Shipboard Helicopter Gust Response Alleviation Using Active Trailing Edge Flaps

Helicopter shipboard launch and recovery operations can result in high pilot workload due to the unsteady, turbulent ship airwake. Successful gust response alleviation could improve safety and potentially expand operational envelopes. The results of a feasibility study of using active trailing edge flaps as gust alleviation mechanisms are presented in this paper. The benefits of on-blade actuation and previous swashplate-based gust alleviation control methods are combined, yielding a system that uses trailing edge flaps for gust disturbance rejection while the swashplate provides primary flight control. The controller is implemented in the GENHEL flight simulation model of the UH-60A Black Hawk with a CFD airwake solution for an LHA-class ship. Simulations are performed in hover. Results indicate that trailing edge flaps are capable of alleviating the magnitude of the vehicle angular gust response in the roll and pitch axes, including reduction in uncommanded roll rate of as much as ninety percent in specific wind-over-deck conditions and a reduction in uncommanded pitch rate of up to thirty-two percent. While achieving the performance of a similar swashplate-based controller, trailing edge flap deflection requirements can be kept below current actuation technology stroke and rate limits. The results of this study suggest that trailing edge flaps can be effective for shipboard gust alleviation.