Abstract: A flap mounted in a track member for movement between a retracted and an extended position. The track member itself is pivotally mounted at a forward portion thereof for up and down rotational movement. With the flap in its retracted position, upward and downward rotation of the track causes the flap to move to upper and lower cambered positions. The flap member in its extended position forms a slot with the wing, and upward and downward rotational movement of the track changes the deflection angle of the flap member to provide greater or less lift, to optimize the wings for various cruise conditions, to alleviate gust loads and provide improved maneuverability.