High-lift device for an aircraft
AssigneeAirbus UK Limited
InventorsIan Roy Whitehouse, Edmund Kay, Daniel Dodd
Life of this patent
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Abstract
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.
Claims24
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, and
- whereby 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.
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, and
- whereby 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.
Dependencies are inferred from the claim text.