DEVELOPMENT OF AN ADVANCED PILOTED HELICOPTER SIMULATION

The advantage of piloted simulation in the design of control systems and evaluation of handling qualities is well established, provided the simulation is sufficiently sophisticated to model highly coupled nonlinear regimes of flight. This paper describes the development of an advanced piloted helicopter simulation with improved fidelity in the mathematical model. Special emphasis is placed on the vector approach used in the multimode blade element aeroelastic rotor model, the intercomponent interface, and the interface between the flight model and the hardware in the loop. Early decisions to use a specialized simulation computer to perform the high-frequency model calculations and a slower but more robust mainframe to calculate the low-frequency and/or evolving parts of the model increased overall execution speed and enhanced the accuracy of the model. Further design decisions to use the same model for realtime and off-line analysis led to additional capability in loads prediction and sub-system selection. Correlation of this model with other, more sophisticated nonrealtime models is shown to be good in hover, forward flight, and nonlinear regimes such as high-speed and high-descent-rate flight.