Recent Advancements in Rotary Shape Memory Alloy Actuators for Aeronautics

A review of recent shape memory alloy (SMA) aeronautical applications is highlighted. To date, SMAs have not been successfully employed in critical aircraft actuation due to several technological and infrastructure challenges. Albeit fully functional SMA prototypes were demonstrated in aerospace environments over a decade ago, other critical elements such as material form, certification, and other crucial design tools have not progressed with the same level of maturity. The applications presented here have acknowledged these shortcomings and are built on previous successes to thrust SMAs a step closer to aircraft adoption. The spanwise adaptive wing (SAW) project and the wind tunnel remote control actuation (RCA) are the new applications that employ new advancement. First, the SAW project is the first ever, fully integrated flight test employing high-temperature SMAs with flight-relevant properties. The project utilized NiTiHf alloys with suitable actuation temperatures, and scalable to commercially available lots/forms. Second, the RCA project represents the next paradigm shift in wind tunnel testing. This application employs NiTi torque tubes capable of moving and controlling the model parts, enabling increased productivity, improved data quality, and reduced cost of wind tunnel testing. An overview of each application is provided here, with insights into system-level successes, challenges, and lessons learned.