CHAOTIC STALL RESPONSE OF HELICOPTER ROTOR IN FORWARD FLIGHT

A typical evolution process for rotor blade stall response from periodic to aperiodic or chaotic motion and a necessary condition for the onset of chaotic response are discussed. This is the first such study of chaotic motion due to aerodynamic stall of a helicopter blade in the literature. For this study, the ONERA nonlinear aerodynamic stall model is applied to the analysis of helicopter blade stall response. Nonlinear state variable equations and linear state variable perturbation equations are derived and solved. Also, a comparison between the results from the ONERA stall and a simpler nonlinear aerodynamic model is made. © 1992.