Computer Flight Testing of Rotorcraft

This paper describes a recently developed analytical tool for computer ‘flight testing’ of VTOL designs. Steady state flight, maneuvers, gust response, and weapon recoil effects are evaluated so that required configuration changes can be made early in the pre‐design phase. This objective is achieved by detailed representation of the aircraft including rotors, wings, auxiliary propulsion and control systems. Complete blade element analyses of the main rotor, tail rotor, and propellers are performed throughout the maneuver based on the instantaneous aerodynamic and dynamic environment. Time histories of main rotor blade loads and bending moments are calculated. The basic equations and programming procedures are presented and discussed. Details are given concerning the representation of airframe and rotor parameters, the types of maneuver inputs and the output format available to the engineer. Examples are given of typical cases studied, including a full autorotative landing, and a high‐performance deceleration using reversed propeller thrust. Improvements which are in work and planned refinements are also discussed.