402 POLAR PROBLEMS 



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 idly wintered in the Arctic it would be better to dismantle and house 

 them in small hangars, assembling them outside just before starting 

 work for the season. They might thereafter be left in the open. 

 During the writer's experience in Alaska snowdrifts did not form 

 beside or behind the high-wing monoplane used, but a drift formed 

 several feet in front of it. About the biplanes drifts formed as high as 

 the lower wing and over the fuselage and tail. 



At the suitable time of the year any machine practicable for 

 reconnaissance work in the Arctic could be flown from points in 

 civilization to an Arctic base of supplies, the expedition thus avoiding 

 not only the expense of wintering in the Arctic but also the possible 

 demoralizing effect that wintering might have on the personnel. An 

 expedition to the Antarctic would carry the planes and the supplies 

 to be used in a vessel to the edge of the continent during early summer 

 and complete the season's work in time to escape the winter conditions. 



Landing Gear for Polar Airplanes: Wheels and Skis 



The design of landing gear for use with airplanes in the Arctic 

 will depend on the area to be visited and the type of work to be done. 

 On the Alaskan, Canadian, and Siberian coasts, where large lagoons 

 and long stretches of level ice, thinly covered with snow, are to be 

 found, and if long out-and-back flights are contemplated, wheels 

 may be used to advantage because they are not so susceptible to 

 damage and afford a speedier take-off. In the writer's Arctic experi- 

 ence it was found safe to land with wheels in snow twelve inches deep, 

 and, while it might be possible to take off with a light load from snow 

 as deep as that, it is better — and little trouble — to clear runways or 

 gutters, just as wide as the tires on the wheels, to a depth that reaches 

 the smooth ice below the snow. When the wheels are placed in the 

 gutters, the machine cannot change direction and, running over the 

 smooth ice, takes off in excellent fashion. 



Where the snow is deep, as in the neighborhood of Greenland and 

 Spitsbergen, it would not be possible to use wheels. When suitable 

 landing gear designed especially for use with skis is available and when 

 suitable skis weighing not more and offering not more head resistance 

 than wheels are obtainable, then skis will offer advantages over wheels 

 for Arctic flying. 



Much investigation is necessary before satisfactory ski equipment 

 will be available. The many variable conditions encountered in 

 snow-covered countries — differences in snow texture, density, tem- 

 perature, and surfaces — demand special equipment designed for the 

 particular district and season involved. 



Snow temperature and texture materially influence the coefficient 

 of friction between the snow and ski surfaces. Friction varies with 



