THE POLAR AIRSHIP 



By Walter Wellman 



AIRSHIP construction and opera- 

 tion is an art which has not 

 made much progress in this 

 country, although Knabenshue, Bald- 

 win, and perhaps others have done in- 

 teresting and valuable work on a small 

 scale. In this country the prevailing- 

 conception of an airship is that of a gas 

 bag of small size, relatively, covered 

 with a netting of ropes or steel wires, 

 and with sufficient lifting capacity, 

 when inflated with hydrogen gas, to 

 carry the balloon, a light framework of 

 bamboo or wood, one or two men, and 

 a small motor, with a sufficient supply 

 of fuel to run it for a few hours. 



The dirigible which M. Godard and 

 his corps of experts have in hand is an 

 entirely different sort of affair. Its 

 great size enables it to lift not only the 

 balloon, but the car of steel, the three 

 motors, comprising a total of eighty 

 horsepower, two screws or propulseurs, 

 a steel boat, moto-sledges, five men, 

 food for them for seventy-five days, in- 

 struments, tools, repair materials, lubri- 

 cating oils, and 5,500 pounds of gaso- 

 line for the motors. It will be seen that 

 in its cargo capacity our ship of the air, 

 with its eight tons of carrying power, 

 much more resembles a vessel to navi- 

 gate the water than the small contri- 

 vances used by Santos-Dumont, Kna- 

 benshue, and Baldwin in aerial experi- 

 mentation. 



The instructions given by me to M. 

 Godard, and embodied in the contract, 

 were to spare neither weight nor ex- 

 pense in his efforts to make a balloon 

 that should give the maximum of se- 

 curity and endurance. It is commonly 

 believed among the aeronautic experts 

 of France that the unfortunate Andree 

 met his fate partly through faulty con- 

 struction of his balloon ; that it lacked 

 the gas-tightness which should have en- 

 abled it to remain a long time in the 

 air, and that the fabric of which it was 



composed did not possess sufficient ten- 

 sile strength to enable it to resist the 

 elements and give its navigators a fair 

 chance for their lives. I pass no judg- 

 ment as to this, because I believe the 

 builder of Andree's balloon, who is now 

 dead, was a careful and conscientious 

 man. But, at any rate, I was deter- 

 mined to avoid such mistakes if care 

 and prudence and outlay could suffice 

 to do it. For in one particular, and in 

 one only, speaking broadly, is our en- 

 terprise comparable to that of Andree — • 

 the solidity and endurance of the gas- 

 bag is as essential to us as it was to 

 him, despite the fact that his aerial 

 craft was a mere toy of the winds, with- 

 out motive power or steerability, while 

 ours is to have both. 



the) material used 

 In the past most balloons have been 

 made of silk, varnished with from two 

 to five coatings ; but in recent construc- 

 tions of important character cotton tis- 

 sues have been employed, in one or 

 more thicknesses, coated with a thin 

 film of pure rubber applied by means of 

 special machinery similar to the calen- 

 ders of paper mills. The Lebaudy air- 

 ship had two tissues of this cotton, both 

 rubbered. After careful consideration 

 and elaborate calculations of pressures 

 and strains, three thicknesses of fabric 

 were decided upon for our ship — two of 

 cotton material and one of silk — with 

 three coatings of rubber. All three are 

 consolidated into one fabric, giving 

 great tensile strength. Counting from 

 the interior of the balloon, the envelope 



is made Up as follows: Grammes Ounces 



per sq. per sq. 



meter. foot. 



Strong silk 85 .278 



Caoutchouc (Para pure) 105 .344 



Cotton 105 .344 



Caoutchouc 65 .213 



Cotton 100 .328 



Caoutchouc 45 .147 



Total. 



SOS 



1654 



