Engine/Airframe Interface Dynamics Experience

Recent experience has highlighted the necessity for improved understanding of potential engine/airframe interface dynamics problems to avoid costly and time-consuming development programs. This paper gives some examples of such problems, and the manner in which they have been resolved. It also discusses a recent program in which contractual engine/airframe interface agreements have already proven helpful in the timely prediction and resolution of potential problems. In particular, problems of engine/ drive system torsional stability, engine and output shaft critical speeds, and engine vibration at helicopter rotor order frequencies are discussed, and test data and analyses presented. A l s o presented is a rotor/drive system dynamics problem not directly related to the engine.