Rotorcraft Simulation Model Enhancement to Support Land and Sea-Based Testing and Operational Analysis

This study addresses model enhancements to rotor wake modeling that significantly improve the prediction of helicopter behavior across the flight envelope. Specifically, the model enhancements have been made to include the tip vortex distortion effect in the finite state dynamic wake model to improve the poor prediction of rotorcraft off-axis response. The enhanced formulation allows for better prediction of aerodynamic interference. This includes the rotor aerodynamic interference on fuselage and other lifting surfaces. A modification of the finite state dynamic wake model has also been made to include the vortex ring state. The resulting simulation is applicable across the flight envelope. The enhanced model has shown a remarkable improvement in the prediction of helicopter response in both hover and forward flight.