Aircraft Dynamic Load Alleviation Using Smart Actuation System

Abstract : This report was developed under SBIR contract for topic AF99-28O describes an analytical development of buffet and gust load alleviation methodology. An active control surface modal device is employed to generate out-of-phase aerodynamic damping that reduces dynamic loads arising from buffet and gust encounter. Lightweight smart actuators having high response rate are used to activate the control surface modal device. This concept can also be applied to flutter suppression of any lifting surfaces. This active control algorithm can be implemented and operated independently of the primary flight control systems to avoid interference. The test cases include buffeting of F-18 twin vertical tails in high alpha flight configuration and gust environment. Analytical predictions show 80 percent reduction in tail root stress that could result in eight fold increase in fatigue life of an aircraft. Consequently, if this dynamic load alleviation methodology is implemented into existing and new military aircraft several millions of dollars can be saved per aircraft in its service life.