THIS paper contains a brief discussion of the advantages inherent in a rotating-wing aircraft in regard to its performance and safety as compared to the conventional airplane. An arbitrary criterion is set up that presents the different characteristics which must be possessed by the rotating-wing aircraft in order that it be considered successful and practical, and the criterion is then used to evaluate the merit of the helicopter, the cyclogiro, the autogiro, and the gyroplane.
According to the criterion, the autogiro and gyroplane will be superior to the airplane when their pronounced possibilities for high-speed performance are materialized, these possibilities consisting of the inherent ability of the autogiro and gyroplane rotors to attain their maximum lift-drag ratio at any desired forward speed. The cyclogiro is approximately equal in merit to the airplane, while the helicopter is quite definitely inferior.
The discussion indicates the utility of the rotating-wing machine for the private flyer and the unskilled pilot, because of its increased safety and the smaller landing field required for it.