High Fidelity Helicopter Simulation using Free Wake, Lifting Line Tail, and Blade Element Tail Rotor Models

This paper describes the development of high performance empennage models for general-purpose free flight helicopter simulation. A lifting line horizontal stabilizer model and a blade element tail rotor model were developed for the Sikorsky general helicopter simulation (GenHel), and integrated with an advanced freewake based main rotor downwash model from Continuum Dynamics Incorporated (CDI). In addition to increased fidelity over conventional simulations, a more physical based interface was developed with a minimum of reliance on empirical data/corrections. Simulation runs were made for forward and sideward level flight speed sweeps, and normal approaches to hover, showing excellent correlation with flight test data from the Sikorsky S-92, and UH-60L aircraft.