Influence of Gurney flap on longitudinal aerodynamic characteristics of  multiple-control-surface UAV

An experiment had been conducted to investigation the effect of different control surfaces with Gurney flaps on the aerodynamic characteristic of a multiple-control-surface tailless aircraft model. It is found that either the individual elevons and flaperons, or their combinations with Gurney flaps can increase the lift coefficient, while the drag and nose-down pitching moment coefficients are also enhanced inevitably. In contrast, when the canard wing is equipped with Gurney flaps, the lift and drag coefficients have nearly no change at the linear stage, while the nose-down pitching moment coefficients decrease significantly during the angles of attack tested. Therefore, the combinations of the canard wing and either the elevons or flaperons with Gurney flaps were further tested. The results show that such combinations can increase the lift coefficient while keep the pitching moment coefficient almost unchanged, which is benefit to improve the aerodynamic performance of aircraft.