Abstract: The whirl flutter stablility of the engine-propeller installation is related to the aircraft with propeller, turboprop, or propfan engines. In this paper a practical method is presented to analyse the problem. In the analysis four degrees of freedom, namely vertical and horizontal displacements, pitch and yaw, are considered. Quasi-steady propeller aerodynamics and gyroscopic moment are added to the dynamic equation. From the system slate equation obtained . eigenvalues, eigenvecters are abstracted to predict and analyse the system's stability. Based on an example data, the effects of several parameters on the stability are also studied.

Key words: acroelasticiy, whirl tlutter, stabiiity. propeller