214 



The National Geographic Magazine 



THE MOTORS AND ENGINES 



From the first I was determined not to 

 attempt the voyage with a single motor, 

 though that would represent the greatest 

 economy of weight in relation to effi- 

 ciency. If we carried but a single motor, 

 and that were to break down, we should 

 be left helpless. Thenceforth we could 

 only drift with the wind, as the brave 

 but unfortunate Andree did in his balloon. 

 Santos-Dumont, who has been so helpful 

 with counsel out of his store of expert 

 ence that I owe him a large debt of grati- 

 tude, advised me to take four motors, 

 each of 25 horsepower, working one, two, 

 three, or four, according to circumstances 

 and needs. But my choice, after long 

 consideration, fell on two motors, one of 

 50 horsepower and the other of 25, with 

 a smaller one of 5 horsepower to work 

 the ventilator which inflates the balloonet. 

 Engineers Godard, Andre, Hervieu, 

 Liventaal (all associated with the expe- 

 dition as contractors or as employees) 

 and other experts indorsed my decision. 



If one motor were to break down in 

 the field we have another in reserve. 

 If we need full speed we can work both 

 motors together. If a less speed is 

 considered sufficient for the hour, we 

 can use the 50 horsepower motor alone. 

 If the circumstances justify a still 

 smaller rate of progress (and greater 

 economy of fuel in proportion to the 

 distance covered), the 25 horsepower 

 motor may be worked while the larger 

 one is idle. 



In case of breakage of one of the 

 motors beyond repair (we shall carry 

 tools and a small machine shop, pre- 

 pared to make all ordinary repairs in 

 the field), the permanently disabled 

 motor may be thrown overboard, light- 

 ening ship. 



Another advantage of having two en- 

 gines and two screws is that while the 

 best of the modern inner combustion 

 motors may be prudently worked many 

 hours without stopping, it is our pur- 

 pose to take no risks of overheating 

 through too long continuous running, 



but to stop each motor once in three 

 or four hours for inspection and cool- 

 ing. While one is idle the other may 

 be worked. 



Again, I stipulated in the contract 

 that for the principal or larger propul- 

 seur and its shaft we should have re- 

 serve parts — another screw and another 

 shaft, all so arranged that in case of 

 accident to one it may be taken out and 

 thrown away and the reserve be fitted 

 in its place. Hence we have in our 

 motive department two motors and 

 three screws and shafts, all of which 

 must be permanently disabled before 

 our navigating power comes to an end. 



Considering the average, 12 geo- 

 graphical miles per hour is the speed 

 we expect to attain. This should be 

 secured with an average of about 40 

 horsepower in operation. It is true 

 that we shall never positively and ac- 

 curately know what speeds we are to 

 attain until we have the trials of our 

 airship, and these trials we hope to have 

 in Spitzbergen next July. But the con- 

 tract with Constructor Godard calls for 

 the following: efficiencies of the motors : 



Motor in op- 

 eration. 



Propulseur. 



Meters per 

 second. 



Kilom. per 

 hour. 



Statute miles 

 per hour 



Geographical 



miles per 



hour 



50 H. P 



Large. 

 Small. 

 Both. 



6.67 

 4.72 

 8.88 



24 j 14.91 

 17 j 10.56 

 32 19.88 - 



12.94 

 9.17 

 17.27 



25 H. P 



75 H. P 



M. Godard has no doubt we shall be 

 able to realize these speeds. It is not 

 my proper function to pass judgment, 

 but to go into the field and learn 

 through actual trials how well he has 

 worked up to his contract obligations. 

 M. Godard is a conservative, careful 

 man, and I have much faith in him. 



With proper speeds of from 9 to 17 

 geographical miles per hour at our 

 command, we shall be able to cope 

 with approximately eleven-twelfths, 

 certainly four-fifths, of all the winds 



