Impact of Rotor Inflow Modeling on Maximum Thrust, and Beyond, of an Isolated Rotor in Hover

Abstract

Comprehensive codes are the working horse for design and simulation of a helicopter and its rotor under steady and unsteady operating conditions and also used to predict their limits until rotor stall occurs. This paper focuses on the prediction of hovering rotor maximum thrust (due to stall limits) and the thrust & power characteristics when the collective control is further increased. The aerodynamic factors that in parts significantly affect the results are: steady or unsteady aerodynamics, steady or dynamic stall, blade tip losses, curvature flow, yaw angle, downwash model, blade-vortex and fuselage-rotor interaction. The downwash model and tip losses are found as most important factors in general.