The Polar Airship 



213 



all the winds we should expect, from the 

 means of probability, to encounter. 



To be able to meet and overcome all 

 winds, we should have to be equipped 

 with motors and screws giving at least 

 30 miles per hour. 



Was this last-named speed attainable? 

 Theoretically, yes ; practically, no. I 

 shall try in a few words to make the 

 answer plain. Resistance of a body mov- 

 ing through the air increases, as we all 

 know, not with the speed, but with the 

 square of the added velocity. I took the 

 best formula — that of the late Colonel 

 Renard, whose brother, Commandant 

 Renard, was one of my valued counselors. 

 I compared the formula with the actual 

 experiences of La France, the Lebaudy, 

 the Santos-Dumont and other successful 

 airships. I found that for a speed of 10 

 geographical miles per hour we should 

 need about 20 horsepower; for 12 miles 

 per hour, about 40 horsepower; for 17 

 miles per hour, about 75 horsepower ; but 

 that for 30 miles per hour at least 400 

 horsepower would be required. 



Now, it would be possible to put motors 

 of 400 horsepower into our airship. We 

 have at our disposal for machinery, cargo, 

 fuel, and crew about 8,500 pounds. Mo- 

 tors can be built at about 7.5 pounds per 

 horsepower ; hence we should have to put 

 at least 3,000 pounds of our weight into 

 motors. The crew, provisions, instru- 

 ments, etc., must weigh 3,000 pounds, and 

 at the utmost 2,500 pounds would be left 

 for gasoline. As each horsepower hour, 

 represents a consumption of 0.7 pound of 

 gasoline, or about 0.85 pound, including 

 the reservoirs and the lubrication, every 

 hour the 400 horsepower motor was 

 worked would cost about 350 pounds in 

 fuel and other weight. For that 350 

 pounds we should gain 30 miles, or nearly 

 12 pounds per mile. The distance to the 

 Pole and return being about 1,200 miles, 

 this plan would call for about 14,000 

 pounds of gasoline, and then we should 

 have no margin over the actual distance 

 in a straight line from Spitzbergen to the 

 Pole and back again. 



True, we might build a larger airship. 

 But the larger the ship, the more resist- 

 ance to be overcome. It might be pos- 

 sible, by constructing an airship five times 

 larger than ours, at a cost of a million dol- 

 lars, to secure a speed of 25 to 30 miles 

 per hour, and fuel capacity sufficient to 

 voyage to the Pole and return; but I 

 doubt it. At any rate, such speeds are 

 wholly impracticable in our venture. 

 And, fortunately, they are not required 

 for a successful outcome. 



One of the ablest of the aeronautic 

 engineers of Paris came to see me, after 

 my decision as to speed and method had 

 been announced in the French news- 

 papers. 



"Your plan is all wrong," he declared; 

 "I have come to tell you that you will 

 surely fail if you adhere to that method." 



"What do you recommend ?" I asked. 



"High speed — go quickly as possible — 

 leave all contact with the earth by means 

 of the guide-rope — sail high in the air, 

 and make a fast voyage up and back." 



"At what speed?" 



"You should make at least 15 meters 

 per second with your motors — 55 kilo- 

 meters per hour." 



I asked my friend to sit down and 

 figure out the weight of the motors that 

 would be required to yield this speed, 

 equal to about 30 geographical miles per 

 hour, and the amount of fuel that would 

 be required, remarking that I was afraid 

 he had not sat up nights with the problem 

 as much as I had, and at the same time 

 handing him my computations. He ran 

 over them, saw that they were approxi- 

 mately correct, and, like a gentleman, 

 acknowledged his mistake, saying, "You 

 are right, and I was wrong." 



Having reached the conclusion that 

 speeds of 25 to 30 miles per hour were 

 impracticable and unnecessary, there 

 arose the secondary question, What is 

 the highest speed we shall try for? This 

 was involved, also, in the question of the 

 number of motors, their horsepower, and 

 the number and emplacement of the 

 helices or screws. 



