Examination of Rotor Loads due to On-Blade Active Controls for Performance Enhancement

On-blade active controls with trailing-edge deflection, leading-edge deflection, and active-twist are studied for improvements in rotor aerodynamic efficiency and their influence on structural loads. A full-scale UH-60A Blackhawk rotor at two key flight conditions (high-speed forward flight and high-thrust forward flight) is studied using coupled computational fluid dynamics and computational structural dynamics simulations. A simulationbased trade study is carried out comprising parametric variations of geometric sizing and deployment schedules of the blade morphing. The study shows that active controls improve rotor performance and reduce rotor loads at the sametimewithcarefulselectionofdeploymentscheduleanddesign.Inhigh-speedforward flight,usingtrailing-edge deflection, an improvement of 7.3% in performance and a reduction in the hub vibratory loads of up to 54% is achieved,and using active-twist animprovement of 7.0% in performance and upto 22% reduction in hub vibratory loads is achieved. In high-thrust forward flight, a 15.0% improvement in performance and up to 40% reduction in hub vibratory loads is achieved using leading-edge deflection.