Maximum Thrust of Helicopter Rotors in Hover: Impact of Comprehensive Code Aerodynamic Modeling

Abstract

Comprehensive codes are the working horse for simulation purposes of a helicopter and its rotor under steady and unsteady operating conditions and also used to predict their limits until rotor stall. This paper focuses on the prediction of hovering rotor stall limits and the aerodynamic factors that in parts significantly affect these: steady or unsteady aerodynamics, steady or dynamic stall, blade tip losses, curvature flow, yaw angle, and the downwash model including free-wake. The downwash model and tip losses are found as most important factors in general and curvature flow effect on stall can increase the maximum thrust.