Slotted wing flaps for a VTOL aircraft
Devices and systems of the inventive concept provide an aircraft flap system is deflected to achieve minimum drag in cruise, maximum coefficient of lift (CL) at low speed, and minimum download in hover. It does so by opening a gap or slot between an aircraft's wing body and an associated trailing flap during hover flight, while providing a continuous aerodynamic contour under other conditions.
1. A method of operating a vertical takeoff and landing (VTOL) aircraft,
wherein the VTOL aircraft comprises a wing, wherein the wing comprises 1) a wing body having an upper and a lower surface and comprising a leading edge and a trailing edge, wherein the trailing edge comprises a channel, 2) a trailing flap, and 3) an intermediate body interposed between the wing body and the trailing flap;
the method comprising:
maintaining the intermediate body within the channel when the trailing flap is in a stowed position;
extending the intermediate body and trailing flap away from the channel and at least 75° downward relative to the wing body, so that the aircraft wing is in a hover position when the aircraft is in a hover flight condition; and
forming a vertical gap between the wing body and the intermediate body, wherein the entire intermediate body is below the entire wing body; and wherein the vertical gap is sufficiently large to provide a break in the aerodynamic contour represented by the wing body and the trailing flap when the aircraft wing is in the hover position.
2. The method of claim 1 , wherein the wing body and the trailing flap describe an angle of 35°-45° when the aircraft wing is in a high lift position.
3. The method of claim 1 , wherein the wing body, the intermediate body, and the trailing flap provide a continuous aerodynamic contour when the aircraft wing is in zero deflection.
4. The method of claim 1 , wherein the aircraft wing and the trailing flap describe an angle of 75°-95° when the aircraft wing is in the hover position.
5. The method of claim 1 , wherein the intermediate body juxtaposes the trailing flap when the aircraft wing is in the hover position.
6. The method of claim 1 , wherein an angular relationship between the intermediate body and the trailing wing is maintained between the stowed position and the hover position.
7. The method of claim 1 , wherein the intermediate body retains a fixed position with respect to the trailing flap in both the stowed and hover positions.
8. The method of claim 1 , wherein a top of the intermediate body is below an edge of the wing body when the aircraft wing is in the hover position.
9. The method of claim 1 , wherein the vertical gap is at least as wide as a length of the intermediate body.