Longitudinal and Lateral Control Sensitivity Damping Analysis for Larger Rotorcraft in Helicopter Mode

A mathematical study was undertaken with larger rotorcraft in an effort to establish possible effects of vehicle size on minimum acceptable control response in helicopter mode. Simulation results demonstrate the validity of a proposed reduction of these longitudinal/lateral control power parameters with increase in vehicle size. In the pitching axis, control sensitivity and angular velocity damping characteristics, which provided acceptable maneuvering capability, do not require increasing very much for larger rotorcraft in order for Handling Qualities Level I to be approached. However, the rolling axis results indicate that lateral control power is required to be higher than that of the ADS-33PRF-specified value, in order to maintain lateral maneuvering capability. These results show the need for considering the damping in combination with the pitching and rolling control sensitivity when control-response criteria are applied for design purposes or when MIL–H–8501A specifications are used to determine minimum acceptable response characteristics for VTOL vehicles.