Aeroplanes and Dirigibles of War

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

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Although the Zeppelin was accepted as a perfect machine it has
never been possible to disperse the atmosphere of disaster with
which it has been enveloped from the first. Vessel after vessel
has gone up in smoke and flame: few craft of this type have
enjoyed more than an evanescent existence; and each successive
catastrophe has proved more terrible than its predecessor. But
the Teutonic nation has been induced to pin its whole faith on
this airship, notwithstanding that the more levelheaded engineers
of other countries have always maintained the craft to be a
"mechanical monstrosity" condemned from its design and principles
of construction to disaster. Unshaken by this adverse criticism,
Germany rests assured that by means of its Zeppelins it will
achieve that universal supremacy which it is convinced is its
Destiny.

This blind child-like faith has been responsible for the
establishment and development of the Zeppelin factories. At
Friedrichshafen the facilities are adequate to produce two of
these vessels per month, while another factory of a similar
capacity has been established at Berlin. Unfortunately such big
craft demand large docks to accommodate them, and in turn a large
structure of this character constitutes an easy mark for hostile
attack, as the raiding airmen of the Allies have proved very
convincingly.

But the Zeppelin must not be under-rated. Magnificent
performances have been recorded by these vessels, such as the
round 1,000 miles' trip in 1909, and several other equally
brilliant feats since that date. It is quite true that each
astounding achievement has been attended by an equally stupendous
accident, but that is accepted as a mere incidental detail by the
faithful Teutonic nation. Many vivid prophecies of the
forthcoming flights by Zeppelin have been uttered, and it is
quite probable that more than one will be fulfilled, but success
will be attributable rather to accident than design.

Although the Zeppelin is the main stake of the German people in
matters pertaining to aerial conquest, other types of airships
have not been ignored, as related in another chapter. They have
been fostered upon a smaller but equally effective scale. The
semi-rigid Parseval and Gross craft have met with whole-hearted
support, since they have established their value as vessels of
the air, which is tantamount to the acceptance of their military
value.

The Parseval is pronounced by experts to be the finest expression
of aeronautical engineering so far as Teuton effort is concerned.
Certainly it has placed many notable flights to its credit. The
Gross airship is an equally serviceable craft, its lines of
design and construction closely following those of the early
French supple airships. There are several other craft which have
become more or less recognised by the German nation as
substantial units of war, such as the Ruthemberg,
Siemens-Schukert, and so forth, all of which have proved their
serviceability more or less conclusively. But in the somewhat
constricted Teuton mind the Zeppelin and the Zeppelin only
represents the ultima Thule of aerial navigation and the means
for asserting the universal character of Pan-Germanism as well as
"Kultur."

CHAPTER IV
AIRSHIPS OF WAR

So much has been said and written concerning the Zeppelin
airship, particularly in its military aspect, that all other
developments in this field have sunk into insignificance so far
as the general public is concerned. The Zeppelin dirigible has
come to be generally regarded as the one and only form of
practical lighter-than-air type of aircraft. Moreover, the name
has been driven home with such effect that it is regarded as the
generic term for all German airships.

These are grievous fallacies. The Zeppelin is merely one of a
variety of types, even in Germany, although at the moment it
probably ranks as the solitary survivor of the rigid system of
construction. At one time, owing to the earnestness with which
the advantages of this form of design were discussed, and in view
of the fact that the Zeppelin certainly appeared to triumph when
all other designs failed, Great Britain was tempted to embrace
the rigid form of construction. The building of an immense
vessel of this class was actively supported and it was aptly
christened the "May-fly." Opponents of the movement tempered
their emphatic condemnatory criticism so far as to remark that it
MAY FLY, but as events proved it never did. The colossal craft
broke its back before it ever ventured into the air, and this
solitary experience proving so disastrous, the rigid form of
construction was abandoned once and for all. The venture was not
in vain; it brought home to the British authorities more
convincingly than anything else that the Zeppelin was a
mechanical monstrosity. The French never even contemplated the
construction of such a craft at that time, estimating it at its
true value, and the British failure certainly served to support
French antagonism to the idea. Subsequently, however, an attempt
at rigid construction was made in France with the "Spiess"
airship, mainly as a concession to public clamour.

Even in Germany itself the defects of the Zeppelin were
recognised and a decided effort to eliminate them was made by
Professor Schutte in co-operation with a manufacturer of
Mannheim named Lanz. The joint product of their ambitions, the
Schutte-Lanz, is declared to be superior to the Zeppelin, but so
far it has failed to justify any of the claims of its designers.
This vessel, which also favours the colossal, is likewise of the
rigid type, but realising the inherent dangers accruing from the
employment of metal for the framework, its constructors have used
wood, reinforced and strengthened where necessary by metallic
angle-iron, plates, and bracing; this utilisation of metal is,
however, carried out very sparingly. The first vessel of this
class was a huge failure, while subsequent craft have not proved
much more successful.

In fact, one of the largest German airships ever designed, L4,
is, or rather was, a Schutte-Lanz, with a capacity of 918,000
cubic feet, but over 6,000 pounds lighter than a Zeppelin of
almost similar dimensions. I say "was" since L4 is no more. The
pride of its creators evinced a stronger preference for Davy
Jones' Locker than its designed realm. Yet several craft of this
type have been built and have been mistaken for Zeppelins owing
to the similarity of the broad principles of design and their
huge dimensions. In one vital respect they are decidedly
inferior to their contemporary--they are not so speedy.

The most successful of the German lighter-than-air machines are
those known respectively as the semi rigid and non-rigid types,
the best examples of which are the Gross and Parseval craft.
Virtually they are Teutonic editions of the successful French
craft of identical design by which they were anticipated. The
Lebaudy is possibly the most famous of the French efforts in this
direction. The gas-bag has an asymmetrical shape, and is pointed
at both ends, although the prow is blunter or rounder than the
stem. The gas-bag comprises a single chamber for the inflating
agent, the distended shape of the envelope being sustained by
means of an air-ballonet. By varying the contents of the latter
through the agency of a pump the tension of the gas in the
lifting envelope can be maintained, and the shape of the inflated
balloon preserved under all conditions.

Beneath the gas-bag is a long strengthened girder, and from this
in turn the car is suspended. It is the introduction of this
rigid girder which is responsible for the descriptive generic
term of "semi-rigid." On the other hand the "non-rigid" type may
be roughly described as a pisciform balloon fitted with
propelling machinery, inasmuch as the car containing the driving
machinery is suspended from the balloon in the manner of the car
in the ordinary drifting vessel. So far as the French effort is
concerned the Bayard-Clement type is the best example of the
non-rigid system; it is represented in Germany by the Parseval
class.

The Gross airship has been definitely adopted as a military
machine by the German authorities, and figures in the "M" class.
The "M-IV" completed in 1913 is the largest of this type, and
differs from its prototypes in that it carries two cars, each
fitted with motors, whereas the earlier machines were equipped
with a single gondola after the French pattern. This vessel
measures 320 feet in length, has a maximum diameter of 44 1/2
feet, displaces 13 tons, and is fitted with motors developing 450
horse-power, which is sufficient to give it a speed of 47 miles
per hour. This vessel represents a huge advance upon its
predecessors of this design, inasmuch as thelatter were about 245
feet in length by 36 1/4 feet in diameter, and displaced only six
tons, while the single car was provided with a motor developing
only 150 horse-power, the speed being 28 miles per hour. Thus it
will be seen that a huge development has suddenly taken place, a
result due no doubt to the co-operation of the well-known
engineer Basenach. The "M-IV" is essentially an experiment and
great secrecy has been maintained in regard to the trials which
have been carried out therewith, the authorities merely
vouchsafing the fact that the airship has proved completely
successful in every respect; conclusive testimony of this is
offered by the inclusion of the vessel in the active aerial fleet
of Germany.

But it is the Parseval which is regarded as the finest type of
airship flying the German flag. This vessel is the product of
slow evolution, for it is admitted to be a power-driven balloon.
Even the broad lines of the latter are preserved, the shape being
that of a cylinder with rounded ends. It is the direct outcome
of the "Drachen-Balloon," perfected by Parseval and Siegsfeld,
the captive balloon which is an indispensable part of the German
military equipment.

The complete success of the suspension system in this captive
balloon prompted Parseval to continue his researches and
experiments in regard to the application of power to the vessel,
so as to induce it to move independently of the wind. The
suspension system and the car are the outstanding features of the
craft. It is non-rigid in the strictest interpretation of the
term, although, owing to the incorporation of the steadying
hollow "mattress" (as it is called by its inventor), the strength
of the suspension system, and the substantial character of the
car, it conveys an impression of great solidity. The thinnest
rope, both manilla and steel, in the suspension system is as
thick as a man's finger, while the car, measuring 30 feet in
length by 6 feet in width, carried out in wood, is a striking
example of the maximum of strength with the minimum of weight,
being as steady and as solid as a boat's deck. The propellers
are collapsible, although in the latest craft of this class they
are semi-rigid.

The mechanical equipment is also interesting. There are two
propellers, and two motors, each nominally driving one propeller.
But should one motor break down, or motives of economy, such as
husbanding of fuel, render it advisable to run upon one engine,
then the two propellers may be driven by either of the motors.

The inventor has perfected an ingenious, simple, and highly
efficient coupling device to attain this end, but to ensure that
the propeller output is of the maximum efficiency in relation to
the engine, the pitch of the propellers may be altered and even
reversed while the engine is running. When one motor only is
being used, the pitch is lowered until the propellers revolve at
the speed which they would attain if both engines were in
operation. This adjustment of the propeller pitch to the most
economical engine revolutions is a distinctive characteristic,
and contributes to the efficiency and reliability of the Parseval
dirigible to a very pronounced degree.

Steering in the vertical plane is also carried out upon
distinctive lines. There are no planes for vertical steering,
but movement is accomplished by tilting the craft and thus
driving the gas from one end of the balloon to the other. This
is effected by the manipulation of the air-ballonets, one of
which is placed at the prow and stem of the gas bag respectively.
If it is desired to descend the gas is driven from the forward to
the after end of the envelope, merely by inflating the bow
ballonet with air by means of a pump placed in the car. If
ascent is required, the after-ballonet is inflated, thereby
driving the gas to the forward end of the balloon, the buoyancy
of which is thus increased. The outstanding feature of the
"Drachen-Balloon" is incorporated in the airship. This is the
automatic operation of the safety valve on the gas-bag directly
by the air ballonets. If these ballonets empty owing to the
pressure of the gas within the envelope, a rope system disposed
within the balloon and connecting the ballonets and the gas-valve
at the top is stretched taut, thereby opening the gas-valve. In
this manner the gas-pressure becomes reduced until the ballonets
are enabled to exercise their intended function. This is a
safety precaution of inestimable value.

The Parseval is probably the easiest dirigible to handle,
inasmuch as it involves no more skill or knowledge than that
required for an ordinary free balloon. Its movements in the
vertical plane are not dissimilar to those of the aeroplane,
inasmuch as ascent and descent are normally conducted in a
"screwing" manner, the only exception being of course in abrupt
descent caused by the ripping of the emergency-valve. On one
occasion, it is stated, one of the latest machines of this type,
when conducting experimental flights, absolutely refused to
descend, producing infinite amusement both among the crowd and
those on board.

The development of the Parseval is directly attributable to the
influence and intimate interest of the Kaiser, and undoubtedly
this represents the wisest step he ever made in the realm of
aeronautics. It certainly has enabled the German military
machine to become possessed of a significant fleet of what may be
described as a really efficient and reliable type of dirigible.
The exact number of military Parsevals in commission is unknown,
but there are several classes thereof, in the nature of aerial
cruisers and vedettes.

The largest and most powerful class are those known as the B
type, measuring about 240 feet in length by 40 feet maximum
diameter, of 223,000 cubic feet capacity, and fitted with two
motorsand two propellers. This vessel carries about 10
passengers, can climb to a maximum height of approximately 8,500
feet, and is capable of remaining in the air for twenty hours
upon a single fuel charge. While this is the largest and most
serviceable type of Parseval designed for military duties, there
is another, the A class, 200 feet in length with accommodation
for six passengers in addition to the crew of three, which is
capable of attaining a maximum altitude of 6,700 feet, and has an
endurance capacity of 15 hours. This class also is fitted with
twin propellers and motors. In addition there are the C and
E classes, carrying from four to eight passengers, while the
vedettes are represented by the D and F classes, which have a
maximum altitude of 2,000 feet and can remain aloft for only five
hours upon a single fuel charge. These smaller vessels, however,
have the advantage of requiring only one or two men to handle
them. The present military Parseval dirigible is made in one of
these five standardised classes, experience having established
their efficiency for the specified military services for which
they are built. In point of speed they compare favourably with
the latest types of Zeppelin, the speeds of the larger types
ranging from 32 to 48 miles per hour with a motor effort of 360
to 400 horse-power.

So far as the French airships of war are concerned, the fleet is
somewhat heterogeneous, although the non-rigid type prevails.
The French aerial navy is represented by the Bayard-Clement,
Astra, Zodiac, and the Government-built machines. Although the
rigid type never has met with favour in France, there is yet a
solitary example of this system of construction--the Spiess,
which is 460 feet in length by 47 feet in diameter and has a
displacement of 20 tons. The semi-rigid craft are represented
by the Lebaudy type, the largest of which measures 293 feet in
length by 51 feet in diameter, and has a displacement of 10 tons.

One may feel disposed to wonder why the French should be
apparently backward in this form of aerial craft, but this may be
explained by the fact that the era of experiment had not been
concluded at the time war was declared, with the result that it
has been somewhat difficult to determine which type would meet
the military requirements of the country to the best advantage.
Moreover, the French military authorities evinced a certain
disposition to relegate the dirigible to a minor position,
convinced that it had been superseded by the heavierthan-air
machine. Taken on the whole, the French airship fleet is
inferior to the German in point of speed, if not numerically, but
this deficiency is more than counterbalanced by the skill and
ability of the men manning their craft, who certainly are
superior to their contemporaries in Germany, combined with the
proved character of such craft as are in service.

The same criticism may be said to apply to Great Britain. That
country was backward in matters pertaining to the airship,
because its experiments were carried out spasmodically while
dependence was reposed somewhat too much upon foreign effort.
The British airships are small and of low speed comparatively
speaking. Here again it was the advance of the aeroplane which
was responsible for the manifestation of a somewhat indifferent
if not lethargic feeling towards the airship. Undoubtedly the
experiments carried out in Great Britain were somewhat
disappointing. The one and only attempt to out-Zeppelin the
Zeppelin resulted in disaster to the craft before she took to the
air, while the smaller craft carried out upon far less ambitious
lines were not inspiritingly successful. Latterly the non-rigid
system has been embraced exclusively, the craft being virtually
mechanically driven balloons. They have proved efficient and
reliable so far as they go, but it is the personal element in
this instance also which has contributed so materially to any
successes achieved with them.

But although Great Britain and France apparently lagged behind
the Germans, appreciable enterprise was manifested in another
direction. The airship was not absolutely abandoned: vigilance
was maintained for a superior type of craft. It was an instance
of weighing the advantages against the disadvantages of the
existing types and then evolving for a design which should
possess the former without any of the latter. This end appears
to be achieved with the Astra type of dirigible, the story of the
development of which offers an interesting chapter in the annals
of aeronautics.

In all lighter-than-air machines the resistance to the air
offered by the suspension ropes is considerable, and the
reduction of this resistance has proved one of the most
perplexing problems in the evolution of the dirigible. The air
is broken up in such a manner by the ropes that it is converted
into a brake or drag with the inevitable result that the speed
undergoes a severe diminution. A full-rigged airship such as the
Parseval, for instance, may present a picturesque appearance, but
it is severely unscientific, inasmuch as if it were possible to
eliminateor to reduce the air-resistance offered by the ropes,
the speed efficiency might be raised by some sixty per cent and
that without any augmentation of the propelling effort. As a
matter of fact Zeppelin solved this vexatious problem
unconsciously. In his monster craft the resistance to the air is
reduced to a remarkable degree, which explains why these vessels,
despite all their other defects are able to show such a turn of
speed.

It was this feature of the Zeppelin which induced Great Britain
to build the May-fly and which likewise induced the French
Government to stimulate dirigible design and construction among
native manufacturers, at the same time, however, insisting that
such craft should be equal at least in speed to the Zeppelins.
The response to this invitation was the Spiess, which with its
speed of 45 miles per hour ranked, until 1914, as one of the
fastest dirigibles in the French service.

In the meantime a Spanish engineer, Senor Torres, had been
quietly working out a new idea. He realised the shortcomings of
the prevailing types of airships some eleven years ago, and
unostentatiously and painstakingly set out to eliminate them by
the perfection of a new type of craft. He perfected his idea,
which was certainly novel, and then sought the assistance of the
Spanish Government. But his fatherland was not adapted to the
prosecution of the project. He strove to induce the authorities
to permit even a small vessel to be built, but in vain. He then
approached the French Astra Company. His ambition was to build a
vessel as large as the current Zeppelin, merely to emphasise the
value of his improvement upon a sufficiently large scale, and to
enable comparative data concerning the two designs to be
obtained. But the bogey of expense at first proved insuperable.
However, the French company, decided to give the invention a
trial, and to this end a small "vedette" of about 53,000 cubic
feet displacement was built.

Although an unpretentious little vessel, it certainly served to
emphasise the importance of the Torres idea. It was pitted
against the "Colonel Renard," the finest ship at that time in the
French aerial service, which had proved the fastest airship in
commission, and which also was a product of the Astra Company.
But this fine craft was completely outclassed by the puny
Astra-Torres.

The builders and the inventor were now additionally anxious
to illustrate more emphatically the features of this design and
to build a far larger vessel. The opportunity was offered by the
British Government, which had been following the experiments with
the small Astra-Torres in France. An order was given for a
vessel of 282,500 cubic feet displacement; in this instance it
was ranged against another formidable rival--the Parseval. But
the latter also failed to hold its own against the Spanish
invention, inasmuch as the Astra-Torres built for the British
authorities exceeded a speed of 50 miles per hour in the official
tests. This vessel is still doing valuable duty, being attached
to the British air-service in France.

The achievements of the British vessel were not lost upon the
French Government, which forthwith placed an order for a huge
vessel of 812,200 cubic feet capacity, equipped with motors
developing 1,000 horse-power, which it was confidently expected
would enable a speed of 60 miles per hour to be attained. Thus
France would be able to meet the Germans upon fairly level terms,
inasmuch as the speed of the latest Zeppelins does not exceed 60
miles per hour. So confident were the authorities that a second
order for an even larger vessel was placed before the first large
craft was completed.

This latter vessel is larger than any Zeppelin yet built, seeing
that it displaces 38 tons, and is fitted with motors developing
1,000 horse-power. It has recently been completed, and although
the results of the trials, as well as the dimensions of the craft
have not been published, it is well known that the speed has
exceeded 60 miles per hour, so that France now possesses the
speediest dirigible in the world.

The Torres invention has been described as wonderful,
scientifically perfect and extremely simple. The vessel belongs
to the non-rigid class, but the whole of the suspension system is
placed within the gas-bag, so that the air-resistance offered by
ropes is virtually eliminated in its entirety, for the simple
reason that practically no ropes are placed outside the envelope.
The general principle of design may be gathered from the
accompanying diagram. It is as if three sausage-shaped balloons
were disposed pyramidally--two lying side by side with one
super-imposed, with the bags connected at the points where the
circular sections come into contact. Thus the external
appearance of the envelope is decidedly unusual, comprising three
symmetrical ridges. At the points where the three bags come into
contact cloth bands are stretched across the arcs, thereby
forming a cord. The suspension system is attached to the upper
corners of the inverted triangle thus formed, and converges in
straight lines through the gas space. The bracing terminates in
collecting rings from which a short vertical cable extends
downwards through a special accordion sleeve to pass through the
lower wall of the envelope. These sleeves are of special design,
the idea being to permit the gas to escape under pressure arising
from expansion and at the same time to provide ample play for the
cable which is necessary in a flexible airship.

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