CAREFREE MANOEUVRING IN HELICOPTER FLIGHT CONTROL

Carefree manoeuvring represents the ability of a pilot to fly throughout the operational flight envelope without concern for exceeding structural, aerodynamic or control limits. Such an attribute is difficult to achieve with conventional design, but can be realized through active flight control. In this context, this paper describes a ground-based piloted simulation study of a novel carefree manoeuvring control law designed to balance the conflicting requirements of stability, control, handling qualities and limit protection. The key to achieving this balance in the heave axis is an adaptive flight control system mode which blends between collective blade pitch command, torque command and rotorspeed command as a function of collective position. This allows the pilot to command the full range of available performance up to, and including, the maximum transient limits in a safe and predictable manner. The results of the simulation study have shown that control modes designed specifically to protect flight envelope limits can (i) improve limit protection in high aggression, large amplitude manoeuvres, (ii) reduce task time in such manoeuvres by allowing the pilot to command maximum available performance, and (iii) reduce workload and improve situational awareness by relieving the pilot of the need to monitor cockpit instruments. Achieving carefree manoeuvring in future military helicopters therefore offers potential for enhanced combat capability and hence mission effectiveness.