Enhanced energy maneuverability for attack helicopters using continuous, variable rotor speed control

Abstract

The results of this research indicate that continuous, variable rotor speed control is a viable solution to increased helicopter maneuverability and agility. Of the rotor speed control laws investigated, the RCDR and T (RC) types seem the most promising. In particular, these control laws demonstrated a 31% improvement in time-to-turn 180 degrees, a 38% improvement in turn penetration distance, a 42% improvement in turn cross track distance, and a pointing margin advantage of nearly 94 degrees. In addition, the rotor speed control law parameters could be optimized such that the helicopter exited a maximum performance decelerating turn at or above its power bucket speed, affording the helicopter a distinct maneuvering advantage. It was also shown that different rotor speed control laws would most likely be required for the air combat and ground attack mission scenarios. The author feels that successful variable rotor speed control can be achieved through an appropriate marriage of FADEC engine control and high performance flight control systems. But numerous questions remain relative to the successful integration of this technology to existing and/or future helicopter designs, (addressed in the Recommendations for Future Research section). Nevertheless, this technology shows considerable promise and it is hoped that this study will be a stepping stone to future investigations in this area.