Low Reynolds Number Experimental Tests of an Eppler-186 Airfoil With Gurney Flap for Small-UAV

An experimental wind tunnel study is performed on an EPPLER-186 airfoil equipped with a Gurney flap. The main goal is to improve the lift coefficient and lift-to-drag ratio of a small Unmanned Aerial Vehicle (UAV) during different flight conditions. This way, the vehicles would perform better aerodynamics, reducing take-off and landing distances. The aerodynamic forces are obtained using an external balance to quantify the effect on the flow with the various sizes of Gurney flaps installed. Adding the device at the trailing edge significantly increases lift values at low angles of attack (up to +0.32 points in lift coefficient). Drag values also increase, but for cruise flight at low angles of attack aerodynamic efficiency increases up to +6 points with respect to the base wing without Gurney flaps.