

THE INDIA RUBBER WORLD 



April 1. 1915. 



The Part That Rubber Plays in Military Aviation. 



WHATEVER maj have been the popular opinion as to the 

 military value oi the flying machine prior to Julj of 

 last year, there can be no doubt about the important 

 pari thai aeroplanes have played in the world war. Necessity 

 has compelled the air pilot to take seemingly desperate tasks, 

 and in doing this he has gained confidence in his craft and lias 

 found mam ways in which he could use his vehicle to the ad- 

 vantage of Ins fellow lighters moving upon the ground. 



[Today, the warring nations arc striving in every way to ob- 

 tain more aeroplanes, for quite apart From the offensive value 

 ot these mechanical birds of man's making, they have the gift 



tconnoitring, which either compels extreme efforts towards 



ecj on the part of the foe or, this failing, reveals the an- 

 tist's positions and thereby facilitates certainty oi attack 

 In short, the living machine has more than once broken up the 

 strategic moves of the foe and in this manner has made it more 

 and more difficult for an enemy to surprise. Indeed, it may 

 justly be said that this method of aerial scouting has played a 

 conspicuous part in prolonging the war, because one army's con- 

 centration for assault at a supposedly weak point has been 

 promptly met by ample defenders, all because of the spying 



from above. 



Today, because of strict censorship, it is quite impossible to 

 tell just what is the aeroplane h rce of the various nations. But, 

 at the beginning of the conflict, the most reliable data gave the 

 following approximate figures regarding heavier-than-air flying 

 machines: France had 1.400 aeroplanes; Germany. 1,000; Rus- 

 sia. 800; Great Britain, 400; Austria, 400; Belgium, 100; and 

 Servia, 60 aeroplanes At the same time, the United States 

 could boast the unpretentious array of 23 aeroplanes in the 



The Pilot of a German Seapi \m Protected by a Combined High Flight ash 



Submarine Respirator. 



army and navy combined. In the matter of airships or naviga I 

 balloons, commonly called "dirigible-" the comparative resources 

 were as follows: Germany. 40 dirigibles; France. 22; Russia, 

 18; Great Britain. 9; Austria. 8. and Belgium. 2 dirigibles. Like 

 Mother Hubbard's cupboard, our air fleet contained none of 

 these. 



While German) from the very beginning of hostilities has 



promised to use her Zeppelin dirigibles offensively and with very 

 disastrous effects, the tact remains that these airships have not 

 figured tellingly Up to date, although they have done a minor 

 measure of damage at widely separated periods. But, however, 

 while the Zeppelins have failed to live up to their dire threat, 

 there is no question about the effective work that the dreaded 

 " Tauben" t which means "doves"; of the Kaiser's armies have 

 done from time to time. As air scouts and as offensive instru- 

 ments of war, these flying machines have rendered good ac- 

 count of themselves from the beginning, and their pilots, like 

 those of their rivals, have taken desperate chances in order that 

 this arm of the service might prove its worth. 



Undoubtedly the most interesting way in which rubber enters 

 into aviation is its use in the respiratory apparatus, which makes 

 it possible for the aviator to work under atmospheric condi- 

 tions that normally would render him absolutely helpless. This 

 phase will be described in detail further on. But first consid- 

 eration may properly be given to the part that rubber plays in 

 the construction of the flying machines themselves. It plays a 

 conspicuous part in both the airship and the aeroplane. True, 

 the Zeppelins use less rubber than other types of dirigibles, be- 

 cause they belong to the so-called "rigid" class, having an ex- 

 ternal envelope of thin fabric with an aluminum coating, within 

 which are a number of small balloons made of goldbeater's skin 

 — the outside membrane of the large intestine of the ox. But 

 the majority of dirigibles are of the "non-rigid" type; i. e., their 

 envelopes are flexible and are given a measure of semi-rigidity 

 by means of the pressure exerted outward by the buoyant hy- 

 drogen gas. For the non-rigid ships rubberized fabric must be 

 used, and while the leakage through this material averages about 

 one per cent, in twenty-four hours, 

 still it is the best fabric attainable — 

 elasticity under pressure being a pre- 

 requisite. The semi-rigid type is 

 really a modified non-rigid dirigible, 

 and here, again, rubberized material 

 is demanded. 



As the layman will readily grasp, 

 it is of vital importance that the en- 

 velopes should be tough and not lia- 

 ble to tear easily. Accordingly, in 

 the navigable airships of today the 

 fabric is a composite affair, made 

 up of several layers of cloth with 

 layers of rubber intervening. This 

 material is pressed together and vul- 

 canized. Then the stuff is cut to 

 various shapes as the construction of 

 the aircraft demands. In the build- 

 ing of the non-rigid airships for 

 England, the so-called "Continental" 

 fabric used for the envelope is a dou- 

 ble diagonal rubberized material, and 

 this is treated with chrome yellow- 

 externally to shield the rubber from 

 the effects of sunlight. All seams 

 are gummed with rubber cement. It 

 is said that it is easier to repair the envelope of the non-rigid 

 airship than to mend the outer covering of a Zeppelin. Indeed, 

 while the elastic envelope seldom lasts more than three years, 

 still it can be replaced at a comparatively moderate outlay — 

 estimated at less than $2 per square meter. It is the practice 

 to place the warp and weft of rubberized fabrics so that the 

 threads of each layer are diagonal to those of the contiguous 



