The Polar Airship 



217 



ratus by having it subjected to strains 

 greater than it is able to withstand. The 

 maximum strain provided for can never 

 be exceeded, no matter what the force of 

 the wind. The balloon can never be sub- 

 jected to the stress, the pounding, the 

 violent vertical plunging such as would 

 occur in firm anchorage, where there 

 must be a constant effort on the part of 

 the aeronef to find adjustment between 

 the two forces — one a horizontal pull, the 

 other the lifting power of the balloon. 

 There would be no danger of being 

 thrust down near to or into contact with 

 the ice. All strains would be cushioned, 

 yielding, "giving," with the driftage of 

 the vessel. 



It is not necessary to go into details 

 concerning the mechanical aspects of the 

 retardateur. In fact, several methods of 

 securing resistance will be tested at Spitz- 

 bergen, and the one which gives best re- 

 sults will be finally chosen. 



An important consideration is the 

 method of operating the retardateur; 

 also its point of suspension. If it were 

 payed out from a windlass in the open 

 boat below the car, as we had at first 

 planned, the result would be that the 

 angle of its pull would run according to 

 the line A-B-C in this diagram. 



In other words, the pull of the drag- 

 anchor on the ice at A would be trans- 

 mitted through the steel boat at B to the 

 rear end of the balloon at C. The airship 

 would be turned round. Its stern instead 

 of its prow would be presented to the 

 wind. After full discussion of this sub- 

 ject with M. Santos-Dumont,who has had 



more experience in guide-roping and 

 similar work than any one else, and who 

 gave us the full benefit of his practical 

 knowledge, it was decided to adopt the 

 method of suspension and operation 

 shown in figure 3. 



Avowee. ?>. 



The retardateur cable is suspended 

 from the prow of the balloon at A, from 

 which point bands of fabric of high ten- 

 sile strength are passed over the body of 

 the aeronef — A- A' A' A' A' — to dis- 

 tribute the stress. 



When the retardateur is not in use it 

 hangs from its operating pulley, B, free 

 from contact with the ice, and out of the 

 way of any possible interference with the 

 forward screw. When it is desired to 

 put it to work it is lowered by means of 

 the line D D D working over pulleys 

 down to a windlass in the steel boat. The 

 moment it strikes the ice and the aeronef 

 drifts backward, the angle of the re- 

 tardateur cable follows the dotted line. 

 All the pull of the drag-anchor at E is 

 thus exerted upon the forward part of 

 the balloon, and the aeronef always keeps 

 its prow to the wind. If the wind shifts, 

 the balloon turns with it like a weather- 

 vane. 



When the wind moderates and the use 

 of the retardateur is no longer needed, 

 and the motors are started, the cable is 

 pulled in by the windlass till it once more 

 hangs vertically at C. 



This is the method we have adopted 

 for minimizing the driftage in strong ad- 

 verse winds — the method which we be- 

 lieve will enable us to take full credit 

 value from all favorable winds and to cut 

 down materially without expenditure of 

 fuel the losses inevitably incident to un- 

 favorable winds. 



