MAJOR problems that have been encountered in the operation under contract of that portion of the Transcontinental Air Mail line between Chicago and San Francisco are outlined and discussed briefly.
The more serious difficulties cited are: first, the operation of a single type of airplane from points at altitudes as great as 6400 ft. as well as at sea level, together with the fact that, in the case of this particular line, the heaviest loads are carried between the points of greatest altitude; second, the proper design of cowling and manifolding for the operation of the air-cooled radial engine at the extremes of temperature that are encountered throughout the year; and, third, the need for an engine that is geared down to the propeller or an engine delivering its normal power at a lower engine-speed.
Minor problems listed are: first, the proper manifolding for the air-cooled engine to serve as a muffler, to prevent flare at night, and to provide a means of heating cabins and cockpits; second, the arrangement of the airplane to facilitate quick servicing and loading as well as safety for the crew and passengers; third, proper positioning of fuel tanks; fourth, design of the landing gear; and, fifth, the operation of the landing lights.
Possible solutions for the difficulties are stated, and the results of operation or preliminary experiment, so far as they have been carried, are discussed. Brief comparison is made of the relative advantages of the monoplane and the biplane for transport service.
Discussion relates to the substitution of a wheel for the tail-skid and to details of racing airplanes.