초록 ▼

An aircraft comprises a wing (2) defining an aerofoil surface, the wing (2) comprising a drooped leading edge flap (1) being moveable between a stowed position and a deployed position. The wing (2) is so arranged that during flight when the high-lift device is in the deployed position, air may flow

An aircraft comprises a wing (2) defining an aerofoil surface, the wing (2) comprising a drooped leading edge flap (1) being moveable between a stowed position and a deployed position. The wing (2) is so arranged that during flight when the high-lift device is in the deployed position, air may flow through an opening (7) in the wing (2) and over the aerofoil surface. During flight, air preferably flows into the boundary layer (13) on the upper surface of the wing (2). This energises the boundary layer (13), aft of the trailing edge of the drooped leading edge flap increasing its stability allowing the maximum achievable lift coefficient to be increased and hence reducing aircraft take-off and approach speeds.

대표청구항 ▼

1. An aircraft comprising: a wing defining an aerofoil surface, wherein the wing comprises a main wing portion and a drooped leading edge flap, said main wing portion comprising an leading edge surface that extends from a leading edge chordwise distal point to an end point located on an upper surfac

1. An aircraft comprising: a wing defining an aerofoil surface, wherein the wing comprises a main wing portion and a drooped leading edge flap, said main wing portion comprising an leading edge surface that extends from a leading edge chordwise distal point to an end point located on an upper surface of said main wing portion, the drooped leading edge flap being configured to rotate, around an axis of rotation, between a stowed position and a deployed position, and wherein the wing, at least during certain flight conditions, when the drooped leading edge flap is in the deployed position, is formed with at least one opening which is defined by(a) an upper gap formed between and immediately adjacent to a rear surface of said drooped leading edge flap and at least part of said leading edge surface of said main wing portion,(b) a lower gap formed between and immediately adjacent to a lower trailing edge of said drooped leading edge flap and a lower surface of said main wing portion,(c) a cavity defined in said deployed position between the drooped leading edge flap and the main wing portion,wherein the drooped leading edge flap is configured such that, during certain flight conditions, when the drooped leading edge flap is in its deployed position, aerodynamic loads cause, at least in part, to vary the size of the upper gap, andwhereby during said certain flight conditions, i) air flows into the cavity through the lower gap, and ii) air flows out from the cavity through the upper gap and is mixed into the air of a boundary layer on the upper surface of the wing, thereby energizing the boundary layer and reducing it's susceptibility to separation from the aerofoil surface. 2. An aircraft according to claim 1, wherein the cavity has a cavity entry at a spanwise end of the drooped leading edge flap configured to allow air to flow into the cavity. 3. An aircraft according to claim 2, wherein the shape of the upper gap is such that the flow of air, per unit length in the spanwise direction, through a first region of the upper gap is greater than the flow of air, per unit length in the spanwise direction, through a second region of the upper gap. 4. An aircraft according to claim 2, wherein the aircraft is so arranged that, at least during certain flight conditions when the drooped leading edge flap is in the deployed position, the air flow, in the space between the drooped leading edge flap and the adjacent portion, at the region at the spanwise end of the drooped leading edge flap includes a spanwise component as a result of the direction of the flow of air drawn at said region. 5. An aircraft according to claim 1, wherein the wing is so arranged that at least some of the air that flows through the cavity is drawn from a region on the lower surface of the wing. 6. An aircraft according to claim 1, wherein the wing is so arranged that the flow of air through the cavity is driven by pressure gradients, said pressure gradients being formed as a result of the pressure distribution around the wing. 7. An aircraft according to claim 1 so arranged that, when the drooped leading edge flap is in the stowed position, the upper gap is closed. 8. An aircraft according to claim 1, wherein said drooped leading edge flap further comprises an axis of rotation, and wherein said axis of rotation coincides with the main wing portion. 9. An aircraft according to claim 1, the drooped leading edge flap further comprising a turning vane, wherein said turning vane is arranged to direct flow having a component of flow in the wing root-to-tip direction, so as to reduce the component of flow in the wing root-to-tip direction. 10. A drooped leading edge flap suitable for use as the drooped leading edge flaps of the aircraft according to claim 1. 11. A kit of parts including a drooped leading edge flap, the parts being suitable for converting an aircraft into an aircraft according to claim 1. 12. An aircraft according to claim 1, wherein the air drawn in from the region at the spanwise end flows along the wing in a spanwise direction. 13. A drooped leading edge flap suitable for use as the drooped leading edge flaps of the aircraft according to claim 1. 14. A kit of parts including a drooped leading edge flap, the parts being suitable for converting an aircraft into an aircraft according to claim 1. 15. The aircraft of claim 1, wherein said rear surface of said drooped leading edge flap is contoured to follow at least a part of said leading edge surface of said main wing portion when said drooped leading edge flap rotates between a stowed position and a deployed position. 16. An aircraft according to claim 1, the wing further comprising a plurality of vortex generators arranged such that, during flight when the drooped leading edge flap is in the deployed position, air flows past the vortex generators and vortices are introduced into the air flow. 17. An aircraft according to claim 16, wherein the vortex generators are shielded from any air flow when the drooped leading edge flap is in the stowed position. 18. An aircraft according to claim 1, wherein a size of the upper gap at a first region of the cavity is substantially larger than the size of the upper gap at a second region. 19. An aircraft according to claim 18, wherein the first region corresponds to a region near an engine nacelle, and the second region corresponds to a region away from the engine nacelle. 20. A method of operating an aircraft, wherein the method comprises the following steps: providing an aircraft (10) having a wing (12) defining an aerofoil surface, the wing having a wing tip (18), a main wing portion comprising a leading edge surface (68) that extends from a leading edge chordwise distal point (70) to an end point (at 64) located on an upper surface (64) of the main wing portion, and a drooped leading edge flap (20) configured to rotate, around an axis (80) of rotation, movable between a stowed position (FIG. 2) and a deployed position (FIG. 4), and flying the aircraft (Column 3, Lines 50-51), moving the drooped leading edge flap to the deployed position (Column 4, Line 1), and an upper trailing edge (44) and a lower trailing edge (48) of the drooped leading edge flap being immediately adjacent to the main wing portion (12, 70) to define (a) an upper gap (34) formed between and immediately adjacent to a rear surface (rear of 40 and 52) of said drooped leading edge flap and at least part of said leading edge surface (64) of said main wing portion (12), (b) a lower gap (98) formed between and immediately adjacent to a lower trailing edge (48) of said drooped leading edge flap and a lower surface (72) of said main wing portion, and (c) a cavity (96) between the drooped leading edge flap (20) and the main wing portion (14), wherein the drooped leading edge flap is configured such that, during certain flight conditions, when the drooped leading edge flap is in its deployed position, aerodynamic loads cause, at least in part, to vary the size of the upper gap, andwhereby air is caused to: i) flow into the cavity through the lower gap, and ii) air flows out from the cavity through the upper gap and is mixed into the air of a boundary layer (near the top of arrow 36) on the upper surface of the wing (64), thereby energizing (any additional airflow will add energy to the boundary layer) the boundary layer and reducing it's susceptibility to separation from the aerofoil surface. 21. A method according to claim 20, further comprising the step of providing a cavity entry at a spanwise end of said drooped leading edge flap, and wherein the flow of air through the cavity is driven by pressure gradients formed as a result of the pressure distribution around the wing. 22. A method according to claim 21, wherein the drawing of the air from the region at the spanwise end of the drooped leading edge flap causes spanwise flow of air along the wing between the deployed drooped leading edge flap and the adjacent portion of the wing. 23. A method of according to claim 20, wherein when the drooped leading edge flap is moved to the deployed position, a space is defined between the drooped leading edge flap and the main wing portion, the space having a spanwise end, air passes into the space from the spanwise end of the space, flows in a spanwise direction along the space towards the wing tip, and flows from the space into a boundary layer on the upper surface of the wing. 24. A method according to claim 23, wherein air is also drawn into the space from the lower surface of the wing.