AT A MODERN AERODROME
The workshops--Some problems of construction--The
building of a wing--Aeroplane races--The Aerial
Derby--Passenger flights.
The first flying grounds were merely open tracts of land, chosen more or
less haphazard, and offering no more than a smooth landing-point and an
absence of treacherous gusts. But as flying developed, men came together
with their machines, and groups of sheds were built. Then pupils arrived
to learn to fly, and gradually an organisation was evolved. From a
single rough shelter, perched perhaps at the brink of some stretch of
waste land, pilots found themselves promoted to a row of neatly-built
sheds, with a workshop attached to them in which aeroplanes might be
built or repaired. And from this stage, not being contented with what
could be found in the way of natural flying grounds, men uprooted trees,
filled up ditches and hollows, erected fences, barriers, and gates, and
created what we know as the modern aerodrome--a centre, that is to say,
where machines are designed, constructed, and flown, where there are
regular schools for pupils and apprentices, and to and from which the
airmen pass when making cross-country flights. Public interest has also
aided the growth of aerodromes; people are eager to see aeroplanes fly,
and will come in thousands to an air meeting. So, as at the London
Aerodrome, Hendon, there are public enclosures and pavilions, in
addition to the buildings concerned solely with flight; and flying races
and other contests are arranged, in which the pilots at the aerodrome,
as well as those who come from other grounds, meet each other in
friendly rivalry.
To-day, the aerodrome is the rendezvous of those who fly, or build
machines, or seek to learn the art; while the general public, thronging
the stands on racing days, learns more of aviation in an hour than it
would in a month by merely reading of flights that have been made. All
day, from the moment it grows light until the final dusk, there is
activity upon the aerodrome. Machines are brought out and tested; pilots
arrive from other flying grounds; there is a hum of activity in the
workshops; and in regular batches, with this instructor and that, are
pupils taught to handle a craft in flight. It is, to those who have only
a vague knowledge of aviation, a surprise indeed to spend a day at an
aerodrome. They imagine that the industry is no more than haphazard;
that a few machines are built--mostly in small workshops, and that there
is neither method nor organisation in their making. And then, perhaps,
they are taken through a modern factory, and hold such views no more.
By the work of trained men, who have become highly skilled in their art,
are the parts of a flying machine built and assembled; and no sooner is
one machine wheeled from the shops and takes the air, than another is
being made ready. Governments give orders for large batches of craft;
aeroplanes of new types are built and tested. And, in all departments of
the factory, the output of work is constant and well ordered.
First, of course, the machine is designed; and those in the drawing
office are specially trained men. The planning of an aeroplane is a
matter of no simplicity. First of all there is to be considered what may
be termed the main feature of the machine; whether, that is to say, it
is to be built for speed, for weight-lifting, or for aerial touring. For
high-speed flying it will need small sustaining wings; for
weight-lifting, its area must be large; while in aerial touring there is
need for a medium-paced, highly reliable craft, which will ascend
quickly or plane slowly to earth. The characteristic of the machine
determined, there are other problems to be studied--such, for example,
as the placing of the engine and propeller, the position of the body
containing the pilot and passenger, and the arrangement of the control
surfaces. And, above all, the craft must be built strongly. No matter
how well a machine may fly, or how skilled its pilot, there is peril
should its structure have a weakness, or some hidden defect. For months,
perhaps, in the early days of aviation, a faulty machine would fly; and
then some day, subjected to an abnormal strain, a wing or a tail would
break, and the airman would fall to his death. Should an aeroplane dive
suddenly, there may be a tremendous strain upon its planes; and in a
violent wind, while its motor is thrusting it through the gusts, it is
sustaining shocks and jars which may be of tremendous force. It is not,
indeed, the ordinary wear of flying that a designer needs to guard
against, but those excessive strains--caused perhaps by reckless flying,
or the onslaught of a gale--to which a machine may be exposed.
Security lies in one direction only; and that is to give a machine such
a factor of safety as may be equal to all demands--normal or abnormal.
So a designer calculates, before he draws out the plan of a wing, just
what pressure it may have to resist in ordinary flight; and then to this
he adds such strains as might be caused by diving or by violent gusts.
To be completely on the safe side, to be guarded beyond question from
any excessive shock, a modern-type aeroplane will be given a factor of
safety that may be ten or twelve times more than is necessary in the
ordinary passage of the machine through the air; and this security lies
not only in its planes, say, or its controlling gear, but in every wire
and bolt and stay which goes to its construction. And, by this
precaution alone, has one of the gravest risks of aviation been removed.
Formerly, when men built machines, they did so by what is termed
rule-of-thumb; the builder, that is to say, relied upon his own judgment
and experience--small though these were--and submitted his plans to no
rigorous or scientific test. And so lives were lost. But now, even when
he “loops the loop,” or fights a 60-mile-an-hour gale, a pilot has
confidence in the machine he flies. He knows it is strong as a whole;
that it has no hidden weakness or faulty spar; that he may rely upon it
implicitly, even under the acutest strain.
The building of an aeroplane is a problem of great difficulty--such a
problem, in fact, as no other designers of craft, either for land or
sea, are called upon to face. The machine must be immensely strong, and
yet it is essential that it should be light. Its planes cannot bear
through the air more than a certain number of pounds per square foot;
and so if it is to be a practical craft, and raise a useful load, every
pound that can be saved in its construction has a definite value. It is
because such work is so intricate that there is special interest in a
visit to an aeroplane factory. Here, in large, well-lighted workrooms,
are skilled craftsmen employed. Some of the men, now risen to be foremen
of their departments, made their first acquaintance with aviation in the
very early days. Then there were no factories, and an inventor, regarded
invariably as a “crank,” found a mechanic who was intelligent to help
him, and built his craft humbly in some outhouse or shed. Now these
handy mechanics, who perhaps forsook a post in a motor works to join
some scheme to build an aeroplane, find themselves in positions of trust
in a large and flourishing factory--turning out aircraft for Governments
and for private use, and with a staff of workers under their control.
An impression of one of the workrooms in a modern factory may be gained
from a study of the photograph on Plate XIII. This was obtained in the
Grahame-White factory at Hendon. In the foreground of the picture,
resting upon trestles, is one of the sustaining planes of a machine. It
is in its rough stage, prior to being covered with fabric, and the
method of construction may be seen. The system is to use two or more
main-spars, which run the whole length of the wing; and above and below
these pass the thin wooden strips which form a series of ribs. Fig. 90,
representing a monoplane wing in skeleton, should make clear this method
of building. Although such a wing may appear frail, it has in reality a
surprising strength. English ash and silver spruce, in carefully
selected lengths, are the woods used chiefly in aeroplane construction,
and calculations have shown them able to bear a greater strain, weight
for weight, than would a framework made of mild steel. In the future, of
course, when aircraft are built far larger, wood will cease to be
employed--and partly for the reason that, when wing constructions of
great sizes are needed, it will be impossible to obtain timber that can
be cut into spars of a sufficient length and soundness. Then, probably,
will come the day of high-tension steel, and we shall have a liner of
the air built almost after the fashion of a leviathan of the sea; but
for the making of a small machine, at any time, there should be an
advantage in the use of wood.
[Illustration: FIG. 90.--Construction of a Monoplane wing.]
Returning to an inspection of Plate XIII, one may observe, immediately
behind the men who are working upon the wing-frame, two completed floats
for a hydro-aeroplane; while behind these there is a workbench; and in
the far distance, the hull and the centre wing-sections of a craft under
construction. To the right of the centre work-table may be seen a man
seated at a sewing machine; he is busy with the lengths of fabric which
will cover the wooden framework of the wings. Upon the extreme left of
the photograph, partly completed and in the form of a girder
construction of wood, is the body of an aeroplane. Put together
scientifically and from sections of wood specially tested, a remarkable
strength may be obtained by such a method of building. Fig. 91 shows how
a girder aircraft body, supported by trestles only at its ends, may
support from its centre, without yielding, a tray containing a number of
heavy weights.
[Illustration: FIG. 91.--Testing the girder-built body of an aircraft.]
When the wings of a machine are ready and have been sheathed with their
fabric, and when its hull and chassis have been built, it finds its way
into the assembling shop. The motor is bolted in its framework, the
propeller fitted, and the whole construction receives a final overhaul.
And then one morning it is wheeled out upon the aerodrome--its planes
spotless and gleaming in the sun--and is tested for the first time in
flight. In many cases, so great has been the progress in aeroplane
building, that a new machine will do just what its designer intended it
should; there is no longer any doubt as to the craft’s ability to take
the air. But minor adjustments have usually to be made, none the less,
before a machine is delivered to its purchaser; and in the case of a war
machine, bought, say, for the Admiralty or the Army, it needs to
perform--prior to being taken over--a series of special tests. It must
show that it can ascend rapidly and fly at a certain speed, and it must
raise a specified weight of fuel, in addition to that of its pilot and
passenger. The War Office has prepared a list of its requirements for
military machines of different types; and aeroplane builders, if they
plan craft for Government acceptance, must be prepared to submit them to
the trials arranged. A light scouting machine, when it is tested, must
be able to lift its pilot and fuel sufficient for a flight of 300 miles,
and it needs to vary its speed from 30 to 85 miles an hour. Larger
machines, built for scouting, have to carry the weight of a pilot and
observer and 80 lbs. of wireless apparatus; while a craft to be used in
fighting must raise--in addition to its crew--the weight of a gun and
ammunition; this is estimated to represent 300 lbs.
What the maker usually does, when a craft intended for the Government
has been built and given a preliminary testing, is to send it by way of
the air either to Farnborough, where the Royal Aircraft Factory is
situated, or to Eastchurch, in the Isle of Sheppey, where the Royal
Naval Air Service has its headquarters. Then, with the pilot employed by
the firm at its levers, and some military or naval airman as his
passenger, the machine is subjected to its trials; and if it fails, say,
to rise fast enough, or lifts an insufficient weight, it is returned to
its constructor to be adjusted and improved. With sea-planes, naturally,
there are tests upon the water, both as to a craft’s ability to rise and
descend.
Apart from the factory, or factories, upon a modern aerodrome, there are
the offices of the company which controls it; and in addition the sheds
of various firms which, renting accommodation from the owners of the
ground, are operating flying schools or experimenting with new machines.
So that a day spent at an aerodrome, and particularly at such grounds as
Hendon or Brooklands, is never for a moment dull. Even when there is no
air-racing, a fund of interest may be found in the doings at the sheds;
while on those days when a programme of contests is carried out, and
racing craft are “banking” round the pylons, there is so much to be seen
that a spectator becomes almost bewildered. Air-racing, as made popular
by the proprietors of the Hendon aerodrome, forms so fascinating a sight
that, on a day of public holiday, as many as 50,000 people will assemble
in the enclosures.
To stand near one of the pylons--wooden towers which mark the
turning-points of the course--and see the air-racers come rushing by, is
to gain such an impression of speed as almost makes the watcher hold his
breath. The pilot in a flying race has one chief aim: to fly the
shortest way. Every fraction of a second is of importance; and if he can
circle the pylons more skilfully than his rivals, he may win the race,
even though his machine--in its actual speed--may be no faster than
theirs. So a flying race, from the moment the timekeeper waves his flag
and the machines leap from the starting line, is a contest of sheer
nerve and skill. To fly a winning course, upon a high-powered craft,
requires, indeed, a judgment that is exceptional. Towards each of the
mark-towers, hurtling through the air at perhaps 100 miles an hour or
more, comes the airman with a roar and rush. Peering above his screen,
in the fierce wind-blast, he seeks to gauge distance and speed; and
here, if ever there was one, is a crucial test of airmanship. The pilot
knows that, if he would hope to win the race, he must pass as close to
each tower as his skill can take him; and yet, even while he strains to
this end both nerve and eye, he must not forget for an instant what is
the penalty for error. Were he to press too hard upon the rudder-bar,
were the wing-tip to strike the tower instead of sweeping past it, his
machine would swerve sideways with the momentum of its rush, and break
itself to fragments as it crashed upon the ground.
Flying low, and with his motor emitting a deep-throated roar, the airman
comes tearing for a turn. Some distance before reaching the pylon, he
will begin to “bank” his craft; he will, that is to say, incline
downward his inner wing-tip. Were he not to heel his craft it would skid
outwards through its pace, and swing wide at the turn, thus losing a
second or so of time. Down, therefore, he dips this inner wing, until
there may seem no more than a foot or so between it and the ground. The
speed of the machine appears tremendous. It has come up out of the
distance, growing larger moment by moment; and now it seems, as it
rushes towards the pylon, as though it must strike this structure
instead of wheeling past it. Those on the ground, indeed, standing at
the turn, find this illusion strong: it seems to them certain that the
airman will strike the tower. But he, seated midway between the planes,
and with his eye ever watching his inner wing-tip, has a better
view-point and a clearer means of judgment, than the watchers who are
grouped beside the tower. Steeper he banks his planes, until they seem
nearly vertical; and then, with a swift, powerful swing upon his
rudder-bar, he sends his craft round. The inner wing-tip appears almost
to be sweeping the turf at the foot of the tower. And those who may be
standing against it, watching this flashing wing-tip, feel an instinct
to recoil; it seems as though, with its fine-cut edge, it might sweep
among them like a scythe. But in reality there is no risk. The airman,
although he has swung for the turn at lightning speed, has displayed an
accuracy that is perfect. A foot or two of clearance--no more--there may
be between his wing-tip and the tower; but it is enough. In a flash he
has circled and gone, and has whirled away towards another turn--the
roar of his motor dwindling to a heavy drone. And so he flies for lap
after lap, controlling his machine so superbly that it is difficult to
realize that it is a man’s hand, and not some mechanism, that guides the
craft upon its flight. A pylon on the flying track, with a craft
circling it, is seen in Fig. 92, and a photograph of a biplane,
“banking” heavily as it rounds a tower, on Plate XIV.
[Illustration: FIG. 92.--A pylon, or mark-tower, on the flying track.]
Often, after a close-flown race, two perfectly-handled monoplanes will
rush round the last pylon and into the finishing straight, and roar
together past the judge’s box in a flash of planes.
There is an international speed race, for the Gordon-Bennett trophy,
held every year, and to which reference was made in regard to the first
contest in 1909. Then, it may be recalled, the speed of Curtiss the
winner was less than 50 miles an hour. But, mainly by a use of more
powerful engines, the pace of the competing craft has been increased
very largely from year to year, as will be seen from the table below:
+------+----------------+---------+------------------+
| | | H.P. of | Speed |
| Year.| Winner. | Motor. |(Miles per Hour). |
+------+----------------+---------+------------------+
| 1909 | Curtiss | 30 | 48 |
| 1910 | Grahame-White | 100 | 61 |
| 1911 | Weymann | 100 | 78 |
| 1912 | Vedrines | 140 | 105 |
| 1913 | Prevost | 160 | 126 |
+------+----------------+---------+------------------+
With such a growth in speed there has been, naturally, a greater risk
should some mishap occur; and there are two pilots who, meeting with
disaster while flying in this great race, had cause to thank Providence
that they were not killed outright. One is the French champion, Leblanc,
who went to America with a 100-h.p. Bleriot for the contest of 1910.
When flying at high speed, having nearly completed his course, Leblanc’s
motor stopped suddenly, owing to the failure of his petrol. A strong
wind was blowing across the track, and, as he came planing down, the
airman was swept away sideways. Rushing steeply earthward, his craft
only partly in hand, he came into violent collision with a telegraph
pole. The bow of his machine struck the pole, low down near its base;
and so fierce was the impact that the pole was snapped in two, despite
the fact that it was thick round as a man’s body. The front of the
monoplane was crumpled by the shock, and to those who saw the accident,
and heard the crash which accompanied it, there seemed no chance that
the pilot should escape alive. And yet in reality, save for some cuts
and bruises, Leblanc was unhurt. At the moment of the collision he had
been hurled from his seat; shooting out sideways over one wing, he had
missed striking the telegraph pole, and had avoided also any
entanglement with the wreckage of his machine. For some distance he
whirled through the air, so great was the force of the collision; then,
when he did touch ground, it was upon a grassy bank, down which he
rolled without breaking a limb.
The late Gustave Hamel, whose tragic fate has been so heavy a blow to
aviation, lost control of a Bleriot when rounding a pylon in the 1911
race. The machine side-slipped, and struck ground at 90 miles an hour.
So tremendous was the shock that the motor, torn from its supports, went
rolling far away across the ground, and the body of the craft was
reduced to a tangled wreckage. Hamel, like Leblanc, was projected from
his driving seat by the impact. He slid out upon one wing, rolled across
this, and then went sprawling over the turf. Had he not been thrown
clear, had he remained within the hull and been pinned amidst its
fragments, it is almost certain that he would have been killed; but as
it was--striking neither his head nor limbs against any obstruction--he
sustained a slight concussion and nothing more, and was soon flying
again.
An air-race which is more popular than any other, and is seen each year
by millions of spectators, is the Aerial Derby. This was established in
1912, and it was arranged that it should follow within a week after the
great horse-race which takes place on Epsom Downs. For 81 miles, making
a complete circuit of London, ran the course of the first year’s race,
the turning-points being such towers or large buildings as might catch
the airman’s eye. There were seven competitors, six of them with
monoplanes, and the winner was T. O. M. Sopwith, who flew the course in
a 70-h.p. Bleriot in a few minutes less than an hour and a half.
Machines, then, were not so reliable as they are now; nor were pilots so
expert; and there were quaint happenings in this first race. Verrier,
who flew a Maurice-Farman biplane, took up with him a photographer, so
that views might be obtained from the air; but fog was encountered and
heavy cloud-banks, and the airman lost his way. For hours he flew
without any idea where he was going, and once in the distance he caught
sight of the sea. Eventually, just as dusk had begun to fall, he groped
his way back to Hendon--which is the starting and finishing point of
each year’s race. Moorhouse, another of the racers, lost his way also,
wandering away over Sevenoaks; while Valentine, uncertain as to his
direction, landed to make inquiries, and had an amusing experience. A
smooth field presented itself, and towards this he planed, noticing that
a solitary man was standing in it. From him, after he had alighted,
Valentine sought to obtain guidance; but the man, dumbfounded by the
advent of the machine, which had swooped suddenly towards him out of the
empty air, seemed to lose all power of speech. He stood in the field and
merely waved his arms, amazement written upon his face; and, after
trying in vain to make sense of his gestures, Valentine had to fly
farther on and alight again.
In 1913 the course was lengthened to a distance of 94-1/2 miles, and
this time Hamel, who flew at a speed of 76 miles an hour, and proved the
winner, met with a strange mishap while in the air. A brass petrol cap
was, by the vibration of the engine, shaken from the top of a fuel tank
in front of him; and the result was that the spirit bubbled out and blew
back into his face with the rush of wind. He groped, half blinded, for
the cap, which had fallen upon the floor-boards of the machine. But it
was just beyond his reach, and he could not of course relinquish his
hold upon the controlling lever. Prudence suggested a descent, but the
time taken in landing would, he reckoned, cost him his chance of winning
the race. To fly on, however, with the petrol streaming into his eyes,
was impossible; and yet he could not, even by the most strenuous
groping--and with his machine swerving dangerously as he bent within the
hull--recapture this elusive cap. What was to be done? Hamel, after a
moment’s thought, solved the problem neatly. He found that he could just
reach the tank with one hand; whereupon, leaning far forward in his
seat, he slipped a finger into the aperture from which the petrol was
escaping. The position was cramped and awkward, and he could barely use
his controls. But descend he would not; and so he flew for nearly 30
miles, crouching half out of his seat, and with one arm thrust rigidly
forth. His determination was rewarded, for he won the race.
But the pilot of a racing plane is no ordinary man; none, indeed, but
the most expert will dare to handle a high-speed craft. With 160 h.p.
within its frail, light hull, and sustained in flight by the smallest of
wings, the machine must have a master hand upon its levers--a hand light
and yet sure, delicate and yet as strong as steel. Those in France who
fly these racing craft are called the “record” men. Others, who do
trick-flying such as “looping the loop,” are known as the “artists.”
A daily feature of work upon the aerodrome is the giving of passenger
flights. People of all ages, and in all walks of life, are now eager to
fly. Some telephone beforehand, and arrange an aerial journey with a
pilot whose skill they may admire; then they motor to the aerodrome,
find a plane standing ready, and are soon aloft. Others, coming on days
when there is racing, walk to one of the booking-offices in the
enclosures and pay their fee for an immediate flight. At Hendon, for the
convenience of those who want to fly, there is now a scale of regular
charges. A visitor may, by paying two guineas, ascend and circle the
flying ground twice. For a flight outside the limits of the aerodrome,
say in the direction of Edgware, returning towards the Welsh Harp, a fee
of five guineas is charged; while an air journey to Elstree and back,
representing a distance of 16 miles, costs ten guineas. A flight enjoyed
sometimes by passengers who can afford the luxury, is from Hendon to
Brooklands and back; for this, a distance of about 38 miles, the fee is
£26, 5s. Anyone who seeks to hire an aeroplane and its pilot, as he
might a motor-car, for a long cross-country journey by air, will find
the novelty expensive: 20s. a mile is the fee charged, although this is
reduced to 15s. a mile if the return flight is made by the passenger. On
a popular day at the aerodrome, when stands and enclosures are thronged,
flights are booked in great numbers, and several pilots may be busy,
taking one passenger after another.
Building and testing machines, holding air-races, giving passenger
flights; to these is the modern aerodrome devoted. But there is another,
and perhaps an even more important, task, and this is to teach men how
to fly. Schools for tuition are numerous in these days, and special
machines are used and expert instructors employed. The pupils who come
to the flying schools--naval and military officers and civilians from
all walks of life--increase largely in numbers from day to day.