Learning to fly in the U.S. Army

by E. N. Fales

Fig. 9.—Fuselage diagram, Curtiss “R4” reconnaissance biplane.

Speed 48 to 90 mi. per hr.; climbing ability 400 ft. per min.; 200 h.p.; weight fully loaded 3,245 lbs.

Fig. 10.—An American pusher biplane design.

Crew in front, motor and propeller in the rear, tail support on outriggers.

Single-motor Pusher Airplanes.—The pusher type has popularity because the propeller and motor rotate to the rear of the passenger, who takes his place in the very front of the body and has an open range of vision and gun fire downward, upward and sideways. Another point in favor of the pusher is that the oil and fumes of the motor do not blow into his face as in the case of the tractor. The disadvantage of the pusher is that the motor, being located behind the pilot, will be on top of him in the case of a fall. Another disadvantage is that the body can not be given its shipshape stream-line form because to do so will interfere with the rotation of the propeller. Therefore, the body is abruptly terminated just to the rear of the wings and it is just long enough to hold the passenger and the motor, the propeller sticking out behind. The tail surfaces are then attached to the airplane by means of long outriggers springing from the wing beams at points sufficiently far from the propeller axis so as not to interfere with the propeller.

Fig. 11.—U. S. army battle plane.

Two 100 h.p. motors; speed 85 mi. per hr.

Double-motor Machines.—In order to combine the advantages of the tractor and pusher types and eliminate their disadvantages, the double-motor machines have been developed. In these there is no machinery whatever in the body either in front or back, and the passengers may take seats at the extreme front as is desirable. The body then tapers off to the rear in stream-line form and supports the tail surfaces. The power plants are in duplicate and one is located to each side of the body out on the wings. It is customary to enclose each of these two motors in a casing so that the whole power plant presents a more or less stream-line shape to the wind, the propellers projecting from the front or rear of these stream-line shapes. It may be said that in the double-motor airplane it makes very little difference whether the propeller is in front or behind so that while a “twin-motor” machine may be more accurately specified as a “twin-motor pusher” or a “twin-motor tractor,” it is usually sufficient indication of a machine’s characteristics to call it a twin-motor machine.