Characterization of a Rotary Flat Tail as a Spoiler and Parametric Analysis of Improving Directional Stability in a Portable Uav

The United States Air Force Research Lab, Munitions Directorate, Flight Vehicles, Integration Branch (AFRL/MNAV), has developed a flexible wing micro air vehicle (MAV) to be used with special tactics groups. In keeping with the requirement that this MAV be compact, previous research developed a rotatable tail mechanism which resulted in tail movement similar to that of a bird's tail. In this study the design of this tail was modified to produce a more storable vehicle. The redesign also allowed the tail to deflect upward to large angles, enabling the tail to be used as a spoiler. The aerodynamic affects of adding a vertical stabilizer mechanism to improve the stability of the vehicle and rotatable tail combination was also quantified. Data from these tests confirmed the tail is a plausible method to reduce lift and increase drag, consistent with proper spoiler function. A wide range of angles were used to demonstrate that forces and moments from the flat tail were similar to those of traditional rudder. Directional stability was improved by the stabilizer, and recommendations for further improvements are given.