SMA Active Rotor Trim Tab

Midé proposes to build an on-blade active trim tab using Shape Memory Alloys. SMAs are active materials that undergo a phase change from martensitic to austenitic form when heated. The materials can be trained to a specific shape in the austenitic phase. When heated, the material will recover the trained shape. Since the modulus in the austenitic phase is relatively high, the force exerted is large. The specific energy in the device is very high, and the form factor is small, since the actuator consists in essence of a wire bundle. The proposed actuator is a self-locking device so that no power is required to hold a trim tab set point, and the failure modes are benign. A fixed-frame control system is used to set tab position, so that the system requires no fixed/rotating frame data transfer.