Lifting surface of an aircraft for increasing the generated lift force

Abstract

A lifting surface of an aircraft, comprising a leading edge and a notch located in the leading edge. The notch comprises two walls adapted to be parallel to the direction of the incident flow to the lifting surface and a third wall adapted to face the incident flow to the lifting surface when it is in flight. The lifting surface also comprises a retractable cover element, the notch and the retractable cover element being configured such that when the retractable cover element does not cover the notch, the notch is exposed to the incident flow generating a vortex which increases the lift force of the lifting surface, delaying stall.

Claims

1. A lifting surface of an aircraft, comprising: a leading edge and a notch located in said leading edge, the notch comprising two walls adapted to be parallel to the direction of the incident flow to the lifting surface and a third wall adapted to face the incident flow to the lifting surface when it is in flight, the lifting surface also comprising a retractable cover element, the notch and the retractable cover element being configured such that when the retractable cover element does not cover the notch, said notch is exposed to the incident flow generating a vortex which increases the lift force of the lifting surface, delaying stall, wherein the retractable cover element is retracted toward the tip of the lifting surface and is placed above the leading edge of the lifting surface when retracted.

2. The lifting surface of an aircraft, according to claim 1, wherein the lifting surface is a horizontal stabilizer.

3. The lifting surface of an aircraft, according to claim 1, wherein the cross-section of the retractable cover element follows the shape of the cross-section of the leading edge.

4. The lifting surface of an aircraft, according to claim 1, wherein the third wall of the notch comprises a streamlined shape.

5. The lifting surface of an aircraft, according to claim 1, wherein said notch does not extend beyond a front spar of the horizontal stabilizer.

6. The lifting surface of an aircraft, according to claim 1, further comprising an actuation mechanism for retracting said retractable cover element.

7. The lifting surface of an aircraft, according to claim 1, wherein the aspect ratio chord/span of the notch is greater than 1.

8. An aircraft comprising the lifting surface according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) To complete the description and in order to provide for a better understanding of the invention, a set of drawings is provided. The drawings form an integral part of the description and illustrate preferred embodiments of the invention. The drawings comprise the following figures.

(2) FIG. 1 shows a schematic representation of a lifting surface of an aircraft having a notch in the leading edge and the incident flow into the leading edge.

(3) FIG. 2 shows a schematic representation of a lifting surface of an aircraft having a notch in the leading edge.

(4) FIG. 3 shows a schematic representation of a lifting surface in an aircraft having a notch in the leading edge.

(5) FIG. 4 shows a schematic representation of an embodiment of the leading-edge device object of the invention.

(6) FIG. 5 shows a schematic representation of a lifting surface of an aircraft having a notch in the leading edge together with its aspect ratio.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

(7) FIGS. 1 and 2 disclose a schematic representation of an embodiment of the leading edge (2) object of the invention. As it is shown, the notch (3) comprises three walls, two walls (6) parallel to incident flow and a third wall (5) facing the incident flow. The retractable jacket (4) is movable along the leading edge (2) when additional lift is needed. During cruise the retractable jacket (4) covers the notch (3) in default configuration to minimize drag.

(8) The characteristic lengths of the notch (3) are chord (c) and span (b). The dimensions of the characteristic lengths must provide an aspect ratio c/b greater than 1 as can be seen in FIG. 5.

(9) More particularly, the cross-section of the retractable jacket (4) follows the shape of the cross-section of the leading edge (2) and therefore allows covering the notch (3) without modifying the leading edge (2) profile when the retractable jacket (4) covers the notch (3). That is, the aeroshape of the jacket (4) which is the element of leading edge that slides is not modified with respect to the conventional airfoil section.

(10) In the disclosed embodiment, the chord length of the notch (3) is smaller than the leading edge chord and extending up to a distance which guarantees the structural integrity of the front spar of the lifting surface (1) in the event of damage (bird strike, service vehicles, FOD, . . . ).

(11) In the disclosed embodiment, the retractable jacket (4) is movable along the leading edge (2) in the spanwise direction. The thickness of the lifting surface (1) increases towards its root (11), therefore, if the retractable jacket (4) is located between the root (11) of the lifting surface (1) and the notch (3) when it is not covering the notch (3), then it is stowed inside the leading edge (2) of the lifting surface (1), i.e., under the skin of the leading edge (2). Conversely, if the retractable jacket (4) is located between the notch (3) and the tip (10) of the lifting surface (1) when it is not covering the notch (3), then it is stowed over the leading edge (2) of the lifting surface (1), i.e., covering the skin of the leading edge (2).

(12) The lifting surface (1) also comprises an actuation mechanism for retracting the jacket (4) upon command, for instance, a spring-loaded actuator.

(13) The internal exposed third wall (5) of the notch (3) facing the incoming flow ought to be streamlined in order to minimize a drag penalty at low angles of attack. This could be achieved by streamlining the third wall (5) toward a shape that replicates a secondary leading edge exposed only when the retractable jacket (4) is retracted/stowed.

(14) While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms comprise or comprising do not exclude other elements or steps, the terms a or one do not exclude a plural number, and the term or means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.