Covert-Inspired Flaps as Flight Control Surfaces for BWB aircrafts

Recently, there has been renewed interest in Blended Wing Body (BWB) aircraft because they provide reduced drag, larger lifting surfaces, and increased cargo volume compared to conventional configuration airplanes. However, the lack of a separate empennage section reduces the overall control authority available for stability and agility and complicates the flight control laws. In this paper, we present a novel control effector inspired by a feather system in birds known as the covert. The authors have previously investigated the effect of covert-inspired flaps on a two-dimensional wing section and show that the bioinspired flaps can result in 1.5 times more effective yaw control than a conventional collocated flap surface. In this presentation, we will extend the previous results to a three-dimensional wing section to investigate the effect of the covert-inspired flaps on the flow field and its resulting roll, pitch, and yaw control authority when it is deflected asymmetrically on the right and left wings. More specifically, we present results from wind tunnel experiments in Princeton University's low turbulence wind tunnel, where we systematically vary the flap location and deflection angles. Moreover, we will vary the flow angles (i.e., the angle of attack and side slip angle) and their rates to represent different flight maneuvers. Results will include flow field measurements from time-resolved PIV, force measurements, and data-driven models that relate the measured aerodynamic forces to the flap and flow parameters.