The Analysis of Lateral Stability of Tailless Camar-3 With Winglets

Abstract

This paper analyses the lateral stability of tailless CAMAR-3 Unmanned Aerial Vehicle (UAV) when its tail fin (i.e. V-tail) is reconfigured to the wingtips. A tailless UAV may have longer endurance time, compared to the present configuration of V-tail. Nevertheless, a tailless UAV may experience reduction in lateral stability due to loss of yaw control surfaces. In the preliminary design of tailless-winglets UAV, semi-empirical method is applied to estimate the aerodynamic lateral stability derivatives, in order to investigate the stability of both configurations of UAV. A dynamic test rig based on pure yawing motion is built, to measure the lateral stability derivatives of  and  The time response data of pure yawing oscillation give the natural frequency and damping ratio that describe the aerodynamic derivatives as a result from wind-on and wind-off tunnel tests. The result indicates that UAV with either configurations are laterally stable. However, the tailless-winglets CAMAR has a 13.86% reduction in aerodynamic yawing-moment-due-to-sideslip derivative , compared to  CAMAR-3 with V-tail, whereas the aerodynamic yawing-moment-due-to-yaw-rate derivative  of tailless-winglets CAMAR is 5.55% lesser thanthat of the CAMAR-3 with V-tail. The lateral stability degrades, as expected, caused by tail stabilizer removal. In conclusion, the idea of tail removal and using winglets as the directional controllers is feasible.