June 26, 1915. 
LAND AND .WATER. 
THE WAR IN THE AIR. 
IS THE ZEPPELIN INVINCIBLE? 
By F. A. Talbot. 
THE recrudescence of a certain Zeppelin liveliness 
upon the Eastern coast, and the escape of the 
aerial invader, has once more revived the parrot- 
cry, " Where are our defending aeroplanes and 
anti-aircraft guns 1 " The fact that these corsairs 
•f the skies invariably complete their fell work of distributing 
death and destruction without suffering any mauling in the 
process has created a distinct feeling of uneasiness in the 
minds of the more timorous, who are beginning to wonder 
whether, after all, the Zeppelin is not invested witli extra- 
ortKnary properties of invulnerability, and will be able to 
exercise the command of the air ! As a matter of fact, it has 
come to be regarded in some quarters as a kind of super- 
dirigible, and a meed of abuse is being meted out concerning 
the supiness of our authorities in accepting the general 
opinion of this craft as a " mechanical monstrosity," and 
thereby underestimating its qualities. 
The brilliant exploit of the late Lieutenant Warneford, 
V.C, in successfully sending a Zeppelin and its crew to their 
last account has served to revive drooping spirits to a certain 
degree, and has proved that the Zeppelin is no more immune 
from attack than any other vessel. Incidentally, it has been 
responsible for the inquiry as to why our defending airmen 
cannot do likewise. 
No vessel is easier to destroy in theory than the Zeppelin, 
owing to its enormous bulk. The latest craft measure 525 
feet in length, by some 30 feet beam, so that a huge target 
is offered to hostile fire. In actual practice, no airship is so 
difficult to put hors Je combat, the size of the target notwith- 
standing. As a matter of fact. Lieutenant Warneford in his 
feat demonstrated the only effective means of sending these 
vessels to destruction — bj/ fjetllng above them, and lannchiiig 
a bomb to ir/riile the ffa^eoiis cha/ffe with uhic/i the hnr/e gas- 
hag is inflated, which, owing to jts pronounced lifting power, 
is hydrogen. Parenthetically, it may be observed that 
Warneford in his achievement exposed another German bluff. 
The vessel he destroyed was one of the latest, which, accord- 
ing to sedulously disseminated Teuton intelligence, was in- 
flated with a non-inflammable gas ! 
From the meagre details which have been published, it is 
difficult to realise how Lieutenant Warneford succeeded in 
gaining the advantage of position — that is, a point above the 
airship. It appears to be a straightforward operation to race 
upwards through the air to gain paramount position. The 
average individual would lay the odds upon the aeroplane, 
in view of the extreme altitude to which a pilot has driven 
his machine, as, for instance. Hawker's record of 20,000 feet, 
and from the fact that the heavier-than-air machine can 
attain a far greater altitude than the Zeppelin, the safe limits 
of which are about 12,000 feet. But in " climbing," if such 
a term may be used, the speed advantage is with the airship. 
The dimension in which the airship excels is the one in which 
the powers of the aeroplane fall to the minimum. In other 
words, the airship is able to take the utmost advantage of the 
aeroplane's most pronounced weakness. The latest types of 
Zeppelin have an ascensional speed of 3,000 feet per minute, 
which is equivalent to an average of thirty-four miles an 
hour. The mention of the latter figure may seem superfluous, 
but the reason therefor I will explain later. Moreover, it 
moves in this plane in a direct vertical line — that is, upon an 
even keel. On the other hand, v^hen the aeroplane desires to 
make a rapid ascent, resort must be made to " spiralling," 
and in this operation, although the speed may be maintained, 
progress in the vertical direction is relatively slow, as those 
who have attended an aerodrome have observed when an air- 
man sets out deliberately to climb as fast as possible to a 
certain height, in order to " loop the loop." 
The Germans have always recognised that the tactical 
position for effective attack upon a Zeppelin is directly above, 
and accordingly special attention has been devoted to nullify 
the attainment of this position as much as possible. The 
Zeppelins have been given as high an ascensional velocity as 
the structure of the metal framework will permit, and, be it 
noted, this maximum speed must not be approached except in 
instances of dire emergency, inasmuch as the vessel, when 
flying upwards at such a velocity, is submitted to enormous 
strains, which exert severe shearing stresses upon the metallic 
framework. All vessels are submitted to the ascensional test, 
and these are of sufficient severity, according to my source of 
information, sm to cause, occasionally, severe shearing of the 
bolts holding the framework together. The various girders 
are induced to move so seriously as to cut the heads and nuts 
off the rivets as cleanly as if severed by a pair of shears. 
An ideal position for attacking an airship which is 
moving in the vertical jjlane is one immediately below the 
ail-ship, since the guns and rifles on the latter cannot be 
depressed sufficiently to hit the comparatively small target 
offered by the heavier-than-air machine. On the other hand, 
the men in the latter are not particularly hampered by being 
forced to fire directly upwards; it is no more trying than 
shooting at pheasant-s passing overhead. So far as the 
men in the aeroplane are concerned, their objective, when 
attacking from this position, is rather the disablement of the 
propelling machinery and the killing of the crew than the 
hitting of the gasbag itself. The latter cannot be damaged 
seriously bij girn--fire. The system of compartmenting, or sub- 
dividing the vessel into eighteen compartments, each of which 
contains a hydrogen-inflated balloon, nullifies this form of 
attack very completely. A bullet will merely make two punc- 
tures — one where it enters and the other where it emerges 
from the balloon respectively. In its flight the missile will 
not fire the gas. The punctures in the envelope will be so 
small that, although a gas leak will be precipitated, the 
exudation of the inflating agent will proceed so slowly as to 
affect the airship very slightly, and even this loss can be 
counterbalanced by the discharge of ballast. 
On the other hand, if the machinery can be put out of 
action, even only partially, success is imminent. Directly 
the airship becomes deprived of its independent speed — that 
is, the speed developed by the motors, and which exceeds the 
velocity of the air-currents, thereby enabling the vessel to 
move in any direction — it reverts to the status of the ordinary 
balloon. It becomes the sport of the wind. Its pursuit, 
attack, and ultimate destruction are simplified very appreci- 
ably. It cannot dodge its pursuers because it is able to move 
only in one direction — that of the wind. Its position is 
rendered additionally precarious because, under such con- 
ditions, its immense dimensions and weight contribute to its 
peril. It will plunge and roll to such an extent as to set up 
destructive internal strains, and, if it does not break its back, 
it will tumble head foremost to the ground. The first Zep- 
pelin loss in the war, which occurred in the Vosges as a result 
of direct attack, was attributable to the disablement of the 
machinery. Absolutely uncontrollable, the monster plunged 
finally into a forest to roll over and sprawl itself among the 
trees. 
But if the attacking aeroplane secures command of 
position so that it get-s immediately above the Zeppelin, the 
latter can scarcely hope to escape destruction, because it is 
exposed to the only missile which is capable of firing the 
hydrogen with which it is inflated — the bomb. Even in this 
extremity the Zeppelin has one possible avenue of escape, but 
it is of a desperate character. This is to take avail of its 
speed in the vertical plane in the reverse direction — to 
descend rapidly. This end can be consummated only by 
releasing a vast volume of gas, and must be carried out care- 
fully so as not to disturb the dynamic equilibrium or longi- 
tudinal stability of the vessel. It must descend upon an even 
keel. But this final move is made in the hope of catching the 
aeroplane overhead napping. Fearing that his prey may 
escape him, the aviator, in his attempt to keep within easy 
distance or point-blank bomb-dropping range of his foe, may 
overshoot the mark and thus lose his command of position. 
Should this occur, the Zeppelin is arrested in its downward 
descent, and by hurriedly discharging objects overboard pell- 
mell, a sufficient reascending effort may be imparted to enablvs 
the airship to regain superior position. This was evidently 
the ruse which was put into execution by the commander of 
the Zeppelin destroyed by Lieutenant Warneford. Unfor- 
tunately for the Zeppelin the aviator kept his head, and 
merely descended sufficiently to make sure of his bomb. 
But manoeuvring under and also above a Zeppelin must 
be conducted with extreme caution. In flying upwards at 
the speed of 3,000 feet per second, a terrifying vortex is pro- 
duced beneath the airship, and, if the aeroplane should be 
engulfed, its own destruction is certain. Some idea of the 
character of this vortex may be readily gathered by standing 
upon the platform of a railway station to watch a train pass- 
ing at the speed of 34 miles an hour, which is equivalent to 
that of a Zeppelin ascending at 3,000 feet per minute. Tiia 
13* 
