started off at a lively pace; the pressure-gauge registered
about seven atmospheres; almost immediately the vibrations of the rear
wheel ceased; a little later we only experienced those of the front
wheels at intervals. Unhappily, the wind became suddenly strong, and
we had some difficulty in keeping the “Avion” on the white line. We
increased the pressure to between eight and nine atmospheres, and
immediately the speed increased considerably, and the vibrations of the
wheels were no longer sensible; we were at that moment at the point
marked G in the sketch; the “Avion” then found itself freely supported
by its wings; under the impulse of the wind it continually tended to
go outside the (prepared) area to the right, in spite of the action of
the rudder. On reaching the point V it found itself in a very critical
position; the wind blew strongly and across the direction of the white
line which it ought to follow; the machine then, although still going
forward, drifted quickly out of the area; we immediately put over the
rudder to the left as far as it would go; at the same time increasing
the pressure still more, in order to try to regain the course. The
“Avion” obeyed, recovered a little, and remained for some seconds
headed towards its intended course, but it could not struggle against
the wind; instead of going back, on the contrary it drifted farther and
farther away. And ill-luck had it that the drift took the direction
towards part of the School of Musketry, which was guarded by posts and
barriers. Frightened at the prospect of breaking ourselves against
these obstacles, surprised at seeing the earth getting farther away
from under the “Avion,” and very much impressed by seeing it rushing
sideways at a sickening speed, instinctively we stopped everything.
What passed through our thoughts at this moment which threatened a
tragic turn would be difficult to set down. All at once came a great
shock, splintering, a heavy concussion: we had landed.’
Thus speaks the inventor; the cold official mind gives out a different
account, crediting the ‘Avion’ with merely a few hops, and to-day,
among those who consider the problem at all, there is a little group
which persists in asserting that to Ader belongs the credit of the
first power-driven flight, while a larger group is equally persistent
in stating that, save for a few ineffectual hops, all three wheels of
the machine never left the ground. It is past question that the ‘Avion’
was capable of power-driven flight; whether it achieved it or no
remains an unsettled problem.
[Illustration: Clement Ader’s ‘Avion,’ with wings partly folded.]
Ader’s work is negative proof of the value of such experiments as
Lilienthal, Pilcher, Chanute, and Montgomery conducted; these four set
to work to master the eccentricities of the air before attempting to
use it as a supporting medium for continuous flight under power; Ader
attacked the problem from the other end; like many other experimenters
he regarded the air as a stable fluid capable of giving such support to
his machine as still water might give to a fish, and he reckoned that
he had only to produce the machine in order to achieve flight. The
wrecked ‘Avion’ and the refusal of the French War Ministry to grant any
more funds for further experiment are sufficient evidence of the need
for working along the lines taken by the pioneers of gliding rather
than on those which Ader himself adopted.
Let it not be thought that in this comment there is any desire to
derogate from the position which Ader should occupy in any study of
the pioneers of aeronautical enterprise. If he failed, he failed
magnificently, and if he succeeded, then the student of aeronautics
does him an injustice and confers on the Brothers Wright an honour
which, in spite of the value of their work, they do not deserve. There
was one earlier than Ader, Alphonse Penaud, who, in the face of a
lesser disappointment than that which Ader must have felt in gazing on
the wreckage of his machine, committed suicide; Ader himself, rendered
unable to do more, remained content with his achievement, and with the
knowledge that he had played a good part in the long search which must
eventually end in triumph. Whatever the world might say, he himself was
certain that he had achieved flight. This, for him, was perforce enough.
Before turning to consideration of the work accomplished by the
Brothers Wright, and their proved conquest of the air, it is necessary
first to sketch as briefly as may be the experimental work of Sir (then
Mr) Hiram Maxim, who, in his book, _Artificial and Natural Flight_, has
given a fairly complete account of his various experiments. He began by
experimenting with models, with screw-propelled planes so attached to a
horizontal movable arm that when the screw was set in motion the plane
described a circle round a central point, and, eventually, he built a
giant aeroplane having a total supporting area of 1,500 square feet,
and a wing-span of fifty feet. It has been thought advisable to give
a fairly full description of the power plant used to the propulsion
of this machine in the section devoted to engine development. The
aeroplane, as Maxim describes it, had five long and narrow planes
projecting from each side, and a main or central plane of pterygoid
aspect. A fore and aft rudder was provided, and had all the auxiliary
planes been put in position for experimental work a total lifting
surface of 6,000 square feet could have been obtained. Maxim, however,
did not use more than 4,000 square feet of lifting surface even in his
later experiments; with this he judged the machine capable of lifting
slightly under 8,000 lbs. weight, made up of 600 lbs. water in the
boiler and tank, a crew of three men, a supply of naphtha fuel, and the
weight of the machine itself.
Maxim’s intention was, before attempting free flight, to get as much
data as possible regarding the conditions under which flight must
be obtained, by what is known in these days as ‘taxi-ing’--that is,
running the propellers at sufficient speed to drive the machine along
the ground without actually mounting into the air. He knew that he had
an immense lifting surface and a tremendous amount of power in his
engine even when the total weight of the experimental plant was taken
into consideration, and thus he set about to devise some means of
keeping the machine on the nine foot gauge rail track which had been
constructed for the trials. At the outset he had a set of very heavy
cast-iron wheels made on which to mount the machine, the total weight
of wheels, axles, and connections being about one and a half tons.
These were so constructed that the light flanged wheels which supported
the machine on the steel rails could be lifted six inches above the
track, still leaving the heavy wheels on the rails for guidance of
the machine. ‘This arrangement,’ Maxim states, ‘was tried on several
occasions, the machine being run fast enough to lift the forward end
off the track. However, I found considerable difficulty in starting
and stopping quickly on account of the great weight, and the amount of
energy necessary to set such heavy wheels spinning at a high velocity.
The last experiment with these wheels was made when a head wind was
blowing at the rate of about ten miles an hour. It was rather unsteady,
and when the machine was running at its greatest velocity, a sudden
gust lifted not only the front end, but also the heavy front wheels
completely off the track, and the machine falling on soft ground was
soon blown over by the wind.’
Consequently, a safety track was provided, consisting of squared pine
logs, three inches by nine inches, placed about two feet above the
steel way and having a thirty-foot gauge. Four extra wheels were fitted
to the machine on outriggers and so adjusted that, if the machine
should lift one inch clear of the steel rails, the wheels at the ends
of the outriggers would engage the under side of the pine trackway.
The first fully loaded run was made in a dead calm with 150 lbs. steam
pressure to the square inch, and there was no sign of the wheels
leaving the steel track. On a second run, with 230 lbs. steam pressure
the machine seemed to alternate between adherence to the lower and
upper tracks, as many as three of the outrigger wheels engaging at the
same time, and the weight on the steel rails being reduced practically
to nothing. In preparation for a third run, in which it was intended
to use full power, a dynamometer was attached to the machine and
the engines were started at 200 lbs. pressure, which was gradually
increased to 310 lbs per square inch. The incline of the track, added
to the reading of the dynamometer, showed a total screw thrust of 2,164
lbs. After the dynamometer test had been completed, and everything had
been made ready for trial in motion, careful observers were stationed
on each side of the track, and the order was given to release the
machine. What follows is best told in Maxim’s own words:--
‘The enormous screw-thrust started the engine so quickly that it nearly
threw the engineers off their feet, and the machine bounded over
the track at a great rate. Upon noticing a slight diminution in the
steam pressure, I turned on more gas, when almost instantly the steam
commenced to blow a steady blast from the small safety valve, showing
that the pressure was at least 320 lbs. in the pipes supplying the
engines with steam. Before starting on this run, the wheels that were
to engage the upper track were painted, and it was the duty of one of
my assistants to observe these wheels during the run, while another
assistant watched the pressure gauges and dynagraphs. The first part
of the track was up a slight incline, but the machine was lifted clear
of the lower rails and all of the top wheels were fully engaged on the
upper track when about 600 feet had been covered. The speed rapidly
increased, and when 900 feet had been covered, one of the rear axle
trees, which were of two-inch steel tubing, doubled up and set the
rear end of the machine completely free. The pencils ran completely
across the cylinders of the dynagraphs and caught on the underneath
end. The rear end of the machine being set free, raised considerably
above the track and swayed. At about 1,000 feet, the left forward wheel
also got clear of the upper track, and shortly afterwards the right
forward wheel tore up about 100 feet of the upper track. Steam was at
once shut off and the machine sank directly to the earth, embedding
the wheels in the soft turf without leaving any other marks, showing
most conclusively that the machine was completely suspended in the
air before it settled to the earth. In this accident, one of the pine
timbers forming the upper track went completely through the lower
framework of the machine and broke a number of the tubes, but no damage
was done to the machinery except a slight injury to one of the screws.’
It is a pity that the multifarious directions in which Maxim turned
his energies did not include further development of the aeroplane, for
it seems fairly certain that he was as near solution of the problem
as Ader himself, and, but for the holding-down outer track, which was
really the cause of his accident, his machine would certainly have
achieved free flight, though whether it would have risen, flown and
alighted, without accident, is matter for conjecture.
The difference between experiments with models and with full-sized
machines is emphasised by Maxim’s statement to the effect that with
a small apparatus for ascertaining the power required for artificial
flight, an angle of incidence of one in fourteen was most advantageous,
while with a large machine he found it best to increase his angle to
one in eight in order to get the maximum lifting effect on a short
run at a moderate speed. He computed the total lifting effect in the
experiments which led to the accident as not less than 10,000 lbs., in
which is proof that only his rail system prevented free flight.
X
SAMUEL PIERPOINT LANGLEY
Langley was an old man when he began the study of aeronautics, or, as
he himself might have expressed it, the study of aerodromics, since he
persisted in calling the series of machines he built ‘Aerodromes,’ a
word now used only to denote areas devoted to use as landing spaces for
flying machines; the Wright Brothers, on the other hand, had the great
gift of youth to aid them in their work. Even so it was a great race
between Langley, aided by Charles Manly, and Wilbur and Orville Wright,
and only the persistent ill-luck which dogged Langley from the start
to the finish of his experiments gave victory to his rivals. It has
been proved conclusively in these later years of accomplished flight
that the machine which Langley launched on the Potomac River in October
of 1903 was fully capable of sustained flight, and only the accidents
incurred in launching prevented its pilot from being the first man to
navigate the air successfully in a power-driven machine.
The best account of Langley’s work is that diffused throughout a
weighty tome issued by the Smithsonian Institution, entitled the
_Langley Memoir on Mechanical Flight_, of which about one-third was
written by Langley himself, the remainder being compiled by Charles
M. Manly, the engineer responsible for the construction of the first
radial aero engine, and chief assistant to Langley in his experiments.
To give a twentieth of the contents of this volume in the present
short account of the development of mechanical flight would far exceed
the amount of space that can be devoted even to so eminent a man in
aeronautics as S. P. Langley, who, apart from his achievement in the
construction of a power-driven aeroplane really capable of flight,
was a scientist of no mean order, and who brought to the study of
aeronautics the skill of the trained investigator allied to the
inventive resource of the genius.
That genius exemplified the antique saw regarding the infinite capacity
for taking pains, for the Langley Memoir shows that as early as 1891
Langley had completed a set of experiments, lasting through years,
which proved it possible to construct machines giving such a velocity
to inclined surfaces that bodies indefinitely heavier than air could
be sustained upon it and propelled through it at high speed. For full
account (very full) of these experiments, and of a later series leading
up to the construction of a series of ‘model aerodromes’ capable of
flight under power, it is necessary to turn to the bulky memoir of
Smithsonian origin.
[Illustration: Quarter-size model, Langley Aerodrome, in flight, 8th
August, 1903.
Langley Memoir on Mechanical Flight, Smithsonian Institution,
Washington.]
The account of these experiments as given by Langley himself reveals
the humility of the true investigator. Concerning them, Langley remarks
that, ‘Everything here has been done with a view to putting a trial
aerodrome successfully in flight within a few years, and thus giving an
early demonstration of the only kind which is conclusive in the eyes of
the scientific man, as well as of the general public--a demonstration
that mechanical flight is possible--by actually flying. All that has
been done has been with an eye principally to this immediate result,
and all the experiments given in this book are to be considered only
as approximations to exact truth. All were made with a view, not to
some remote future, but to an arrival within the compass of a few years
at some result in actual flight that could not be gainsaid or mistaken.’
With a series of over thirty rubber-driven models Langley demonstrated
the practicability of opposing curved surfaces to the resistance of the
air in such a way as to achieve flight, in the early nineties of last
century; he then set about finding the motive power which should permit
of the construction of larger machines, up to man-carrying size. The
internal combustion engine was then an unknown quantity, and he had to
turn to steam, finally, as the propulsive energy for his power plant.
The chief problem which faced him was that of the relative weight and
power of his engine; he harked back to the Stringfellow engine of 1868,
which in 1889 came into the possession of the Smithsonian Institution
as a historical curiosity. Rightly or wrongly Langley concluded on
examination that this engine never had developed and never could
develop more than a tenth of the power attributed to it; consequently
he abandoned the idea of copying the Stringfellow design and set about
making his own engine.
How he overcame the various difficulties that faced him and constructed
a steam-engine capable of the task allotted to it forms a story in
itself, too long for recital here. His first power-driven aerodrome of
model size was begun in November of 1891, the scale of construction
being decided with the idea that it should be large enough to carry an
automatic steering apparatus which would render the machine capable of
maintaining a long and steady flight. The actual weight of the first
model far exceeded the theoretical estimate, and Langley found that a
constant increase of weight under the exigencies of construction was
a feature which could never be altogether eliminated. The machine was
made principally of steel, the sustaining surfaces being composed of
silk stretched from a steel tube with wooden attachments. The first
engines were the oscillating type, but were found deficient in power.
This led to the construction of single-acting inverted oscillating
engines with high and low pressure cylinders, and with admission and
exhaust ports to avoid the complication and weight of eccentric and
valves. Boiler and furnace had to be specially designed; an analysis
of sustaining surfaces and the settlement of equilibrium while in
flight had to be overcome, and then it was possible to set about the
construction of the series of model aerodromes and make test of their
‘lift.’
By the time Langley had advanced sufficiently far to consider it
possible to conduct experiments in the open air, even with these
models, he had got to his fifth aerodrome, and to the year 1894.
Certain tests resulted in failure, which in turn resulted in further
modifications of design, mainly of the engines. By February of 1895
Langley reported that under favourable conditions a lift of nearly
sixty per cent of the flying weight was secured, but although this was
much more than was required for flight, it was decided to postpone
trials until two machines were ready for the test. May, 1896, came
before actual trials were made, when one machine proved successful and
another, a later design, failed. The difficulty with these models was
that of securing a correct angle for launching; Langley records how, on
launching one machine, it rose so rapidly that it attained an angle of
sixty degrees and then did a tail slide into the water with its engines
working at full speed, after advancing nearly forty feet and remaining
in the air for about three seconds. Here, Langley found that he had
to obtain greater rigidity in his wings, owing to the distortion of
the form of wing under pressure, and how he overcame this difficulty
constitutes yet another story too long for the telling here.
Field trials were first attempted in 1893, and Langley blamed his
launching apparatus for their total failure. There was a brief, but at
the same time practical, success in model flight in 1894, extending
to between six and seven seconds, but this only proved the need for
strengthening of the wing. In 1895 there was practically no advance
toward the solution of the problem, but the flights of May 6th and
November 28th, 1896, were notably successful. A diagram given in
Langley’s memoir shows the track covered by the aerodrome on these two
flights; in the first of them the machine made three complete circles,
covering a distance of 3,200 feet; in the second, that of November
28th, the distance covered was 4,200 feet, or about three-quarters of a
mile, at a speed of about thirty miles an hour.
These achievements meant a good deal; they proved mechanically
propelled flight possible. The difference between them and such
experiments as were conducted by Clement Ader, Maxim, and others,
lay principally in the fact that these latter either did or did not
succeed in rising into the air once, and then, either willingly or by
compulsion, gave up the quest, while Langley repeated his experiments
and thus attained to actual proof of the possibilities of flight.
Like these others, however, he decided in 1896 that he would not
undertake the construction of a large man-carrying machine. In addition
to a multitude of actual duties, which left him practically no time
available for original research, he had as an adverse factor fully
ten years of disheartening difficulties in connection with his model
machines. It was President McKinley who, by requesting Langley to
undertake the construction and test of a machine which might finally
lead to the development of a flying machine capable of being used in
warfare, egged him on to his final experiment. Langley’s acceptance
of the offer to construct such a machine is contained in a letter
addressed from the Smithsonian Institution on December 12th, 1898,
to the Board of Ordnance and Fortification of the United States War
Department; this letter is of such interest as to render it worthy of
reproduction:--
‘Gentlemen,--In response to your invitation I repeat what I had the
honour to say to the Board--that I am willing, with the consent of
the Regents of this Institution, to undertake for the Government the
further investigation of the subject of the construction of a flying
machine on a scale capable of carrying a man, the investigation to
include the construction, development and test of such a machine under
conditions left as far as practicable in my discretion, it being
understood that my services are given to the Government in such time
as may not be occupied by the business of the Institution, and without
charge.
‘I have reason to believe that the cost of the construction will come
within the sum of $50,000·00, and that not more than one-half of that
will be called for in the coming year.
‘I entirely agree with what I understand to be the wish of the Board
that privacy be observed with regard to the work, and only when it
reaches a successful completion shall I wish to make public the fact of
its success.
‘I attach to this a memorandum of my understanding of some points of
detail in order to be sure that it is also the understanding of the
Board, and I am, gentlemen, with much respect, your obedient servant,
S. P. Langley.’
One of the chief problems in connection with the construction of
a full-sized apparatus was that of the construction of an engine,
for it was realised from the first that a steam power plant for a
full-sized machine could only be constructed in such a way as to make
it a constant menace to the machine which it was to propel. By this
time (1898) the internal combustion engine had so far advanced as
to convince Langley that it formed the best power plant available.
A contract was made for the delivery of a twelve horse-power engine
to weigh not more than a hundred pounds, but this contract was never
completed, and it fell to Charles M. Manly to design the five-cylinder
radial engine, of which a brief account is included in the section of
this work devoted to aero engines, as the power plant for the Langley
machine.
The history of the years 1899 to 1903 in the Langley series of
experiments contains a multitude of detail far beyond the scope of
this present study, and of interest mainly to the designer. There were
frames, engines, and propellers, to be considered, worked out, and
constructed. We are concerned here mainly with the completed machine
and its trials. Of these latter it must be remarked that the only two
actual field trials which took place resulted in accidents due to
the failure of the launching apparatus, and not due to any inherent
defect in the machine. It was intended that these two trials should
be the first of a series, but the unfortunate accidents, and the fact
that no further funds were forthcoming for continuance of experiments,
prevented Langley’s success, which, had he been free to go through as
he intended with his work, would have been certain.
The best brief description of the Langley aerodrome in its final form,
and of the two attempted trials, is contained in the official report of
Major M. M. Macomb of the United States Artillery Corps, which report
is here given in full:--
REPORT
Experiments with working models which were concluded August 8 last
having proved the principles and calculations on which the design
of the Langley aerodrome was based to be correct, the next step
was to apply these principles to the construction of a machine
of sufficient size and power to permit the carrying of a man,
who could control the motive power and guide its flight, thus
pointing the way to attaining the final goal of producing a machine
capable of such extensive and precise aerial flight, under normal
atmospheric conditions, as to prove of military or commercial
utility.
Mr C. M. Manly, working under Professor Langley, had, by the summer
of 1903, succeeded in completing an engine-driven machine which
under favourable atmospheric conditions was expected to carry a man
for any time up to half an hour, and to be capable of having its
flight directed and controlled by him.
The supporting surface of the wings was ample, and experiment
showed the engine capable of supplying more than the necessary
motive power.
Owing to the necessity of lightness, the weight of the various
elements had to be kept at a minimum, and the factor of safety in
construction was therefore exceedingly small, so that the machine
as a whole was delicate and frail and incapable of sustaining any
unusual strain. This defect was to be corrected in later models
by utilising data gathered in future experiments under varied
conditions.
One of the most remarkable results attained was the production of a
gasoline engine furnishing over fifty continuous horse-power for a
weight of 120 lbs.
The aerodrome, as completed and prepared for test, is briefly
described by Professor Langley as ‘built of steel, weighing
complete about 730 lbs., supported by 1,040 feet of sustaining
surface, having two propellers driven by a gas engine developing
continuously over fifty brake horse-power.’
The appearance of the machine prepared for flight was exceedingly
light and graceful, giving an impression to all observers of being
capable of successful flight.
On October 7 last everything was in readiness, and I witnessed the
attempted trial on that day at Widewater, Va., on the Potomac. The
engine worked well and the machine was launched at about 12.15 p.m.
The trial was unsuccessful because the front guy-post caught in
its support on the launching car and was not released in time to
give free flight, as was intended, but, on the contrary, caused the
front of the machine to be dragged downward, bending the guy-post
and making the machine plunge into the water about fifty yards in
front of the house-boat. The machine was subsequently recovered
and brought back to the house-boat. The engine was uninjured and
the frame only slightly damaged, but the four wings and rudder were
practically destroyed by the first plunge and subsequent towing
back to the house-boat. This accident necessitated the removal of
the house-boat to Washington for the more convenient repair of
damages.
On December 8 last, between 4 and 5 p.m., another attempt at a
trial was made, this time at the junction of the Anacostia with the
Potomac, just below Washington Barracks.
On this occasion General Randolph and myself represented the Board
of Ordnance and Fortification. The launching car was released at
4.45 p.m. being pointed up the Anacostia towards the Navy Yard. My
position was on the tug _Bartholdi_, about 150 feet from and at
right angles to the direction of proposed flight. The car was set
in motion and the propellers revolved rapidly, the engine working
perfectly, but there was something wrong with the launching. The
rear guy-post seemed to drag, bringing the rudder down on the
launching ways, and a crashing, rending sound, followed by the
collapse of the rear wings, showed that the machine had been
wrecked in the launching, just how, it was impossible for me to
see. The fact remains that the rear wings and rudder were wrecked
before the machine was free of the ways. Their collapse deprived
the machine of its support in the rear, and it consequently reared
up in front under the action of the motor, assumed a vertical
position, and then toppled over to the rear, falling into the water
a few feet in front of the boat.
Mr Manly was pulled out of the wreck uninjured and the wrecked
machine was subsequently placed upon the house-boat, and the whole
brought back to Washington.
From what has been said it will be seen that these unfortunate
accidents have prevented any test of the apparatus in free flight,
and the claim that an engine-driven, man-carrying aerodrome has
been constructed lacks the proof which actual flight alone can give.
Having reached the present stage of advancement in its development,
it would seem highly desirable, before laying down the
investigation, to obtain conclusive proof of the possibility of
free flight, not only because there are excellent reasons to hope
for success, but because it marks the end of a definite step toward
the attainment of the final goal.
Just what further procedure is necessary to secure successful
flight with the large aerodrome has not yet been decided upon.
Professor Langley is understood to have this subject under
advisement, and will doubtless inform the Board of his final
conclusions as soon as practicable.
In the meantime, to avoid any possible misunderstanding, it should
be stated that even after a successful test of the present great
aerodrome, designed to carry a man, we are still far from the
ultimate goal, and it would seem as if years of constant work and
study by experts, together with the expenditure of thousands of
dollars, would still be necessary before we can hope to produce
an apparatus of practical utility on these lines.--Washington,
_January 6, 1904._
[Illustration: Dynamometer tests of engine built in the Smithsonian
shops for the full-size Langley Aerodrome.
Langley Memoir on Mechanical Flight, Smithsonian Institution,
Washington.]
A subsequent report of the Board of Ordnance and Fortification to the
Secretary of War embodied the principal points in Major Macomb’s
report, but as early as March 3rd, 1904, the Board came to a similar
conclusion to that of the French Ministry of War in respect of
Clement Ader’s work, stating that it was not ‘prepared to make an
additional allotment at this time for continuing the work.’ This
decision was in no small measure due to hostile newspaper criticisms.
Langley, in a letter to the press explaining his attitude, stated
that he did not wish to make public the results of his work till
these were certain, in consequence of which he refused admittance to
newspaper representatives, and this attitude produced a hostility
which had effect on the United States Congress. An offer was made
to commercialise the invention, but Langley steadfastly refused it.
Concerning this, Manly remarks that Langley had ‘given his time and his
best labours to the world without hope of remuneration, and he could
not bring himself, at his stage of life, to consent to capitalise his
scientific work.’
The final trial of the Langley aerodrome was made on December 8 th,
1903; nine days later, on December 17th, the Wright Brothers made their
first flight in a power-propelled machine, and the conquest of the air
was thus achieved. But for the two accidents that spoilt his trials,
the honour which fell to the Wright Brothers would, beyond doubt, have
been secured by Samuel Pierpoint Langley.
XI
THE WRIGHT BROTHERS
Such information as is given here concerning the Wright Brothers is
derived from the two best sources available, namely, the writings of
Wilbur Wright himself, and a lecture given by Dr Griffith Brewer to
members of the Royal Aeronautical Society. There is no doubt that so
far as actual work in connection with aviation accomplished by the two
brothers is concerned, Wilbur Wright’s own statements are the clearest
and best available. Apparently Wilbur was, from the beginning, the
historian of the pair, though he himself would have been the last
to attempt to detract in any way from the fame that his brother’s
work also deserves. Throughout all their experiments the two were
inseparable, and their work is one indivisible whole; in fact, in every
department of that work, it is impossible to say where Orville leaves
off and where Wilbur begins.
It is a great story, this of the Wright Brothers, and one worth all the
detail that can be spared it. It begins on the 16th April, 1867, when
Wilbur Wright was born within eight miles of Newcastle, Indiana. Before
Orville’s birth on the 19th August, 1871, the Wright family had moved
to Dayton, Ohio, and settled on what is known as the ‘West Side’ of the
town. Here the brothers grew up, and, when Orville was still a boy in
his teens, he started a printing business, which, as Griffith Brewer
remarks, was only limited by the smallness of his machine and small
quantity of type at his disposal. This machine was in such a state that
pieces of string and wood were incorporated in it by way of repair, but
on it Orville managed to print a boys’ paper which gained considerable
popularity in Dayton ‘West Side.’ Later, at the age of seventeen, he
obtained a more efficient outfit, with which he launched a weekly
newspaper, four pages in size, entitled _The West Side News_. After
three months’ running the paper was increased in size and Wilbur came
into the enterprise as editor, Orville remaining publisher. In 1894 the
two brothers began the publication of a weekly magazine, _Snap-Shots_,
to which Wilbur contributed a series of articles on local affairs that
gave evidence of the incisive and often sarcastic manner in which he
was able to express himself throughout his life. Dr Griffith Brewer
describes him as a fearless critic, who wrote on matters of local
interest in a kindly but vigorous manner, which did much to maintain
the healthy public municipal life of Dayton.
Editorial and publishing enterprise was succeeded by the formation,
just across the road from the printing works, of the Wright Cycle
Company, where the two brothers launched out as cycle manufacturers
with the ‘Van Cleve’ bicycle, a machine of great local repute for
excellence of construction, and one which won for itself a reputation
that lasted long after it had ceased to be manufactured. The name of
the machine was that of an ancestor of the brothers, Catherine Van
Cleve, who was one of the first settlers at Dayton, landing there from
the River Miami on April 1st, 1796, when the country was virgin forest.
It was not until 1896 that the mechanical genius which characterised
the two brothers was turned to the consideration of aeronautics.
In that year they took up the problem thoroughly, studying all the
aeronautical information then in print. Lilienthal’s writings formed
one basis for their studies, and the work of Langley assisted in
establishing in them a confidence in the possibility of a solution to
the problems of mechanical flight. In 1909, at the banquet given by
the Royal Aero Club to the Wright Brothers on their return to America,
after the series of demonstration flights carried out by Wilbur Wright
on the Continent, Wilbur paid tribute to the great pioneer work of
Stringfellow, whose studies and achievements influenced his own and
Orville’s early work. He pointed out how Stringfellow devised an
aeroplane having two propellers and vertical and horizontal steering,
and gave due place to this early pioneer of mechanical flight.
Neither of the brothers was content with mere study of the work of
others. They collected all the theory available in the books published
up to that time, and then built man-carrying gliders with which
to test the data of Lilienthal and such other authorities as they
had consulted. For two years they conducted outdoor experiments in
order to test the truth or otherwise of what were enunciated as the
principles of flight; after this they turned to laboratory experiments,
constructing a wind tunnel in which they made thousands of tests with
models of various forms of curved planes. From their experiments they
tabulated thousands of readings, which Griffith Brewer remarks as
giving results equally efficient with those of the elaborate tables
prepared by learned institutions.
Wilbur Wright has set down the beginnings of the practical experiments
made by the two brothers very clearly. ‘The difficulties,’ he says,
‘which obstruct the pathway to success in flying machine construction
are of three general classes: (1) Those which relate to the
construction of the sustaining wings; (2) those which relate to the
generation and application of the power required to drive the machine
through the air; (3) those relating to the balancing and steering of
the machine after it is actually in flight. Of these difficulties
two are already to a certain extent solved. Men already know how to
construct wings, or aeroplanes, which, when driven through the air
at sufficient speed, will not only sustain the weight of the wings
themselves, but also that of the engine and the engineer as well. Men
also know how to build engines and screws of sufficient lightness and
power to drive these planes at sustaining speed. Inability to balance
and steer still confronts students of the flying problem, although
nearly ten years have passed (since Lilienthal’s success). When this
one feature has been worked out, the age of flying machines will have
arrived, for all other difficulties are of minor importance.
‘The person who merely watches the flight of a bird gathers the
impression that the bird has nothing to think of but the flapping of
its wings. As a matter of fact, this is a very small part of its mental
labour. Even to mention all the things the bird must constantly keep in
mind in order to fly securely through the air would take a considerable
time. If I take a piece of paper and, after placing it parallel with
the ground, quickly let it fall, it will not settle steadily down
as a staid, sensible piece of paper ought to do, but it insists on
contravening every recognised rule of decorum, turning over and darting
hither and thither in the most erratic manner, much after the style of
an untrained horse. Yet this is the style of steed that men must learn
to manage before flying can become an everyday sport. The bird has
learned this art of equilibrium, and learned it so thoroughly that its
skill is not apparent to our sight. We only learn to appreciate it when
we can imitate it.
‘Now, there are only two ways of learning to ride a fractious horse:
one is to get on him and learn by actual practice how each motion and
trick may be best met; the other is to sit on a fence and watch the
beast awhile, and then retire to the house and at leisure figure out
the best way of overcoming his jumps and kicks. The latter system
is the safer, but the former, on the whole, turns out the larger
proportion of good riders. It is very much the same in learning to ride
a flying machine; if you are looking for perfect safety you will do
well to sit on a fence and watch the birds, but if you really wish to
learn you must mount a machine and become acquainted with its tricks
by actual trial. The balancing of a gliding or flying machine is very
simple in theory. It merely consists in causing the centre of pressure
to coincide with the centre of gravity.’
[Illustration: Wilbur Wright.]
These comments are taken from a lecture delivered by Wilbur Wright
before the Western Society of Engineers in September of 1901, under
the presidency of Octave Chanute. In that lecture Wilbur detailed
the way in which he and his brother came to interest themselves in
aeronautical problems and constructed their first glider. He speaks of
his own notice of the death of Lilienthal in 1896, and of the way in
which this fatality roused him to an active interest in aeronautical
problems, which was stimulated by reading Professor Marey’s _Animal
Mechanism_, not for the first time. ‘From this I was led to read more
modern works, and as my brother soon became equally interested with
myself, we soon passed from the reading to the thinking, and finally
to the working stage. It seemed to us that the main reason why the
problem had remained so long unsolved was that no one had been able
to obtain any adequate practice. We figured that Lilienthal in five
years of time had spent only about five hours in actual gliding
through the air. The wonder was not that he had done so little, but
that he had accomplished so much. It would not be considered at all
safe for a bicycle rider to attempt to ride through a crowded city
street after only five hours’ practice, spread out in bits of ten
seconds each over a period of five years; yet Lilienthal with this
brief practice was remarkably successful in meeting the fluctuations
and eddies of wind-gusts. We thought that if some method could be
found by which it would be possible to practise by the hour instead
of by the second there would be hope of advancing the solution of a
very difficult problem. It seemed feasible to do this by building a
machine which would be sustained at a speed of eighteen miles per
hour, and then finding a locality where winds of this velocity were
common. With these conditions a rope attached to the machine to keep
it from floating backward would answer very nearly the same purpose as
a propeller driven by a motor, and it would be possible to practise by
the hour, and without any serious danger, as it would not be necessary
to rise far from the ground, and the machine would not have any forward
motion at all. We found, according to the accepted tables of air
pressure on curved surfaces, that a machine spreading 200 square feet
of wing surface would be sufficient for our purpose, and that places
would easily be found along the Atlantic coast where winds of sixteen
to twenty-five miles were not at all uncommon. When the winds were low
it was our plan to glide from the tops of sandhills, and when they were
sufficiently strong to use a rope for our motor and fly over one spot.
Our next work was to draw up the plans for a suitable machine. After
much study we finally concluded that tails were a source of trouble
rather than of assistance, and therefore we decided to dispense with
them altogether. It seemed reasonable that if the body of the operator
could be placed in a horizontal position instead of the upright, as in
the machines of Lilienthal, Pilcher, and Chanute, the wind resistance
could be very materially reduced, since only one square foot instead
of five would be exposed. As a full half horse-power would be saved
by this change, we arranged to try at least the horizontal position.
Then the method of control used by Lilienthal, which consisted in
shifting the body, did not seem quite as quick or effective as the
case required; so, after long study, we contrived a system consisting
of two large surfaces on the Chanute double-deck plan, and a smaller
surface placed a short distance in front of the main surfaces in such a
position that the action of the wind upon it would counterbalance the
effect of the travel of the centre of pressure on the main surfaces.
Thus changes in the direction and velocity of the wind would have
little disturbing effect, and the operator would be required to attend
only to the steering of the machine, which was to be effected by
curving the forward surface up or down. The lateral equilibrium and
the steering to right or left was to be attained by a peculiar torsion
of the main surfaces, which was equivalent to presenting one end of
the wings at a greater angle than the other. In the main frame a few
changes were also made in the details of construction and trussing
employed by Mr Chanute. The most important of these were: (1) The
moving of the forward main crosspiece of the frame to the extreme front
edge; (2) the encasing in the cloth of all crosspieces and ribs of the
surfaces; (3) a rearrangement of the wires used in trussing the two
surfaces together, which rendered it possible to tighten all the wires
by simply shortening two of them.’
The brothers intended originally to get 200 square feet of supporting
surface for their glider, but the impossibility of obtaining suitable
material compelled them to reduce the area to 165 square feet, which,
by the Lilienthal tables, admitted of support in a wind of about
twenty-one miles an hour at an angle of three degrees. With this glider
they went in the summer of 1900 to the little settlement of Kitty
Hawk, North Carolina, situated on the strip of land dividing Albemarle
Sound from the Atlantic. Here they reckoned on obtaining steady wind,
and here, on the day that they completed the machine, they took it
out for trial as a kite with the wind blowing at between twenty-five
and thirty miles an hour. They found that in order to support a man
on it the glider required an angle nearer twenty degrees than three,
and even with the wind at thirty miles an hour they could not get down
to the planned angle of three degrees. Later, when the wind was too
light to support the machine with a man on it, they tested it as a
kite, working the rudders by cords. Although they obtained satisfactory
results in this way they realised fully that actual gliding experience
was necessary before the tests could be considered practical.
A series of actual measurements of lift and drift of the machine gave
astonishing results. ‘It appeared that the total horizontal pull of
the machine, while sustaining a weight of 52 lbs., was only 8.5 lbs.,
which was less than had been previously estimated for head resistance
of the framing alone. Making allowance for the weight carried, it
appeared that the head resistance of the framing was but little more
than fifty per cent of the amount which Mr Chanute had estimated
as the head resistance of the framing of his machine. On the other
hand, it appeared sadly deficient in lifting power as compared with
the calculated lift of curved surfaces of its size ... we decided
to arrange our machine for the following year so that the depth of
curvature of its surfaces could be varied at will, and its covering
air-proofed.’
After these experiments the brothers decided to turn to practical
gliding, for which they moved four miles to the south, to the Kill
Devil sandhills, the principal of which is slightly over a hundred
feet in height, with an inclination of nearly ten degrees on its main
north-western slope. On the day after their arrival they made about a
dozen glides, in which, although the landings were made at a speed of
more than twenty miles an hour, no injury was sustained either by the
machine or by the operator.
‘The slope of the hill was 9.5 degrees, or a drop of one foot in six.
We found that after attaining a speed of about twenty-five to thirty
miles with reference to the wind, or ten to fifteen miles over the
ground, the machine not only glided parallel to the slope of the hill,
but greatly increased its speed, thus indicating its ability to glide
on a somewhat less angle than 9.5 degrees, when we should feel it safe
to rise higher from the surface. The control of the machine proved even
better than we had dared to expect, responding quickly to the slightest
motion of the rudder. With these glides our experiments for the year
1900 closed. Although the hours and hours of practice we had hoped to
obtain finally dwindled down to about two minutes, we were very much
pleased with the general results of the trip, for, setting out as we
did with almost revolutionary theories on many points and an entirely
untried form of machine, we considered it quite a point to be able
to return without having our pet theories completely knocked on the
head by the hard logic of experience, and our own brains dashed out
in the bargain. Everything seemed to us to confirm the correctness of
our original opinions: (1) That practice is the key to the secret of
flying; (2) that it is practicable to assume the horizontal position;
(3) that a smaller surface set at a negative angle in front of the main
bearing surfaces, or wings, will largely counteract the effect of the
fore and aft travel of the centre of pressure; (4) that steering up and
down can be attained with a rudder without moving the position of the
operator’s body; (5) that twisting the wings so as to present their
ends to the wind at different angles is a more prompt and efficient
way of maintaining lateral equilibrium than shifting the body of the
operator.’
[Illustration: Wilbur Wright in a high glide, 1903.]
[Illustration: Orville Wright making the world’s record in gliding
flight, 10 minutes 1 second, stationary against a wind of 25 miles per
hour, east of Kill Devil Hill.]
For the gliding experiments of 1901 it was decided to retain the form
of the 1900 glider, but to increase the area to 308 square feet,
which, the brothers calculated, would support itself and its operator
in a wind of seventeen miles an hour with an angle of incidence of
three degrees. Camp was formed at Kitty Hawk in the middle of July, and
on July 27th the machine was completed and tried for the first time in
a wind of about fourteen miles an hour. The first attempt resulted in
landing after a glide of only a few yards, indicating that the centre
of gravity was too far in front of the centre of pressure. By shifting
his position farther and farther back the operator finally achieved an
undulating flight of a little over 300 feet, but to obtain this success
he had to use full power of the rudder to prevent both stalling and
nose-diving. With the 1900 machine one-fourth of the rudder action had
been necessary for far better control.
Practically all glides gave the same result, and in one the machine
rose higher and higher until it lost all headway. ‘This was the
position from which Lilienthal had always found difficulty in
extricating himself, as his machine then, in spite of his greatest
exertions, manifested a tendency to dive downward almost vertically
and strike the ground head on with frightful velocity. In this case
a warning cry from the ground caused the operator to turn the rudder
to its full extent and also to move his body slightly forward. The
machine then settled slowly to the ground, maintaining its horizontal
position almost perfectly, and landed without any injury at all. This
was very encouraging, as it showed that one of the very greatest
dangers in machines with horizontal tails had been overcome by the
use of the front rudder. Several glides later the same experience was
repeated with the same result. In the latter case the machine had even
commenced to move backward, but was nevertheless brought safely to the
ground in a horizontal position. On the whole this day’s experiments
were encouraging, for while the action of the rudder did not seem
at all like that of our 1900 machine, yet we had escaped without
difficulty from positions which had proved very dangerous to preceding
experimenters, and after less than one minute’s actual practice had
made a glide of more than 300 feet, at an angle of descent of ten
degrees, and with a machine nearly twice as large as had previously
been considered safe. The trouble with its control, which has been
mentioned, we believed could be corrected when we should have located
its cause.’
It was finally ascertained that the defect could be remedied by
trussing down the ribs of the whole machine so as to reduce the depth
of curvature. When this had been done gliding was resumed, and after a
few trials glides of 366 and 389 feet were made with prompt response
on the part of the machine, even to small movements of the rudder.
The rest of the story of the gliding experiments of 1901 cannot be
better told than in Wilbur Wright’s own words, as uttered by him in the
lecture from which the foregoing excerpts have been made.
‘The machine, with its new curvature, never failed to respond promptly
to even small movements of the rudder. The operator could cause it
to almost skim the ground, following the undulations of its surface,
or he could cause it to sail out almost on a level with the starting
point, and, passing high above the foot of the hill, gradually settle
down to the ground. The wind on this day was blowing eleven to fourteen
miles per hour. The next day, the conditions being favourable, the
machine was again taken out for trial. This time the velocity of the
wind was eighteen to twenty-two miles per hour. At first we felt some
doubt as to the safety of attempting free flight in so strong a wind,
with a machine of over 300 square feet and a practice of less than
five minutes spent in actual flight. But after several preliminary
experiments we decided to try a glide. The control of the machine
seemed so good that we then felt no apprehension in sailing boldly
forth. And thereafter we made glide after glide, sometimes following
the ground closely and sometimes sailing high in the air. Mr Chanute
had his camera with him and took pictures of some of these glides,
several of which are among those shown.
‘We made glides on subsequent days, whenever the conditions were
favourable. The highest wind thus experimented in was a little over
twelve metres per second--nearly twenty-seven miles per hour.
‘It had been our intention when building the machine to do the larger
part of the experimenting in the following manner:--When the wind
blew seventeen miles an hour, or more, we would attach a rope to the
machine and let it rise as a kite with the operator upon it. When it
should reach a proper height the operator would cast off the rope and
glide down to the ground just as from the top of a hill. In this way we
would be saved the trouble of carrying the machine uphill after each
glide, and could make at least ten glides in the time required for one
in the other way. But when we came to try it, we found that a wind
of seventeen miles, as measured by Richards’ anemometer, instead of
sustaining the machine with its operator, a total weight of 240 lbs.,
at an angle of incidence of three degrees, in reality would not sustain
the machine alone--100 lbs.--at this angle. Its lifting capacity seemed
scarcely one-third of the calculated amount. In order to make sure that
this was not due to the porosity of the cloth, we constructed two small
experimental surfaces of equal size, one of which was air-proofed and
the other left in its natural state; but we could detect no difference
in their lifting powers. For a time we were led to suspect that the
lift of curved surfaces very little exceeded that of planes of the same
size, but further investigation and experiment led to the opinion that
(1) the anemometer used by us over-recorded the true velocity of the
wind by nearly 15 per cent; (2) that the well-known Smeaton coefficient
of .005 V² for the wind pressure at 90 degrees is probably too great
by at least 20 per cent; (3) that Lilienthal’s estimate that the
pressure on a curved surface having an angle of incidence of 3 degrees
equals .545 of the pressure at 90 degrees is too large, being nearly
50 per cent greater than very recent experiments of our own with a
pressure testing-machine indicate; (4) that the superposition of the
surfaces somewhat reduced the lift per square foot, as compared with a
single surface of equal area.
‘In gliding experiments, however, the amount of lift is of less
relative importance than the ratio of lift to drift, as this alone
decides the angle of gliding descent. In a plane the pressure is
always perpendicular to the surface, and the ratio of lift to drift
is therefore the same as that of the cosine to the sine of the angle
of incidence. But in curved surfaces a very remarkable situation
is found. The pressure, instead of being uniformly normal to the
chord of the arc, is usually inclined considerably in front of the
perpendicular. The result is that the lift is greater and the drift
less than if the pressure were normal. Lilienthal was the first to
discover this exceedingly important fact, which is fully set forth
in his book, _Bird Flight the Basis of the Flying Art_, but owing to
some errors in the methods he used in making measurements, question
was raised by other investigators not only as to the accuracy of his
figures, but even as to the existence of any tangential force at
all. Our experiments confirm the existence of this force, though our
measurements differ considerably from those of Lilienthal. While at
Kitty Hawk we spent much time in measuring the horizontal pressure on
our unloaded machine at various angles of incidence. We found that at
13 degrees the horizontal pressure was about 23 lbs. This included not
only the drift proper, or horizontal component of the pressure on the
side of the surface, but also the head resistance of the framing as
well. The weight of the machine at the time of this test was about 108
lbs. Now, if the pressure had been normal to the chord of the surface,
the drift proper would have been to the lift (108 lbs.) as the sine
of 13 degrees is to the cosine of 13 degrees, or (.22 × 108) / .97 =
24 + lbs.; but this slightly exceeds the total pull of 23 pounds on
our scales. Therefore it is evident that the average pressure on the
surface, instead of being normal to the chord, was so far inclined
toward the front that all the head resistance of framing and wires
used in the construction was more than overcome. In a wind of fourteen
miles per hour resistance is by no means a negligible factor, so that
tangential is evidently a force of considerable value. In a higher
wind, which sustained the machine at an angle of 10 degrees the pull
on the scales was 18 lbs. With the pressure normal to the chord the
drift proper would have been (17 × 98) / ·98. The travel of the centre
of pressure made it necessary to put sand on the front rudder to bring
the centres of gravity and pressure into coincidence, consequently the
weight of the machine varied from 98 lbs. to 108 lbs. in the different
tests) = 17 lbs., so that, although the higher wind velocity must
have caused an increase in the head resistance, the tangential force
still came within 1 lb. of overcoming it. After our return from Kitty
Hawk we began a series of experiments to accurately determine the
amount and direction of the pressure produced on curved surfaces when
acted upon by winds at the various angles from zero to 90 degrees.
These experiments are not yet concluded, but in general they support
Lilienthal in the claim that the curves give pressures more favourable
in amount and direction than planes; but we find marked differences
in the exact values, especially at angles below 10 degrees. We were
unable to obtain direct measurements of the horizontal pressures of
the machine with the operator on board, but by comparing the distance
travelled with the vertical fall, it was easily calculated that at a
speed of 24 miles per hour the total horizontal resistances of our
machine, when bearing the operator, amounted to 40 lbs, which is
equivalent to about 2⅓ horse-power. It must not be supposed, however,
that a motor developing this power would be sufficient to drive a
man-bearing machine. The extra weight of the motor would require either
a larger machine, higher speed, or a greater angle of incidence in
order to support it, and therefore more power. It is probable, however,
that an engine of 6 horse-power, weighing 100 lbs. would answer the
purpose. Such an engine is entirely practicable. Indeed, working motors
of one-half this weight per horse-power (9 lbs. per horse-power) have
been constructed by several different builders. Increasing the speed of
our machine from 24 to 33 miles per hour reduced the total horizontal
pressure from 40 to about 35 lbs. This was quite an advantage in
gliding, as it made it possible to sail about 15 per cent farther
with a given drop. However, it would be of little or no advantage in
reducing the size of the motor in a power-driven machine, because the
lessened thrust would be counterbalanced by the increased speed per
minute. Some years ago Professor Langley called attention to the great
economy of thrust which might be obtained by using very high speeds,
and from this many were led to suppose that high speed was essential to
success in a motor-driven machine. But the economy to which Professor
Langley called attention was in foot pounds per mile of travel, not in
foot pounds per minute. It is the foot pounds per minute that fixes the
size of the motor. The probability is that the first flying machines
will have a relatively low speed, perhaps not much exceeding 20 miles
per hour, but the problem of increasing the speed will be much simpler
in some respects than that of increasing the speed of a steamboat;
for, whereas in the latter case the size of the engine must increase
as the cube of the speed, in the flying machine, until extremely high
speeds are reached, the capacity of the motor increases in less than
simple ratio; and there is even a decrease in the fuel per mile of
travel. In other words, to double the speed of a steamship (and the
same is true of the balloon type of airship) eight times the engine and
boiler capacity would be required, and four times the fuel consumption
per mile of travel; while a flying machine would require engines of
less than double the size, and there would be an actual decrease in
the fuel consumption per mile of travel. But looking at the matter
conversely, the great disadvantage of the flying machine is apparent;
for in the latter no flight at all is possible unless the proportion
of horse-power to flying capacity is very high; but on the other hand
a steamship is a mechanical success if its ratio of horse-power to
tonnage is insignificant. A flying machine that would fly at a speed
of 50 miles per hour with engines of 1,000 horse-power would not be
upheld by its wings at all at a speed of less than 25 miles an hour,
and nothing less than 500 horse-power could drive it at this speed.
But a boat which could make 40 miles an hour with engines of 1,000
horse-power would still move 4 miles an hour even if the engines were
reduced to 1 horse-power. The problems of land and water travel were
solved in the nineteenth century, because it was possible to begin
with small achievements, and gradually work up to our present success.
The flying problem was left over to the twentieth century, because in
this case the art must be highly developed before any flight of any
considerable duration at all can be obtained.
‘However, there is another way of flying which requires no artificial
motor, and many workers believe that success will come first by
this road. I refer to the soaring flight, by which the machine is
permanently sustained in the air by the same means that are employed
by soaring birds. They spread their wings to the wind, and sail by the
hour, with no perceptible exertion beyond that required to balance
and steer themselves. What sustains them is not definitely known,
though it is almost certain that it is a rising current of air. But
whether it be a rising current or something else, it is as well able
to support a flying machine as a bird, if man once learns the art of
utilising it. In gliding experiments it has long been known that the
rate of vertical descent is very much retarded, and the duration of
the flight greatly prolonged, if a strong wind blows _up_ the face of
the hill parallel to its surface. Our machine, when gliding in still
air, has a rate of vertical descent of nearly 6 feet per second, while
in a wind blowing 26 miles per hour up a steep hill we made glides in
which the rate of descent was less than 2 feet per second. And during
the larger part of this time, while the machine remained exactly in the
rising current, _there was no descent at all, but even a slight rise_.
If the operator had had sufficient skill to keep himself from passing
beyond the rising current he would have been sustained indefinitely
at a higher point than that from which he started. The illustration
shows one of these very slow glides at a time when the machine was
practically at a standstill. The failure to advance more rapidly caused
the photographer some trouble in aiming, as you will perceive. In
looking at this picture you will readily understand that the excitement
of gliding experiments does not entirely cease with the breaking up
of camp. In the photographic dark-room at home we pass moments of
as thrilling interest as any in the field, when the image begins to
appear on the plate and it is yet an open question whether we have a
picture of a flying machine or merely a patch of open sky. These slow
glides in rising current probably hold out greater hope of extensive
practice than any other method within man’s reach, but they have the
disadvantage of requiring rather strong winds or very large supporting
surfaces. However, when gliding operators have attained greater skill,
they can with comparative safety maintain themselves in the air for
hours at a time in this way, and thus by constant practice so increase
their knowledge and skill that they can rise into the higher air and
search out the currents which enable the soaring birds to transport
themselves to any desired point by first rising in a circle and then
sailing off at a descending angle. This illustration shows the machine,
alone, flying in a wind of 35 miles per hour on the face of a steep
hill, 100 feet high. It will be seen that the machine not only pulls
upward, but also pulls forward in the direction from which the wind
blows, thus overcoming both gravity and the speed of the wind. We tried
the same experiment with a man on it, but found danger that the forward
pull would become so strong, that the men holding the ropes would be
dragged from their insecure foothold on the slope of the hill. So this
form of experimenting was discontinued after four or five minutes’
trial.
‘In looking over our experiments of the past two years, with models and
full-size machines, the following points stand out with clearness:--
‘1. That the lifting power of a large machine, held stationary in
a wind at a small distance from the earth, is much less than the
Lilienthal table and our own laboratory experiments would lead us to
expect. When the machine is moved through the air, as in gliding, the
discrepancy seems much less marked.
‘2. That the ratio of drift to lift in well-shaped surfaces is less at
angles of incidence of 5 degrees to 12 degrees than at an angle of 3
degrees.
‘3. That in arched surfaces the centre of pressure at 90 degrees is
near the centre of the surface, but moves slowly forward as the angle
becomes less, till a critical angle varying with the shape and depth of
the curve is reached, after which it moves rapidly toward the rear till
the angle of no lift is found.
‘4. That with similar conditions large surfaces may be controlled with
not much greater difficulty than small ones, if the control is effected
by manipulation of the surfaces themselves, rather than by a movement
of the body of the operator.
‘5. That the head resistances of the framing can be brought to a point
much below that usually estimated as necessary.
‘6. That tails, both vertical and horizontal, may with safety be
eliminated in gliding and other flying experiments.
‘7. That a horizontal position of the operator’s body may be assumed
without excessive danger, and thus the head resistance reduced to about
one-fifth that of the upright position.
‘8. That a pair of superposed, or tandem surfaces, has less lift in
proportion to drift than either surface separately, even after making
allowance for weight and head resistance of the connections.’
[Illustration: The Wrights’ first power-driven machine, 1903.]
Thus, to the end of the 1901 experiments, Wilbur Wright provided a
fairly full account of what was accomplished; the record shows an
amount of patient and painstaking work almost beyond belief--it was no
question of making a plane and launching it, but a business of trial
and error, investigation and tabulation of detail, and the rejection
time after time of previously accepted theories, till the brothers must
have felt that the solid earth was no longer secure, at times. Though
it was Wilbur who set down this and other records of the work done, yet
the actual work was so much Orville’s as his brother’s that no analysis
could separate any set of experiments and say that Orville did this
and Wilbur did that--the two were inseparable. On this point Griffith
Brewer remarked that ‘in the arguments, if one brother took one view,
the other brother took the opposite view as a matter of course, and
the subject was thrashed to pieces until a mutually acceptable result
remained. I have often been asked since these pioneer days, “Tell me,
Brewer, who was really the originator of those two?” In reply, I used
first to say, “I think it was mostly Wilbur,” and later, when I came
to know Orville better, I said, “The thing could not have been done
without Orville.” Now, when asked, I find I have to say, “I don’t
know,” and I feel the more I think of it that it was only the wonderful
combination of these two brothers, who devoted their lives together
for this common object, that made the discovery of the art of flying
possible.’
Beyond the 1901 experiments in gliding, the record grows more
scrappy, less detailed. It appears that once power-driven flight had
been achieved, the brothers were not so willing to talk as before;
considering the amount of work that they put in, there could have been
little time for verbal description of that work--as already remarked,
their tables still stand for the designer and experimenter. The end
of the 1901 experiments left both brothers somewhat discouraged,
though they had accomplished more than any others. ‘Having set out
with absolute faith in the existing scientific data, we were driven
to doubt one thing after another, till finally, after two years of
experiment, we cast it all aside, and decided to rely entirely on our
own investigations. Truth and error were everywhere so intimately mixed
as to be indistinguishable.... We had taken up aeronautics as a sport.
We reluctantly entered upon the scientific side of it.’
Yet, driven thus to the more serious aspect of the work, they found
in the step its own reward, for the work of itself drew them on and
on, to the construction of measuring machines for the avoidance of
error, and, to the making of series after series of measurements,
concerning which Wilbur wrote in 1908 (in the _Century Magazine_) that
‘after making preliminary measurements on a great number of different
shaped surfaces, to secure a general understanding of the subject,
we began systematic measurements of standard surfaces, so varied in
design as to bring out the underlying causes of differences noted in
their pressures. Measurements were tabulated on nearly fifty of these
at all angles from zero to 45 degrees, at intervals of 2½ degrees.
Measurements were also secured showing the effects on each other when
surfaces are superposed, or when they follow one another.
‘Some strange results were obtained. One surface, with a heavy roll
at the front edge, showed the same lift for all angles from 7½ to 45
degrees. This seemed so anomalous that we were almost ready to doubt
our own measurements, when a simple test was suggested. A weather vane,
with two planes attached to the pointer at an angle of 80 degrees with
each other, was made. According to our table, such a vane would be in
unstable equilibrium when pointing directly into the wind; for if by
chance the wind should happen to strike one plane at 39 degrees and
the other at 41 degrees, the plane with the smaller angle would have
the greater pressure, and the pointer would be turned still farther
out of the course of the wind until the two vanes again secured equal
pressures, which would be at approximately 30 and 50 degrees. But the
vane performed in this very manner. Further corroboration of the tables
was obtained in experiments with the new glider at Kill Devil Hill the
next season.
‘In September and October, 1902, nearly 1,000 gliding flights were
made, several of which covered distances of over 600 feet. Some, made
against a wind of 36 miles an hour, gave proof of the effectiveness of
the devices for control. With this machine, in the autumn of 1903, we
made a number of flights in which we remained in the air for over a
minute, often soaring for a considerable time in one spot, without any
descent at all. Little wonder that our unscientific assistant should
think the only thing needed to keep it indefinitely in the air would be
a coat of feathers to make it light!’
It was at the conclusion of these experiments of 1903 that the brothers
concluded they had obtained sufficient data from their thousands of
glides and multitude of calculations to permit of their constructing
and making trial of a power-driven machine. The first designs got out
provided for a total weight of 600 lbs., which was to include the
weight of the motor and the pilot; but on completion it was found that
there was a surplus of power from the motor, and thus they had 150 lbs.
weight to allow for strengthening wings and other parts.
They came up against the problem to which Riach has since devoted so
much attention, that of propeller design. ‘We had thought of getting
the theory of the screw-propeller from the marine engineers, and then,
by applying our table of air-pressures to their formulæ, of designing
air-propellers suitable for our uses. But, so far as we could learn,
the marine engineers possessed only empirical formulæ, and the exact
action of the screw propeller, after a century of use, was still very
obscure. As we were not in a position to undertake a long series
of practical experiments to discover a propeller suitable for our
machine, it seemed necessary to obtain such a thorough understanding
of the theory of its reactions as would enable us to design them from
calculation alone. What at first seemed a simple problem became more
complex the longer we studied it. With the machine moving forward,
the air flying backward, the propellers turning sidewise, and nothing
standing still, it seemed impossible to find a starting point from
which to trace the various simultaneous reactions. Contemplation of it
was confusing. After long arguments we often found ourselves in the
ludicrous position of each having been converted to the other’s side,
with no more agreement than when the discussion began.
‘It was not till several months had passed, and every phase of the
problem had been thrashed over and over, that the various reactions
began to untangle themselves. When once a clear understanding had
been obtained there was no difficulty in designing a suitable
propeller, with proper diameter, pitch, and area of blade, to meet the
requirements of the flier. High efficiency in a screw-propeller is not
dependent upon any particular or peculiar shape, and there is no such
thing as a “best” screw. A propeller giving a high dynamic efficiency
when used upon one machine may be almost worthless when used upon
another. The propeller should in every case be designed to meet the
particular conditions of the machine to which it is to be applied. Our
first propellers, built entirely from calculation, gave in useful work
66 per cent of the power expended. This was about one-third more than
had been secured by Maxim or Langley.’
Langley had made his last attempt with the ‘aerodrome,’ and his
splendid failure but a few days before the brothers made their first
attempt at power-driven aeroplane flight. On December 17th, 1903, the
machine was taken out; in addition to Wilbur and Orville Wright, there
were present five spectators: Mr A. D. Etheridge, of the Kill Devil
life-saving station; Mr W. S. Dough, Mr W. C. Brinkley, of Manteo; Mr
John Ward, of Naghead, and Mr John T. Daniels.[3] A general invitation
had been given to practically all the residents in the vicinity, but
the Kill Devil district is a cold area in December, and history had
recorded so many experiments in which machines had failed to leave the
ground that between temperature and scepticism only these five risked a
waste of their time.
[Illustration: First flight of first power-driven machine, 17th
December, 1903, near Kill Devil Hill, Kitty Hawk, N.C. Starting rail on
left. Orville Wright piloting machine.]
And these five were in at the greatest conquest man had made since
James Watt evolved the steam engine--perhaps even a greater conquest
than that of Watt. Four flights in all were made; the first lasted
only twelve seconds, ‘the first in the history of the world in which
a machine carrying a man had raised itself into the air by its own
power in free flight, had sailed forward on a level course without
reduction of speed, and had finally landed without being wrecked,’
said Wilbur Wright concerning the achievement.[4] The next two flights
were slightly longer, and the fourth and last of the day was one second
short of the complete minute; it was made into the teeth of a 20 mile
an hour wind, and the distance travelled was 852 feet.
This bald statement of the day’s doings is as Wilbur Wright himself
has given it, and there is in truth nothing more to say; no amount of
statement could add to the importance of the achievement, and no more
than the bare record is necessary. The faith that had inspired the long
roll of pioneers, from da Vinci onward, was justified at last.
Having made their conquest, the brothers took the machine back to
camp, and, as they thought, placed it in safety. Talking with the
little group of spectators about the flights, they forgot about the
machine, and then a sudden gust of wind struck it. Seeing that it
was being overturned, all made a rush toward it to save it, and Mr
Daniels, a man of large proportions, was in some way lifted off his
feet, falling between the planes. The machine overturned fully, and
Daniels was shaken like a die in a cup as the wind rolled the machine
over and over--he came out at the end of his experience with a series
of bad bruises, and no more, but the damage done to the machine by the
accident was sufficient to render it useless for further experiment
that season.
A new machine, stronger and heavier, was constructed by the brothers,
and in the spring of 1904 they began experiments again at Simms
Station, eight miles to the east of Dayton, their home town. Press
representatives were invited for the first trial, and about a dozen
came--the whole gathering did not number more than fifty people. ‘When
preparations had been concluded,’ Wilbur Wright wrote of this trial,
‘a wind of only three or four miles an hour was blowing--insufficient
for starting on so short a track--but since many had come a long way
to see the machine in action, an attempt was made. To add to the other
difficulty, the engine refused to work properly. The machine, after
running the length of the track, slid off the end without rising into
the air at all. Several of the newspaper men returned next day but were
again disappointed. The engine performed badly, and after a glide of
only sixty feet the machine again came to the ground. Further trial was
postponed till the motor could be put in better running condition. The
reporters had now, no doubt, lost confidence in the machine, though
their reports, in kindness, concealed it. Later, when they heard
that we were making flights of several minutes’ duration, knowing
that longer flights had been made with airships, and not knowing any
essential difference between airships and flying machines, they were
but little interested.
‘We had not been flying long in 1904 before we found that the problem
of equilibrium had not as yet been entirely solved. Sometimes, in
making a circle, the machine would turn over sidewise despite anything
the operator could do, although, under the same conditions in ordinary
straight flight it could have been righted in an instant. In one
flight, in 1905, while circling round a honey locust-tree at a height
of about 50 feet, the machine suddenly began to turn up on one wing,
and took a course toward the tree. The operator, not relishing the
idea of landing in a thorn tree, attempted to reach the ground. The
left wing, however, struck the tree at a height of 10 or 12 feet from
the ground and carried away several branches; but the flight, which had
already covered a distance of six miles, was continued to the starting
point.
‘The causes of these troubles--too technical for explanation here--were
not entirely overcome till the end of September, 1905. The flights then
rapidly increased in length, till experiments were discontinued after
October 5, on account of the number of people attracted to the field.
Although made on a ground open on every side, and bordered on two sides
by much-travelled thoroughfares, with electric cars passing every
hour, and seen by all the people living in the neighbourhood for miles
around, and by several hundred others, yet these flights have been made
by some newspapers the subject of a great “mystery.”’
Viewing their work from the financial side, the two brothers incurred
but little expense in the earlier gliding experiments, and, indeed,
viewed these only as recreation, limiting their expenditure to that
which two men might spend on any hobby. When they had once achieved
successful power-driven flight, they saw the possibilities of their
work, and abandoned such other business as had engaged their energies,
sinking all their capital in the development of a practical flying
machine. Having, in 1905, improved their designs to such an extent
that they could consider their machine a practical aeroplane, they
devoted the years 1906 and 1907 to business negotiations and to the
construction of new machines, resuming flying experiments in May
of 1908 in order to test the ability of their machine to meet the
requirements of a contract they had made with the United States
Government, which required an aeroplane capable of carrying two men,
together with sufficient fuel supplies for a flight of 125 miles at
40 miles per hour. Practically similar to the machine used in the
experiments of 1905, the contract aeroplane was fitted with a larger
motor, and provision was made for seating a passenger and also for
allowing of the operator assuming a sitting position, instead of lying
prone.
Before leaving the work of the brothers to consider contemporary
events, it may be noted that they claimed--with justice--that they were
first to construct wings adjustable to different angles of incidence
on the right and left side in order to control the balance of an
aeroplane; the first to attain lateral balance by adjusting wing-tips
to respectively different angles of incidence on the right and left
sides, and the first to use a vertical vane in combination with
wing-tips, adjustable to respectively different angles of incidence,
in balancing and steering an aeroplane. They were first, too, to use
a movable vertical tail, in combination with wings adjustable to
different angles of incidence, in controlling the balance and direction
of an aeroplane.[5]
A certain Henry M. Weaver, who went to see the work of the brothers,
writing in a letter which was subsequently read before the Aero Club
de France, records that he had a talk in 1905 with the farmer who
rented the field in which the Wrights made their flights. ‘On October
5th (1905) he was cutting corn in the next field east, which is higher
ground. When he noticed the aeroplane had started on its flight he
remarked to his helper: “Well, the boys are at it again,” and kept on
cutting corn, at the same time keeping an eye on the great white form
rushing about its course. “I just kept on shocking corn,” he continued,
“until I got down to the fence, and the durned thing was still going
round. I thought it would never stop.”’
He was right. The brothers started it, and it will never stop.
Mr Weaver also notes briefly the construction of the 1905 Wright flier.
‘The frame was made of larch wood--from tip to tip of the wings the
dimension was 40 feet. The gasoline motor--a special construction
made by them--much the same, though, as the motor on the Pope-Toledo
automobile--was of from 12 to 15 horse-power. The motor weighed 240
lbs. The frame was covered with ordinary muslin of good quality. No
attempt was made to lighten the machine; they simply built it strong
enough to stand the shocks. The structure stood on skids or runners,
like a sleigh. These held the frame high enough from the ground in
alighting to protect the blades of the propeller. Complete with motor,
the machine weighed 925 lbs.’
XII
THE FIRST YEARS OF CONQUEST
It is no derogation of the work accomplished by the Wright Brothers
to say that they won the honour of the first power-propelled flights
in a heavier-than-air machine only by a short period. In Europe, and
especially in France, independent experiment was being conducted by
Ferber, by Santos-Dumont, and others, while in England Cody was not far
behind the other giants of those days. The history of the early years
of controlled power flights is a tangle of half-records; there were no
chroniclers, only workers, and much of what was done goes unrecorded
perforce, since it was not set down at the time.
Before passing to survey of those early years, let it be set down that
in 1907, when the Wright Brothers had proved the practicability of
their machines, negotiations were entered into between the brothers and
the British War Office. On April 12th, 1907, the apostle of military
stagnation, Haldane, then War Minister, put an end to the negotiations
by declaring that ‘the War Office is not disposed to enter into
relations at present with any manufacturer of aeroplanes.’ The state
of the British air service in 1914, at the outbreak of hostilities, is
eloquent regarding the pursuance of the policy which Haldane initiated.
‘If I talked a lot,’ said Wilbur Wright once, ‘I should be like
the parrot, which is the bird that speaks most and flies least.’
That attitude is emblematic of the majority of the early fliers, and
because of it the record of their achievements is incomplete to-day.
Ferber, for instance, has left little from which to state what he did,
and that little is scattered through various periodicals, scrappily
enough. A French army officer, Captain Ferber was experimenting with
monoplane and biplane gliders at the beginning of the century--his work
was contemporary with that of the Wrights. He corresponded both with
Chanute and with the Wrights, and in the end he was commissioned by the
French Ministry of War to undertake the journey to America in order
to negotiate with the Wright Brothers concerning French rights in the
patents they had acquired, and to study their work at first hand.
Ferber’s experiments in gliding began in 1899 at the Military School at
Fountainebleau, with a canvas glider of some 80 square feet supporting
surface, and weighing 65 lbs. Two years later he constructed a larger
and more satisfactory machine, with which he made numerous excellent
glides. Later, he constructed an apparatus which suspended a plane from
a long arm which swung on a tower, in order that experiments might be
carried out without risk to the experimenter, and it was not until
1905 that he attempted power-driven free flight. He took up the Voisin
design of biplane for his power-driven flights, and virtually devoted
all his energies to the study of aeronautics. His book, _Aviation,
its Dawn and Development_, is a work of scientific value--unlike many
of his contemporaries, Ferber brought to the study of the problems
of flight a trained mind, and he was concerned equally with the
theoretical problems of aeronautics and the practical aspects of the
subject.
After Bleriot’s successful cross-Channel flight, it was proposed to
offer a prize of £1,000 for the feat which C. S. Rolls subsequently
accomplished (starting from the English side of the Channel), a flight
from Boulogne to Dover and back; in place of this, however, an aviation
week at Boulogne was organised, but, although numerous aviators were
invited to compete, the condition of the flying grounds was such that
no competitions took place. Ferber was virtually the only one to do any
flying at Boulogne, and at the outset he had his first accident; after
what was for those days a good flight, he made a series of circles
with his machine, when it suddenly struck the ground, being partially
wrecked. Repairs were carried out, and Ferber resumed his exhibition
flights, carrying on up to Wednesday, September 22nd, 1909. On that day
he remained in the air for half an hour, and, as he was about to land,
the machine struck a mound of earth and overturned, pinning Ferber
under the weight of the motor. After being extricated, Ferber seemed to
show little concern at the accident, but in a few minutes he complained
of great pain, when he was conveyed to the ambulance shed on the ground.
‘I was foolish,’ he told those who were with him there. ‘I was flying
too low. It was my own fault and it will be a severe lesson to me.
I wanted to turn round, and was only five metres from the ground.’
A little after this, he got up from the couch on which he had been
placed, and almost immediately collapsed, dying five minutes later.
[Illustration: Blériot in full flight.]
Ferber’s chief contemporaries in France were Santos-Dumont,
of airship fame, Henri and Maurice Farman, Hubert Latham, Ernest
Archdeacon, and Delagrange. These are names that come at once to mind,
as does that of Bleriot, who accomplished the second great feat of
power-driven flight, but as a matter of fact the years 1903–10 are
filled with a little host of investigators and experimenters, many of
whom, although their names do not survive to any extent, are but a very
little way behind those mentioned here in enthusiasm and devotion.
Archdeacon and Gabriel Voisin, the former of whom took to heart the
success achieved by the Wright Brothers, co-operated in experiments
in gliding. Archdeacon constructed a glider in box-kite fashion, and
Voisin experimented with it on the Seine, the glider being towed by a
motor-boat to attain the necessary speed. It was Archdeacon who offered
a cup for the first straight flight of 200 metres, which was won by
Santos-Dumont, and he also combined with Henri Deutsch de la Meurthe in
giving the prize for the first circular flight of a mile, which was won
by Henry Farman on January 13th, 1908.
A history of the development of aviation in France in these, the
strenuous years, would fill volumes in itself. Bleriot was carrying
out experiments with a biplane glider on the Seine, and Robert
Esnault-Pelterie was working on the lines of the Wright Brothers,
bringing American practice to France. In America others besides the
Wrights had wakened to the possibilities of heavier-than-air flight;
Glenn Curtiss, in company with Dr Alexander Graham Bell, with J. A. D.
McCurdy, and with F. W. Baldwin, a Canadian engineer, formed the Aerial
Experiment Company, which built a number of aeroplanes, most famous of
which were the ‘June Bug,’ the ‘Red Wing’ and the ‘White Wing.’ In 1908
the ‘June Bug’ won a cup presented by the _Scientific American_--it was
the first prize offered in America in connection with aeroplane flight.
Among the little group of French experimenters in these first years
of practical flight, Santos-Dumont takes high rank. He built his ‘No.
14 bis’ aeroplane in biplane form, with two superposed main plane
surfaces, and fitted it with an eight-cylinder Antoinette motor driving
a two-bladed aluminium propeller, of which the blades were 6 feet only
from tip to tip. The total lift surface of 860 square feet was given
with a wing-span of a little under 40 feet, and the weight of the
complete machine was 353 lbs., of which the engine weighed 158 lbs.
In July of 1906 Santos-Dumont flew a distance of a few yards in this
machine, but damaged it in striking the ground; on October 23rd of the
same year he made a flight of nearly 200 feet--which might have been
longer, but that he feared a crowd in front of the aeroplane and cut
off his ignition. This may be regarded as the first effective flight in
Europe, and by it Santos-Dumont takes his place as one of the chief--if
not the chief--of the pioneers of the first years of practical flight,
so far as Europe is concerned.
Meanwhile, the Voisin Brothers, who in 1904 made cellular kites for
Archdeacon to test by towing on the Seine from a motor launch, obtained
data for the construction of the aeroplane which Delagrange and Henry
Farman were to use later. The Voisin was a biplane, constructed with
due regard to the designs of Langley, Lilienthal, and other earlier
experimenters--both the Voisins and M. Colliex, their engineer,
studied Lilienthal pretty exhaustively in getting out their design,
though their own researches were very thorough as well. The weight of
this Voisin biplane was about 1,450 lbs., and its maximum speed was
some 38 to 40 miles per hour, the total supporting surface being about
535 square feet. It differed from the Wright design in the possession
of a tail-piece, a characteristic which marked all the French school
of early design as in opposition to the American. The Wright machine
got its longitudinal stability by means of the main planes and the
elevating planes, while the Voisin type added a third factor of
stability in its tail-planes. Further, the Voisins fitted their biplane
with a wheeled undercarriage, while the Wright machine, being fitted
only with runners, demanded a launching rail for starting. Whether a
machine should be tailless or tailed was for some long time matter for
acute controversy, which in the end was settled by the fitting of a
tail to the Wright machines--France won the dispute by the concession.
Henry Farman, who began his flying career with a Voisin machine,
evolved from it the aeroplane which bore his name, following the
main lines of the Voisin type fairly closely, but making alterations
in the controls, and in the design of the undercarriage, which was
somewhat elaborated, even to the inclusion of shock absorbers. The
seven-cylinder 50 horse-power Gnome rotary engine was fitted to the
Farman machine--the Voisins had fitted an eight-cylinder Antoinette,
giving 50 horse-power at 1,100 revolutions per minute, with direct
drive to the propeller. Farman reduced the weight of the machine from
the 1,450 lbs. of the Voisins to some 1,010 lbs. or thereabouts, and
the supporting area to 450 square feet. This machine won its chief fame
with Paulhan as pilot in the famous London to Manchester flight--it is
to be remarked, too, that Farman himself was the first man in Europe to
accomplish a flight of a mile.
Other notable designs of these early days were the ‘R.E.P.’, Esnault
Pelterie’s machine, and the Curtiss-Herring biplane. Of these Esnault
Pelterie’s was a monoplane, designed in that form since Esnault
Pelterie had found by experiment that the wire used in bracing offers
far more resistance to the air than its dimensions would seem to
warrant. He built the wings of sufficient strength to stand the strain
of flight without bracing wires, and dependent only for their support
on the points of attachment to the body of the machine; for the rest,
it carried its propeller in front of the planes, and both horizontal
and vertical rudders at the stern--a distinct departure from the Wright
and similar types. One wheel only was fixed under the body where the
undercarriage exists on a normal design, but light wheels were fixed,
one at the extremity of each wing, and there was also a wheel under the
tail portion of the machine. A single lever actuated all the controls
for steering. With a supporting surface of 150 square feet the machine
weighed 946 lbs., about 6.4 lbs. per square foot of lifting surface.
The Curtiss biplane, as flown by Glenn Curtiss at the Rheims meeting,
was built with a bamboo framework, stayed by means of very fine
steel-stranded cables. A--then--novel feature of the machine was the
moving of the ailerons by the pilot leaning to one side or the other in
his seat, a light, tubular arm-rest being pressed by his body when he
leaned to one side or the other, and thus operating the movement of the
ailerons employed for tilting the plane when turning. A steering-wheel
fitted immediately in front of the pilot’s seat served to operate a
rear steering-rudder when the wheel was turned in either direction,
while pulling back the wheel altered the inclination of the front
elevating planes, and so gave lifting or depressing control of the
plane.
This machine ran on three wheels before leaving the ground, a central
undercarriage wheel being fitted in front, with two more in line with
a right angle line drawn through the centre of the engine crank at
the rear end of the crank-case. The engine was a 35 horse-power Vee
design, water-cooled, with overhead inlet and exhaust valves, and Bosch
high-tension magneto ignition. The total weight of the plane in flying
order was about 700 lbs.
As great a figure in the early days as either Ferber or Santos-Dumont
was Louis Bleriot, who, as early as 1900, built a flapping-wing model,
this before ever he came to experimenting with the Voisin biplane type
of glider on the Seine. Up to 1906 he had built four biplanes of his
own design, and in March of 1907 he built his first monoplane, to wreck
it only a few days after completion in an accident from which he had
a fortunate escape. His next machine was a double monoplane, designed
after Langley’s precept, to a certain extent, and this was totally
wrecked in September of 1907. His seventh machine, a monoplane, was
built within a month of this accident, and with this he had a number of
mishaps, also achieving some good flights, including one in which he
made a turn. It was wrecked in December of 1907, whereupon he built
another monoplane on which, on July 6th, 1908, Bleriot made a flight
lasting eight and a half minutes. In October of that year he flew the
machine from Toury to Artenay and returned on it--this was just a day
after Farman’s first cross-country flight--but, trying to repeat the
success five days later, Bleriot collided with a tree in a fog and
wrecked the machine past repair. Thereupon he set about building his
eleventh machine, with which he was to achieve the first flight across
the English channel.
Henry Farman, to whom reference has already been made, was engaged
with his two brothers, Maurice and Richard, in the motor-car business,
and turned to active interest in flying in 1907, when the Voisin firm
built his first biplane on the box-kite principle. In July of 1908 he
won a prize of £400 for a flight of thirteen miles, previously having
completed the first kilometre flown in Europe with a passenger, the
said passenger being Ernest Archdeacon. In September of 1908 Farman
put up a speed record of forty miles an hour in a flight lasting forty
minutes.
Santos-Dumont produced the famous ‘Demoiselle’ monoplane early in 1909,
a tiny machine in which the pilot had his seat in a sort of miniature
cage under the main plane. It was a very fast, light little machine,
but was difficult to fly, and owing to its small wing-spread was unable
to glide at a reasonably safe angle. There has probably never been a
cheaper flying machine to build than the ‘Demoiselle,’ which could be
so upset as to seem completely wrecked, and then repaired ready for
further flight by a couple of hours’ work. Santos-Dumont retained no
patent in the design, but gave it out freely to any one who chose to
build ‘Demoiselles’; the vogue of the pattern was brief, owing to the
difficulty of piloting the machine.
These were the years of records, broken almost as soon as made. There
was Farman’s mile, there was the flight of the Comte de Lambert over
the Eiffel Tower, Latham’s flight at Blackpool in a high wind, the
Rheims records, and then Henry Farman’s flight of four hours later in
1909, Orville Wright’s height record of 1,640 feet, and Delagrange’s
speed record of 49·9 miles per hour. The coming to fame of the Gnome
rotary engine helped in the making of these records to a very great
extent, for in this engine was a prime mover which gave the reliability
that aeroplane builders and pilots had been searching for, but vainly.
The Wrights and Glenn Curtiss, of course, had their own designs of
engine, but the Gnome, in spite of its lack of economy in fuel and oil,
and its high cost, soon came to be regarded as the best power plant for
flight.
Delagrange, one of the very good pilots of the early days, provided a
curious insight to the way in which flying was regarded, at the opening
of the Juvisy aerodrome in May of 1909. A huge crowd had gathered for
the first day’s flying, and nine machines were announced to appear,
but only three were brought out. Delagrange made what was considered
an indifferent little flight, and another pilot, one De Bischoff,
attempted to rise, but could not get his machine off the ground.
Thereupon the crowd of 30,000 people lost their tempers, broke down
the barriers surrounding the flying course, and hissed the officials,
who were quite unable to maintain order. Delagrange, however, saved
the situation by making a circuit of the course at a height of thirty
feet from the ground, which won him rounds of cheering and restored
the crowd to good humour. Possibly the smash achieved by Rougier, the
famous racing motorist, who crashed his Voisin biplane after Delagrange
had made his circuit, completed the enjoyment of the spectators.
Delagrange, flying at Argentan in June of 1909, made a flight of
four kilometres at a height of sixty feet; for those days this was a
noteworthy performance. Contemporary with this was Hubert Latham’s
flight of an hour and seven minutes on an Antoinette monoplane; this
won the adjective ‘magnificent’ from contemporary recorders of aviation.
Viewing the work of the little group of French experimenters, it is,
at this length of time from their exploits, difficult to see why
they carried the art as far as they did. There was in it little of
satisfaction, a certain measure of fame, and practically no profit--the
giants of those days got very little for their pains. Delagrange’s
experience at the opening of the Juvisy ground was symptomatic of the
way in which flight was regarded by the great mass of people--it was a
sport, and nothing more, but a sport without the dividends attaching to
professional football or horse-racing. For a brief period, after the
Rheims meeting, there was a golden harvest to be reaped by the best of
the pilots. Henry Farman asked £2,000 for a week’s exhibition flying
in England, and Paulhan asked half that sum, but a rapid increase
in the number of capable pilots, together with the fact that most
flying meetings were financial failures, owing to great expense in
organisation and the doubtful factor of the weather, killed this goose
before many golden eggs had been gathered in by the star aviators.
Besides, as height and distance records were broken one after another,
it became less and less necessary to pay for entrance to an aerodrome
in order to see a flight--the thing grew too big for a mere sports
ground.
Long before Rheims and the meeting there, aviation had grown too big
for the chronicling of every individual effort. In that period of the
first days of conquest of the air, so much was done by so many whose
names are now half-forgotten that it is possible only to pick out
the great figures and make brief reference to their achievements and
the machines with which they accomplished so much, pausing to note
such epoch-making events as the London-Manchester flight, Bleriot’s
Channel crossing, and the Rheims meeting itself, and then passing on
beyond the days of individual records to the time when the machine
began to dominate the man. This latter because, in the early days,
it was heroism to trust life to the planes that were turned out--the
‘Demoiselle’ and the Antoinette machine that Latham used in his attempt
to fly the Channel are good examples of the flimsiness of early
types--while in the later period, that of the war and subsequently,
the heroism turned itself in a different--and nobler--direction.
Design became standardised, though not perfected. The domination of
the machine may best be expressed by contrasting the way in which
machines came to be regarded as compared with the men who flew them: up
to 1909, flying enthusiasts talked of Farman, of Bleriot, of Paulhan,
Curtiss, and of other men; later, they began to talk of the Voisin, the
Deperdussin, and even to the Fokker, the Avro, and the Bristol type.
With the standardising of the machine, the days of the giants came to
an end.
XIII
FIRST FLIERS IN ENGLAND
Certain experiments made in England by Mr Phillips seem to have come
near robbing the Wright Brothers of the honour of the first flight;
notes made by Colonel J. D. Fullerton on the Phillips flying machine
show that in 1893 the first machine was built with a length of 25 feet,
breadth of 22 feet, and height of 11 feet, the total weight, including
a 72 lb. load, being 420 lbs. The machine was fitted with some fifty
wood slats, in place of the single supporting surface of the monoplane
or two superposed surfaces of the biplane, these slats being fixed in
a steel frame so that the whole machine rather resembled a Venetian
blind. A steam engine giving about 9 horse-power provided the motive
power for the six-foot diameter propeller which drove the machine. As
it was not possible to put a passenger in control as pilot, the machine
was attached to a central post by wire guys and run round a circle 100
feet in diameter, the track consisting of wooden planking 4 feet wide.
Pressure of air under the slats caused the machine to rise some two or
three feet above the track when sufficient velocity had been attained,
and the best trials were made on June 19th, 1893, when at a speed of 40
miles an hour, with a total load of 385 lbs., all the wheels were off
the ground for a distance of 2,000 feet.
In 1904 a full-sized machine was constructed by Mr Phillips, with a
total weight, including that of the pilot, of 600 lbs. The machine
was designed to lift when it had attained a velocity of 50 feet per
second, the motor fitted giving 22 horse-power. On trial, however,
the longitudinal equilibrium was found to be defective, and a further
design was got out, the third machine being completed in 1907. In this
the wood slats were held in four parallel container frames, the weight
of the machine, excluding the pilot, being 500 lbs. A motor similar to
that used in the 1904 machine was fitted, and the machine was designed
to lift at a velocity of about 30 miles an hour, a seven-foot propeller
doing the driving. Mr Phillips tried out this machine in a field about
400 yards across. ‘The machine was started close to the hedge, and rose
from the ground when about 200 yards had been covered. When the machine
touched the ground again, about which there could be no doubt, owing to
the terrific jolting, it did not run many yards. When it came to rest I
was about ten yards from the boundary. Of course, I stopped the engine
before I commenced to descend.’[6]
S. F. Cody, an American by birth, aroused the attention not only of
the British public, but of the War Office and Admiralty as well, as
early as 1905 with his man-lifting kites. In that year a height of
1,600 feet was reached by one of these box-kites, carrying a man, and
later in the same year one Sapper Moreton, of the Balloon Section of
the Royal Engineers (the parent of the Royal Flying Corps) remained
for an hour at an altitude of 2,600 feet. Following on the success
of these kites, Cody constructed an aeroplane which he designated a
‘power kite,’ which was in reality a biplane that made the first flight
in Great Britain. Speaking before the Aeronautical Society in 1908,
Cody said that ‘I have accomplished one thing that I hoped for very
much, that is, to be the first man to fly in Great Britain.... I made
a machine that left the ground the first time out; not high, possibly
five or six inches only. I might have gone higher if I wished. I made
some five flights in all, and the last flight came to grief.... On
the morning of the accident I went out after adjusting my propellers
at 8 feet pitch running at 600 (revolutions per minute). I think that
I flew at about twenty-eight miles per hour. I had 50 horse-power
motor power in the engine. A bunch of trees, a flat common above these
trees, and from this flat there is a slope goes down ... to another
clump of trees. Now, these clumps of trees are a quarter of a mile
apart or thereabouts.... I was accused of doing nothing but jumping
with my machine, so I got a bit agitated and went to fly. I went out
this morning with an easterly wind, and left the ground at the bottom
of the hill and struck the ground at the top, a distance of 74 yards.
That proved beyond a doubt that the machine would fly--it flew uphill.
That was the most talented flight the machine did, in my opinion.
Now, I turned round at the top and started the machine and left the
ground--remember, a ten mile wind was blowing at the time. Then, 60
yards from where the men let go, the machine went off in this direction
(demonstrating)--I make a line now where I hoped to land--to cut these
trees off at that side and land right off in here. I got here somewhat
excited, and started down and saw these trees right in front of me. I
did not want to smash my head rudder to pieces, so I raised it again
and went up. I got one wing direct over that clump of trees, the right
wing over the trees, the left wing free; the wind, blowing with me, had
to lift over these trees. So I consequently got a false lift on the
right side and no lift on the left side. Being only about 8 feet from
the tree tops, that turned my machine up like that (demonstrating).
This end struck the ground shortly after I had passed the trees. I
pulled the steering handle over as far as I could. Then I faced another
bunch of trees right in front of me. Trying to avoid this second bunch
of trees I turned the rudder, and turned it rather sharp. That side
of the machine struck, and it crumpled up like so much tissue paper,
and the machine spun round and struck the ground that way on, and the
framework was considerably wrecked. Now, I want to advise all aviators
not to try to fly with the wind and to cross over any big clump of
earth or any obstacle of any description unless they go square over the
top of it, because the lift is enormous crossing over anything like
that, and in coming the other way against the wind it would be the same
thing when you arrive at the windward side of the obstacle. That is a
point I did not think of, and had I thought of it I would have been
more cautious.’
[Illustration: Colonel Cody’s man-lifting kite, in mid-air, with an
officer of the Royal Engineers in basket.]
[Illustration: Rheims Meeting: Lieutenant Bassel _en cerf volant_.]
This Cody machine was a biplane with about 40 foot span, the wings
being about 7 feet in depth with about 8 feet between upper and lower
wing surfaces. ‘Attached to the extremities of the lower planes are
two small horizontal planes or rudders, while a third small vertical
plane is fixed over the centre of the upper plane.’ The tail-piece and
principal rudder were fitted behind the main body of the machine, and
a horizontal rudder plane was rigged out in front, on two supporting
arms extending from the centre of the machine. The small end-planes
and the vertical plane were used in conjunction with the main rudder
when turning to right or left, the inner plane being depressed on the
turn, and the outer one correspondingly raised, while the vertical
plane, working in conjunction, assisted in preserving stability. Two
two-bladed propellers were driven by an eight-cylinder 50 horse-power
Antoinette motor. With this machine Cody made his first flights over
Laffan’s plain, being then definitely attached to the Balloon Section
of the Royal Engineers as military aviation specialist.
There were many months of experiment and trial, after the accident
which Cody detailed in the statement given above, and then, on May
14th, 1909, Cody took the air and made a flight of 1,200 yards with
entire success. Meanwhile A. V. Roe was experimenting at Lea Marshes
with a triplane of rather curious design, the pilot having his seat
between two sets of three superposed planes, of which the front planes
could be tilted and twisted while the machine was in motion. He
comes but a little way after Cody in the chronology of early British
experimenters, but Cody, a born inventor, must be regarded as the
pioneer of the present century so far as Britain is concerned. He
was neither engineer nor trained mathematician, but he was a good
rule-of-thumb mechanic and a man of pluck and perseverance; he never
strove to fly on an imperfect machine, but made alteration after
alteration in order to find out what was improvement and what was
not, in consequence of which it was said of him that he was ‘always
satisfied with his alterations.’
By July of 1909 he had fitted an 80 horse-power motor to his biplane,
and with this he made a flight of over four miles over Laffan’s Plain
on July 21st. By August he was carrying passengers, the first being
Colonel Capper of the R.E. Balloon Section, who flew with Cody for
over two miles, and on September 8th, 1909, he made a world’s record
cross-country flight of over forty miles in sixty-six minutes, taking
a course from Laffan’s Plain over Farnborough, Rushmoor, and Fleet,
and back to Laffan’s Plain. He was one of the competitors in the 1909
Doncaster Aviation Meeting, and in 1910 he competed at Wolverhampton,
Bournemouth, and Lanark. It was on June 7th, 1910, that he qualified
for his brevet, No. 9, on the Cody biplane.
He built a machine which embodied all the improvements for which he
had gained experience, in 1911, a biplane with a length of 35 feet
and span of 43 feet, known as the ‘Cody cathedral’ on account of its
rather cumbrous appearance. With this, in 1911, he won the two Michelin
trophies presented in England, completed the _Daily Mail_ circuit of
Britain, won the Michelin cross-country prize in 1912, and altogether,
by the end of 1912, had covered more than 7,000 miles with the machine.
It was fitted with a 120 horse-power Austro-Daimler engine, and was
characterised by an exceptionally wide range of speed--the great
wing-spread gave a slow landing speed.
A few of his records may be given: in 1910, flying at Laffan’s Plain in
his biplane, fitted with a 50–60 horse-power Green engine, on December
31st, he broke the records for distance and time by flying 185 miles,
787 yards, in 4 hours 37 minutes. On October 31st, 1911, he beat this
record by flying for 5 hours 15 minutes, in which period he covered
261 miles 810 yards with a 60 horse-power Green engine fitted to his
biplane. In 1912, competing in the British War Office tests of military
aeroplanes, he won the £5,000 offered by the War Office. This was in
competition with no less than twenty-five other machines, among which
were the since-famous Deperdussin, Bristol, Flanders, and Avro types,
as well as the Maurice Farman and Bleriot makes of machine. Cody’s
remarkable speed range was demonstrated in these trials, the speeds of
his machine varying between 72.4 and 48.5 miles per hour. The machine
was the only one delivered for the trials by air, and during the three
hours’ test imposed on all competitors a maximum height of 5,000 feet
was reached, the first thousand feet being achieved in three and a half
minutes.
During the summer of 1913, Cody put his energies into the production
of a large hydro-biplane, with which he intended to win the £5,000
prize offered by the _Daily Mail_ to the first aviator to fly round
Britain on a waterplane. This machine was fitted with landing gear for
its tests, and, while flying it over Laffan’s Plain on August 7th,
1913, with Mr W. H. B. Evans as passenger, Cody met with the accident
that cost both him and his passenger their lives. Aviation lost a
great figure by his death, for his plodding, experimenting, and dogged
courage not only won him the fame that came to a few of the pilots of
those days, but also advanced the cause of flying very considerably and
contributed not a little to the sum of knowledge in regard to design
and construction.
Another figure of the early days was A. V. Roe, who came from marine
engineering to the motor industry and aviation in 1905. In 1906 he
went out to Colorado, getting out drawings for the Davidson helicopter,
and in 1907, having returned to England, he obtained highest award out
of 200 entries in a model aeroplane flying competition. From the design
of this model he built a full-sized machine, and made a first flight on
it, fitted with a 24 horse-power Antoinette engine, in June of 1908.
Later, he fitted a 9 horse-power motor-cycle engine to a triplane
of his own design, and with this made a number of short flights; he
got his flying brevet on a triplane with a motor of 35 horse-power,
which, together with a second triplane, was entered for the Blackpool
aviation meeting of 1910, but was burnt in transport to the meeting.
He was responsible for the building of the first seaplane to rise from
English waters, and may be counted the pioneer of the tractor type
of biplane. In 1913 he built a two-seater tractor biplane with 80
horse-power engine, a machine which for some considerable time ranked
as a leader of design. Together with E. V. Roe and H. V. Roe, ‘A. V.’
controlled the Avro works, which produced some of the most famous
training machines of the war period in a modification of the original
80 horse-power tractor. The first of the series of Avro tractors
to be adopted by the military authorities was the 1912 biplane, a
two-seater fitted with 50 horse-power engine. It was the first tractor
biplane with a closed fuselage to be used for military work, and
became standard for the type. The Avro seaplane, of 100 horse-power (a
fourteen-cylinder Gnome engine was used) was taken up by the British
Admiralty in 1913. It had a length of 34 feet and a wing-span of 50
feet, and was of the twin-float type.
Geoffrey de Havilland, though of later rank, counts high among
designers of British machines. He qualified for his brevet as late
as February, 1911, on a biplane of his own construction, and became
responsible for the design of the BE2, the first successful British
Government biplane. On this he made a British height record of 10,500
feet over Salisbury Plain, in August of 1912, when he took up Major
Sykes as passenger. In the war period he was one of the principal
designers of fighting and reconnaissance machines.
F. Handley Page, who started in business as an aeroplane builder in
1908, having works at Barking, was one of the principal exponents of
the inherently stable machine, to which he devoted practically all
his experimental work up to the outbreak of war. The experiments were
made with various machines, both of monoplane and biplane type, and of
these one of the best was a two-seater monoplane built in 1911, while a
second was a larger machine, a biplane, built in 1913 and fitted with
a no horse-power Anzani engine. The war period brought out the giant
biplane with which the name of Handley Page is most associated, the
twin-engined night-bomber being a familiar feature of the later days
of the war; the four-engined bomber had hardly had a chance of proving
itself under service conditions when the war came to an end.
Another notable figure of the early period was ‘Tommy’ Sopwith, who
took his flying brevet at Brooklands in November of 1910, and within
four days made the British duration record of 108 miles in 3 hours 12
minutes. On December 18th, 1910, he won the Baron de Forrest prize of
£4,000 for the longest flight from England to the Continent, flying
from Eastchurch to Tirlemont, Belgium, in three hours, a distance
of 161 miles. After two years of touring in America, he returned to
England and established a flying school. In 1912 he won the first
aerial Derby, and in 1913 a machine of his design, a tractor biplane,
raised the British height record to 13,000 feet (June 16th, at
Brooklands). First as aviator, and then as designer, Sopwith has done
much useful work in aviation.
These are but a few, out of a host who contributed to the development
of flying in this country, for, although France may be said to have
set the pace as regards development, Britain was not far behind.
French experimenters received far more Government aid than did the
early British aviators and designers--in the early days the two were
practically synonymous, and there are many stories of the very early
days at Brooklands, where, when funds ran low, the ardent spirits
patched their trousers with aeroplane fabric and went on with their
work with Bohemian cheeriness. Cody, altering and experimenting
on Laffan’s Plain, is the greatest figure of them all, but others
rank, too, as giants of the early days, before the war brought full
recognition of the aeroplane’s potentialities.
One of the first men actually to fly in England, Mr J. C. T.
Moore-Brabazon, was a famous figure in the days of exhibition flying,
and won his reputation mainly through being first to fly a circular
mile on a machine designed and built in Great Britain and piloted by
a British subject. Moore-Brabazon’s earliest flights were made in
France on a Voisin biplane in 1908, and he brought this machine over to
England, to the Aero Club grounds at Shellness, but soon decided that
he would pilot a British machine instead. An order was placed for a
Short machine, and this, fitted with a 50–60 horse-power Green engine,
was used for the circular mile, which won a prize of £1,000 offered by
the _Daily Mail_, the feat being accomplished on October 30th, 1909.
Five days later, Moore Brabazon achieved the longest flight up to that
time accomplished on a British-built machine, covering three and a half
miles. In connection with early flying in England, it is claimed that
A. V. Roe, flying ‘Avro B,’ on June 8th, 1908, was actually the first
man to leave the ground, this being at Brooklands, but in point of fact
Cody antedated him.
No record of early British fliers could be made without the name of
C. S. Rolls, a son of Lord Llangattock. On June 2nd, 1910, he flew
across the English Channel to France, until he was duly observed over
French territory, when he returned to England without alighting. The
trip was made on a Wright biplane, and was the third Channel crossing
by air, Bleriot having made the first, and Jacques de Lesseps the
second. Rolls was first to make the return journey in one trip. He
was eventually killed through the breaking of the tail-plane of his
machine in descending at a flying meeting at Bournemouth. The machine
was a Wright biplane, but the design of the tail-plane--which, by the
way, was an addition to the machine, and was not even sanctioned by
the Wrights--appears to have been carelessly executed, and the plane
itself was faulty in construction. The breakage caused the machine to
overturn, killing Rolls, who was piloting it.
XIV
RHEIMS, AND AFTER
The foregoing brief--and necessarily incomplete--survey of the early
British group of fliers has taken us far beyond some of the great
events of the early days of successful flight, and it is necessary
to go back to certain landmarks in the history of aviation, first
of which is the great meeting at Rheims in 1909. Wilbur Wright had
come to Europe, and, flying at Le Mans and Pau--it was on August 8th,
1908, that Wilbur Wright made the first of his ascents in Europe--had
stimulated public interest in flying in France to a very great
degree. Meanwhile, Orville Wright, flying at Fort Meyer, U.S.A., with
Lieutenant Selfridge as a passenger, sustained an accident which
very nearly cost him his life through the transmission gear of the
motor breaking. Selfridge was killed and Orville Wright was severely
injured--it was the first fatal accident with a Wright machine.
Orville Wright made a flight of over an hour on September 9th, 1908,
and on December 31st of that year Wilbur flew for 2 hours 19 minutes.
Thus, when the Rheims meeting was organised--more notable because
it was the first of its kind, there were already records waiting to
be broken. The great week opened on August 22nd, there being thirty
entrants, including all the most famous men among the early fliers in
France. Bleriot, fresh from his Channel conquest, was there, together
with Henry Farman, Paulhan, Curtiss, Latham, and the Comte de Lambert,
first pupil of the Wright machine in Europe to achieve a reputation as
an aviator.
‘To say that this week marks an epoch in the history of the world is
to state a platitude. Nevertheless, it is worth stating, and for us
who are lucky enough to be at Rheims during this week there is a solid
satisfaction in the idea that we are present at the making of history.
In perhaps only a few years to come the competitions of this week may
look pathetically small and the distances and speeds may appear paltry.
Nevertheless, they are the first of their kind, and that is sufficient.’
So wrote a newspaper correspondent who was present at the famous
meeting, and his words may stand, being more than mere journalism; for
the great flying week which opened on August 22nd, 1909, ranks as one
of the great landmarks in the history of heavier-than-air flight. The
day before the opening of the meeting a downpour of rain spoilt the
flying ground; Sunday opened with a fairly high wind, and in a lull M.
Guffroy turned out on a crimson R.E.P. monoplane, but the wheels of
his undercarriage stuck in the mud and prevented him from rising in
the quarter of an hour allowed to competitors to get off the ground.
Bleriot, following, succeeded in covering one side of the triangular
course, but then came down through grit in the carburettor. Latham,
following him with thirteen as the number of his machine, experienced
his usual bad luck and came to earth through engine trouble after a
very short flight. Captain Ferber, who, owing to military regulations,
always flew under the name of De Rue, came out next with his Voisin
biplane, but failed to get off the ground; he was followed by Lefebvre
on a Wright biplane, who achieved the success of the morning by
rounding the course--a distance of six and a quarter miles--in nine
minutes with a twenty mile an hour wind blowing. His flight finished
the morning.
Wind and rain kept competitors out of the air until the evening, when
Latham went up, to be followed almost immediately by the Comte de
Lambert. Sommer, Cockburn (the only English competitor), Delagrange,
Fournier, Lefebvre, Bleriot, Bunau-Varilla, Tissandier, Paulhan, and
Ferber turned out after the first two, and the excitement of the
spectators at seeing so many machines in the air at one time provoked
wild cheering. The only accident of the day came when Bleriot damaged
his propeller in colliding with a haycock.
The main results of the day were that the Comte de Lambert flew 30
kilometres in 29 minutes 2 seconds; Lefebvre made the ten-kilometre
circle of the track in just a second under 9 minutes, while Tissandier
did it in 9¼ minutes, and Paulhan reached a height of 230 feet. Small
as these results seem to us now, and ridiculous as may seem enthusiasm
at the sight of a few machines in the air at the same time, the Rheims
Meeting remains a great event, since it proved definitely to the whole
world that the conquest of the air had been achieved.
Throughout the week record after record was made and broken. Thus
on the Monday, Lefebvre put up a record for rounding the course
and Bleriot beat it, to be beaten in turn by Glenn Curtiss on his
Curtiss-Herring biplane. On that day, too, Paulhan covered 34¾ miles
in 1 hour 6 minutes. On the next day, Paulhan on his Voisin biplane
took the air with Latham, and Fournier followed, only to smash up his
machine by striking an eddy of wind which turned him over several
times. On the Thursday, one of the chief events was Latham’s 43 miles
accomplished in 1 hour 2 minutes in the morning and his 96.5 miles in
2 hours 13 minutes in the afternoon, the latter flight only terminated
by running out of petrol. On the Friday, the Colonel Renard French
airship, which had flown over the ground under the pilotage of M.
Kapfarer, paid Rheims a second visit; Latham manœuvred round the
airship on his Antoinette and finally left it far behind. Henry Farman
won the Grand Prix de Champagne on this day, covering 112 miles in 3
hours, 4 minutes, 56 seconds, Latham being second with his 96.5 miles
flight, and Paulhan third.
On the Saturday, Glenn Curtiss came to his own, winning the
Gordon-Bennett Cup by covering 20 kilometres in 15 minutes 50.6
seconds. Bleriot made a good second with 15 minutes 56.2 seconds as his
time, and Latham and Lefebvre were third and fourth. Farman carried off
the passenger prize by carrying two passengers a distance of 6 miles
in 10 minutes 39 seconds. On the last day Delagrange narrowly escaped
serious accident through the bursting of his propeller while in the
air, Curtiss made a new speed record by travelling at the rate of over
50 miles an hour, and Latham, rising to 500 feet, won the altitude
prize.
[Illustration: M. Tissandier’s ‘Wright’ machine (showing starting
method).]
These are the cold statistics of the meeting; at this length of time
it is difficult to convey any idea of the enthusiasm of the crowds
over the achievements of the various competitors, while the incidents
of the week, comic and otherwise, are nearly forgotten now even by
those present in this making of history. Latham’s great flight on
the Thursday was rendered a breathless episode by a downpour of
rain when he had covered all but a kilometre of the record distance
previously achieved by Paulhan, and there was wild enthusiasm when
Latham flew on through the rain until he had put up a new record and
his petrol had run out. Again, on the Friday afternoon, the Colonel
Renard took the air together with a little French dirigible, Zodiac
III; Latham was already in the air directly over Farman, who was
also flying, and three crows which turned out as rivals to the human
aviators received as much cheering for their appearance as had been
accorded to the machines, which doubtless they could not understand.
Frightened by the cheering, the crows tried to escape from the course,
but as they came near the stands, the crowd rose to cheer again and
the crows wheeled away to make a second charge towards safety, with
the same result; the crowd rose and cheered at them a third and fourth
time; between ten and fifteen thousand people stood on chairs and
tables and waved hats and handkerchiefs at three ordinary, everyday
crows. One thoughtful spectator, having thoroughly enjoyed the funny
side of the incident, remarked that the ultimate mastery of the air
lies with the machine that comes nearest to natural flight. This still
remains for the future to settle.
Farman’s world record, which won the Grand Prix de Champagne, was done
with a Gnome Rotary Motor which had only been run on the test bench and
was fitted to his machine four hours before he started on the great
flight. His propeller had never been tested, having only been completed
the night before. The closing laps of that flight, extending as they
did into the growing of the dusk, made a breathlessly eerie experience
for such of the spectators as stayed on to watch--and these were
many. Night came on steadily and Farman covered lap after lap just as
steadily, a buzzing, circling mechanism with something relentless in
its isolated persistency.
The final day of the meeting provided a further record in the quarter
million spectators who turned up to witness the close of the great
week. Bleriot, turning out in the morning, made a landing in some
such fashion as flooded the carburettor and caused it to catch fire.
Bleriot himself was badly burned, since the petrol tank burst and, in
the end, only the metal parts of the machine were left. Glenn Curtis
tried to beat Bleriot’s time for a lap of the course, but failed. In
the evening, Farman and Latham went out and up in great circles, Farman
cleaving his way upward in what at the time counted for a huge machine,
on circles of about a mile diameter. His first round took him level
with the top of the stands, and, in his second, he circled the captive
balloon anchored in the middle of the grounds. After another circle, he
came down on a long glide, when Latham’s lean Antoinette monoplane went
up in circles more graceful than those of Farman. ‘Swiftly it rose and
swept round close to the balloon, veered round to the hangars, and out
over to the Rheims road. Back it came high over the stands, the people
craning their necks as the shrill cry of the engine drew nearer and
nearer behind the stands. Then of a sudden, the little form appeared
away up in the deep twilight blue vault of the sky, heading straight
as an arrow for the anchored balloon. Over it, and high, high above
it went the Antoinette, seemingly higher by many feet than the Farman
machine. Then, wheeling in a long sweep to the left, Latham steered his
machine round past the stands, where the people, their nerve-tension
released on seeing the machine descending from its perilous height
of 500 feet, shouted their frenzied acclamations to the hero of the
meeting.
[Illustration: Rheims Aviation Week. M. Lefebvre’s ‘Wright’ machine in
flight.]
‘For certainly “Le Tham,” as the French call him, was the popular hero.
He always flew high, he always flew well, and his machine was a joy to
the eye, either afar off or at close quarters. The public feeling for
Bleriot is different. Bleriot, in the popular estimation, is the man
who fights against odds, who meets the adverse fates calmly and with
good courage, and to whom good luck comes once in a while as a reward
for much labour and anguish, bodily and mental. Latham is the darling
of the Gods, to whom Fate has only been unkind in the matter of the
Channel flight, and only then because the honour belonged to Bleriot.
‘Next to these two, the public loved most Lefebvre, the joyous, the
gymnastic. Lefebvre was the comedian of the meeting. When things began
to flag, the gay little Lefebvre would trot out to his starting rail,
out at the back of the judge’s enclosure opposite the stands, and after
a little twisting of propellers his Wright machine would bounce off the
end of its starting rail and proceed to do the most marvellous tricks
for the benefit of the crowd, wheeling to right and left, darting up
and down, now flying over a troop of the cavalry who kept the plain
clear of people and sending their horses into hysterics, anon making
straight for an unfortunate photographer who would throw himself and
his precious camera flat on the ground to escape annihilation as
Lefebvre swept over him 6 or 7 feet off the ground. Lefebvre was great
fun, and when he had once found that his machine was not fast enough
to compete for speed with the Bleriots, Antoinettes, and Curtiss, he
kept to his _métier_ of amusing people. The promoters of the meeting
owe Lefebvre a debt of gratitude, for he provided just the necessary
comic relief.’--(_The Aero_, September 7th, 1909.)
It may be noted, in connection with the fact that Cockburn was the
only English competitor at the meeting, that the Rheims Meeting did
more than anything which had preceded it to waken British interest
in aviation. Previously, heavier-than-air flight in England had been
regarded as a freak business by the great majority, and the very few
pioneers who persevered toward winning England a share in the conquest
of the air came in for as much derision as acclamation. Rheims altered
this; it taught the world in general, and England in particular, that
a serious rival to the dirigible balloon had come to being, and it
awakened the thinking portion of the British public to the fact that
the aeroplane had a future.
[Illustration: Doncaster flying week. Cody Flying.]
The success of this great meeting brought about a host of imitations
of which only a few deserve bare mention since, unlike the first, they
taught nothing and achieved little. There was the meeting at Boulogne
late in September of 1909, of which the only noteworthy event was
Ferber’s death. There was a meeting at Brescia where Curtiss again took
first prize for speed and Rougier put up a world’s height record of 645
feet. The Blackpool meeting followed between 18th and 23rd of October,
1909, forming, with the exception of Doncaster, the first British
Flying Meeting. Chief among the competitors were Henry Farman, who took
the distance prize, Rougier, Paulhan, and Latham, who, by a flight in a
high wind, convinced the British public that the theory that flying
was only possible in a calm was a fallacy. A meeting at Doncaster was
practically simultaneous with the Blackpool week; Delagrange, Le Blon,
Sommer, and Cody were the principal figures in this event. It should
be added that 130 miles was recorded as the total flown at Doncaster,
while at Blackpool only 115 miles were flown. Then there were Juvisy,
the first Parisian meeting, Wolverhampton, and the Comte de Lambert’s
flight round the Eiffel Tower at a height estimated at between 1,200
and 1,300 feet. This may be included in the record of these aerial
theatricals, since it was nothing more.
Probably wakened to realisation of the possibilities of the aeroplane
by the Rheims Meeting, Germany turned out its first plane late in 1909.
It was known as the Grade monoplane, and was a blend of the Bleriot
and Santos-Dumont machines, with a tail suggestive of the Antoinette
type. The main frame took the form of a single steel tube, at the
forward end of which was rigged a triangular arrangement carrying the
pilot’s seat and the landing wheels underneath, with the wing warping
wires and stays above. The sweep of the wings was rather similar to the
later Taube design, though the sweep back was not so pronounced, and
the machine was driven by a four-cylinder, 20 horse-power, air-cooled
engine which drove a two-bladed tractor propeller. In spite of
Lilienthal’s pioneer work years before, this was the first power-driven
German plane which actually flew.
Eleven months after the Rheims meeting came what may be reckoned the
only really notable aviation meeting on English soil, in the form of
the Bournemouth week, July 10th to 16th, 1910. This gathering is
noteworthy mainly in view of the amazing advance which it registered
on the Rheims performances. Thus, in the matter of altitude, Morane
reached 4,107 feet and Drexel came second with 2,490 feet. Audemars
on a Demoiselle monoplane made a flight of 17 miles 1,480 yards in 27
minutes 17.2 seconds, a great flight for the little Demoiselle. Morane
achieved a speed of 56.64 miles per hour, and Grahame White climbed
to 1,000 feet altitude in 6 minutes 36.8 seconds. Machines carrying
the Gnome engine as power unit took the great bulk of the prizes, and
British-built engines were far behind.
[Illustration: Rolls executing a turn (note tilt).]
[Illustration: Fatal accident to Rolls. Bournemouth Aviation Week.]
The Bournemouth Meeting will always be remembered with regret for the
tragedy of C. S. Rolls’s death, which took place on the Tuesday, the
second day of the meeting. The first competition of the day was that
for the landing prize; Grahame White, Audemars, and Captain Dickson
had landed with varying luck, and Rolls, following on a Wright machine
with a tail-plane which ought never to have been fitted and was not
part of the Wright design, came down wind after a left-hand turn and
turned left again over the top of the stands in order to land up wind.
He began to dive when just clear of the stands, and had dropped to a
height of 40 feet when he came over the heads of the people against the
barriers. Finding his descent too steep, he pulled back his elevator
lever to bring the nose of the machine up, tipping down the front end
of the tail to present an almost flat surface to the wind. Had all
gone well, the nose of the machine would have been forced up, but the
strain on the tail and its four light supports was too great; the tail
collapsed, the wind pressed down the biplane elevator, and the
machine dived vertically for the remaining 20 feet of the descent,
hitting the ground vertically and crumpling up. Major Kennedy, first
to reach the debris, found Rolls lying with his head doubled under him
on the overturned upper main plane; the lower plane had been flung
some few feet away with the engine and tanks under it. Rolls was
instantaneously killed by concussion of the brain.
Antithesis to the tragedy was Audemars on his Demoiselle, which was
named ‘The Infuriated Grasshopper.’ Concerning this, it was recorded
at the time that ‘Nothing so excruciatingly funny as the action of
this machine has ever been seen at any aviation ground. The little
two-cylinder engine pops away with a sound like the frantic drawing of
ginger beer corks; the machine scutters along the ground with its tail
well up; then down comes the tail suddenly and seems to slap the ground
while the front jumps up, and all the spectators rock with laughter.
The whole attitude and the jerky action of the machine suggest a
grasshopper in a furious rage, and the impression is intensified when
it comes down, as it did twice on Wednesday, in long grass, burying its
head in the ground in its temper.’--(_The Aero_, July, 1910.)
The Lanark Meeting followed in August of the same year, and with the
bare mention of this, the subject of flying meetings may be left alone,
since they became mere matters of show until there came military
competitions such as the Berlin Meeting at the end of August, 1910,
and the British War Office Trials on Salisbury Plain, when Cody won
his greatest triumphs. The Berlin meeting proved that, from the time
of the construction of the first successful German machine mentioned
above, to the date of the meeting, a good number of German aviators
had qualified for flight, but principally on Wright and Antoinette
machines, though by that time the Aviatik and Dorner German makes had
taken the air. The British War Office Trials deserve separate and
longer mention.
In 1910 in spite of official discouragement, Captain Dickson proved the
value of the aeroplane for scouting purposes by observing movements
of troops during the Military Manœuvres on Salisbury Plain. Lieut.
Lancelot Gibbs and Robert Loraine, the actor-aviator, also made flights
over the manœuvre area, locating troops and in a way anticipating the
formation and work of the Royal Flying Corps by a usefulness which
could not be officially recognised.
[Illustration: Audemars on ‘The Infuriated Grasshopper,’ Bournemouth.
July, 1910.]
XV
THE CHANNEL CROSSING
It may be said that Louis Bleriot was responsible for the second great
landmark in the history of successful flight. The day when the brothers
Wright succeeded in accomplishing power-driven flight ranks as the
first of these landmarks. Ader may or may not have left the ground,
but the wreckage of his ‘Avion’ at the end of his experiment places
his doubtful success in a different category from that of the brothers
Wright and leaves them the first definite conquerors, just as Bleriot
ranks as first definite conqueror of the English Channel by air.
In a way, Louis Bleriot ranks before Farman in point of time; his
first flapping-wing model was built as early as 1900, and Voisin flew
a biplane glider of his on the Seine in the very early experimental
days. Bleriot’s first four machines were biplanes, and his fifth, a
monoplane, was wrecked almost immediately after its construction.
Bleriot had studied Langley’s work to a certain extent, and his sixth
construction was a double monoplane based on the Langley principle. A
month after he had wrecked this without damaging himself--for Bleriot
had as many miraculous escapes as any of the other fliers--he brought
out number seven, a fairly average monoplane. It was in December
of 1907 after a series of flights that he wrecked this machine,
and on its successor, in July of 1908, he made a flight of over 8
minutes. Sundry flights, more or less successful, including the first
cross-country flight from Toury to Artenay, kept him busy up to the
beginning of November, 1908, when the wreckage in a fog of the machine
he was flying sent him to the building of ‘number eleven,’ the famous
cross-channel aeroplane.
Number eleven was shown at the French Aero Show in the Grand Palais
and was given its first trials on the 18th January, 1909. It was first
fitted with a R.E.P. motor and had a lifting area of 120 square feet,
which was later increased to 150 square feet. The framework was of oak
and poplar spliced and reinforced with piano wire; the weight of the
machine was 47 lbs. and the undercarriage weight a further 60 lbs.,
this consisting of rubber cord shock absorbers mounted on two wheels.
The R.E.P. motor was found unsatisfactory, and a three-cylinder Anzani
of 105 mm. bore and 120 mm. stroke replaced it. An accident seriously
damaged the machine on June 2nd, but Bleriot repaired it and tested it
at Issy, where between June 19th and June 23rd he accomplished flights
of 8, 12, 15, 16, and 36 minutes. On July 4th he made a 50-minute
flight and on the 13th flew from Etampes to Chevilly.
[Illustration: Blériot crossing the Channel.]
A few further details of construction may be given: the wings
themselves and an elevator at the tail controlled the rate of ascent
and descent, while a rudder was also fitted at the tail. The steering
lever, working on a universally jointed shaft--forerunner of the modern
joy-stick--controlled both the rudder and the wings, while a pedal
actuated the elevator. The engine drove a two-bladed tractor screw of
6 feet 7 inches diameter, and the angle of incidence of the wings was
20 degrees. Timed at Issy, the speed of the machine was given as 36
miles an hour, and as Bleriot accomplished the Channel flight of 20
miles in 37 minutes, he probably had a slight following wind.
The _Daily Mail_ had offered a prize of £1,000 for the first
Cross-Channel flight, and Hubert Latham set his mind on winning it.
He put up a shelter on the French coast at Sangatte, half-way between
Calais and Cape Blanc Nez. From here he made his first attempt to fly
to England on Monday the 19th of July. He soared to a fair height,
circling, and reached an estimated height of about 900 feet as he came
over the water with every appearance of capturing the Cross-Channel
prize. The luck which dogged his career throughout was against him,
for, after he had covered some 8 miles, his engine stopped and he
came down to the water in a series of long glides. It was discovered
afterward that a small piece of wire had worked its way into a vital
part of the engine to rob Latham of the honour he coveted. The tug that
came to his rescue found him seated on the fuselage of his Antoinette,
smoking a cigarette and waiting for a boat to take him to the tug. It
may be remarked that Latham merely assumed his Antoinette would float
in case he failed to make the English coast; he had no actual proof.
Bleriot immediately entered his machine for the prize and took up his
quarters at Barraques. On Sunday, July 25th, 1909, shortly after 4
a.m., Bleriot had his machine taken out from its shelter and prepared
for flight. He had been recently injured in a petrol explosion and
hobbled out on crutches to make his cross-Channel attempt; he made two
great circles in the air to try the machine, and then alighted. ‘In
ten minutes I start for England,’ he declared, and at 4.35 the motor
was started up. After a run of 100 yards, the machine rose in the air
and got a height of about 100 feet over the land, then wheeling sharply
seaward and heading for Dover.
Bleriot had no means of telling direction, and any change of wind might
have driven him out over the North Sea, to be lost, as were Cecil Grace
and Hamel later on. Luck was with him, however, and at 5.12 a.m. of
that July Sunday, he made his landing in the North Fall meadow, just
behind Dover Castle. Twenty minutes out from the French coast, he lost
sight of the destroyer which was patrolling the Channel, and at the
same time he was out of sight of land without compass or any other
means of ascertaining his direction. Sighting the English coast, he
found that he had gone too far to the east, for the wind increased in
strength throughout the flight, this to such an extent as almost to
turn the machine round when he came over English soil. Profiting by
Latham’s experience, Bleriot had fitted an inflated rubber cylinder a
foot in diameter by 5 feet in length along the middle of his fuselage,
to render floating a certainty in case he had to alight on the water.
[Illustration: Latham starts from Sangatte.]
Latham in his camp at Sangatte had been allowed to sleep through the
calm of the early morning through a mistake on the part of a friend,
and when his machine was turned out in order that he might emulate
Bleriot, although he no longer hoped to make the first flight, it took
so long to get the machine ready and dragged up to its starting-point
that there was a 25 mile an hour wind by the time everything was in
readiness. Latham was anxious to make the start in spite of the wind,
but the Directors of the Antoinette Company refused permission. It
was not until two days later that the weather again became favourable,
and then with a fresh machine, since the one on which he made his first
attempt had been very badly damaged in being towed ashore, he made a
circular trial flight of about 5 miles. In landing from this, a side
gust of wind drove the nose of the machine against a small hillock,
damaging both propeller blades and chassis, and it was not until
evening that the damage was repaired.
French torpedo boats were set to mark the route, and Latham set out on
his second attempt at six o’clock. Flying at a height of 200 feet, he
headed over the torpedo boats for Dover and seemed certain of making
the English coast, but a mile and a half out from Dover his engine
failed him again, and he dropped to the water to be picked up by the
steam pinnace of an English warship and put aboard the French destroyer
_Escopette_.
There is little to choose between the two aviators for courage in
attempting what would have, been considered a foolhardy feat a year or
two before. Bleriot’s state, with an abscess in the burnt foot which
had to control the elevator of his machine, renders his success all the
more remarkable. His machine was exhibited in London for a time, and
was afterwards placed in the Conservatoire des Arts et Métiers, while a
memorial in stone, copying his monoplane in form, was let into the turf
at the point where he landed.
The second Channel crossing was not made until 1910, a year of new
records. The altitude record had been lifted to over 10,000 feet, the
duration record to 8 hours 12 minutes, and the distance for a single
flight to 365 miles, while a speed of over 65 miles an hour had been
achieved, when Jacques de Lesseps, son of the famous engineer of Suez
Canal and Panama fame, crossed from France to England on a Bleriot
monoplane. By this time flying had dropped so far from the marvellous
that this second conquest of the Channel aroused but slight public
interest in comparison with Bleriot’s feat.
The total weight of Bleriot’s machine in Cross Channel trim was 660
lbs., including the pilot and sufficient petrol for a three hours’
run; at a speed of 37 miles an hour, it was capable of carrying about
5 lbs. per square foot of lifting surface. It was the three-cylinder
25 horse-power Anzani motor which drove the machine for the flight.
Shortly after the flight had been accomplished, it was announced that
the Bleriot firm would construct similar machines for sale at £400
apiece--a good commentary on the prices of those days.
On June the 2nd, 1910, the third Channel crossing was made by C. S.
Rolls, who flew from Dover, got himself officially observed over French
soil at Barraques, and then flew back without landing. He was the first
to cross from the British side of the Channel and also was the first
aviator who made the double journey. By that time, however, distance
flights had so far increased as to reduce the value of the feat, and
thenceforth the Channel crossing was no exceptional matter. The honour,
second only to that of the Wright Brothers, remains with Bleriot.
XVI
LONDON TO MANCHESTER
The last of the great contests to arouse public enthusiasm was the
London to Manchester Flight of 1910. As far back as 1906, the _Daily
Mail_ had offered a prize of £10,000 to the first aviator who should
accomplish this journey, and, for a long time, the offer was regarded
as a perfectly safe one for any person or paper to make--it brought
forth far more ridicule than belief. _Punch_ offered a similar sum
to the first man who should swim the Atlantic and also for the first
flight to Mars and back within a week, but in the spring of 1910 Claude
Grahame White and Paulhan, the famous French pilot, entered for the
183 mile run on which the prize depended. Both these competitors flew
the Farman biplane with the 50 horse-power Gnome motor as propulsive
power. Grahame White surveyed the ground along the route, and the L.
& N. W. Railway Company, at his request, whitewashed the sleepers for
100 yards on the north side of all junctions to give him his direction
on the course. The machine was run out on to the starting ground at
Park Royal and set going at 5.19 a.m. on April 23rd. After a run of
100 yards, the machine went up over Wormwood Scrubs on its journey to
Normandy, near Hillmorten, which was the first arranged stopping place
_en route_; Grahame White landed here in good trim at 7.20 a.m., having
covered 75 miles and made a world’s record cross country flight. At
8.15 he set off again to come down at Whittington, four miles short of
Lichfield, at about 9.20, with his machine in good order except for a
cracked landing skid. Twice, on this second stage of the journey, he
had been caught by gusts of wind which turned the machine fully round
toward London, and, when over a wood near Tamworth, the engine stopped
through a defect in the balance springs of two exhaust valves; although
it started up again after a 100 foot glide, it did not give enough
power to give him safety in the gale he was facing. The rising wind
kept him on the ground throughout the day, and, though he hoped for
better weather, the gale kept up until the Sunday evening. The men in
charge of the machine during its halt had attempted to hold the machine
down instead of anchoring it with stakes and ropes, and, in consequence
of this, the wind blew the machine over on its back, breaking the upper
planes and the tail. Grahame White had to return to London, while the
damaged machine was prepared for a second flight. The conditions of the
competition enacted that the full journey should be completed within 24
hours, which made return to the starting ground inevitable.
Louis Paulhan, who had just arrived with his Farman machine,
immediately got it unpacked and put together in order to be ready to
make his attempt for the prize as soon as the weather conditions should
admit. At 5.31 p.m., on April 27th, he went up from Hendon and had
travelled 50 miles when Grahame White, informed of his rival’s start,
set out to overtake him. Before nightfall Paulhan landed at Lichfield,
117 miles from London, while Grahame White had to come down at Roden,
only 60 miles out. The English aviator’s chance was not so small as it
seemed, for, as Latham had found in his cross-Channel attempts, engine
failure was more the rule than the exception, and a very little thing
might reverse the relative positions.
A special train accompanied Paulhan along the North-Western route,
conveying Madame Paulhan, Henry Farman, and the mechanics who fitted
the Farman biplane together. Paulhan himself, who had flown at a height
of 1,000 feet, spent the night at Lichfield, starting again at 4.9 a.m.
on the 28th, passing Stafford at 4.45, Crewe at 5.20, and landing at
Burnage, near Didsbury, at 5.32, having had a clean run.
Meanwhile, Grahame White had made a most heroic attempt to beat his
rival. An hour before dawn on the 28th, he went to the small field in
which his machine had landed, and in the darkness managed to make an
ascent from ground which made starting difficult even in daylight.
Purely by instinct and his recollection of the aspect of things the
night before, he had to clear telegraph wires and a railway bridge,
neither of which he could possibly see at that hour. His engine, too,
was faltering, and it was obvious to those who witnessed his start that
its note was far from perfect.
At 3.50 he was over Nuneaton and making good progress; between
Atherstone and Lichfield the wind caught him and the engine failed more
and more, until at 4.13 in the morning he was forced to come to earth,
having covered 6 miles less distance than in his first attempt. It was
purely a case of engine failure, for, with full power, he would have
passed over Paulhan just as the latter was preparing for the restart.
Taking into consideration the two machines, there is little doubt
that Grahame White showed the greater flying skill, although he lost
the prize. After landing and hearing of Paulhan’s victory, on which he
wired congratulations, he made up his mind to fly to Manchester within
the 24 hours. He started at 5 o’clock in the afternoon from Polesworth,
his landing place, but was forced to land at 5.30 at Whittington, where
he had landed on the previous Saturday. The wind, which had forced his
descent, fell again and permitted of starting once more; on this third
stage he reached Lichfield, only to make his final landing at 7.15
p.m., near the Trent Valley station. The defective running of the Gnome
engine prevented his completing the course, and his Farman machine had
to be brought back to London by rail.
The presentation of the prize to Paulhan was made the occasion for
the announcement of a further competition, consisting of a 1,000 mile
flight round a part of Great Britain. In this, nineteen competitors
started, and only four finished; the end of the race was a great
fight between Beaumont and Vedrines, both of whom scorned weather
conditions in their determination to win. Beaumont made the distance
in a flying time of 22 hours 28 minutes 19 seconds, and Vedrines
covered the journey in a little over 23½ hours. Valentine came third
on a Deperdussin monoplane and S. F. Cody on his Cathedral biplane was
fourth. This was in 1911, and by that time heavier-than-air flight had
so far advanced that some pilots had had war experience in the Italian
campaign in Tripoli, while long cross-country flights were an everyday
event, and bad weather no longer counted.
XVII
A SUMMARY, TO 1911
There is so much overlapping in the crowded story of the first years
of successful power-driven flight that at this point it is advisable
to make a concise chronological survey of the chief events of the
period of early development, although much of this is of necessity
recapitulation. The story begins, of course, with Orville Wright’s
first flight of 852 feet at Kitty Hawk on December 19th, 1903. The
next event of note was Wright’s flight of 11.12 miles in 18 minutes
9 seconds at Dayton, Ohio, on September 26th, 1905, this being the
first officially recorded flight. On October 4th of the same year,
Wright flew 20.75 miles in 33 minutes 17 seconds, this being the first
flight of over 20 miles ever made. Then on September 14th, 1906,
Alberto Santos-Dumont made a flight of eight seconds on the second
heavier-than-air machine he had constructed. It was a big box-kite-like
machine; this was the second power-driven aeroplane in Europe to
fly, for although Santos-Dumont’s first machine produced in 1905 was
reckoned an unsuccessful design, it had actually got off the ground for
brief periods. Louis Bleriot came into the ring on April 5th, 1907,
with a first flight of 6 seconds on a Bleriot monoplane, his eighth but
first successful construction.
Henry Farman made his first appearance in the history of aviation
with a flight of 935 feet on a Voisin biplane on October 15th, 1907.
On October 25th, in a flight of 2,530 feet, he made the first recorded
turn in the air, and on March 29th, 1908, carrying Leon Delagrange on
a Voisin biplane, he made the first passenger flight. On April 10th of
this year, Delagrange, in flying 1½ miles, made the first flight in
Europe exceeding a mile in distance. He improved on this by flying 10½
miles at Milan on June 22nd, while on July 8th, at Turin, he took up
Madame Peltier, the first woman to make an aeroplane flight.
Wilbur Wright, coming over to Europe, made his first appearance on the
Continent with a flight of 1¾ minutes at Hunaudieres, France, on August
8th, 1908. On September 6th, at Châlons, he flew for 1 hour 4 minutes
26 seconds with a passenger, this being the first flight in which an
hour in the air was exceeded with a passenger on board.
On September 12th, 1908, Orville Wright, flying at Fort Meyer,
U.S.A., with Lieut. Selfridge as passenger, crashed his machine,
suffering severe injuries, while Selfridge was killed. This was
the first aeroplane fatality. On October 30th, 1908, Farman made
the first cross-country flight, covering the distance of 17 miles
between Bouy and Rheims. The next day, Louis Bleriot, in flying from
Toury to Artenay, made two landings _en route_, this being the first
cross-country flight with landings. On the last day of the year, Wilbur
Wright won the Michelin Cup at Auvours with a flight of 90 miles,
which, lasting 2 hours 20 minutes 23 seconds, exceeded 2 hours in the
air for the first time.
On January 2nd, 1909, S. F. Cody opened the New Year by making the
first observed flight at Farnborough on a British Army aeroplane. It
was not until July 18th of 1909 that the first European height record
deserving of mention was put up by Paulhan, who achieved a height of
450 feet on a Voisin biplane. This preceded Latham’s first attempt to
fly the Channel by two days, and five days later, on the 25th of the
month, Bleriot made the first Channel crossing. The Rheims Meeting
followed on August 22nd, and it was a great day for aviation when nine
machines were seen in the air at once. It was here that Farman, with a
118 mile flight, first exceeded the hundred miles, and Latham raised
the height record officially to 500 feet, though actually he claimed to
have reached 1,200 feet. On September 8th, Cody, flying from Aldershot,
made a 40 mile journey, setting up a new cross-country record. On
October 19th the Comte de Lambert flew from Juvisy to Paris, rounded
the Eiffel Tower and flew back. J. T. C. Moore-Brabazon made the first
circular mile flight by a British aviator on an all-British machine in
Great Britain, on October 30th, flying a Short biplane with a Green
engine. Paulhan, flying at Brooklands on November 2nd, accomplished 96
miles in 2 hours 48 minutes, creating a British distance record; on
the following day, Henry Farman made a flight of 150 miles in 4 hours
22 minutes at Mourmelon, and on the 5th of the month, Paulhan, flying
a Farman biplane, made a world’s height record of 977 feet. This,
however, was not to stand long, for Latham got up to 1,560 feet on an
Antoinette at Mourmelon on December 1st. December 31st witnessed the
first flight in Ireland, made by H. Ferguson on a monoplane which he
himself had constructed at Downshire Park, Lisburn.
These, thus briefly summarised, are the principal events up to the end
of 1909. 1910 opened with tragedy, for on January 4th Leon Delagrange,
one of the greatest pilots of his time, was killed while flying at
Pau. The machine was the Bleriot XI which Delagrange had used at the
Doncaster meeting, and to which Delagrange had fitted a 50 horse-power
Gnome engine, increasing the speed of the machine from its original
30 to 45 miles per hour. With the Rotary Gnome engine there was of
necessity a certain gyroscopic effect, the strain of which proved too
much for the machine. Delagrange had come to assist in the inauguration
of the Croix d’Hins aerodrome, and had twice lapped the course at
a height of about 60 feet. At the beginning of the third lap, the
strain of the Gnome engine became too great for the machine; one wing
collapsed as if the stay wires had broken, and the whole machine turned
over and fell, killing Delagrange.
On January 7th Latham, flying at Mourmelon, first made the vertical
kilometre and dedicated the record to Delagrange, this being the day
of his friend’s funeral. The record was thoroughly authenticated by
a large registering barometer which Latham carried, certified by the
officials of the French Aero Club. Three days later Paulhan, who was at
Los Angeles, California, raised the height record to 4,146 feet.
On January 25th the Brussels Exhibition opened, when the Antoinette
monoplane, the Gaffaux and Hanriot monoplanes, together with the
d’Hespel aeroplane, were shown; there were also the dirigible Belgica
and a number of interesting aero engines, including a German airship
engine and a four-cylinder 50 horse-power Miesse, this last air-cooled
by means of fans driving a current of air through air jackets
surrounding fluted cylinders.
On April 2nd Hubert Le Blon, flying a Bleriot with an Anzani engine,
was killed while flying over the water. His machine was flying quite
steadily, when it suddenly heeled over and came down sideways into the
sea; the motor continued running for some seconds and the whole machine
was drawn under water. When boats reached the spot, Le Blon was found
lying back in the driving seat floating just below the surface. He had
done good flying at Doncaster, and at Heliopolis had broken the world’s
speed records for 5 and 10 kilometres. The accident was attributed to
fracture of one of the wing stay wires when running into a gust of wind.
The next notable event was Paulhan’s London-Manchester flight, of which
full details have already been given. In May Captain Bertram Dickson,
flying at the Tours meeting, beat all the Continental fliers whom
he encountered, including Chavez, the Peruvian, who later made the
first crossing of the Alps. Dickson was the first British winner of
international aviation prizes.
C. S. Rolls, of whom full details have already been given, was killed
at Bournemouth on July 12th, being the first British aviator of note to
be killed in an aeroplane accident. His return trip across the Channel
had taken place on June 2nd. Chavez, who was rapidly leaping into
fame, as a pilot, raised the British height record to 5,750 feet while
flying at Blackpool on August 3rd. On the 11th of that month, Armstrong
Drexel, flying a Bleriot, made a world’s height record of 6,745 feet.
It was in 1910 that the British War Office first began fully to realise
that there might be military possibilities in heavier-than-air flying.
C. S. Rolls had placed a Wright biplane at the disposal of the military
authorities, and Cody, as already recorded, had been experimenting with
a biplane type of his own for some long period. Such development as was
achieved was mainly due to the enterprise and energy of Colonel J. E.
Capper, C.B., appointed to the superintendency of the Balloon Factory
and Balloon School at Farnborough in 1906. Colonel Capper’s retirement
in 1910 brought (then) Mr Mervyn O’Gorman to command, and by that
time the series of successes of the Cody biplane, together with the
proved efficiency of the aeroplane in various civilian meetings, had
convinced the British military authorities that the mastery of the air
did not lie altogether with dirigible airships, and it may be said that
in 1910 the British War Office first began seriously to consider the
possibilities of the aeroplane, though two years more were to elapse
before the formation of the Royal Flying Corps marked full realisation
of its value.
[Illustration: Chavez flying across the Alps.]
A triumph and a tragedy were combined in September of 1910. On the
23rd of the month, Georges Chavez set out to fly across the Alps on
a Bleriot monoplane. Prizes had been offered by the Milan Aviation
Committee for a flight from Brigue in Switzerland over the Simplon
Pass to Milan, a distance of 94 miles with a minimum height of 6,600
feet above sea level. Chavez started at 1.30 p.m. on the 23rd, and
41 minutes later he reached Domodossola, 25 miles distant. Here he
descended, numbed with the cold of the journey; it was said that the
wings of his machine collapsed when about 30 feet from the ground, but
however this may have been, he smashed the machine on landing, and
broke both legs, in addition to sustaining other serious injuries. He
lay in hospital until the 27th September, when he died, having given
his life to the conquest of the Alps. His death in the moment of
success was as great a tragedy as were those of Pilcher and Lilienthal.
The day after Chavez’s death, Maurice Tabuteau flew across the
Pyrenees, landing in the square at Biarritz. On December 30th,
Tabuteau made a flight of 365 miles in 7 hours 48 minutes. Farman,
on December 18th, had flown for over 8 hours, but his total distance
was only 282 miles. The autumn of this year was also noteworthy for
the fact that aeroplanes were first successfully used in the French
Military Manœuvres. The British War Office, by the end of the year, had
bought two machines, a military type Farman and a Paulhan, ignoring
British experimenters and aeroplane builders of proved reliability.
These machines, added to an old Bleriot two-seater, appear to have
constituted the British aeroplane fleet of the period.
There were by this time three main centres of aviation in England,
apart from Cody, alone on Laffan’s Plain. These three were Brooklands,
Hendon, and the Isle of Sheppey, and of the three Brooklands was
chief. Here such men as Graham Gilmour, Rippen, Leake, Wickham, and
Thomas persistently experimented. Hendon had its own little group, and
Shellbeach, Isle of Sheppey, held such giants of those days as C. S.
Rolls and Moore Brabazon, together with Cecil Grace and Rawlinson. One
or other, and sometimes all of these were deserted on the occasion of
some meeting or other, but they were the points where the spade work
was done, Brooklands taking chief place. ‘If you want the early history
of flying in England, it is there,’ one of the early school remarked,
pointing over toward Brooklands course.
1911 inaugurated a new series of records of varying character. On
the 17th January, E. B. Ely, an American, flew from the shore of San
Francisco to the U.S. cruiser _Pennsylvania_, landing on the cruiser,
and then flew back to the shore. The British military designing of
aeroplanes had been taken up at Farnborough by G. H. de Havilland, who
by the end of January was flying a machine of his own design, when he
narrowly escaped becoming a casualty through collision with an obstacle
on the ground, which swept the undercarriage from his machine.
A list of certified pilots of the countries of the world was issued
early in 1911, showing certificates granted up to the end of 1910.
France led the way easily with 353 pilots; England came next with 57,
and Germany next with 46; Italy owned 32, Belgium 27, America 26,
and Austria 19; Holland and Switzerland had 6 aviators apiece, while
Denmark followed with 3, Spain with 2, and Sweden with 1. The first
certificate in England was that of J. T. C. Moore-Brabazon, while Louis
Bleriot was first on the French list and Glenn Curtiss, first holder of
an American certificate, also held the second French brevet.
On the 7th March, Eugene Renaux won the Michelin Grand Prize by flying
from the French Aero Club ground at St Cloud and landing on the Puy de
Dome. The landing, which was one of the conditions of the prize, was
one of the most dangerous conditions ever attached to a competition;
it involved dropping on to a little plateau 150 yards square, with
a possibility of either smashing the machine against the face of the
mountain, or diving over the edge of the plateau into the gulf beneath.
The length of the journey was slightly over 200 miles and the height of
the landing point 1,465 metres, or roughly 4,500 feet above sea-level.
Renaux carried a passenger, Doctor Senoucque, a member of Charcot’s
South Polar Expedition.
The 1911 Aero Exhibition held at Olympia bore witness to the enormous
strides made in construction, more especially by British designers,
between 1908 and the opening of the Show. The Bristol Firm showed three
machines, including a military biplane, and the first British-built
biplane with tractor screw. The Cody biplane, with its enormous size
rendering it a prominent feature of the show, was exhibited. Its
designer anticipated later engines by expressing his desire for a motor
of 150 horse-power, which in his opinion was necessary to get the best
results from the machine. The then famous Dunne monoplane was exhibited
at this show, its planes being V-shaped in plan, with apex leading.
It embodied the results of very lengthy experiments carried out both
with gliders and power-driven machines by Colonel Capper, Lieut. Gibbs,
and Lieut. Dunne, and constituted the longest step so far taken in the
direction of inherent stability.
Such forerunners of the notable planes of the war period as the Martin
Handasyde, the Nieuport, Sopwith, Bristol, and Farman machines, were
features of the show; the Handley-Page monoplane, with a span of 32
feet over all, a length of 22 feet, and a weight of 422 lbs., bore no
relation at all to the twin-engined giant which later made this firm
famous. In the matter of engines, the principal survivals to the
present day, of which this show held specimens, were the Gnome, Green,
Renault air-cooled, Mercedes four-cylinder dirigible engine of 115
horse-power, and 120 horse-power Wolseley of eight cylinders for use
with dirigibles.
On April 12th of 1911, Paprier, instructor at the Bleriot school at
Hendon, made the first non-stop flight between London and Paris. He
left the aerodrome at 1.37 p.m., and arrived at Issy-les-Moulineaux
at 5.33 p.m., thus travelling 250 miles in a little under 4 hours. He
followed the railway route practically throughout, crossing from Dover
to nearly opposite Calais, keeping along the coast to Boulogne, and
then following the Nord Railway to Amiens, Beauvais, and finally Paris.
In May, the Paris-Madrid race took place; Vedrines, flying a Morane
biplane, carried off the prize by first completing the distance of 732
miles. The Paris-Rome race of 916 miles was won in the same month by
Beaumont, flying a Bleriot monoplane. In July, Kœnig won the German
National Circuit race of 1,168 miles on an Albatross biplane. This was
practically simultaneous with the Circuit of Britain won by Beaumont,
who covered 1,010 miles on a Bleriot monoplane, having already won the
Paris-Brussels-London-Paris Circuit of 1,080 miles, this also on a
Bleriot. It was in August that a new world’s height record of 11,152
feet was set up by Captain Felix at Etampes, while on the 7th of the
month Renaux flew nearly 600 miles on a Maurice Farman machine in 12
hours. Cody and Valentine were keeping interest alive in the Circuit of
Britain race, although this had long been won, by determinedly plodding
on at finishing the course.
[Illustration: Army Aeroplane Tests on Salisbury Plain, 2nd August,
1912. Védrines passing Cody’s hangar.]
On September 9th, the first aerial post was tried between Hendon and
Windsor, as an experiment in sending mails by aeroplane. Gustave Hamel
flew from Hendon to Windsor and back in a strong wind. A few days
later, Hamel went on strike, refusing to carry further mails unless
the promoters of the Aerial Postal Service agreed to pay compensation
to Hubert, who fractured both his legs on the 11th of the month while
engaged in aero postal work. The strike ended on September 25th, when
Hamel resumed mail-carrying in consequence of the capitulation of the
Postmaster-General, who agreed to set aside £500 as compensation to
Hubert.
September also witnessed the completion in America of a flight across
the Continent, a distance of 2,600 miles. The only competitor who
completed the full distance was C. P. Rogers, who was disqualified
through failing to comply with the time limit. Rogers needed so many
replacements to his machine on the journey that, expressing it in
American fashion, he arrived with practically a different aeroplane
from that with which he started.
With regard to the aerial postal service, analysis of the matter
carried and the cost of the service seemed to show that with a special
charge of one shilling for letters and sixpence for post cards, the
revenue just balanced the expenditure. It was not possible to keep to
the time-table as, although the trials were made in the most favourable
season of the year, aviation was not sufficiently advanced to admit of
facing all weathers and complying with time-table regulations.
French military aeroplane trials took place at Rheims in October,
the noteworthy machines being Antoinette, Farman, Nieuport, and
Deperdussin. The tests showed the Nieuport monoplane with Gnome
motor as first in position; the Breguet biplane was second, and the
Deperdussin monoplanes third. The first five machines in order of merit
were all engined with the Gnome motor.
The records quoted for 1911 form the best evidence that can be given of
advance in design and performance during the year. It will be seen that
the days of the giants were over; design was becoming more and more
standardised and aviation not so much a matter of individual courage
and even daring, as of the reliability of the machine and its engine.
This was the first year in which the twin-engined aeroplane made its
appearance, and it was the year, too, in which flying may be said to
have grown so common that the ‘meetings’ which began with Rheims were
hardly worth holding, owing to the fact that increase in height and
distance flown rendered it no longer necessary for a would-be spectator
of a flight to pay half a crown and enter an enclosure. Henceforth,
flying as a spectacle was very little to be considered; its commercial
aspects were talked of, and to a very slight degree exploited, but,
more and more, the fact that the aeroplane was primarily an engine
of war, and the growing German menace against the peace of the
world combined to point the way of speediest development, and the
arrangements for the British Military Trials to be held in August,
1912, showed that even the British War Office was waking up to the
potentialities of this new engine of war.
XVIII
A SUMMARY, TO 1914
Consideration of the events in the years immediately preceding the
War must be limited to as brief a summary as possible, this not
only because the full history of flying achievements is beyond the
compass of any single book, but also because, viewing the matter in
perspective, the years 1903–1911 show up as far more important as
regards both design and performance. From 1912 to August of 1914, the
development of aeronautics was hindered by the fact that it had not
progressed far enough to form a real commercial asset in any country.
The meetings which drew vast concourses of people to such places as
Rheims and Bournemouth may have been financial successes at first, but,
as flying grew more common and distances and heights extended, a great
many people found it other than worth while to pay for admission to an
aerodrome. The business of taking up passengers for pleasure flights
was not financially successful, and, although schemes for commercial
routes were talked of, the aeroplane was not sufficiently advanced
to warrant the investment of hard cash in any of these projects.
There was a deadlock; further development was necessary in order to
secure financial aid, and at the same time financial aid was necessary
in order to secure further development. Consequently, neither was
forthcoming.
This is viewing the matter in a broad and general sense; there were
firms, especially in France, but also in England and America, which
looked confidently for the great days of flying to arrive, and regarded
their sunk capital as investment which would eventually bring its due
return. But when one looks back on those years, the firms in question
stand out as exceptions to the general run of people, who regarded
aeronautics as something extremely scientific, exceedingly dangerous,
and very expensive. The very fame that was attained by such pilots as
became casualties conduced to the advertisement of every death, and
the dangers attendant on the use of heavier-than-air machines became
greatly exaggerated; considering the matter as one of number of miles
flown, even in the early days, flying exacted no more toll in human
life than did railways or road motors in the early stages of their
development. But to take one instance, when C. S. Rolls was killed at
Bournemouth by reason of a faulty tail-plane, the fact was shouted to
the whole world with almost as much vehemence as characterised the
announcement of the _Titanic_ sinking in mid-Atlantic.
[Illustration: Army Aeroplane Tests on Salisbury Plain.
Cody on his new aeroplane.]
Even in 1911 the deadlock was apparent; meetings were falling off in
attendance, and consequently in financial benefit to the promoters;
there remained, however, the knowledge--for it was proved past
question--that the aeroplane in its then stage of development was a
necessity to every army of the world. France had shown this by the more
than interest taken by the French Government in what had developed into
an Air Section of the French army; Germany, of course, was hypnotised
by Count Zeppelin and his dirigibles, to say nothing of the Parsevals
which had been proved useful military accessories; in spite of
this, it was realised in Germany that the aeroplane also had its place
in military affairs. England came into the field with the military
aeroplane trials of August 1st to 15th, 1912, barely two months after
the founding of the Royal Flying Corps.
When the R.F.C. was founded--and in fact up to two years after its
founding--in no country were the full military potentialities of the
aeroplane realised; it was regarded as an accessory to cavalry for
scouting more than as an independent arm; the possibilities of bombing
were very vaguely considered, and the fact that it might be possible to
shoot from an aeroplane was hardly considered at all. The conditions of
the British Military Trials of 1912 gave to the War Office the option
of purchasing for £1,000 any machine that might be awarded a prize.
Machines were required, among other things, to carry a useful load of
350 lbs. in addition to equipment, with fuel and oil for 4½ hours; thus
loaded, they were required to fly for 3 hours, attaining an altitude of
4,500 feet, maintaining a height of 1,500 feet for 1 hour, and climbing
1,000 feet from the ground at a rate of 200 feet per minute, ‘although
300 feet per minute is desirable.’ They had to attain a speed of not
less than 55 miles per hour in a calm, and be able to plane down to the
ground in a calm from not more than 1,000 feet with engine stopped,
traversing 6,000 feet horizontal distance. For those days, the landing
demands were rather exacting; the machine should be able to rise
without damage from long grass, clover, or harrowed land, in 100 yards
in a calm, and should be able to land without damage on any cultivated
ground, including rough ploughed land, and, when landing on smooth turf
in a calm, be able to pull up within 75 yards of the point of first
touching the ground. It was required that pilot and observer should
have as open a view as possible to front and flanks, and they should be
so shielded from the wind as to be able to communicate with each other.
These are the main provisions out of the set of conditions laid down
for competitors, but a considerable amount of leniency was shown by the
authorities in the competition, who obviously wished to try out every
machine entered and see what were its capabilities.
The beginning of the competition consisted in assembling the machines
against time from road trim to flying trim. Cody’s machine, which was
the only one to be delivered by air, took 1 hour and 35 minutes to
assemble; the best assembling time was that of the Avro, which was got
into flying trim in 14 minutes 30 seconds. This machine came to grief
with Lieut. Parke as pilot, on the 7th, through landing at very high
speed on very bad ground; a securing wire of the undercarriage broke in
the landing, throwing the machine forward on to its nose and then over
on its back. Parke was uninjured, fortunately; the damaged machine was
sent off to Manchester for repair and was back again on the 16th of
August.
It is to be noted that by this time the Royal Aircraft Factory was
building aeroplanes of the B.E. and F.E. types, but at the same time
it is also to be noted that British military interest in engines
was not sufficient to bring them up to the high level attained by
the planes, and it is notorious that even the outbreak of war found
England incapable of providing a really satisfactory aero engine. In
the 1912 Trials, the only machines which actually completed all their
tests were the Cody biplane, the French Deperdussin, the Hanriot, two
Bleriots and a Maurice Farman. The first prize of £4,000, open to all
the world, went to F. S. Cody’s British-built biplane, which complied
with all the conditions of the competition and well earned its official
acknowledgment of supremacy. The machine climbed at 280 feet per minute
and reached a height of 5,000 feet, while in the landing test, in spite
of its great weight and bulk, it pulled up on grass in 56 yards. The
total weight was 2,690 lbs. when fully loaded, and the total area of
supporting surface was 500 square feet; the motive power was supplied
by a six-cylinder 120 horse-power Austro-Daimler engine. The second
prize was taken by A. Deperdussin for the French-built Deperdussin
monoplane. Cody carried off the only prize awarded for a British-built
plane, this being the sum of £1,000, and consolation prizes of £500
each were awarded to the British Deperdussin Company and The British
and Colonial Aeroplane Company, this latter soon to become famous as
makers of the Bristol aeroplane, of which the war honours are still
fresh in men’s minds.
While these trials were in progress Audemars accomplished the first
flight between Paris and Berlin, setting out from Issy early in the
morning of August 18th, landing at Rheims to refill his tanks within
an hour and a half, and then coming into bad weather which forced him
to land successively at Mezieres, Laroche, Bochum, and finally nearly
Gersenkirchen, where, owing to a leaky petrol tank, the attempt to win
the prize offered for the first flight between the two capitals had to
be abandoned after 300 miles had been covered, as the time limit was
definitely exceeded. Audemars determined to get through to Berlin, and
set off at 5 in the morning of the 19th, only to be brought down by
fog; starting off again at 9.15 he landed at Hanover, was off again at
1.35, and reached the Johannisthal aerodrome in the suburbs of Berlin
at 6.48 that evening.
As early as 1910 the British Government possessed some ten aeroplanes,
and in 1911 the force developed into the Army Air Battalion, with the
aeroplanes under the control of Major J. H. Fulton, R.F.A. Toward the
end of 1911 the Air Battalion was handed over to (then) Brig.-Gen. D.
Henderson, Director of Military Training. On June 6th, 1912, the Royal
Flying Corps was established with a military wing under Major F. H.
Sykes and a naval wing under Commander C. R. Samson. A joint Naval and
Military Flying School was established at Upavon with Captain Godfrey
M. Paine, R.N., as Commandant and Major Hugh Trenchard as Assistant
Commandant. The Royal Aircraft Factory brought out the B.E. and F.E.
types of biplane, admittedly superior to any other British design of
the period, and an Aircraft Inspection Department was formed under
Major J. H. Fulton. The military wing of the R.F.C. was equipped almost
entirely with machines of Royal Aircraft Factory design, but the Navy
preferred to develop British private enterprise by buying machines from
private firms. On July 1st, 1914, the establishment of the Royal Naval
Air Service marked the definite separation of the military and naval
sides of British aviation, but the Central Flying School at Upavon
continued to train pilots for both services.
[Illustration: Army Aeroplane Tests on Salisbury Plain, 2nd August,
1912.
The new Army aeroplane.]
It is difficult at this length of time, so far as the military wing
was concerned, to do full justice to the spade work done by
Major-General Sir David Henderson in the early days. Just before war
broke out, British military air strength consisted officially of eight
squadrons, each of 12 machines and 13 in reserve, with the necessary
complement of road transport. As a matter of fact, there were three
complete squadrons and a part of a fourth which constituted the force
sent to France at the outbreak of war. The value of General Henderson’s
work lies in the fact that, in spite of official stinginess and meagre
supplies of every kind, he built up a skeleton organisation so elastic
and so well thought out that it conformed to war requirements as well
as even the German plans fitted in with their aerial needs. On the 4th
of August, 1914, the nominal British air strength of the military wing
was 179 machines. Of these, 82 machines proceeded to France, landing
at Amiens and flying to Maubeuge to play their part in the great
retreat with the British Expeditionary Force, in which they suffered
heavy casualties both in personnel and machines. The history of their
exploits, however, belongs to the War period.
The development of the aeroplane between 1912 and 1914 can be judged
by comparison of the requirements of the British War Office in 1912
with those laid down in an official memorandum issued by the War Office
in February, 1914. This latter called for a light scout aeroplane, a
single-seater, with fuel capacity to admit of 300 miles range and a
speed range of from 50 to 85 miles per hour. It had to be able to climb
3,500 feet in five minutes, and the engine had to be so constructed
that the pilot could start it without assistance. At the same time,
a heavier type of machine for reconnaissance work was called for,
carrying fuel for a 200 mile flight with a speed range of between 35
and 60 miles per hour, carrying both pilot and observer. It was to be
equipped with a wireless telegraphy set, and be capable of landing
over a 30 foot vertical obstacle and coming to rest within a hundred
yards’ distance from the obstacle in a wind of not more than 15 miles
per hour. A third requirement was a heavy type of fighting aeroplane
accommodating pilot and gunner with machine gun and ammunition, having
a speed range of between 45 and 75 miles per hour and capable of
climbing 3,500 feet in 8 minutes. It was required to carry fuel for
a 300 mile flight and to give the gunner a clear field of fire in
every direction up to 30 degrees on each side of the line of flight.
Comparison of these specifications with those of the 1912 trials
will show that although fighting, scouting, and reconnaissance types
had been defined, the development of performance compared with the
marvellous development of the earlier years of achieved flight was
small.
Yet the records of those years show that here and there an outstanding
design was capable of great things. On the 9th September, 1912,
Vedrines, flying a Deperdussin monoplane at Chicago, attained a speed
of 105 miles an hour. On August 12th G. de Havilland took a passenger
to a height of 10,560 feet over Salisbury Plain, flying a B.E. biplane
with a 70 horse-power Renault engine. The work of de Havilland may be
said to have been the principal influence in British military aeroplane
design, and there is no doubt that his genius was in great measure
responsible for the excellence of the early B.E. and F.E. types.
On the 31st May, 1913, H. G. Hawker, flying at Brooklands, reached
a height of 11,450 feet on a Sopwith biplane engined with an 80
horse-power Gnome engine. On June 16th, with the same type of machine
and engine, he achieved 12,900 feet. On the 2nd October, in the same
year, a Grahame White biplane with 120 horse-power Austro-Daimler
engine, piloted by Louis Noel, made a flight of just under 20 minutes
carrying 9 passengers. In France a Nieuport monoplane piloted by G.
Legagneaux attained a height of 6,120 metres, or just over 20,070 feet,
this being the world’s height record. It is worthy of note that of the
world’s aviation records as passed by the International Aeronautical
Federation up to June 30th, 1914, only one, that of Noel, is credited
to Great Britain.
Just as records were made abroad, with one exception, so were the
really efficient engines. In England there was the Green engine, but
the outbreak of war found the Royal Flying Corps with 80 horse-power
Gnomes, 70 horse-power Renaults, and one or two Antoinette motors, but
not one British, while the Royal Naval Air Service had got 20 machines
with engines of similar origin, mainly land planes in which the wheeled
undercarriages had been replaced by floats. France led in development,
and there is no doubt that at the outbreak of war, the French military
aeroplane service was the best in the world. It was mainly composed of
Maurice Farman two-seater biplanes and Bleriot monoplanes--the latter
type banned for a period on account of a number of serious accidents
that took place in 1912.
America had its Army Aviation School, and employed Burgess-Wright
and Curtiss machines for the most part. In the pre-war years, once
the Wright Brothers had accomplished their task, America’s chief
accomplishment consisted in the development of the ‘Flying Boat,’
alternatively named with characteristic American clumsiness, ‘The
Hydro-Aeroplane.’ In February of 1911, Glenn Curtiss attached a float
to a machine similar to that with which he won the first Gordon-Bennett
Air Contest and made his first flying boat experiment. From this
beginning he developed the boat form of body which obviated the use and
troubles of floats--his hydroplane became its own float.
Mainly owing to greater engine reliability the duration records
steadily increased. By September of 1912 Fourny, on a Maurice Farman
biplane, was able to accomplish a distance of 628 miles without a
landing, remaining in the air for 13 hours 17 minutes and just over
57 seconds. By 1914 this was raised by the German aviator, Landemann,
to 21 hours 48¾ seconds. The nature of this last record shows that
the factors in such a record had become mere engine endurance, fuel
capacity, and capacity of the pilot to withstand air conditions for a
prolonged period, rather than any exceptional flying skill.
[Illustration: Flight of full-size Langley Aerodrome, piloted by Glenn
H. Curtiss, 2nd June 1914, at Hammondsport, N.Y.
Original machine and engine, with the addition of pontoons which
weighed 300 lbs.]
Let these years be judged by the records they produced, and even then
they are rather dull. The glory of achievement such as characterised
the work of the Wright Brothers, of Bleriot, and of the giants of
the early days, had passed; the splendid courage, the patriotism
and devotion of the pilots of the War period had not yet come to
being. There was progress, past question, but it was mechanical,
hardly ever inspired. The study of climatic conditions was definitely
begun and aeronautical metereology came to being, while another
development already noted was the fitting of wireless telegraphy to
heavier-than-air machines, as instanced in the British War Office
specification of February, 1914. These, however, were inevitable;
it remained for the War to force development beyond the inevitable,
producing in five years that which under normal circumstances might
easily have occupied fifty--the aeroplane of to-day; for, as already
remarked, there was a deadlock, and any survey that may be made of
the years 1912–1914, no matter how superficial, must take it into
account with a view to retaining correct perspective in regard to the
development of the aeroplane.
There is one story of 1914 that must be included, however briefly, in
any record of aeronautical achievement, since it demonstrates past
question that to Professor Langley really belongs the honour of having
achieved a design which would ensure actual flight, although the
series of accidents which attended his experiments gave to the Wright
Brothers the honour of first leaving the earth and descending without
accident in a power-driven heavier-than-air machine. In March, 1914,
Glenn Curtiss was invited to send a flying boat to Washington for
the celebration of ‘Langley Day,’ when he remarked, ‘I would like to
put the Langley aeroplane itself in the air.’ In consequence of this
remark, Secretary Walcot of the Smithsonian Institution authorised
Curtiss to re-canvas the original Langley aeroplane and launch it
either under its own power or with a more recent engine and propeller.
Curtiss completed this, and had the machine ready on the shores of Lake
Keuka, Hammondsport, N.Y., by May. The main object of these renewed
trials was to show whether the original Langley machine was capable
of sustained free flight with a pilot, and a secondary object was to
determine more fully the advantages of the tandem monoplane type; thus
the aeroplane was first flown as nearly as possible in its original
condition, and then with such modifications as seemed desirable. The
only difference made for the first trials consisted in fitting floats
with connecting trusses; the steel main frame, wings, rudders, engine,
and propellers were substantially as they had been in 1903. The pilot
had the same seat under the main frame and the same general system of
control. He could raise or lower the craft by moving the rear rudder up
and down; he could steer right or left by moving the vertical rudder.
He had no ailerons nor wing-warping mechanism, but for lateral balance
depended on the dihedral angle of the wings and upon suitable movements
of his weight or of the vertical rudder.
After the adjustments for actual flight had been made in the Curtiss
factory, according to the minute descriptions contained in the Langley
Memoir on Mechanical Flight, the aeroplane was taken to the shore of
Lake Keuka, beside the Curtiss hangars, and assembled for launching.
On a clear morning (May 28th) and in a mild breeze, the craft was
lifted on to the water by a dozen men and set going, with Mr Curtiss
at the steering wheel, esconced in the little boat-shaped car under
the forward part of the frame. The four-winged craft, pointed somewhat
across the wind, went skimming over the wavelets, then automatically
headed into the wind, rose in level poise, soared gracefully for
150 feet, and landed softly on the water near the shore. Mr Curtiss
asserted that he could have flown farther, but, being unused to the
machine, imagined that the left wings had more resistance than the
right. The truth is that the aeroplane was perfectly balanced in wing
resistance, but turned on the water like a weather vane, owing to the
lateral pressure on its big rear rudder. Hence in future experiments
this rudder was made turnable about a vertical axis, as well as about
the horizontal axis used by Langley. Henceforth the little vertical
rudder under the frame was kept fixed and inactive.[7]
That the Langley aeroplane was subsequently fitted with an 80
horse-power Curtiss engine and successfully flown is of little interest
in such a record as this, except for the fact that with the weight
nearly doubled by the new engine and accessories the machine flew
successfully, and demonstrated the perfection of Langley’s design by
standing the strain. The point that is of most importance is that the
design itself proved a success and fully vindicated Langley’s work. At
the same time, it would be unjust to pass by the fact of the flight
without according to Curtiss due recognition of the way in which he
paid tribute to the genius of the pioneer by these experiments.
XIX
THE WAR PERIOD--I
Full record of aeronautical progress and of the accomplishments of
pilots in the years of the War would demand not merely a volume, but a
complete library, and even then it would be barely possible to pay full
tribute to the heroism of pilots of the war period. There are names
connected with that period of which the glory will not fade, names
such as Bishop, Guynemer, Boelcke, Ball, Fonck, Immelmann, and many
others that spring to mind as one recalls the ‘Aces’ of the period.
In addition to the pilots, there is the stupendous development of the
machines--stupendous when the length of the period in which it was
achieved is considered.
The fact that Germany was best prepared in the matter of
heavier-than-air service machines in spite of the German faith in the
dirigible is one more item of evidence as to who forced hostilities.
The Germans came into the field with well over 600 aeroplanes, mainly
two-seaters of standardised design, and with factories back in the
Fatherland turning out sufficient new machines to make good the
losses. There were a few single-seater scouts built for speed, and the
two-seater machines were all fitted with cameras and bomb-dropping
gear. Manœuvres had determined in the German mind what should be the
uses of the air fleet; there was photography of fortifications and
field works; signalling by Véry lights; spotting for the guns, and
scouting for news of enemy movements. The methodical German mind
had arranged all this beforehand, but had not allowed for the fact
that opponents might take counter-measures which would upset the
over-perfect mechanism of the air service just as effectually as the
great march on Paris was countered by the genius of Joffre.
The French Air Force at the beginning of the War consisted of upwards
of 600 machines. These, unlike the Germans, were not standardised, but
were of many and diverse types. In order to get replacements quickly
enough, the factories had to work on the designs they had, and thus for
a long time after the outbreak of hostilities standardisation was an
impossibility. The versatility of a Latin race in a measure compensated
for this; from the outset, the Germans tried to overwhelm the French
Air Force, but failed, since they had not the numerical superiority,
nor--this equally a determining factor--the versatility and resource
of the French pilots. They calculated on a 50 per cent superiority to
ensure success; they needed more nearly 400 per cent, for the German
fought to rule, avoiding risks whenever possible, and definitely
instructed to save both machines and pilots wherever possible.
French pilots, on the other hand, ran all the risks there were, got
news of German movements, bombed the enemy, and rapidly worked up
a very respectable anti-aircraft force which, whatever it may have
accomplished in the way of hitting German planes, got on the German
pilots’ nerves.
It has already been detailed how Britain sent over 82 planes as its
contribution to the military aerial force of 1914. These consisted of
Farman, Caudron, and Short biplanes, together with Bleriot, Deperdussin
and Nieuport monoplanes, certain R.A.F. types, and other machines of
which even the name barely survives--the resourceful Yankee entitles
them ‘orphans.’ It is on record that the work of providing spares might
have been rather complicated but for the fact that there were none.
There is no doubt that the Germans had made study of aerial military
needs just as thoroughly as they had perfected their ground
organisation. Thus there were 21 illuminated aircraft stations in
Germany before the War, the most powerful being at Weimar, where a
revolving electric flash of over 27 million candle-power was located.
Practically all German aeroplane tests in the period immediately
preceding the War were of a military nature, and quite a number of
reliability tests were carried out just on the other side of the French
frontier. Night flying and landing were standardised items in the
German pilot’s course of instruction while they were still experimental
in other countries, and a system of signals was arranged which rendered
the instructional course as perfect as might be.
The Belgian contribution consisted of about twenty machines fit for
active service and another twenty which were more or less useful as
training machines. The material was mainly French, and the Belgian
pilots used it to good account until German numbers swamped them.
France, and to a small extent England, kept Belgian aviators supplied
with machines throughout the War.
The Italian Air Fleet was small, and consisted of French machines
together with a percentage of planes of Italian origin, of which the
design was very much a copy of French types. It was not until the War
was nearing its end that the military and naval services relied more
on the home product than on imports. This does not apply to engines,
however, for the F.I.A.T. and S.C.A.T. were equal to practically any
engine of Allied make, both in design and construction.
Russia spent vast sums in the provision of machines: the giant Sikorsky
biplane, carrying four 100 horse-power Argus motors, was designed by
a young Russian engineer in the latter part of 1913, and in its early
trials it created a world’s record by carrying seven passengers for
1 hour 54 minutes. Sikorsky also designed several smaller machines,
tractor biplanes on the lines of the British B.E. type, which were
very successful. These were the only home productions, and the imports
consisted mainly of French aeroplanes by the hundred, which got as
far as the docks and railway sidings and stayed there, while German
influence and the corruption that ruined the Russian Army helped to
lose the War. A few Russian aircraft factories were got into operation
as hostilities proceeded, but their products were negligible, and it is
not on record that Russia ever learned to manufacture a magneto.
The United States paid tribute to British efficiency by adopting
the British system of training for its pilots; 500 American cadets
were trained at the School of Military Aeronautics at Oxford, in
order to form a nucleus for the American aviation schools which were
subsequently set up in the United States and in France. As regards
production of craft, the designing of the Liberty engine and building
of over 20,000 aeroplanes within a year proves that America is a
manufacturing country, even under the strain of war.
There were three years of struggle for aerial supremacy, the combatants
being England and France against Germany, and the contest was neck
and neck all the way. Germany led at the outset with the standardised
two-seater biplanes manned by pilots and observers, whose training
was superior to that afforded by any other nation, while the machines
themselves were better equipped and fitted with accessories. All the
early German aeroplanes were designated Taube by the uninitiated,
and were formed with swept-back, curved wings very much resembling
the wings of a bird. These had obvious disadvantages, but the
standardisation of design and mass production of the German factories
kept them in the field for a considerable period, and they flew side by
side with tractor biplanes of improved design. For a little time, the
Fokker monoplane became a definite threat both to French and British
machines. It was an improvement on the Morane French monoplane, and
with a high-powered engine it climbed quickly and flew fast, doing a
good deal of damage for a brief period of 1915. Allied design got ahead
of it and finally drove it out of the air.
[Illustration: A Handley-Page ready to start on a bombing raid,
Dunkirk, 1st June, 1918.]
German equipment at the outset, which put the Allies at a disadvantage,
included a hand-operated magneto engine-starter and a small independent
screw which, mounted on one of the main planes, drove the dynamo used
for the wireless set. Cameras were fitted on practically every machine;
equipment included accurate compasses and pressure petrol gauges,
speed and height recording instruments, bomb-dropping fittings
and sectional radiators which facilitated repairs and gave maximum
engine efficiency in spite of variations of temperature. As counter
to these, the Allied pilots had resource amounting to impudence. In
the early days they carried rifles and hand grenades and automatic
pistols. They loaded their machines down, often at their own expense,
with accessories and fittings until their aeroplanes earned their
title of Christmas trees. They played with death in a way that shocked
the average German pilot of the War’s early stages, declining to
fight according to rule and indulging in the individual duels of the
air which the German hated. As Sir John French put it in one of his
reports, they established a personal ascendancy over the enemy, and in
this way compensated for their inferior material.
French diversity of design fitted in well with the initiative and
resource displayed by the French pilots. The big Caudron type was the
ideal bomber of the early days; Farman machines were excellent for
reconnaissance and artillery spotting; the Bleriots proved excellent
as fighting scouts and for aerial photography; the Nieuports made good
fighters, as did the Spads, both being very fast craft, as were the
Morane-Saulnier monoplanes, while the big Voisin biplanes rivalled the
Caudron machines as bombers.
The day of the Fokker ended when the British B.E.2.C. aeroplane came
to France in good quantities, and the F.E. type, together with the De
Havilland machines, rendered British aerial superiority a certainty.
Germany’s best reply--this was about 1916--was the Albatross biplane,
which was used by Captain Baron von Richthofen for his famous
travelling circus, manned by German star pilots and sent to various
parts of the line to hearten up German troops and aviators after any
specially bad strafe. Then there were the Aviatik biplane and the
Halberstadt fighting scout, a cleanly built and very fast machine with
a powerful engine with which Germany tried to win back superiority in
the third year of the War, but Allied design kept about three months
ahead of that of the enemy, once the Fokker had been mastered, and the
race went on. Spads and Bristol fighters, Sopwith scouts and F.E.’s
played their part in the race, and design was still advancing when
peace came.
The giant twin-engined Handley-Page bomber was tried out, proved
efficient, and justly considered better than anything of its kind that
had previously taken the field. Immediately after the conclusion of its
trials, a specimen of the type was delivered intact at Lille for the
Germans to copy, the innocent pilot responsible for the delivery doing
some great disservice to his own cause. The Gotha Wagon-Fabrik Firm
immediately set to work and copied the Handley-Page design, producing
the great Gotha bombing machine which was used in all the later raids
on England as well as for night work over the Allied lines.
How the War advanced design may be judged by comparison of the military
requirements given for the British Military Trials of 1912, with
performances of 1916 and 1917, when the speed of the faster machines
had increased to over 150 miles an hour and Allied machines engaged
enemy aircraft at heights ranging up to 22,000 feet. All pre-war
records of endurance, speed, and climb went by the board, as the race
for aerial superiority went on.
Bombing brought to being a number of crude devices in the first year
of the War. Allied pilots of the very early days carried up bombs
packed in a small box and threw them over by hand, while, a little
later, the bombs were strung like apples on wings and undercarriage, so
that the pilot who did not get rid of his load before landing risked an
explosion. Then came a properly designed carrying apparatus, crude but
fairly efficient, and with 1916 development had proceeded as far as the
proper bomb-racks with releasing gear.
Reconnaissance work developed, so that fighting machines went as
escort to observing squadrons and scouting operations were undertaken
up to 100 miles behind the enemy lines; out of this grew the art of
camouflage, when ammunition dumps were painted to resemble herds
of cows, guns were screened by foliage or painted to merge into a
ground scheme, and many other schemes were devised to prevent aerial
observation. Troops were moved by night for the most part, owing
to the keen eyes of the air pilots and the danger of bombs, though
occasionally the aviator had his chance. There is one story concerning
a British pilot who, on returning from a reconnaissance flight,
observed a German Staff car on the road under him; he descended and
bombed and machine-gunned the car until the German General and his
chauffeur abandoned it, took to their heels, and ran like rabbits.
Later still, when Allied air superiority was assured, there came
the phase of machine-gunning bodies of enemy troops from the air.
Disregarding all anti-aircraft measures, machines would sweep down and
throw battalions into panic or upset the military traffic along a road,
demoralising a battery or a transport train and causing as much damage
through congestion of traffic as with their actual machine-gun fire.
Aerial photography, too, became a fine art; the ordinary long focus
cameras were used at the outset with automatic plate changers, but
later on photographing aeroplanes had cameras of wide angle lens type
built into the fuselage. These were very simply operated, one lever
registering the exposure and changing the plate. In many cases, aerial
photographs gave information which the human eye had missed, and it is
noteworthy that photographs of ground showed when troops had marched
over it, while the aerial observer was quite unable to detect the marks
left by their passing.
[Illustration: Hoisting out a seaplane from the ‘Ark Royal,’ January,
1916.]
Some small mention must be made of seaplane activities, which, round
the European coasts involved in the War, never ceased. The submarine
campaign found in the spotting seaplane its greatest deterrent, and it
is old news now how even the deeply submerged submarines were easily
picked out for destruction from a height and the news wirelessed from
seaplane to destroyer, while in more than one place the seaplane
itself finished the task by bomb dropping. It was a seaplane that gave
Admiral Beatty the news that the whole German Fleet was out before
the Jutland Battle, news which led to a change of plans that very
nearly brought about the destruction of Germany’s naval power. For the
most part, the seaplanes of the War period were heavier than the land
machines and, in the opinion of the land pilots, were slow and clumsy
things to fly. This was inevitable, for their work demanded more solid
building and greater reliability. To put the matter into Hibernian
phrase, a forced landing at sea is a much more serious matter than on
the ground. Thus there was need for greater engine power, bigger
wing-spread to support the floats, and fuel tanks of greater capacity.
The flying boats of the later War period carried considerable crews,
were heavily armed, capable of withstanding very heavy weather, and
carried good loads of bombs on long cruises. Their work was not all
essentially seaplane work, for the R.N.A.S. was as well known as hated
over the German airship sheds in Belgium and along the Flanders coast.
As regards other theatres of War, they rendered valuable service from
the Dardanelles to the Rufiji River, at this latter place forming a
principal factor in the destruction of the cruiser _Königsberg_. Their
spotting work at the Dardanelles for the battleships was responsible
for direct hits from 15 in. guns on invisible targets at ranges of over
12,000 yards. Seaplane pilots were bombing specialists, including among
their targets army headquarters, ammunition dumps, railway stations,
submarines and their bases, docks, shipping in German harbours, and the
German Fleet at Wilhelmshaven. Dunkirk, a British seaplane base, was a
sharp thorn in the German side.
Turning from consideration of the various services to the exploits of
the men composing them, it is difficult to particularise. A certain
inevitable prejudice even at this length of time leads one to discount
the valour of pilots in the German Air Service, but the names of
Boelcke, von Richthofen, and Immelmann recur as proof of the courage
that was not wanting in the enemy ranks, while, however much we may
decry the Gotha raids over the English coast and on London, there is
no doubt that the men who undertook these raids were not deficient in
the form of bravery that is of more value than the unthinking valour
of a minute which, observed from the right quarter, wins a military
decoration.
Yet the fact that the Allied airmen kept the air at all in the early
days proved on which side personal superiority lay, for they were
outnumbered, out-manœuvred, and faced by better material than any that
they themselves possessed; yet they won their fights or died. The
stories of their deeds are endless; Bishop, flying alone and meeting
seven German machines and crashing four; the battle of May 5th, 1915,
when five heroes fought and conquered twenty-seven German machines,
ranging in altitude, between 12,000 and 3,000 feet, and continuing the
extraordinary struggle from five until six in the evening. Captain
Aizlewood, attacking five enemy machines with such reckless speed that
he rammed one and still reached his aerodrome safely--these are items
in a long list of feats of which the character can only be realised
when it is fully comprehended that the British Air Service accounted
for some 8,000 enemy machines in the course of the War. Among the
French there was Captain Guynemer, who at the time of his death had
brought down fifty-four enemy machines, in addition to many others of
which the destruction could not be officially confirmed. There was
Fonck, who brought down six machines in one day, four of them within
two minutes.
There are incredible stories, true as incredible, of shattered men
carrying on with their work in absolute disregard of physical injury.
Major Brabazon Rees, V.C., engaged a big German battleplane in
September of 1915 and, single-handed, forced his enemy out of action.
Later in his career, with a serious wound in the thigh from which
blood was pouring, he kept up a fight with an enemy formation until he
had not a round of ammunition left, and then returned to his aerodrome
to get his wound dressed. Lieutenants Otley and Dunning, flying in
the Balkans, engaged a couple of enemy machines and drove them off,
but not until their petrol tank had got a hole in it and Dunning was
dangerously wounded in the leg. Otley improvised a tourniquet, passed
it to Dunning, and, when the latter had bandaged himself, changed from
the observer’s to the pilot’s seat, plugged the bullet hole in the tank
with his thumb and steered the machine home.
These are incidents; the full list has not been, and can never be
recorded, but it goes to show that in the pilot of the War period there
came to being a new type of humanity, a product of evolution which
fitted a certain need. Of such was Captain West, who, engaging hostile
troops, was attacked by seven machines. Early in the engagement,
one of his legs was partially severed by an explosive bullet and
fell powerless into the controls, rendering the machine for the time
unmanageable. Lifting his disabled leg, he regained control of the
machine, and although wounded in the other leg, he manœuvred his
machine so skilfully that his observer was able to get several good
bursts into the enemy machines, driving them away. Then, desperately
wounded as he was, Captain West brought the machine over to his own
lines and landed safely. He fainted from loss of blood and exhaustion,
but on regaining consciousness, insisted on writing his report. Equal
to this was the exploit of Captain Barker, who, in aerial combat, was
wounded in the right and left thigh and had his left arm shattered,
subsequently bringing down an enemy machine in flames, and then
breaking through another hostile formation and reaching the British
lines.
In recalling such exploits as these, one is tempted on and on, for it
seems that the pilots rivalled each other in their devotion to duty,
this not confined to British aviators, but common practically to all
services. Sufficient instances have been given to show the nature of
the work and the character of the men who did it.
The rapid growth of aerial effort rendered it necessary in January of
1915 to organise the Royal Flying Corps into separate wings, and in
October of the same year it was constituted in Brigades. In 1916 the
Air Board was formed, mainly with the object of co-ordinating effort
and ensuring both to the R.N.A.S. and to the R.F.C. adequate supplies
of material as far as construction admitted. Under the presidency
of Lord Cowdray, the Air Board brought about certain reforms early
in 1917, and in November of that year a separate Air Ministry was
constituted, separating the Air Force from both Navy and Army, and
rendering it an independent force. On April 1st, 1918, the Royal Air
Force came into existence, and unkind critics in the Royal Flying
Corps remarked on the appropriateness of the date. At the end of the
War, the personnel of the Royal Air Force amounted to 27,906 officers,
and 263,842 other ranks. Contrast of these figures with the number
of officers and men who took the field in 1914 is indicative of the
magnitude of British aerial effort in the War period.
[Illustration: The Seaplane Carrier ‘Empress’ from the stern, showing
interior of hangar.]
XX
THE WAR PERIOD--II
There was when War broke out no realisation on the part of the British
Government of the need for encouraging the enterprise of private
builders, who carried out their work entirely at their own cost. The
importance of a supply of British-built engines was realised before
the War, it is true, and a competition was held in which a prize of
£5,000 was offered for the best British engine, but this awakening
was so late that the R.F.C. took the field without a single British
power plant. Although Germany woke up equally late to the need for
home produced aeroplane engines, the experience gained in building
engines for dirigibles sufficed for the production of aeroplane power
plants. The Mercedes filled all requirements together with the Benz and
the Maybach. There was a 225 horse-power Benz which was very popular,
as were the 100 horse-power and 170 horse-power Mercedes, the last
mentioned fitted to the Aviatik biplane of 1917. The Uberursel was a
copy of the Gnome and supplied the need for rotary engines.
In Great Britain there were a number of aeroplane constructing
firms that had managed to emerge from the lean years 1912–1913 with
sufficient manufacturing plant to give a hand in making up the
leeway of construction when War broke out. Gradually the motor-car
firms came in, turning their body-building departments to plane and
fuselage construction, which enabled them to turn out the complete
planes engined and ready for the field. The coach-building trade soon
joined in and came in handy as propeller makers; big upholstering
and furniture firms and scores of concerns that had never dreamed of
engaging in aeroplane construction were busy on supplying the R.F.C. By
1915 hundreds of different firms were building aeroplanes and parts;
by 1917 the number had increased to over 1,000, and a capital of over
a million pounds for a firm that at the outbreak of War had employed
a score or so of hands was by no means uncommon. Women and girls came
into the work, more especially in plane construction and covering and
doping, though they took their place in the engine shops and proved
successful at acetylene welding and work at the lathes. It was some
time before Britain was able to provide its own magnetos, for this key
industry had been left in the hands of the Germans up to the outbreak
of War, and the ‘Bosch’ was admittedly supreme--even now it has never
been beaten, and can only be equalled, being as near perfection as is
possible for a magneto.
One of the great inventions of the War was the synchronisation of
engine-timing and machine-gun, which rendered it possible to fire
through the blades of a propeller without damaging them, though the
growing efficiency of the aeroplane as a whole and of its armament
is a thing to marvel at on looking back and considering what was
actually accomplished. As the efficiency of the aeroplane increased,
so anti-aircraft guns and range-finding were improved. Before the War
an aeroplane travelling at full speed was reckoned perfectly safe at
4,000 feet, but, by the first month of 1915, the safe height had gone
up to 9,000 feet, 7,000 feet being the limit of rifle and machine gun
bullet trajectory; the heavier guns were not sufficiently mobile to
tackle aircraft. At that time, it was reckoned that effective aerial
photography ceased at 6,000 feet, while bomb-dropping from 7,000–8,000
feet was reckoned uncertain except in the case of a very large target.
The improvement in anti-aircraft devices went on, and by May of 1916,
an aeroplane was not safe under 15,000 feet, while anti-aircraft shells
had fuses capable of being set to over 20,000 feet, and bombing from
15,000 and 16,000 feet was common. It was not till later that Allied
pilots demonstrated the safety that lies in flying very near the
ground, this owing to the fact that, when flying swiftly at a very low
altitude, the machine is out of sight almost before it can be aimed at.
The Battle of the Somme and the clearing of the air preliminary to that
operation brought the fighting aeroplane pure and simple with them.
Formations of fighting planes preceded reconnaissance craft in order
to clear German machines and observation balloons out of the sky and
to watch and keep down any further enemy formations that might attempt
to interfere with Allied observation work. The German reply to this
consisted in the formation of the Flying Circus, of which Captain Baron
von Richthofen’s was a good example. Each circus consisted of a large
formation of speedy machines, built specially for fighting and manned
by the best of the German pilots. These were sent to attack at any
point along the line where the Allies had got a decided superiority.
The trick flying of pre-war days soon became an everyday matter;
Pegoud astonished the aviation world before the War by first looping
the loop, but, before three years of hostilities had elapsed, looping
was part of the training of practically every pilot, while the spinning
nose dive, originally considered fatal, was mastered, and the tail
slide, which consisted of a machine rising nose upward in the air and
falling back on its tail, became one of the easiest ‘stunts’ in the
pilot’s repertoire. Inherent stability was gradually improved, and,
from 1916 onward, practically every pilot could carry on with his
machine-gun or camera and trust to his machine to fly itself until he
was free to attend to it. There was more than one story of a machine
coming safely to earth and making good landing on its own account with
the pilot dead in his cock-pit.
Toward the end of the War, the Independent Air Force was formed as a
branch of the R.A.F. with a view to bombing German bases and devoting
its attention exclusively to work behind the enemy lines. Bombing
operations were undertaken by the R.N.A.S. as early as 1914–1915
against Cuxhaven, Dusseldorf, and Friedrichshavn, but the supply
of material was not sufficient to render these raids continuous. A
separate Brigade, the 8th, was formed in 1917 to harass the German
chemical and iron industries, the base being in the Nancy area, and
this policy was found so fruitful that the Independent Force was
constituted on the 8th June, 1918. The value of the work accomplished
by this force is demonstrated by the fact that the German High Command
recalled twenty fighting squadrons from the Western front to counter
its activities, and, in addition, took troops away from the fighting
line in large numbers for manning anti-aircraft batteries and
searchlights. The German press of the last year of the War is eloquent
of the damage done in manufacturing areas by the Independent Force,
which, had hostilities continued a little longer, would have included
Berlin in its activities.
Formation flying was first developed by the Germans, who made use of it
in the daylight raids against England in 1917. Its value was very soon
realised, and the V formation of wild geese was adopted, the leader
taking the point of the V and his squadron following on either side
at different heights. The air currents set up by the leading machines
were thus avoided by those in the rear, while each pilot had a good
view of the leader’s bombs, and were able to correct their own aim by
the bursts, while the different heights at which they flew rendered
anti-aircraft gun practice less effective. Further, machines were able
to afford mutual protection to each other and any attacker would be
met by machine-gun fire from three or four machines firing on him from
different angles and heights. In the later formations single-seater
fighters flew above the bombers for the purpose of driving off hostile
craft. Formation flying was not fully developed when the end of the War
brought stagnation in place of the rapid advance in the strategy and
tactics of military air work.
XXI
RECONSTRUCTION
The end of the War brought a pause in which the multitude of aircraft
constructors found themselves faced with the possible complete
stagnation of the industry, since military activities no longer
demanded their services and the prospects of commercial flying were
virtually nil. That great factor in commercial success, cost of plant
and upkeep, had received no consideration whatever in the War period,
for armies do not count cost. The types of machines that had evolved
from the War were very fast, very efficient, and very expensive,
although the bombers showed promise of adaptation to commercial needs,
and, so far as other machines were concerned, America had already
proved the possibilities of mail-carrying by maintaining a mail service
even during the War period.
A civil aviation department of the Air Ministry was formed in February
of 1919 with a Controller General of Civil Aviation at the head.
This was organised into four branches, one dealing with the survey
and preparation of air routes for the British Empire, one organising
meteorological and wireless telegraphy services, one dealing with the
licensing of aerodromes, machines for passenger or goods carrying
and civilian pilots, and one dealing with publicity and transmission
of information generally. A special Act of Parliament entitled ‘The
Air Navigation Acts, 1911–1919,’ was passed on February 27th, and
commercial flying was officially permitted from May 1st, 1919.
Meanwhile the great event of 1919, the crossing of the Atlantic by
air, was gradually ripening to performance. In addition to the rigid
airship, R.34, eight machines entered for this flight, these being a
Short seaplane, Handley-Page, Martinsyde, Vickers-Vimy, and Sopwith
aeroplanes, and three American flying boats, N.C.1, N.C.3, and N.C.4.
The Short seaplane was the only one of the eight which proposed to
make the journey westward; in flying from England to Ireland, before
starting on the long trip to Newfoundland, it fell into the sea off
the coast of Anglesey, and so far as it was concerned the attempt was
abandoned.
The first machines to start from the Western end were the three
American seaplanes, which on the morning of May 6th left Trepassy,
Newfoundland, on the 1,380 mile stage to Horta in the Azores. N.C.1
and N.C.3 gave up the attempt very early, but N.C.4, piloted by
Lieut.-Commander Read, U.S.N., made Horta on May 17th and made a three
days’ halt. On the 20th, the second stage of the journey to Ponta
Delgada, a further 190 miles, was completed and a second halt of a week
was made. On the 27th, the machine left for Lisbon, 900 miles distant,
and completed the journey in a day. On the 30th a further stage of 340
miles took N.C.4 on to Ferrol, and the next day the last stage of 420
miles to Plymouth was accomplished.
Meanwhile, H. G. Hawker, pilot of the Sopwith biplane, together with
Commander Mackenzie Grieve, R.N., his navigator, found the weather
sufficiently auspicious to set out at 6.48 p.m. on Sunday, May 18th,
in the hope of completing the trip by the direct route before N.C.4
could reach Plymouth. They set out from Mount Pearl aerodrome, St
John’s, Newfoundland, and vanished into space, being given up as lost,
as Hamel was lost immediately before the War in attempting to fly the
North Sea. There was a week of dead silence regarding their fate, but
on the following Sunday morning there was world-wide relief at the news
that the plucky attempt had not ended in disaster, but both aviators
had been picked up by the steamer _Mary_ at 9.30 a.m. on the morning of
the 19th, while still about 750 miles short of the conclusion of their
journey. Engine failure brought them down, and they planed down to the
sea close to the _Mary_ to be picked up; as the vessel was not fitted
with wireless, the news of their rescue could not be communicated until
land was reached. An equivalent of half the £10,000 prize offered by
the _Daily Mail_ for the non-stop flight was presented by the paper in
recognition of the very gallant attempt, and the King conferred the Air
Force Cross on both pilot and navigator.
Raynham, pilot of the Martinsyde competing machine, had the bad luck to
crash his craft twice in attempting to start before he got outside the
boundary of the aerodrome. The Handley-Page machine was withdrawn from
the competition, and, attempting to fly to America, was crashed on the
way.
[Illustration: The Atlantic Flight.
Front view of the Vickers-Vimy machine standing on its nose in the bog
at Clifden, Co. Galway.]
The first non-stop crossing was made on June 14th-15th in 16 hours 27
minutes, the speed being just over 117 miles per hour. The machine
was a Vickers-Vimy bomber, engined with two Rolls-Royce Eagle
VIII’s, piloted by Captain John Alcock, D.S.C., with Lieut. Arthur
Whitten-Brown as navigator. The journey was reported to be very
rough, so much so at times that Captain Alcock stated that they were
flying upside down, and for the greater part of the time they were
out of sight of the sea. Both pilot and navigator had the honour of
knighthood conferred on them at the conclusion of the journey.
Meanwhile, commercial flying opened on May 8th (the official date
was May 1st) with a joy-ride service from Hounslow of Avro training
machines. The enterprise caught on remarkably, and the company extended
their activities to coastal resorts for the holiday season--at
Blackpool alone they took up 10,000 passengers before the service was
two months old. Hendon, beginning passenger flights on the same date,
went in for exhibition and passenger flying, and on June 21st the
aerial Derby was won by Captain Gathergood on an Airco 4R machine with
a Napier 450 horse-power ‘Lion’ engine; incidentally the speed of 129.3
miles per hour was officially recognised as constituting the world’s
record for speed within a closed circuit. On July 17th a Fiat B.R.
biplane with a 700 horse-power engine landed at Kenley aerodrome after
having made a non-stop flight of 1,100 miles. The maximum speed of this
machine was 160 miles per hour, and it was claimed to be the fastest
machine in existence. On August 25th a daily service between London and
Paris was inaugurated by the Aircraft Manufacturing Company, Limited,
who ran a machine each way each day, starting at 12.30 and due to
arrive at 2.45 p.m. The Handley-Page Company began a similar service in
September of 1919, but ran it on alternate days with machines capable
of accommodating ten passengers. The single fare in each case was
fixed at 15 guineas and the parcel rate at 7s. 6d. per pound.
Meanwhile, in Germany, a number of passenger services had been in
operation from the early part of the year; the Berlin-Weimar service
was established on February 5th and Berlin-Hamburg on March 1st, both
for mail and passenger carrying. Berlin-Breslau was soon added, but
the first route opened remained most popular, 538 flights being made
between its opening and the end of April, while for March and April
combined, the Hamburg-Berlin route recorded only 262 flights. All three
routes were operated by a combine of German aeronautical firms entitled
the Deutsche Luft Rederie. The single fare between Hamburg and Berlin
was 450 marks, between Berlin and Breslau 500 marks, and between Berlin
and Weimar 450 marks. Luggage was carried free of charge, but varied
according to the weight of the passenger, since the combined weight of
both passenger and luggage was not allowed to exceed a certain limit.
In America commercial flying had begun in May of 1918 with the mail
service between Washington, Philadelphia, and New York, which proved
that mail carrying is a commercial possibility, and also demonstrated
the remarkable reliability of the modern aeroplane by making 102
complete flights out of a possible total of 104 in November, 1918, at
a cost of 0.777 of a dollar per mile. By March of 1919 the cost per
mile had gone up to 1.28 dollars; the first annual report issued at
the end of May showed an efficiency of 95.6 per cent and the original
six aeroplanes and engines with which the service began were still in
regular use.
[Illustration: The N.C. 4 and N.C. 1 lying ready to start on the
Atlantic Flight.]
In June of 1919 an American commercial firm chartered an aeroplane
for emergency service owing to a New York harbour strike and found it
so useful that they made it a regular service. The Travellers Company
inaugurated a passenger flying boat service between New York and
Atlantic City on July 25th, the fare, inclusive of 35 lbs. of luggage,
being fixed at £25 each way.
Five flights on the American continent up to the end of 1919 are worthy
of note. On December 13th, 1918, Lieut. D. Godoy of the Chilian army
left Santiago, Chili, crossed the Andes at a height of 19,700 feet
and landed at Mendoza, the capital of the wine-growing province of
Argentina. On April 19th, 1919, Captain E. F. White made the first
non-stop flight between New York and Chicago in 6 hours 50 minutes on
a D.H.4 machine driven by a twelve-cylinder Liberty engine. Early in
August Major Schroeder, piloting a French Lepere machine flying at a
height of 18,400 feet, reached a speed of 137 miles per hour with a
Liberty motor fitted with a super-charger. Toward the end of August,
Rex Marshall, on a Thomas-Morse biplane, starting from a height
of 17,000 feet, made a glide of 35 miles with his engine cut off,
restarting it when at a height of 600 feet above the ground. About a
month later R. Rohlfe, piloting a Curtiss triplane, broke the height
record by reaching 34,610 feet.
XXII
1919–20
Into the later months of 1919 comes the flight by Captain Ross-Smith
from England to Australia and the attempt to make the Cape to Cairo
voyage by air. The Australian Government had offered a prize of £10,000
for the first flight from England to Australia in a British machine,
the flight to be accomplished in 720 consecutive hours. Ross-Smith,
with his brother, Lieut. Keith Macpherson Smith, and two mechanics,
left Hounslow in a Vickers-Vimy bomber with Rolls-Royce engine on
November 12th and arrived at Port Darwin, North Australia, on the 10th
December, having completed the flight in 27 days 20 hours 20 minutes,
thus having 51 hours 40 minutes to spare out of the 720 allotted hours.
[Illustration: Australian Flight finish, 10th December, 1919.
The crew and machine.]
[Illustration: Cape to Cairo.
The ‘Silver Queen’ and its crew.]
Early in 1920 came a series of attempts at completing the journey by
air between Cairo and the Cape. Out of four competitors Colonel Van
Ryneveld came nearest to making the journey successfully, leaving
England on a standard Vickers-Vimy bomber with Rolls-Royce engines,
identical in design with the machine used by Captain Ross-Smith on the
England to Australia flight. A second Vickers-Vimy was financed by the
_Times_ newspaper and a third flight was undertaken with a Handley-Page
machine under the auspices of the _Daily Telegraph_. The Air Ministry
had already prepared the route by means of three survey parties which
cleared the aerodromes and landing grounds, dividing their journey
into stages of 200 miles or less. Not one of the competitors completed
the course, but in both this and Ross-Smith’s flight valuable data was
gained in respect of reliability of machines and engines, together with
a mass of meteorological information.
The Handley-Page Company announced in the early months of 1920 that
they had perfected a new design of wing which brought about a twenty to
forty per cent improvement in lift rate in the year. When the nature
of the design was made public, it was seen to consist of a division
of the wing into small sections, each with its separate lift. A few
days later, Fokker, the Dutch inventor, announced the construction
of a machine in which all external bracing wires are obviated, the
wings being of a very deep section and self-supporting. The value of
these two inventions remains to be seen so far as commercial flying is
concerned.
The value of air work in war, especially so far as the Colonial
campaigns in which British troops are constantly being engaged is in
question, was very thoroughly demonstrated in a report issued early in
1920 with reference to the successful termination of the Somaliland
campaign through the intervention of the Royal Air Force, which between
January 21st and the 31st practically destroyed the Dervish force under
the Mullah, which had been a thorn in the side of Britain since 1907.
Bombs and machine-guns did the work, destroying fortifications and
bringing about the surrender of all the Mullah’s following, with the
exception of about seventy who made their escape.
Certain records both in construction and performance had characterised
the post-war years, though as design advances and comes nearer to
perfection, it is obvious that records must get fewer and farther
between. The record aeroplane as regards size at the time of its
construction was the Tarrant triplane, which made its first--and
last--flight on May 28th, 1919. The total loaded weight was 30 tons,
and the machine was fitted with six 400 horse-power engines; almost
immediately after the trial flight began, the machine pitched forward
on its nose and was wrecked, causing fatal injuries to Captains Dunn
and Rawlings, who were aboard the machine. A second accident of similar
character was that which befell the giant seaplane known as the
Felixstowe Fury, in a trial flight. This latter machine was intended to
be flown to Australia, but was crashed over the water.
On May 4th, 1920, a British record for flight duration and useful load
was established by a commercial type Handley-Page biplane, which,
carrying a load of 3,690 lbs., rose to a height of 13,999 feet and
remained in the air for 1 hour 20 minutes. On May 27th the French
pilot, Fronval, flying at Villacoublay in a Morane-Saulnier type of
biplane with Le Rhone motor, put up an extraordinary type of record by
looping the loop 962 times in 3 hours 52 minutes 10 seconds. Another
record of the year of similar nature was that of two French fliers,
Boussotrot and Bernard, who achieved a continuous flight of 24 hours 19
minutes 7 seconds, beating the pre-war record of 21 hours 48¾ seconds
set up by the German pilot, Landemann. Both these records are likely to
stand, being in the nature of freaks, which demonstrate little beyond
the reliability of the machine and the capacity for endurance on the
part of its pilots.
[Illustration: Trial Flight of the Tarrant Triplane at Farnborough.
The machine before the crash.]
Meanwhile, on February 14th, Lieuts. Masiero and Ferrarin left Rome
on S.V.A. Ansaldo V. machines fitted with 220 horse-power S.V.A.
motors. On May 30th they arrived at Tokio, having flown by way of
Bagdad, Karachi, Canton, Pekin, and Osaka. Several other competitors
started, two of whom were shot down by Arabs in Mesopotamia.
Considered in a general way, the first two years after the termination
of the Great European War form a period of transition in which the
commercial type of aeroplane was gradually evolved from the fighting
machine which was perfected in the four preceding years. There was
about this period no sense of finality, but it was as experimental, in
its own way, as were the years of progressing design which preceded
the war period. Such commercial schemes as were inaugurated call for
no more note than has been given here; they have been experimental,
and, with the possible exception of the United States Government mail
service, have not been planned and executed on a sufficiently large
scale to furnish reliable data on which to forecast the prospects of
commercial aviation. And there is a school rapidly growing up which
asserts that the day of aeroplanes is nearly over. The construction of
the giant airships of to-day and the successful return flight of R34
across the Atlantic seem to point to the eventual triumph, in spite of
its disadvantages, of the dirigible airship.
This is a hard saying for such of the aeroplane industry as survived
the War period and consolidated itself, and it is but the saying of
a section which bases its belief on the fact that, as was noted in
the very early years of the century, the aeroplane is primarily a
war machine. Moreover, the experience of the War period tended to
discredit the dirigible, since, before the introduction of helium gas,
the inflammability of its buoyant factor placed it at an immense
disadvantage beside the machine dependent on the atmosphere itself for
its lift.
As life runs to-day, it is a long time since Kipling wrote his story
of the airways of a future world and thrust out a prophecy that the
bulk of the world’s air traffic would be carried by gas-bag vessels. If
the school which inclines to belief in the dirigible is right in its
belief, as it well may be, then the foresight was uncannily correct,
not only in the matter of the main assumption, but in the detail with
which the writer embroidered it.
On the constructional side, the history of the aeroplane is still so
much in the making that any attempt at a critical history would be
unwise, and it is possible only to record fact, leaving it to the
future for judgment to be passed. But, in a general way, criticism
may be advanced with regard to the place that aeronautics takes
in civilisation. In the past hundred years, the world has made
miraculously rapid strides materially, but moral development has not
kept abreast. Conception of the responsibilities of humanity remains
virtually in a position of a hundred years ago; given a higher
conception of life and its responsibilities, the aeroplane becomes the
crowning achievement of that long series which James Watt inaugurated,
the last step in inter-communication, the chain with which all nations
are bound in a growing prosperity, surely based on moral wellbeing.
Without such conception of the duties as well as the rights of life,
this last achievement of science may yet prove the weapon that shall
end civilisation as men know it to-day, and bring this ultra-material
age to a phase of ruin on which saner people can build a world more
reasonable and less given to groping after purely material advancement.
[Illustration: The Tarrant smash.
Front view of crashed machine. Searching for the injured after the
smash.]
PART II
1903–1920: PROGRESS IN DESIGN
BY
LIEUT-COL. W. LOCKWOOD MARSH
I
THE BEGINNINGS
Although the first actual flight of an aeroplane was made by the
Wrights on December 17th, 1903, it is necessary, in considering the
progress of design between that period and the present day, to go back
to the earlier days of their experiments with ‘gliders,’ which show the
alterations in design made by them in their step-by-step progress to a
flying machine proper, and give a clear idea of the stage at which they
had arrived in the art of aeroplane design at the time of their first
flights.
They started by carefully surveying the work of previous experimenters,
such as Lilienthal and Chanute, and from the lesson of some of the
failures of these pioneers evolved certain new principles which were
embodied in their first glider, built in 1900. In the first place,
instead of relying upon the shifting of the operator’s body to obtain
balance, which had proved too slow to be reliable, they fitted in
front of the main supporting surfaces what we now call an ‘elevator,’
which could be flexed, to control the longitudinal balance, from where
the operator lay prone upon the main supporting surfaces. The second
main innovation which they incorporated in this first glider, and the
principle of which is still used in every aeroplane in existence, was
the attainment of lateral balance by warping the extremities of the
main planes. The effect of warping or pulling down the extremity
of the wing on one side was to increase its lift and so cause that
side to rise. In the first two gliders this control was also used
for steering to right and left. Both these methods of control were
novel for other than model work, as previous experimenters, such as
Lilienthal and Pilcher, had relied entirely upon moving the legs or
shifting the position of the body to control the longitudinal and
lateral motions of their gliders. For the main supporting surfaces of
the glider the biplane system of Chanute’s gliders was adopted with
certain modifications, while the curve of the wings was founded upon
the calculations of Lilienthal as to wind pressure and consequent lift
of the plane.
This first glider was tested on the Kill Devil Hill sandhills in North
Carolina in the summer of 1900, and proved at any rate the correctness
of the principles of the front elevator and warping wings, though
its designers were puzzled by the fact that the lift was less than
they expected; whilst the ‘drag’ (as we call it), or resistance, was
also considerably lower than their predictions. The 1901 machine was,
in consequence, nearly doubled in area--the lifting surface being
increased from 165 to 308 square feet--the first trial taking place
on July 27th, 1901, again at Kill Devil Hill. It immediately appeared
that something was wrong, as the machine dived straight to the ground,
and it was only after the operator’s position had been moved nearly a
foot back from what had been calculated as the correct position that
the machine would glide--and even then the elevator had to be used far
more strongly than in the previous year’s glider. After a good deal of
thought the apparent solution of the trouble was finally found. This
consisted in the fact that with curved surfaces, while at large angles
the centre of pressure moves forward as the angle decreases, when a
certain limit of angle is reached it travels suddenly backwards and
causes the machine to dive. The Wrights had known of this tendency from
Lilienthal’s researches, but had imagined that the phenomenon would
disappear if they used a fairly lightly cambered--or curved--surface
with a very abrupt curve at the front. Having discovered what appeared
to be the cause they surmounted the difficulty by ‘trussing down’ the
camber of the wings, with the result that they at once got back to
the old conditions of the previous year and could control the machine
readily with small movements of the elevator, even being able to follow
undulations in the ground. They still found, however, that the lift was
not as great as it should have been; while the drag remained, as in
the previous glider, surprisingly small. This threw doubt on previous
figures as to wind resistance and pressure on curved surfaces; but
at the same time confirmed (and this was a most important result)
Lilienthal’s previously questioned theory that at small angles the
pressure on a curved surface instead of being normal, or at right
angles to, the chord is in fact inclined in front of the perpendicular.
The result of this is that the pressure actually tends to draw the
machine forward into the wind--hence the small amount of drag, which
had puzzled Wilbur and Orville Wright.
Another lesson which was learnt from these first two years of
experiment, was that where, as in a biplane, two surfaces are
superposed one above the other, each of them has somewhat less lift
than it would have if used alone. The experimenters were also still
in doubt as to the efficiency of the warping method of controlling
the lateral balance as it gave rise to certain phenomena which
puzzled them, the machine turning towards the wing having the greater
angle, which seemed also to touch the ground first, contrary to their
expectations. Accordingly, on returning to Dayton towards the end of
1901, they set themselves to solve the various problems which had
appeared and started on a lengthy series of experiments to check the
previous figures as to wind resistance and lift of curved surfaces,
besides setting themselves to grapple with the difficulty of lateral
control. They accordingly constructed for themselves at their home
in Dayton a wind tunnel 16 inches square by 6 feet long in which
they measured the lift and ‘drag’ of more than two hundred miniature
wings. In the course of these tests they for the first time produced
comparative results of the lift of oblong and square surfaces,
with the result that they re-discovered the importance of ‘aspect
ratio’--the ratio of length to breadth of planes. As a result, in the
next year’s glider the aspect ration of the wings was increased from
the three to one of the earliest model to about six to one, which
is approximately the same as that used in the machines of to-day.
Further than that, they discussed the question of lateral stability,
and came to the conclusion that the cause of the trouble was that the
effect of warping down one wing was to increase the resistance of,
and consequently slow down, that wing to such an extent that its lift
was reduced sufficiently to wipe out the anticipated increase in lift
resulting from the warping. From this they deduced that if the speed
of the warped wing could be controlled the advantage of increasing
the angle by warping could be utilised as they originally intended.
They therefore decided to fit a vertical fin at the rear which, if the
machine attempted to turn, would be exposed more and more to the wind
and so stop the turning motion by offering increased resistance.
As a result of this laboratory research work the third Wright glider,
which was taken to Kill Devil Hill in September, 1902, was far more
efficient aerodynamically than either of its two predecessors, and
was fitted with a fixed vertical fin at the rear in addition to the
movable elevator in front. According to Mr Griffith Brewer,[8] this
third glider contained 305 square feet of surface; though there may
possibly be a mistake here, as he states[9] the surface of the previous
year’s glider to have been only 290 square feet, whereas Wilbur Wright
himself[10] states it to have been 308 square feet. The matter is not,
perhaps, save historically, of much importance, except that the gliders
are believed to have been progressively larger, and therefore if we
accept Wilbur Wright’s own figure of the surface of the second glider,
the third must have had a greater area than that given by Mr Griffith
Brewer. Unfortunately, no evidence of the Wright Brothers themselves on
this point is available.
The first glide of the 1902 season was made on September 17th of that
year, and the new machine at once showed itself an improvement on its
predecessors, though subsequent trials showed that the difficulty
of lateral balance had not been entirely overcome. It was decided,
therefore, to turn the vertical fin at the rear into a rudder by
making it movable. At the same time it was realised that there was a
definite relation between lateral balance and directional control, and
the rudder controls and wing-warping wires were accordingly connected.
This ended the pioneer gliding experiments of Wilbur and Orville
Wright--though further glides were made in subsequent years--as the
following year, 1903, saw the first power-driven machine leave the
ground.
To recapitulate--in the course of these original experiments the
Wrights confirmed Lilienthal’s theory of the reversal of the centre
of pressure on cambered surfaces at small angles of incidence: they
confirmed the importance of high aspect ratio in respect to lift:
they had evolved new and more accurate tables of lift and pressure on
cambered surfaces: they were the first to use a movable horizontal
elevator for controlling height: they were the first to adjust the
wings to different angles of incidence to maintain lateral balance: and
they were the first to use the movable rudder and adjustable wings in
combination.
They now considered that they had gone far enough to justify them in
building a power-driven ‘flier,’ as they called their first aeroplane.
They could find no suitable engine and so proceeded to build for
themselves an internal combustion engine, which was designed to give
8 horse-power, but when completed actually developed about 12–15
horse-power and weighed 240 lbs. The complete machine weighed about 750
lbs. Further details of the first Wright aeroplane are difficult to
obtain, and even those here given should be received with some caution.
The first flight was made on December 17th, 1903, and lasted 12
seconds. Others followed immediately, and the fourth lasted 59 seconds,
a distance of 852 feet being covered against a 20-mile wind.
The following year they transferred operations to a field outside
Dayton, Ohio (their home), and there they flew a somewhat larger and
heavier machine with which on September 20th, 1904, they completed the
first circle in the air. In this machine for the first time the pilot
had a seat; all the previous experiments having been carried out with
the operator lying prone on the lower wing. This was followed next
year by another still larger machine, and on it they carried out many
flights. During the course of these flights they satisfied themselves
as to the cause of a phenomenon which had puzzled them during the
previous year and caused them to fear that they had not solved the
problem of lateral control. They found that on occasions--always when
on a turn--the machine began to slide down towards the ground and
that no amount of warping could stop it. Finally it was found that if
the nose of the machine was tilted down a recovery could be effected;
from which they concluded that what actually happened was that the
machine, ‘owing to the increased load caused by centrifugal force,’
had insufficient power to maintain itself in the air and therefore
lost speed until a point was reached at which the controls became
inoperative. In other words, this was the first experience of ‘stalling
on a turn,’ which is a danger against which all embryo pilots have to
guard in the early stages of their training.
The 1905 machine was, like its predecessors, a biplane with a biplane
elevator in front and a double vertical rudder in rear. The span was
40 feet, the chord of the wings being 6 feet and the gap between
them about the same. The total area was about 600 square feet which
supported a total weight of 925 lbs.; while the motor was 12 to 15
horse-power driving two propellers on each side behind the main planes
through chains and giving the machine a speed of about 30 m.p.h. One of
these chains was crossed so that the propellers revolved in opposite
directions to avoid the torque which it was feared would be set up if
they both revolved the same way. The machine was not fitted with a
wheeled undercarriage but was carried on two skids, which also acted as
outriggers to carry the elevator. Consequently, a mechanical method of
launching had to be evolved and the machine received initial velocity
from a rail, along which it was drawn by the impetus provided by the
falling of a weight from a wooden tower or ‘pylon.’ As a result of this
the Wright aeroplane in its original form had to be taken back to its
starting rail after each flight, and could not restart from the point
of alighting. Perhaps, in comparison with French machines of more or
less contemporary date (evolved on independent lines in ignorance of
the Americans’ work), the chief feature of the Wright biplane of 1905
was that it relied entirely upon the skill of the operator for its
stability; whereas in France some attempt was being made, although
perhaps not very successfully, to make the machine automatically stable
laterally. The performance of the Wrights in carrying a loading of some
60 lbs. per horse-power is one which should not be overlooked. The wing
loading was about 1½ lbs. per square foot.
About the same time that the Wrights were carrying out their
power-driven experiments, a band of pioneers was quite independently
beginning to approach success in France. In practically every case,
however, they started from a somewhat different standpoint and took
as their basic idea the cellular (or box) kite. This form of kite,
consisting of two superposed surfaces connected at each end by a
vertical panel or curtain of fabric, had proved extremely successful
for man-carrying purposes, and, therefore, it was little wonder that
several minds conceived the idea of attempting to fly by fitting a
series of box-kites with an engine. The first to achieve success was M.
Santos-Dumont, the famous Brazilian pioneer-designer of airships, who,
on November 12th, 1906, made several flights, the last of which covered
a little over 700 feet. Santos-Dumont’s machine consisted essentially
of two box-kites, forming the main wings, one on each side of the body,
in which the pilot stood, and at the front extremity of which was
another movable box-kite to act as elevator and rudder. The curtains
at the ends were intended to give lateral stability, which was further
ensured by setting the wings slightly inclined upwards from the centre,
so that when seen from the front they formed a wide V. This feature is
still to be found in many aeroplanes to-day and has come to be known
as the ‘dihedral.’ The motor was at first of 24 horse-power, for which
later a 50 horse-power Antoinette engine was substituted; whilst a
three-wheeled undercarriage was provided, so that the machine could
start without external mechanical aid. The machine was constructed of
bamboo and steel, the weight being as low as 352 lbs. The span was 40
feet, the length being 33 feet, with a total surface of main planes of
860 square feet. It will thus be seen--for comparison with the Wright
machine--that the weight per horse-power (with the 50 horse-power
engine) was only 7 lbs., while the wing loading was equally low at ½
lb. per square foot.
The main features of the Santos-Dumont machine were the box-kite form
of construction, with a dihedral angle on the main planes, and the
forward elevator which could be moved in any direction and therefore
acted in the same way as the rudder at the rear of the Wright biplane.
It had a single propeller revolving in the centre behind the wings and
was fitted with an undercarriage incorporated in the machine.
The other chief French experimenters at this period were the Voisin
Frères, whose first two machines--identical in form--were sold to
Delagrange and H. Farman, which has sometimes caused confusion, the two
purchasers being credited with the design they bought. The Voisins,
like the Wrights, based their designs largely on the experimental work
of Lilienthal, Langley, Chanute, and others, though they also carried
out tests on the lifting properties of aerofoils in a wind tunnel of
their own. Their first machines, like those of Santos-Dumont, showed
the effects of experimenting with box-kites, some of which they had
built for M. Ernest Archdeacon in 1904. In their case the machine,
which was again a biplane, had, like both the others previously
mentioned, an elevator in front--though in this case of monoplane
form--and, as in the Wright, a rudder was fitted in rear of the main
planes. The Voisins, however, fitted a fixed biplane horizontal
‘tail’--in an effort to obtain a measure of automatic longitudinal
stability--between the two surfaces of which the single rudder worked.
For lateral stability they depended entirely on end curtains between
the upper and lower surfaces of both the main planes and biplane tail
surfaces. They, like Santos-Dumont, fitted a wheeled undercarriage,
so that the machine was self-contained. The Voisin machine, then,
was intended to be automatically stable in both senses; whereas the
Wrights deliberately produced a machine which was entirely dependent
upon the pilot’s skill for its stability. The dimensions of the Voisin
may be given for comparative purposes, and were as follows: Span 33
feet with a chord (width from back to front) of main planes of 6½ feet,
giving a total area of 430 square feet. The 50 horse-power Antoinette
engine, which was enclosed in the body (or ‘nacelle’) in the front of
which the pilot sat, drove a propeller behind, revolving between the
outriggers carrying the tail. The total weight, including Farman as
pilot, is given as 1,540 lbs., so that the machine was much heavier
than either of the others; the weight per horse-power being midway
between the Santos-Dumont and the Wright at 31 lbs. per square foot,
while the wing loading was considerably greater than either at 3½ lbs.
per square foot. The Voisin machine was experimented with by Farman
and Delagrange from about June 1907 onwards, and was in the subsequent
years developed by Farman; and right up to the commencement of the
War upheld the principles of the box-kite method of construction for
training purposes. The chief modification of the original design was
the addition of flaps (or ailerons) at the rear extremities of the
main planes to give lateral control, in a manner analogous to the
wing-warping method invented by the Wrights, as a result of which the
end curtains between the planes were abolished. An additional elevator
was fitted at the rear of the fixed biplane tail, which eventually
led to the discarding of the front elevator altogether. During the
same period the Wright machine came into line with the others by the
fitting of a wheeled undercarriage integral with the machine. A fixed
horizontal tail was also added to the rear rudder, to which a movable
elevator was later attached; and, finally, the front elevator was done
away with. It will thus be seen that having started from the very
different standpoints of automatic stability and complete control by
the pilot, the Voisin (as developed in the Farman) and Wright machines,
through gradual evolution finally resulted in aeroplanes of similar
characteristics embodying a modicum of both features.
Before proceeding to the next stage of progress mention should be made
of the experimental work of Captain Ferber in France. This officer
carried out a large number of experiments with gliders contemporarily
with the Wrights, adopting--like them--the Chanute biplane principle.
He adopted the front elevator from the Wrights, but immediately went a
step farther by also fitting a fixed tail in rear, which did not become
a feature of the Wright machine until some seven or eight years later.
He built and appeared to have flown a machine fitted with a motor in
1905, and was commissioned to go to America by the French War Office
on a secret mission to the Wrights. Unfortunately, no complete account
of his experiments appears to exist, though it can be said that his
work was at least as important as that of any of the other pioneers
mentioned.
II
MULTIPLICITY OF IDEAS
In a review of progress such as this, it is obviously impossible,
when a certain stage of development has been reached, owing to the
very multiplicity of experimenters, to continue dealing in anything
approaching detail with all the different types of machines; and it is
proposed, therefore, from this point to deal only with tendencies, and
to mention individuals merely as examples of a class of thought rather
than as personalities, as it is often difficult fairly to allocate the
responsibility for any particular innovation.
During 1907 and 1908 a new type of machine, in the monoplane, began to
appear from the workshops of Louis Blériot, Robert Esnault-Pelterie,
and others, which was destined to give rise to long and bitter
controversies on the relative advantages of the two types, into which
it is not proposed to enter here; though the rumblings of the conflict
are still to be heard by discerning ears. Blériot’s early monoplanes
had certain new features, such as the location of the pilot, and in
some cases the engine, below the wing; but in general his monoplanes,
particularly the famous No. XI on which the first Channel crossing was
made on July 25th, 1909, embodied the main principles of the Wright
and Voisin types, except that the propeller was in front of instead
of behind the supporting surfaces, and was, therefore, what is called
a ‘tractor’ in place of the then more conventional ‘pusher.’ Blériot
aimed at lateral balance by having the tip of each wing pivoted,
though he soon fell into line with the Wrights and adopted the warping
system. The main features of the design of Esnault-Pelterie’s monoplane
was the inverted dihedral (or kathedral as this was called in Mr S. F.
Cody’s British Army Biplane of 1907) on the wings, whereby the tips
were considerably lower than the roots at the body. This was designed
to give automatic lateral stability, but, here again, conventional
practice was soon adopted and the R.E.P. monoplanes, which became
well-known in this country through their adoption in the early days
by Messrs Vickers, were of the ordinary monoplane design, consisting
of a tractor propeller with wire-stayed wings, the pilot being in an
enclosed fuselage containing the engine in front and carrying at its
rear extremity fixed horizontal and vertical surfaces combined with
movable elevators and rudder. Constructionally, the R.E.P. monoplane
was of extreme interest as the body was constructed of steel. The
Antoinette monoplane, so ably flown by Latham, was another very famous
machine of the 1909–1910 period, though its performance were frequently
marred by engine failure; which was indeed the bugbear of all these
early experimenters, and it is difficult to say, after this lapse
of time, how far in many cases the failures which occurred, both in
performances and even in the actual ability to rise from the ground,
were due to defects in design or merely faults in the primitive engines
available. The Antoinette aroused admiration chiefly through its
graceful, bird-like lines, which have probably never been equalled;
but its chief interest for our present purpose lies in the novel
method of wing-staying which was employed. Contemporary monoplanes
practically all had their wings stayed by wires to a post in the
centre above the fuselage, and, usually, to the undercarriage below. In
the Antoinette, however, a king post was introduced half-way along the
wing, from which wires were carried to the ends of the wings and the
body. This was intended to give increased strength and permitted of a
greater wing-spread and consequently improved aspect ratio. The same
system of construction was adopted in the British Martinsyde monoplanes
of two or three years later.
[Illustration: Latham’s Antoinette 29.]
This period also saw the production of the first triplane, which was
built by A. V. Roe in England and was fitted with a J.A.P. engine of
only 9 horse-power--an amazing performance which remains to this day
unequalled. Mr Roe’s triplane was chiefly interesting otherwise for
the method of maintaining longitudinal control, which was achieved
by pivoting the whole of the three main planes so that their angle
of incidence could be altered. This was the direct converse of the
universal practice of elevating by means of a subsidiary surface either
in front or rear of the main planes.
Recollection of the various flying meetings and exhibitions which
one attended during the years from 1909 to 1911, or even 1912, are
chiefly notable for the fact that the first thought on seeing any new
type of machine was not as to what its ‘performance’--in speed, lift,
or what not--would be; but speculation as to whether it would leave
the ground at all when eventually tried. This is perhaps the best
indication of the outstanding characteristic of that interim period
between the time of the first actual flights and the later period,
commencing about 1912, when ideas had become settled and it was at last
becoming possible to forecast on the drawing-board the performance of
the completed machine in the air. Without going into details, for
which there is no space here, it is difficult to convey the correct
impression of the chaotic state which existed as to even the elementary
principles of aeroplane design. All the exhibitions contained large
numbers--one had almost written a majority--of machines which embodied
the most unusual features and which never could, and in practice
never did, leave the ground. At the same time, there were few who
were sufficiently hardy to say certainly that this or that innovation
was wrong; and consequently dozens of inventors in every country were
conducting isolated experiments on both good and bad lines. All kinds
of devices, mechanical and otherwise, were claimed as the solution of
the problem of stability, and there was even controversy as to whether
any measure of stability was not undesirable; one school maintaining
that the only safety lay in the pilot having the sole say in the
attitude of the machine at any given moment, and fearing danger from
the machine having any mind of its own, so to speak. There was, as
in most controversies, some right on both sides, and when we come to
consider the more settled period from 1912 to the outbreak of the War
in 1914 we shall find how a compromise was gradually effected.
At the same time, however, though it was at the time difficult to pick
out, there was very real progress being made, and, though a number of
‘freak’ machines fell out by the wayside, the pioneer designers of
those days learnt by a process of trial and error the right principles
to follow and gradually succeeded in getting their ideas crystallised.
In connection with stability mention must be made of a machine which
was evolved in the utmost secrecy by Mr J. W. Dunne in a remote part
of Scotland under subsidy from the War Office. This type, which was
constructed in both monoplane and biplane form, showed that it was
in fact possible in 1910 and 1911 to design an aeroplane which could
definitely be left to fly itself in the air. One of the Dunne machines
was, for example, flown from Farnborough to Salisbury Plain without any
control other than the rudder being touched; and on another occasion
it flew a complete circle with all controls locked, automatically
assuming the correct bank for the radius of turn. The peculiar form
of wing used, the camber of which varied from the root to the tip,
gave rise, however, to a certain loss in efficiency, and there was
also a difficulty in the pilot assuming adequate control when desired.
Other machines designed to be stable--such as the German Etrich and
the British Weiss gliders and Handley-Page monoplanes--were based on
the analogy of a wing attached to a certain seed found in Nature (the
‘Zanonia’ leaf), on the righting effect of back-sloped wings combined
with upturned (or ‘negative’) tips. Generally speaking, however, the
machines of the 1909–1912 period relied for what automatic stability
they had on the principle of the dihedral angle, or flat V, both
longitudinally and laterally. Longitudinally this was obtained by
setting the tail at a slightly smaller angle than the main planes.
The question of reducing the resistance by adopting ‘stream-line’
forms, along which the air could flow uninterruptedly without the
formation of eddies, was not at first properly realised, though credit
should be given to Edouard Nieuport, who in 1909 produced a monoplane
with a very large body which almost completely enclosed the pilot and
made the machine very fast, for those days, with low horse-power. On
one of these machines C. T. Weymann won the Gordon-Bennett Cup for
America in 1911, and another put up a fine performance in the same
race with only a 30 horse-power engine. The subject, was however,
early taken up by the British Advisory Committee for Aeronautics,
which was established by the Government in 1909, and designers began
to realise the importance of streamline struts and fuselages towards
the end of this transition period. These efforts were at first not
always successful and showed at times a lack of understanding of the
problems involved, but there was a very marked improvement during the
year 1912. At the Paris Aero Salon held early in that year there was
a notable variety of ideas on the subject; whereas by the time of the
one held in October designs had considerably settled down, more than
one exhibitor showing what were called ‘monocoque’ fuselages completely
circular in shape and having very low resistance, while the same show
saw the introduction of rotating cowls over the propeller bosses, or
‘spinners,’ as they came to be called during the War. A particularly
fine example of stream-lining was to be found in the Deperdussin
monoplane on which Védrines won back the Gordon-Bennett Aviation Cup
from America at a speed of 105·5 m.p.h.--a considerable improvement on
the 78 m.p.h. of the preceding year, which was by no means accounted
for by the mere increase in engine power from 100 horse-power to 140
horse-power. This machine was the first in which the refinement of
‘stream-lining’ the pilot’s head, which became a feature of subsequent
racing machines, was introduced. This consisted of a circular padded
excresence above the cockpit immediately behind the pilot’s head,
which gradually tapered off into the top surface of the fuselage. The
object was to give the air an uninterrupted flow instead of allowing
it to be broken up into eddies behind the head of the pilot, and it
also provided a support against the enormous wind-pressure encountered.
This true stream-line form of fuselage owed its introduction to the
Paulhan-Tatin ‘Torpille’ monoplane of the Paris Salon of early 1912.
Altogether the end of the year 1912 began to see the disappearance of
‘freak’ machines with all sorts of original ideas for the increase
of stability and performance. Designs had by then gradually become
to a considerable extent standardised, and it had become unusual to
find a machine built which would fail to fly. The Gnome engine held
the field owing to its advantages, as the first of the rotary type,
in lightness and ease of fitting into the nose of a fuselage. The
majority of machines were tractors (propeller in front) although a
preference, which died down subsequently, was still shown for the
monoplane over the biplane. This year also saw a great increase in the
number of seaplanes, although the ‘flying boat’ type had only appeared
at intervals and the vast majority were of the ordinary aeroplane type
fitted with floats in place of the land undercarriage; which type was
at that time commonly called ‘hydro-aeroplane.’ The usual horse-power
was 50--that of the smallest Gnome engine--although engines of 100
to 140 horse-power were also fitted occasionally. The average weight
per horse-power varied from 18 to 25 lbs., while the wing-loading
was usually in the neighbourhood of 5 to 6 lbs. per square foot. The
average speed ranged from 65–75 miles per hour.
[Illustration: Bristol Fighter, rear view.]
III
PROGRESS ON STANDARDISED LINES
In the last section an attempt has been made to show how, during what
was from the design standpoint perhaps the most critical period, order
gradually became evident out of chaos, ill-considered ideas dropped out
through failure to make good, and, though there was still plenty of
room for improvement in details, the bulk of the aeroplanes showed a
general similarity in form and conception. There was still a great deal
to be learnt in finding the best form of wing section, and performances
were still low; but it had become definitely possible to say that
flying had emerged from the chrysalis stage and had become a science.
The period which now began was one of scientific development and
improvement--in performance, manœuvrability, and general airworthiness
and stability.
The British Military Aeroplane Competition held in the summer of 1912
had done much to show the requirements in design by giving possibly
the first opportunity for a definite comparison of the performance
of different machines as measured by impartial observers on standard
lines--albeit the methods of measuring were crude. These showed that
a high speed--for those days--of 75 miles an hour or so was attended
by disadvantages in the form of an equally fast low speed, of 50 miles
per hour or more, and generally may be said to have given designers an
idea what to aim for and in what direction improvements were required.
In fact, the most noticeable point perhaps of the machines of this
time was the marked manner in which a machine that was good in one
respect would be found to be wanting in others. It had not yet been
possible to combine several desirable attributes in one machine. The
nearest approach to this was perhaps to be found in the much discussed
Government B.E.2 machine, which was produced from the Royal Aircraft
Factory at Farnborough, in the summer of 1912. Though considerably
criticised from many points of view it was perhaps the nearest approach
to a machine of all-round efficiency that had up to that date appeared.
The climbing rate, which subsequently proved so important for military
purposes, was still low, seldom, if ever, exceeding 400 feet per
minute; while gliding angles (ratio of descent to forward travel over
the ground with engine stopped) little exceeded 1 in 8.
The year 1912 and 1913 saw the subsequently all-conquering tractor
biplane begin to come into its own. This type, which probably
originated in England, and at any rate attained to its greatest
excellence prior to the War from the drawing offices of the Avro
Bristol and Sopwith firms, dealt a blow at the monoplane from which the
latter never recovered.
The two-seater tractor biplane produced by Sopwith and piloted by H. G.
Hawker, showed that it was possible to produce a biplane with at least
equal speed to the best monoplanes, whilst having the advantage of
greater strength and lower landing speeds. The Sopwith machine had a
top speed of over 80 miles an hour while landing as slowly as little
more than 30 miles an hour; and also proved that it was possible
to carry 3 passengers with fuel for 4 hours’ flight with a motive
power of only 80 horse-power. This increase in efficiency was due to
careful attention to detail in every part, improved wing sections,
clean fuselage-lines, and simplified undercarriages. At the same
time, in the early part of 1913 a tendency manifested itself towards
the four-wheeled undercarriage, a pair of smaller wheels being added
in front of the main wheels to prevent overturning while running on
the ground; and several designs of oleo-pneumatic and steel-spring
undercarriages were produced in place of the rubber shock-absorber type
which had up till then been almost universal.
These two statements as to undercarriage designs may appear to be
contradictory, but in reality they do not conflict as they both showed
a greater attention to the importance of good springing, combined with
a desire to avoid complication and a mass of struts and wires which
increased head resistance.
The Olympia Aero Show of March, 1913, also produced a machine which,
although the type was not destined to prove the best for the purpose
for which it was designed, was of interest as being the first to be
designed specially for war purposes. This was the Vickers ‘Gun-bus,’ a
‘pusher’ machine, with the propeller revolving behind the main planes
between the outriggers carrying the tail, with a seat right in front
for a gunner who was provided with a machine gun on a swivelling mount
which had a free field of fire in every direction forward. The device
which proved the death-blow for this type of aircraft during the war
will be dealt with in the appropriate place later, but the machine
should not go unrecorded.
As a result of a number of accidents to monoplanes the Government
appointed a Committee at the end of 1912 to inquire into the causes
of these. The report, which was presented in March, 1913, exonerated
the monoplane by coming to the conclusion that the accidents were not
caused by conditions peculiar to monoplanes, but pointed out certain
desiderata in aeroplane design generally which are worth recording.
They recommended that the wings of aeroplanes should be so internally
braced as to have sufficient strength in themselves not to collapse
if the external bracing wires should give way. The practice, more
common in monoplanes than biplanes, of carrying important bracing
wires from the wings to the undercarriage was condemned owing to the
liability of damage from frequent landings. They also pointed out the
desirability of duplicating all main wires and their attachments, and
of using stranded cable for control wires. Owing to the suspicion
that one accident at least had been caused through the tearing of the
fabric away from the wing, it was recommended that fabric should be
more securely fastened to the ribs of the wings, and that devices for
preventing the spreading of tears should be considered. In the last
connection it is interesting to note that the French Deperdussin firm
produced a fabric wing-covering with extra strong threads run at right
angles through the fabric at intervals in order to limit the tearing to
a defined area.
In spite, however, of the whitewashing of the monoplane by the
Government Committee just mentioned, considerable stir was occasioned
later in the year by the decision of the War Office not to order any
more monoplanes; and from this time forward until the War period the
British Army was provided exclusively with biplanes. Even prior to
this the popularity of the monoplane had begun to wane. At the Olympia
Aero Show in March, 1913, biplanes for the first time outnumbered the
‘single-deckers’ (as the Germans call monoplanes); which had the effect
of reducing the wing-loading. In the case of the biplanes exhibited
this averaged about 4½ lbs. per square foot, while in the case of the
monoplanes in the same exhibition the lowest was 5½ lbs., and the
highest over 8½ lbs. per square foot of area. It may here be mentioned
that it was not until the War period that the importance of loading
per horse-power was recognised as the true criterion of aeroplane
efficiency, far greater interest being displayed in the amount of
weight borne per unit area of wing.
An idea of the state of development arrived at about this time may be
gained from the fact that the Commandant of the Military Wing of the
Royal Flying Corps in a lecture before the Royal Aeronautical Society
read in February, 1913, asked for single-seater scout aeroplanes
with a speed of 90 miles an hour and a landing speed of 45 miles
an hour--a performance which even two years later would have been
considered modest in the extreme. It serves to show that, although
higher performances were put up by individual machines on occasion,
the general development had not yet reached the stage when such
performances could be obtained in machines suitable for military
purposes. So far as seaplanes were concerned, up to the beginning of
1913 little attempt had been made to study the novel problems involved,
and the bulk of the machines at the Monaco Meeting in April, 1913,
for instance, consisted of land machines fitted with floats, in many
cases of a most primitive nature, without other alterations. Most of
those which succeeded in leaving the water did so through sheer pull
of engine power; while practically all were incapable of getting off
except in a fair sea, which enabled the pilot to jump the machine into
the air across the trough between two waves. Stability problems had not
yet been considered, and in only one or two cases was fin area added
at the rear high up, to counterbalance the effect of the floats low
down in front. Both twin and single-float machines were used, while
the flying boat was only just beginning to come into being from the
workshops of Sopwith in Great Britain, Borel-Denhaut in France, and
Curtiss in America. In view of the approaching importance of amphibious
seaplanes, mention should be made of the flying boat (or ‘bat boat’ as
it was called, following Rudyard Kipling) which was built by Sopwith in
1913 with a wheeled landing-carriage which could be wound up above the
bottom surface of the boat so as to be out of the way when alighting on
water.
During 1913 the (at one time almost universal) practice originated by
the Wright Brothers, of warping the wings for lateral stability, began
to die out and the bulk of aeroplanes began to be fitted with flaps
(or ‘ailerons’) instead. This was a distinct change for the better, as
continually warping the wings by bending down the extremities of the
rear spars was bound in time to produce ‘fatigue’ in that member and
lead to breakage; and the practice became completely obsolete during
the next two or three years.
The Gordon-Bennett race of September, 1913, was again won by a
Deperdussin machine, somewhat similar to that of the previous year,
but with exceedingly small wings, only 107 square feet in area. The
shape of these wings was instructive as showing how what, from the
general utility point of view, may be disadvantageous can, for a
special purpose, be turned to account. With a span of 21 feet, the
chord was 5 feet, giving the inefficient ‘aspect ratio’ of slightly
over 4 to 1 only. The object of this was to reduce the lift, and
therefore the resistance, to as low a point as possible. The total
weight was 1,500 lbs., giving a wing-loading of 14 lbs. per square
foot--a hitherto undreamt-of figure. The result was that the machine
took an enormously long run before starting; and after touching the
ground on landing ran for nearly a mile before stopping; but she beat
all records by attaining a speed of 126 miles per hour. Where this
performance is mainly interesting is in contrast to the machines of
1920, which with an even higher speed capacity would yet be able to
land at not more than 40 or 50 miles per hour, and would be thoroughly
efficient flying machines.
[Illustration: R.A.F. Aeroplane.]
The Rheims Aviation Meeting, at which the Gordon-Bennett race was
flown, also saw the first appearance of the Morane ‘Parasol’ monoplane.
The Morane monoplane had been for some time an interesting machine
as being the only type which had no fixed surface in rear to give
automatic stability, the movable elevator being balanced through being
hinged about one-third of the way back from the front edge. This made
the machine difficult to fly except in the hands of experts, but it was
very quick and handy on the controls and therefore useful for racing
purposes. In the ‘Parasol’ the modification was introduced of raising
the wing above the body, the pilot looking out beneath it, in order
to give as good a view as possible.
Before passing to the year 1914 mention should be made of the feat
performed by Nesteroff, a Russian, and Pégoud, a French pilot, who were
the first to demonstrate the possibilities of flying upside-down and
looping the loop. Though perhaps not coming strictly within the purview
of a chapter on design (though certain alterations were made to the
top wing-bracing of the machine for this purpose) this performance was
of extreme importance to the development of aviation by showing the
possibility of recovering, given reasonable height, from any position
in the air; which led designers to consider the extra stresses to which
an aeroplane might be subjected and to take steps to provide for them
by increasing strength where necessary.
When the year 1914 opened a speed of 126 miles per hour had been
attained and a height of 19,600 feet had been reached. The Sopwith
and Avro (the forerunner of the famous training machine of the War
period) were probably the two leading tractor biplanes of the world,
both two-seaters with a speed variation from 40 miles per hour up to
some 90 miles per hour with 80 horse-power engines. The French were
still pinning their faith mainly to monoplanes, while the Germans were
beginning to come into prominence with both monoplanes and biplanes
of the ‘Taube’ type. These had wings swept backward and also upturned
at the wing-tips which, though it gave a certain measure of automatic
stability, rendered the machine somewhat clumsy in the air, and their
performances were not on the whole as high as those of either France or
Great Britain.
Early in 1914 it became known that the experimental work of Edward
Busk--who was so lamentably killed during an experimental flight
later in the year--following upon the researches of Bairstow and
others had resulted in the production at the Royal Aircraft Factory at
Farnborough of a truly automatically stable aeroplane. This was the
‘R.E.’ (Reconnaissance Experimental), a development of the B.E. which
has already been referred to. The remarkable feature of this design
was that there was no particular device to which one could point out
as the cause of the stability. The stable result was attained simply
by detailed design of each part of the aeroplane, with due regard to
its relation to, and effect on, other parts in the air. Weights and
areas were so nicely arranged that under practically any conditions
the machine tended to right itself. It did not, therefore, claim to be
a machine which it was impossible to upset, but one which if left to
itself would tend to right itself from whatever direction a gust might
come. When the principles were extended to the ‘B.E. 2c’ type (largely
used at the outbreak of the War) the latter machine, if the engine were
switched off at a height of not less than 1,000 feet above the ground,
would after a few moments assume its correct gliding angle and glide
down to the ground.
The Paris Aero Salon of December, 1913, had been remarkable chiefly
for the large number of machines of which the chassis and bodywork had
been constructed of steel-tubing; for the excess of monoplanes over
biplanes; and (in the latter) predominance of ‘pusher’ machines (with
propeller in rear of the main planes) compared with the growing British
preference for ‘tractors’ (with air-screw in front). Incidentally, the
Maurice Farman, the last relic of the old type box-kite with elevator
in front appeared shorn of this prefix, and became known as the
‘short-horn’ in contradistinction to its front-elevatored predecessor
which, owing to its general reliability and easy flying capabilities,
had long been affectionately called the ‘mechanical cow.’ The 1913
Salon also saw some lingering attempts at attaining automatic stability
by pendulum and other freak devices.
Apart from the appearance of ‘R.E.1,’ perhaps the most notable
development towards the end of 1913 was the appearance of the Sopwith
‘Tabloid’ tractor biplane. This single-seater machine, evolved from
the two-seater previously referred to, fitted with a Gnome engine of
80 horse-power, had the, for those days, remarkable speed of 92 miles
an hour; while a still more notable feature was that it could remain
in level flight at not more than 37 miles per hour. This machine is of
particular importance because it was the prototype and forerunner of
the successive designs of single-seater scout fighting machines which
were used so extensively from 1914 to 1918. It was also probably the
first machine to be capable of reaching a height of 1,000 feet within
one minute. It was closely followed by the ‘Bristol Bullet,’ which was
exhibited at the Olympia Aero Show of March, 1914. This last pre-war
show was mainly remarkable for the good workmanship displayed--rather
than for any distinct advance in design. In fact, there was a notable
diversity in the types displayed, but in detailed design considerable
improvements were to be seen, such as the general adoption of stranded
steel cable in place of piano wire for the main bracing.
IV
THE WAR PERIOD
Up to this point an attempt has been made to give some idea of the
progress that was made during the eleven years that had elapsed since
the days of the Wrights’ first flights. Much advance had been made
and aeroplanes had settled down, superficially at any rate, into more
or less standardised forms in three main types--tractor monoplanes,
tractor biplanes, and pusher biplanes. Through the application of
the results of experiments with models in wind tunnels to full-scale
machines, considerable improvements had been made in the design of wing
sections, which had greatly increased the efficiency of aeroplanes by
raising the amount of ‘lift’ obtained from the wing compared with the
‘drag’ (or resistance to forward motion) which the same wing would
cause. In the same way the shape of bodies, interplane struts, etc.,
had been improved to be of better stream-line shape, for the further
reduction of resistance; while the problems of stability were beginning
to be tolerably well understood. Records (for what they are worth)
stood at 21,000 feet as far as height was concerned, 126 miles per hour
for speed, and 24 hours duration. That there was considerable room for
development is, however, evidenced by a statement made by the late
B. C. Hucks (the famous pilot) in the course of an address delivered
before the Royal Aeronautical Society in July, 1914. ‘I consider,’
he said, ‘that the present day standard of flying is due far more to
the improvement in piloting than to the improvement in machines....
I consider those (early 1914) machines are only slight improvements
on the machines of three years ago, and yet they are put through
evolutions which, at that time, were not even dreamed of. I can take
a good example of the way improvement in piloting has outdistanced
improvement in machines--in the case of myself, my ‘looping’ Blériot.
Most of you know that there is very little difference between that
machine and the 50 horse-power Blériot of three years ago.’ This
statement was, of course, to some extent an exaggeration and was by no
means agreed with by designers, but there was at the same time a germ
of truth in it. There is at any rate little doubt that the theory and
practice of aeroplane design made far greater strides towards becoming
an exact science during the four years of War than it had done during
the six or seven years preceding it.
It is impossible in the space at disposal to treat of this development
even with the meagre amount of detail that has been possible while
covering the ‘settling down’ period from 1911 to 1914, and it is
proposed, therefore, to indicate the improvements by sketching briefly
the more noticeable difference in various respects between the average
machine of 1914 and a similar machine of 1918.
In the first place, it was soon found that it was possible to obtain
greater efficiency and, in particular, higher speeds, from tractor
machines than from pusher machines with the air-screw behind the
main planes. This was for a variety of reasons connected with the
efficiency of propellers and the possibility of reducing resistance to
a greater extent in tractor machines by using a ‘stream-line’ fuselage
(or body) to connect the main planes with the tail. Full advantage of
this could not be taken, however, owing to the difficulty of fixing
a machine-gun in a forward direction owing to the presence of the
propeller. This was finally overcome by an ingenious device (known as
an ‘Interrupter gear’) which allowed the gun to fire only when none of
the propeller blades was passing in front of the muzzle. The monoplane
gradually fell into desuetude, mainly owing to the difficulty of
making that type adequately strong without it becoming prohibitively
heavy, and also because of its high landing speed and general lack of
manœuvrability. The triplane was also little used except in one or two
instances, and, practically speaking, every machine was of the biplane
tractor type.
A careful consideration of the salient features leading to maximum
efficiency in aeroplanes--particularly in regard to speed and climb,
which were the two most important military requirements--showed that
a vital feature was the reduction in the amount of weight lifted per
horse-power employed; which in 1914 averaged from 20 to 25 lbs. This
was effected both by gradual increase in the power and size of the
engines used and by great improvement in their detailed design (by
increasing compression ratio and saving weight whenever possible);
with the result that the motive power of single-seater aeroplanes
rose from 80 and 100 horse-power in 1914 to an average of 200 to 300
horse-power, while the actual weight of the engine fell from 3½-4 lbs.
per horse-power to an average of 2½ lbs. per horse-power. This meant
that while a pre-war engine of 100 horse-power would weigh some 400
lbs., the 1918 engine developing three times the power would have less
than double the weight. The result of this improvement was that a scout
aeroplane at the time of the Armistice would have 1 horse-power for
every 8 lbs. of weight lifted, compared with the 20 or 25 lbs. of its
1914 predecessors. This produced a considerable increase in the rate of
climb, a good postwar machine being able to reach 10,000 feet in about
5 minutes and 20,000 feet in under half an hour. The loading per square
foot was also considerably increased; this being rendered possible both
by improvement in the design of wing sections and by more scientific
construction giving increased strength. It will be remembered that in
the machine of the very early period each square foot of surface had
only to lift a weight of some 1½ to 2 lbs., which by 1914 had been
increased to about 4 lbs. By 1918 aeroplanes habitually had a loading
of 8 lbs. or more per square foot of area; which resulted in great
increase in speed. Although a speed of 126 miles per hour had been
attained by a specially designed racing machine over a short distance
in 1914, the average at that period little exceeded, if at all, 100
miles per hour; whereas in 1918 speeds of 130 miles per hour had become
a commonplace, and shortly afterwards a speed of over 166 miles an hour
was achieved.
In another direction, also, that of size, great developments were made.
Before the War a few machines fitted with more than one engine had been
built (the first being a triple Gnome-engined biplane built by Messrs
Short Bros. at Eastchurch in 1913), but none of large size had been
successfully produced, the total weight probably in no case exceeding
about 2 tons. In 1916, however, the twin engine Handley-Page biplane
was produced, to be followed by others both in this country and abroad,
which represented a very great increase in size and, consequently,
load-carrying capacity. By the end of the War period several types
were in existence weighing a total of 10 tons when fully loaded, of
which some 4 tons or more represented ‘useful load’ available for crew,
fuel, and bombs or passengers. This was attained through very careful
attention to detailed design, which showed that the material could be
employed more efficiently as size increased, and was also due to the
fact that a large machine was not liable to be put through the same
evolutions as a small machine, and therefore could safely be built
with a lower factor of safety. Owing to the fact that a wing section
which is adopted for carrying heavy loads usually has also a somewhat
low lift to drag ratio, and is not therefore productive of high speed,
these machines are not as fast as light scouts; but, nevertheless, they
proved themselves capable of achieving speeds of 100 miles an hour or
more in some cases; which was faster than the average small machine of
1914.
[Illustration: Bristol Fighters in formation.]
In one respect the development during the War may perhaps have proved
to be somewhat disappointing, as it might have been expected that
great improvements would be effected in metal construction, leading
almost to the abolition of wooden structures. Although, however, a
good deal of experimental work was done which resulted in overcoming
at any rate the worst of the difficulties, metal-built machines were
little used (except to a certain extent in Germany) chiefly on account
of the need for rapid production and the danger of delay resulting
from switching over from known and tried methods to experimental
types of construction. The Germans constructed some large machines,
such as the giant Siemens-Schukhert machine, entirely of metal except
for the wing covering, while the Fokker and Jünker firms about the
time of the Armistice in 1918 both produced monoplanes with very deep
all-metal wings (including the covering) which were entirely unstayed
externally, depending for their strength on internal bracing. In Great
Britain cable bracing gave place to a great extent to ‘stream-line
wires,’ which are steel rods rolled to a more or less oval section,
while tie-rods were also extensively used for the internal bracing
of the wings. Great developments in the economical use of material
were also made in the direction of using built-up main spars for the
wings and inter-plane struts; spars composed of a series of layers (or
‘laminations’) of different pieces of wood also being used.
Apart from the metallic construction of aeroplanes an enormous amount
of work was done in the testing of different steels and light alloys
for use in engines, and by the end of the War period a number of
aircraft engines were in use of which the pistons and other parts were
of such alloys; the chief difficulty having been not so much in the
design as in the successful heat-treatment and casting of the metal.
An important development in connection with the inspection and
testing of aircraft parts, particularly in the case of metal, was
the experimental application of X-ray photography, which showed up
latent defects, both in the material and in manufacture, which would
otherwise have passed unnoticed. This method was also used to test the
penetration of glue into the wood on each side of joints, so giving a
measure of the strength; and for the effect of ‘doping’ the wings,
dope being a film (of cellulose acetate dissolved in acetone with other
chemicals) applied to the covering of wings and bodies to render the
linen taut and weatherproof, besides giving it a smooth surface for the
lessening of ‘skin friction’ when passing rapidly through the air.
An important result of this experimental work was that it in many cases
enabled designers to produce aeroplane parts from less costly material
than had previously been considered necessary, without impairing the
strength. It may be mentioned that it was found undesirable to use
welded joints on aircraft in any part where the material is subject
to a tensile or bending load, owing to the danger resulting from bad
workmanship causing the material to become brittle--an effect which
cannot be discovered except by cutting through the weld, which, of
course, involves a test to destruction. Written, as it has been, in
August, 1920, it is impossible in this chapter to give any conception
of how the developments of War will be applied to commercial
aeroplanes, as few truly commercial machines have yet been designed,
and even those still show distinct traces of the survival of war
mentality. When, however, the inevitable recasting of ideas arrives, it
will become evident, whatever the apparent modification in the relative
importance of different aspects of design, that enormous advances were
made under the impetus of War which have left an indelible mark on
progress.
We have, during the seventeen years since aeroplanes first took the
air, seen them grow from tentative experimental structures of unknown
and unknowable performance to highly scientific products, of which not
only the performances (in speed, load-carrying capacity, and climb)
are known, but of which the precise strength and degree of stability
can be forecast with some accuracy on the drawing board. For the
rest, with the future lies--apart from some revolutionary change in
fundamental design--the steady development of a now well-tried and
well-found engineering structure.
PART III
AEROSTATICS
I
BEGINNINGS
Francesco Lana, with his ‘aerial ship’ stands as one of the first
great exponents of aerostatics; up to the time of the Mongolfier and
Charles balloon experiments, aerostatic and aerodynamic research
are so inextricably intermingled that it has been thought well to
treat of them as one, and thus the work of Lana, Veranzio and his
parachute, Guzman’s frauds, and the like, have already been sketched.
In connection with Guzman, Hildebrandt states in his _Airships Past
and Present_, a fairly exhaustive treatise on the subject up to
1906, the year of its publication, that there were two inventors--or
charlatans--Lorenzo de Guzman and a monk Bartolemeo Laurenzo, the
former of whom constructed an unsuccessful airship out of a wooden
basket covered with paper, while the latter made certain experiments
with a machine of which no description remains. A third de Guzman,
some twenty-five years later, announced that he had constructed a
flying machine, with which he proposed to fly from a tower to prove
his success to the public. The lack of record of any fatal accident
overtaking him about that time seems to show that the experiment was
not carried out.
Galien, a French monk, published a book _L’art de naviguer dans l’air_
in 1757, in which it was conjectured that the air at high levels was
lighter than that immediately over the surface of the earth. Galien
proposed to bring down the upper layers of air and with them fill a
vessel, which by Archimidean principle would rise through the heavier
atmosphere. If one went high enough, said Galien, the air would be two
thousand times as light as water, and it would be possible to construct
an airship, with this light air as lifting factor, which should be as
large as the town of Avignon, and carry four million passengers with
their baggage. How this high air was to be obtained is matter for
conjecture--Galien seems to have thought in a vicious circle, in which
the vessel that must rise to obtain the light air must first be filled
with it in order to rise.
Cavendish’s discovery of hydrogen in 1776 set men thinking, and soon a
certain Doctor Black was suggesting that vessels might be filled with
hydrogen, in order that they might rise in the air. Black, however,
did not get beyond suggestion; it was Leo Cavallo who first made
experiments with hydrogen, beginning with filling soap bubbles, and
passing on to bladders and special paper bags. In these latter the gas
escaped, and Cavallo was about to try goldbeaters’ skin at the time
that the Mongolfiers came into the field with their hot air balloon.
Joseph and Stephen Mongolfier, sons of a wealthy French paper
manufacturer, carried out many experiments in physics, and Joseph
interested himself in the study of aeronautics some time before the
first balloon was constructed by the brothers--he is said to have made
a parachute descent from the roof of his house as early as 1771, but
of this there is no proof. Galien’s idea, together with study of the
movement of clouds, gave Joseph some hope of achieving aerostation
through Galien’s schemes, and the first experiments were made by
passing steam into a receiver, which, of course, tended to rise--but
the rapid condensation of the steam prevented the receiver from more
than threatening ascent. The experiments were continued with smoke,
which produced only a slightly better effect, and, moreover, the paper
bag into which the smoke was induced permitted of escape through its
pores; finding this method a failure the brothers desisted until
Priestley’s work became known to them, and they conceived the use of
hydrogen as a lifting factor. Trying this with paper bags, they found
that the hydrogen escaped through the pores of the paper.
Their first balloon, made of paper, reverted to the hot-air principle;
they lighted a fire of wool and wet straw under the balloon--and as a
matter of course the balloon took fire after very little experiment;
thereupon they constructed a second, having a capacity of 700 cubic
feet, and this rose to a height of over 1,000 feet. Such a success gave
them confidence, and they gave their first public exhibition on June
5th, 1783, with a balloon constructed of paper and of a circumference
of 112 feet. A fire was lighted under this balloon, which, after rising
to a height of 1,000 feet, descended through the cooling of the air
inside a matter of ten minutes. At this the Académie des Sciences
invited the brothers to conduct experiments in Paris.
The Mongolfiers were undoubtedly first to send up balloons, but other
experimenters were not far behind them, and before they could get to
Paris in response to their invitation, Charles, a prominent physicist
of those days, had constructed a balloon of silk, which he proofed
against escape of gas with rubber--the Roberts had just succeeded in
dissolving this substance to permit of making a suitable coating for
the silk. With a quarter of a ton of sulphuric acid, and half a ton
of iron filings and turnings, sufficient hydrogen was generated in
four days to fill Charles’s balloon, which went up on August 29th,
1783. Although the day was wet, Paris turned out to the number of over
300,000 in the Champs de Mars, and cannon were fired to announce the
ascent of the balloon. This, rising very rapidly, disappeared amid the
rain clouds, but, probably bursting through no outlet being provided
to compensate for the escape of gas, fell soon in the neighbourhood of
Paris. Here peasants, ascribing evil supernatural influence to the fall
of such a thing from nowhere, went at it with the implements of their
craft--forks, hoes, and the like--and maltreated it severely, finally
attaching it to a horse’s tail and dragging it about until it was mere
rag and scrap.
Meanwhile, Joseph Mongolfier, having come to Paris, set about the
construction of a balloon out of linen; this was in three diverse
sections, the top being a cone 30 feet in depth, the middle a cylinder
42 feet in diameter by 26 feet in depth, and the bottom another cone
20 feet in depth from junction with the cylindrical portion to its
point. The balloon was both lined and covered with paper, decorated in
blue and gold. Before ever an ascent could be attempted this ambitious
balloon was caught in a heavy rainstorm which reduced its paper
covering to pulp and tore the linen at its seams, so that a supervening
strong wind tore the whole thing to shreds.
Mongolfier’s next balloon was spherical, having a capacity of 52,000
cubic feet. It was made from water-proofed linen, and on September
19th, 1783, it made an ascent for the palace courtyard at Versailles,
taking up as passengers a cock, a sheep, and a duck. A rent at the top
of the balloon caused it to descend within eight minutes, and the duck
and sheep were found none the worse for being the first living things
to leave the earth in a balloon, but the cock, evidently suffering, was
thought to have been affected by the rarefaction of the atmosphere at
the tremendous height reached--for at that time the general opinion was
that the atmosphere did not extend more than four or five miles above
the earth’s surface. It transpired later that the sheep had trampled on
the cock, causing more solid injury than any that might be inflicted by
rarefied air in an eight-minute ascent and descent of a balloon.
For achieving this flight Joseph Mongolfier received from the King
of France a pension of £40, while Stephen was given the Order of St
Michael, and a patent of nobility was granted to their father. They
were made members of the Legion d’Honneur, and a scientific deputation,
of which Faujas de Saint-Fond, who had raised the funds with which
Charles’s hydrogen balloon was constructed, presented to Stephen
Mongolfier a gold medal struck in honour of his aerial conquest.
Since Joseph appears to have had quite as much share in the success
as Stephen, the presentation of the medal to one brother only was in
questionable taste, unless it was intended to balance Joseph’s pension.
Once aerostation had been proved possible, many people began the
construction of small balloons--the whole thing was regarded as a
matter of spectacles and as a form of amusement by the great majority.
A certain Baron de Beaumanoir made the first balloon of goldbeaters’
skin, this being eighteen inches in diameter, and using hydrogen as a
lifting factor. Few people saw any possibilities in aerostation, in
spite of the adventures of the duck and sheep and cock; voyages to
the moon were talked and written, and there was more of levity than
seriousness over ballooning as a rule. The classic retort of Benjamin
Franklin stands as an exception to the general rule: asked what was the
use of ballooning--‘What’s the use of a baby?’ he countered, and the
spirit of that reply brought both the dirigible and the aeroplane to
being, later.
The next noteworthy balloon was one by Stephen Mongolfier, designed
to take up passengers, and therefore of rather large dimensions, as
these things went then. The capacity was 100,000 cubic feet, the depth
being 85 feet, and the exterior was very gaily decorated. A short,
cylindrical opening was made at the lower extremity, and under this
a fire-pan was suspended, above the passenger car of the balloon.
On October 15th, 1783, Pilatre de Rozier made the first balloon
ascent--but the balloon was held captive, and only allowed to rise to
a height of 80 feet. But, a little later in 1783, Rozier secured the
honour of making the first ascent in a free balloon, taking up with
him the Marquis d’Arlandes. It had been originally intended that two
criminals, condemned to death, should risk their lives in the perilous
venture, with the prospect of a free pardon if they made a safe
descent, but d’Arlandes got the royal consent to accompany Rozier, and
the criminals lost their chance. Rozier and d’Arlandes made a voyage
lasting for twenty-five minutes, and, on landing, the balloon collapsed
with such rapidity as almost to suffocate Rozier, who, however, was
dragged out to safety by d’Arlandes. This first aerostatic journey took
place on November 21st, 1783.
Some seven months later, on June 4th, 1784, a Madame Thible ascended
in a free balloon, reaching a height of 9,000 feet, and making a
journey which lasted for forty-five minutes--the great King Gustavus
of Sweden witnessed this ascent. France grew used to balloon ascents
in the course of a few months, in spite of the brewing of such a storm
as might have been calculated to wipe out all but purely political
interests. Meanwhile, interest in the new discovery spread across the
Channel, and on September 15th, 1784, one Vincent Lunardi made the
first balloon voyage in England, starting from the Artillery Ground at
Chelsea, with a cat and dog as passengers, and landing in a field in
the parish of Standon, near Ware. There is a rather rare book which
gives a very detailed account of this first ascent in England, one
copy of which is in the library of the Royal Aeronautical Society; the
venturesome Lunardi won a greater measure of fame through his exploit
than did Cody for his infinitely more courageous and--from a scientific
point of view--valuable first aeroplane ascent in this country.
The Mongolfier type of balloon, depending on hot air for its lifting
power, was soon realised as having dangerous limitations. There was
always a possibility of the balloon catching fire while it was being
filled, and on landing there was further danger from the hot pan
which kept up the supply of hot air on the voyage--the collapsing
balloon fell on the pan, inevitably. The scientist Saussure, observing
the filling of the balloons very carefully, ascertained that it was
rarefaction of the air which was responsible for the lifting power,
and not the heat in itself, and, owing to the rarefaction of the air
at normal temperature at great heights above the earth, the limit of
ascent for a balloon of the Mongolfier type was estimated by him at
under 9,000 feet. Moreover, since the amount of fuel that could be
carried for maintaining the heat of the balloon after inflation was
subject to definite limits, prescribed by the carrying capacity of the
balloon, the duration of the journey was necessarily limited just as
strictly.
These considerations tended to turn the minds of those interested
in aerostation to consideration of the hydrogen balloon evolved by
Professor Charles. Certain improvements had been made by Charles
since his first construction; he employed rubber-coated silk in the
construction of a balloon of 30 feet diameter, and provided a net for
distributing the pressure uniformly over the surface of the envelope;
this net covered the top half of the balloon, and from its lower edge
dependent ropes hung to join on a wooden ring, from which the car of
the balloon was suspended--apart from the extension of the net so as to
cover in the whole of the envelope, the spherical balloon of to-day is
virtually identical with that of Charles in its method of construction.
He introduced the valve at the top of the balloon, by which escape of
gas could be controlled, operating his valve by means of ropes which
depended to the car of the balloon, and he also inserted a tube, of
about 7 inches diameter, at the bottom of the balloon, not only for
purposes of inflation, but also to provide a means of escape for gas in
case of expansion due to atmospheric conditions.
Sulphuric acid and iron filings were used by Charles for filling his
balloon, which required three days and three nights for the generation
of its 14,000 cubic feet of hydrogen gas. The inflation was completed
on December 1st, 1783, and the fittings carried included a barometer
and a grapnel form of anchor. In addition to this, Charles provided
the first ‘ballon sondé’ in the form of a small pilot balloon which
he handed to Mongolfier to launch before his own ascent, in order to
determine the direction and velocity of the wind. It was a graceful
compliment to his rival, and indicated that, although they were both
working to the one end, their rivalry was not a matter of bitterness.
Ascending on December 1st, 1783, Charles took with him one of the
brothers Robert, and with him made the record journey up to that date,
covering a period of three and three-quarter hours, in which time they
journeyed some forty miles. Robert then landed, and Charles ascended
again alone, reaching such a height as to feel the effects of the
rarefaction of the air, this very largely due to the rapidity of his
ascent. Opening the valve at the top of the balloon, he descended
thirty-five minutes after leaving Robert behind, and came to earth a
few miles from the point of the first descent. His discomfort over the
rapid ascent was mainly due to the fact that, when Robert landed, he
forgot to compensate for the reduction of weight by taking in further
ballast, but the ascent proved the value of the tube at the bottom of
the balloon envelope, for the gas escaped very rapidly in that second
ascent, and, but for the tube, the balloon must inevitably have burst
in the air, with fatal results for Charles.
As in the case of aeroplane flight, as soon as the balloon was
proved practicable the flight across the English Channel was talked
of, and Rozier, who had the honour of the first flight, announced his
intention of being first to cross. But Blanchard, who had an idea
for a ‘flying car,’ anticipated him, and made a start from Dover on
January 7th, 1785, taking with him an American doctor named Jeffries.
Blanchard fitted out his craft for the journey very thoroughly, taking
provisions, oars, and even wings, for propulsion in case of need. He
took so much, in fact, that as soon as the balloon lifted clear of the
ground the whole of the ballast had to be jettisoned, lest the balloon
should drop into the sea. Half-way across the Channel the sinking of
the balloon warned Blanchard that he had to part with more than ballast
to accomplish the journey, and all the equipment went, together with
certain books and papers that were on board the car. The balloon looked
perilously like collapsing, and both Blanchard and Jeffries began to
undress in order further to lighten their craft--Jeffries even proposed
a heroic dive to save the situation, but suddenly the balloon rose
sufficiently to clear the French coast, and the two voyagers landed at
a point near Calais in the Forest of Guines, where a marble column was
subsequently erected to commemorate the great feat.
Rozier, although not first across, determined to be second, and for
that purpose he constructed a balloon which was to owe its buoyancy
to a combination of the hydrogen and hot air principles. There was
a spherical hydrogen balloon above, and beneath it a cylindrical
container which could be filled with hot air, thus compensating for the
leakage of gas from the hydrogen portion of the balloon--regulating the
heat of his fire, he thought, would give him perfect control in the
matter of ascending and descending.
On July 16th, 1785, a favourable breeze gave Rozier his opportunity of
starting from the French coast, and with a passenger aboard he cast
off in his balloon, which he had named the ‘Aero-Mongolfiere.’ There
was a rapid rise at first, and then for a time the balloon remained
stationary over the land, after which a cloud suddenly appeared round
the balloon, denoting that an explosion had taken place. Both Rozier
and his companion were killed in the fall, so that he, first to leave
the earth by balloon, was also first victim to the art of aerostation.
There followed, naturally, a lull in the enthusiasm with which
ballooning had been taken up, so far as France was concerned. In Italy,
however, Count Zambeccari took up hot-air ballooning, using a spirit
lamp to give him buoyancy, and on the first occasion when the balloon
car was set on fire Zambeccari let down his passenger by means of the
anchor rope, and managed to extinguish the fire while in the air. This
reduced the buoyancy of the balloon to such an extent that it fell
into the Adriatic and was totally wrecked, Zambeccari being rescued by
fishermen. He continued to experiment up to 1812, when he attempted to
ascend at Bologna; the spirit in his lamp was upset by the collision
of the car with a tree, and the car was again set on fire. Zambeccari
jumped from the car when it was over fifty feet above level ground, and
was killed. With him the Rozier type of balloon, combining the hydrogen
and hot air principles, disappeared; the combination was obviously too
dangerous to be practical.
The brothers Robert were first to note how the heat of the sun
acted on the gases within a balloon envelope, and it has since been
ascertained that sun rays will heat the gas in a balloon to as much
as 80 degrees Fahrenheit greater temperature than the surrounding
atmosphere; hydrogen, being less affected by change of temperature than
coal gas, is the most suitable filling element, and coal gas comes next
as the medium of buoyancy. This for the free and non-navigable balloon,
though for the airship, carrying means of combustion, and in military
work liable to ignition by explosives, the gas helium seems likely to
replace hydrogen, being non-combustible.
In spite of the development of the dirigible airship, there remains
work for the free, spherical type of balloon in the scientific field.
Blanchard’s companion on the first Channel crossing by balloon, Dr
Jeffries, was the first balloonist to ascend for purely scientific
purposes; as early as 1784 he made an ascent to a height of 9,000 feet,
and observed a fall in temperature of from 51 degrees--at the level
of London, where he began his ascent--to 29 degrees at the maximum
height reached. He took up an electrometer, a hydrometer, a compass, a
thermometer, and a Toricelli barometer, together with bottles of water,
in order to collect samples of the air at different heights. In 1785 he
made a second ascent, when trigonometrical observations of the height
of the balloon were made from the French coast, giving an altitude of
4,800 feet.
The matter was taken up on its scientific side very early in America,
experiments in Philadelphia being almost simultaneous with those of the
Mongolfiers in France. The flight of Rozier and d’Arlandes inspired
two members of the Philadelphia Philosophical Academy to construct a
balloon or series of balloons of their own design; they made a machine
which consisted of no less than 47 small hydrogen balloons attached
to a wicker car, and made certain preliminary trials, using animals
as passengers. This was followed by a captive ascent with a man as
passenger, and eventually by the first free ascent in America, which
was undertaken by one James Wilcox, a carpenter, on December 28th 1783.
Wilcox, fearful of falling into a river, attempted to regulate his
landing by cutting slits in some of the supporting balloons, which was
the method adopted for regulating ascent or descent in this machine.
He first cut three, and then, finding that the effect produced was not
sufficient, cut three more, and then another five--eleven out of the
forty-seven. The result was so swift a descent that he dislocated his
wrist on landing.
A NOTE ON BALLONETS OR AIR BAGS.
Meusnier, toward the end of the eighteenth century, was first to
conceive the idea of compensating for the loss of gas due to expansion
by fitting to the interior of a free balloon a ballonet, or air bag,
which could be pumped full of air so as to retain the shape and
rigidity of the envelope.
The ballonet became particularly valuable as soon as airship
construction became general, and it was in the course of advance in
Astra Torres design that the project was introduced of using the
ballonets in order to give inclination from the horizontal. In the
earlier Astra Torres, trimming was accomplished by moving the car fore
and aft--this in itself was an advance on the separate ‘sliding weight’
principle--and this was the method followed in the Astra Torres bought
by the British Government from France in 1912 for training airship
pilots. Subsequently, the two ballonets fitted inside the envelope were
made to serve for trimming by the extent of their inflation, and this
method of securing inclination proved the best until exterior rudders,
and greater engine power, supplanted it, as in the Zeppelin and, in
fact, all rigid types.
In the kite balloon, the ballonet serves the purpose of a rudder,
filling itself through the opening being kept pointed toward the
wind--there is an ingenious type of air scoop with non-return valve
which assures perfect inflation. In the S. S. type of airship, two
ballonets are provided, the supply of air being taken from the
propeller draught by a slanting aluminium tube to the underside of the
envelope, where it meets a longitudinal fabric hose which connects the
two ballonet air inlets. In this hose the non-return air valves, known
as ‘crab-pots,’ are fitted, on either side of the junction with the
air-scoop. Two automatic air valves, one for each ballonet, are fitted
in the underside of the envelope, and, as the air pressure tends to
open these instead of keeping them shut, the spring of the valve is set
inside the envelope. Each spring is set to open at a pressure of 25 to
28 mm.
II
THE FIRST DIRIGIBLES
Having got off the earth, the very early balloonists set about the task
of finding a means of navigating the air, but, lacking steam or other
accessory power to human muscle, they failed to solve the problem.
Joseph Mongolfier speedily exploded the idea of propelling a balloon
either by means of oars or sails, pointing out that even in a dead
calm a speed of five miles an hour would be the limit achieved. Still,
sailing balloons were constructed, even up to the time of Andree, the
explorer, who proposed to retard the speed of the balloon by ropes
dragging on the ground, and then to spread a sail which should catch
the wind and permit of deviation of the course. It has been proved that
slight divergences from the course of the wind can be obtained by this
means, but no real navigation of the air could be thus accomplished.
Professor Wellner, of Brunn, brought up the idea of a sailing balloon
in more practical fashion in 1883. He observed that surfaces inclined
to the horizontal have a slight lateral motion in rising and falling,
and deduced that by alternate lowering and raising of such surfaces
he would be able to navigate the air, regulating ascent and descent
by increasing or decreasing the temperature of his buoyant medium in
the balloon. He calculated that a balloon, 50 feet in diameter and
150 feet in length, with a vertical surface in front and a horizontal
surface behind, might be navigated at a speed of ten miles per hour,
and in actual tests at Brunn he proved that a single rise and fall
moved the balloon three miles against the wind. His ideas were further
developed by Lebaudy in the construction of the early French dirigibles.
According to Hildebrandt,[11] the first sailing balloon was built in
1784 by Guyot, who made his balloon egg-shaped, with the smaller end
at the back and the longer axis horizontal; oars were intended to
propel the craft, and naturally it was a failure. Carra proposed the
use of paddle wheels, a step in the right direction, by mounting them
on the sides of the car, but the improvement was only slight. Guyton
de Morveau, entrusted by the Academy of Dijon with the building of a
sailing balloon, first used a vertical rudder at the rear end of his
construction--it survives in the modern dirigible. His construction
included sails and oars, but, lacking steam or other than human
propulsive power, the airship was a failure equally with Guyot’s.
Two priests, Miollan and Janinet, proposed to drive balloons through
the air by the forcible expulsion of the hot air in the envelope
from the rear of the balloon. An opening was made about half-way
up the envelope, through which the hot air was to escape, buoyancy
being maintained by a pan of combustibles in the car. Unfortunately,
this development of the Mongolfier type never got a trial, for those
who were to be spectators of the first flight grew exasperated at
successive delays, and in the end, thinking that the balloon would
never rise, they destroyed it.
Meusnier, a French general, first conceived the idea of compensating
for loss of gas by carrying an air bag inside the balloon, in order
to maintain the full expansion of the envelope. The brothers Robert
constructed the first balloon in which this was tried, and placed the
air bag near the neck of the balloon, which was intended to be driven
by oars, and steered by a rudder. A violent swirl of wind which was
encountered on the first ascent tore away the oars and rudder and broke
the ropes which held the air bag in position; the bag fell into the
opening of the neck and stopped it up, preventing the escape of gas
under expansion. The Duc de Chartres, who was aboard, realised the
extreme danger of the envelope bursting as the balloon ascended, and
at 16,000 feet he thrust a staff through the envelope--another account
says that he slit it with his sword--and thus prevented disaster. The
descent after this rip in the fabric was swift, but the passengers got
off without injury in the landing.
Meusnier, experimenting in various ways, experimented with regard to
the resistance offered by various shapes to the air, and found that an
elliptical shape was best; he proposed to make the car boat-shaped, in
order further to decrease the resistance, and he advocated an entirely
rigid connection between the car and the body of the balloon, as
indispensable to a dirigible.[12] He suggested using three propellers,
which were to be driven by hand by means of pulleys, and calculated
that a crew of eighty would be required to furnish sufficient motive
power. Horizontal fins were to be used to assure stability, and
Meusnier thoroughly investigated the pressures exerted by gases,
in order to ascertain the stresses to which the envelope would be
subjected. More important still, he went into detail with regard to
the use of air bags, in order to retain the shape of the balloon under
varying pressures of gas due to expansion and consequent losses; he
proposed two separate envelopes, the inner one containing gas, and the
space between it and the outer one being filled with air. Further,
by compressing the air inside the air bag, the rate of ascent or
descent could be regulated. Lebaudy, acting on this principle, found
it possible to pump air at the rate of 35 cubic feet per second, thus
making good loss of ballast which had to be thrown overboard.
Meusnier’s balloon, of course, was never constructed, but his ideas
have been of value to aerostation up to the present time. His career
ended in the revolutionary army in 1793, when he was killed in the
fighting before Mayence, and the King of Prussia ordered all firing
to cease until Meusnier had been buried. No other genius came forward
to carry on his work, and it was realised that human muscle could not
drive a balloon with certainty through the air; experiment in this
direction was abandoned for nearly sixty years, until in 1852 Giffard
brought the first practicable power-driven dirigible to being.
Giffard, inventor of the steam injector, had already made balloon
ascents when he turned to aeronautical propulsion, and constructed a
steam engine of 5 horse-power with a weight of only 100 lbs.--a great
achievement for his day. Having got his engine, he set about making
the balloon which it was to drive; this he built with the aid of two
other enthusiasts, diverging from Meusnier’s ideas by making the ends
pointed, and keeping the body narrowed from Meusnier’s ellipse to a
shape more resembling a rather fat cigar. The length was 144 feet, and
the greatest diameter only 40 feet, while the capacity was 88,000 cubic
feet. A net which covered the envelope of the balloon supported a spar,
66 feet in length, at the end of which a triangular sail was placed
vertically to act as rudder. The car, slung 20 feet below the spar,
carried the engine and propeller. Engine and boiler together weighed
350 lbs., and drove the 11 foot propeller at 110 revolutions per minute.
As precaution against explosion, Giffard arranged wire gauze in front
of the stoke-hole of his boiler, and provided an exhaust pipe which
discharged the waste gases from the engine in a downward direction.
With this first dirigible he attained to a speed of between 6 and 8
feet per second, thus proving that the propulsion of a balloon was a
possibility, now that steam had come to supplement human effort.
Three years later he built a second dirigible, reducing the diameter
and increasing the length of the gas envelope, with a view to reducing
air resistance. The length of this was 230 feet, the diameter only 33
feet, and the capacity was 113,000 cubic feet, while the upper part of
the envelope, to which the covering net was attached, was specially
covered to ensure a stiffening effect. The car of this dirigible was
dropped rather lower than that of the first machine, in order to
provide more thoroughly against the danger of explosions. Giffard, with
a companion named Yon as passenger, took a trial trip on this vessel,
and made a journey against the wind, though slowly. In commencing to
descend, the nose of the envelope tilted upwards, and the weight of
the car and its contents caused the net to slip, so that just before
the dirigible reached the ground, the envelope burst. Both Giffard and
his companion escaped with very slight injuries.
Plans were immediately made for the construction of a third dirigible,
which was to be 1,970 feet in length, 98 feet in extreme diameter, and
to have a capacity of 7,800,000 cubic feet of gas. The engine of this
giant was to have weighed 30 tons, and with it Giffard expected to
attain a speed of 40 miles per hour. Cost prevented the scheme being
carried out, and Giffard went on designing small steam engines until
his invention of the steam injector gave him the funds to turn to
dirigibles again. He built a captive balloon for the great exhibition
in London in 1868, at a cost of nearly £30,000, and designed a
dirigible balloon which was to have held a million and three-quarters
cubic feet of gas, carry two boilers, and cost about £40,000. The plans
were thoroughly worked out, down to the last detail, but the dirigible
was never constructed. Giffard went blind, and died in 1882--he stands
as the great pioneer of dirigible construction, more on the strength of
the two vessels which he actually built than on that of the ambitious
later conceptions of his brain.
In 1872 Dupuy de Lome, commissioned by the French government, built a
dirigible which he proposed to drive by man-power--it was anticipated
that the vessel would be of use in the siege of Paris, but it was not
actually tested till after the conclusion of the war. The length of
this vessel was 118 feet, its greatest diameter 49 feet, the ends being
pointed, and the motive power was by a propeller which was revolved by
the efforts of eight men. The vessel attained to about the same speed
as Giffard’s steam-driven airship; it was capable of carrying fourteen
men, who, apart from these engaged in driving the propeller, had to
manipulate the pumps which controlled the air bags inside the gas
envelope.
In the same year Paul Haenlein, working in Vienna, produced an airship
which was a direct forerunner of the Lebaudy type, 164 feet in length,
30 feet greatest diameter, and with a cubic capacity of 85,000 feet.
Semi-rigidity was attained by placing the car as close to the envelope
as possible, suspending it by crossed ropes, and the motive power was
a gas engine of the Lenoir type, having four horizontal cylinders, and
giving about 5 horse-power with a consumption of about 250 cubic feet
of gas per hour. This gas was sucked from the envelope of the balloon,
which was kept fully inflated by pumping in compensating air to the
air bags inside the main envelope. A propeller, 15 feet in diameter,
was driven by the Lenoir engine at 40 revolutions per minute. This
was the first instance of the use of an internal combustion engine in
connection with aeronautical experiments.
The envelope of this dirigible was rendered airtight by means of
internal rubber coating, with a thinner film on the outside. Coal gas,
used for inflation, formed a suitable fuel for the engine, but limited
the height to which the dirigible could ascend. Such trials as were
made were carried out with the dirigible held captive, and a speed of
15 feet per second was attained. Full experiment was prevented through
funds running low, but Haenlein’s work constituted a distinct advance
on all that had been done previously.
Two brothers, Albert and Gaston Tissandier, were next to enter the
field of dirigible construction; they had experimented with balloons
during the Franco-Prussian War, and had attempted to get into Paris by
balloon during the siege, but it was not until 1882 that they produced
their dirigible.
This was 92 feet in length and 32 feet in greatest diameter, with
a cubic capacity of 37,500 feet, and the fabric used was varnished
cambric. The car was made of bamboo rods, and in addition to its crew
of three, it carried a Siemens dynamo, with 24 bichromate cells, each
of which weighed 17 lbs. The motor gave out 1½ horse-power, which was
sufficient to drive the vessel at a speed of up to 10 feet per second.
This was not so good as Haenlein’s previous attempt and, after £2,000
had been spent, the Tissandiers abandoned their experiments, since a
5-mile breeze was sufficient to nullify the power of the motor.
Renard, a French officer who had studied the problem of dirigible
construction since 1878, associated himself first with a brother
officer named La Haye, and subsequently with another officer, Krebs, in
the construction of the second dirigible to be electrically-propelled.
La Haye first approached Colonel Laussedat, in charge of the Engineers
of the French Army, with a view to obtaining funds, but was refused,
in consequence of the practical failure of all experiments since 1870.
Renard, with whom Krebs had now associated himself, thereupon went to
Gambetta, and succeeded in getting a promise of a grant of £8,000 for
the work; with this promise Renard and Krebs set to work.
They built their airship in torpedo shape, 165 feet in length, and of
just over 27 feet greatest diameter--the greatest diameter was at the
front, and the cubic capacity was 66,000 feet. The car itself was 108
feet in length, and 4½ feet broad, covered with silk over the bamboo
framework. The 23 foot diameter propeller was of wood, and was driven
by an electric motor connected to an accumulator, and yielding 8.5
horse-power. The sweep of the propeller, which might have brought it
in contact with the ground in landing, was counteracted by rendering
it possible to raise the axis on which the blades were mounted,
and a guide rope was used to obviate damage altogether, in case of
rapid descent. There was also a ‘sliding weight’ which was movable
to any required position to shift the centre of gravity as desired.
Altogether, with passengers and ballast aboard, the craft weighed two
tons.
In the afternoon of August 9th, 1884, Renard and Krebs ascended in
the dirigible--which they had named ‘La France,’ from the military
ballooning ground at Chalais-Meudon, making a circular flight of about
five miles, the latter part of which was in the face of a slight
wind. They found that the vessel answered well to her rudder, and the
five-mile flight was made successfully in a period of 23 minutes.
Subsequent experimental flights determined that the air speed of the
dirigible was no less than 14½ miles per hour, by far the best that
had so far been accomplished in dirigible flight. Seven flights in all
were made, and of these five were completely successful, the dirigible
returning to its starting point with no difficulty. On the other two
flights it had to be towed back.
Renard attempted to repeat his construction on a larger scale, but
funds would not permit, and the type was abandoned; the motive power
was not sufficient to permit of more than short flights, and even to
the present time electric motors, with their necessary accumulators,
are far too cumbrous to compete with the self-contained internal
combustion engine. France had to wait for the Lebaudy brothers, just as
Germany had to wait for Zeppelin and Parseval.
Two German experimenters, Baumgarten and Wolfert, fitted a Daimler
motor to a dirigible balloon which made its first ascent at Leipzig in
1880. This vessel had three cars, and placing a passenger in one of the
outer cars[13] distributed the load unevenly, so that the whole vessel
tilted over and crashed to the earth, the occupants luckily escaping
without injury. After Baumgarten’s death, Wolfert determined to carry
on with his experiments, and, having achieved a certain measure of
success, he announced an ascent to take place on the Tempelhofer
Field, near Berlin, on June 12th, 1897. The vessel, travelling with
the wind, reached a height of 600 feet, when the exhaust of the motor
communicated flame to the envelope of the balloon, and Wolfert,
together with a passenger he carried, was either killed by the fall or
burnt to death on the ground. Giffard had taken special precautions to
avoid an accident of this nature, and Wolfert, failing to observe equal
care, paid the full penalty.
Platz, a German soldier, attempting an ascent on the Tempelhofer Field
in the Schwartz airship in 1897, merely proved the dirigible a failure.
The vessel was of aluminium, 0.008 inch in thickness, strengthened by
an aluminium lattice work; the motor was two-cylindered petrol-driven;
at the first trial the metal developed such leaks that the vessel came
to the ground within four miles of its starting point. Platz, who was
aboard alone as crew, succeeded in escaping by jumping clear before
the car touched earth, but the shock of alighting broke up the balloon,
and a following high wind completed the work of full destruction. A
second account says that Platz, finding the propellers insufficient to
drive the vessel against the wind, opened the valve and descended too
rapidly.
The envelope of this dirigible was 156 feet in length, and the method
of filling was that of pushing in bags, fill them with gas, and
then pulling them to pieces and tearing them out of the body of the
balloon. A second contemplated method of filling was by placing a linen
envelope inside the aluminium casing, blowing it out with air, and then
admitting the gas between the linen and the aluminium outer casing.
This would compress the air out of the linen envelope, which was to be
withdrawn when the aluminium casing had been completely filled with gas.
All this, however, assumes that the Schwartz type--the first rigid
dirigible, by the way--would prove successful. As it proved a failure
on the first trial, the problem of filling it did not arise again.
By this time Zeppelin, retired from the German army, had begun to
devote himself to the study of dirigible construction, and, a year
after Schwartz had made his experiment and had failed, he got together
sufficient funds for the formation of a limited liability company, and
started on the construction of the first of his series of airships. The
age of tentative experiment was over, and, forerunner of the success
of the heavier-than-air type of flying machine, successful dirigible
flight was accomplished by Zeppelin in Germany, and by Santos-Dumont in
France.
III
SANTOS-DUMONT
A Brazilian by birth, Santos-Dumont began in Paris in the year 1898 to
make history, which he subsequently wrote. His book, _My Airships_,
is a record of his eight years of work on lighter-than-air machines,
a period in which he constructed no less than fourteen dirigible
balloons, beginning with a cubic capacity of 6,350 feet, and an engine
of 3 horse-power, and rising to a cubic capacity of 71,000 feet on the
tenth dirigible he constructed, and an engine of 60 horse-power, which
was fitted to the seventh machine in order of construction, the one
which he built after winning the Deutsch Prize.
The student of dirigible construction is recommended to Santos-Dumont’s
own book not only as a full record of his work, but also as one of
the best stories of aerial navigation that has ever been written.
Throughout all his experiments, he adhered to the non-rigid type; his
first dirigible made its first flight on September 18th, 1898, starting
from the Jardin d’Acclimatation to the west of Paris; he calculated
that his 3 horse-power engine would yield sufficient power to enable
him to steer clear of the trees with which the starting-point was
surrounded, but, yielding to the advice of professional aeronauts who
were present, with regard to the placing of the dirigible for his
start, he tore the envelope against the trees. Two days later, having
repaired the balloon, he made an ascent of 1,300 feet. In descending,
the hydrogen left in the balloon contracted, and Santos-Dumont narrowly
escaped a serious accident in coming to the ground.
His second machine, built in the early spring of 1899, held over 7,000
cubic feet of gas and gave a further 44 lbs. of ascensional force. The
balloon envelope was very long and very narrow; the first attempt at
flight was made in wind and rain, and the weather caused sufficient
contraction of the hydrogen for a wind gust to double the machine
up and toss it into the trees near its starting-point. The inventor
immediately set about the construction of ‘Santos-Dumont No. 3,’ on
which he made a number of successful flights, beginning on November
13th, 1899. On the last of his flights, he lost the rudder of the
machine and made a fortunate landing at Ivry. He did not repair the
balloon, considering it too clumsy in form and its motor too small.
Consequently No. 4 was constructed, being finished on the 1st August,
1900. It had a cubic capacity of 14,800 feet, a length of 129 feet and
greatest diameter of 16.7 feet, the power plant being a 7 horse-power
Buchet motor. Santos-Dumont sat on a bicycle saddle fixed to the long
bar suspended under the machine, which also supported motor, propeller,
ballast, and fuel. The experiment of placing the propeller at the stem
instead of at the stern was tried, and the motor gave it a speed of 100
revolutions per minute. Professor Langley witnessed the trials of the
machine, which proved before the members of the International Congress
of Aeronautics, on September 19th, that it was capable of holding its
own against a strong wind.
Finding that the cords with which his dirigible balloon cars were
suspended offered almost as much resistance to the air as did the
balloon itself, Santos-Dumont substituted piano wire and found that the
alteration constituted greater progress than many a more showy device.
He altered the shape and size of his No. 4 to a certain extent and
fitted a motor of 12 horse-power. Gravity was controlled by shifting
weights worked by a cord; rudder and propeller were both placed at the
stern. In Santos-Dumont’s book there is a certain amount of confusion
between the No. 4 and No. 5 airships, until he explains that ‘No.
5’ is the reconstructed ‘No. 4.’ It was with No. 5 that he won the
Encouragement Prize presented by the Scientific Commission of the Paris
Aero Club. This he devoted to the first aeronaut who between May and
October of 1900 should start from St Cloud, round the Eiffel Tower,
and return. If not won in that year, the prize was to remain open the
following year from May 1st to October 1st and so on annually until
won. This was a simplification of the conditions of the Deutsch Prize
itself, the winning of which involved a journey of 11 kilometres in 30
minutes.
The Santos-Dumont No. 5, which was in reality the modified No. 4 with
new keel, motor, and propeller, did the course of the Deutsch Prize,
but with it Santos-Dumont made no attempt to win the prize until July
of 1901, when he completed the course in 40 minutes, but tore his
balloon in landing. On the 8th August, with his balloon leaking, he
made a second attempt, and narrowly escaped disaster, the airship being
entirely wrecked. Thereupon he built No. 6 with a cubic capacity of
22,239 feet and a lifting power of 1,518 lbs. With this machine he won
the Deutsch Prize on October 19th, 1901, starting with the disadvantage
of a side wind of 20 feet per second. He reached the Eiffel Tower
in 9 minutes and, through miscalculating his turn, only just missed
colliding with it. He got No. 6 under control again and succeeded in
getting back to his starting-point in 29½ minutes, thus winning the
125,000 francs which constituted the Deutsch Prize, together with a
similar sum granted to him by the Brazilian Government for the exploit.
The greater part of this money was given by Santos-Dumont to charities.
He went on building after this until he had made fourteen non-rigid
dirigibles; of these No. 12 was placed at the disposal of the military
authorities, while the rest, except for one that was sold to an
American and made only one trip, were matters of experiment for their
maker. His conclusions from his experiments may be gathered from his
own work:--
‘On Friday, 31st July, 1903, Commandant Hirschauer and
Lieutenant-Colonel Bourdeaux spent the afternoon with me at my airship
station at Neuilly St James, where I had my three newest airships--the
racing ‘No. 7,’ the omnibus ‘No. 10,’ and the runabout ‘No. 9’--ready
for their study. Briefly, I may say that the opinions expressed by the
representatives of the Minister of War were so unreservedly favourable
that a practical test of a novel character was decided to be made.
Should the airship chosen pass successfully through it the result will
be conclusive of its military value.
‘Now that these particular experiments are leaving my exclusively
private control I will say no more of them than what has been already
published in the French press. The test will probably consist of an
attempt to enter one of the French frontier towns, such as Belfort or
Nancy, on the same day that the airship leaves Paris. It will not,
of course, be necessary to make the whole journey in the airship. A
military railway wagon may be assigned to carry it, with its balloon
uninflated, with tubes of hydrogen to fill it, and with all the
necessary machinery and instruments arranged beside it. At some station
a short distance from the town to be entered the wagon may be uncoupled
from the train, and a sufficient number of soldiers accompanying the
officers will unload the airship and its appliances, transport the
whole to the nearest open space, and at once begin inflating the
balloon. Within two hours from quitting the train the airship may be
ready for its flight to the interior of the technically-besieged town.
‘Such may be the outline of the task--a task presented imperiously to
French balloonists by the events of 1870–1, and which all the devotion
and science of the Tissandier brothers failed to accomplish. To-day
the problem may be set with better hope of success. All the essential
difficulties may be revived by the marking out of a hostile zone around
the town that must be entered; from beyond the outer edge of this zone,
then, the airship will rise and take its flight--across it.
‘Will the airship be able to rise out of rifle range? I have always
been the first to insist that the normal place of the airship is in
low altitudes, and I shall have written this book to little purpose
if I have not shown the reader the real dangers attending any brusque
vertical mounting to considerable heights. For this we have the
terrible Severo accident before our eyes. In particular, I have
expressed astonishment at hearing of experimenters rising to these
altitudes without adequate purpose in their early stages of experience
with dirigible balloons. All this is very different, however, from a
reasoned, cautious mounting, whose necessity has been foreseen and
prepared for.’
Probably owing to the fact that his engines were not of sufficient
power, Santos-Dumont cannot be said to have solved the problem of the
military airship, although the French Government bought one of his
vessels. At the same time, he accomplished much in furthering and
inciting experiment with dirigible airships, and he will always rank
high among the pioneers of aerostation. His experiments might have gone
further had not the Wright brothers’ success in America and French
interest in the problem of the heavier-than-air machine turned him
from the study of dirigibles to that of the aeroplane, in which also
he takes high rank among the pioneers, leaving the construction of a
successful military dirigible to such men as the Lebaudy brothers,
Major Parseval, and Zeppelin.
IV
THE MILITARY DIRIGIBLE
Although French and German experiment in connection with the production
of an airship which should be suitable for military purposes proceeded
side by side, it is necessary to outline the development in the two
countries separately, owing to the differing character of the work
carried out. So far as France is concerned, experiment began with the
Lebaudy brothers, originally sugar refiners, who turned their energies
to airship construction in 1899. Three years of work went to the
production of their first vessel, which was launched in 1902, having
been constructed by them together with a balloon manufacturer named
Surcouf and an engineer, Julliot. The Lebaudy airships were what is
known as semi-rigids, having a spar which ran practically the full
length of the gas bag to which it was attached in such a way as to
distribute the load evenly. The car was suspended from the spar, at
the rear end of which both horizontal and vertical rudders were fixed,
whilst stabilising fins were provided at the stern of the gas envelope
itself. The first of the Lebaudy vessels was named the ‘Jaune’; its
length was 183 feet and its maximum diameter 30 feet, while the cubic
capacity was 80,000 feet. The power unit was a 40 horse-power Daimler
motor, driving two propellers and giving a maximum speed of 26 miles
per hour. This vessel made 29 trips, the last of which took place in
November, 1902, when the airship was wrecked through collision with a
tree.
[Illustration: Astra Torres.]
The second airship of Lebaudy construction was 7 feet longer than the
first, and had a capacity of 94,000 cubic feet of gas with a triple air
bag of 17,500 cubic feet to compensate for loss of gas; this latter was
kept inflated by a rotary fan. The vessel was eventually taken over by
the French Government and may be counted the first dirigible airship
considered fit on its tests for military service.
Later vessels of the Lebaudy type were the ‘Patrie’ and ‘Republique,’
in which both size and method of construction surpassed those of the
two first attempts. The ‘Patrie’ was fitted with a 60 horse-power
engine which gave a speed of 28 miles an hour, while the vessel had a
radius of 280 miles, carrying a crew of nine. In the winter of 1907 the
‘Patrie’ was anchored at Verdun, and encountered a gale which broke her
hold on her mooring-ropes. She drifted derelict westward across France,
the Channel, and the British Isles, and was lost in the Atlantic.
The ‘Republique’ had an 80 horse-power motor, which, however, only gave
her the same speed as the ‘Patrie.’ She was launched in July, 1908,
and within three months came to an end which constituted a tragedy
for France. A propeller burst while the vessel was in the air, and
one blade, flying toward the envelope, tore in it a great gash; the
airship crashed to earth, and the two officers and two non-commissioned
officers who were in the car were instantaneously killed.
The Clement Bayard, and subsequently the Astra-Torres, non-rigids,
followed on the early Lebaudys and carried French dirigible
construction up to 1912. The Clement Bayard was a simple non-rigid
having four lobes at the stern end to assist stability. These were
found to retard the speed of the airship, which in the second and
more successful construction was driven by a Clement Bayard motor of
100 horse-power at a speed of 30 miles an hour. On August 23rd, 1909,
while being tried for acceptance by the military authorities, this
vessel achieved a record by flying at a height of 5,000 feet for two
hours. The Astra-Torres non-rigids were designed by a Spaniard, Señor
Torres, and built by the Astra Company. The envelope was of trefoil
shape, this being due to the interior rigging from the suspension band;
the exterior appearance is that of two lobes side by side, overlaid
by a third. The interior rigging, which was adopted with a view to
decreasing air resistance, supports a low-hung car from the centre of
the envelope; steering is accomplished by means of horizontal planes
fixed on the envelope at the stern, and vertical planes depending
beneath the envelope, also at the stern end.
One of the most successful of French pre-war dirigibles was a Clement
Bayard built in 1912. In this twin propellers were placed at the front
and horizontal and vertical rudders in a sort of box formation under
the envelope at the stern. The envelope was stream-lined, while the
car of the machine was placed well forward with horizontal controlling
planes above it and immediately behind the propellers. This airship,
which was named ‘Dupuy de Lome,’ may be ranked as about the most
successful non-rigid dirigible constructed prior to the War.
Experiments with non-rigids in Germany was mainly carried on by Major
Parseval, who produced his first vessel in 1906. The main feature
of this airship consisted in variation in length of the suspension
cables at the will of the operator, so that the envelope could be
given an upward tilt while the car remained horizontal in order to
give the vessel greater efficiency in climbing. In this machine, the
propeller was placed above and forward of the car, and the controlling
planes were fixed directly to the envelope near the forward end. A
second vessel differed from the first mainly in the matter of its
larger size, variable suspension being again employed, together with a
similar method of control. The vessel was moderately successful, and
under Major Parseval’s direction a third was constructed for passenger
carrying, with two engines of 120 horse-power, each driving propellers
of 13 feet diameter. This was the most successful of the early German
dirigibles; it made a number of voyages with a dozen passengers in
addition to its crew, as well as proving its value for military
purposes by use as a scout machine in manœuvres. Later Parsevals were
constructed of stream-line form, about 300 feet in length, and with
engines sufficiently powerful to give them speeds up to 50 miles an
hour.
Major Von Gross, commander of a Balloon Battalion, produced semi-rigid
dirigibles from 1907 onward. The second of these, driven by two 75
horse-power Daimler motors, was capable of a speed of 27 miles an
hour; in September of 1908 she made a trip from and back to Berlin
which lasted 13 hours, in which period she covered 176 miles with four
passengers and reached a height of 4,000 feet. Her successor, launched
in April of 1909, carried a wireless installation, and the next to
this, driven by four motors of 75 horse-power each, reached a speed of
45 miles an hour. As this vessel was constructed for military purposes,
very few details either of its speed or method of construction were
made public.
Practically all these vessels were discounted by the work of
Ferdinand von Zeppelin, who set out from the first with the idea of
constructing a rigid dirigible. Beginning in 1898, he built a balloon
on an aluminium framework covered with linen and silk, and divided
into interior compartments holding linen bags which were capable of
containing nearly 400,000 cubic feet of hydrogen. The total length of
this first Zeppelin airship was 420 feet and the diameter 38 feet.
Two cars were rigidly attached to the envelope, each carrying a 16
horse-power motor, driving propellers which were rigidly connected to
the aluminium framework of the balloon. Vertical and horizontal screws
were used for lifting and forward driving and a sliding weight was used
to raise or lower the stem of the vessel out of the horizontal in order
to rise or descend without altering the load by loss of ballast or the
lift by loss of gas.
The first trial of this vessel was made in July of 1900, and was
singularly unfortunate. The winch by which the sliding weight was
operated broke, and the balloon was so bent that the working of the
propellers was interfered with, as was the steering. A speed of 13 feet
per second was attained, but on descending the airship ran against some
piles and was further damaged. Repairs were completed by the end of
September, 1900, and on a second trial flight made on October 21st a
speed of 30 feet per second was reached.
[Illustration: Zeppelin, pre-war type.]
Zeppelin was far from satisfied with the performance of this vessel,
and he therefore set about collecting funds for the construction of
a second, which was completed in 1905. By this time the internal
combustion engine had been greatly improved, and without any increase
of weight, Zeppelin was able to instal two motors of 85 horse-power
each. The total capacity was 367,000 cubic feet of hydrogen, carried
in 16 gas bags inside the framework, and the weight of the whole
construction was 9 tons--a ton less than that of the first Zeppelin
airship. Three vertical planes at front and rear controlled horizontal
steering, while rise and fall was controlled by horizontal planes
arranged in box form. Accident attended the first trial of this second
airship, which took place over the Bodensee on November 30th, 1905. ‘It
had been intended to tow the raft, to which it was anchored, further
from the shore against the wind. But the water was too low to allow
the use of the raft. The balloon was therefore mounted on pontoons,
pulled out into the lake, and taken in tow by a motor-boat. It was
caught by a strong wind which was blowing from the shore, and driven
ahead at such a rate that it overtook the motor-boat. The tow rope was
therefore at once cut, but it unexpectedly formed into knots and became
entangled with the airship, pulling the front end down into the water.
The balloon was then caught by the wind and lifted into the air, when
the propellers were set in motion. The front end was at this instant
pointing in a downward direction, and consequently it shot into the
water, where it was found necessary to open the valves.’[14]
The damage done was repaired within six weeks, and the second trial
was made on January 17th, 1906. The lifting force was too great for
the weight, and the dirigible jumped immediately to 1,500 feet. The
propellers were started, and the dirigible brought to a lower level,
when it was found possible to drive against the wind. The steering
arrangements were found too sensitive, and the motors were stopped,
when the vessel was carried by the wind until it was over land--it had
been intended that the trial should be completed over water. A descent
was successfully accomplished and the dirigible was anchored for the
night, but a gale caused it so much damage that it had to be broken
up. It had achieved a speed of 30 feet per second with the motors
developing only 36 horse-power and, gathering from this what speed
might have been accomplished with the full 170 horse-power, Zeppelin
set about the construction of No. 3, with which a number of successful
voyages were made, proving the value of the type for military purposes.
No. 4 was the most notable of the early Zeppelins, as much on account
of its disastrous end as by reason of any superior merit in comparison
with No. 3. The main innovation consisted in attaching a triangular
keel to the under side of the envelope, with two gaps beneath which the
cars were suspended. Two Daimler Mercedes motors of 110 horse-power
each were placed one in each car, and the vessel carried sufficient
fuel for a 60-hour cruise with the motors running at full speed. Each
motor drove a pair of three-bladed metal propellers rigidly attached
to the framework of the envelope and about 15 feet in diameter. There
was a vertical rudder at the stern of the envelope and horizontal
controlling planes were fixed on the sides of the envelope. The best
performances and the end of this dirigible were summarised as follows
by Major Squier:--
‘Its best performances were two long trips performed during the
summer of 1908. The first, on July 4th, lasted exactly 12 hours,
during which time it covered a distance of 235 miles, crossing the
mountains to Lucerne and Zurich, and returning to the balloon-house
near Friedrichshafen, on Lake Constance. The average speed on this trip
was 32 miles per hour. On August 4th, this airship attempted a 24-hour
flight, which was one of the requirements made for its acceptance
by the Government. It left Friedrichshafen in the morning with the
intention of following the Rhine as far as Mainz, and then returning
to its starting-point, straight across the country. A stop of 3 hours
30 minutes was made in the afternoon of the first day on the Rhine, to
repair the engine. On the return, a second stop was found necessary
near Stuttgart, due to difficulties with the motors, and some loss of
gas. While anchored to the ground, a storm arose which broke loose
the anchorage, and, as the balloon rose in the air, it exploded and
took fire (due to causes which have never been actually determined and
published) and fell to the ground, where it was completely destroyed.
On this journey, which lasted in all 31 hours 15 minutes, the airship
was in the air 20 hours 45 minutes, and covered a total distance of 378
miles.
‘The patriotism of the German nation was aroused. Subscriptions
were immediately started, and in a short space of time a quarter of
a million pounds had been raised. A Zeppelin Society was formed to
direct the expenditure of this fund. Seventeen thousand pounds has
been expended in purchasing land near Friederichshafen; workshops were
erected, and it was announced that within one year the construction
of eight airships of the Zeppelin type would be completed. Since the
disaster to ‘Zeppelin IV.’ the Crown Prince of Germany made a trip in
‘Zeppelin No. 3,’ which had been called back into service, and within
a very few days the German Emperor visited Friedrichshafen for the
purpose of seeing the airship in flight. He decorated Count Zeppelin
with the Order of the Black Eagle. German patriotism and enthusiasm
has gone further, and the “German Association for an Aerial Fleet” has
been organised in sections throughout the country. It announces its
intention of building 50 garages (hangars) for housing airships.’
By January of 1909, with well over a quarter of a million in hand for
the construction of Zeppelin airships, No. 3 was again brought out,
probably in order to maintain public enthusiasm in respect of the
possible new engine of war. In March of that year No. 3 made a voyage
which lasted for 4 hours over and in the vicinity of Lake Constance; it
carried 26 passengers for a distance of nearly 150 miles.
Before the end of March, Count Zeppelin determined to voyage from
Friedrichshafen to Munich, together with the crew of the airship
and four military officers. Starting at four in the morning and
ascertaining their route from the lights of railway stations and the
ringing of bells in the towns passed over, the journey was completed
by nine o’clock, but a strong south-west gale prevented the intended
landing. The airship was driven before the wind until three o’clock
in the afternoon, when it landed safely near Dingolfing; by the next
morning the wind had fallen considerably and the airship returned to
Munich and landed on the parade ground as originally intended. At about
3.30 in the afternoon, the homeward journey was begun, Friedrichshafen
being reached at about 7.30.
These trials demonstrated that sufficient progress had been made to
justify the construction of Zeppelin airships for use with the German
army. No. 3 had been manœuvred safely if not successfully in half a
gale of wind, and henceforth it was known as ‘SMS. Zeppelin I.,’ at the
bidding of the German Emperor, while the construction of ‘SMS. Zeppelin
II.’ was rapidly proceeded with. The fifth construction of Count
Zeppelin’s was 446 feet in length, 42½ feet in diameter, and contained
530,000 cubic feet of hydrogen gas in 17 separate compartments. Trial
flights were made on the 26th May, 1909, and a week later she made a
record voyage of 940 miles, the route being from Lake Constance over
Ulm, Nuremberg, Leipzig, Bitterfeld, Weimar, Heilbronn, and Stuttgart,
descending near Goppingen; the time occupied in the flight was upwards
of 38 hours.
In landing, the airship collided with a pear-tree, which damaged the
bows and tore open two sections of the envelope, but repairs on the
spot enabled the return journey to Friedrichshafen to be begun 24
hours later. In spite of the mishap the Zeppelin had once more proved
itself as a possible engine of war, and thenceforth Germany pinned
its faith to the dirigible, only developing the aeroplane to such an
extent as to keep abreast of other nations. By the outbreak of war,
nearly 30 Zeppelins had been constructed; considerably more than
half of these were destroyed in various ways, but the experiments
carried on with each example of the type permitted of improvements
being made. The first fatality occurred in September, 1913, when the
fourteenth Zeppelin to be constructed, known as Naval Zeppelin L.1,
was wrecked in the North Sea by a sudden storm and her crew of thirteen
were drowned. About three weeks after this, Naval Zeppelin L.2, the
eighteenth in order of building, exploded in mid-air while manœuvring
over Johannisthal. She was carrying a crew of 25, who were all killed.
By 1912 the success of the Zeppelin type brought imitators. Chief among
them was the Schutte-Lanz, a Mannheim firm, which produced a rigid
dirigible with a wooden framework, wire braced. This was not a cylinder
like the Zeppelin, but reverted to the cigar shape and contained about
the same amount of gas as the Zeppelin type. The Schutte-Lanz was made
with two gondolas rigidly attached to the envelope in which the gas
bags were placed. The method of construction involved greater weight
than was the case with the Zeppelin, but the second of these vessels,
built with three gondolas containing engines, and a navigating cabin
built into the hull of the airship itself, proved quite successful as
a naval scout until wrecked on the islands off the coast of Denmark
late in 1914. The last Schutte-Lanz to be constructed was used by the
Germans for raiding England, and was eventually brought down in flames
at Cowley.
V
BRITISH AIRSHIP DESIGN
As was the case with the aeroplane, Great Britain left France and
Germany to make the running in the early days of airship construction;
the balloon section of the Royal Engineers was compelled to confine
its energies to work with balloons pure and simple until well after
the twentieth century had dawned, and such experiments as were made in
England were done by private initiative. As far back as 1900 Doctor
Barton built an airship at the Alexandra Palace and voyaged across
London in it. Four years later Mr E. T. Willows of Cardiff produced
the first successful British dirigible, a semi-rigid 74 feet in
length and 18 feet in diameter, engined with a 7 horse-power Peugot
twin-cylindered motor. This drove a two-bladed propeller at the stern
for propulsion, and also actuated a pair of auxiliary propellers at
the front which could be varied in their direction so as to control
the right and left movements of the airship. This device was patented
and the patent was taken over by the British Government, which by
1908 found Mr Willow’s work of sufficient interest to regard it as
furnishing data for experiment at the balloon factory at Farnborough.
In 1909, Willows steered one of his dirigibles to London from Cardiff
in a little less than ten hours, making an average speed of over 14
miles an hour. The best speed accomplished was probably considerably
greater than this, for at intervals of a few miles, Willows descended
near the earth to ascertain his whereabouts with the help of a
megaphone. It must be added that he carried a compass in addition to
his megaphone. He set out for Paris in November of 1910, reached the
French coast, and landed near Douai. Some damage was sustained in this
landing, but, after repair, the trip to Paris was completed.
Meanwhile the Government balloon factory at Farnborough began airship
construction in 1907; Colonel Capper, R.E., and S. F. Cody were jointly
concerned in the production of a semi-rigid. Fifteen thicknesses of
goldbeaters’ skin--about the most expensive covering obtainable--were
used for the envelope, which was 25 feet in diameter. A slight shower
of rain in which the airship was caught led to its wreckage, owing to
the absorbent quality of the goldbeaters’ skin, whereupon Capper and
Cody set to work to reproduce the airship and its defects on a larger
scale. The first had been named ‘Nulli Secundus’ and the second was
named ‘Nulli Secundus II.’ _Punch_ very appropriately suggested that
the first vessel ought to have been named ‘Nulli Primus,’ while a
possible third should be christened ‘Nulli Tertius.’ ‘Nulli Secundus
II.’ was fitted with a 100 horse-power engine and had an envelope of 42
feet in diameter, the goldbeaters’ skin being covered in fabric and the
car being suspended by four bands which encircled the balloon envelope.
In October of 1907, ‘Nulli Secundus II.’ made a trial flight from
Farnborough to London and was anchored at the Crystal Palace. The wind
sprung up and took the vessel away from its mooring ropes, wrecking
it after the one flight.
[Illustration: The Army Airship ‘Beta’ at the Manœuvres.
The ‘Beta’ going up to reconnoitre.]
Stagnation followed until early in 1909, when a small airship fitted
with two 12 horse-power motors and named the ‘Baby’ was turned out from
the balloon factory. This was almost egg-shaped, the blunt end being
forward, and three inflated fins being placed at the tail as control
members. A long car with rudder and elevator at its rear-end carried
the engines and crew; the ‘Baby’ made some fairly successful flights
and gave a good deal of useful data for the construction of later
vessels.
Next to this was ‘Army Airship 2A’ launched early in 1910 and larger,
longer, and narrower in design than the Baby. The engine was an 80
horse-power Green motor which drove two pairs of propellers; small
inflated control members were fitted at the stern end of the envelope,
which was 154 feet in length. The suspended car was 84 feet long,
carrying both engines and crew, and the Willows idea of swivelling
propellers for governing the direction was used in this vessel. In June
of that year a new, small-type dirigible, the ‘Beta,’ was produced,
driven by a 30 horse-power Green engine with which she flew over 3,000
miles. She was the most successful British dirigible constructed up
to that time, and her successor, the ‘Gamma,’ was built on similar
lines. The ‘Gamma’ was a larger vessel, however, produced in 1912, with
flat, controlling fins and rudder at the rear end of the envelope,
and with the conventional long car suspended at some distance beneath
the gas bag. By this time, the mooring mast, carrying a cap of which
the concave side fitted over the convex nose of the airship, had been
originated. The cap was swivelled, and, when attached to it, an
airship was held nose on to the wind, thus reducing by more than half
the dangers attendant on mooring dirigibles in the open.
Private subscription under the auspices of the _Morning Post_ got
together sufficient funds in 1910 for the purchase of a Lebaudy
airship, which was built in France, flown across the Channel, and
presented to the Army Airship Fleet. This dirigible was 337 feet long,
and was driven by two 135 horse-power Panhard motors, each of which
actuated two propellers. The journey from Moisson to Aldershot was
completed at a speed of 36 miles an hour, but the airship was damaged
while being towed into its shed. On May of the following year, the
Lebaudy was brought out for a flight, but, in landing, the guide rope
fouled in trees and sheds and brought the airship broadside on to the
wind; she was driven into some trees and wrecked to such an extent that
rebuilding was considered an impossibility. A Clement Bayard, bought by
the army airship section, became scrap after even less flying than had
been accomplished by the Lebaudy.
In April of 1910, the Admiralty determined on a naval air service, and
set about the production of rigid airships which should be able to
compete with Zeppelins as naval scouts. The construction was entrusted
to Vickers, Ltd., who set about the task at their Barrow works and
built something which, when tested after a year’s work, was found
incapable of lifting its own weight. This defect was remedied by a
series of alterations, and meanwhile the unofficial title of ‘Mayfly’
was given to the vessel.
[Illustration: The S.S. type of airship.
H.M. King George inspecting.]
Taken over by the Admiralty before she had passed any flying tests,
the ‘Mayfly’ was brought out on September 24th, 1911, for a trial trip,
being towed out from her shed by a tug. When half out from the shed,
the envelope was caught by a light cross-wind, and, in spite of the
pull from the tug, the great fabric broke in half, nearly drowning the
crew, who had to dive in order to get clear of the wreckage.
There was considerable similarity in form, though not in performance,
between the Mayfly and the pre-war Zeppelin. The former was 510 feet in
length, cylindrical in form, with a diameter of 48 feet, and divided
into 19 gas-bag compartments. The motive power consisted of two 200
horse-power Wolseley engines. After its failure, the Naval Air Service
bought an Astra-Torres airship from France and a Parseval from Germany,
both of which proved very useful in the early days of the War, doing
patrol work over the Channel before the Blimps came into being.
Early in 1915 the ‘Blimp’ or ‘S.S.’ type of coastal airship was evolved
in response to the demand for a vessel which could be turned out
quickly and in quantities. There was urgent demand, voiced by Lord
Fisher, for a type of vessel capable of maintaining anti-submarine
patrol off the British coasts, and the first S.S. airships were made by
combining a gasbag with the most available type of aeroplane fuselage
and engine, and fitting steering gear. The ‘Blimp’ consisted of a B.E.
fuselage with engine and geared-down propeller, and seating for pilot
and observer, attached to an envelope about 150 feet in length. With a
speed of between 35 and 40 miles an hour, the ‘Blimp’ had a cruising
capacity of about ten hours; it was fitted with wireless set, camera,
machine-gun, and bombs, and for submarine spotting and patrol work
generally it proved invaluable, though owing to low engine power and
comparatively small size, its uses were restricted to reasonably fair
weather. For work farther out at sea and in all weathers, airships
known as the coast patrol type, and more commonly as ‘coastals,’
were built, and later the ‘N.S.’ or North Sea type, still larger and
more weather-worthy, followed. By the time the last year of the War
came, Britain led the world in the design of non-rigid and semi-rigid
dirigibles. The ‘S.S.’ or ‘Blimp’ had been improved to a speed of 50
miles an hour, carrying a crew of three, and the endurance record for
the type was 18½ hours, while one of them had reached a height of
10,000 feet. The North Sea type of non-rigid was capable of travelling
over 20 hours at full speed, or forty hours at cruising speed, and the
number of non-rigids belonging to the British Navy exceeded that of any
other country.
It was owing to the incapacity--apparent or real--of the British
military or naval designers to produce a satisfactory rigid airship
that the ‘N.S.’ airship was evolved. The first of this type was
produced in 1916, and on her trials she was voted an unqualified
success, in consequence of which the building of several more was
pushed on. The envelope, of 360,000 cubic feet capacity, was made on
the Astra-Torres principle of three lobes, giving a trefoil section.
The ship carried four fins, to three of which the elevator and rudder
flaps were attached; petrol tanks were placed inside the envelope,
under which was rigged a long covered-in car, built up of a light
steel tubular framework 35 feet in length. The forward portion was
covered with duralumin sheeting, an aluminium alloy which, unlike
aluminium itself, is not affected by the action of sea air and water,
and the remainder with fabric laced to the framework. Windows and
port-holes were provided to give light to the crew, and the controls
and navigating instruments were placed forward, with the sleeping
accommodation aft. The engines were mounted in a power unit structure,
separate from the car and connected by wooden gangways supported by
wire cables. A complete electrical installation of two dynamos and
batteries for lights, signalling lamps, wireless, telephones, etc., was
carried, and the motive power consisted of either two 250 horse-power
Rolls-Royce engines or two 240 horse-power Fiat engines. The principal
dimensions of this type are length 262 feet, horizontal diameter 56
feet 9 inches, vertical diameter 69 feet 3 inches. The gross lift is
24,300 lbs. and the disposable lift without crew, petrol, oil, and
ballast 8,500 lbs. The normal crew carried for patrol work was ten
officers and men. This type holds the record of 101 hours continuous
flight on patrol duty.
In the matter of rigid design it was not until 1913 that the British
Admiralty got over the fact that the ‘Mayfly’ would not, and decided
on a further attempt at the construction of a rigid dirigible. The
contract for this was signed in March of 1914; work was suspended in
the following February and begun again in July, 1915, but it was not
until January of 1917 that the ship was finished, while her trials
were not completed until March of 1917, when she was taken over by
the Admiralty. The details of the construction and trial of this
vessel, known as ‘No. 9,’ go to show that she did not quite fill the
contract requirements in respect of disposable lift until a number
of alterations had been made. The contract specified that a speed of
at least 45 miles per hour was to be attained at full engine power,
while a minimum disposable lift of 5 tons was to be available for
movable weights, and the airship was to be capable of rising to a
height of 2,000 feet. Driven by four Wolseley Maybach engines of 180
horse-power each, the lift of the vessel was not sufficient, so it was
decided to remove the two engines in the after car and replace them by
a single engine of 250 horse-power. With this the vessel reached the
contract speed of 45 miles per hour with a cruising radius of 18 hours,
equivalent to 800 miles when the engines were running at full speed.
The vessel served admirably as a training airship, for, by the time she
was completed, the No. 23 class of rigid airship had come to being, and
thus No. 9 was already out of date.
Three of the 23 class were completed by the end of 1917; it was
stipulated that they should be built with a speed of at least 55
miles per hour, a minimum disposable lift of 8 tons, and a capability
of rising at an average rate of not less than 1,000 feet per minute
to a height of 3,000 feet. The motive power consisted of four 250
horse-power Rolls-Royce engines, one in each of the forward and
after cars and two in a centre car. Four-bladed propellers were used
throughout the ship.
[Illustration: Coastal airship, showing gun on top of envelope.]
A 23X type followed on the 23 class, but by the time two ships had been
completed, this was practically obsolete. The No. 31 class followed the
23X; it was built on Schutte-Lanz lines, 615 feet in length, 66 feet
diameter, and a million and a half cubic feet capacity. The hull was
similar to the later types of Zeppelin in shape, with a tapering stern
and a bluff, rounded bow. Five cars each carrying a 250 horse-power
Rolls-Royce engine, driving a single fixed propeller, were fitted,
and on her trials R.31 performed well, especially in the matter of
speed. But the experiment of constructing in wood in the Schutte-Lanz
way adopted with this vessel resulted in failure eventually, and the
type was abandoned.
Meanwhile, Germany had been pushing forward Zeppelin design and
straining every nerve in the improvement of rigid dirigible
construction, until L.33 was evolved; she was generally known as a
super-Zeppelin, and on September 24th, 1916, six weeks after her
launching, she was damaged by gun-fire in a raid over London, being
eventually compelled to come to earth at Little Wigborough in Essex.
The crew gave themselves up after having set fire to the ship, and
though the fabric was totally destroyed, the structure of the hull
remained intact, so that just as Germany was able to evolve the
Gotha bomber from the Handley-Page delivered at Lille, British naval
constructors were able to evolve the R.33 type of airship from the
Zeppelin framework delivered at Little Wigborough. Two vessels, R.33
and R.34, were laid down for completion; three others were also put
down for construction, but, while R.33 and R.34 were built almost
entirely from the data gathered from the wrecked L.33, the three later
vessels embody more modern design, including a number of improvements,
and more especially greater disposable lift. It has been commented
that while the British authorities were building R.33 and R.34,
Germany constructed 30 Zeppelins on 4 slips, for which reason it may
be reckoned a matter for congratulation that the rigid airship did not
decide the fate of the War. The following particulars of construction
of the R.33 and R.34 types are as given by Major Whale in his survey of
_British Airships_:--
‘In all its main features the hull structure of R.33 and R.34 follows
the design of the wrecked German Zeppelin airship L.33. The hull
follows more nearly a true stream-line shape than in the previous ships
constructed of duralumin, in which a greater proportion of the greater
length was parallel-sided. The Germans adopted this new shape from the
Schutte-Lanz design and have not departed from this practice. This
consists of a short, parallel body with a long, rounded bow and a long
tapering stem culminating in a point. The overall length of the ship is
643 feet with a diameter of 79 feet and an extreme height of 92 feet.
The type of girders in this class has been much altered from those in
previous ships. The hull is fitted with an internal triangular keel
throughout practically the entire length. This forms the main corridor
of the ship, and is fitted with a footway down the centre for its
entire length. It contains water ballast and petrol tanks, bomb storage
and crew accommodation, and the various control wires, petrol pipes,
and electric leads are carried along the lower part.
Throughout this internal corridor runs a bridge girder, from which
the petrol and water ballast tanks are supported. These tanks are so
arranged that they can be dropped clear of the ship. Amidships is the
cabin space with sufficient room for a crew of twenty-five. Hammocks
can be swung from the bridge girder before mentioned.
In accordance with the latest Zeppelin practice, monoplane rudders and
elevators are fitted to the horizontal and vertical fins.
The ship is supported in the air by nineteen gas bags, which give a
total capacity of approximately two million cubic feet of gas. The
gross lift works out at approximately 59½ tons, of which the total
fixed weight is 33 tons, giving a disposable lift of 26½ tons.
The arrangement of cars is as follows: At the forward end the control
car is slung, which contains all navigating instruments and the various
controls. Adjoining this is the wireless cabin, which is also fitted
for wireless telephony. Immediately aft of this is the forward power
car containing one engine, which gives the appearance that the whole is
one large car.
Amidships are two wing cars, each containing a single engine. These
are small and just accommodate the engines with sufficient room for
mechanics to attend to them. Further aft is another larger car which
contains an auxiliary control position and two engines.
It will thus be seen that five engines are installed in the ship; these
are all of the same type and horse-power, namely, 250 horse-power
Sunbeam. R.33 was constructed by Messrs Armstrong, Whitworth, Ltd.;
while her sister ship R.34 was built by Messrs Beardmore on the Clyde.’
Of the two vessels, R.34 appeared rather more airworthy than her sister
ship; the lift of the ship justified the carrying of a greater quantity
of fuel than had been provided for, and, as she was considered suitable
for making a Transatlantic crossing, extra petrol tanks were fitted
in the hull and a new type of outer cover was fitted with a view to
her making the Atlantic crossing. She made a 21 hour cruise over the
North of England and the South of Scotland at the end of May, 1919,
and subsequently went for a longer cruise over Denmark, the Baltic, and
the north coast of Germany, remaining in the air for 56 hours in spite
of very bad weather conditions. Finally, July 2nd was selected as the
starting date for the cross Atlantic flight; the vessel was commanded
by Major G. H. Scott, A.F.C., with Captain G. S. Greenland as first
officer, Second-Lieut. H. F. Luck as second officer, and Lieut. J. D.
Shotter as engineer officer. There were also on board Brig.-Gen. E. P.
Maitland, representing the Air Ministry, Major J. E. M. Pritchard,
representing the Admiralty, and Lieut.-Col. W. H. Hemsley of the Army
Aviation Department. In addition to eight tons of petrol, R.34 carried
a total number of 30 persons from East Fortune to Long Island, N.Y.
There being no shed in America capable of accommodating the airship,
she had to be moored in the open for refilling with fuel and gas, and
to make the return journey almost immediately.
[Illustration: The R 34 landing at Pulham St Mary on arrival from
America.]
Brig.-Gen. Maitland’s account of the flight, in itself a record as
interesting as valuable, divides the outward journey into two main
stages, the first from East Fortune to Trinity Bay, Newfoundland, a
distance of 2,050 sea miles, and the second and more difficult stage
to Mineola Field, Long Island, 1,080 sea miles. An easy journey was
experienced until Newfoundland was reached, but then storms and
electrical disturbances rendered it necessary to alter the course, in
consequence of which petrol began to run short. Head winds rendered the
shortage still more acute, and on Saturday, July 5th, a wireless signal
was sent out asking for destroyers to stand by to tow. However, after
an anxious night, R.34 landed safely at Mineola Field at 9.55 a.m.
on July 6th, having accomplished the journey in 108 hours 12 minutes.
She remained at Mineola until midnight of July 9th, when, although
it had been intended that a start should be made by daylight for
the benefit of New York spectators, an approaching storm caused
preparations to be advanced for immediate departure. She set out at
5.57 a.m. by British summer time, and flew over New York in the full
glare of hundreds of searchlights before heading out over the Atlantic.
A following wind assisted the return voyage, and on July 13th, at 7.57
a.m., R.34 anchored at Pulham, Norfolk, having made the return journey
in 75 hours 3 minutes, and proved the suitability of the dirigible
for Transatlantic commercial work. R.80, launched on July 19th, 1920,
afforded further proof, if this were needed.
It is to be noted that nearly all the disasters to airships have
been caused by launching and landing--the type is safe enough in
the air, under its own power, but its bulk renders it unwieldy for
ground handling. The German system of handling Zeppelins in and out
of their sheds is, so far, the best devised: this consists of heavy
trucks running on rails through the sheds and out at either end;
on descending, the trucks are run out, and the airship is securely
attached to them outside the shed; the trucks are then run back into
the shed, taking the airship with them, and preventing any possibility
of the wind driving the envelope against the side of the shed before it
is safely housed; the reverse process is adopted in launching, which is
thus rendered as simple as it is safe.
VI
THE AIRSHIP COMMERCIALLY
Prior to the war period, between the years 1910 and 1914, a German
undertaking called the Deutsche Luftfahrt Actien Gesellschaft conducted
a commercial Zeppelin service in which four airships known as the
Sachsan, Hansa, Victoria Louise, and Schwaben were used. During the
four years of its work, the company carried over 17,000 passengers,
and over 100,000 miles were flown without incurring one fatality and
with only minor and unavoidable accidents to the vessels composing
the service. Although a number of English notabilities made voyages
in these airships, the success of this only experiment in commercial
aerostation seems to have been forgotten since the war. There was
beyond doubt a military aim in this apparently peaceful use of Zeppelin
airships; it is past question now that all Germany’s mechanical
development in respect of land, sea, and air transport in the years
immediately preceding the war, was accomplished with the ulterior
aim of military conquest, but, at the same time, the running of this
service afforded proof of the possibility of establishing a dirigible
service for peaceful ends, and afforded proof too, of the value of the
dirigible as a vessel of purely commercial utility.
[Illustration: The ‘Bodensee’ German passenger balloon.]
In considering the possibility of a commercial dirigible service, it
is necessary always to bear in mind the disadvantages of first cost
and upkeep as compared with the aeroplane. The building of a modern
rigid is an exceedingly costly undertaking, and the provision of an
efficient supply of hydrogen gas to keep its compartments filled is a
very large item in upkeep of which the heavier-than-air machine goes
free. Yet the future of commercial aeronautics so far would seem to lie
with the dirigible where very long voyages are in question. No matter
how the aeroplane may be improved, the possibility of engine failure
always remains as a danger for work over water. In seaplane or flying
boat form, the danger is still present in a rough sea, though in the
American Transatlantic flight, N.C.3, taxi-ing 300 miles to the Azores
after having fallen to the water, proved that this danger is not so
acute as is generally assumed. Yet the multiple-engined rigid, as R.34
showed on her return voyage, may have part of her power plant put out
of action altogether and still complete her voyage very successfully,
which, in the case of mail carrying and services run strictly to time,
gives her an enormous advantage over the heavier-than-air machine.
‘For commercial purposes,’ General Sykes has remarked, ‘the airship
is eminently adapted for long distance journeys involving non-stop
flights. It has this inherent advantage over the aeroplane, that while
there appears to be a limit to the range of the aeroplane as at present
constructed, there is practically no limit whatever to that of the
airship, as this can be overcome by merely increasing the size. It thus
appears that for such journeys as crossing the Atlantic, or crossing
the Pacific from the west coast of America to Australia or Japan, the
airship will be peculiarly suitable. It having been conceded that the
scope of the airship is long distance travel, the only type which need
be considered for this purpose is the rigid. The rigid airship is still
in an embryonic state, but sufficient has already been accomplished
in this country, and more particularly in Germany, to show that with
increased capacity there is no reason why, within a few years’ time,
airships should not be built capable of completing the circuit of the
globe and of conveying sufficient passengers and merchandise to render
such an undertaking a paying proposition.’
The British R.38 class, embodying the latest improvements in airship
design outside Germany, gives a gross lift per airship of 85 tons and
a net lift of about 45 tons. The capacity of the gas bags is about two
and three-quarter million cubic feet, and, travelling at the rate of 45
miles per hour, the cruising range of the vessel is estimated at 8·8
days. Six engines, each of 350 horse-power, admit of an extreme speed
of 70 miles per hour if necessary.
The last word in German design is exemplified in the rigids L.70 and
L.71, together with the commercial airship ‘Bodensee.’ Previous to
the construction of these, the L.65 type is noteworthy as being the
first Zeppelin in which direct drive of the propeller was introduced,
together with an improved and lighter type of car. L.70, built in 1918
and destroyed by the British naval forces, had a speed of about 75
miles per hour; L.71 had a maximum speed of 72 miles per hour, a gas
bag capacity of 2,420,000 cubic feet, and a length of 743 feet, while
the total lift was 73 tons. Progress in design is best shown by the
progress in useful load; in the L.70 and L.71 class, this has been
increased to 58·3 per cent, while in the Bodensee it was even higher.
As was shown in R.34’s American flight, the main problem in connection
with the commercial use of dirigibles is that of mooring in the open.
The nearest to a solution of this problem, so far, consists in the
mast carrying a swivelling cap; this has been tried in the British
service with a non-rigid airship, which was attached to a mast in open
country in a gale of 52 miles an hour without the slightest damage to
the airship. In its commercial form, the mast would probably take the
form of a tower, at the top of which the cap would revolve so that
the airship should always face the wind, the tower being used for
embarkation and disembarkation of passengers and the provision of fuel
and gas. Such a system would render sheds unnecessary except in case of
repairs, and would enormously decrease the establishment charges of any
commercial airship.
All this, however, is hypothetical. Remains the airship of to-day,
developed far beyond the promise of five years ago, capable, as has
been proved by its achievements both in Britain and in Germany, of
undertaking practically any given voyage with success.
VII
KITE BALLOONS
As far back as the period of the Napoleonic wars, the balloon was given
a place in warfare, but up to the Franco-Prussian War of 1870–71 its
use was intermittent. The Federal forces made use of balloons to a
small extent in the American Civil War; they came to great prominence
in the siege of Paris, carrying out upwards of three million letters
and sundry carrier pigeons which took back messages into the besieged
city. Meanwhile, as captive balloons, the German and other armies
used them for observation and the direction of artillery fire. In
this work the ordinary spherical balloon was at a grave disadvantage;
if a gust of wind struck it, the balloon was blown downward and down
wind, generally twirling in the air and upsetting any calculations
and estimates that might be made by the observers, while in a wind
of 25 miles an hour it could not rise at all. The rotatory movement
caused by wind was stopped by an experimenter in the Russo-Japanese
war, who fixed to the captive observation balloons a fin which acted
as a rudder. This did not stop the balloon from being blown downward
and away from its mooring station, but this tendency was overcome by a
modification designed in Germany by the Parseval-Siegsfield Company,
which originated what has since become familiar as the ‘Sausage’
or kite balloon. This is so arranged that the forward end is
tilted up into the wind, and the underside of the gas bag, acting
as a plane, gives the balloon a lifting tendency in a wind, thus
counteracting the tendency of the wind to blow it downward and away
from its mooring station. Smaller bags are fitted at the lower and rear
end of the balloon with openings that face into the wind; these are
thus kept inflated, and they serve the purpose of a rudder, keeping the
kite balloon steady in the air.
[Illustration: An early type of the Parseval-Siegsfeld observation
balloon.
Used by the Germans in Russia.]
[Illustration: An observation balloon about to ascend to watch enemy
movements, near Metz, 25th January, 1918.]
Various types of kite balloon have been introduced; the original German
Parseval-Siegsfield had a single air bag at the stern end, which was
modified to two, three, or more lobes in later varieties, while an
American experimental design attempted to do away with the attached
lobes altogether by stringing out a series of small air bags, kite
fashion, in rear of the main envelope. At the beginning of the War,
Germany alone had kite balloons, for the authorities of the Allied
armies considered that the bulk of such a vessel rendered it too
conspicuous a mark to permit of its being serviceable. The Belgian
arm alone possessed two which, on being put into service, were found
extremely useful. The French followed by constructing kite balloons at
Chalais Meudon, and then, after some months of hostilities and with the
example of the Royal Naval Air Service to encourage them, the British
military authorities finally took up the construction and use of kite
balloons for artillery-spotting and general observation purposes.
Although many were brought down by gun-fire, their uses far outweighed
their disadvantages, and toward the end of the War, hardly a mile of
front was without its ‘Sausage.’
For naval work, kite balloons were carried in a specially constructed
hold in the forepart of certain vessels; when required for use, the
covering of the hold was removed, the kite balloon inflated and
released to the required height by means of winches as in the case
of the land work. The perfecting of the ‘Coastal’ and N.S. types of
airship, together with the extension of wireless telephony between
airship and cruiser or other warship, in all probability will render
the use of the kite balloon unnecessary in connection with naval
scouting. But, during the War, neither wireless telephony nor naval
airships had developed sufficiently to render the Navy independent of
any means that might come to hand, and the fitting of kite balloons in
this fashion filled a need of the times.
A necessary accessory of the kite balloon is the parachute, which has a
long history. Da Vinci and Veranzio (_ante_, page 119) appear to have
been the first exponents, the first in the theory and the latter in the
practice of parachuting. Mongolfier experimented at Annonay before he
constructed his first hot air-balloon, and in 1783 a certain Lenormand
dropped from a tree in a parachute. Blanchard the balloonist made a
spectacle of parachuting, and made it a financial success; Cocking,
in 1836, attempted to use an inverted form of parachute; taken up to
a height of 3,000 feet, he was cut adrift, when the framework of the
parachute collapsed and Cocking was killed.
[Illustration: In mid-air. A parachute descent from one of our balloons
at the front, near Metz, 26th January, 1918.]
The rate of fall is slow in parachuting to the ground. Frau Poitevin,
making a descent from a height of 6,000 feet, took 45 minutes to reach
the ground, and, when she alighted, her husband, who had taken her up,
had nearly got his balloon packed up. Robertson, another parachutist,
is said to have descended from a height of 10,000 feet in 35
minutes, or at a rate of nearly 5 feet per second. During the War
Brigadier-General Maitland made a parachute descent from a height of
10,000 feet, the time taken being about 20 minutes.
The parachute was developed considerably during the War period, the
main requirement, that of certainty in opening, being considerably
developed. Considered a necessary accessory for kite balloons, the
parachute was also partially adopted for use with aeroplanes in the
later War period, when it was contended that if a machine were shot
down in flames, its occupants would be given a far better chance of
escape if they had parachutes. Various trials were made to demonstrate
the extreme efficiency of the parachute in modern form, one of them
being a descent from the upper ways of the Tower Bridge to the waters
of the Thames, in which short distance the ‘Guardian Angel’ type of
parachute opened and cushioned the descent for its user.
For dirigibles, balloons, and kite balloons the parachute is an
essential. It would seem to be equally essential in the case of
heavier-than-air machines, but this point is still debated. Certainly
it affords the occupant of a falling aeroplane a chance, no matter how
slender, of reaching the ground in safety, and, for that reason, it
would seem to have a place in aviation as well as in aerostation.
PART IV
ENGINE DEVELOPMENT
I
THE VERTICAL TYPE
The balloon was but a year old when the brothers Robert, in 1784,
attempted propulsion of an aerial vehicle by hand-power, and succeeded,
to a certain extent, since they were able to make progress when there
was only a slight wind to counteract their work. But, as may be easily
understood, the manual power provided gave but a very slow speed, and
in any wind at all the would-be airship became an uncontrolled balloon.
Henson and Stringfellow, with their light steam engines, were first
to attempt conquest of the problem of mechanical propulsion in the
air; their work in this direction is so fully linked up with their
constructed models that it has been outlined in the section dealing
with the development of the aeroplane (_ante_, page 57). But, very
shortly after these two began, there came into the field a Monsieur
Henri Giffard, who first achieved success in the propulsion by
mechanical means of dirigible balloons, for his was the first airship
to fly against the wind. He employed a small steam-engine developing
about 3 horse-power and weighing 350 lbs. with boiler, fitting the
whole in a car suspended from the gas-bag of his dirigible. The
propeller which this engine worked was 11 feet in diameter, and the
inventor, who made several flights, obtained a speed of 6 miles an
hour against a slight wind. The power was not sufficient to render the
invention practicable, as the dirigible could only be used in calm
weather, but Giffard was sufficiently encouraged by his results to get
out plans for immense dirigibles, which through lack of funds he was
unable to construct. When, later, his invention of the steam-injector
gave him the means he desired, he became blind, and in 1882 died,
having built but the one famous dirigible.
This appears to have been the only instance of a steam engine being
fitted to a dirigible; the inherent disadvantage of this form of motive
power is that a boiler to generate the steam must be carried, and this,
together with the weight of water and fuel, renders the steam engine
uneconomical in relation to the lift either of plane or gas-bag. Again,
even if the weight could be brought down to a reasonable amount, the
attention required by steam plant renders it undesirable as a motive
power for aircraft when compared with the internal combustion engine.
Maxim, in _Artificial and Natural Flight_, details the engine which
he constructed for use with his giant experimental flying machine,
and his description is worthy of reproduction since it is that of the
only steam engine besides Giffard’s, and apart from those used for the
propulsion of models, designed for driving an aeroplane. ‘In 1889,’
Maxim says, ‘I had my attention drawn to some very thin, strong, and
comparatively cheap tubes which were being made in France, and it
was only after I had seen these tubes that I seriously considered
the question of making a flying machine. I obtained a large quantity
of them and found that they were very light, that they would stand
enormously high pressures, and generate a very large quantity of
steam. Upon going into a mathematical calculation of the whole subject,
I found that it would be possible to make a machine on the aeroplane
system, driven by a steam engine, which would be sufficiently strong
to lift itself into the air. I first made drawings of a steam engine,
and a pair of these engines was afterwards made. These engines are
constructed, for the most part, of a very high grade of cast steel, the
cylinders being only 3/32 of an inch thick, the crank shafts hollow,
and every part as strong and light as possible. They are compound,
each having a high-pressure piston with an area of 20 square inches,
a low-pressure piston of 50.26 square inches, and a common stroke of
1 foot. When first finished they were found to weigh 300 lbs. each;
but after putting on the oil cups, felting, painting, and making some
slight alterations, the weight was brought up to 320 lbs. each, or a
total of 640 lbs. for the two engines, which have since developed 362
horse-power with a steam pressure of 320 lbs. per square inch.’
The result is remarkable, being less than 2 lbs. weight per
horse-power, especially when one considers the state of development
to which the steam engine had attained at the time these experiments
were made. The fining down of the internal combustion engine, which
has done so much to solve the problems of power in relation to weight
for use with aircraft, had not then been begun, and Maxim had nothing
to guide him, so far as work on the part of his predecessors was
concerned, save the experimental engines of Stringfellow, which, being
constructed on so small a scale in comparison with his own, afforded
little guidance. Concerning the factor of power, he says: ‘When first
designing this engine, I did not know how much power I might require
from it. I thought that in some cases it might be necessary to allow
the high-pressure steam to enter the low-pressure cylinder direct, but
as this would involve a considerable loss, I constructed a species of
injector. This injector may be so adjusted that when the steam in the
boiler rises above a certain predetermined point, say 300 lbs., to
the square inch, it opens a valve and escapes past the high-pressure
cylinder instead of blowing off at the safety valve. In escaping
through this valve, a fall of about 200 lbs. pressure per square inch
is made to do work on the surrounding steam and drive it forward in
the pipe, producing a pressure on the low-pressure piston considerably
higher than the back-pressure on the high-pressure piston. In this way
a portion of the work which would otherwise be lost is utilised, and it
is possible, with an unlimited supply of steam, to cause the engines to
develop an enormous amount of power.’
* * * * *
With regard to boilers, Maxim writes,--
‘The first boiler which I made was constructed something on the
Herreshof principle, but instead of having one simple pipe in one
very long coil, I used a series of very small and light pipes,
connected in such a manner that there was a rapid circulation
through the whole--the tubes increasing in size and number as the
steam was generated. I intended that there should be a pressure of
about 100 lbs. more on the feed-water end of the series than on the
steam end, and I believed that this difference in pressure would
be sufficient to ensure a direct and positive circulation through
every tube in the series. The first boiler was exceedingly light,
but the workmanship, as far as putting the tubes together was
concerned, was very bad, and it was found impossible to so adjust
the supply of water as to make dry steam without overheating and
destroying the tubes.
‘Before making another boiler I obtained a quantity of copper
tubes, about 8 feet long, ⅜ inch external diameter, and 1/50 of an
inch thick. I subjected about 100 of these tubes to an internal
pressure of 1 ton per square inch of cold kerosene oil, and as
none of them leaked I did not test any more, but commenced my
experiments by placing some of them in a white-hot petroleum fire.
I found that I could evaporate as much as 26½ lbs. of water per
square foot of heating surface per hour, and that with a forced
circulation, although the quantity of water passing was very small
but positive, there was no danger of overheating. I conducted many
experiments with a pressure of over 400 lbs. per square inch,
but none of the tubes failed. I then mounted a single tube in a
white-hot furnace, also with a water circulation, and found that
it only burst under steam at a pressure of 1,650 lbs. per square
inch. A large boiler, having about 800 square feet of heating
surface, including the feed-water heater, was then constructed.
This boiler is about 4½ feet wide at the bottom, 8 feet long and
6 feet high. It weighs, with the casing, the dome, and the smoke
stack and connections, a little less than 1,000 lbs. The water
first passes through a system of small tubes--¼ inch in diameter
and 1/60 inch thick--which were placed at the top of the boiler
and immediately over the large tubes.... This feed-water heater is
found to be very effective. It utilises the heat of the products
of combustion after they have passed through the boiler proper and
greatly reduces their temperature, while the feed-water enters the
boiler at a temperature of about 250 F. A forced circulation is
maintained in the boiler, the feed-water entering through a spring
valve, the spring valve being adjusted in such a manner that the
pressure on the water is always 30 lbs. per square inch in excess
of the boiler pressure. This fall of 30 lbs. in pressure acts upon
the surrounding hot water which has already passed through the
tubes, and drives it down through a vertical outside tube, thus
ensuring a positive and rapid circulation through all the tubes.
This apparatus is found to act extremely well.’
Thus Maxim, who with this engine as power for his large aeroplane
achieved free flight once, as a matter of experiment, though for what
distance or time the machine was actually off the ground is matter for
debate, since it only got free by tearing up the rails which were to
have held it down in the experiment. Here, however, was a steam engine
which was practicable for use in the air, obviously, and only the rapid
success of the internal combustion engine prevented the steam-producing
type from being developed toward perfection.
The first designers of internal combustion engines, knowing nothing
of the petrol of these days, constructed their examples with a view
to using gas as fuel. As far back as 1872 Herr Paul Haenlein obtained
a speed of about 10 miles an hour with a balloon propelled by an
internal combustion engine, of which the fuel was gas obtained from
the balloon itself. The engine in this case was of the Lenoir type,
developing some 6 horse-power, and, obviously, Haenlein’s flights were
purely experimental and of short duration, since he used the gas that
sustained him and decreased the lifting power of his balloon with every
stroke of the piston of his engine. No further progress appears to have
been made with the gas-consuming type of internal combustion engine for
work with aircraft; this type has the disadvantage of requiring either
a gas-producer or a large storage capacity for the gas, either of which
makes the total weight of the power plant much greater than that of
a petrol engine. The latter type also requires less attention when
working, and the fuel is more convenient both for carrying and in the
matter of carburation.
The first airship propelled by the present-day type of internal
combustion engine was constructed by Baumgarten and Wolfert in 1879
at Leipzig, the engine being made by Daimler with a view to working
on benzine--petrol as a fuel had not then come to its own. The
construction of this engine is interesting since it was one of the
first of Daimler’s make, and it was the development brought about
by the experimental series of which this engine was one that led to
the success of the motor-car in very few years, incidentally leading
to that fining down of the internal combustion engine which has
facilitated the development of the aeroplane with such remarkable
rapidity. Owing to the faulty construction of the airship no useful
information was obtained from Daimler’s pioneer installation, as the
vessel got out of control immediately after it was first launched for
flight, and was wrecked. Subsequent attempts at mechanically-propelled
flight by Wolfert ended, in 1897, in the balloon being set on fire by
an explosion of benzine vapour, resulting in the death of both the
aeronauts.
Daimler, from 1882 onward, devoted his attention to the perfecting of
the small, high-speed petrol engine for motor-car work, and owing to
his efforts, together with those of other pioneer engine-builders, the
motor-car was made a success. In a few years the weight of this type
of engine was reduced from near on a hundred pounds per horse-power to
less than a tenth of that weight, but considerable further improvement
had to be made before an engine suitable for use with aircraft was
evolved.
The increase in power of the engines fitted to airships has made
steady progress from the outset; Haenlein’s engine developed about
6 horse-power; the Santos-Dumont airship of 1898 was propelled by a
motor of 4 horse-power; in 1902 the Lebaudy airship was fitted with an
engine of 40 horse-power, while, in 1910, the Lebaudy brothers fitted
an engine of nearly 300 horse-power to the airship they were then
constructing--1,400 horse-power was common in the airships of the War
period, and the later British rigids developed yet more.
Before passing on to consideration of the petrol-driven type of engine,
it is necessary to accord brief mention to the dirigible constructed
in 1884 by Gaston and Albert Tissandier, who at Grenelle, France,
achieved a directed flight in a wind of 8 miles an hour, obtaining
their power for the propeller from 1⅓ horse-power Siemens electric
motor, which weighed 121 lbs. and took its current from a bichromate
battery weighing 496 lbs. A two-bladed propeller, 9 feet in diameter,
was used, and the horse-power output was estimated to have run up to
1½ as the dirigible successfully described a semicircle in a wind of 8
miles an hour, subsequently making headway transversely to a wind of 7
miles an hour. The dirigible with which this motor was used was of the
conventional pointed-end type, with a length of 92 feet, diameter of
30 feet, and capacity of 37.440 cubic feet of gas. Commandant Renard,
of the French army balloon corps, followed up Tissandier’s attempt in
the next year--1885--making a trip from Chalais-Meudon to Paris and
returning to the point of departure quite successfully. In this case
the motive power was derived from an electric plant of the type used
by the Tissandiers, weighing altogether 1,174 lbs., and developing
9 horse-power. A speed of 14 miles an hour was attained with this
dirigible, which had a length of 165 feet, diameter of 27 feet, and
capacity of 65,836 cubic feet of gas.
Reverting to the petrol-fed type again, it is to be noted that
Santos-Dumont was practically the first to develop the use of the
ordinary automobile engine for air work--his work is of such importance
that it has been considered best to treat of it as one whole, and
details of the power plants are included in the account of his
experiments. Coming to the Lebaudy brothers and their work, their
engine of 1902 was a 40 horse-power Daimler, four-cylindered; it was
virtually a large edition of the Daimler car engine, the arrangement of
the various details being on the lines usually adopted for the standard
Daimler type of that period. The cylinders were fully water-jacketed,
and no special attempt toward securing lightness for air-work appears
to have been made.
The fining down of detail that brought weight to such limits as would
fit the engine for work with heavier-than-air craft appears to have
waited for the brothers Wright. Toward the end of 1903 they fitted
to their first practicable flying machine the engine which made the
historic first aeroplane flight; this engine developed 30 horse-power,
and weighed only about 7 lbs. per horse-power developed, its design and
workmanship being far ahead of any previous design in this respect,
with the exception of the remarkable engine, designed by Manly,
installed in Langley’s ill-fated aeroplane--or ‘aerodrome,’ as he
preferred to call it--tried in 1903.
The light weight of the Wright brothers’ engine did not necessitate
a high number of revolutions per minute to get the requisite power;
the speed was only 1,300 revolutions per minute, which, with a piston
stroke of 3.94 inches, was quite moderate. Four cylinders were used,
the cylinder diameter being 4.42 inches; the engine was of the
vertical type, arranged to drive two propellers at a rate of about 350
revolutions per minute, gearing being accomplished by means of chain
drive from crank-shaft end to propeller spindle.
The methods adopted by the Wrights for obtaining a light-weight engine
were of considerable interest, in view of the fact that the honour
of first achieving flight by means of the driven plane belongs to
them--unless Ader actually flew as he claimed. The cylinders of this
first Wright engine were separate castings of steel, and only the
barrels were jacketed, this being done by fixing loose, thin aluminium
covers round the outside of each cylinder. The combustion head and
valve pockets were cast together with the cylinder barrel, and were not
water cooled. The inlet valves were of the automatic type, arranged on
the tops of the cylinders, while the exhaust valves were also overhead,
operated by rockers and push-rods. The pistons and piston rings were
of the ordinary type, made of cast-iron, and the connecting rods were
circular in form, with a hole drilled down the middle of each to reduce
the weight.
Necessity for increasing power and ever lighter weight in relation to
the power produced has led to the evolution of a number of different
designs of internal combustion engines. It was quickly realised that
increasing the number of cylinders on an engine was a better way of
getting more power than that of increasing the cylinder diameter, as
the greater number of cylinders gives better torque--even turning
effect--as well as keeping down the weight--this latter because the
bigger cylinders must be more stoutly constructed than the small sizes;
this fact has led to the construction of engines having as many as
eighteen cylinders, arranged in three parallel rows in order to keep
the length of crank-shaft within reasonable limits. The aero engine
of to-day may, roughly, be divided into four classes: these are the
V type, in which two rows of cylinders are set parallel at a certain
angle to each other; the radial type, which consists of cylinders
arranged radially and remaining stationary while the crankshaft
revolves; the rotary, where the cylinders are disposed round a common
centre and revolve round a stationary shaft, and the vertical type,
of four or six cylinders--seldom more than this--arranged in one row.
A modification of the V type is the eighteen-cylindered engine--the
Sunbeam is one of the best examples--in which three rows of cylinders
are set parallel to each other, working on a common crankshaft. The
development of these four types started with that of the vertical--the
simplest of all; the V, radial, and rotary types came after the
vertical, in the order given.
The evolution of the motor-car led to the adoption of the vertical
type of internal combustion engine in preference to any other, and
it followed naturally that vertical engines should be first used for
aeroplane propulsion, as by taking an engine that had been developed to
some extent, and adapting it to its new work, the problem of mechanical
flight was rendered easier than if a totally new type had had to be
evolved. It was quickly realised--by the Wrights, in fact--that the
minimum of weight per horse-power was the prime requirement for the
successful development of heavier-than-air machines, and at the same
time it was equally apparent that the utmost reliability had to be
obtained from the engine, while a third requisite was economy, in order
to reduce the weight of petrol necessary for flight.
[Illustration: Two Cylinder Daimler Engine, 1897.]
Daimler, working steadily toward the improvement of the internal
combustion engine, had made considerable progress by the end of
last century. His two-cylinder engine of 1897 was approaching to
the present-day type, except as regards the method of ignition; the
cylinders had 3.55 inch diameter, with a 4.75 inch piston stroke, and
the engine was rated at 4.5 brake horse-power, though it probably
developed more than this in actual running at its rated speed of 800
revolutions per minute. Power was limited by the inlet and exhaust
passages, which, compared with present-day practice, were very small.
The heavy castings of which the engine was made up are accounted for
by the necessity for considering foundry practice of the time, for in
1897 castings were far below the present-day standard. The crank-case
of this two-cylinder vertical Daimler engine was the only part made of
aluminium, and even with this no attempt was made to attain lightness,
for a circular flange was cast at the bottom to form a stand for
the engine during machining and erection. The general design can be
followed from the sectional views, and these will show, too, that
ignition was by means of a hot tube on the cylinder head, which had
to be heated with a blow-lamp before starting the engine. With all
its well known and hated troubles, at that time tube ignition had an
advantage over the magneto, and the coil and accumulator system, in
reliability; sparking plugs, too, were not so reliable then as they are
now. Daimler fitted a very simple type of carburettor to this engine,
consisting only of a float with a single jet placed in the air passage.
It may be said that this twin-cylindered vertical was the first of the
series from which has been evolved the Mercedes-Daimler car and airship
engines, built in sizes up to and even beyond 240 horse-power.
In 1901 the development of the petrol engine was still so slight that
it did not admit of the construction, by any European maker, of an
engine weighing less than 12 lbs. per horse-power. Manly, working
at the instance of Professor Langley, produced a five-cylindered
radial type engine, in which both the design and workmanship showed a
remarkable advance in construction. At 950 revolutions per minute it
developed 52.4 horse-power, weighing only 2.4 pounds per horse-power;
it was a very remarkable achievement in engine design, considering the
power developed in relation to the total weight, and it was, too, an
interruption in the development of the vertical type which showed that
there were other equally great possibilities in design.
In England, the first vertical aero engine of note was that designed
by Green, the cylinder dimensions being 4.15 inch diameter by 4.75
stroke--a fairly complete idea of this engine can be obtained from
the accompanying diagrams. At a speed of 1,160 revolutions per minute
it developed 35 brake horse-power, and by accelerating up to 1,220
revolutions per minute a maximum of 40 brake horse-power could be
obtained--the first-mentioned was the rated working speed of the engine
for continuous runs. A flywheel, weighing 23.5 lbs., was fitted to the
engine, and this, together with the ignition system, brought the weight
up to 188 lbs., giving 5.4 lbs. per horse-power. In comparison with the
engine fitted to the Wrights’ aeroplane a greater power was obtained
from approximately the same cylinder volume, and an appreciable
saving in weight had also been effected. The illustration shows the
arrangement of the vertical valves at the top of the cylinder and the
overhead cam shaft, while the position of the carburettor and inlet
pipes can be also seen. The water jackets were formed by thin copper
casings, each cylinder being separate and having its independent jacket
rigidly fastened to the cylinder at the top only, thus allowing for
free expansion of the casing; the joint at the bottom end was formed by
sliding the jacket over a rubber ring. Each cylinder was bolted to the
crank-case and set out of line with the crankshaft, so that the crank
has passed over the upper dead centre by the time that the piston is at
the top of its stroke when receiving the full force of fuel explosion.
The advantage of this _desaxe_ setting is that the pressure in the
cylinder acts on the crank-pin with a more effective leverage during
that part of the stroke when that pressure is highest, and in addition
the side pressure of the piston on the cylinder wall, due to the
thrust of the connecting rod, is reduced. Possibly the charging of the
cylinder is also more complete by this arrangement, owing to the slower
movement of the piston at the bottom of its stroke allowing time for an
increased charge of mixture to enter the cylinder.
A 60 horse-power engine was also made, having four vertical cylinders,
each with a diameter of 5.5 inches and stroke of 5.75 inches,
developing its rated power at 1,100 revolutions per minute. By
accelerating up to 1,200 revolutions per minute 70 brake horse-power
could be obtained, and a maximum of 80 brake horse-power was actually
attained with the type. The flywheel, fitted as with the original 35
horse-power engine, weighed 37 lbs.; with this and with the ignition
system the total weight of the engine was only 250 lbs., or 4.2 lbs.
per horse-power at the normal rating. In this design, however, low
weight in relation to power was not the ruling factor, for Green gave
more attention to reliability and economy of fuel consumption, which
latter was approximately 0.6 pint of petrol per brake horse-power per
hour. Both the oil for lubricating the bearings and the water for
cooling the cylinders were circulated by pumps, and all parts of the
valve gear, etc., were completely enclosed for protection from dust.
[Illustration: Green Vertical Engine 35 b. h. p.]
A later development of the Green engine was a six-cylindered vertical,
cylinder dimensions being 5.5 inch diameter by 6 inch stroke,
developing 120 brake horse-power when running at 1,250 revolutions
per minute. The total weight of the engine with ignition system was
440 lbs., or 3.66 lbs. per horse-power. One of these engines was used
on the machine which, in 1909, won the prize of £ 1,000 for the first
circular mile flight, and it may be noted, too, that S. F. Cody, making
the circuit of England in 1911, used a four-cylinder Green engine.
Again, it was a Green engine that in 1914 won the £5,000 prize offered
for the best aero engine in the Naval and Military aeroplane engine
competition.
Manufacture of the Green engines, in the period of the War, had
standardised to the production of three types. Two of these were
six-cylinder models, giving respectively 100 and 150 brake horse-power,
and the third was a twelve-cylindered model rated at 275 brake
horse-power.
In 1910 J. S. Critchley compiled a list showing the types of engine
then being manufactured; twenty-two out of a total of seventy-six were
of the four-cylindered vertical type, and in addition to these there
were two six-cylindered verticals. The sizes of the four-cylinder types
ranged from 26 up to 118 brake horse-power; fourteen of them developed
less than 50 horse-power, and only two developed over 100 horse-power.
It became apparent, even in the early stages of heavier-than-air
flying, that four-cylinder engines did not produce the even torque
that was required for the rotation of the power shaft, even though
a flywheel was fitted to the engine. With this type of engine the
breakage of air-screws was of frequent occurrence, and an engine having
a more regular rotation was sought, both for this and to avoid the
excessive vibration often experienced with the four-cylinder type.
Another point that forced itself on engine builders was that the
increased power which was becoming necessary for the propulsion of
aircraft made an increase in the number of cylinders essential, in
order to obtain a light engine. An instance of the weight reduction
obtainable in using six cylinders instead of four is shown in
Critchley’s list, for one of the four-cylinder engines developed 118.5
brake horse-power and weighed 1,100 lbs., whereas a six-cylinder
engine by the same manufacturer developed 117.5 brake horse-power with
a weight of 880 lbs., the respective cylinder dimensions being 7.48
diameter by 9.06 stroke for the four-cylinder engine, and 6.1 diameter
by 7.28 stroke for the six-cylinder type.
A list of aeroplane engines, prepared in 1912 by Graham Clark, showed
that, out of the total number of 112 engines then being manufactured,
forty-two were of the vertical type, and of this number twenty-four
had four-cylinders while sixteen were six-cylindered. The German
aeroplane engine trials were held a year later, and sixty-six engines
entered the competition, fourteen of these being made with air-cooled
cylinders. All of the ten engines that were chosen for the final trials
were of the water-cooled type, and the first place was won by a Benz
four-cylinder vertical engine which developed 102 brake horse-power at
1,288 revolutions per minute. The cylinder dimensions of this engine
were 5.1 inch diameter by 7.1 inch stroke, and the weight of the engine
worked out at 3.4 lbs. per brake horse-power. During the trials the
full-load petrol consumption was 0.53 pint per horse-power per hour,
and the amount of lubricating oil used was 0.0385 pint per brake
horse-power per hour. In general construction this Benz engine was
somewhat similar to the Green engine already described; the overhead
valves, fitted in the tops of the cylinders, were similarly arranged,
as was the cam-shaft; two springs were fitted to each of the valves to
guard against the possibility of the engine being put out of action
by breakage of one of the springs, and ignition was obtained by two
high-tension magnetos giving simultaneous sparks in each cylinder
by means of two sparking plugs--this dual ignition reduced the
possibility of ignition troubles. The cylinder jackets were made of
welded sheet steel so fitted around the cylinder that the head was also
water-cooled, and the jackets were corrugated in the middle to admit
of independent expansion. Even the lubrication system was duplicated,
two sets of pumps being used, one to circulate the main supply of
lubricating oil, and the other to give a continuous supply of fresh oil
to the bearings, so that if the supply from one pump failed the other
could still maintain effective lubrication.
Development of the early Daimler type brought about the four-cylinder
vertical Mercedes-Daimler engine of 85 horse-power, with cylinders
of 5.5 diameter with 5.9 inch stroke, the cylinders being cast in
two pairs. The overhead arrangement of valves was adopted, and in
later designs push-rods were eliminated, the overhead cam-shaft being
adopted in their place. By 1914 the four-cylinder Mercedes-Daimler
had been partially displaced from favour by a six-cylindered model,
made in two sizes; the first of these gave a nominal brake horse-power
of 80, having cylinders of 4.1 inches diameter by 5.5 inches stroke;
the second type developed 100 horse-power with cylinders 4.7 inches
in diameter and 5.5 inches stroke, both types being run at 1,200
revolutions per minute. The cylinders of both these types were cast in
pairs, and, instead of the water jackets forming part of the casting,
as in the design of the original four-cylinder Mercedes-Daimler engine,
they were made of steel welded to flanges on the cylinders. Steel
pistons, fitted with cast-iron rings, were used, and the overhead
arrangement of valves and cam-shaft was adopted. About 0.55 pint per
brake horse-power per hour was the usual fuel consumption necessary to
full load running, and the engine was also economical as regards the
consumption of lubricating oil, the lubricating system being ‘forced’
for all parts, including the cam-shaft. The shape of these engines was
very well suited for work with aircraft, being narrow enough to admit
of a stream-line form being obtained, while all the accessories could
be so mounted as to produce little or no wind resistance, and very
little obstruction to the pilot’s view.
The eight-cylinder Mercedes-Daimler engine, used for airship propulsion
during the War, developed 240 brake horse-power at 1,100 revolutions
per minute; the cylinder dimensions were 6.88 diameter by 6.5
stroke--one of the instances in which the short stroke in relation to
bore was very noticeable.
Other instances of successful vertical design--the types already
detailed are fully sufficient to give particulars of the type
generally--are the Panhard, Chenu, Maybach, N.A.G., Argus, Mulag, and
the well-known Austro-Daimler, which by 1917 was being copied in every
combatant country. There are also the later Wright engines, and in
America the Wisconsin six-cylinder vertical, weighing well under 4 lbs.
per horse-power, is evidence of the progress made with this first type
of aero engine to develop.
II
THE VEE TYPE
An offshoot from the vertical type, doubling the power of this with
only a very slight--if any--increase in the length of crankshaft, the
Vee or diagonal type of aero engine leaped to success through the
insistent demand for greater power. Although the design came after that
of the vertical engine, by 1910, according to Critchley’s list of aero
engines, there were more Vee type engines being made than any other
type, twenty-five sizes being given in the list, with an average rating
of 57·4 brake horse-power.
The arrangement of the cylinders in Vee form over the crankshaft,
enabling the pistons of each pair of opposite cylinders to act upon the
same crank pin, permits of a very short, compact engine being built,
and also permits of reduction of the weight per horse-power, comparing
this with that of the vertical type of engine, with one row of
cylinders. Further, at the introduction of this type of engine it was
seen that crankshaft vibration, an evil of the early vertical engines,
was practically eliminated, as was the want of longitudinal stiffness
that characterised the higher-powered vertical engines.
Of the Vee type engines shown in Critchley’s list in 1910, nineteen
different sizes were constructed with eight cylinders, and with
horse-powers ranging from thirty to just over the hundred; the
lightest of these weighed 2·9 lbs. per horse-power--a considerable
advance in design on the average vertical engine, in this respect of
weight per horse-power. There were also two sixteen-cylinder engines of
Vee design, the larger of which developed 134 horse-power with a weight
of only 2 lbs. per brake horse-power. Subsequent developments have
indicated that this type, with the further development from it of the
double-Vee, or engine with three rows of cylinders, is likely to become
the standard design of aero engine where high powers are required.
The construction permits of placing every part so that it is easy of
access, and the form of the engine implies very little head resistance,
while it can be placed on the machine--supposing that machine to be of
the single-engine type--in such a way that the view of the pilot is
very little obstructed while in flight.
An even torque, or great uniformity of rotation, is transmitted to
the air-screw by these engines, while the design also permits of
such good balance of the engine itself that vibration is practically
eliminated. The angle between the two rows of cylinders is varied
according to the number of cylinders, in order to give working impulses
at equal angles of rotation and thus provide even torque; this angle is
determined by dividing the number of degrees in a circle by the number
of cylinders in either row of the engine. In an eight-cylindered Vee
type engine, the angle between the cylinders is 90 degrees; if it is a
twelve-cylindered engine, the angle drops to 60 degrees.
One of the earliest of the British-built Vee type engines was an
eight-cylinder 50 horse-power by the Wolseley Company, constructed
in 1908 with a cylinder bore of 3·75 inches and stroke of 5 inches,
running at a normal speed of 1,350 revolutions per minute. With this
engine, a gearing was introduced to enable the propeller to run at a
lower speed than that of the engine, the slight loss of efficiency
caused by the friction of the gearing being compensated by the slower
speed of the air-screw, which had higher efficiency than would have
been the case if it had been run at the engine speed. The ratio of the
gearing--that is, the speed of the air-screw relatively to that of the
engine, could be chosen so as to suit exactly the requirements of the
air-screw, and the gearing itself, on this engine, was accomplished on
the half-speed shaft actuating the valves.
Very soon after this first design had been tried out, a second Vee type
engine was produced which, at 1,200 revolutions per minute, developed
60 horse-power; the size of this engine was practically identical with
that of its forerunner, the only exception being an increase of half an
inch in the cylinder stroke--a very long stroke of piston in relation
to the bore of the cylinder. In the first of these two engines, which
was designed for airship propulsion, the weight had been about 8 lbs.
per brake horse-power, no special attempt appearing to have been made
to fine down for extreme lightness; in this 60 horse-power design, the
weight was reduced to 6·1 lbs. per horse-power, counting the latter
as normally rated; the engine actually gave a maximum of 75 brake
horse-power, reducing the ratio of weight to power very considerably
below the figure given.
[Illustration: Sikh, 12-cylinder magneto, end view.]
[Illustration: Sikh, 12-cylinder, side view.]
The accompanying diagram illustrates a later Wolseley model, end
elevation, the eight-cylindered 120 horse-power Vee type aero engine
of the early war period. With this engine, each crank pin has two
connecting rods bearing on it, these being placed side by side and
connected to the pistons of opposite cylinders, and the two cylinders
of the pair are staggered by an amount equal to the width of the
connecting rod-bearing, to afford accommodation for the rods. The
crankshaft was a nickel chrome steel forging, machined hollow, with
four crank pins set at 180 degrees to each other, and carried in three
bearings lined with anti-friction metal. The connecting rods were made
of tubular nickel chrome steel, and the pistons of drawn steel, each
being fitted with four piston rings. Of these the two rings nearest
to the piston head were of the ordinary cast-iron type, while the
others were of phosphor bronze, so arranged as to take the side thrust
of the piston. The cylinders were of steel, arranged in two groups
or rows of four, the angular distance between them being 90 degrees.
In the space above the crankshaft, between the cylinder rows, was
placed the valve-operating mechanism, together with the carburettor
and ignition system, thus rendering this a very compact and accessible
engine. The combustion heads of the cylinders were made of cast-iron,
screwed into the steel cylinder barrels; the water-jacket was of spun
aluminium, with one end fitting over the combustion head and the other
free to slide on the cylinder; the water-joint at the lower end was
made tight by a Dermatine ring carried between small flanges formed
on the cylinder barrel. Overhead valves were adopted, and in order
to make these as large as possible the combustion chamber was made
slightly larger in diameter than the cylinder, and the valves set at an
angle. Dual ignition was fitted in each cylinder, coil and accumulator
being used for starting and as a reserve in case of failure of the
high-tension magneto system fitted for normal running. There was a
double set of lubricating pumps, ensuring continuity of the oil supply
to all the bearings of the engine.
[Illustration: End View of Wolseley 120 horse-power Vee-type Engine.]
The feature most noteworthy in connection with the running of this
type of engine was its flexibility; the normal output of power was
obtained with 1,150 revolutions per minute of the crankshaft, but,
by accelerating up to 1,400 revolutions, a maximum of 147 brake
horse-power could be obtained. The weight was about 5 lbs. per
horse-power, the cylinder dimensions being 5 inches bore by 7 inches
stroke. Economy in running was obtained, the fuel consumption being
0·58 pint per brake horse-power per hour at full load, with an
expenditure of about 0·075 pint lubricating oil per brake horse-power
per hour.
Another Wolseley Vee type that was standardised was a 90 horse-power
eight-cylinder engine running at 1,800 revolutions per minute, with a
reducing gear introduced by fitting the air-screw on the half-speed
shaft. First made semi-cooled--the exhaust valve was left air-cooled,
and then entirely water-jacketed--this engine demonstrated the
advantage of full water cooling, for under the latter condition the
same power was developed with cylinders a quarter of an inch less in
diameter than in the semi-cooled pattern; at the same time the weight
was brought down to 4½ lbs. per horse-power.
A different but equally efficient type of Vee design was the Dorman
engine, of which an end elevation is shown; this developed 80 brake
horse-power at a speed of 1,300 revolutions per minute, with a cylinder
bore of 5 inches; each cylinder was made in cast-iron in one piece with
the combustion chamber, the barrel only being water-jacketed. Auxiliary
exhaust ports were adopted, the holes through the cylinder wall being
uncovered by the piston at the bottom of its stroke--the piston, 4·75
inches in length, was longer than its stroke, so that these ports were
covered when it was at the top of the cylinder. The exhaust discharged
through the ports into a belt surrounding the cylinder, the belts on
the cylinders being connected so that the exhaust gases were taken
through a single pipe. The air was drawn through the crank case, before
reaching the carburettor, this having the effect of cooling the oil
in the crank case as well as warming the air and thus assisting in
vaporising the petrol for each charge of the cylinders. The inlet and
exhaust valves were of the overhead type, as may be gathered from the
diagram, and in spite of cast-iron cylinders being employed a light
design was obtained, the total weight with radiator, piping, and water
being only 5·5 lbs. per horse-power.
[Illustration: Dorman 80 horse-power Vee-type Engine.]
Here was the antithesis of the Wolseley type in the matter of bore in
relation to stroke; from about 1907 up to the beginning of the war, and
even later, there was controversy as to which type--that in which the
bore exceeded the stroke, or _vice versa_--gave greater efficiency.
The short-stroke enthusiasts pointed to the high piston speed of the
long-stroke type, while those who favoured the latter design contended
that full power could not be obtained from each explosion in the
short-stroke type of cylinder. It is now generally conceded that the
long-stroke engine yields higher efficiency, and in addition to this,
so far as car engines are concerned, the method of rating horse-power
in relation to bore without taking stroke into account has given the
long-stroke engine an advantage, actual horse-power with a long stroke
engine being in excess of the nominal rating. This may have had some
influence on aero engine design, but, however this may have been, the
long-stroke engine has gradually come to favour, and its rival has
taken second place.
For some time pride of place among British Vee type engines was held
by the Sunbeam Company, which, owing to the genius of Louis Coatalen,
together with the very high standard of construction maintained by
the firm, achieved records and fame in the middle and later periods
of the war. Their 225 horse-power twelve-cylinder engine ran at a
normal speed of 2,000 revolutions per minute; the air-screw was driven
through gearing at half this speed, its shaft being separate from the
timing gear and carried in ball-bearings on the nose-piece of the
engine. The cylinders were of cast-iron, entirely water-cooled; a thin
casing formed the water-jacket, and a very light design was obtained,
the weight being only 3·2 lbs. per horse-power. The first engine of
Sunbeam design had eight cylinders and developed 150 horse-power at
2,000 revolutions per minute; the final type of Vee design produced
during the war was twelve-cylindered, and yielded 310 horse-power with
cylinders 4·3 inches bore by 6·4 inches stroke. Evidence in favour of
the long-stroke engine is afforded in this type as regards economy of
working; under full load, working at 2,000 revolutions per minute, the
consumption was 0·55 pints of fuel per brake horse-power per hour,
which seems to indicate that the long stroke permitted of full use
being made of the power resulting from each explosion, in spite of the
high rate of speed of the piston.
Developing from the Vee type, the eighteen-cylinder 475 brake
horse-power engine, designed during the war, represented for a time
the limit of power obtainable from a single plant. It was water-cooled
throughout, and the ignition to each cylinder was duplicated; this
engine proved fully efficient, and economical in fuel consumption. It
was largely used for seaplane work, where reliability was fully as
necessary as high power.
The abnormal needs of the war period brought many British firms into
the ranks of Vee-type engine-builders, and, apart from those mentioned,
the most notable types produced are the Rolls-Royce and the Napier.
The first mentioned of these firms, previous to 1914, had concentrated
entirely on car engines, and their very high standard of production in
this department of internal combustion engine work led, once they took
up the making of aero engines, to extreme efficiency both of design
and workmanship. The first experimental aero engine, of what became
known as the ‘Eagle’ type, was of Vee design--it was completed in March
of 1915--and was so successful that it was standardised for quantity
production. How far the original was from the perfection subsequently
ascertained is shown by the steady increase in developed horse-power
of the type; originally designed to develop 200 horse-power, it was
developed and improved before its first practical trial in October
of 1915, when it developed 255 horse-power on a brake test. Research
and experiment produced still further improvements, for, without any
enlargement of the dimensions, or radical alteration in design, the
power of the engine was brought up to 266 horse-power by March of
1916, the rate of revolutions of 1,800 per minute being maintained
throughout. July, 1916, gave 284 horse-power; by the end of the year
this had been increased to 322 horse-power; by September of 1917 the
increase was to 350 horse-power, and by February of 1918 the ‘Eagle’
type of engine was rated at 360 horse-power, at which standard it
stayed. But there is no more remarkable development in engine design
than this, a 75 per cent increase of power in the same engine in a
period of less than three years.
To meet the demand for a smaller type of engine for use on training
machines, the Rolls-Royce firm produced the ‘Hawk’ Vee-type engine of
100 horse-power, and, intermediately between this and the ‘Eagle,’
the ‘Falcon’ engine came to being with an original rated horse-power
of 205 at 1,800 revolutions per minute, in April of 1916. Here was
another case of growth of power in the same engine through research,
almost similar to that of the ‘Eagle’ type, for by July of 1918 the
‘Falcon’ was developing 285 horse-power with no radical alteration of
design. Finally, in response to the constant demand for increase of
power in a single plant, the Rolls-Royce company designed and produced
the ‘Condor’ type of engine, which yielded 600 horse-power on its first
test in August of 1918. The cessation of hostilities and consequent
falling off in the demand for extremely high-powered plants prevented
the ‘Condor’ being developed to its limit, as had been the ‘Falcon’ and
‘Eagle’ types.
The ‘Eagle’ engine was fitted to the two Handley-Page aeroplanes which
made flights from England to India--it was virtually standard on the
Handley-Page bombers of the later War period, though to a certain
extent the American ‘Liberty’ engine was also used. Its chief record,
however, is that of being the type fitted to the Vickers-Vimy aeroplane
which made the first Atlantic flight, covering the distance of 1,880
miles at a speed averaging 117 miles an hour.
The Napier Company specialised on one type of engine from the outset,
a power plant which became known as the ‘Lion’ engine, giving 450
horse-power with twelve cylinders arranged in three rows of four each.
Considering the engine as ‘dry,’ or without fuel and accessories, an
abnormally light weight per horse-power--only 1·89 lbs.--was attained
when running at the normal rate of revolution. The cylinders and
water-jackets are of steel, and there is fitted a detachable aluminium
cylinder head containing inlet and exhaust valves and valve actuating
mechanism; pistons are of aluminium alloy, and there are two inlet and
two exhaust valves to each cylinder, the whole of the valve mechanism
being enclosed in an oil-tight aluminium case. Connecting rods and
crankshaft are of steel, the latter being machined from a solid steel
forging and carried in five roller bearings and one plain bearing at
the forward end. The front end of the crank-case encloses reduction
gear for the propeller shaft, together with the shaft and bearings.
There are two suction and one pressure type oil pumps driven through
gears at half-engine speed, and two 12 spark magnetos, giving 2 sparks
in each cylinder.
The cylinders are set with the central row vertical, and the two side
rows at angles of 60 degrees each; cylinder bore is 5½ inches, and
stroke 5⅛ inches; the normal rate of revolution is 1,350 per minute,
and the reducing gear gives one revolution of the propeller shaft to
1·52 revolutions of crankshaft. Fuel consumption is 0·48 lbs. of
fuel per brake horse-power hour at full load, and oil consumption is
0·020 lbs. per brake horse-power hour. The dry weight of the engine,
complete with propeller boss, carburettors, and induction pipes, is 850
lbs., and the gross weight in running order, with fuel and oil for six
hours working, is 2,671 lbs., exclusive of cooling water.
[Illustration: Napier ‘Lion.’]
[Illustration: Napier ‘Lion.’]
To this engine belongs an altitude record of 30,500 feet, made at
Martlesham, near Ipswich, on January 2nd, 1919, by Captain Lang,
R.A.F., the climb being accomplished in 66 minutes 15 seconds. Previous
to this, the altitude record was held by an Italian pilot, who made
25,800 feet in an hour and 57 minutes in 1916. Lang’s climb was
stopped through the pressure of air, at the altitude he reached, being
insufficient for driving the small propellers on the machine which
worked the petrol and oil pumps, or he might have made the height said
to have been attained by Major Schroeder on February 27th, 1920, at
Dayton, Ohio. Schroeder is said to have reached an altitude of 36,020
feet on a Napier biplane, and, owing to failure of the oxygen supply,
to have lost consciousness, fallen five miles, righted his machine when
2,000 feet in the air, and alighted successfully. Major Schroeder is an
American.
Turning back a little, and considering other than British design of Vee
and double-Vee or ‘Broad arrow’ type of engine, the Renault firm from
the earliest days devoted considerable attention to the development
of this type, their air-cooled engines having been notable examples
from the earliest days of heavier-than-air machines. In 1910 they were
making three sizes of eight-cylindered Vee-type engines, and by 1915
they had increased to the manufacture of five sizes, ranging from
25 to 100 brake horse-power, the largest of the five sizes having
twelve cylinders but still retaining the air-cooled principle. The
De Dion firm, also, made Vee-type engines in 1914, being represented
by an 80 horse-power eight-cylindered engine, air-cooled, and a 150
horse-power, also of eight cylinders, water-cooled, running at a
normal rate of 1,600 revolutions per minute. Another notable example
of French construction was the Panhard and Levassor 100 horse-power
eight-cylinder Vee engine, developing its rated power at 1,500
revolutions per minute, and having the--for that time--low weight of
4·4 lbs. per horse-power.
American Vee design has followed the British fairly closely; the
Curtiss Company produced originally a 75 horse-power eight-cylinder Vee
type running at 1,200 revolutions per minute, supplementing this with
a 170 horse-power engine running at 1,600 revolutions per minute, and
later with a twelve-cylinder model Vee type, developing 300 horse-power
at 1,500 revolutions per minute, with cylinder bore of 5 inches and
stroke of 7 inches. An exceptional type of American design was the Kemp
Vee engine of 80 horse-power, in which the cylinders were cooled by a
current of air obtained from a fan at the forward end of the engine.
With cylinders of 4·25 inches bore and 4·75 inches stroke, the rated
power was developed at 1,150 revolutions per minute, and with the
engine complete the weight was only 4·75 lbs. per horse-power.
III
THE RADIAL TYPE
The very first successful design of internal combustion aero engine
made was that of Charles Manly, who built a five-cylinder radial engine
in 1901 for use with Langley’s ‘aerodrome,’ as the latter inventor
decided to call what has since become known as the aeroplane. Manly
made a number of experiments, and finally decided on radial design, in
which the cylinders are so rayed round a central crank-pin that the
pistons act successively upon it; by this arrangement a very short and
compact engine is obtained, with a minimum of weight, and a regular
crankshaft rotation and perfect balance of inertia forces.
When Manly designed his radial engine, high-speed internal combustion
engines were in their infancy, and the difficulties in construction
can be partly realised when the lack of manufacturing methods for
this high-class engine work, and the lack of experimental data on the
various materials, are taken into account. During its tests, Manly’s
engine developed 52·4 brake horse-power at a speed of 950 revolutions
per minute, with the remarkably low weight of only 2·4 lbs. per
horse-power; this latter was increased to 3·6 lbs. when the engine was
completed by the addition of ignition system, radiator, petrol tank,
and all accessories, together with the cooling water for the cylinders.
[Illustration: Cross Section, Manly’s 5 Cylinder Radial Engine.]
In Manly’s engine the cylinders were of steel, machined outside and
inside to 1/16 of an inch thickness; on the side of the cylinder, at
the top end, the valve chamber was brazed, being machined from a solid
forging. The casing which formed the water-jacket was of sheet steel,
1/50 of an inch in thickness, and this also was brazed on the cylinder
and to the valve chamber. Automatic inlet valves were fitted, and
the exhaust valves were operated by a cam which had two points, 180
degrees apart; the cam was rotated in the opposite direction to the
engine at one-quarter engine speed. Ignition was obtained by using
a one-spark coil and vibrator for all cylinders, with a distributor
to select the right cylinder for each spark--this was before the days
of the high-tension magneto and the almost perfect ignition systems
that makers now employ. The scheme of ignition for this engine was
originated by Manly himself, and he also designed the sparking plugs
fitted in the tops of the cylinders. Through fear of trouble resulting
if the steel pistons worked on the steel cylinders, cast-iron liners
were introduced in the latter, 1/16 of an inch thick.
The connecting rods of this engine were of virtually the same type
as is employed on nearly all modern radial engines. The rod for one
cylinder had a bearing along the whole of the crank pin, and its end
enclosed the pin; the other four rods had bearings upon the end of the
first rod, and did not touch the crank pin. The accompanying diagram
shows this construction, together with the means employed for securing
the ends of the four rods--the collars were placed in position after
the rods had been put on. The bearings of these rods did not receive
any of the rubbing effect due to the rotation of the crank pin, the
rubbing on them being only that of the small angular displacement
of the rods during each revolution; thus there was no difficulty
experienced with the lubrication.
Another early example of the radial type of engine was the French
Anzani, of which type one was fitted to the machine with which Bleriot
first crossed the English Channel--this was of 25 horse-power. The
earliest Anzani engines were of the three-cylinder fan type, one
cylinder being vertical, and the other two placed at an angle of 72
degrees on each side, as the possibility of over-lubrication of the
bottom cylinders was feared if a regular radial construction were
adopted. In order to overcome the unequal balance of this type, balance
weights were fitted inside the crank case.
The final development of this three-cylinder radial was the ‘Y’ type of
engine, in which the cylinders were regularly disposed at 120 degrees
apart; the bore was 4·1, stroke 4·7 inches, and the power developed was
30 brake horse-power at 1,300 revolutions per minute.
Critchley’s list of aero engines being constructed in 1910 shows twelve
of the radial type, with powers of between 14 and 100 horse-power, and
with from three to ten cylinders--this last is probably the greatest
number of cylinders that can be successfully arranged in circular form.
Of the twelve types of 1910, only two were water-cooled, and it is to
be noted that these two ran at the slowest speeds and had the lowest
weight per horse-power of any.
The Anzani radial was considerably developed, special attention
being paid to this type by its makers, and by 1914 the Anzani list
comprised seven different sizes of air-cooled radials. Of these the
largest had twenty cylinders, developing 200 brake horse-power--it
was virtually a double radial--and the smallest was the original 30
horse-power three-cylinder design. A six-cylinder model was formed by
a combination of two groups of three cylinders each, acting upon a
double-throw crankshaft; the two crank pins were set at 180 degrees to
each other, and the cylinder groups were staggered by an amount equal
to the distance between the centres of the crank pins. Ten-cylinder
radial engines are made with two groups of five cylinders acting upon
two crank pins set at 180 degrees to each other; the largest Anzani
‘ten’ developed 125 horse-power at 1,200 revolutions per minute, the
ten cylinders being each 4·5 inches in bore with stroke of 5·9 inches,
and the weight of the engine being 3·7 lbs. per horse-power. In the 200
horse-power Anzani radial the cylinders are arranged in four groups
of five each, acting on two crank pins. The bore of the cylinders
in this engine is the same as in the three-cylinder, but the stroke
is increased to 5·5 inches. The rated power is developed at 1,300
revolutions per minute, and the engine complete weighs 3·4 lbs. per
horse-power.
With this 200 horse-power Anzani, a petrol consumption of as low as
0·49 lbs. of fuel per brake horse-power per hour has been obtained,
but the consumption of lubricating oil is compensatingly high, being
up to one-fifth of the fuel used. The cylinders are set _desaxé_ with
the crank shaft, and are of cast-iron, provided with radiating ribs
for air-cooling; they are attached to the crank case by long bolts
passing through bosses at the top of the cylinders, and connected to
other bolts at right angles through the crank case. The tops of the
cylinders are formed flat, and seats for the inlet and exhaust valves
are formed on them. The pistons are cast-iron, fitted with ordinary
cast-iron spring rings. An aluminium crank case is used, being made
in two halves connected together by bolts, which latter also attach
the engine to the frame of the machine. The crankshaft is of nickel
steel, made hollow, and mounted on ball-bearings in such a manner that
practically a combination of ball and plain bearings is obtained; the
central web of the shaft is bent to bring the centres of the crank pins
as close together as possible, leaving only room for the connecting
rods, and the pins are 180 degrees apart. Nickel steel valves of the
cone-seated, poppet type are fitted, the inlet valves being automatic,
and those for the exhaust cam-operated by means of push-rods. With an
engine having such a number of cylinders a very uniform rotation of the
crankshaft is obtained, and in actual running there are always five of
the cylinders giving impulses to the crankshaft at the same time.
An interesting type of pioneer radial engine was the Farcot, in which
the cylinders were arranged in a horizontal plane, with a vertical
crankshaft which operated the air-screw through bevel gearing. This
was an eight-cylinder engine, developing 64 horse-power at 1,200
revolutions per minute. The R.E.P. type, in the early days, was a ‘fan’
engine, but the designer, M. Robert Pelterie, turned from this design
to a seven-cylinder radial, which at 1,100 revolutions per minute gave
95 horse-power. Several makers entered into radial engine development
in the years immediately preceding the War, and in 1914 there were
some twenty-two different sizes and types, ranging from 30 to 600
horse-power, being made, according to report; the actual construction
of the latter size at this time, however, is doubtful.
Probably the best example of radial construction up to the outbreak
of War was the Salmson (Canton-Unne) water-cooled, of which in 1914
six sizes were listed as available. Of these the smallest was a
seven-cylinder 90 horse-power engine, and the largest, rated at 600
horse-power, had eighteen cylinders. These engines, during the War,
were made under licence by the Dudbridge Ironworks in Great Britain.
[Illustration: Section of 200 h.p. Salmson Radial Engine.]
The accompanying diagram shows the construction of the cylinders
in the 200 horse-power size, showing the method of cooling, and the
arrangement of the connecting rods. A patent planetary gear, also shown
in the diagram, gives exactly the same stroke to all the pistons. The
complete engine has fourteen cylinders, of forged steel machined all
over, and so secured to the crank case that any one can be removed
without parting the crank case. The water-jackets are of spun copper,
brazed on to the cylinder, and corrugated so as to admit of free
expansion; the water is circulated by means of a centrifugal pump.
The pistons are of cast-iron, each fitted with three rings, and the
connecting rods are of high-grade steel, machined all over and fitted
with bushes of phosphor bronze; these rods are connected to a central
collar, carried on the crank pin by two ball-bearings. The crankshaft
has a single throw, and is made in two parts to allow the cage for
carrying the big end-pins of the connecting rods to be placed in
position.
The casing is in two parts, on one of which the brackets for fixing the
engine are carried, while the other part carries the valve-gear. Bolts
secure the two parts together. The mechanically-operated steel valves
on the cylinders are each fitted with double springs, and the valves
are operated by rods and levers. Two Zenith carburettors are fitted
on the rear half of the crank case, and short induction pipes are led
to each cylinder; each of the carburettors is heated by the exhaust
gases. Ignition is by two high-tension magnetos, and a compressed air
self-starting arrangement is provided. Two oil pumps are fitted for
lubricating purposes, one of which forces oil to the crankshaft and
connecting-rod bearings, while the second forces oil to the valve
gear, the cylinders being so arranged that the oil which flows along
the walls cannot flood the lower cylinders. This engine operates upon
a six-stroke cycle, a rather rare arrangement for internal combustion
engines of the electrical ignition type; this is done in order to
obtain equal angular intervals for the working impulses imparted to the
rotating crankshaft, as the cylinders are arranged in groups of seven,
and all act upon the one crankshaft. The angle, therefore, between the
impulses is 77-1/7 degrees. A diagram is inset giving a side view of
the engine, in order to show the grouping of the cylinders.
[Illustration: Salmson 200 h.p. Radial Engine, Side View.]
The 600 horse-power Salmson engine was designed with a view to fitting
to airships, and was in reality two nine-cylindered engines, with a
gear-box connecting them; double air-screws were fitted, and these
were so arranged that either or both of them might be driven by either
or both engines; in addition to this, the two engines were complete
and separate engines as regards carburation and ignition, etc., so
that they could be run independently of each other. The cylinders were
exceptionally ‘long stroke,’ being 5·9 inches bore to 8·27 inches
stroke, and the rated power was developed at 1,200 revolutions per
minute, the weight of the complete engine being only 4·1 lbs. per
horse-power at the normal rating.
A type of engine specially devised for airship propulsion is that in
which the cylinders are arranged horizontally instead of vertically,
the main advantages of this form being the reduction of head resistance
and less obstruction to the view of the pilot. A casing, mounted on
the top of the engine, supports the air-screw, which is driven through
bevel gearing from the upper end of the crankshaft. With this type of
engine a better rate of air-screw efficiency is obtained by gearing the
screw down to half the rate of revolution of the engine, this giving a
more even torque. The petrol consumption of the type is very low, being
only 0·48 lbs. per horse-power per hour, and equal economy is claimed
as regards lubricating oil, a consumption of as little as 0·04 lbs. per
horse-power per hour being claimed.
Certain American radial engines were made previous to 1914, the
principal being the Albatross six-cylinder engines of 50 and 100
horse-powers. Of these the smaller size was air-cooled, with
cylinders of 4·5 inches bore and 5 inches stroke, developing the
rated power at 1,230 revolutions per minute, with a weight of about
5 lbs. per horse-power. The 100 horse-power size had cylinders of
5·5 inches bore, developing its rated power at 1,230 revolutions per
minute, and weighing only 2·75 lbs. per horse-power. This engine was
markedly similar to the six-cylindered Anzani, having all the valves
mechanically operated, and with auxiliary exhaust ports at the bottoms
of the cylinders, overrun by long pistons. These Albatross engines
had their cylinders arranged in two groups of three, with each group
of three pistons operating on one of two crank pins, each 180 degrees
apart.
The radial type of engine, thanks to Charles Manly, had the honour of
being first in the field as regards aero work. Its many advantages,
among which may be specially noted the very short crankshaft as
compared with vertical, Vee, or ‘broad arrow’ type of engine, and
consequent greater rigidity, ensure it consideration by designers of
to-day, and render it certain that the type will endure. Enthusiasts
claim that the ‘broad arrow’ type, or Vee with a third row of cylinders
inset between the original two, is just as much a development from the
radial engine as from the vertical and resulting Vee; however this may
be, there is a place for the radial type in air-work for as long as the
internal combustion engine remains as a power plant.
IV
THE ROTARY TYPE
M. Laurent Seguin, the inventor of the Gnome rotary aero engine,
provided as great a stimulus to aviation as any that was given anterior
to the war period, and brought about a great advance in mechanical
flight, since these well-made engines gave a high-power output for
their weight, and were extremely smooth in running. In the rotary
design the crankshaft of the engine is stationary, and the cylinders,
crank case, and all their adherent parts rotate; the working is thus
exactly opposite in principle to that of the radial type of aero
engine, and the advantage of the rotary lies in the considerable
flywheel effect produced by the revolving cylinders, with consequent
evenness of torque. Another advantage is that air-cooling, adopted in
all the Gnome engines, is rendered much more effective by the rotation
of the cylinders, though there is a tendency to distortion through the
leading side of each cylinder being more efficiently cooled than the
opposite side; advocates of other types are prone to claim that the air
resistance to the revolving cylinders absorbs some 10 per cent of the
power developed by the rotary engine, but that has not prevented the
rotary from attaining to great popularity as a prime mover.
There were, in the list of aero engines compiled in 1910, five rotary
engines included, all air-cooled. Three of these were Gnome engines,
and two of the make known as ‘International.’ They ranged from 21·5
to 123 horse-power, the latter being rated at only 1·8 lbs. weight
per brake horse-power, and having fourteen cylinders, 4·33 inches in
diameter by 4·7 inches stroke. By 1914 forty-three different sizes and
types of rotary engine were being constructed, and in 1913 five rotary
type engines were entered for the series of aeroplane engine trials
held in Germany. Minor defects ruled out four of these, and only the
German Bayerischer Motoren Flugzeugwerke completed the seven-hour test
prescribed for competing engines. Its large fuel consumption barred
this engine from the final trials, the consumption being some 0·95
pints per horse-power per hour. The consumption of lubricating oil,
also was excessive, standing at 0·123 pint per horse-power per hour.
The engine gave 37·5 effective horse-power during its trial, and the
loss due to air resistance was 4·6 horse-power, about 11 per cent.
The accompanying drawing shows the construction of the engine, in
which the seven cylinders are arranged radially on the crank case; the
method of connecting the pistons to the crank pins can be seen. The
mixture is drawn through the crank chamber, and to enter the cylinder
it passes through the two automatic valves in the crown of the piston;
the exhaust valves are situated in the tops of the cylinders, and are
actuated by cams and push-rods. Cooling of the cylinder is assisted by
the radial rings, and the diameter of these rings is increased round
the hottest part of the cylinder. When long flights are undertaken
the advantage of the light weight of this engine is more than
counterbalanced by its high fuel and lubricating oil consumption, but
there are other makes which are much better than this seven-cylinder
German in respect of this.
[Illustration: Bayerischer 7 Cylinder Rotary Engine, 1913.]
Rotation of the cylinders in engines of this type is produced by the
side pressure of the pistons on the cylinder walls, and in order to
prevent this pressure from becoming abnormally large it is necessary to
keep the weight of the piston as low as possible, as the pressure is
produced by the tangential acceleration and retardation of the piston.
On the upward stroke the circumferential velocity of the piston is
rapidly increased, which causes it to exert a considerable tangential
pressure on the side of the cylinder, and on the return stroke there
is a corresponding retarding effect due to the reduction of the
circumferential velocity of the piston. These side pressures cause an
appreciable increase in the temperatures of the cylinders and pistons,
which makes it necessary to keep the power rating of the engines fairly
low.
Seguin designed his first Gnome rotary as a 34 horse-power engine when
run at a speed of 1,300 revolutions per minute. It had five cylinders,
and the weight was 3·9 lbs. per horse-power. A seven-cylinder model
soon displaced this first engine, and this latter, with a total weight
of 165 lbs., gave 61·5 horse-power. The cylinders were machined out of
solid nickel chrome-steel ingots, and the machining was carried out
so that the cylinder walls were under ⅙ of an inch in thickness. The
pistons were cast-iron, fitted each with two rings, and the automatic
inlet valve to the cylinder was placed in the crown of the piston. The
connecting rods, of ‘H’ section, were of nickel chrome-steel, and the
large end of one rod, known as the ‘master-rod’ embraced the crank pin;
on the end of this rod six hollow steel pins were carried, and to these
the remaining six connecting-rods were attached. The crankshaft of the
engine was made of nickel chrome-steel, and was in two parts connected
together at the crank pin; these two parts, after the master-rod had
been placed in position and the other connecting rods had been attached
to it, were firmly secured. The steel crank case was made in five
parts, the two central ones holding the cylinders in place, and on one
side another of the five castings formed a cam-box, to the outside of
which was secured the extension to which the air-screw was attached.
On the other side of the crank case another casting carried the
thrust-box, and the whole crank case, with its cylinders and gear, was
carried on the fixed crank shaft by means of four ball-bearings, one of
which also took the axial thrust of the air-screw.
For these engines, castor oil is the lubricant usually adopted, and it
is pumped to the crankshaft by means of a gear-driven oil pump; from
this shaft the other parts of the engine are lubricated by means of
centrifugal force, and in actual practice sufficient unburnt oil passes
through the cylinders to lubricate the exhaust valve, which partly
accounts for the high rate of consumption of lubricating oil. A very
simple carburettor of the floatless, single-spray type was used, and
the mixture was passed along the hollow crankshaft to the interior of
the crank case, thence through the automatic inlet valves in the tops
of the pistons to the combustion chambers of the cylinders. Ignition
was by means of a high-tension magneto specially geared to give the
correct timing, and the working impulses occurred at equal angular
intervals of 102·85 degrees. The ignition was timed so that the firing
spark occurred when the cylinder was 26 degrees before the position in
which the piston was at the outer end of its stroke, and this timing
gave a maximum pressure in the cylinder just after the piston had
passed this position.
By 1913, eight different sizes of the Gnome engine were being
constructed, ranging from 45 to 180 brake horse-power; four of these
were single-crank engines, one having nine and the other three having
seven cylinders. The remaining four were constructed with two cranks;
three of them had fourteen cylinders apiece, ranged in groups of seven,
acting on the cranks, and the one other had eighteen cylinders ranged
in two groups of nine, acting on its two cranks. Cylinders of the
two-crank engines are so arranged (in the fourteen-cylinder type) that
fourteen equal angular impulses occur during each cycle; these engines
are supported on bearings on both sides of the engine, the air-screw
being placed outside the front support. In the eighteen-cylinder model
the impulses occur at each 40 degrees of angular rotation of the
cylinders, securing an extremely even rotation of the air-screw.
In 1913 the Gnome Monosoupape engine was introduced, a model in which
the inlet valve to the cylinder was omitted, while the piston was of
the ordinary cast-iron type. A single exhaust valve in the cylinder
head was operated in a manner similar to that on the previous Gnome
engines, and the fact of this being the only valve on the cylinder
gave the engine its name. Each cylinder contained ports at the bottom
which communicated with the crank chamber, and were overrun by the
piston when this was approaching the bottom end of its stroke. During
the working cycle of the engine the exhaust valve was opened early to
allow the exhaust gases to escape from the cylinder, so that by the
time the piston overran the ports at the bottom the pressure within
the cylinder was approximately equal to that in the crank case, and
practically no flow of gas took place in either direction through the
ports. The exhaust valve remained open as usual during the succeeding
up-stroke of the piston, and the valve was held open until the piston
had returned through about one-third of its downward stroke, thus
permitting fresh air to enter the cylinder. The exhaust valve then
closed, and the downward motion of the piston, continuing, caused a
partial vacuum inside the cylinder; when the piston overran the ports,
the rich mixture from the crank case immediately entered. The cylinder
was then full of the mixture, and the next upward stroke of the piston
compressed the charge; upon ignition the working cycle was repeated.
The speed variation of this engine was obtained by varying the extent
and duration of the opening of the exhaust valves, and was controlled
by the pilot by hand-operated levers acting on the valve tappet
rollers. The weight per horse-power of these engines was slightly less
than that of the two-valve type, while the lubrication of the gudgeon
pin and piston showed an improvement, so that a lower lubricating oil
consumption was obtained. The 100 horse-power Gnome Monosoupape was
built with nine cylinders, each 4·33 inches bore by 5·9 inches stroke,
and it developed its rated power at 1,200 revolutions per minute.
[Illustration: Clerget 115 h.p. Rotary Aero Engine, Side Elevation.]
An engine of the rotary type, almost as well known as the Gnome, is
the Clerget, in which both cylinders and crank case are made of steel,
the former having the usual radial fins for cooling. In this type the
inlet and exhaust valves are both located in the cylinder head, and
mechanically operated by push-rods and rockers. Pipes are carried from
the crank case to the inlet valve casings to convey the mixture to the
cylinders, a carburettor of the central needle type being used. The
carburetted mixture is taken into the crank case chamber in a manner
similar to that of the Gnome engine. Pistons of aluminium alloy, with
three cast-iron rings, are fitted, the top ring being of the obturator
type. The large end of one of the nine connecting rods embraces the
crank pin and the pressure is taken on two ball-bearings housed in the
end of the rod. This carries eight pins, to which the other rods are
attached, and the main rod being rigid between the crank pin and piston
pin determines the position of the pistons. Hollow connecting-rods
are used, and the lubricating oil for the piston pins passes from the
crankshaft through the centres of the rods. Inlet and exhaust valves
can be set quite independently of one another--a useful point, since
the correct timing of the opening of these valves is of importance. The
inlet valve opens 4 degrees from top centre and closes after the bottom
dead centre of the piston; the exhaust valve opens 68 degrees before
the bottom centre and closes 4 degrees after the top dead centre of
the piston. The magnetos are set to give the spark in the cylinder at
25 degrees before the end of the compression stroke--two high-tension
magnetos are used; if desired, the second one can be adjusted to give
a later spark for assisting the starting of the engine. The lubricating
oil pump is of the valveless two-plunger type, so geared that it runs
at seven revolutions to 100 revolutions of the engine; by counting
the pulsations the speed of the engine can be quickly calculated by
multiplying the pulsations by 100 and dividing by seven. In the 115
horse-power nine-cylinder Clerget the cylinders are 4·7 bore with a
6·3 inches stroke, and the rated power of the engine is obtained at
1,200 revolutions per minute. The petrol consumption is 0·75 pint per
horse-power per hour.
A third rotary aero engine, equally well known with the foregoing
two, is the Le Rhone, made in four different sizes with power outputs
of from 50 to 160 horse-power; the two smaller sizes are single
crank engines with seven and nine cylinders respectively, and the
larger sizes are of double-crank design, being merely the two smaller
sizes doubled--fourteen and eighteen-cylinder engines. The inlet and
exhaust valves are located in the cylinder head, and both valves are
mechanically operated by one push-rod and rocker, radial pipes from
crank case to inlet valve casing taking the mixture to the cylinders.
The exhaust valves are placed on the leading, or air-screw side, of
the engine, in order to get the fullest possible cooling effect. The
rated power of each type of engine is obtained at 1,200 revolutions
per minute, and for all four sizes the cylinder bore is 4·13 inches,
with a 5·5 inches piston stroke. Thin cast-iron liners are shrunk
into the steel cylinders in order to reduce the amount of piston
friction. Although the Le Rhone engines are constructed practically
throughout of steel, the weight is only 2·9 lbs. per horse-power in the
eighteen-cylinder type.
[Illustration: Gyro-Duplex Rotary Engine, Cross Section.]
American enterprise in the construction of the rotary type is perhaps
best illustrated in the ‘Gyro’ engine; this was first constructed with
inlet valves in the heads of the pistons, after the Gnome pattern, the
exhaust valves being in the heads of the cylinders. The inlet valve in
the crown of each piston was mechanically operated in a very ingenious
manner by the oscillation of the connecting-rod. The Gyro-Duplex engine
superseded this original design, and a small cross-section illustration
of this is appended. It is constructed in seven and nine-cylinder
sizes, with a power range of from 50 to 100 horse-power; with the
largest size the low weight of 2·5 lbs. per horse-power is reached. The
design is of considerable interest to the internal combustion engineer,
for it embodies a piston valve for controlling auxiliary exhaust
ports, which also acts as the inlet valve to the cylinder. The piston
uncovers the auxiliary ports when it reaches the bottom of its stroke,
and at the end of the power stroke the piston is in such a position
that the exhaust can escape over the top of it. The exhaust valve in
the cylinder head is then opened by means of the push-rod and rocker,
and is held open until the piston has completed its upward stroke and
returned through more than half its subsequent return stroke. When the
exhaust valve closes, the cylinder has a charge of fresh air, drawn in
through the exhaust valve, and the further motion of the piston causes
a partial vacuum; by the time the piston reaches bottom dead centre the
piston-valve has moved up to give communication between the cylinder
and the crank case, therefore the mixture is drawn into the cylinder.
Both the piston valve and exhaust valve are operated by cams formed on
the one casting, which rotates at seven-eighths engine speed for the
seven-cylinder type, and nine-tenths engine speed for the nine-cylinder
engines. Each of these cams has four or five points respectively, to
suit the number of cylinders.
The steel cylinders are machined from solid forgings and provided with
webs for air-cooling as shown. Cast-iron pistons are used, and are
connected to the crankshaft in the same manner as with the Gnome and Le
Rhone engines. Petrol is sprayed into the crank case by a small geared
pump and the mixture is taken from there to the piston valves by radial
pipes. Two separate pumps are used for lubrication, one forcing oil to
the crank-pin bearing and the other spraying the cylinders.
Among other designs of rotary aero engines the E.J.C. is noteworthy,
in that the cylinders and crank case of this engine rotate in opposite
directions, and two air-screws are used, one being attached to the end
of the crankshaft, and the other to the crank case. Another interesting
type is the Burlat rotary, in which both the cylinders and crankshaft
rotate in the same direction, the rotation of the crankshaft being
twice that of the cylinders as regards speed. This engine is arranged
to work on the four-stroke cycle with the crankshaft making four, and
the cylinders two, revolutions per cycle.
It would appear that the rotary type of engine is capable of but little
more improvement--save for such devices as these of the last two
engines mentioned, there is little that Laurent Seguin has not already
done in the Gnome type. The limitation of the rotary lies in its
high fuel and lubricating oil consumption, which renders it unsuited
for long-distance aero work; it was, in the war period, an admirable
engine for such short runs as might be involved in patrol work ‘over
the lines,’ and for similar purposes, but the water-cooled Vee or
even vertical, with its much lower fuel consumption, was and is to be
preferred for distance work. The rotary air-cooled type has its uses,
and for them it will probably remain among the range of current types
for some time to come. Experience of matters aeronautical is sufficient
to show, however, that prophecy in any direction is most unsafe.
V
THE HORIZONTALLY-OPPOSED ENGINE
Among the first internal combustion engines to be taken into use with
aircraft were those of the horizontally-opposed four-stroke cycle
type, and, in every case in which these engines were used, their
excellent balance and extremely even torque rendered them ideal--until
the tremendous increase in power requirements rendered the type too
long and bulky for placing in the fuselage of an aeroplane. As power
increased, there came a tendency toward placing cylinders radially
round a central crankshaft, and, as in the case of the early Anzani, it
may be said that the radial engine grew out of the horizontal opposed
piston type. There were, in 1910--that is, in the early days of small
power units, ten different sizes of the horizontally opposed engine
listed for manufacture, but increase in power requirements practically
ruled out the type for air work.
The Darracq firm were the leading makers of these engines in 1910;
their smallest size was a 24 horse-power engine, with two cylinders
each of 5·1 inches bore by 4·7 inches stroke. This engine developed
its rated power at 1,500 revolutions per minute, and worked out at
a weight of 5 lbs. per horse-power. With these engines the cranks
are so placed that two regular impulses are given to the crankshaft
for each cycle of working, an arrangement which permits of very even
balancing of the inertia forces of the engine. The Darracq firm also
made a four-cylindered horizontal opposed piston engine, in which two
revolutions were given to the crankshaft per revolution, at equal
angular intervals.
The Dutheil-Chambers was another engine of this type, and had the
distinction of being the second largest constructed. At 1,000
revolutions per minute it developed 97 horse-power; its four cylinders
were each of 4·93 inches bore by 11·8 inches stroke--an abnormally long
stroke in comparison with the bore. The weight--which owing to the
build of the engine and its length of stroke was bound to be rather
high, actually amounted to 8·2 lbs. per horse-power. Water cooling
was adopted, and the engine was, like the Darracq four-cylinder type,
so arranged as to give two impulses per revolution at equal angular
intervals of crankshaft rotation.
One of the first engines of this type to be constructed in England was
the Alvaston, a water-cooled model which was made in 20, 30, and 50
brake horse-power sizes, the largest being a four-cylinder engine. All
three sizes were constructed to run at 1,200 revolutions per minute.
In this make the cylinders were secured to the crank case by means of
four long tie bolts passing through bridge pieces arranged across the
cylinder heads, thus relieving the cylinder walls of all longitudinal
explosion stresses. These bridge pieces were formed from chrome
vanadium steel and milled to an ‘H’ section, and the bearings for the
valve-tappet were forged solid with them. Special attention was given
to the machining of the interiors of the cylinders and the combustion
heads, with the result that the exceptionally high compression of 95
lbs. per square inch was obtained, giving a very flexible engine. The
cylinder heads were completely water-jacketed, and copper water-jackets
were also fitted round the cylinders. The mechanically operated valves
were actuated by specially shaped cams, and were so arranged that only
two cams were required for the set of eight valves. The inlet valves at
both ends of the engine were connected by a single feed-pipe to which
the carburettor was attached, the induction piping being arranged above
the engine in an easily accessible position. Auxiliary air ports were
provided in the cylinder walls so that the pistons overran them at the
end of their stroke. A single vertical shaft running in ball-bearings
operated the valves and water circulating pump, being driven by spiral
gearing from the crankshaft at half speed. In addition to the excellent
balance obtained with this engine, the makers claimed with justice that
the number of working parts was reduced to an absolute minimum.
In the two-cylinder Darracq, the steel cylinders were machined from
solid, and auxiliary exhaust ports, overrun by the piston at the inner
end of its stroke, were provided in the cylinder walls, consisting of
a circular row of drilled holes--this arrangement was subsequently
adopted on some of the Darracq racing car engines. The water jackets
were of copper, soldered to the cylinder walls; both the inlet and
exhaust valves were located in the cylinder heads, being operated by
rockers and push-rods actuated by cams on the half-time shaft driven
from one end of the crankshaft. Ignition was by means of a high-tension
magneto, and long induction pipes connected the ends of the cylinders
to the carburettor, the latter being placed underneath the engine.
Lubrication was effected by spraying oil into the crank case by means
of a pump, and a second pump circulated the cooling water.
Another good example of this type of engine was the Eole, which had
eight opposed pistons, each pair of which was actuated by a common
combustion chamber at the centre of the engine, two crankshafts being
placed at the outer ends of the engine. This reversal of the ordinary
arrangement had two advantages; it simplified induction, and further
obviated the need for cylinder heads, since the explosion drove at two
piston heads instead of at one piston head and the top of the cylinder;
against this, however, the engine had to be constructed strongly enough
to withstand the longitudinal stresses due to the explosions, as the
cranks are placed on the outer ends and the cylinders and crank-cases
take the full force of each explosion. Each crankshaft drove a separate
air-screw.
This pattern of engine was taken up by the Dutheil-Chambers firm in
the pioneer days of aircraft, when the firm in question produced
seven different sizes of horizontal engines. The Demoiselle monoplane
used by Santos-Dumont in 1909 was fitted with a two-cylinder,
horizontally-opposed Dutheil-Chambers engine, which developed 25 brake
horse-power at a speed of 1,100 revolutions per minute, the cylinders
being of 5 inches bore by 5·1 inches stroke, and the total weight
of the engine being some 120 lbs. The crankshafts of these engines
were usually fitted with steel flywheels in order to give a very even
torque, the wheels being specially constructed with wire spokes. In
all the Dutheil-Chambers engines water cooling was adopted, and the
cylinders were attached to the crank cases by means of long bolts
passing through the combustion heads.
For their earliest machines, the Clement-Bayard firm constructed
horizontal engines of the opposed piston type. The best known of these
was the 30 horse-power size, which had cylinders of 4·7 inches diameter
by 5·1 inches stroke, and gave its rated power at 1,200 revolutions
per minute. In this engine the steel cylinders were secured to the
crank case by flanges, and radiating ribs were formed around the barrel
to assist the air-cooling. Inlet and exhaust valves were actuated by
push-rods and rockers actuated from the second motion shaft mounted
above the crank case; this shaft also drove the high-tension magneto
with which the engine was fitted. A ring of holes drilled round each
cylinder constituted auxiliary ports which the piston uncovered at the
inner end of its stroke, and these were of considerable assistance not
only in expelling exhaust gases, but also in moderating the temperature
of the cylinder and of the main exhaust valve fitted in the cylinder
head. A water-cooled Clement-Bayard horizontal engine was also made,
and in this the auxiliary exhaust ports were not embodied; except
in this particular, the engine was very similar to the water-cooled
Darracq.
The American Ashmusen horizontal engine, developing 100 horse-power,
is probably the largest example of this type constructed. It was made
with six cylinders arranged on each side of a common crank case, with
long bolts passing through the cylinder heads to assist in holding them
down. The induction piping and valve-operating gear were arranged below
the engine, and the half-speed shaft carried the air-screw.
Messrs Palons and Beuse, Germans, constructed a light-weight,
air-cooled, horizontally-opposed engine, two-cylindered. In this the
cast-iron cylinders were made very thin, and were secured to the
crank case by bolts passing through lugs cast on the outer ends of
the cylinders; the crankshaft was made hollow, and holes were drilled
through the webs of the connecting-rods in order to reduce the weight.
The valves were fitted to the cylinder heads, the inlet valves being of
the automatic type, while the exhaust valves were mechanically operated
from the cam-shaft by means of rockers and push-rods. Two carburettors
were fitted, to reduce the induction piping to a minimum; one was
attached to each combustion chamber, and ignition was by the normal
high-tension magneto driven from the half-time shaft.
There was also a Nieuport two-cylinder air-cooled horizontal engine,
developing 35 horse-power when running at 1,300 revolutions per minute,
and being built at a weight of 5 lbs. per horse-power. The cylinders
were of 5·3 inches diameter by 5·9 inches stroke; the engine followed
the lines of the Darracq and Dutheil-Chambers pretty closely, and thus
calls for no special description.
The French Kolb-Danvin engine of the horizontal type, first constructed
in 1905, was probably the first two-stroke cycle engine designed
to be applied to the propulsion of aircraft; it never got beyond
the experimental stage, although its trials gave very good results.
Stepped pistons were adopted, and the charging pump at one end was
used to scavenge the power cylinder at the other ends of the engine,
the transfer ports being formed in the main casting. The openings of
these ports were controlled at both ends by the pistons, and the
location of the ports appears to have made it necessary to take the
exhaust from the bottom of one cylinder and from the top of the other.
The carburetted mixture was drawn into the scavenging cylinders, and
the usual deflectors were cast on the piston heads to assist in the
scavenging and to prevent the fresh gas from passing out of the exhaust
ports.
VI
THE TWO-STROKE CYCLE ENGINE
Although it has been little used for aircraft propulsion, the
possibilities of the two-stroke cycle engine render some study of
it desirable in this brief review of the various types of internal
combustion engine applicable both to aeroplanes and airships.
Theoretically the two-stroke cycle engine--or as it is more commonly
termed, the ‘two-stroke,’ is the ideal power producer; the doubling
of impulses per revolution of the crankshaft should render it of
very much more even torque than the four-stroke cycle types, while,
theoretically, there should be a considerable saving of fuel, owing
to the doubling of the number of power strokes per total of piston
strokes. In practice, however, the inefficient scavenging of virtually
every two-stroke cycle engine produced nullifies or more than nullifies
its advantages over the four-stroke cycle engine; in many types, too,
there is a waste of fuel gases through the exhaust ports, and much has
yet to be done in the way of experiment and resulting design before
the two-stroke cycle engine can be regarded as equally reliable,
economical, and powerful with its elder brother.
The first commercially successful engine operating on the two-stroke
cycle was invented by Mr Dugald Clerk, who in 1881 proved the design
feasible. As is more or less generally understood, the exhaust gases
of this engine are discharged from the cylinder during the time that
the piston is passing the inner dead centre, and the compression,
combustion, and expansion of the charge take place in similar manner
to that of the four-stroke cycle engine. The exhaust period is usually
controlled by the piston overrunning ports in the cylinder at the end
of its working stroke, these ports communicating direct with the outer
air--the complication of an exhaust valve is thus obviated; immediately
after the escape of the exhaust gases, charging of the cylinder occurs,
and the fresh gas may be introduced either through a valve in the
cylinder head or through ports situated diametrically opposite to the
exhaust ports. The continuation of the outward stroke of the piston,
after the exhaust ports have been closed, compresses the charge into
the combustion chamber of the cylinder, and the ignition of the mixture
produces a recurrence of the working stroke.
Thus, theoretically, is obtained the maximum of energy with the minimum
of expenditure; in practice, however, the scavenging of the power
cylinder, a matter of great importance in all internal combustion
engines, is often imperfect, owing to the opening of the exhaust ports
being of relatively short duration; clearing the exhaust gases out
of the cylinder is not fully accomplished, and these gases mix with
the fresh charge and detract from its efficiency. Similarly, owing to
the shorter space of time allowed, the charging of the cylinder with
the fresh mixture is not so efficient as in the four-stroke cycle
type; the fresh charge is usually compressed slightly in a separate
chamber--crank case, independent cylinder, or charging pump, and is
delivered to the working cylinder during the beginning of the return
stroke of the piston, while in engines working on the four-stroke
cycle principle a complete stroke is devoted to the expulsion of the
waste gases of the exhaust, and another full stroke to recharging the
cylinder with fresh explosive mixture.
Theoretically the two-stroke and the four-stroke cycle engines possess
exactly the same thermal efficiency, but actually this is modified by a
series of practical conditions which to some extent tend to neutralise
the very strong case in favour of the two-stroke cycle engine. The
specific capacity of the engine operating on the two-stroke principle
is theoretically twice that of one operating on the four-stroke cycle,
and consequently, for equal power, the former should require only about
half the cylinder volume of the latter; and, owing to the greater
superficial area of the smaller cylinder, relatively, the latter should
be far more easily cooled than the larger four-stroke cycle cylinder;
thus it should be possible to get higher compression pressures,
which in turn should result in great economy of working. Also the
obtaining of a working impulse in the cylinder for each revolution
of the crankshaft should give a great advantage in regularity of
rotation--which it undoubtedly does--and the elimination of the
operating gear for the valves, inlet and exhaust, should give greater
simplicity of design.
In spite of all these theoretical--and some practical--advantages the
four-stroke cycle engine was universally adopted for aircraft work;
owing to the practical equality of the two principles of operation,
so far as thermal efficiency and friction losses are concerned,
there is no doubt that the simplicity of design (in theory) and
high power output to weight ratio (also in theory) ought to have
given the ‘two-stroke’ a place on the aeroplane. But this engine has
to be developed so as to overcome its inherent drawbacks; better
scavenging methods have yet to be devised--for this is the principal
drawback--before the two-stroke can come to its own as a prime mover
for aircraft.
Mr Dugald Clerk’s original two-stroke cycle engine is indicated
roughly, as regards principle, by the accompanying diagram, from which
it will be seen that the elimination of the ordinary inlet and exhaust
valves of the four-stroke type is more than compensated by a separate
cylinder which, having a piston worked from the connecting-rod of the
power cylinder, was used to charging, drawing the mixture from the
carburettor past the valve in the top of the charging cylinder, and
then forcing it through the connecting pipe into the power cylinder.
The inlet valves both on the charging and the power cylinders are
automatic; when the power piston is near the bottom of its stroke the
piston in the charging cylinder is compressing the carburetted air,
so that as soon as the pressure within the power cylinder is relieved
by the exit of the burnt gases through the exhaust ports the pressure
in the charging cylinder causes the valve in the head of the power
cylinder to open, and fresh mixture flows into the cylinder, replacing
the exhaust gases. After the piston has again covered the exhaust ports
the mixture begins to be compressed, thus automatically closing the
inlet valve. Ignition occurs near the end of the compression stroke,
and the working stroke immediately follows, thus giving an impulse to
the crankshaft on every down stroke of the piston. If the scavenging
of the cylinder were complete, and the cylinder were to receive a
full charge of fresh mixture for every stroke, the same mean effective
pressure as is obtained with four-stroke cycle engines ought to be
realised, and at an equal speed of rotation this engine should give
twice the power obtainable from a four-stroke cycle engine of equal
dimensions. This result was not achieved, and, with the improvements
in construction brought about by experiment up to 1912, the output was
found to be only about fifty per cent more than that of a four-stroke
cycle engine of the same size, so that, when the charging cylinder is
included, this engine has a greater weight per horse-power, while the
lowest rate of fuel consumption recorded was 0.68 lb. per horse-power
per hour.
[Illustration: Dugald Clerk’s Two-stroke Cycle Engine.]
In 1891 Mr Day invented a two-stroke cycle engine which used the crank
case as a scavenging chamber, and a very large number of these engines
have been built for industrial purposes. The charge of carburetted air
is drawn through a non-return valve into the crank chamber during the
upstroke of the piston, and compressed to about 4 lbs. pressure per
square inch on the down stroke. When the piston approaches the bottom
end of its stroke the upper edge first overruns an exhaust port, and
almost immediately after uncovers an inlet port on the opposite side of
the cylinder and in communication with the crank chamber; the entering
charge, being under pressure, assists in expelling the exhaust gases
from the cylinder. On the next upstroke the charge is compressed into
the combustion space of the cylinder, a further charge simultaneously
entering the crank case to be compressed after the ignition for the
working stroke. To prevent the incoming charge escaping through the
exhaust ports of the cylinder a deflector is formed on the top of the
piston, causing the fresh gas to travel in an upward direction, thus
avoiding as far as possible escape of the mixture to the atmosphere.
From experiments conducted in 1910 by Professor Watson and Mr Fleming
it was found that the proportion of fresh gases which escaped unburnt
through the exhaust ports diminished with increase of speed; at 600
revolutions per minute about 36 per cent of the fresh charge was lost;
at 1,200 revolutions per minute this was reduced to 20 per cent, and at
1,500 revolutions it was still farther reduced to 6 per cent.
So much for the early designs. With regard to engines of this type
specially constructed for use with aircraft, three designs call for
special mention. Messrs A. Gobe and H. Diard, Parisian engineers,
produced an eight-cylindered two-stroke cycle engine of rotary design,
the cylinders being co-axial. Each pair of opposite pistons was secured
together by a rigid connecting rod, connected to a pin on a rotating
crankshaft which was mounted eccentrically to the axis of rotation
of the cylinders. The crankshaft carried a pinion gearing with an
internally toothed wheel on the transmission shaft which carried the
air-screw. The combustible mixture, emanating from a common supply
pipe, was led through conduits to the front ends of the cylinders,
in which the charges were compressed before being transferred to the
working spaces through ports in tubular extensions carried by the
pistons. These extensions had also exhaust ports, registering with
ports in the cylinder which communicated with the outer air, and the
extensions slid over depending cylinder heads attached to the crank
case by long studs. The pump charge was compressed in one end of each
cylinder, and the pump spaces each delivered into their corresponding
adjacent combustion spaces. The charges entered the pump spaces during
the suction period through passages which communicated with a central
stationary supply passage at one end of the crank case, communication
being cut off when the inlet orifice to the passage passed out of
register with the port in the stationary member. The exhaust ports at
the outer end of the combustion space opened just before and closed a
little later than the air ports, and the incoming charge assisted in
expelling the exhaust gases in a manner similar to that of the earlier
types of two-stroke cycle engine. The accompanying rough diagram
assists in showing the working of this engine.
[Illustration: The Gobe and Diard Co-axial Two-stroke Engine.]
Exhibited in the Paris Aero Exhibition of 1912, the Laviator two-stroke
cycle engine, six-cylindered, could be operated either as a radial or
as a rotary engine, all its pistons acting on a single crank. Cylinder
dimensions of this engine were 3.94 inches bore by 5.12 inches stroke,
and a power output of 50 horse-power was obtained when working at
a rate of 1,200 revolutions per minute. Used as a radial engine, it
developed 65 horse-power at the same rate of revolution, and, as
the total weight was about 198 lbs., the weight of about 3 lbs. per
horse-power was attained in radial use. Stepped pistons were employed,
the annular space between the smaller or power piston and the walls
of the larger cylinder being used as a charging pump for the power
cylinder situated 120 degrees in rear of it. The charging cylinders
were connected by short pipes to ports in the crank case which
communicated with the hollow crankshaft through which the fresh gas was
supplied, and once in each revolution each port in the case registered
with the port in the hollow shaft. The mixture which then entered the
charging cylinder was transferred to the corresponding working cylinder
when the piston of that cylinder had reached the end of its power
stroke, and immediately before this the exhaust ports diametrically
opposite the inlet ports were uncovered; scavenging was thus assisted
in the usual way. The very desirable feature of being entirely
valveless was accomplished with this engine, which is also noteworthy
for exceedingly compact design.
The Lamplough six-cylinder two-stroke cycle rotary, shown at the Aero
Exhibition at Olympia in 1911, had several innovations, including a
charging pump of rotary blower type. With the six cylinders, six power
impulses at regular intervals were given on each rotation; otherwise,
the cycle of operations was carried out much as in other two-stroke
cycle engines. The pump supplied the mixture under slight pressure
to an inlet port in each cylinder, which was opened at the same time
as the exhaust port, the period of opening being controlled by the
piston. The rotary blower sucked the mixture from the carburettor and
delivered it to a passage communicating with the inlet ports in the
cylinder walls. A mechanically-operated exhaust valve was placed in the
centre of each cylinder head, and towards the end of the working stroke
this valve opened, allowing part of the burnt gases to escape to the
atmosphere; the remainder was pushed out by the fresh mixture going
in through the ports at the bottom end of the cylinder. In practice,
one or other of the cylinders was always taking fresh mixture while
working, therefore the delivery from the pump was continuous and the
mixture had not to be stored under pressure.
The piston of this engine was long enough to keep the ports covered
when it was at the top of the stroke, and a bottom ring was provided
to prevent the mixture from entering the crank case. In addition to
preventing leakage, this ring no doubt prevented an excess of oil
working up the piston into the cylinder. As the cylinder fired with
every revolution, the valve gear was of the simplest construction, a
fixed cam lifting each valve as the cylinder came into position. The
spring of the exhaust valve was not placed round the stem in the usual
way, but at the end of a short lever, away from the heat of the exhaust
gases. The cylinders were of cast steel, the crank case of aluminium,
and ball-bearings were fitted to the crankshaft, crank pins, and the
rotary blower pump. Ignition was by means of a high-tension magneto of
the two-spark pattern, and with a total weight of 300 lbs. the maximum
output was 102 brake horse-power, giving a weight of just under 3 lbs.
per horse-power.
One of the most successful of the two-stroke cycle engines was that
designed by Mr G. F. Mort and constructed by the New Engine Company.
With four cylinders of 3.69 inches bore by 4.5 inches stroke, and
running at 1,250 revolutions per minute, this engine developed 50
brake horse-power; the total weight of the engine was 155 lbs., thus
giving a weight of 3.1 lbs. per horse-power. A scavenging pump of the
rotary type was employed, driven by means of gearing from the engine
crankshaft, and in order to reduce weight to a minimum the vanes were
of aluminium. This engine was tried on a biplane, and gave very
satisfactory results.
American design yields two apparently successful two-stroke cycle
aero engines. A rotary called the Fredericson engine was said to give
an output of 70 brake horse-power with five cylinders 4·5 inches
diameter by 4·75 inches stroke, running at 1,000 revolutions per
minute. Another, the Roberts two-stroke cycle engine, yielded 100
brake horse-power from six cylinders of the stepped piston design;
two carburettors, each supplying three cylinders, were fitted
to this engine. Ignition was by means of the usual high-tension
magneto, gear-driven from the crankshaft, and the engine, which was
water-cooled, was of compact design.
It may thus be seen that the two-stroke cycle type got as far as actual
experiment in air work, and that with considerable success. So far,
however, the greater reliability of the four-stroke cycle has rendered
it practically the only aircraft engine, and the two-stroke has yet
some way to travel before it becomes a formidable competitor, in spite
of its admitted theoretical and questioned practical advantages.
VII
ENGINES OF THE WAR PERIOD
The principal engines of British, French, and American design used in
the war period and since are briefly described under the four distinct
types of aero engine; such notable examples as the Rolls-Royce,
Sunbeam, and Napier engines have been given special mention, as they
embodied--and still embody--all that is best in aero engine practice.
So far, however, little has been said about the development of German
aero engine design, apart from the early Daimler and other pioneer
makes.
At the outbreak of hostilities in 1914, thanks to subsidies to
contractors and prizes to aircraft pilots, the German aeroplane
industry was in a comparatively flourishing condition. There were about
twenty-two establishments making different types of heavier-than-air
machines, monoplane and biplane, engined for the most part with the
four-cylinder Argus or the six-cylinder Mercedes vertical type engines,
each of these being of 100 horse-power--it was not till war brought
increasing demands on aircraft that the limit of power began to rise.
Contemporary with the Argus and Mercedes were the Austro-Daimler,
Benz, and N.A.G., in vertical design, while as far as rotary types
were concerned there were two, the Oberursel and the Stahlhertz; of
these the former was by far the most promising, and it came to virtual
monopoly of the rotary-engined ‘plane as soon as the war demand began.
It was practically a copy of the famous Gnome rotary, and thus deserves
little description.
Germany, from the outbreak of war, practically, concentrated on the
development of the Mercedes engine; and it is noteworthy that, with one
exception, increase of power corresponding with the increased demand
for power was attained without increasing the number of cylinders. The
various models ranged between 75 and 260 horse-power, the latter being
the most recent production of this type. The exception to the rule
was the eight-cylinder 240 horse-power, which was replaced by the 260
horse-power six-cylinder model, the latter being more reliable and but
very slightly heavier. Of the other engines, the 120 horse-power Argus
and the 160 and 225 horse-power Benz were the most used, the Oberursel
being very largely discarded after the Fokker monoplane had had its
day, and the N.A.G. and Austro-Daimler also falling to comparative
disuse. It may be said that the development of the Mercedes engine
contributed very largely to such success as was achieved in the war
period by German aircraft, and, in developing the engine, the builders
were careful to make alterations in such a way as to effect the least
possible change in the design of aeroplane to which they were to be
fitted. Thus the engine base of the 175 horse-power model coincided
precisely with that of the 150 horse-power model, and the 200 and 240
horse-power models retained the same base dimensions. It was estimated,
in 1918, that well over eighty per cent of German aircraft was engined
with the Mercedes type.
In design and construction, there was nothing abnormal about the
Mercedes engine, the keynote throughout being extreme reliability and
such simplification of design as would permit of mass production in
different factories. Even before the war, the long list of records set
up by this engine formed practical application of the wisdom of this
policy; Bohn’s flight of 24 hours 10 minutes, accomplished on July 10th
and 11th, 1914, is an instance of this--the flight was accomplished on
an Albatross biplane with a 75 horse-power Mercedes engine. The radial
type, instanced in other countries by the Salmson and Anzani makes, was
not developed in Germany; two radial engines were made in that country
before the war, but the Germans seemed to lose faith in the type under
war conditions, or it may have been that insistence on standardisation
ruled out all but the proved examples of engine.
Details of one of the middle sizes of Mercedes motor, the 176
horse-power type, apply very generally to the whole range; this size
was in use up to and beyond the conclusion of hostilities, and it may
still be regarded as characteristic of modern (1920) German practice.
The engine is of the fixed vertical type, has six cylinders in line,
not off-set, and is water-cooled. The cam shaft is carried in a special
bronze casing, seated on the immediate top of the cylinders, and a
vertical shaft is interposed between crankshaft and camshaft, the
latter being driven by bevel gearing.
On this vertical connecting-shaft the water pump is located, serving
to steady the motion of the shaft. Extending immediately below the
camshaft is another vertical shaft, driven by bevel gears from the
crankshaft, and terminating in a worm which drives the multiple piston
oil pumps.
The cylinders are made from steel forgings, as are the valve chamber
elbows, which are machined all over and welded together. A jacket of
light steel is welded over the valve elbows and attached to a flange on
the cylinders, forming a water-cooling space with a section of about
7/16 of an inch. The cylinder bore is 5·5 inches, and the stroke 6·29
inches. The cylinders are attached to the crank case by means of dogs
and long through bolts, which have shoulders near their lower ends and
are bolted to the lower half of the crank chamber. A very light and
rigid structure is thus obtained, and the method of construction won
the flattery of imitation by makers of other nationality.
The cooling system for the cylinders is extremely efficient. After
leaving the water pump, the water enters the top of the front cylinders
and passes successively through each of the six cylinders of the row;
short tubes, welded to the tops of the cylinders, serve as connecting
links in the system. The Panhard car engines for years were fitted with
a similar cooling system, and the White and Poppe lorry engines were
also similarly fitted; the system gives excellent cooling effect where
it is most needed, round the valve chambers and the cylinder heads.
The pistons are built up from two pieces; a dropped forged steel
piston head, from which depend the piston pin bosses, is combined
with a cast-iron skirt, into which the steel head is screwed. Four
rings are fitted, three at the upper and one at the lower end of the
piston skirt, and two lubricating oil grooves are cut in the skirt,
in addition to the ring grooves. Two small rivets retain the steel
head on the piston skirt after it has been screwed into position, and
it is also welded at two points. The coefficient of friction between
the cast-iron and steel is considerably less than that which would
exist between two steel parts, and there is less tendency for the
skirt to score the cylinder walls than would be the case if all steel
were used--so noticeable is this that many makers, after giving steel
pistons a trial, discarded them in favour of cast-iron; the Gnome is an
example of this, being originally fitted with a steel piston carrying a
brass ring, discarded in favour of a cast-iron piston with a percentage
of steel in the metal mixture. In the Le Rhone engine the difficulty is
overcome by a cast-iron liner to the cylinders.
The piston pin of the Mercedes is of chrome nickel steel, and is
retained in the piston by means of a set screw and cotter pin. The
connecting rods, of I section, are very short and rigid, carrying
floating bronze bushes which fit the piston pins at the small end, and
carrying an oil tube on each for conveying oil from the crank pin to
the piston pin.
The crankshaft is of chrome nickel steel, carried on seven bearings.
Holes are drilled through each of the crank pins and main bearings,
for half the diameter of the shaft, and these are plugged with pressed
brass studs. Small holes, drilled through the crank cheeks, serve
to convey lubricant from the main bearings to the crank pins. The
propeller thrust is taken by a simple ball thrust bearing at the
propeller end of the crankshaft, this thrust bearing being seated in
a steel retainer which is clamped between the two halves of the crank
case. At the forward end of the crankshaft there is mounted a master
bevel gear on six splines; this bevel floats on the splines against
a ball thrust bearing, and, in turn, the thrust is taken by the crank
case cover. A stuffing box prevents the loss of lubricant out of the
front end of the crank chamber, and an oil thrower ring serves a
similar purpose at the propeller end of the crank chamber.
With a motor speed of 1,450 r.p.m., the vertical shaft at the forward
end of the motor turns at 2,175 r.p.m., this being the speed of the two
magnetos and the water pump. The lower vertical shaft bevel gear and
the magneto driving gear are made integral with the vertical driving
shaft, which is carried in plain bearings in an aluminium housing. This
housing is clamped to the upper half of the crank case by means of
three studs. The cam-shaft carries eighteen cams, these being the inlet
and exhaust cams, and a set of half compression cams which are formed
with the exhaust cams and are put into action when required by means of
a lever at the forward end of the cam-shaft. The cam-shaft is hollow,
and serves as a channel for the conveyance of lubricating oil to each
of the camshaft bearings. At the forward end of this shaft there is
also mounted an air pump for maintaining pressure on the fuel supply
tank, and a bevel gear tachometer drive.
Lubrication of the engine is carried out by a full pressure system.
The oil is pumped through a single manifold, with seven branches to
the crankshaft main bearings, and then in turn through the hollow
crankshaft to the connecting-rod big ends and thence through small
tubes, already noted, to the small end bearings. The oil pump has four
pistons and two double valves driven from a single eccentric shaft on
which are mounted four eccentrics. The pump is continuously submerged
in oil; in order to avoid great variations in pressure in the oil lines
there is a piston operated pressure regulator, cut in between the
pump and the oil lines. The two small pistons of the pump take fresh
oil from a tank located in the fuselage of the machine; one of these
delivers oil to the cam shaft, and one delivers to the crankshaft;
this fresh oil mixes with the used oil, returns to the base, and back
to the main large oil pump cylinders. By means of these small pump
pistons a constant quantity of oil is kept in the motor, and the oil
is continually being freshened by means of the new oil coming in. All
the oil pipes are very securely fastened to the lower half of the crank
case, and some cooling of the oil is effected by air passing through
channels cast in the crank case on its way to the carburettor.
A light steel manifold serves to connect the exhaust ports of the
cylinders to the main exhaust pipe, which is inclined about 25 degrees
from vertical and is arranged to give on to the atmosphere just over
the top of the upper wing of the aeroplane.
As regards carburation, an automatic air valve surrounds the throat of
the carburettor, maintaining normal composition of mixture. A small jet
is fitted for starting and running without load. The channels cast in
the crank chamber, already alluded to in connection with oil-cooling,
serve to warm the air before it reaches the carburettor, of which the
body is water-jacketed.
Ignition of the engine is by means of two Bosch Z H 6 magnetos, driven
at a speed of 2,175 revolutions per minute when the engine is running
at its normal speed of 1,450 revolutions. The maximum advance of spark
is 12 mm., or 32 degrees before the top dead centre, and the firing
order of the cylinders is 1, 5, 3, 6, 2, 4.
The radiator fitted to this engine, together with the water-jackets,
has a capacity of 25 litres of water, it is rectangular in shape, and
is normally tilted at an angle of 30 degrees from vertical. Its weight
is 26 kg., and it offers but slight head resistance in flight.
The radial type of engine, neglected altogether in Germany, was brought
to a very high state of prefection at the end of the War period by
British makers. Two makes, the Cosmos Engineering Company’s ‘Jupiter’
and ‘Lucifer,’ and the A.B.C. ‘Wasp II’ and ‘Dragon Fly 1A’ require
special mention for their light weight and reliability on trials.
The Cosmos ‘Jupiter’ was--for it is no longer being made--a 450
horse-power nine-cylinder radial engine, air-cooled, with the cylinders
set in one single row; it was made both geared to reduce the propeller
revolutions relatively to the crankshaft revolutions, and ungeared;
the normal power of the geared type was 450 horse-power, and the total
weight of the engine, including carburettors, magnetos, etc., was only
757 lbs.; the engine speed was 1,850 revolutions per minute, and the
propeller revolutions were reduced by the gearing to 1,200. Fitted to a
‘Bristol Badger’ aeroplane, the total weight was 2,800 lbs, including
pilot, passenger, two machine-guns, and full military load; at 7,000
feet the registered speed, with corrections for density, was 137 miles
per hour; in climbing, the first 2,000 feet was accomplished in 1
minute 4 seconds; 4,000 feet was reached in 2 minutes 10 seconds; 6,000
feet was reached in 3 minutes 33 seconds, and 7,000 feet in 4 minutes
15 seconds. It was intended to modify the plane design and fit a new
propeller, in order to attain even better results, but, if trials were
made with these modifications, the results are not obtainable.
The Cosmos ‘Lucifer’ was a three-cylinder radial type engine of
100 horse-power, inverted Y design, made on the simplest possible
principles with a view to quantity production and extreme reliability.
The rated 100 horse-power was attained at 1,600 revolutions per minute,
and the cylinder dimensions were 5·75 bore by 6·25 inches stroke.
The cylinders were of aluminium and steel mixture, with aluminium
heads; overhead valves, operated by push-rods on the front side of
the cylinders, were fitted, and a simple reducing gear ran them at
half engine speed. The crank case was a circular aluminium casting,
the engine being attached to the fuselage of the aeroplane by a
circular flange situated at the back of the case; propeller shaft and
crankshaft were integral. Dual ignition was provided, the generator
and distributors being driven off the back end of the engine and the
distributors being easily accessible. Lubrication was by means of two
pumps, one scavenging and one suction, oil being fed under pressure
from the crankshaft. A single carburettor fed all three cylinders, the
branch pipe from the carburettor to the circular ring being provided
with an exhaust heater. The total weight of the engine, ‘all on,’ was
280 lbs.
[Illustration: ‘Dragonfly’ 1 A.]
[Illustration: ‘Dragonfly’ piston assembly.]
[Illustration: ‘Dragonfly’ cylinder.]
The A.B.C. ‘Wasp II,’ made by Walton Motors, Limited, is a
seven-cylinder radial, air-cooled engine, the cylinders having a bore
of 4·75 inches and stroke 6·25 inches. The normal brake horse-power
at 1,650 revolutions is 160, and the maximum 200 at a speed of
1,850 revolutions per minute. Lubrication is by means of two rotary
pumps, one feeding through the hollow crankshaft to the crank pin,
giving centrifugal feed to big end and thence splash oiling, and
one feeding to the nose of the engine, dropping on to the cams and
forming a permanent sump for the gears on the bottom of the engine
nose. Two carburettors are fitted, and two two-spark magnetos, running
at one and three-quarters engine speed. The total weight of this
engine is 350 lbs., or 1·75 lbs. per horse-power. Oil consumption at
1,850 revolutions is ·03 pints per horse-power per hour, and petrol
consumption is ·56 pints per horse-power per hour. The engine thus
shows as very economical in consumption, as well as very light in
weight.
The A.B.C. ‘Dragon Fly 1A’ is a nine-cylinder radial engine having
one overhead inlet and two overhead exhaust valves per cylinder. The
cylinder dimensions are 5·5 inches bore by 6·5 inches stroke, and
the normal rate of speed, 1,650 revolutions per minute, gives 340
horse-power. The oiling is by means of two pumps, the system being
practically identical with that of the ‘Wasp II.’ Oil consumption is
·021 pints per brake horse-power per hour, and petrol consumption ·56
pints--the same as that of the ‘Wasp II.’ The weight of the complete
engine, including propeller boss, is 600 lbs., or 1·765 lbs. per
horse-power.
These A.B.C. radials have proved highly satisfactory on tests, and
their extreme simplicity of design and reliability commend them as
engineering products and at the same time demonstrate the value,
for aero work, of the air-cooled radial design--when this latter
is accompanied by sound workmanship. These and the Cosmos engines
represent the minimum of weight per horse-power yet attained, together
with a practicable degree of reliability, in radial and probably any
aero engine design.
APPENDIX A
GENERAL MENSIER’s REPORT ON THE TRIALS OF CLEMENT ADER’S ‘AVION.’
PARIS, _October 21, 1897_.
_Report on the trials of M. Clement Ader’s aviation apparatus._
M. Ader having notified the Minister of War by letter, July 21, 1897,
that the Apparatus of Aviation which he had agreed to build under the
conditions set forth in the convention of July 24th, 1894, was ready,
and therefore requesting that trials be undertaken before a Committee
appointed for this purpose as per the decision of August 4th, the
Committee was appointed as follows:--
Division General Mensier, Chairman; Division General Delambre,
Inspector General of the Permanent Works of Coast Defence, Member of
the Technical Committee of the Engineering Corps; Colonel Laussedat,
Director of the Conservatoire des Arts et Métiers; Sarrau, Member of
the Institute, Professor of Mechanical Engineering at the Polytechnic
School; Leaute, Member of the Institute, Professor of Mechanical
Engineering at the Polytechnique School.
Colonel Laussedat gave notice at once that his health and work as
Director of the Conservatoire des Arts et Métiers did not permit him
to be a member of the Committee; the Minister therefore accepted his
resignation on September 24th, and decided not to replace him.
Later on, however, on the request of the Chairman of the Committee,
the Minister appointed a new member, General Grillon, commanding the
Engineer Corps of the Military Government of Paris.
To carry on the trials which were to take place at the camp of Satory,
the Minister ordered the Governor of the Military Forces of Paris to
requisition from the Engineer Corps, on the request of the Chairman of
the Committee, the men necessary to prepare the grounds at Satory.
After an inspection made on the 16th an aerodrome was chosen. M. Ader’s
idea was to have it of circular shape with a width of 40 metres and an
average diameter of 450 metres. The preliminary work, laying out the
grounds, interior and exterior circumference, etc., was finished at the
end of August; the work of smoothing off the grounds began September
1st with forty-five men and two rollers, and was finished on the day of
the first tests, October 12th.
The first meeting of the Committee was held August 18th in M. Ader’s
workshop; the object being to demonstrate the machine to the Committee
and give all the information possible on the tests that were to be
held. After a careful examination and after having heard all the
explanations by the inventor which were deemed useful and necessary,
the Committee decided that the apparatus seemed to be built with a
perfect understanding of the purpose to be fulfilled as far as one
could judge from a study of the apparatus at rest; they therefore
authorised M. Ader to take the machine apart and carry it to the camp
at Satory so as to proceed with the trials.
By letter of August 19th the Chairman made report to the Minister of
the findings of the Committee.
The work on the grounds having taken longer than was anticipated,
the Chairman took advantage of this delay to call the Committee
together for a second meeting, during which M. Ader was to run the two
propulsive screws situated at the forward end of the apparatus.
The meeting was held October 2nd. It gave the Committee an opportunity
to appreciate the motive power in all its details; firebox, boiler,
engine, under perfect control, absolute condensation, automatic fuel
and feed of the liquid to be vaporised, automatic lubrication and
scavenging; everything, in a word, seemed well designed and executed.
The weights in comparison with the power of the engine realised
a considerable advance over anything made to date, since the two
engines weighed together realised 42 kg., the firebox and boiler 60
kg., the condenser 15 kg., or a total of 117 kg. for approximately 40
horse-power or a little less than 3 kg. per horse-power.
One of the members summed up the general opinion by saying: ‘Whatever
may be the result from an aviation point of view, a result which could
not be foreseen for the moment, it was nevertheless proven that from
a mechanical point of view M. Ader’s apparatus was of the greatest
interest and real ingeniosity. He expressed a hope that in any case the
machine would not be lost to science.’
The second experiment in the workshop was made in the presence of the
Chairman, the purpose being to demonstrate that the wings, having a
spread of 17 metres, were sufficiently strong to support the weight
of the apparatus. With this object in view, 14 sliding supports were
placed under each one of these, representing imperfectly the manner
in which the wings would support the machine in the air; by gradually
raising the supports with the slides, the wheels on which the machine
rested were lifted from the ground. It was evident at that time
that the members composing the skeleton of the wings supported the
apparatus, and it was quite evident that when the wings were supported
by the air on every point of their surface, the stress would be better
equalised than when resting on a few supports, and therefore the
resistance to breakage would be considerably greater.
After this last test, the work on the ground being practically
finished, the machine was transported to Satory, assembled and again
made ready for trial.
At first M. Ader was to manœuvre the machine on the ground at a
moderate speed, then increase this until it was possible to judge
whether there was a tendency for the machine to rise; and it was only
after M. Ader had acquired sufficient practice that a meeting of the
Committee was to be called to be present at the first part of the
trials; namely, volutions of the apparatus on the ground.
The first test took place on Tuesday, October 12th, in the presence of
the Chairman of the Committee. It had rained a good deal during the
night and the clay track would have offered considerable resistance to
the rolling of the machine; furthermore, a moderate wind was blowing
from the south-west, too strong during the early part of the afternoon
to allow of any trials.
Toward sunset, however, the wind having weakened, M. Ader decided to
make his first trial; the machine was taken out of its hangar, the
wings were mounted and steam raised. M. Ader in his seat had, on each
side of him, one man to the right and one to the left, whose duty was
to rectify the direction of the apparatus in the event that the action
of the rear wheel as a rudder would not be sufficient to hold the
machine in a straight course.
At 5.25 p.m. the machine was started, at first slowly and then at an
increased speed; after 250 or 300 metres, the two men who were being
dragged by the apparatus were exhausted and forced to fall flat on
the ground in order to allow the wings to pass over them, and the
trip around the track was completed, a total of 1,400 metres, without
incident, at a fair speed, which could be estimated to be from 300
to 400 metres per minute. Notwithstanding M. Ader’s inexperience,
this being the first time that he had run his apparatus, he followed
approximately the chalk line which marked the centre of the track and
he stopped at the exact point from which he started.
The marks of the wheels on the ground, which was rather soft, did not
show up very much, and it was clear that a part of the weight of the
apparatus had been supported by the wings, though the speed was only
about one-third of what the machine could do had M. Ader used all its
motive power; he was running at a pressure of from 3 to 4 atmospheres,
when he could have used 10 to 12.
This first trial, so fortunately accomplished, was of great importance;
it was the first time that a comparatively heavy vehicle (nearly 400
kg., including the weight of the operator, fuel, and water) had been
set in motion by a tractive apparatus, using the air solely as a
propelling medium. The favourable report turned in by the Committee
after the meeting of October 2nd was found justified by the results
demonstrated on the grounds, and the first problem of aviation, namely,
the creation of efficient motive power, could be considered as solved,
since the propulsion of the apparatus in the air would be a great deal
easier than the traction on the ground, provided that the second part
of the problem, the sustaining of the machine in the air, would be
realised.
The next day, Wednesday the 13th, no further trials were made on
account of the rain and wind.
On Thursday the 14th the Chairman requested that General Grillon, who
had just been appointed a member of the Committee, accompany him so as
to have a second witness.
The weather was fine, but a fairly strong, gusty wind was blowing from
the south. M. Ader explained to the two members of the Committee the
danger of these gusts, since at two points of the circumference the
wind would strike him sideways. The wind was blowing in the direction
A B, the apparatus starting from C, and running in the direction shown
by the arrow. The first dangerous spot would be at B. The apparatus
had been kept in readiness in the event of the wind dying down. Toward
sunset the wind seemed to die down, as it had done on the evening of
the 12th. M. Ader hesitated, which, unfortunately, further events only
justified, but decided to make a new trial.
At the start, which took place at 5.15 p.m., the apparatus, having
the wind in the rear, seemed to run at a fairly regular speed; it
was, nevertheless, easy to note from the marks of the wheels on the
ground that the rear part of the apparatus had been lifted and that
the rear wheel, being the rudder, had not been in constant contact
with the ground. When the machine came to the neighbourhood of B, the
two members of the Committee saw the machine swerve suddenly out of
the track in a semicircle, lean over to the right and finally stop.
They immediately proceeded to the point where the accident had taken
place and endeavoured to find an explanation for the same. The Chairman
finally decided as follows:--
M. Ader was the victim of a gust of wind which he had feared as he
explained before starting out; feeling himself thrown out of his
course, he tried to use the rudder energetically, but at that time the
rear wheel was not in contact with the ground, and therefore did not
perform its function; the canvas rudder, which had as its purpose the
manœuvring of the machine in the air, did not have sufficient action
on the ground. It would have been possible without any doubt to react
by using the propellers at unequal speed, but M. Ader, being still
inexperienced, had not thought of this. Furthermore, he was thrown out
of his course so quickly that he decided, in order to avoid a more
serious accident, to stop both engines. This sudden stop produced the
half-circle already described and the fall of the machine on its side.
The damage to the machine was serious; consisting at first sight of the
rupture of both propellers, the rear left wheel and the bending of the
left wing tip. It will only be possible to determine after the machine
is taken apart whether the engine, and more particularly the organs of
transmission, have been put out of line.
Whatever the damage may be, though comparatively easy to repair, it
will take a certain amount of time, and taking into consideration the
time of year it is evident that the tests will have to be adjourned for
the present.
As has been said in the above report, the tests, though prematurely
interrupted, have shown results of great importance, and though the
final results are hard to foresee, it would seem advisable to continue
the trials. By waiting for the return of spring there will be plenty
of time to finish the tests and it will not be necessary to rush
matters, which was a partial cause of the accident. The Chairman of the
Committee personally has but one hope, and that is that a decision be
reached accordingly.
Division General,
Chairman of the Committee,
MENSIER.
BOULOGNE-SUR-SEINE, _October 21st, 1897_.
_Annex to the Report of October 21st._
General Grillon, who was present at the trials of the 14th, and who
saw the report relative to what happened during that day, made the
following observations in writing, which are reproduced herewith
in quotation marks. The Chairman of the Committee does not agree
with General Grillon and he answers these observations paragraph by
paragraph.
1. ‘If the rear wheel (there is only one of these) left but
intermittent tracks on the ground, does that prove that the machine has
a tendency to rise when running at a certain speed?’
_Answer._--This does not prove anything in any way, and I was very
careful not to mention this in my report, this point being exactly
what was needed and that was not demonstrated during the two tests made
on the grounds.
‘Does not this unequal pressure of the two pair of wheels on the ground
show that the centre of gravity of the apparatus is placed too far
forward and that under the impulse of the propellers the machine has a
tendency to tilt forward, due to the resistance of the air?’
_Answer._--The tendency of the apparatus to rise from the rear when it
was running with the wind seemed to be brought about by the effects of
the wind on the huge wings, having a spread of 17 metres, and I believe
that when the machine would have faced the wind the front wheels would
have been lifted.
During the trials of October 12th, when a complete circuit of the track
was accomplished without incidents, as I and Lieut. Binet witnessed,
there was practically no wind. I was therefore unable to verify whether
during this circuit the two front wheels or the rear wheel were in
constant contact with the ground, because when the trial was over
it was dark (it was 5.30) and the next day it was impossible to see
anything because it had rained during the night and during Wednesday
morning. But what would prove that the rear wheel was in contact with
the ground at all times is the fact that M. Ader, though inexperienced,
did not swerve from the circular track, which would prove that he
steered pretty well with his rear wheel--this he could not have done if
he had been in the air.
In the tests of the 12th, the speed was at least as great as on the
14th.
2. ‘It would seem to me that if M. Ader thought that his rear wheels
were off the ground he should have used his canvas rudder in order to
regain his proper course; this was the best way of causing the machine
to rotate, since it would have given an angular motion to the front
axle.’
_Answer._--I state in my report that the canvas rudder whose object
was the manœuvre of the apparatus in the air could have no effect on
the apparatus on the ground, and to convince oneself of this point
it is only necessary to consider the small surface of this canvas
rudder compared with the mass to be handled on the ground, a weight of
approximately 400 kg. According to my idea, and as I have stated in my
report, M. Ader should have steered by increasing the speed on one of
his propellers and slowing down the other. He admitted afterward that
this remark was well founded, but that he did not have time to think of
it owing to the suddenness of the accident.
3. ‘When the apparatus fell on its side it was under the sole influence
of the wind, since M. Ader had stopped the machine. Have we not a
result here which will always be the same when the machine comes to
the ground, since the engines will always have to be stopped or slowed
down when coming to the ground? Here seems to be a bad defect of the
apparatus under trial.’
_Answer._--I believe that the apparatus fell on its side after coming
to a stop, not on account of the wind, but because the semicircle
described was on rough ground and one of the wheels had collapsed.
MENSIER.
_October 27th, 1897._
APPENDIX B
_Specification and Claims of Wright Patent, No. 821393. Filed March
23rd, 1903. Issued May 22nd, 1906. Expires May 22nd, 1923._
To all whom it may concern.
Be it known that we, Orville Wright and Wilbur Wright, citizens of the
United States, residing in the city of Dayton, county of Montgomery,
and State of Ohio, have invented certain new and useful Improvements in
Flying Machines, of which the following is a specification.
Our invention relates to that class of flying machines in which the
weight is sustained by the reactions resulting when one or more
aeroplanes are moved through the air edgewise at a small angle of
incidence, either by the application of mechanical power or by the
utilisation of the force of gravity.
The objects of our invention are to provide means for maintaining or
restoring the equilibrium or lateral balance of the apparatus, to
provide means for guiding the machine both vertically and horizontally,
and to provide a structure combining lightness, strength, convenience
of construction and certain other advantages which will hereinafter
appear.
To these ends our invention consists in certain novel features, which
we will now proceed to describe and will then particularly point out in
the claims.
In the accompanying drawings, Figure 1 is a perspective view of an
apparatus embodying our invention in one form. Fig. 2 is a plan view of
the same, partly in horizontal section and partly broken away. Fig. 3
is a side elevation, and Figs. 4 and 5 are detail views, of one form of
flexible joint for connecting the upright standards with the aeroplanes.
In flying machines of the character to which this invention relates
the apparatus is supported in the air by reason of the contact between
the air and the under surface of one or more aeroplanes, the contact
surface being presented at a small angle of incidence to the air.
The relative movements of the air and aeroplane may be derived from
the motion of the air in the form of wind blowing in the direction
opposite to that in which the apparatus is travelling or by a combined
downward and forward movement of the machine, as in starting from an
elevated position or by combination of these two things, and in either
case the operation is that of a soaring-machine, while power applied
to the machine to propel it positively forward will cause the air to
support the machine in a similar manner. In either case owing to the
varying conditions to be met there are numerous disturbing forces which
tend to shift the machine from the position which it should occupy to
obtain the desired results. It is the chief object of our invention to
provide means for remedying this difficulty, and we will now proceed
to describe the construction by means of which these results are
accomplished.
[Illustration: Patented May 22nd, 1905. O. & W. Wright Flying Machine.]
In the accompanying drawing we have shown an apparatus embodying our
invention in one form. In this illustrative embodiment the machine is
shown as comprising two parallel superposed aeroplanes, 1 and 2 may
be embodied in a structure having a single aeroplane Each aeroplane
is of considerably greater width from side to side than from front to
rear. The four corners of the upper aeroplane are indicated by the
reference letters _a_, _b_, _c_, and _d_, while the corresponding
corners of the lower aeroplane 2 are indicated by the reference letters
_e_, _f_, _g_, and _h_. The marginal lines _a b_ and _e f_ indicate
the front edges of the aeroplanes, the lateral margins of the upper
aeroplane are indicated, respectively, by the lines _a d_ and _b c_,
the lateral margins of the lower aeroplane are indicated, respectively,
by the lines _e h_ and _f g_, while the rear margins of the upper and
lower aeroplanes are indicated, respectively, by the lines _c d_ and _g
h_.
Before proceeding to a description of the fundamental theory of
operation of the structure we will first describe the preferred mode of
constructing the aeroplanes and those portions of the structure which
serve to connect the two aeroplanes.
Each aeroplane is formed by stretching cloth or other suitable fabric
over a frame composed of two parallel transverse spars 3, extending
from side to side of the machine, their ends being connected by bows
4, extending from front to rear of the machine. The front and rear
spars 3 of each aeroplane are connected by a series of parallel ribs
5, which preferably extend somewhat beyond the rear spar, as shown.
These spars, bows, and ribs are preferably constructed of wood having
the necessary strength, combined with lightness and flexibility. Upon
this framework the cloth which forms the supporting surface of the
aeroplane is secured, the frame being enclosed in the cloth. The cloth
for each aeroplane previous to its attachment to its frame is cut
on the bias and made up into a single piece approximately the size
and shape of the aeroplane, having the threads of the fabric arranged
diagonally to the transverse spars and longitudinal ribs, as indicated
at 6 in Fig. 2. Thus the diagonal threads of the cloth form truss
systems with the spars and ribs, the threads constituting the diagonal
members. A hem is formed at the rear edge of the cloth to receive a
wire 7, which is connected to the ends of the rear spar and supported
by the rearwardly-extending ends of the longitudinal ribs 5, thus
forming a rearwardly-extending flap or portion of the aeroplane. This
construction of the aeroplane gives a surface which has very great
strength to withstand lateral and longitudinal strains, at the same
time being capable of being bent or twisted in the manner hereinafter
described.
When two aeroplanes are employed, as in the construction illustrated,
they are connected together by upright standards 8. These standards are
substantially rigid, being preferably constructed of wood and of equal
length, equally spaced along the front and rear edges of the aeroplane,
to which they are connected at their top and bottom ends by hinged
joints or universal joints of any suitable description. We have shown
one form of connection which may be used for this purpose in Figs. 4
and 5 of the drawings. In this construction each end of the standard 8
has secured to it an eye 9, which engages with a hook 10, secured to a
bracket plate 11, which latter plate is in turn fastened to the spar 3.
Diagonal braces or stay-wires 12 extend from each end of each standard
to the opposite ends of the adjacent standards, and as a convenient
mode of attaching these parts I have shown a hook 13 made integral
with the hook 10 to receive the end of one of the stay-wires, the other
stay-wire being mounted on the hook 10. The hook 13 is shown as bent
down to retain the stay-wire in connection to it, while the hook 10 is
shown as provided with a pin 14 to hold the staywire 12 and eye 9 in
position thereon. It will be seen that this construction forms a truss
system which gives the whole machine great transverse rigidity and
strength, while at the same time the jointed connections of the parts
permit the aeroplanes to be bent or twisted in the manner which we will
now proceed to describe.
15 indicates a rope or other flexible connection extending lengthwise
of the front of the machine above the lower aeroplane, passing under
pulleys or other suitable guides 16 at the front corners _e_ and _f_
of the lower aeroplane, and extending thence upward and rearward to
the upper rear corners _c_ and _d_, of the upper aeroplane, where
they are attached, as indicated at 17. To the central portion of the
rope there is connected a laterally-movable cradle 18, which forms a
means for moving the rope lengthwise in one direction or the other,
the cradle being movable toward either side of the machine. We have
devised this cradle as a convenient means for operating the rope 15,
and the machine is intended to be generally used with the operator
lying face downward on the lower aeroplane, with his head to the front,
so that the operator’s body rests on the cradle, and the cradle can
be moved laterally by the movements of the operator’s body. It will
be understood, however, that the rope 15 may be manipulated in any
suitable manner.
19 indicates a second rope extending transversely of the machine along
the rear edge of the body portion of the lower aeroplane, passing
under suitable pulleys or guides 20 at the rear corners _g_ and _h_ of
the lower aeroplane and extending thence diagonally upward to the front
corners _a_ and _b_ of the upper aeroplane, where its ends are secured
in any suitable manner, as indicated at 21.
Considering the structure so far as we have now described it, and
assuming that the cradle 18 be moved to the right in Figs. 1 and 2,
as indicated by the arrows applied to the cradle in Fig. 1 and by the
dotted lines in Fig. 2, it will be seen that that portion of the rope
15 passing under the guide pulley at the corner _e_ and secured to the
corner _d_ will be under tension, while slack is paid out throughout
the other side or half of the rope 15. The part of the rope 15 under
tension exercises a downward pull upon the rear upper corner _d_ of
the structure and an upward pull upon the front lower corner _e_, as
indicated by the arrows. This causes the corner _d_ to move downward
and the corner _e_ to move upward. As the corner _e_ moves upward it
carries the corner _a_ upward with it, since the intermediate standard
8 is substantially rigid and maintains an equal distance between the
corners _a_ and _e_ at all times. Similarly, the standard 8, connecting
the corners _d_ and _h_, causes the corner _h_ to move downward in
unison with the corner _d_. Since the corner _a_ thus moves upward and
the corner _h_ moves downward, that portion of the rope 19 connected
to the corner _a_ will be pulled upward through the pulley 20 at the
corner _h_, and the pull thus exerted on the rope 19 will pull the
corner _b_ on the other wise of the machine downward and at the same
time pull the corner _g_ at said other side of the machine upward.
This results in a downward movement of the corner _b_ and an upward
movement of the corner _c_. Thus it results from a lateral movement of
the cradle 18 to the right in Fig. 1 that the lateral margins _a d_ and
_e h_ at one side of the machine are moved from their normal positions
in which they lie in the normal planes of their respective aeroplanes,
into angular relations with said normal planes, each lateral margin
on this side of the machine being raised above said normal plane at
its forward end and depressed below said normal plane at its rear end,
said lateral margins being thus inclined upward and forward. At the
same time a reverse inclination is imparted to the lateral margins
_b c_ and _f g_ at the other side of the machine, their inclination
being downward and forward. These positions are indicated in dotted
lines in Fig. 1 of the drawings. A movement of the cradle 18 in the
opposite direction from its normal position will reverse the angular
inclination of the lateral margins of the aeroplanes in an obvious
manner. By reason of this construction it will be seen that with the
particular mode of construction now under consideration it is possible
to move the forward corner of the lateral edges of the aeroplane on
one side of the machine either above or below the normal planes of the
aeroplanes, a reverse movement of the forward corners of the lateral
margins on the other side of the machine occurring simultaneously.
During this operation each aeroplane is twisted or distorted around
a line extending centrally across the same from the middle of one
lateral margin to the middle of the other lateral margin, the twist
due to the moving of the lateral margins to different angles extending
across each aeroplane from side to side, so that each aeroplane surface
is given a helicoidal warp or twist. We prefer this construction and
mode of operation for the reason that it gives a gradually increasing
angle to the body of each aeroplane from the centre longitudinal line
thereof outward to the margin, thus giving a continuous surface on each
side of the machine, which has a gradually increasing or decreasing
angle of incidence from the centre of the machine to either side. We
wish it to be understood, however, that our invention is not limited
to this particular construction, since any construction whereby the
angular relations of the lateral margins of the aeroplanes may be
varied in opposite directions with respect to the normal planes of said
aeroplanes comes within the scope of our invention. Furthermore, it
should be understood that while the lateral margins of the aeroplanes
move to different angular positions with respect to or above and below
the normal planes of said aeroplanes, it does not necessarily follow
that these movements bring the opposite lateral edges to different
angles respectively above and below a horizontal plane, since the
normal planes of the bodies of the aeroplanes are inclined to the
horizontal when the machine is in flight, said inclination being
downward from front to rear, and while the forward corners on one
side of the machine may be depressed below the normal planes of the
bodies of the aeroplanes said depression is not necessarily sufficient
to carry them below the horizontal planes passing through the rear
corners on that side. Moreover, although we prefer to so construct the
apparatus that the movements of the lateral margins on the opposite
sides of the machine are equal in extent and opposite in direction,
yet our invention is not limited to a construction producing this
result, since it may be desirable under certain circumstances to move
the lateral margins on one side of the machine just described without
moving the lateral margins on the other side of the machine to an
equal extent in the opposite direction. Turning now to the purpose
of this provision for moving the lateral margins of the aeroplanes
in the manner described, it should be premised that owing to various
conditions of wind pressure and other causes the body of the machine
is apt to become unbalanced laterally, one side tending to sink and
the other side tending to rise, the machine turning around its central
longitudinal axis. The provision which we have just described enables
the operator to meet this difficulty and preserve the lateral balance
of the machine. Assuming that for some cause that side of the machine
which lies to the left of the observer in Figs. 1 and 2 has shown a
tendency to drop downward, a movement of the cradle 18 to the right of
said figures, as hereinbefore assumed, will move the lateral margins of
the aeroplanes in the manner already described, so that the margins _a
d_ and _e h_ will be inclined downward and rearward, and the lateral
margins _b c_ and _f g_ will be inclined upward and rearward with
respect to the normal planes of the bodies of the aeroplanes. With
the parts of the machine in this position it will be seen that the
lateral margins _a d_ and _e h_ present a larger angle of incidence
to the resisting air, while the lateral margins on the other side of
the machine present a smaller angle of incidence. Owing to this fact,
the side of the machine presenting the larger angle of incidence will
tend to lift or move upward, and this upward movement will restore the
lateral balance of the machine. When the other side of the machine
tends to drop, a movement of the cradle 18 in the reverse direction
will restore the machine to its normal lateral equilibrium. Of course,
the same effect will be produced in the same way in the case of a
machine employing only a single aeroplane.
In connection with the body of the machine as thus operated we employ a
vertical rudder or tail 22, so supported as to turn around a vertical
axis. This rudder is supported at the rear ends on supports or arms
23, pivoted at their forward ends to the rear margins of the upper
and lower aeroplanes, respectively. These supports are preferably
V-shaped, as shown, so that their forward ends are comparatively
widely separated, their pivots being indicated at 24. Said supports
are free to swing upward at their free rear ends, as indicated in
dotted lines in Fig. 3, their downward movement being limited in any
suitable manner. The vertical pivots of the rudder 22 are indicated
at 25, and one of these pivots has mounted thereon a sheave or pulley
26, around which passes a tiller-rope 27, the ends of which are
extended out laterally and secured to the rope 19 on opposite sides
of the central point of said rope. By reason of this construction
the lateral shifting of the cradle 18 serves to turn the rudder to
one side or the other of the line of flight. It will be observed in
this connection that the construction is such that the rudder will
always be so turned as to present its resisting surface on that side
of the machine on which the lateral margins of the aeroplanes present
the least angle of resistance. The reason of this construction is
that when the lateral margins of the aeroplanes are so turned in
the manner hereinbefore described as to present different angles of
incidence to the atmosphere, that side presenting the largest angle of
incidence, although being lifted or moved upward in the manner already
described, at the same time meets with an increased resistance to its
forward motion, while at the same time the other side of the machine,
presenting a smaller angle of incidence, meets with less resistance
to its forward motion and tends to move forward more rapidly than the
retarded side. This gives the machine a tendency to turn around its
vertical axis, and this tendency if not properly met will not only
change the direction of the front of the machine, but will ultimately
permit one side thereof to drop into a position vertically below the
other side with the aeroplanes in vertical position, thus causing the
machine to fall. The movement of the rudder, hereinbefore described,
prevents this action, since it exerts a retarding influence on that
side of the machine which tends to move forward too rapidly and
keeps the machine with its front properly presented to the direction
of flight and with its body properly balanced around its central
longitudinal axis. The pivoting of the supports 23 so as to permit
them to swing upward prevents injury to the rudder and its supports in
case the machine alights at such an angle as to cause the rudder to
strike the ground first, the parts yielding upward, as indicated in
dotted lines in Fig. 3, and thus preventing injury or breakage. We wish
it to be understood, however, that we do not limit ourselves to the
particular description of rudder set forth, the essential being that
the rudder shall be vertical and shall be so moved as to present its
resisting surface on that side of the machine which offers the least
resistance to the atmosphere, so as to counteract the tendency of the
machine to turn around a vertical axis when the two sides thereof offer
different resistances to the air.
From the central portion of the front of the machine struts 28 extend
horizontally forward from the lower aeroplane, and struts 29 extend
downward and forward from the central portion of the upper aeroplane,
their front ends being united to the struts 28, the forward extremities
of which are turned up, as indicated at 30. These struts 28 and 29
form truss-skids projecting in front of the whole frame of the machine
and serving to prevent the machine from rolling over forward when it
alights. The struts 29 serve to brace the upper portion of the main
frame and resist its tendency to move forward after the lower aeroplane
has been stopped by its contact with the earth, thereby relieving the
rope 19 from undue strain, for it will be understood that when the
machine comes into contact with the earth, further forward movement of
the lower portion thereof being suddenly arrested, the inertia of the
upper portion would tend to cause it to continue to move forward if
not prevented by the struts 29, and this forward movement of the upper
portion would bring a very violent strain upon the rope 19, since it
is fastened to the upper portion at both of its ends, while its lower
portion is connected by the guides 20 to the lower portion. The struts
28 and 29 also serve to support the front or horizontal rudder, the
construction of which we will now proceed to describe.
The front rudder 31 is a horizontal rudder having a flexible body, the
same consisting of three stiff cross-pieces or sticks 32, 33, and 34,
and the flexible ribs 35, connecting said cross-pieces and extending
from front to rear. The frame thus provided is covered by a suitable
fabric stretched over the same to form the body of the rudder. The
rudder is supported from the struts 29 by means of the intermediate
cross-piece 32, which is located near the centre of pressure slightly
in front of a line equidistant between the front and rear edges of the
rudder, the cross-piece 32 forming the pivotal axis of the rudder, so
as to constitute a balanced rudder. To the front edge of the rudder
there are connected springs 36, which springs are connected to the
upturned ends 30 of the struts 28, the construction being such that
said springs tend to resist any movement either upward or downward of
the front edge of the horizontal rudder. The rear edge of the rudder
lies immediately in front of the operator and may be operated by him
in any suitable manner. We have shown a mechanism for this purpose
comprising a roller or shaft 37, which may be grasped by the operator
so as to turn the same in either direction. Bands 38 extend from the
roller 37 forward to and around a similar roller or shaft 39, both
rollers or shafts being supported in suitable bearings on the struts
28. The forward roller or shaft has rearwardly-extending arms 40,
which are connected by links 41 with the rear edge of the rudder 31.
The normal position of the rudder 31 is neutral or substantially
parallel with the aeroplanes 1 and 2; but its rear edge may be moved
upward or downward, so as to be above or below the normal plane of
said rudder through the mechanism provided for that purpose. It will
be seen that the springs 36 will resist any tendency of the forward
edge of the rudder to move in either direction, so that when force is
applied to the rear edge of said rudder the longitudinal ribs 35 bend,
and the rudder thus presents a concave surface to the action of the
wind either above or below its normal plane, said surface presenting
a small angle of incidence at its forward portion and said angle of
incidence rapidly increasing toward the rear. This greatly increases
the efficiency of the rudder as compared with a plane surface of equal
area. By regulating the pressure on the upper and lower sides of the
rudder through changes of angle and curvature in the manner described a
turning movement of the main structure around its transverse axis may
be effected, and the course of the machine may thus be directed upward
or downward at the will of the operator and the longitudinal balance
thereof maintained.
Contrary to the usual custom, we place the horizontal rudder in front
of the aeroplanes at a negative angle and employ no horizontal tail at
all. By this arrangement we obtain a forward surface which is almost
entirely free from pressure under ordinary conditions of flight, but
which even if not moved at all from its original position becomes
an efficient lifting surface whenever the speed of the machine is
accidentally reduced very much below the normal, and thus largely
counteracts that backward travel of the centre of pressure on the
aeroplanes which has frequently been productive of serious injuries by
causing the machine to turn downward and forward and strike the ground
head-on. We are aware that a forward horizontal rudder of different
construction has been used in combination with a supporting surface
and a rear horizontal rudder; but this combination was not intended
to effect and does not effect the object which we obtain by the
arrangement hereinbefore described.
We have used the term ‘aeroplane’ in this specification and the
appended claims to indicate the supporting surface or supporting
surfaces by means of which the machine is sustained in the air, and
by this term we wish to be understood as including any suitable
supporting surface which normally is substantially flat, although,
of course, when constructed of cloth or other flexible fabric, as we
prefer to construct them, these surfaces may receive more or less
curvature from the resistance of the air, as indicated in Fig. 3.
We do not wish to be understood as limiting ourselves strictly to the
precise details of construction hereinbefore described and shown in
the accompanying drawings, as it is obvious that these details may be
modified without departing from the principles of our invention. For
instance, while we prefer the construction illustrated in which each
aeroplane is given a twist along its entire length in order to set its
opposite lateral margins at different angles, we have already pointed
out that our invention is not limited to this form of construction,
since it is only necessary to move the lateral marginal portions, and
where these portions alone are moved only those upright standards which
support the movable portion require flexible connections at their ends.
Having thus fully described our invention, what we claim as new, and
desire to secure by Letters Patent, is:--
1. In a flying machine, a normally flat aeroplane having lateral
marginal portions capable of movement to different positions above or
below the normal plane of the body of the aeroplane, such movement
being about an axis transverse to the line of flight, whereby said
lateral marginal portions may be moved to different angles relatively
to the normal plane of the body of the aeroplane, so as to present to
the atmosphere different angles of incidence, and means for so moving
said lateral marginal portions, substantially as described.
2. In a flying machine, the combination, with two normally parallel
aeroplanes, superposed the one above the other, of upright standards
connecting said planes at their margins, the connections between the
standards and aeroplanes at the lateral portions of the aeroplanes
being by means of flexible joints, each of said aeroplanes having
lateral marginal portions capable of movement to different positions
above or below the normal plane of the body of the aeroplane, such
movement being about an axis transverse to the line of flight, whereby
said lateral marginal portions may be moved to different angles
relatively to the normal plane of the body of the aeroplane, so as to
present to the atmosphere different angles of incidence, the standards
maintaining a fixed distance between the portions of the aeroplanes
which they connect, and means for imparting such movement to the
lateral marginal portions of the aeroplanes, substantially as described.
3. In a flying machine, a normally flat aeroplane having lateral
marginal portions capable of movement to different positions above or
below the normal plane of the body of the aeroplane, such movement
being about an axis transverse to the line of flight, whereby said
lateral marginal portions may be moved to different angles relatively
to the normal plane of the body of the aeroplane, and also to different
angles relatively to each other, so as to present to the atmosphere
different angles of incidence, and means for simultaneously imparting
such movement to said lateral marginal portions, substantially as
described.
4. In a flying machine, the combination, with parallel superposed
aeroplanes, each having lateral marginal portions capable of movement
to different positions above or below the normal plane of the body
of the aeroplane, such movement being about an axis transverse to the
line of flight, whereby said lateral marginal portions may be moved
to different angles relatively to the normal plane of the body of the
aeroplane, and to different angles relatively to each other, so as to
present to the atmosphere different angles of incidence, of uprights
connecting said aeroplanes at their edges, the uprights connecting the
lateral portions of the aeroplanes being connected with said aeroplanes
by flexible joints, and means for simultaneously imparting such
movement to said lateral marginal portions, the standards maintaining
a fixed distance between the parts which they connect, whereby the
lateral portions on the same side of the machine are moved to the same
angle, substantially as described.
5. In a flying machine, an aeroplane having substantially the form of a
normally flat rectangle elongated transversely to the line of flight,
in combination which means for imparting to the lateral margins of said
aeroplane a movement about an axis lying in the body of the aeroplane
perpendicular to said lateral margins, and thereby moving said lateral
margins into different angular relations to the normal plane of the
body of the aeroplane, substantially as described.
6. In a flying machine, the combination, with two superposed and
normally parallel aeroplanes, each having substantially the form of a
normally flat rectangle elongated transversely to the line of flight,
of upright standards connecting the edges of said aeroplanes to
maintain their equidistance, those standards at the lateral portions
of said aeroplanes being connected therewith by flexible joints, and
means for simultaneously imparting to both lateral margins of both
aeroplanes movement about axes which are perpendicular to said margins
and in the planes of the bodies of the respective aeroplanes, and
thereby moving the lateral margins on the opposite sides of the machine
into different angular relations to the normal planes of the respective
aeroplanes, the margins on the same side of the machine moving to the
same angle, and the margins on one side of the machine moving to an
angle different from the angle to which the margins on the other side
of the machine move, substantially as described.
7. In a flying machine, the combination, with an aeroplane, and means
for simultaneously moving the lateral portions thereof into different
angular relations to the normal plane of the body of the aeroplane and
to each other, so as to present to the atmosphere different angles
of incidence, of a vertical rudder, and means whereby said rudder is
caused to present to the wind that side thereof nearest the side of the
aeroplane having the smaller angle of incidence and offering the least
resistance to the atmosphere, substantially as described.
8. In a flying machine, the combination, with two superposed and
normally parallel aeroplanes, upright standards connecting the edges
of said aeroplanes to maintain their equidistance, those standards
at the lateral portions of said aeroplanes being connected therewith
by flexible joints, and means for simultaneously moving both lateral
portions of both aeroplanes into different angular relations to the
normal planes of the bodies of the respective aeroplanes, the lateral
portions on one side of the machine being moved to an angle different
from that to which the lateral portions on the other side of the
machine are moved, so as to present different angles of incidence at
the two sides of the machine, of a vertical rudder, and means whereby
said rudder is caused to present to the wind that side thereof nearest
the side of the aeroplanes having the smaller angle of incidence and
offering the least resistance to the atmosphere, substantially as
described.
9. In a flying machine, an aeroplane normally flat and elongated
transversely to the line of flight, in combination with means for
imparting to said aeroplane a helicoidal warp around an axis transverse
to the line of flight and extending centrally along the body of
the aeroplane in the direction of the elongation of the aeroplane,
substantially as described.
10. In a flying machine, two aeroplanes, each normally flat and
elongated transversely to the line of flight, and upright standards
connecting the edges of said aeroplanes to maintain their equidistance,
the connections between said standards and aeroplanes being by means of
flexible joints, in combination with means for simultaneously imparting
to each of said aeroplanes a helicoidal warp around an axis transverse
to the line of flight and extending centrally along the body of the
aeroplane in the direction of the aeroplane, substantially as described.
11. In a flying machine, two aeroplanes, each normally flat and
elongated transversely to the line of flight, and upright standards
connecting the edges of said aeroplanes to maintain their equidistance,
the connections between such standards and aeroplanes being by means of
flexible joints, in combination with means for simultaneously imparting
to each of said aeroplanes a helicoidal warp around an axis transverse
to the line of flight and extending centrally along the body of the
aeroplane in the direction of the elongation of the aeroplane, a
vertical rudder, and means whereby said rudder is caused to present to
the wind that side thereof nearest the side of the aeroplanes having
the smaller angle of incidence and offering the least resistance to the
atmosphere, substantially as described.
12. In a flying machine, the combination, with an aeroplane, of a
normally flat and substantially horizontal flexible rudder, and means
for curving said rudder rearwardly and upwardly or rearwardly and
downwardly with respect to its normal plane, substantially as described.
13. In a flying machine, the combination, with an aeroplane, of a
normally flat and substantially horizontal flexible rudder pivotally
mounted on an axis transverse to the line of flight near its centre,
springs resisting vertical movement of the front edge of said rudder,
and means for moving the rear edge of said rudder, above or below the
normal plane thereof, substantially as described.
14. A flying machine comprising superposed connected aeroplanes
means for moving the opposite lateral portions of said aeroplanes to
different angles to the normal planes thereof, a vertical rudder,
means for moving said vertical rudder toward that side of the machine
presenting the smaller angle of incidence and the least resistance
to the atmosphere, and a horizontal rudder provided with means for
presenting its upper or under surface to the resistance of the
atmosphere, substantially as described.
15. A flying machine comprising superposed connected aeroplanes,
means for moving the opposite lateral portions of said aeroplanes to
different angles to the normal planes thereof, a vertical rudder,
means for moving said vertical rudder toward that side of the
machine presenting the smaller angle of incidence and the least
resistance to the atmosphere, and a horizontal rudder provided with
means for presenting its upper or under surface to the resistance of
the atmosphere, said vertical rudder being located at the rear of
the machine and said horizontal rudder at the front of the machine,
substantially as described.
16. In a flying machine, the combination, with two superposed and
connected aeroplanes, of an arm extending rearward from each aeroplane,
said arms being parallel and free to swing upward at their rear ends,
and a vertical rudder pivotally mounted in the rear ends of said arms,
substantially as described.
17. A flying machine comprising two superposed aeroplanes, normally
flat but flexible, upright standards connecting the margins of said
aeroplanes, said standards being connected to said aeroplanes by
universal joints, diagonal stay-wires connecting the opposite ends of
the adjacent standards, a rope extending along the front edge of the
lower aeroplane, passing through guides at the front corners thereof,
and having its ends secured to the rear corners of the upper aeroplane,
and a rope extending along the rear edge of the lower aeroplane,
passing through guides at the rear corners thereof, and having its ends
secured to the front corners of the upper aeroplane, substantially as
described.
18. A flying machine comprising two superposed aeroplanes, normally
flat but flexible, upright standards connecting the margins of said
aeroplanes, said standards being connected to said aeroplanes by
universal joints, diagonal stay-wires connecting the opposite ends of
the adjacent standards, a rope extending along the front edge of the
lower aeroplane, passing through guides at the front corners thereof,
and having its ends secured to the rear corners of the upper aeroplane,
and a rope extending along the rear edge of the lower aeroplane,
passing through guides at the rear corners thereof, and having its ends
secured to the front corners of the upper aeroplane, in combination
with a vertical rudder, and a tiller-rope connecting said rudder
with the rope extending along the rear edge of the lower aeroplane,
substantially as described.
ORVILLE WRIGHT.
WILBUR WRIGHT.
Witnesses:
Chas. E. Taylor.
E. Earle Forrer.
APPENDIX C
_Proclamation published by the French Government on balloon ascents,
1783._
NOTICE TO THE PUBLIC! PARIS, 27TH AUGUST, 1783.
On the Ascent of balloons or globes in the air. The one in question has
been raised in Paris this day, 27th August, 1783, at 5 p.m., in the
Champ de Mars.
A Discovery has been made, which the Government deems it right to make
known, so that alarm be not occasioned to the people.
On calculating the different weights of hot air, hydrogen gas, and
common air, it has been found that a balloon filled with either of the
two former will rise toward heaven till it is in equilibrium with the
surrounding air, which may not happen until it has attained a great
height.
The first experiment was made at Annonay, in Vivarais, MM. Mongolfier,
the inventors; a globe formed of canvas and paper, 105 feet in
circumference, filled with heated air, reached an uncalculated height.
The same experiment has just been renewed in Paris before a great
crowd. A globe of taffetas or light canvas covered by elastic gum and
filled with inflammable air, has risen from the Champ de Mars, and been
lost to view in the clouds, being borne in a north-westerly direction.
One cannot foresee where it will descend.
It is proposed to repeat these experiments on a larger scale. Any
one who shall see in the sky such a globe, which resembles ‘la
lune obscurcie,’ should be aware that, far from being an alarming
phenomenon, it is only a machine that cannot possibly cause any harm,
and which will some day prove serviceable to the wants of society.
(Signed) DE SAUVIGNY.
LENOIR.
A SHORT BIBLIOGRAPHY OF AERONAUTICS.
A complete bibliography of aeronautical works issued up to 1909,
published by the Smithsonian Institute, Washington, gives no less than
13,500 entries of book pamphlets, and articles; in all probability,
between that time and the present, the total has been more than
doubled. The following is a list of outstanding work on the subject
from the earliest times, and, in a good many cases, the works
mentioned give further bibliographies. The Smithsonian publication,
differentiating very little between the solid work on the subject
and the magazine article, is of little use except to the advanced
student of the subject; the following list is compiled with a view
to directing attention to the more notable books and publications--a
complete bibliography, as appendix to a work on aeronautics, is an
impossibility:--
_Prodromo All Arte Mæstra_, by Francesco Lana. Brescia, 1670.
_Mathematical Magic_, by J. Wilkins, Bishop of Chester. London, 1691.
_The Air Balloon, or a Treatise on the Aerostatic Globe._ London, 1783.
_Description des Experiences de la Machine Aerostatique_, by F. St
Fond. 2 vols. Paris, 1783.
_Hints of Important Uses to be derived from Aerostatic Globes_, by T.
Martyn. London, 1784.
_Account of the First Aerial Voyage in England_, by V. Lunardi. London,
1784.
_Narrative of M. Blanchard’s Third Aerial Voyage_, translated from the
French of M. Blanchard. London, 1784.
_Journal and Certificates of the Fourth Voyage of M. Blanchard._
London, 1784.
_Breslaw’s Last Legacy._ With an accurate description of the method how
to make the air balloon. London, 1784.
_Thoughts of the Further Improvement of Aerostation._ London, 1785.
_Treatise on Aerostatic Machines_, by J. Southern. Birmingham, 1785.
_Lunardi’s Account of his Second Aerial Voyage from Liverpool, August
9th, 1785._ London, 1785 or 1786.
_An Account of Mr James Decker’s Two Aerial Expeditions._ Norwich, 1785.
_The History and Practice of Aerostation_, by Tiberius Cavallo, F.R.S.
London, 1785.
_Eloge Funebre de M. Pilatre de Rozier_, by M. Lenoir. London, 1785.
_Airopaida_, by T. Baldwin. Chester, 1786.
_An Account of Five Aerial Voyages in Scotland_, by V. Lunardi. London,
1786.
_A Narrative of the Two Aerial Voyages of Dr Jeffries with Mons.
Blanchard_, by Dr Jeffries. London, 1786.
_Account of the Three Last Aerial Voyages made by M. Garnerin._
Somerstown, 1803. (?)
_Aeronautica, or Voyages in the Air_, by M. Garnerin. London, 1803. (?)
_Treatise on the Use of Balloons in Military Operations_, by
Lieut.-Col. Money. London, 1803.
_A Treatise upon the Art of Flying_, by Thomas Walker. Hull, 1810.
_The Aerial Voyage of Mr Sadler across the Irish Channel, October 1st,
1812._ Dublin, 1812.
_A Narrative of the Aerial Voyage of Mr Windham Sadler across the Irish
Channel, July, 1817._ Dublin, 1827.
_The Aeropleustic Art, or Navigation in the Air by Means of Kites or
Buoyant Sails_, by George Pocock. London, 1827.
_Annals of Some Remarkable Aerial and Alpine Voyages_, by T. Forster,
M.B. London, 1832.
_Aeronautica_, by Monk Mason. London, 1838.
_An Essay on Aerial Navigation_, by Joseph MacSweeney, M.D. Cork, 1844.
_The Balloon, or Aerostatic Magazine_, by Henry Coxwell. London, 1845.
_A System of Aeronautics_, by John Wise. Philadelphia, 1850.
_Histoires de la Locomotion Aerienne_, by Julian Turgan. Paris, 1851.
_Balloons for Warfare_, by Henry Coxwell. London, 1854.
_The History of the Charvolant or Kite Carriage._ London, 1851.
_The Giant Balloon_, by F. Silas. London, 1863.
_Meteorological and Physical Observations made in Balloon Ascents_, by
James Glaisher. London, Reprint from Report of British Association,
1864.
_Astra Castra_, by Hatton Turnor. London, 1865.
_The Right to Fly_, translated from the French of Nadar. London, 1866.
_The Mechanical Appliances by which Flight is Attained_, by J. B.
Pettigrew, M.D. London, 1867. (?)
_Travels in the Air_, by James Glaisher. London, 1871.
_Animal Locomotion, with a Dissertation on Aeronautics_, by J. B.
Pettigrew, M.D. London, 1874.
_Animal Mechanism_, by E. J. Marey. London, 1874.
_Aerial Navigation_, by C. B. Mansfield. London, 1877.
_The Aerial World_, by Dr G. Hartig. (New Edition.) London, 1881.
_Ballooning_, by G. May. London, 1886.
_My Life and Balloon Experiences_, by Henry Coxwell. London, 1887.
_My Life and Balloon Experiences_ (second series). London, 1889.
_Experiments in Aerodynamics_, by S. Pierpont Langley. Washington, 1891.
_Aerial Navigation_, by Octave Chanute. New York, 1891.
_Screw-propelled Aeroplane Machines_, by E. J. Stringfellow. Chard,
1892.
_The Internal Work of the Wind_, by S. P. Langley. Washington, 1893.
_Progress in Flying Machines_, by Octave Chanute. New York, 1894.
_Aerial Navigation_, by A. F. Zahm. Philadelphia, 1894.
_Aerial Navigation_, by Fijnje van Salverda. New York, 1894.
_The Aeronautical Annual_, by J. S. Means. 3 vols. Boston, U.S.A.,
1895–6–7.
_Manual of Military Ballooning._ British War Office publication.
London, 1896.
_The Navigation of the Air_, by A. McCallum. Aeronautical Society,
London, 1897.
_Gliding Experiments_, by Octave Chanute. Western Society of Engineers,
U.S.A., 1897.
_Parakites_, by G. T. Woglom. New York, 1897.
_The Mechanism and Equilibrium of Kites_, by Professor Marvin.
Washington, 1897.
_Andree and his Balloon_, by H. Lachambre and A. Machuron. London, 1898.
_La Conquete de l’Air_, by L. Sazerac de Forge. Paris, 1900. This is
one of the most exhaustive accounts of the development of dirigible
airships that has been produced. Special attention is paid to the
Lebaudy type.
_Aerial Navigation_, by Frederick Walker. London, 1902.
_Practical Kites and Aeroplanes_, by Frederick Walker. London, 1903.
_My Airships_, by A. Santos Dumont. London, 1904. A personal account by
the French pioneer of aerostatic experiment.
_Flying Machines with Paddling Wings_, by Andre Delprat. London, 1904.
_Manual of Military Ballooning._ London, by Authority, 1905.
_Resistance of the Air and the Question of Flying_, by Arnold
Samuelson. Hamburg, 1905.
_Navigating the Air._ Published by the Aero Club of America. New York,
1907.
_Flying Machines: Past, Present, and Future_, by A. W. Marshall and H.
Greenly. London, 1907. (?)
_A History of Balloons and Flying Machines_, by Lord Montagu. London,
1907.
_Pocketbook of Aeronautics_, by Major H. Moedebeck. London, 1907. One
of the most valuable reference works on the subject that has been
compiled.
_The Problem of Flight_, by Herbert Chatley. London, 1907.
_Aerial Flight: Aerodynamics_, by F. W. Lanchester. London, 1907.
_Aerial Locomotion_, by A. Graham Bell. Washington, 1907.
_Researches on the Form and Stability of Aeroplanes_, by W. R.
Turnbull. Reprint from the _Physical Review_, London, 1907.
_Aerial Flight: Aerodonetics_, by F. W. Lanchester. London, 1908.
_Airships, Past and Present_, by A. Hildebrandt. London, 1908. An
English translation from the German, which embodies all that had been
done up to 1906 or thereabouts in dirigible construction, with a few
notes on aeroplane design and progress. In various details Hildebrandt
is incorrect, but there is a good deal in his work which is of value to
the student, if a confirming authority can be consulted.
_Aerial Warfare_, by R. P. Hearne. London, 1908.
_Artificial and Natural Flight_, by Sir Hiram Maxim. London, 1908.
Containing an account of all Maxim’s experiments up to the time of
writing.
_The Present Status of Military Aeronautics_, by Major G. O. Squier.
Published by the American Society of Mechanical Engineers. 1908.
_The Problem of Flight_, by Jose Weiss. London, 1908.
_Practical Aerodynamics_, by Major Baden-Powell. (Part 1.) London, 1909.
_The Conquest of the Air_, by A. Berget. London, 1909.
_Vehicles of the Air_, by Victor Lougheed. Chicago and London, 1909.
An illustrated compendium of aeroplane and airship design, sketchily
written, and containing a number of conclusions which at the present
time can hardly be regarded as accurate. Chiefly valuable for diagrams
and data of early machines and engines.
_Model Flying Machines_, by W. G. Aston. London, 1909.
The Aeronautical Classics: 1, _Aerial Navigation_, by Sir George
Cayley; 2. _Aerial Locomotion_, by F. H. Wenham; 3. _The Art of
Flying_, by Thomas Walker; 4. _The Aerial Ship_, by Francesco Lana;
5. _Gliding_, by Percy S. Pilcher, and _The Aeronautical Work of John
Stringfellow_; 6. _The Flight of Birds_, by Giovanni A. Borelli. A
series of small manuals, mainly reprints, edited for the Aeronautical
Society of Great Britain by T. O’Brien Hubbard and J. H. Ledeboer, of
the utmost value to the student of aeronautical history. The rescue of
Walker’s and Borelli’s work from obscurity is in particular noteworthy
as indicative of the valuable work accomplished by the Aeronautical
Society.
_The Boys’ Book of Airships_, by Harry Delacombe, 1910, and _The Boys’
Book of Aeroplanes_, by T. O’Brien Hubbard and C. C. Turner, 1912. Both
these books, published by Grant Richards, are of far greater value than
their titles indicate. Written primarily for boys, they--especially the
latter--contain a mass of historical information, both accurate and
valuable.
_The Langley Memoir on Mechanical Flight_, by S. P. Langley and Charles
Manly. Published by the Smithsonian Institute, Washington.
_Aircraft in Warfare_, by F. W. Lanchester. London, 1913.
_Bird Flight as the Basis of Aviation_, by Otto Lilienthal.
_The Design of Aeroplanes_, by A. W. Judge. London.
_The Mechanics of the Aeroplane_, by Captain Duchesne.
_Airscrews_, by M. A. S. Riach. London. The standard work on the
subject.
_Stability in Aviation_, by G. H. Bryan. London.
_The Properties of Aerofoils_, by A. W. Judge. London.
_Aero Engines_, by G. A. Burls. London.
_High Speed Internal Combustion Engines_, by A. W. Judge. London.
_The Aero Engine_, by S. Kean. London.
_Aircraft_, by Evan J. David. Scribner’s, New York, 1919. A rather
scrappy account of the development of aeroplanes and dirigibles, with
special reference to the war period.
_British Airships: Past, Present, and Future_, by George Whale. London,
1919. A very useful semi-technical handbook of the subject.
_The Aviation Pocket-Book_, by H. Borlase Matthews. An annual
compendium, issued by Messrs Crosby Lockwood & Co., London, giving
fairly full data of technical development year by year. (Not issued
1919 or 1920.)
INDEX
Abaris, legend of, 7.
A.B.C. radial engines, 466–7.
Accidents, committee of inquiry appointed, 299.
Ader, Clement: builds ‘Eole,’ 121;
builds ‘Avion,’ 123;
account of trial flight, 124;
official denial of trial flight, 126;
end of experiments, 127;
compared with the Wrights, 211;
official report on trials, 469.
Advisory Committee, British, 294.
Aerial Experiment Company of America, 179.
_Aerial Locomotion_, by Wenham, 72–76.
_Aerial Navigation_, by Cayley, 45–48.
‘Aerodrome,’ Langley’s, 134–44.
_Aeronautical Classics_, 48.
Aeronautical Exhibitions: The first, Crystal Palace, 69, 82;
the first helicopter at, 71;
Exhibition of 1911, 229;
Paris, 1912, 294;
Paris, 1913, 304;
Olympia, 1913, 300;
Olympia, 1914, 305.
Aeronautical Society, Royal, 72.
Aeronautical Society, Annual Reports, 76.
Ailerons first fitted, 301.
Air Board formed, 258.
Air Force, Royal, formed, 258.
Air Force, Royal, strength of, 258.
Air Mail, Hendon-Windsor, 231.
Air Ministry constituted, 258;
Civil Aviation Department, 264.
Air Navigation Acts, 265.
Airships: Astra Torres, 349–50;
Baby, the, 361;
Barton, 359;
Beta, 361;
Blimp type, 363;
British rigids, 365–70;
Clement-Bayard, 349–50;
Coastal type, 364;
Gamma, 361;
Gross type. 351;
Lebaudy, 348–9, 362;
North Sea type, 364;
Nulli Secundus, 360;
Parseval, 351;
R33 and R34, 368;
R38 class, 374;
R80, 371;
Santos Dumont, 342–47;
Schutte-Lanz, 358;
Willows, 359;
Zeppelin, 341–352–8;
2A, British Army, 361.
Albatross aero engine, 426.
Alcock, Sir John, 266–7.
Allard, attempt at gliding flight, 33.
Allied war air equipment, 251.
Alps, crossed by Chavez, 226.
Aluminium, the Schwartz airship, 340.
Alvaston aero engine, 441.
America, flight across, 231;
R34’s voyage to, 370.
Andes, crossing of the, 269.
Andree’s plans for a dirigible, 331.
Antoinette engine, fitted to Voisin, 181;
fitted to Cody, 192;
fitted to A. V. Roe, 195.
Antoinette monoplane, 290.
Anzani aero engine, 196, 216, 419–21.
Archdeacon, Ernest, 179.
Archytas, legend of, 7.
Area necessary for support, Meerwein’s statement, 42.
Army Air Battalion, British, 238.
_Art of Flying, The_, by Thomas Walker, 48–55.
Ascent, first balloon, 322;
in America, 328;
in England, 323.
Ashmusen aero engine, 444.
Assyrian legends of flight, 5.
Astra Torres airships, 350;
use of ballonets, 330.
Atlantic flight, 265–7.
Audemars, at Bournemouth, 209;
Paris-Berlin flight, 237.
Aulus Gellius, legend of Archytas, 7.
Australian flight, the first, 270.
Aviatik, construction of, 210.
‘Avion’ Ader’s, 123, 211;
official report on, 469.
Ayar Utso, Peruvian legend of, 8.
‘Baby’ airship, the, 361.
Bacon, Francis, on flight, 20.
Bacon, Roger, on flight, 12.
Ballon sondé, the first, 325.
Ballonets, 329–30, 333–4.
Balloon: the Mongolfier type, 318;
first public ascent, 319;
Charles’s hydrogen, 320;
Mongolfierlater types, 320–21–22;
Rozier and d’Arlandes’ ascent, 322;
first ascent in England, 323;
Saussure on cause of lift, 323;
Charles, filling method, 324;
Charles’s and Robert’s ascent, 325;
Blanchard’s channel crossing, 326;
Robert’s observations, 327;
Section, Royal Engineers, 359;
Dirigible (see _dirigibles_), 331–41;
in warfare, 376;
school at Farnborough, 226.
Balloon ascents, proclamation on, 502.
Balloonists: Blanchard, 42, 326, 378;
Mongolfier, 42, 318.
Barton airship, the, 359.
‘Bat,’ the, Pilcher’s glider, 101.
Baumgarten and Wolfert dirigible, 340, 389.
Bayerischer aero engine, 429–30.
Beaumont, circuit of Britain, 220, 230;
wins Paris-Rome race, 230.
‘Beetle’ the, Pilcher’s glider, 103.
Belgian provision of war aircraft, 248.
Benz 4-cylinder aero engine, 401.
Berlin, air services from and to, 268.
Berriman, on helicopter flight, 87.
Besnier’s gliding experiments, 34–5.
‘Beta’ army airship, 361.
B.E.2, the, 297.
B.E.2c, the, 304.
Bibliography, a short, 504.
Biplanes: Albatross, 251;
Avro types, 195;
Bleriot, 183;
Curtiss-Herring, 182;
Cody’s first, 191–2;
Cody’s ‘cathedral,’ 193, 290;
Farman, 181, 217;
Gotha, 252;
Handley-Page, 252;
Moore-Brabazon uses Short, 198;
R.E.1, 305;
R.E.P., 182;
Sikorsky, 249;
Sopwith, 265, 297;
Voisin, 181, 223, 286;
the 1905 Wright, 175.
Black, Dr, 318.
Blackpool flying meeting, 195, 206.
Bladud, legend of, 9.
Blanchard, Jean Pierre, 42, 326, 378.
Bleriot, Louis: 179;
flapping wing experiments, 183;
flights, 184;
at Rheims, 200–204;
a student of Langley, 211;
constructional work, 211–12;
cross-country record, 222;
cross-channel machine, 212, 216, 289;
cross-channel flight, 213–4;
early flights, 221.
Blimp type airship, 363.
Bodensee, German airship, 375.
Boilers, Maxim’s, 386.
Bomb sighting devices, 252.
Bombers: Caudron type, 251;
Gotha, 252;
Handley-Page, 252;
Voisin, 251.
Borelli, compared with da Vinci, 18;
_de Volatu_, 21–26;
his conclusions, 26–27.
Boulogne meeting, the, 178, 206.
Bournemouth meeting, 198, 207–8.
Box Kites, Cody’s, 189.
Brearey’s ‘pectoral cord,’ 83.
Brescia flying meeting, 206.
British flying grounds, the principal, 227;
war construction, 259–60;
war aircraft, 1914, 247;
War Office Trials, 194, 209, 232, 235–7, 296;
War Office requirements, 1913, 300;
war construction, 259–60.
Brooklands in the early days, 197, 228.
Cairo to Cape flight, 270.
Capnobates, legend of, 5.
Capper, Colonel J. E. at Farnborough, 226;
constructs dirigible, 360.
Carra’s dirigible, 332.
Cassiodurus, legends by, 7.
Castel’s helicopter, 87.
Casualties, British war, 234.
Cavallo, Leo, experiments with hydrogen, 318.
Cavendish, discovery of hydrogen, 318.
Cayley, Sir George, 45–48.
Certified pilots, list of in 1911, 228.
Channel crossing by Bleriot, 213–14;
de Lesseps, 215;
C. S. Rolls, 216;
balloon, 326.
Chanute, O., gliding experiments, 107–115;
Wrights’ reference to, 153;
at Wrights’ camp, 157.
Chartres, Duc de, balloon ascent, 329, 333.
Charvolant or kite carriage, Pocock’s, 56.
Chavez, Georges: at Tours, 225;
makes British height record, 225;
crosses the Alps, 226;
fatal accident, 226.
Circuit of Britain race, 220.
Civil Aviation Department, Air Ministry, formed, 264.
Clement-Bayard dirigible, 349–50;
engines, 444.
Clerget rotary engine, 434–6.
Coastal type of British airship, 364.
Coatalen, Louis, 411.
Cockburn, British competitor at Rheims, 201, 206.
Cocking’s parachute, 378.
Cody, S. F., constructs box-kites, 189;
constructs dirigible, 360;
first biplane, 190–1;
first flight in England, 190–1;
first observed flight, 222–3;
various flights, 192;
wins British War Office trials, 235–7;
passenger flights, 193;
‘cathedral’ biplane, 193;
records achieved, 193–4, 223;
at Doncaster, 207;
in circuit of Britain race, 220;
fatal accident, 194.
Colombine, associated with Henson and Stringfellow, 60, 64.
Commercial Zeppelin service, 372.
Construction, British war, 259–60.
Cosmos ‘Jupiter’ engine, 465;
‘Lucifer’ engine, 466.
Cousin, _Histoire de Constantinople_, 11.
Curtiss, Glenn, forms Aerial Experiment Company, 179;
flying boat construction, 242;
flies Langley machine, 243–5;
at Rheims, 201–2.
Curtiss-Herring biplane, 182.
Curtiss Vee-type engine, 416.
Daedalus, legend of, 5.
Daimler aero engines, 389–91, 394–6.
Danti, Giovanni, 12.
D’Arlandes, first balloon ascent, 322.
Darracq aero engines, 440, 442.
De Dion aero engines, 416.
Degen’s flying machine, 52.
De Havilland, height record, 196;
at Farnborough, 228.
Delagrange, at Juvisy meeting, 185–6;
at Rheims, 202;
at Doncaster, 207;
death of, 224;
records made by, 222.
De Lesseps channel crossing, 215.
Demoiselle monoplane, Santos Dumont’s, 184, 285;
Audemars, 209.
Deperdussin monoplane, 294, 301–2.
Derby, aerial, 267.
De Rue, Ferber’s pseudonym, 200.
D’Esterno, gliding machine, 72;
_Du Vol des Oiseaux_, 72.
Dickson, Captain, aero scouting, in 1910, 210;
at Tours meeting, 225.
Dihedral angle, 285.
Diodorus’s story of Abaris, 7.
Dirigibles: French, at Rheims meeting, 203;
Baumgarten and Wolfert, 340;
Carra’s,332;
Dupuy de Lome’s, 336;
de Morveau’s, 332;
Giffard’s, 334–6;
Guyot’s (the first), 332;
Haenlein’s, Paul, 337;
Joseph Mongolfier’s suggestions for propulsion, 331;
Meusnier’s improvements, 333;
Miollan and Janinet, 332;
Renard and Krebs, 338–40;
Schwartz aluminium, 340;
Wellner’s, 331;
(see _airships_ for later types).
Doncaster flying meeting, 1909, 206.
Dorman aero engines, 409–10.
Drexel, Armstrong, world’s height record, 225.
Dugald Clerk’s two-stroke engine, 447.
Dunne monoplane, the, 229;
description of, 293.
Dutheil-Chambers aero engine, 441, 443.
Electric motor airship propulsion, 390–91.
Empedocles, legend of, 6.
Engines: A.B.C. ‘Wasp II.’ radial, 466;
A.B.C. ‘Dragonfly’ radial, 467;
Alvaston rotary, 441;
Antoinette, 181, 241;
Anzani rotary, 196, 216, 419–21;
Albatross radial, 426;
Ashmusan horizontal, 444;
Austro-Daimler vertical, 403;
Bayerischer rotary, 429–30;
Benz 4-cylinder vertical, 259, 401;
Burlat rotary, 439;
Clement-Bayard horizontal, 444;
Clerget rotary, 434–6;
Cosmos ‘Jupiter’ radial, 465;
Cosmos ‘Lucifer’ radial, 466;
Critchley’s list of, 400, 404;
Curtiss Vee type, 416;
Daimler vertical, 389–91, 394–6;
Darracq horizontal, 440, 442;
de Dion Vee type, 416;
Dorman Vee type, 409–10;
Dugald Clerk’s two-stroke, 447;
Dutheil-Chambers horizontal, 441, 443;
Eole, horizontal, 443;
Esnault-Pelterie radial, 422;
Fredericson, horizontal, 457;
Giffard’s, 383;
Gnome rotary, 181, 185, 195, 203, 224, 241,428–9, 431–34;
Gobe and Diard’s two-stroke, 453;
Graham Clark’s list of, 401;
Green vertical, 198, 241, 361, 397–400;
Gyro and Gyro-Duplex rotary, 437–8;
Haenlein’s Lenoir type, 388;
Henson and Stringfellow’s, 383;
Kemp Vee type, 416;
Kolb-Danvin horizontal, 445;
Lamplough two-stroke, 455;
Laviator two-stroke, 454;
Lenoir type, Haenlein’s, 388;
Le Rhone rotary, 436;
Manly, Charles, radial, 139, 396, 417–9;
Maxim’s steam, 384;
Maybach vertical, 261;
Mercedes vertical, 261;
Mercedes-Daimler vertical, 402;
Mercedes 6-cylinder vertical, 459–465;
Mort and New Engine Co. two-stroke, 456;
Napier Vee type, 412, 414–5;
Nieuport Horizontal, 445;
Palons and Beuse horizontal, 445;
Renault Vee type, 243, 415;
Roberts horizontal, 457;
Rolls-Royce Vee type, 266, 412–14;
Salmson rotary, 422–6;
Stringfellow’s, 383;
Sunbeam, 411;
Types of, 393;
Uberursel rotary, 259;
Wolseley Vee type, 405–9;
Wright Brothers, 392–3.
Engine development, 383–468.
‘Eole’ Ader’s monoplane, 121.
Esnault-Pelterie, Robert: early experiments, 179;
R.E.P. biplane, 182;
radial engine, 422.
Exhibitions: first aeronautical, 69, 82;
Paris, 1912, 294;
Paris, 1913, 304;
Olympia, 1913, 298, 299–300;
Olympia, 1914, 305.
Farman’s biplane, Voisin type, 181, 287;
first mile flight in Europe, 182;
first cross-country flight, 222;
flights in 1908–9, 184, 221–2, 223;
four hours’ record, 185;
exhibition flying in England, 186;
at Rheims meeting, 202, 223.
Farnborough, British military establishment at, 226;
de Havilland at, 228.
Felix, Captain, makes 1911 height, record, 230.
Ferber’s, Captain, experiments, 177, 288;
book, _Aviation_, 177;
at Rheims, 200;
death at Boulogne meeting, 178.
Ferguson, H., first flight in Ireland, 223.
First aeronautical exhibition, 69, 82.
Flapping wing or Ornithopter flight: Bleriot’s experiments, 183;
Brearey, F. W., on, 83;
Robert Hooke on, 32–33;
de Villeneuve’s models, 83.
Fokker war aeroplanes, 251;
internal-bracing post-war design, 271.
Forlanini’s helicopter, Professor, 87.
Formation flying, 263.
Fournier at Rheims, 201.
Fourny’s distance record, 1912, 242.
Fredericson two-stroke engine, 457.
French military aero trials, 231–2;
aircraft in 1914, 247;
pioneers, 179.
Galien’s study of properties of air, 317;
proposed airship, 318.
‘Gamma,’ British airship, 361.
German aircraft in 1914, 246;
war aircraft and equipment, 250;
aeroplane, the first, 207;
National Circuit race, 230.
Giffard’s dirigibles, 334–6;
engines, 383.
Gliding flight by Allard, 33;
Besnier 34;
Chanute, 107–115;
Ernest Archdeacon, 179;
Le Bris, 77–82;
Lilienthal, 96–100;
Marshall, Rex, 269;
Montgomery, 115–120;
Pilcher, Percy, 101–106;
Spencer, Charles, 82;
Wright brothers, 145–168.
Gliding patent, d’Esterno’s, 72.
Gobe and Diard rotary engine, 453.
Goldbeater’s skin used by Beaumanoir, 322.
Gordon-Bennett cup, won by Védrines, 294;
race of 1913, 301.
Gotha biplane, 252;
raids on England, 255.
Gnome engine, 181, 185, 203, 241, 428–9, 431–34.
Goupil’s design of monoplane, 91.
Grade, first German monoplane, 207.
Graham-White, London-Manchester flight, 217–220.
Green Engine, vertical, 198, 241, 361, 397–400.
Grimaldi’s claim to flight, 38–39.
Gross airship, 351.
‘Guardian Angel’ parachute, 379.
Guidotti’s experiments, 19.
Guyot’s dirigible, 332.
Guzman, Lorenzo de, 37, 317.
Gyro and Gyro-Duplex rotary engines, 437.
Haenlein, Paul, dirigible construction, 337;
engine used, 388.
Haldane, negotiations with Wrights, 176.
Hamel, Gustav, 231.
Hanouam, Indian legend of, 9.
Handley-Page, F., machines by, 196, 252;
new wing design, 271;
height and load record, 272.
Hargrave, Lawrence, ornithopter experiments, 85.
Havilland, G. de, height record, 196, 240;
at Farnborough, 228.
‘Hawk,’ the, Pilcher’s glider, 104.
Hawker, H. G., height record, 240;
Atlantic attempt, 265.
Helicopters: Castel’s, 87;
da Vinci’s, 19;
Berriman on, 87;
Forlanini’s, 87;
Kimball’s, 88;
Kress’s, 88;
Nadar and de la Landelle’s, 71;
Phillips, W. S., 57;
Principle and disadvantages, 85;
Paucton’s, 39–40.
Henderson, General Sir D., 238–9.
Henson, W. S., and Stringfellow, 57;
Patent specification, 57;
Prospectus of company, 60;
end of experiments, 67.
Henson and Stringfellow’s engines, 383.
Hildebrandt, _Airships Past and Present_, 317.
Hooke, Robert, 21, 32.
Hot air balloons, 318–22.
Hydrogen, discovered by Cavendish, 318;
experiments by Leo Cavallo, 318;
balloon, the Charles, 320.
Icarus, legend of, 5.
Ilmarinen, Finnish legend, 9.
Inca legends, 8.
Independent Force, R.A.F., 262.
Indian legends, 4, 9.
Ireland, first flight in, 223.
Italian aircraft war strength, 248.
Janinet, Miollan and, dirigible, 332.
Jeffries, Dr, balloon voyage across the Channel, 326;
scientific observations on balloon voyage, 328.
‘June Bug’ Curtiss aeroplane, 180.
‘Jupiter’ radial engine, 465.
Jutland, seaplanes at, 254.
Juvisy flying meeting, 186.
Kalevala (Finnish epic), legend from, 9.
Kempt Vee-type aero engine, 416.
Kill Devil camp, the Wrights’, 153, 278.
Kite Balloons: the Parseval-Siegsfeld, 376;
Belgian, 377;
in Naval use, 377.
Kitty Hawk, the Wrights’ camp at, 152–3.
Kœnig, winner of German National Circuit, 1911, 230.
Kolb-Danvin aero engine, 445.
Krebs, Renard and, dirigible, 338–40.
Lambert, Comte de, flies round Eiffel Tower, 185, 207, 223.
Lamplough, two-stroke aero engine, 455.
Lana, Francesco, 21;
biographical details, 27–8;
The Aerial Ship, 28–31.
Lanark, meeting at, 1910, 209.
Lanchester, study of ornithopter flight, 85.
Landelle, de la, helicopter project, 71.
Landemann’s distance record, 1914, 242.
Langley, S. P., _Memoir_, 133;
first experiments, 134;
engines, 135;
model machines, 135;
model flight, 137;
construction of full-sized machine, 138;
official report on trials, 140–4;
Wrights’ reference to, 161;
Bleriot copies design, 183;
machine flown by Glenn Curtiss, 243.
Latham, Hubert, flight of over an hour, 186;
at Rheims, 200, 204, 223;
attempts Channel crossing, 213;
height record, 223;
achieves vertical kilometre, 224.
Laurenzo, Bartolomeo, 317.
Laviator two-stroke engine, 454.
Lebaudy, use of air bags, 334;
airships, 348–9, 362;
engines used, 390.
Le Blon, Hubert, 225.
Le Bris, gliding experiments, 77.
Lefebvre at Rheims, 201, 205.
Legagneaux, height record, 241.
Legends of flight, 3–14.
Lenoir engine used by Haenlein, 386.
Le Rhone rotary aero engine, 436.
Lilienthal, Otto, 95–101;
studied by Voisin, 181;
studied by Wrights, 159;
fatal accident, 100.
London-Manchester flight, 217, 220;
Farman machines used, 182.
London-Paris, first non-stop flight, 230;
regular service, 267.
Looping, 262, 272, 303.
Loraine, Robert, early flights, 210.
‘Lucifer’ radial aero engine, 466.
Lunardi, first balloon ascent in England, 323.
L70 and L71, German dirigibles, 374.
_Mahabarata_, legend from, 4.
Mail services, aerial, 231, 268.
Maitland, Brig.-Gen., parachute descent, 379.
Manly’s radial engine, 139, 396, 417.
Marey, _La Machine Animale_, 22,84, 150.
Martinsyde, Atlantic crossing machine, 266;
monoplane, 291.
Maxim, Sir Hiram, aeroplane, 128;
account of experiments, 129–131;
engines and boilers, 384–8.
‘Mayfly’ airship, 362.
Meerwein’s glider, 41–42;
practical conclusions, 42.
Meetings, flying: Berlin, 209;
Blackpool, 195;
Boulogne, 178, 206;
Bournemouth, 198, 207–8;
Brescia, 206;
Doncaster, 206;
Juvisy, 186;
Lanark, 209;
Rheims, 199–206;
Tours, 225;
decay of, 209.
Mercedes-Daimler vertical engine, 402;
6-cylinder type, 459–465.
Metal aeroplane construction, 311.
Mensier, General, report on Ader’s ‘Avion,’ 469.
Miollan and Janinet dirigible, 332.
Mousnier, General, 333;
death of, 334.
Model machines, Langley’s, 135.
Monge, Marey, experiment with Lana’s ‘aerial ship,’ 32.
Mongolfiers, the, first balloons, 42, 316;
Joseph, later constructions, 320–21;
State pension granted, 321;
on dirigible propulsion, 331.
Monoplanes: Ader’s ‘Avion,’ 123;
Ader’s ‘Eole,’ 122;
Antoinette, 290;
Audemars’s ‘Demoiselle,’ 209;
Bleriot’s, 183;
Bleriot’s cross-channel, 212–6, 289;
Deperdussin, 294, 301–2;
Dunne, 229;
Ferguson’s, 223;
first German, the ‘Grade,’ 207;
Goupil’s, 91;
Handley-Page, 229;
Henson and Stringfellow’s, 57–59;
Martinsyde, 291;
Morane ‘Parasol,’ 302;
Moy’s, 90;
Paulhan-Tatin, 295;
Penaud’s design, 89;
Santos-Dumont’s ‘Demoiselle,’ 184.
Montgomery, gliding experiments, 115–120;
death, 120.
Moore-Brabazon, J. C. T., 197, 223.
Mort, G. F., two-stroke engine, 456.
Moy, Thomas, 90.
Mullar, John, legend of, 8.
Nadar’s Helicopter, 71;
work on Aviation, 71;
balloon experiments, 72.
Napier aero engine, Vee type, 412, 414–15.
Nesteroof, looping, 303.
New Engine Co., two-stroke engine, 456.
Nieuport aero engine, 445.
‘Nulli Secundus’ airship, 360.
N.C.4’s Atlantic crossing, 265.
N.S. type airships, 364.
O’Gorman, Colonel, at Farnborough, 226.
Oliver of Malmesbury, 11.
Ornithopter experiments: Brearey, F. W., 83;
Bleriot, 183;
de Villeneuve, 83–4;
Hooke, 32–3;
Meerwein, 41–2;
studied by Wright, 85.
Palons and Beuse aero engine, 445.
Paprier, London-Paris flight, 230.
Parachutes, da Vinci’s, 19, 378;
Veranzio’s, 19–20;
‘Guardian Angel,’ 379;
modern, 379;
Blanchard’s descents, 378;
Cocking’s descents, 378;
Mongolfier’s descents, 378;
Robertson’s descents, 378;
Maitland’s descents, 378;
rate of fall, 378.
Parseval airship design, 351.
Parseval-Siegsfeld kite balloon, 377.
Patents specification, the Wrights’, 479.
Paucton on Helicopter flight, 39–40.
Paulhan: using Farman biplane, 182;
exhibition flying charges, 186;
at Rheims, 201;
London-Manchester flight, 217–220;
first European height record, 223;
Los Angeles height record, 224.
Pegoud, first to loop the loop, 262, 303.
Penaud, Alphonse, 89;
death of, 90;
reference to, 127.
Perugia, Danti’s experiment at, 12.
Peruvian legends of flight, 8.
Phillips, Horatio, investigations, 91;
flying machine, the, 188–9;
W. H., helicopter, 57.
Pilcher, Percy S., work of, 101–6;
death, 106.
Pilots in 1911, list of certificates, 228.
Plane surfaces, Horatio Phillips’ investigations, 91.
Platz, ascent in Schwartz airship, 340.
Pocock’s kite carriage, 56.
Proclamation on balloon ascents, 502.
Puy de Dome flight, 228.
Pyrenees, first crossed by Tabuteau, 227.
Radial engines, see _engines_.
Reconnaissance, War, 253.
Records, 184–6, 193–196–197–199–201, 221–232, 240–2, 269, 272, 306.
Regiomontanous (John Muller), legend of, 8.
Renard and Krebs’ dirigible, 338–40.
Renault aero engines, 415.
Renaux, Puy de Dome flight, 228;
duration record, 230.
R.E. type, the, 304–5.
R.E.P. biplane, construction of, 182.
Rheims flying week of 1909, 199–206, 225.
Richthofen’s ‘travelling circus,’ 251.
Rigid dirigibles (see _airships_), 365–71.
Robert, discovery of rubber proofing, 319;
observations on balloons, 327.
Roberts two-stroke engine, 457.
Robertson’s parachute descent, 378.
Roe, A. V., constructs first triplane, 192;
summary of construction, 195.
Rogers, C. P., flying across America, 231.
Rolls, C. S., cross-Channel flight, 198, 216, 225;
fatal accident, 198, 208.
Rolls-Royce engines, 266, 412–14.
Rome-Tokio flight, 272.
Ross-Smith’s Australian flight, 270.
Rotary engines (see _engines_).
Rougier, at Juvisy, 186.
Royal Aeronautical Society, 72;
Annual reports, 76.
Royal Aircraft Factory, 236.
Royal Air Force formed, 258;
strength of, 258.
Royal Flying Corps, founding of, 235, 238.
Royal Naval Air Service formed, 238;
in the war period, 255.
Rozier, Pilatre de, 322;
death of, 327.
Rubber proofing, discovery of, 319.
Russian air strength in 1914, 249.
Ryneveld, Cairo to Cape flight, 270.
R34’s voyage to America, 370.
R80, British rigid dirigible, 371.
Salmson radial engine, 422–6.
Santos-Dumont: airship constructions, 342–7;
conclusions regarding dirigibles, 345–7;
first effective aeroplane flight in Europe, 180, 221, 285;
designs ‘14 bis,’ 180, 285;
designs ‘Demoiselle,’ 184;
airship engines, 390.
Saracen of Constantinople, the, 7, 10.
Saussure, observations on hot-air balloons, 323.
Schwartz aluminium dirigible, 340.
Schutte-Lanz airships, 358.
Scouting by aeroplane, 210.
Seaplanes at Jutland, 254;
in 1912–13, 295, 300;
of the period, 254;
submarine war spotting, 254.
Seguin, Laurent, inventor of Gnome engine, 428.
Selfridge, Lieut., killed at Fort Meyer, 199, 222.
Sikorsky biplane, 249.
Simon the Magician, 4, 10.
Somali campaign, aircraft in, 271.
Sopwith, T. O. M., duration record, 196;
distance record, 196;
height record, 197.
Specification of Wright patents, 479.
Spencer, Charles, gliding experiments, 82.
Stability, inherent, 262, 292–3, 304.
Standardising, effects of, 187.
Stream-lining, 293.
Stringfellow, John: prospectus of company, 60;
record of work, 65–70;
engine, 67, 69–70;
engine and models at Crystal Palace, 69;
death of, 70.
Sunbeam aero engine, Vee type, 411.
Swedenborg, theory of flight, 35–6.
Synchronisation of propeller and machine gun, 260.
Tabuteau, Maurice, crosses Pyrenees, 227.
Tarrant triplane, 272.
Taube type of machine, 303.
Thible, Madame, balloon ascent, 323.
Tissandier, _La Navigation Aerienne_, 37;
dirigible construction, 337, 390;
flying at Rheims, 201.
Tokio-Rome flight, 272.
Tours meeting, 225.
Trick flying of the war period, 262.
Triplane, A. V. Roe’s, 192, 195, 291;
the Tarrant, 272.
Two-stroke cycle engines (see _engines_).
Védrines in Circuit of Britain race, 220;
wins Paris-Madrid flight, 230;
speed record at Chicago, 240;
winner of Gordon-Bennett race, 294.
Vertical engines (see _engines_).
Vee type engines (see _engines_).
Veranzio’s parachute, 19–20.
Vickers-Vimy Atlantic aeroplane, 266–7;
Cape-Cairo flight, 270;
airships, 362.
Vinci, Leonardo da, 15;
Treatise on Flight, 16–18;
parachute, 20.
Voisin, gliding experiments, 179;
brothers, biplane construction, 180, 286;
machine used by Moore-Brabazon, 197.
Walker, Thomas, _The Art of Flying_, 48–55.
War Office, British aero trials, 1912, 194, 209, 232, 235–7, 296;
first experiments, 225;
aeroplane purchases, 227;
specifications, 239, 300.
War period, the, 246–263, 306–311.
War, provision of aircraft for, 246–9.
Wellner’s dirigible, 331.
Wenham, _Aerial Locomotion_, 72–6.
Wieland the Smith, legend of, 9.
Wilcox, James, first American balloon ascent, 329.
Willows’s dirigible, 359.
Wolseley Vee-type engine, 405–9.
Wright, Orville, accident at Fort Meyer, 199, 222;
flights by, 199.
Wright brothers, biographical, 145–7;
study of gliding, 147, 277;
experiments begun, 148, 278;
on equilibrium, 149, 278;
on engine power, 162;
on propeller design, 169;
first power-driven flight, 170–1, 221, 282;
description of 1905 machine, 175, 283;
contract with U.S. Government, 174.
Wright, Wilbur, at Le Mans, 199.
Young, Dr, experiments, 43.
Zambeccari, Italian balloonist, 327.
Zeppelin, first investigations, 341;
first constructions, 352;
record of constructions, 352–8;
service commercial, 372.
GLASGOW: W. COLLINS SONS AND CO. LTD.
FOOTNOTES
[1] Aeronautical Classes, No. 5. Royal Aeronautical Society’s
publications.
[2] Aeronautical Classes, No. 5. Royal Aeronautical Society
publications.
[3] This list it as given by Wilbur Wright himself.
[4] _Century Magazine_, September, 1908.
[5] _Aeronautical Journal_, No. 79.
[6] _Aeronautical Journal_, July, 1908.
[7] Smithsonian Publications No. 2329.
[8] Fourth Wilbur Wright Memorial Lecture, _Aeronautical Journal_, Vol.
XX, No. 79, page 75.
[9] _Ibid._ page 73.
[10] _Ibid._ pp. 91 and 102.
[11] _Airships Past and Present._
[12] _Hildebrandt._
[13] _Hildebrandt._
[14] Hildebrandt. _Airships Past and Present._
Transcriber’s Notes
Punctuation and spelling were made consistent when a predominant
preference was found in this book; otherwise they were not changed.
Simple typographical errors were corrected; occasional unbalanced
quotation marks retained. Missing or incorrect accent marks in
non-English words were not changed.
Ambiguous hyphens at the ends of lines were retained; occurrences of
inconsistent hyphenation have not been changed.
Text uses both mid-level decimal points (·) and baseline decimal points
(.) These have not been changed in this eBook.
Index not checked for proper alphabetization or correct page references.
Illustrations have been moved, when necessary, between paragraphs and
outside of quoted material.
Pages with illustrations originally included the phrase, “To face page
nnn”. Such phrases have been deleted in this eBook.
Captions for the three illustrations of ‘The Hawk’, on page 106,
originally were below the last one, but are shown here below each one.
“Parseval-Siegsfeld” and “Parseval-Siegsfield” were printed that way,
but both may be mis-spelled.
Page 160: In the sentence beginning “The travel of the centre of
pressure”, the phrase “in the different tests) = 17 lbs.” was printed
that way, with an unmatched right parenthesis.
Page 485: “on the other wise” was printed that way.
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