A gurney flap assembly has an actuator, a flexible or hinged body, the body flexing from a retracted to a deployed position in reaction to motion of the actuator, and a first seal extending along a first edge of the flexible body that flexes from the stowed position. Linear motion of the actuator output is transposed to the gurney flap thereby moving it from a retracted position into the airstream. This trailing edge device will improve airfoil lift.