The Economic Speed-Weight Relation in Air Transportation

POINTING out that the fundamental object of securing speed, economy, safety and comfort is the same irrespective of the form of transportation used, the author emphasizes the necessity of establishing a balance among these more or less conflicting desirable factors of performance and determining just what that performance may be. The specific basic assumptions upon which the calculations of the paper are made are stated as being that an airplane cruises at 85 per cent of its maximum speed; that two-thirds of the maximum rated horsepower is consumed in level cruising-flight; fuel for a 400-mile flight is carried; the total weight of the powerplant is 2.5 lb. per hp.; weight of the airplane structure is 33 per cent of the total weight carried; and the pay-load is assumed to be two-thirds of the figure remaining after subtracting the structure, the powerplant, and the fuel weight.

The various points covered include the relations of pay-load to engine horsepower, initial cost of airplane and engine, costs per pound of pay-load and per passenger-mile, value of the time saved by greater speed, and the possibilities of increased cruising-speed. Five means for securing higher cruising-speed are listed. A number of charts and tables supplement the paper.