Mathematical Simulation of a Vibrating Light Aircraft Piston Engine and Correlation with Engine Flight Test Data 740383

Piston engines used in light aircraft occasionally experience extreme in-flight vibrations, especially while driving a two-bladed propellor during a severe yaw maneuver. This paper provides experimental evidence that this condition can be avoided by the judicious selection of the propeller and propeller shaft masses and stiffnesses. The paper also describes a digital computer program which successfully predicts the engine speed at which resonance will occur for a given propeller-engine combination. Because new airframe applications require the successful matching of both the engine and the propeller to the airframe, this program could provide airframe, propeller, and engine manufacturers with mutually acceptable solutions to their respective design requirements.