TYPES OF AËROPLANES
France has indeed been the breeding-place for types of aëroplanes.
From France have the nations of late been largely gathering them--save
Germany. She has preferred to evolve her own distinctive types.
Even before Wilbur Wright appeared with his machine at Le Mans and
the details were known, hearsay of his doings had fired the French
imagination to do what he had done. In ignorance of the vital principle
of movable surfaces that the Wrights had evolved, there came into
existence the unbending, rigid type that was not destined to survive.
The first of these was the bird of prey of M. Santos Dumont. Rudely
simple was it in its construction. Two box kites formed the supporting
surface. In the centre was the motor, with the screw behind. To attain
flight the machine was run upon wheels along the ground until a certain
speed was reached, when the machine rose into the air. With this the
inventor did not do much more than make aërial jumps; but rude as it
was it contained one feature which has since been retained in all
aëroplanes. In this one respect it was an advance--and a very necessary
one--upon the Wright machine. That feature was the attachment of
wheels to the machine that has been mentioned above. This was, indeed,
an important step in the evolution of the aërial scout. Had it been
necessary to continue using the external starting catapults that were a
feature of the early experiments of the Wrights, the application of the
aëroplane to warfare would have been somewhat limited.
The well-known Voisin machine was another outcome of this period, but,
imperfect as it was, it brought Mr. Henry Farman into fame, for on it
he was the first man in Europe to fly any distance worthy of mention.
THE FARMAN BIPLANE.
Discontented with the Voisin machine, Mr. Henry Farman constructed one
of his own design. Though it appeared at an early stage of aëroplane
development, it still remains one of the most efficient types of
biplanes. It has been used enormously in France, and armoured Farmans
play an important part in the great war that is proceeding.
Mr. Farman quickly realised that for maintaining lateral stability the
vertical planes fitted between the main planes of the Voisin type were
a very poor substitute for the wing-warping method of the brothers
Wright. He, however, produced the movement of the main surfaces in
an original manner. He hinged small flaps to the rear extremities of
the main planes. These he called “ailerons.” They produce much the
same effect as the wing-warping method of the brothers Wright. When
the biplane tilted sideways, the flaps were drawn down on the side
that was depressed. The pressure of the air on the flaps forced the
aëroplane back on an even keel. In the normal condition the flaps
flew out straight in the wind on a level with the main planes. Another
noticeable feature of Mr. Farman’s machine was the production of the
first light and efficient landing chassis. This was a combination of
wooden skids and bicycle wheels. Below the biplane, on wooden uprights,
he fitted two long wooden skids. On either side of each skid he placed
two little pneumatic tyred bicycle wheels, connected by a short axle.
These were held in position on the skid by stout rubber bands passing
over the axle.
In a general way the wheels raised the skids from the ground, but if
the ascent was abrupt the wheels were forced against the rubber bands
and the skids came in contact with the ground. With the abatement of
the force of the shock the wheels came again into play.
Simplification of the chassis is becoming evident in the latest forms
of all military aëroplanes, the reduction of weight in this portion of
the apparatus being important.
To Mr. Farman belongs the credit of having first applied to his
aëroplane the now famous Gnome motor, in which seven or more cylinders
revolve. It can truly be said that the influence of this motor on
facilitating flight generally, and very particularly military aviation,
has been nothing short of prodigious. The aëroplane, like the airship,
had to wait for the light petroleum motor. Its advent made flight
possible, but achievement in flight would have been comparatively small
had it not been for the welcome appearance of a motor specially adapted
to the purpose.
The early forms of aëroplane engines in which the cylinders were fixed
had proved to be quite unreliable owing to the high speeds at which
the engines had to work. Overheating, loss of power, and stopping
were frequent occurrences. The water-cooling and air-cooling systems
introduced were equally inefficient. The very fact that the cylinders
of the Gnome motor revolved effected the desideratum of automatic
cooling, and also gave a smooth, even thrust to the propeller.
If the aëroplanes in the present war were flying over the enemy’s lines
with old-fashioned engines, they would be dropping down into hostile
hands as quickly as dying flies from the ceiling on the first winter
days.
After the introduction of the Gnome motor, it was quickly realised that
the speeds secured by its use gave the aëroplane a stability that was
absent in the more slowly moving machines. Winds that were the bugbear
of the aëroplanists could then be combated, and the aëroplane ceased
to be the fine-weather machine. Heights could then be climbed that a
little while before were undreamt of. It is said that there are some
disadvantages in the case of revolving cylinders--that they have been
known to produce a gyroscopic effect that has upset the machine. This,
however, is a somewhat doubtful point. It may be urged that the greater
silence of motors with fixed cylinders is an advantage in war. This may
sometimes be so, and it is quite possible that for offensive aëroplanes
a special type of motor may be in the future evolved.
To return to the other features of the Farman machine. The plan he
adopted in his racing machines of making the upper plane larger than
the lower one was a valuable step in speed-producing machines.
The records won by Mr. Farman with his machines alone testify to
its efficiency. Often he has held the world’s records of distance,
duration, and height, wrestling, indeed, for these with the Blériot
monoplane.
In 1911 Mr. Farman began to make types of biplanes specially designed
for military use, and in which he studied how he could best give the
observing officer an unobstructed view of the ground beneath him. He
placed both pilot and observer in seats projecting in front of the main
planes. He also made a new departure in placing his upper plane in
advance of the lower one. He claimed that this facilitates climbing and
descent. He has, however, quite lately evolved a newer type of scouting
machine.
In this the lower plane is only one-third the span of the upper one.
The nacelle is not mounted on the lower plane, as in the ordinary
types of his machine, but, instead, strung from the main spars of the
top one. The usual chassis is absent. There is a single running wheel
mounted at each end of the lower plane, which is brought very close to
the ground. The upper and lower planes are separated by four pairs of
struts. The tail is similar to that used on the ordinary type.
The following are the dimensions of one of the latest 1914 types of
one-seated Farman machines:--
Length 3.75 metres
Span 11.50 metres
Area 26 sq. metres
Weight (total) 290 kgs.
„ (useful) 175 kgs.
Motor 80 h.p. Gnome
Speed 110 km. per hour
The following are the details of one of his high-power hydroplanes
(1914):--
Length 8.80 metres
Span 18.08 metres
Area 50 sq. metres
Weight (total) 605 kgs.
„ (useful) 275 kgs.
Maximum speed 105 km. per hour
[Illustration:
[_Topical Press._
A BLÉRIOT MONOPLANE IN FLIGHT,
showing one of the two wings attached to the tubular body of machine,
chassis, stabilising plane, and rudder at rear.]
THE BLÉRIOT MONOPLANE.
At the same time that Mr. Henry Farman was making his first flights on
his biplanes, M. Blériot was experimenting with monoplanes. His first
attempts were disastrous. Time after time he was dashed to the ground.
But he persevered, and produced a machine which by its performance
staggered the aëronautical world.
When he was first experimenting most people thought that it was
in superposed surfaces that success alone lay. They forgot the
researches of Langley. These had showed that support depended on
two factors--speed and surface; that when speed is increased a less
supporting surface will suffice. The success of Blériot took the world
by surprise. If I were asked to name the men who have done most to
further practical aëronautical development, I should unhesitatingly
say: 1, the brothers Wright; 2, Blériot; 3, Pégoud.
The first have been already dealt with. I will speak of the two latter
together.
Of the work of both there has been one underlying
characteristic--simplicity. The former has produced a machine stripped
indeed of encumbering complexities, in which the restriction of
accessories to what is absolutely necessary is carried to a fine art;
the latter with that very machine has performed experiments in the air
that the most sanguine enthusiast of a few years back would have deemed
far beyond the region of the possible. In his graceful air diving,
looping the loop, and flying upside down, he gave the world a great
object-lesson of the materiality of air. He showed the air can give the
aviator as much support as the water can to a fancy swimmer. He showed
that if the aëroplane is an unstable thing, the human brain can supply
the stability; that in human flight, like the bird and its wings, the
machine and individual can be in closest touch. No one has stripped
the air of its terrors as has M. Pégoud. In the yielding air there is
indeed safety! It is the ground the aviator has to fear!
I have spoken of the simplicity of the Blériot monoplane. In the
machine with which M. Blériot flew over the Channel in 1909, stretched
like the wings of a bird on either side of a tubular wooden frame
partly covered with canvas and tapering to the rear, are placed the two
supporting planes, rounded at the ends. At the front end is placed the
motor (in the original type a three-cylindered engine, now replaced by
the Gnome motor), geared direct to a 6 feet 6 inches wooden propeller,
and on a level with the rear end of the planes. Immediately behind
the engine is the petrol tank, and behind that the aviator’s seat.
Near the rear end of the frame and underneath it is the fixed tail,
with two movable elevating tips. How simple is the working of this
monoplane! Moving a lever backwards and forwards actuates the tips of
the fixed tail at the back of the machine, and causes it to rise or
fall. Moving the same lever from side to side warps the rear surfaces
of the supporting planes. The act of pushing from side to side a bar on
which the aviator’s feet rest puts the rudder into action and steers
the machine.
The triumphs of the Blériot monoplane would fill many pages. It was
the first machine to fly over an expanse of water--the Channel. Later,
it carried M. Prior from London to Paris without a stop, traversing
250 miles in three hours 56 minutes, beating the performances of the
fleetest express trains by three hours. If it no longer for the moment
holds the record of height, which it has so often done, it carried M.
Garros up to a height of 5,000 metres. When his engine broke down at
that prodigious height, by its superb gliding powers it brought him
safely to earth!
It has flown over the Alpine peaks! It carried the first aëroplane
post--1,750 letters and cards--from Hendon to Windsor in seventeen
minutes!
In 1911 Blériot No. XI. flew with ten persons on board.
Its past records have indeed fitted it to be a military machine. It
is doubtlessly destined to play an important rôle in the present war
in the hands of the French aviators. Especially suitable is this type
for the one-seated military machine. Often it may be desirable to
employ a two-seated machine to carry pilot and observer; but there is
often, too, a use for the single-seated type of machine flying at a
rate of some eighty miles an hour. The work of these observers is to
make swift dashes over the enemy’s lines, make a speedy reconnaissance
of the enemy’s position, and return at once to headquarters with what
information has been obtained.
The following are the dimensions, etc., of the 1914 type of armoured
Blériot monoplanes:--
Length 6.15 metres
Span 10.10 metres
Area 19 sq. metres
Motor 80 h.p. Gnome
Speed 100 km. per hour
THE ANTOINETTE MONOPLANE.
There is another monoplane that will figure in the history of
aëronautics--the Antoinette monoplane. This was the first flying
machine to fly in a wind. Up to the time that Mr. Latham went to the
flying meeting at Blackpool, which took place almost immediately after
the famous Rheims meeting, aviators had only dared to fly in calm
weather. On the flying grounds there used to be tiny flags on posts.
When the flags hung down limply that was the time for flying. When they
moved about, even languidly, that was the time to put the aëroplane
to rest in its shed. Aviators then underestimated the capabilities of
their own machines.
When the aviators came to England the island breezes kept the little
flags vigorously moving about. The aviators were consternated. The
public was disappointed. It began to regard flight as a calm-weather
business. Aëroplanes could not face one breath of wind! Of what
practical use would they ever be!
Latham at that time had his Antoinette monoplane at Blackpool. It
consisted of large and strongly built wings, giving a surface of
about 575 square feet, set at a dihedral angle. The motor was some
60 h.p. At the back of the body of the machine were fixed horizontal
and vertical fins. There were hinged horizontal planes at the end of
the tail for elevating or lowering the machine. “Ailerons” were used
on the main surface for controlling lateral stability. One day, at
Blackpool, Latham went up in a very high wind, and remained in the
air for a considerable time. How much of the stability of his machine
was due to his dexterity, or how much to the machine, it is difficult
to say. Probably the fact that the wings were set at a dihedral angle
had much to do with it. He also had a much larger horse power than his
contemporaries, which no doubt contributed to his success. Anyhow, by
the Antoinette monoplane flight was redeemed from the reproach that
it was merely a pastime for ideal weather conditions. From that time
aviators have sought the winds as well as the calms. Now aircraft can
fly in winds of forty-eight or even fifty miles an hour! This step
of Latham gave a great impetus towards the military adoption of the
aëroplane. The military and naval mind tends to despise what is only
of use in the most favourable conditions. It had put aside the airship
till it could combat moderate winds. It did the same with the aëroplane.
The Wright, Farman, and Blériot machines may be described as the
parent types from which have sprung the large variety which at the
present time are at the disposal of the aviator. Amongst the various
types which have sprung from the parent forms we search in vain for
any underlying new principles, if we except the Dunne machine. There
is, however, in the various types plenty of variety of constructional
detail. Perhaps the two most important features of modern aëroplane
work are (1), the gradual substitution of steel in place of wood, and
the general strengthening of aëroplane construction; (2), the armouring
of vital parts of aëroplanes for the exigencies of warfare. Of this
latter innovation mention will be made later. Regarding the various
types of machines now available, it must suffice in this chapter to
especially mention a few which have features of special interest for
the purpose of warlike operations.
The success of the operations of the British aëroplanists in the war
is evidence of the efficiency of the apparatus being used. The British
military aëronautical authorities have evolved a very useful form of
aëroplane. In present circumstances, however, detailed description of
this must be omitted.
WEIGHT-LIFTING MACHINES.
i. _The Cody Biplane._--The Cody type was quite an experimental
machine. It should not, however, be without notice, as it was an early
effort towards the production of weight-lifting machines. These, in
the future, will have to be evolved if the aëroplane is to take a
large part in offensive operations. Scouting and offensive work call
for different types of machines. The Cody biplane had the largest
supporting surface that has been made, excepting that of Sir Hiram
Maxim’s flying machine. The two main surfaces were 52 feet in length,
7 feet 6 inches wide. They had a supporting surface of 775 square
feet. But this was small compared with the Maxim giant, which spread
4,000 square feet of surface. In the Cody machine the front elevators,
which bore some of the load, alone represented 150 square feet. The
two vertical rudders were at equal distances fore and aft of the main
supporting surfaces. A distinctive feature was the elevator. This was
in two separate parts, each of which could be moved independently
of the other. Cody adopted the method of the brothers Wright for
attaining lateral stability and steering--warping the main surfaces.
There were vertical and horizontal rudders operated by a single
steering wheel. Cody used generally an 80 h.p. engine, but in some of
his experiments he went up to 130 h.p. A peculiarity of the screws was
their greater width at the base than at the tips. The weight of the
machine was about one ton. Though it was such a large machine some
attempts were made to give it portability. The two ends of the main
decks, each 16 feet long, were removable. The girder supporting the
elevator could also be detached, as the rear rudder frame was made to
fold back against the body. With this machine Cody flew at excellent
speeds, averaging fifty miles an hour. On one occasion he was credited
with seventy miles an hour.
It was the Cody machine which won the first prizes which were open to
the world at the military trials in 1912. Of all the earlier practical
fliers in this country no one perhaps did so much to popularise flight
as Cody. His pluck and perseverance, despite the constant disasters
that were his lot, gained British appreciation, and all recognised that
if he was not a man of letters he was one of intuition. His well-known
man-lifting kite, unequalled indeed for the purpose for which it was
designed, was an example of the illuminating flashes that were wont to
cross his brain. It was not the product of calculation, but the happy
thought.
ii. _Maurice Farman Biplane._--A type of weight-carrying machine that
has survived is that designed by Mr. Henry Farman’s brother, Mr.
Maurice Farman. This machine has extensions to its main surfaces,
which enable it to carry a considerable weight. It has been found
capable of remaining in the air a very long time, which is an important
consideration for war use, especially when the aëroplane is on the
offensive. It is capable of flying at a very low speed. A disadvantage
is that it requires very skilful piloting, especially when used in high
winds.
THE BREGUET BIPLANE.
Very conspicuous in the Paris Salon exhibitions has been the Breguet
biplane. This is one of very advanced type; it is a military machine
_par excellence_. Simplicity and portability throughout are its
distinguishing features, and these are the essence of a machine
designed for war. One might almost call it a combination of monoplane
and biplane construction. There is the familiar tapering of the
framework, with controlling planes at the end, such as in the Blériot,
but two superposed planes, instead of the bird-like projecting wings
of the Blériot, are above and below the body of the machine. Steel
enters largely into the design. There is a maximum of supporting struts
between the main surfaces. These are constructed with thin metal
ribs, and are therefore flexible, an exceedingly important feature,
rendering the machine exceptionally stable in high and gusty winds.
For portability the main surfaces can be taken out of position in a
few minutes. By the excellent method of hinging the planes to the body
of the machine the former may be turned back and folded up beside the
body of the machine. The aëroplane can therefore be described as a
folding-up one. It can therefore travel on the road like a motor-car,
instead of having to be packed up and conveyed in a wagon. This method
of road conveyance would be impracticable with a machine with its wings
outspread.
THE SHORT DOUBLE-ENGINED AËROPLANE.
How many times have engines failed during flight on both monoplanes
and biplanes! How many tragedies have thus been enacted! Time and
experience indeed have mitigated this type of aërial disaster. The
improvement in engines has been one cause of salvation in this respect,
the practice of vol-planing the other. But even now from the seat of
war comes the news of engines that fail and machines that drop into the
realm of the enemy. The old proverb of having two strings to one’s bow
should apply to aëronautics.
The desideratum, indeed, is the duplication of such a vital part as
the motor. Considerations of weight have been the hindrance to engine
duplication. Mr. Short has given very special attention to this
matter, and has designed what appears to be an excellent machine,
undoubtedly of military value. The biplane is supplied with two Gnome
motors. One drives the screws in the front of the machine, and placed
a considerable distance apart. The other drives a single screw behind
the planes. In the ordinary way both engines run at moderate speed, but
if one fails the acceleration of the speed of the other will keep the
machine flying.
THE VENDÔME MONOPLANE.
A monoplane which has repute in France for strength, general aptitude,
and convenience is the Vendôme type. It has been especially commended
by experts on account of the quickness with which it can be put
together and dismantled. The only criticism to which it has been
exposed is, perhaps, that it is a little too strong for requisite
lightness, and that a modification of the metallic portions might
reduce weight without sacrifice of efficiency. This machine throughout
is made of hickory wood.
BREGUET-BRISTOL BIPLANE.
This is one of the newest machines France has at her disposal. It is a
happy combination of British and French make, due to the collaboration
of two firms, the Bristol Company and La Société Breguet.
The result of the combination is said to be eminently satisfactory. A
distinguishing feature of this machine is rapid dismantlement. There
are two pairs of wings. These are identical, interchangeable, and
connected in each case by a flexible partition, which permits of the
wings being laterally straightened up. The area of this interesting
machine is 39 square metres; length, 8.90 metres; span, 11.50 metres.
THE DESTROYER NIEUPORT MONOPLANE.
During this year, even before the outbreak of war, the aëroplane
had been well armoured and armed. A striking example of an armoured
air-scouting machine is the Nieuport monoplane. This type has obtained
brilliant result. Equipped with pilot, bombs, and armament it has
flown at the rate of 145 kilometres an hour, risen at the rate of 500
metres in 3 minutes 45 seconds, made its departure and landed within an
enclosure of 150 square metres.
This monoplane has 24 square metres of surface, and weighs more than
1,000 kgs. The armoury is carried out by a cuirass of steel or nickel
plates, which cover the vital front parts and the place where the pilot
sits.
ARMOURED CLEMENT-BAYARD MONOPLANE.
This new type is exceedingly well armoured, the protective caps
covering the motor and the middle of the machine.
The following are the dimensions, etc.:--
Length 5.60 metres
Span 9.50 metres
Area 18 sq. metres
Motor 100 h.p. Gnome
Weight 415 kgs.
Speed 150 km. per hour
On June 6th last the French military aviators with their armoured and
armed aëroplanes were reviewed at Villacoublay by General Joffre and
General Bernard, the director of military aëronautics. Amongst the
types of aëroplanes present was the Dorand biplane, having two Gnome
motors driving separate screws, armoured in its vital parts, and
armed with a Hotchkiss mitrailleuse. This was mounted on a pivot,
and could be fired in almost every direction. There were, too, the
Morane-Saulnier, Blériot-Gouin, Nieuport, and Breguet-Bristol types.
M. Raymond, in his speech before the Senate in February last, said
that Germany was in possession of armoured aëroplanes, but that France
had none. The June review at Villacoublay showed what vast strides in
military aëroplane construction the French had made in a few months.
The French military aëroplanes consist of Farman types, and many other
leading French forms. In 1913 there were about 500 French military
aëroplanes and a few naval hydroplanes.
France manufactures a great number of aëroplanes, of late years about
1,000 per year. These include Government machines, those of private
owners and export machines. There are at least twenty-nine French
flying grounds, many of them flying schools and trial grounds of the
leading French airship and aëroplane makers.
In 1913 Italy appears to have had about a hundred military aëroplanes,
including those on order, Blériots, Bristol (monoplanes), Farmans,
Nieuports, and others. She had six or eight naval aëroplanes. She is
well provided with military flying schools and other flying grounds,
nearly all fitted with hangars.
There are military airship hangars at Rome, Milan, Verona, Venice, and
Bracciano.
Belgium has a military school of aviation near Antwerp, and in 1913
she had as many as twenty-four military aëroplanes--H. Farman, 80 h.p.
Gnome. There are in Belgium about half a dozen flying grounds, and as
many aërial societies or clubs.
As already stated, Germany, in the first instance, looked to
Austria-Hungary for her aëroplanes, and the Etrich was an Austrian
machine. In late years, however, Austria’s aëroplanes were mainly
Lohners; the Government favoured this make and discouraged others,
consequently enterprise and invention languished. After the accident to
the Aspern the Lohner was condemned as of too feeble a resistance, and
meanwhile discouragement had effaced all the other systems.
Aëroplanes are used both in the Russian army and navy. Those of the
navy are hydro-aëroplanes, or capable of being so arranged. In number,
the Russian navy has about a dozen. Of military aëroplanes Russia has
probably from 250 to about 300, many of them of modern type, and built
in Russia, the principal types being Rumpler, Albatross, Aviatik,
Nieuport, Farman, Bristol and Deperdussin.
Bulgaria has a number of aëroplanes, mainly Blériots and Bristols.
SYKORSKY’S GIANT AËROPLANE.
A very remarkable type of aëroplane is the giant biplane invented by
the Russian aviator Sykorsky. It doubtless marks the beginning of
a new era in the construction of machines on the heavier-than-air
principle. Most aviators have shirked the use of a machine that could
carry a large number of persons. It would seem that Russia is destined
to take the lead in this class of machine, which may before long put
the lighter-than-air Zeppelins entirely out of date. The machine
of Sykorsky is not, indeed, a mere project, but a reality, for at
Petrograd on February 25th, it flew for eighteen minutes with sixteen
passengers on board. They represented a weight of 1,300 kilogrammes.
The height attained in this flight was 300 metres. On February 27th the
machine flew from Petrograd to Tsarskoe Selo and back again, taking
nine persons, in two hours six minutes, at a height of 1,000 metres.
The performance constituted a triple record of distance, height, and
duration of flight with nine persons on board.
The following are the dimensions, etc.:--
Length 20 metres
Span 37 metres
Surface 182 sq. metres
Distance between planes 2.80 metres
Motive power 4 Argus motors (100 h.p. each)
Weight of motors 220 kgs.
Weight of machine without
passengers 3,500 kgs.
Weight with 16 passengers 4,800 kgs.
The motors are placed in groups of two on each side of the body of the
machine. Each pair works a screw and each individual motor can be put
into action and stopped separately. The body of the machine contains a
chamber for the pilots three square metres in size, a passenger salon
of five square metres, and two other chambers of three and two square
metres respectively. The whole are lit by four windows on each side.
The rooms can be artificially lighted by electricity and warmed by
motor gas. There are, indeed, future possibilities for such a machine
in war!
I have mentioned that the type of aëroplane devised by Lieutenant Dunne
is characterised by a distinctive principle of its own. The claim is
made that it is automatically stable. It has, however, rather a claim
to “inherent stability” than “automatic stability,” if we accept the
terms as Professor Bryan has defined them.
The following details appeared in the “Aëronautical Journal”:--
The salient features of the machine are the backward slope of the
planes, which, in plan view, form an angle with the apex in the
direction of flight, and the absence of a tail or supplementary
planes of any description. The following are its chief
dimensions:--Span, 46 feet; length (fore and aft), from apex to
rear wing tip, 20 feet 4½ inches; length of body, 19 feet; surface,
500 square feet; weight (including pilot and six gallons of
petrol), 1,700 lb.; engine, four-cylinder 50–60 h.p. Green, 1,100
r.p.m., driving twin propellers placed one on either side of the
body in the rear.
The weight in flight being 1,700 lb., the aëroplane carries a load
of about 3 lb. per square foot. The speed in flight averages about
40 m.p.h.
The chord of the surfaces is even throughout--6 feet; the vertical
distance between the surfaces is also constant at 6 feet; at
either extremity a vertical curtain is placed between the surfaces
to prevent leakage of air sideways. The surfaces slope back from
the apex at an angle of 58° on either side, the rear wing tips,
therefore, actually being in the rear of the aft end of the body,
and the entire outer extremities of the wings lying back well
behind the centre of gravity.
The curve or camber of the planes is not uniform, and, briefly,
it may be said that each wing may be viewed as a portion of the
surface of a cone with the apex to the rear. A consequence of this
is that the angle of incidence of each wing gradually decreases
from the root to the tip; so much so, that while the angle at
the root is positive, that at the tip is distinctly negative,
the difference in the respective angles being 45°. Apart from
this, an interesting feature is the extreme downward bend of the
_trailing_ edges over a short distance where the two surfaces
meet in the centre; this arrangement has been adopted chiefly
to enable the aëroplane to right itself naturally in the event
of its having assumed a vertical position in the air. A further
interesting consideration is that this machine is the only one
that could safely be forced backwards. It may be added, briefly,
that the loss in efficiency arising from the negative angle of the
wing-tips is compensated by the backward slope and angle of the
surfaces, which naturally causes the flow of air to be depleted
outwardly beneath the planes, and even induces a certain amount of
compression beneath the outer ends. The body is entirely covered
in; the pilot’s seat is in the prow; the motor further to the rear.
The centre of gravity is well forward, and about six inches above
the lower plane. The propellers are carried on a transverse girder,
and are chain-driven in the same direction--contra-clockwise
viewed from the rear. The centre of the boss is situated 1 foot
2 inches above the lower plane, and 4 feet from the central axis
of the machine. The propellers, designed by Capt. Carden, are
of solid wood, 7 feet in diameter, 7 feet 6 inches pitch, each
weighing 21 lb. The chassis comprises two main wheels, with a small
wheel-and-skid fore and aft. The system of controls is extremely
simple. The trailing edge of each extremity of the upper plane
forms a hinged flap, measuring 7 feet 2 inches by 1 foot 9 inches.
These are independently controlled by two levers, one on either
hand of the pilot a couple of mirrors allow the pilot to ascertain
the working of the steering-flaps when in flight. The throttle
control is fixed to the right-hand lever.
On several occasions, while flying on this machine, the pilot used both
hands for writing and making notes, leaving the machine uncontrolled,
and came down with his hands raised above his head.
Germany has many forms of aëroplanes, and these will be treated of in
the next chapter.
[Illustration: _AVIONS ALLEMANDS_
TIREZ
sur ces Appareils
MONOPLAN TAUBE
TAUBE
MONOPLAN GOTHA
GOTHA
MONOPLAN RUMPLER
RUMPLER
BIPLAN ALBATROS
ALBATROS
ZEPPELIN
A DIAGRAM ISSUED BY THE FRENCH WAR OFFICE FOR THE GUIDANCE OF THE MEN
IN THE TRENCHES.
It gives a silhouette of some Aëroplanes and an Airship in the German
service, and bears the injunction--“German Aëroplanes--fire on these
machines.”]