The Mastery of the Air

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Sir Hiram's first machine, which was made in 1890, was designed
to be guided by a double set of rails, one set arranged below and
the other above its running wheels. The intention was to make
the machine raise itself just off the ground rails, but yet be
prevented from soaring by the set of guard rails above the
wheels, which acted as a check on it. The motive force was given
by a very powerful steam-engine of over 300 horse-power, and
this drove two enormous propellers, some 17 feet in length. The
total weight of the machine was 8000 pounds, but even with this
enormous weight the engine was capable of raising the machine
from the ground.

For three or four years Sir Hiram made numerous experiments with
his aeroplane, but in 1894 it broke through the upper guard rail
and turned itself over among the surrounding trees, wrecking
itself badly.

But though the Maxim aeroplane did not yield very practical
results, it proved that if a lighter but more powerful engine
could be made, the chief difficulty iii the way of aerial flight
would be removed. This was soon forthcoming in the invention of
the petrol motor. In a lecture to the Scottish Aeronautical
Society, delivered in Glasgow in November, 1913, Sir Hiram
claimed to be the inventor of the first machine which actually
rose from the earth. Before the distinguished inventor spoke of
his own work in aviation he recalled experiments made by his
father in 1856-7, when Sir Hiram was sixteen years of age. The
flying machine designed by the elder Maxim consisted of a small
platform, which it was proposed to lift directly into the air by
the action of two screw-propellers revolving in reverse
directions. For a motor the inventor intended to employ some
kind of explosive material, gunpowder preferred, but the lecturer
distinctly remembered that his father said that if an apparatus
could be successfully navigated through the air it would be of
such inevitable value as a military engine that no matter how
much it might cost to run it would be used by Governments.

Of his own claim as an inventor of air-craft it would be well to
quote Sir Hiram's actual words, as given by the Glasgow Herald,
which contained a full report of the lecture.

"Some forty years ago, when I commenced to think of the subject,
my first idea was to lift my machint by vertical propellers, and
I actually commenced drawings and made calculations for a machine
on that plan, using an oil motor, or something like a Brayton
engine, for motive power. However, I was completely unable to
work out any system which would not be too heavy to lift itself
directly into the air, and it was only when I commenced to study
the aeroplane system that it became apparent to me that it would
be possible to make a machine light enough and powerful enough to
raise itself without the agency of a balloon. From the first I
was convinced that it would be quite out of the question to
employ a balloon in any form. At that time the light high-speed
petrol motor had no existence. The only power available being
steam-engines, I made all my calculations with a view of using
steam as the motive power. While I was studying the question of
the possibility of making a flying machine that would actually
fly, I became convinced that there was but one system to work on,
and that was the aeroplane system. I made many calculations, and
found that an aeroplane machine driven by a steam-engine ought to
lift itself into the air."

Sir Hiram then went on to say that it was the work of making an
automatic gun which was the direct cause of his experiments with
flying machines. To continue the report:

"One day I was approached by three gentle- men who were
interested in the gun, and they asked me if it would be possible
for me to build a flying machine, how long it would take, and how
much it would cost. My reply was that it would take five years
and would cost L50,000. The first three years would be devoted
to developing a light internal-combustion engine, and the
remaining two years to making a flying machine.

"Later on a considerable sum of money was placed at my disposal,
and the experiments commenced, but unfortunately the gun business
called for my attention abroad, and during the first two years of
the experimental work I was out of England eighteen months.

"Although I had thought much of the internal-combustion engine it
seemed to me that it would take too long to develop one and that
it would be a hopeless task in my absence from England; so I
decided that in my first experiments at least I would use a
steam-engine. I therefore designed and made a steam-engine and
boiler of which Mr. Charles Parsons has since said that, next to
the Maxim gun, it developed more energy for its weight than any
other heat engine ever made. That was true at the time, but is
very wide of the mark now."

Speaking of motors, the veteran lecturer remarked: "Perhaps
there was no problem in the world on which mathematicians had
differed so widely as on the problem of flight. Twenty years ago
experimenters said: 'Give us a motor that will develop 1
horse-power with the weight of a barnyard fowl, and we will very
soon fly.' At the present moment they had motors which would
develop over 2 horse-power and did not weigh more than a 12-pound
barnyard fowl. These engines had been developed--I might say
created--by the builders of motor cars. Extreme lightness had
been gradually obtained by those making racing cars, and that had
been intensified by aviators. In many cases a speed of 80 or 100
miles per hour had been attained, and machines had remained in
the air for hours and had flown long distances. In some cases
nearly a ton had been carried for a short distance."

Such words as these, coming from the lips of a great inventor,
give us a deep insight into the working of the inventor's mind,
and, incidentally, show us some of the difficulties which beset
all pioneers in their tasks. The science of aviation is, indeed,
greatly indebted to these early inventors, not the least of whom
is the gallant Sir Hiram Maxim.

CHAPTER XIX
The Wright Brothers and their Secret Experiments

In the beginning of the twentieth century many of the leading
European newspapers contained brief reports of aerial experiments
which were being carried out at Dayton, in the State of Ohio,
America. So wonderful were the results of these experiments, and
so mysterious were the movements of the two brothers--Orville and
Wilbur Wright--who conducted them, that many Europeans would not
believe the reports.

No inventors have gone about their work more carefully,
methodically, and secretly than did these two Americans, who,
hidden from prying eyes, "far from the madding crowd", obtained
results which brought them undying fame in the world of aviation.

For years they worked at their self-imposed task of constructing
a flying machine which would really soar among the clouds. They
had read brief accounts of the experiments carried out by Otto
Lilienthal, and in many ways the ground had been well paved for
them. It was their great ambition to become real "human birds";
"birds" that would not only glide along down the hillside, but
would fly free and unfettered, choosing their aerial paths of
travel and their places of destination.

Though there are few reliable accounts of their work in those
remote American haunts, during the first six years of the present
century, the main facts of their life-history are now well known,
and we are able to trace their experiments, step by step, from
the time when they constructed their first simple aeroplane down
to the appearance of the marvellous biplane which has made them
world-famed.

For some time the Wrights experimented with a glider, with which
they accomplished even more wonderful results than those obtained
by Lilienthal. These two young American engineers--bicyclemakers
by trade--were never in a hurry. Step by step they made
progress, first with kites, then with small gliders, and
ultimately with a large one. The latter was launched into the
air by men running forward with it until sufficient momentum had
been gained for the craft to go forward on its own account.

The first aeroplane made by the two brothers was a very simple
one, as was the method adopted to balance the craft. There were
two main planes made of long spreads of canvas arranged one above
another, and on the lower plane the pilot lay. A little plane in
front of the man was known as the ELEVATOR, and it could be moved
up and down by the pilot; when the elevator was tilted up, the
aeroplane ascended, when lowered, the machine descended.

At the back was a rudder, also under control of the pilot. The
pilot's feet, in a modern aeroplane, rest upon a bar working on a
central swivel, and this moves the rudder. To turn to the left,
the left foot is moved forward; to turn to the right the right
foot.

But it was in the balancing control of their machine that the
Wrights showed such great ingenuity. Running from the edges of
the lower plane were some wires which met at a point where the
pilot could control them. The edges of the plane were flexible;
that is, they could be bent slightly either up or down, and this
movement of the flexible plane is known as WING WARPING.

You know that when a cyclist is going round a curve his machine
leans inwards. Perhaps some of you have seen motor races, such
as those held at Brooklands; if so, you must have noticed that
the track is banked very steeply at the corners, and when the
motorist is going round these corners at, say, 80 miles an hour,
his motor makes a considerable angle with the level ground, and
looks as if it must topple over. The aeroplane acts in a similar
manner, and, unless some means are taken to prevent it, it will
turn over.

Let us now see how the pilot worked the "Wright" glider. Suppose
the machine tilted down on one side, while in the air, the pilot
would pull down, or warp, the edges of the planes on that side of
the machine which was the lower. By an ingenious contrivance,
when one side was warped down, the other was warped up, with the
effect that the machine would be brought back into a horizontal
position. (As we shall return to the subject of wing warping in a
later chapter, we need not discuss it further here.)

It must not be imagined that as soon as the Wrights had
constructed a glider fitted with this clever system of
controlling mechanism they could fly when and where they liked.
They had to practise for two or three years before they were
satisfied with the results of their experiments: neglecting no
detail, profiting by their failures, and moving logically from
step to step. They never attempted an experiment rashly: there
was always a reason for what they did. In fact, their success
was due to systematic progress, achieved by wonderful
perseverance.

But now, for a short time, we must leave the pioneer work of the
Wright brothers, and turn to the invention of the petrol engine
as applied to the motor car, an invention which was destined to
have far-reaching results on the science of aviation.

CHAPTER XX
The Internal-combustion Engine

We have several times remarked upon the great handicap placed
upon the pioneers of aviation by the absence of a light but
powerful motor engine. The invention of the internal-combustion
engine may be said to have revolutionized the science of flying;
had it appeared a century ago, there is no reason to doubt that
Sir George Cayley would have produced an aeroplane giving as good
results as the machines which have appeared during the last five
or six years.

The motor engine and the aeroplane are inseparably connected; one
is as necessary to the other as clay is to the potter's wheel, or
coal to the blast-furnace. This being the case, it is well that
we trace briefly the development of the engine during the last
quarter of a century.

The original mechanical genius of the motoring industry was
Gottlieb Daimler, the founder of the immense Daimler Motor Works
of Coventry. Perhaps nothing in the world of industry has made
more rapid strides during the last twenty years than
automobilism. In 1900 our road traction was carried on by means
of horses; now, especially in the large cities, it is already
more than half mechanical, and at the present rate of progress it
bids fair to be soon entirely horseless.

About the year 1885 Daimler was experimenting with models of a
small motor engine, and the following year he fitted one of his
most successful models to a light wagonette. The results were so
satisfactory, that in 1888 he took out a patent for an internal-
combustion engine--as the motor engine is technically called--and
the principle on which this engine was worked aroused great
enthusiasm on the Continent.

Soon a young French engineer, named Levassor, began to experiment
with models of motor engines, and in 1889 he obtained, with
others, the Daimler rights to construct similar engines in
France. From now on, French engineers began to give serious
attention to the new engine, and soon great improvements were
made in it. All this time Britain held aloof from the motor-car;
indeed, many Britons scoffed at the idea of
mechanically-propelled vehicles, saying that the time and money
required for their development would be wasted.

During the years 1888-1900 strange reports of smooth-moving,
horseless cars, frequently appearing in public in France, began
to reach Britain, and people wondered if the French had stolen a
march on us, and if there were anything in the new invention
after all. Our engineers had just begun to grasp the immense
possibilities of Daimler's engine, but the Government gave them
no encouragement.

At length the Hon. Evelyn Ellis, one of the first British
motorists, introduced the "horseless carriage" into this country,
and the following account of his early trips, which appeared
in the Windsor and Eton Express of 27th July, 1895, may be
interesting.

"If anyone cares to run over to Datchet, they will see the Hon.
Evelyn Ellis, of Rosenau, careering round the roads, up hill and
down dale, and without danger to life or limb, in his new motor
carriage, which he brought over a short time ago from Paris.

"In appearance it is not unlike a four-wheeled dog-cart, except
that the front part has a hood for use on long "driving" tours,
in the event of wet weather; it will accommodate four persons,
one of whom, on the seat behind, would, of course, be the
'groom', a misnomer, perhaps, for carriage attendant. Under the
front seat are receptacles, one for tools with which to repair
damages, in the event of a breakdown on the road, and the other
for a store of oil, petroleum, or naphtha in cans, from which to
replenish the oil tank of the carriage on the journey, if it be a
long one.

"Can it be easily driven? We cannot say that such a vehicle
would be suitable for a lady, unless rubber-tyred wheels and
other improvements are made to the carriage, for a grim grip of
the steering handle and a keen eye are necessary for its safe
guidance, more especially if the high road be rough. It never
requires to be fed, and as it is, moreover, unsusceptible of
fatigue, it is obviously the sort of vehicle that should soon
achieve a widespread popularity in this country.

"It is a splendid hill climber, and, in fact, such a hill as that
of Priest Hill (a pretty good test of its capabilities) shows
that it climbs at a faster pace than a pedestrian can walk.

"A trip from Rosenau to Old Windsor, to the entrance of Beaumont
College, up Priest Hill, descending the steep, rough, and
treacherous hill on the opposite side by Woodside Farm, past the
workhouse, through old Windsor, and back to Rosenau within an
hour, amply demonstrated how perfectly under control this
carriage is, while the sensation of being whirled rapidly along
is decidedly pleasing."

Another pioneer of motorism was the Hon. C. S. Rolls, whose
untimely death at Bournemouth in 1910, while taking part in the
Bournemouth aviation meeting, was deeply deplored all over the
country. Mr. Rolls made a tour of the country in a motor-car in
1895, with the double object of impressing people with the
stupidity of the law with regard to locomotion, and of
illustrating the practical possibilities of the motor. You may
know that Mr. Rolls was the first man to fly across the Channel,
and back again to Dover, without once alighting.

CHAPTER XXI
The Internal-combustion Engine(Cont.)

I suppose many of my readers are quite familiar with the working
of a steam-engine. Probably you have owned models of
steam-engines right from your earliest youth, and there are few
boys who do not know how the railway engine works.

But though you may be quite familiar with the mechanism of this
engine, it does not follow that you know how the petrol engine
works, for the two are highly dissimilar. It is well, therefore,
that we include a short description of the internal-combustion
engine such as is applied to motor-cars, for then we shall be
able to understand the principles of the aeroplane engine.

At present petrol is the chief fuel used for the motor engine.
Numerous experiments have been tried with other fuels, such as
benzine, but petrol yields the best results.

Petrol is distilled from oil which comes from wells bored deep
down in the ground in Pennsylvania, in the south of Russia, in
Burma, and elsewhere. Also it is distilled in Scotland from
oil shale, from which paraffin oil and wax and similar substances
are produced. When the oil is brought to the surface it contains
many impurities, and in its native form is unsuitable for motor
engines. The crude oil is composed of a number of different
kinds of oil; some being light and clear, others heavy and thick.

To purify the oil it is placed in a large metal vessel or
"still". Steam is first passed over the oil in the still, and
this changes the lightest of the oils into vapours. These
vapours are sent through a series of pipes surrounded with cold
water, where they are cooled and become liquid again. Petrol is
a mixture of these lighter products of the oil.

If petrol be placed in the air it readily turns into a vapour,
and this vapour is extremely inflammable. For this reason petrol
is always kept in sealed tins, and very large quantities are not
allowed to be stored near large towns. The greatest care has to
be exercised in the use of this "unsafe" spirit. For example, it
is most dangerous to smoke when filling a tank with petrol, or to
use the spirit near a naked light. Many motor-cars have been set
on fire through the petrol leaking out of the tank in which it is
carried.

The tank which contains the petrol is placed under one of the
seats of the motor-car, or at the rear; if in use on a
motor-cycle it is arranged along the top bar of the frame, just
in front of the driver. This tank is connected to the
"carburettor", a little vessel having a small nozzle projecting
upwards in its centre. The petrol trickles from the tank into
the carburettor, and is kept at a constant level by means of a
float which acts in a very similar way to the ballcock of a water
cistern.

The carburettor is connected to the cylinder of the engine by
another pipe, and there is valve which is opened by the engine
itself and is closed by a spring. By an ingenious contrivance
the valve is opened when the piston moves out of the cylinder,
and a vacuum is created behind it and in the carburettor. This
carries a fine spray of petrol to be sucked up through the
nozzle. Air is also sucked into the carburettor, and the mixture
of air and petrol spray produces an inflammable vapour which is
drawn straight into the cylinder of the engine.

As soon as the piston moves back, the inlet valve is
automatically closed and the vapour is compressed into the top of
the cylinder. This is exploded by an electric spatk, which is
passed between two points inside the cylinder, and the force of
the explosion drives the piston outwards again. On its return
the "exhaust" or burnt gases are driven out through another
valve, known as the "exhaust" valve.

Whether the engine has two, four, or six cylinders, the car is
propelled in a similar way for all the pistons assist in turning
one shaft, called the engine shaft, which runs along the centre
of the car to the back axle.

The rapid explosions in the cylinder produce great heat, and the
cylinders are kept cool by circulating water round them. When
the water has become very hot it passes through a number of
pipes, called the "radiator", placed in front of the car; the
cold air rushing between the coils cools the water, so that it
can be used over and over again.

No water is needed for the engine of a motor cycle. You will
notice that the cylinders are enclosed by wide rings of metal,
and these rings are quite sufficient to radiate the heat as
quickly as it is generated.

CHAPTER XXII
The Aeroplane Engine

We have seen that a very important part of the
internal-combustion engine, as used on the motor-car, is the
radiator, which prevents the engine from becoming overheated and
thus ceasing to work. The higher the speed at which the engine
runs the hotter does it become, and the greater the necessity for
an efficient cooling apparatus.

But the motor on an aeroplane has to do much harder work than the
motor used for driving the motor-car, while it maintains a much
higher speed. Thus there is an even greater tendency for it to
become overheated; and the great problem which inventors of
aeroplane engines have had to face is the construction of a light
but powerful engine equipped with some apparatus for keeping it
cool.

Many different forms of aeroplane engines have been invented
during the last few years. Some inventors preferred the radiator
system of cooling the engine, but the tank containing the water,
and the radiator itself, added considerably to the weight of the
motor, and this, of course, was a serious drawback to its
employment.

But in 1909 there appeared a most ingeniously-constructed engine
which was destined to take a very prominent part in the progress
of aviation. This was the famous "Gnome" engine, by means of
which races almost innumerable have been won, and amazing records
established.

We have already referred to the engine shaft of the motor-car,
which is revolved by the pistons of the various fixed cylinders.
In all aeroplane engines which had appeared before the Gnome the
same principle of construction had been adopted; that is to say,
the cylinders were fixed, and the engine shaft revolved.

But in the Gnome engine the reverse order of things takes place;
the shaft is fixed, and the cylinders fly round it at a
tremendous speed. Thus the rapid whirl in the air keeps the
engine cool, and cumbersome tanks and unwieldy radiators can be
dispensed with. This arrangement enabled the engine to be made
very light and yet be of greater horse-power than that attained
by previously-existing engines.

A further very important characteristic of the rotary-cylinder
engine is that no flywheel is used; in a stationary engine it has
been found necessary to have a fly-wheel in addition to the
propeller. The rotary-cylinder engine acts as its own fly-wheel,
thus again saving considerable weight.

The new engine astonished experts when they first examined it,
and all sorts of disasters to it were predicted. It was of such
revolutionary design that wiseacres shook their heads and said
that any pilot who used it would be constantly in trouble with
it. But during the last few years it has passed from one triumph
to another, commencing with a long-distance record established by
Henri Farman at Rheims, in 1909. It has since been used with
success by aviators all the world over. That in the Aerial Derby
of 1913--which was flown over a course Of 94 miles around
London--six of the eleven machines which took part in the race
were fitted with Gnome engines, and victory was achieved by Mr.
Gustav Hamel, who drove an 80-horse-power Gnome, is conclusive
evidence of the high value of this engine in aviation.

CHAPTER XXIII
A Famous British Inventor of Aviation Engines

In the general design and beauty of workmanship involved in the
construction of aeroplanes, Britain is now quite the equal of her
foreign rivals; even in engines we are making extremely rapid
progress, and the well-known Green Engine Company, profiting by
the result of nine years' experience, are able to turn out
aeroplane engines as reliable, efficient, and as light in pounds
weight per horse-power as any aero engine in existence.

In the early days of aviation larger and better engines of
British make specially suited for aeroplanes were our most urgent
need.

The story of the invention of the "Green" engine is a record of
triumph over great difficulties.

Early in 1909--the memorable year when M. Bleriot was firing the
enthusiasm of most engineers by his cross-Channel flight; when
records were being established at Rheims; and when M. Paulhan won
the great prize of L10,000 for the London to Manchester flight--
Mr. Green conceived a number of ingenious ideas for an aero
engine.

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