Influence of control surfaces deflection on longitudinal aerodynamic characteristics of a tailless unmanned aerial vehicle

Influence of control surfaces deflection on longitudinal aerodynamic characteristics of a tailless unmanned aerial vehicle (UAV) with multiple control surfaces was investigated in a wind tunnel using force measurement. Positive deflection of both elevons and flaperons leads to an increment of lift coefficient, drag coefficient and nose-down pitching moment, and the increment is much more significant with a larger deflection angle. Elevons have a better effect than flaperons. However, all-moving tips (AMTs) deflection nearly has no influence on longitudinal aerodynamic characteristics. When deflecting canard wings, lift coefficient and drag coefficient nearly have no changes before stall, while they are reduced after stall. When α<16° and α>38°, positive deflection of canard wings reduces the nose-down pitching moment, and negative deflection increases the nose-down pitching moment. The order of pitching moment control efficiency from higher to lower is: elevons, flaperons, canard wings, AMTs. Further analysis indicates that the control efficiency is related to the control surface volume coefficient.