A Second Look At Helicopter Propulsion Problems

Basic theory, developmental programs, and present operational propulsion systems are reviewed with the aim of deriving generalizations which are valid for present evaluation and future planning of helicopter propulsion systems. Certain practical requirements of helicopter powerplants are deduced from the results of actual operating experiences and probable future operational requirements. The need for standardization of terms and performance presentation methods is shown, and suggested methods are reviewed. Additional research work required for tip engines is outlined.