Aeroplanes and Dirigibles of War

F >> Frederick A. Talbot >> Aeroplanes and Dirigibles of War

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The method of launching the bomb also varies considerably,
experience not having indicated the most efficient method of
consummating this end. In some cases the bombs are carried in a
cradle placed beneath the aeroplane and launched merely by
tilting them in a kind of sling, one by one, to enable them to
drop to the ground, this action being controlled by means of a
lever. In another instance they are dropped over the side of the
car by the pilot, the tail of the bomb being fitted with a swivel
and ring to facilitate the operation. Some of the French
aviators favour a still simpler method. The bomb is attached to
a thread and lowered over the side. At the critical moment it is
released simply by severing the thread. Such aeroplane bombs,
however, constitute a menace to the machine and to the pilot.
Should the bomb be struck by hostile rifle or shell fire while
the machine is aloft, an explosion is probable; while should the
aero plane make an abrupt descent the missiles are likely to be
detonated.

A bomb which circumvents this menace and which in fact will
explode only when it strikes the ground is that devised by Mr.
Marten-Hale. This projectile follows the usual pear-shape, and
has a rotating tail to preserve direction when in flight. The
detonator is held away from the main charge by a collar and
ball-bearing which are held in place by the projecting end of a
screw-releasing spindle. When the bomb is dropped the rotating
tail causes the spindle to screw upwards until the projection
moves away from the steel balls, thereby allowing them to fall
inward when the collar and the detonator are released. In order
to bring about this action the bomb must have a fall of at least
200 feet.

When the bomb strikes the ground the detonator falls down on the
charge, fires the latter, and thus brings about the bursting of
the bomb. The projectile is of the shrapnel type. It weighs 20
pounds complete, is charged with some four pounds of T.N.T., and
carries 340 steel balls, which represent a weight of 5 3/4
pounds.

The firing mechanism is extremely sensitive and the bomb will
burst upon impact with the hull of an airship, water, or soft
soil. This projectile, when discharged, speedily assumes the
vertical position, so that there is every probability that it
will strike the ground fairly and squarely, although at the same
time such an impact is not imperative, because it will explode
even if the angle of incidence be only 5 degrees. It is
remarkably steady in its flight, the balancing and the design of
the tail frustrating completely any tendency to wobble or to turn
turtle while falling.

Other types of missile may be used. For instance, incendiary
bombs have been thrown with success in certain instances. These
bombs are similar in shape to the shrapnel projectile, but are
charged with petrol or some other equally highly inflammable
mixture, and fitted with a detonator. When they strike the
objective the bursting charge breaks up the shell, releasing the
contents, and simultaneously ignites the combustible.

Another shell is the smoke-bomb, which, up to the present, has
been used only upon a restricted scale. This missile is charged
with a certain quantity of explosive to burst the shell, and a
substance which, when ignited, emits copious clouds of dense
smoke. The scope of such a shell is somewhat restricted, it is
used only for the purpose of obstructing hostile artillery fire.
The shells are dropped in front of the artillery position and the
clouds of smoke which are emitted naturally inter fere with the
operations of the gunners. These bombs have also been used with
advantage to denote the position of concealed hostile artillery,
although their utility in this connection is somewhat uncertain,
owing to the difficulty of dropping the bomb so accurately as to
enable the range-finders to pick up the range.

Dropping bombs from aloft appears to be a very simple operation,
but as a matter of fact it is an extremely difficult matter to
strike the target, especially from a high altitude. So far as
the aeroplane is concerned it is somewhat at a disadvantage as
compared with the airship, as the latter is able to hover over a
position, and, if a spring-gun is employed to impart an initial
velocity to the missile, there is a greater probability of the
projectile striking the target provided it has been well-aimed.
But even then other conditions are likely to arise, such as
air-currents, which may swing the missile to one side of the
objective. Consequently adequate allowance has to be made for
windage, which is a very difficult factor to calculate from
aloft.

Bomb-dropping from an aeroplane is even more difficult. If for
instance the aeroplane is speeding along at 60 miles an hour, the
bomb when released will have a speed in the horizontal plane of
60 miles an hour, because momentarily it is travelling at the
speed of the aeroplane. Consequently the shell will describe a
curved trajectory, somewhat similar to that shown in Fig. 7.

On the other hand, if the aeroplane is travelling slowly, say at
20 miles an hour, the curve of the trajectory will be flatter,
and if a head wind be prevailing it may even be swept backwards
somewhat after it has lost its forward momentum, and describe a
trajectory similar to that in Fig. 8.

A bomb released from an altitude of 1000 feet seldom, if ever,
makes a bee-line for the earth, even if dropped from a stationary
airship. Accordingly, the airman has to release the bomb before
he reaches the target below. The determination of the critical
moment for the release is not easy, inasmuch as the airman has to
take into his calculations the speed of his machine, his
altitude, and the direction and velocity of the air-currents.

The difficulty of aiming has been demonstrated upon several
occasions at aviation meetings and other similar gatherings.
Monsieur Michelin, who has done so much for aviation in France,
offered a prize of L1,00--$5,000--in 1912 for bomb-dropping from
an aeroplane. The target was a rectangular space marked out upon
the ground, measuring 170 feet long by 40 feet broad, and the
missiles had to be dropped from a height of 2,400 feet. The
prize was won by the well-known American airman, Lieutenant Riley
E. Scott, formerly of the United States Army. He dropped his
bombs in groups of three. The first round fell clear of the
target, but eight of the remaining missiles fell within the area.

In the German competition which was held at Gotha in September of
the same year the results were somewhat disappointing. Two
targets were provided. The one represented a military bivouac
occupying a superficies of 330 square feet, and the other a
captive balloon resembling a Zeppelin. The prizes offered were
L500, L200, and L80--$2,500, $1,000 and $400--respectively, and
were awarded to those who made the greatest number of hits. The
conditions were by no means so onerous as those imposed in the
Michelin contest, inasmuch as the altitude limit was set at 660
feet, while no machine was to descend within 165 feet. The first
competitor completely failed to hit the balloon. The second
competitor flying at 800 feet landed seven bombs within the
square, but only one other competitor succeeded in placing one
bomb within the space.

Bomb-dropping under the above conditions, however, is vastly
dissimilar from such work under the grim realities of war. The
airman has to act quickly, take his enemy by surprise, avail
himself of any protective covering which may exist, and incur
great risks. The opposing forces are overwhelmingly against him.
The modern rifle, if fired vertically into the air, will hurl the
bullet to a height of about 5,000 feet, while the weapons which
have been designed to combat aircraft have a range of 10,000 feet
or more.

At the latter altitude aggressive tactics are useless. The
airman is unable to obtain a clear sharp view of the country
beneath owing to the interference offered to vision by
atmospheric haze, even in the dearest of weather. In order to
obtain reasonable accuracy of aim the corsair of the sky must fly
at about 400 feet. In this respect, however, the aeroplane is at
a decided advantage, as compared with the dirigible. The machine
offers a considerably smaller target and moves with much greater
speed. Experience of the war has shown that to attempt to hurl
bombs from an extreme height is merely a waste of ammunition.
True, they do a certain amount of damage, but this is due to
luck, not judgment.

For success in aerial bomb operations the human element is mainly
responsible. The daring airman is likely to achieve the greatest
results, as events have proved, especially when his raid is
sudden and takes the enemy by surprise. The raids carried out by
Marix, Collet, Briggs, Babington, Sippe and many others have
established this fact incontrovertibly. In all these operations
the airmen succeeded because of their intrepidity and their
decision to take advantage of cover, otherwise a prevailing mist
or low-lying clouds. Flight-Lieutenant Collet approached the
Zeppelin shed at Dusseldorf at an altitude of 6,000 feet. There
was a bank of mist below, which he encountered at 1,500 feet. He
traversed the depth of this layer and emerged therefrom at a
height of only 400 feet above the ground. His objective was
barely a quarter of a mile ahead. Travelling at high speed he
launched his bombs with what proved to be deadly precision, and
disappeared into cover almost before the enemy had grasped his
intentions. Lieutenant-Commander, now Flight-Commander, Marix
was even more daring. Apparently he had no mist in which to
conceal himself but trusted almost entirely to the speed of his
machine, which probably at times notched 90 miles per hour.
Although his advent was detected and he was greeted with a
spirited fusillade he clung to his determined idea. He headed
straight for the Zeppelin shed, launched two bombs and swung into
the higher reaches of the air without a moment's hesitation. His
aim was deadly, since both bombs found their mark, and the
Zeppelin docked within was blown up. The intrepid airman
experienced several narrow escapes, for his aeroplane was struck
twenty times, and one or two of the control wires were cut by
passing bullets.

The raid carried out by Commanders Briggs and Babington in
company with Lieutenant Sippe upon the Zeppelin workshops at
Friedrichshafen was even more daring. Leaving the Allies' lines
they ascended to an altitude of 4,500 feet, and at this height
held to the pre-arranged course until they encountered a mist,
which while protecting them from the alert eyes of the enemy
below, was responsible for the separation of the raiders, so that
each was forced to act independently and to trust to the compass
to bring him out of the ordeal successfully. Lieutenant Sippe
sighted Lake Constance, and taking advantage of the mist lying
low upon the water, descended to such an extent that he found
himself only a few feet above the roofs of the houses. Swinging
roundto the Lake he descended still lower until at last he was
practically skimming the surface of the Lake, since he flew at
the amazingly low height of barely seven feet off the water.
There is no doubt that the noise of his motor was heard plainly
by the enemy, but the mist completely enveloped him, and owing to
the strange pranks that fog plays with sound deceived his
antagonists.

At last, climbing above the bank of vapour, he found that he had
overshot the mark, so he turned quickly and sped backwards. At
the same time he discovered that he had been preceded by
Commander Briggs, who was bombarding the shed furiously, and who
himself was the object of a concentrated fire. Swooping down
once more, Lieutenant Sippe turned, rained his bombs upon the
objective beneath, drawing fire upon himself, but co-operating
with Commander Babington, who had now reached the scene, he
manoeuvred above the works and continued the bombardment until
their ammunition was expended, when they sped home-wards under
the cover of the mist. Considering the intensity of the hostile
fire, it is surprising that the aeroplanes were not smashed to
fragments. Undoubtedly the high speed of the machines and the
zigzagging courses which were followed nonplussed the enemy.
Commander Briggs was not so fortunate as his colleagues; a bullet
pierced his petrol tank, compelling a hurried descent.

The most amazing feature of these aerial raids has been the
remarkably low height at which the airmen have ventured to fly.
While such a procedure facilitates marksmanship it increases the
hazards. The airmen have to trust implicitly to the fleetness of
their craft and to their own nerve. Bearing in mind the
vulnerability of the average aeroplane, and the general absence
of protective armouring against rifle fire at almost point-blank
range, it shows the important part which the human element is
compelled to play in bomb-dropping operations.

Another missile which has been introduced by the French airmen,
and which is extremely deadly when hurled against dense masses of
men, is the steel arrow, or "flechette" as it is called. It is a
fiendish projectile consisting in reality of a pencil of solid
polished steel, 4 3/4 inches in length. The lower end has a
sharp tapering point, 5/8ths of an inch in length. For a
distance of 1 1/8th of an inch above this point the cylindrical
form of the pencil is preserved, but for the succeeding three
inches to the upper end, the pencil is provided with four equally
spaced angle flanges or vanes. This flanging of the upper end or
tail ensures the arrow spinning rapidly as it falls through the
air, and at the same times preserves its vertical position during
its descent. The weight of the arrow is two-thirds of an ounce.

The method of launching this fearsome projectile is ingenious. A
hundred or even more are packed in a vertical position in a
special receptacle, placed upon the floor of the aeroplane,
preferably near the foot of the pilot or observer. This
receptacle is fitted with a bottom moving in the manner of a
trap-door, and is opened by pressing a lever. The aviator has
merely to depress this pedal with his foot, when the box is
opened and the whole of the contents are released. The fall at
first is somewhat erratic, but this is an advantage, as it
enables the darts to scatter and to cover a wide area. As the
rotary motion of the arrows increases during the fall, the direct
line of flight becomes more pronounced until at last they assume
a vertical direction free from all wobbling, so that when they
alight upon the target they are quite plumb.

When launched from a height they strike the objective with
terrific force, and will readily penetrate a soldier's helmet and
skull. Indeed, when released at a height of 4,000 feet they have
been known to pierce a mounted soldier's head, and pass
vertically through his body and that of his horse also. Time
after time German soldiers have found themselves pinned to the
ground through the arrow striking and penetrating their feet.
Owing to the extremely light weight of the darts they can be
launched in batches of hundreds at a time, and in a promiscuous
manner when the objective is a massed body of infantry or
cavalry, or a transport convoy. They are extremely effective
when thrown among horses even from a comparatively low altitude,
not so much from the fatalities they produce, as from the fact
that they precipitate a stampede among the animals, which is
generally sufficiently serious and frantic to throw cavalry or a
transport-train into wild confusion.

Although aerial craft, when skilfully handled, have proved highly
successful as weapons of offence, the possibilities of such
aggression as yet are scarcely realised; aerial tactics are in
their infancy. Developments are moving rapidly. Great efforts
are being centred upon the evolution of more formidable missiles
to be launched from the clouds. The airman is destined to
inspire far greater awe than at present, to exercise a still more
demoralising influence, and to work infinitely more destruction.

CHAPTER XI
ARMOURED AEROPLANES

The stern test of war has served to reveal conclusively the fact
that aerial craft can be put out of action readily and
effectively, when once the marksman has picked up the range,
whether the gunner be conducting his operations with an anti-
aircraft gun stationed upon the ground, or from a hostile
machine. It will be remembered that Flight-Commander Briggs, on
the occasion of the daring British raid upon the Zeppelin sheds
at Friedrichshafen, was brought to the ground by a bullet which
penetrated his fuel tank. Several other vessels, British,
German, French, and Russian alike, have been thrown out of action
in a similar manner, and invariably the craft which has been
disabled suddenly in this way has fallen precipitately to earth
in the fatal headlong dive.

Previous to the outbreak of hostilities there was considerable
divergence of opinion upon this subject. The general opinion was
that the outspread wings and the stays which constituted the
weakest parts of the structure were most susceptible to gun-fire,
and thus were likely to fail. But practice has proved that it is
the driving mechanism which is the most vulnerable part of the
aeroplane.

This vulnerability of the essential feature of the flying machine
is a decisive weakness, and exposes the aviator to a constant
menace. It may be quite true that less than one bullet in a
thousand may hit the machine, but when the lucky missile does
find its billet its effect is complete. The fact must not be
overlooked that the gunners who work the batteries of
anti-aircraft guns are becommg more and more expert as a result
of practice, so that as time progresses and improved guns for
such duty are rendered available, the work of the aviator is
likely to become more dangerous and difficult. Experience has
proved that the high velocity gun of to-day is able to hurl its
projectile or shell to an extreme height--far greater than was
previously considered possible--so that considerable discretion
has to be exercised by the airman, who literally bears his life
in his hands.

Although elaborate trials were carried out upon the testing
ranges with the weapons devised especially for firing upon flying
machines, captive balloons being employed as targets, the data
thus obtained were neither conclusive nor illuminating. The
actual experiences of airmen have given us some very instructive
facts upon this point for the first time.

It was formerly held that the zone of fire that is to be
considered as a serious danger was within a height of about 4,500
feet. But this estimate was well within the mark. Airmen have
found that the modern projectiles devised for this phase of
operations are able to inflict distinctly serious damage at an
altitude of 9,000 feet. The shell itself may have but little of
its imparted velocity remaining at this altitude, but it must be
remembered that when the missile bursts, the contents thereof are
given an independent velocity, and a wide cone of dispersion,
which is quite sufficient to achieve the desired end, inasmuch as
the mechanism of the modern aeroplane and dirigible is somewhat
delicate.

It was for this reason that the possibility of armouring the
airship was discussed seriously, and many interesting experiments
in this field were carried out. At the same time it was decided
that the armouring should be effected upon lines analogous to
that prevailing in warship engineering. The craft should not
only be provided with defensive but also with aggressive
armament. This decision was not viewed with general approbation.
It was pointed out that questions of weight would arise,
especially in relation to the speed of the machine. Increased
weight, unless it were accompanied by a proportionate
augmentation of power in the motor, would react against the
efficiency and utility of the machine, would appreciably reduce
its speed, and would affect its climbing powers very adversely.
In some quarters it was maintained that as a result the machine
would even prove unsuited to military operations, inasmuch as
high speed is the primary factor in these.

Consequently it was decided by the foremost aviating experts that
machines would have to be classified and allotted to particular
spheres of work, just as warships are built in accordance with
the special duty which they are expected to perform. In
reconnaissance, speed is imperative, because such work in the air
coincides with that of the torpedo-boat or scout upon the seas.
It is designed to acquire information respecting the movements of
the enemy, so as to assist the heavier arms in the plan of
campaign. On the other hand, the fighting corsair of the skies
might be likened to the cruiser or battleship. It need not
possess such a high turn of speed, but must be equipped with
hard-hitting powers and be protected against attacking fire.

One attempt to secure the adequate protection against gun-fire
from the ground assumed the installation of bullet-proof steel
plating, about one fifth of an inch thick, below the tank and the
motor respectively. The disposition of the plating was such as
to offer the minimum of resistance to the air and yet to present
a plane surface to the ground below. So far as it went this
protection was completely effective, but it failed to armour the
vital parts against lateral, cross and downward fire while aloft.
As the latter is more to be feared than the fire from the ground,
seeing that it may be directed at point blank range, this was a
decided defect and the armour was subsequently abandoned as
useless.

The only effective method of achieving the desired end is to
armour the whole of the carriage or fuselage of the adroplane,
and this was the principle adopted by the Vickers Company. The
Vickers military aeroplane is essentially a military machine. It
is built of steel throughout. The skeleton of the machine is
formed of an alloy which combines the qualities of aluminium and
steel to ensure toughness, strength, and lightness. In fact,
metal is employed liberally throughout, except in connection with
the wings, which follow the usual lines of construction. The
body of the car is sheathed with steel plating which is bullet
proof against rifle or even shrapnel fire. The car is designed
to carry two persons; the seats are therefore disposed
tandemwise, with the observer or gunner occupying the front seat.

The defensive armament is adequate for ordinary purposes. Being
fitted with a 100 horse-power motor, fairly high speeds are
attainable, although the velocity is not equal to that of
machines constructed upon conventional lines, inasmuch as there
is an appreciable increase in weight.

The car is short and designed upon excellent stream lines, so
that the minimum of resistance to the air is offered, while at
the same time the balancing is perfect. The sides of the car are
brought up high enough to protect the aviators, only their heads
being visible when they are seated. The prow of the car follows
the lines generally adopted in high speed torpedo boat design;
there is a sharp knife edge stem with an enclosed fo'c's'le, the
latter housing the gun.

Another craft, designed for scouting operations, may be likened
to the mosquito craft of the seas. This machine, while a biplane
like the military aeroplane, is of lighter construction,
everything being sacrificed to speed in this instance. It is
fitted with a 100 horse-power motor and is designed to carry an
observer if required. There is no offensive armament, however.
The fuel tank capacity, moreover, is limited, being only
sufficient for a two or three hours' flight. While this is
adequate for general reconnoitring, which for the most part
entails short high speed flights, there are occasions when the
Staff demands more prolonged observations conducted over a
greater radius. This requisition can be met by eliminating the
observer, whose duties in this instance must be assumed by the
pilot, and substituting in place of the former, a second fuel
tank of sufficient capacity for a flight of four or five hours,
thereby bringing the term of action in the air to about 6 1/4
hours. This machine travels at a very high speed and is
eminently adapted to its specific duty, but it is of limited
service for general purposes.

The arming of an aeroplane, to enable it to defend itself against
hostile attack or to participate in raiding operations upon the
aerial fleet of the enemy, appears to be a simple task, but as a
matter of fact it is an undertaking beset with difficulties
innumerable. This is especially the case where the aeroplane is
of the tractive type, that is to say where the propellers are
placed in the forefront of the machine and in their revolution
serve to draw the machine forward. All other considerations must
necessarily be sacrificed to the mounting of the propeller.
Consequently it is by no means easy to allot a position for the
installation of a gun, or if such should be found there is grave
risk of the angle of fire being severely restricted. In fact, in
many instances the mounting of a gun is out of the question: it
becomes a greater menace to the machine than to the enemy.

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