REINFORCED LEADING EDGE SECTION FOR AN AIRCRAFT

Description

Object of the invention

[0001] The present invention refers to a leading edge configuration for an aircraft.

[0002] An object of the present invention is to provide a leading edge section for an aircraft that minimizes the weight and cost required in its manufacturing, at the same time that withstands a bird strike event.

[0003] Another object of the present invention is to provide a leading edge section for an aircraft that is compatible with any manufacturing material.Background of the invention

[0004] Bird strike collisions during flight, take-off and landing happen every day, jeopardizing people and aircraft integrity.

[0005] Certification regulations governing certain categories of aircraft require that, in the event of damage to a component caused by collision with a bird, the aircraft has to be capable of maintaining flight long enough to reach a landing site. For that, conventional aircraft lifting surfaces are configured to both withstand the bird strikes and fulfilling the aerodynamic requirements. The integration of these both functionalities results in a secured, but heavy design of the leading edges of the aircraft that ensure that the not affectation of the primary structure allocated behind said leading edges.

[0006] Nowadays, aircraft aerodynamic surfaces, such as wings or stabilizers (a Horizontal Tail Plane (HTP) or a Vertical Tail Plane (VTP)), comprises leading edges with increasing thickness in order to reach the maximum value in their outermost parts (the so-called D nose), which is the critical area from the impact point of view.

[0007] Figure 1 shows a state of the art aircraft aerodynamic surface 5 having a leading edge 6, a trailing edge 7 and several spars 8 in-between. As shown, the leading edge 6 comprises several composite plies 9 laid up to engross the leading edge 6 area, resulting in a heavy part.

[0008] Therefore, it would be desirable to provide a new leading edge that reduces the weight and cost of traditional leading edge sections.

[0009] Document WO 2005 / 030577 A1 discloses a protective skin for an aircraft is disclosed. The protective skin forms the leading edges of wing members, horizontal stabilizers, and vertical fins. A portion of the skin material is removed in a selected pattern from the interior surface of the skin. In an embodiment, the interior surface of the skin is chemically etched and / or mechanically milled in oval and rectangular patterns so as to create crumple zones and generate progressive failure of the metal. This allows the leading edge to absorb the impact energy from a collision with a bird or other object, and prevent the bird or other object from penetrating through the leading edge into the substructure.

[0010] Document EP 2687436 A1 discloses a method for manufacturing a leading edge profile section of an aircraft lifting surface. Also, this document discloses a leading edge profile section manufactured by said method comprising in addition to the skin of the leading edge profile section, one or more of the following structural elements: an auxiliary spar, a longitudinal stiffener reinforcing an auxiliary spar, a longitudinal stringer reinforcing the skin of the leading edge profile.Summary of the invention

[0011] The present invention overcomes the above mentioned drawbacks by providing a leading edge section for an aircraft with a reduction in weight and cost.

[0012] The present invention refers to a reinforced leading edge section as defined in claim 1.

[0013] This way, the invention provides a new section with a more resistive structure (mass) incorporated in the forward area of the leading edge, resulting in a section capable of absorbing more energy from a bird impact.

[0014] The new leading edge section offers a part with reduced weight and manufacturing cost due to the simplification of the design. The thickness changes in the leading edge will be avoided by adding an inner reinforcement along the D nose forward area. In addition, this configuration increases the inertia for the critical impact direction, adding the reinforcement just in the most important area.Brief description of the drawings

[0015] For a better comprehension of the invention, the following drawings are provided for illustrative and non-limiting purposes, wherein: Figure 1 shows a schematic view of a state of the art leading edge provided with a thickening in its outermost area. Figure 2 shows a schematic view of a leading edge section, according to an example not part of the present invention. Figure 3 shows a schematic view of a leading edge section, according to a second embodiment of the present invention. Figure 4 shows an aircraft equipped with the leading edge section of the invention. Preferred embodiments of the invention

[0016] Figure 2 shows a reinforced leading edge section (1) for an aircraft that comprises an outer skin (2) and an inner reinforcement (3). The outer skin (2) is formed with an aerodynamic leading edge profile. The inner reinforcement (3) is arranged internally with respect to the outer skin (2) along the span of the leading edge section (1).

[0017] As shown in Figure 2, the inner reinforcement (3) comprises a base (3'), and a web (3") with a free end (3"a) and an opposite end (3"b) joined to the base (3'). The base (3') has a C-shaped configuration and it is joined to the outermost part of the outer skin (2). The web (3") is extended in a direction transverse to the direction of the span of the leading edge section (1).

[0018] This way, this example provides a leading edge section with an improved impact behavior, a reduced weight, and easier manufacture due to the avoidance of thickness changes.

[0019] As shown in Figure 3 and according to the invention, the reinforced leading edge section (1) further comprises one pair of secondary reinforcements (4) attached to both ends of the base (3') of the inner reinforcement (3) to maximize the forward mass. As shown, the secondary reinforcements (4) are preferably radially extended towards the free end of the web (3"a).

[0020] As in Figure 2, the web (3") of the inner reinforcement (3) is extended towards the rear part, the leaving a marginal distance to avoid any contact of the inner reinforcement (3) with the front spar (8) in the event of a bird strike.

[0021] According to another preferred embodiment, the thickness and / or height of the inner reinforcement (3) is at least twice the radius of the leading edge section (1).

[0022] According to another preferred embodiment, the thickness of the base (3') of the inner reinforcement (3) is different from the thickness of the web (3") in order to optimize the construction of the part.

[0023] According to another preferred embodiment, the inner reinforcement (3) is made of metallic or composite material.

[0024] According to another preferred embodiment, the inner reinforcement (3) is attached to the outer skin (2) by riveting or welding when the leading edge section (1) is metallic, or by riveting, cobonding, or cocuring when the leading edge section (1) is of composite material.

[0025] Finally, Figure 4 shows an aircraft 10 equipped with the leading edge section (1) as described in the wings, the HTPs and the VTP.

Claims

1. A reinforced leading edge section (1) for an aircraft, comprising: - an outer skin (2) formed with an aerodynamic leading edge profile, and - an inner reinforcement (3) arranged internally with respect to the outer skin (2) along the span of the leading edge section (1), wherein said inner reinforcement (3) comprises a base (3') with a C-shaped configuration joined to the outermost part of the outer skin (2), and a web (3") having a free end (3"a) and an opposite end (3"b) joined to the base (3'), the web (3") extended in a direction transverse to the direction of the span of the leading edge section (1); and characterized in that the reinforced leading edge section (1) further comprises at least one pair of secondary reinforcements (4) attached to both ends of the base (3') of the inner reinforcement (3).

2. A reinforced leading edge section (1) for an aircraft, according to claim 1, wherein the secondary reinforcements (4) are radially extended towards the free end of the web (3"a).

3. A reinforced leading edge section (1) for an aircraft, according to any of the preceding claims, wherein the thickness and / or height of the inner reinforcement (3) is at least twice the radius of the leading edge section (1).

4. A reinforced leading edge section (1) for an aircraft, according to any of the preceding claims, wherein the thickness of the base (3') of the inner reinforcement (3) is different from the thickness of the web (3").

5. A reinforced leading edge section (1) for an aircraft, according to any of the preceding claims, wherein the inner reinforcement (3) is made of metallic or composite material.

6. A reinforced leading edge section (1) for an aircraft, according to any of the preceding claims, wherein the inner reinforcement (3) is attached to the outer skin (2) by riveting or welding when the leading edge section (1) is metallic, or by riveting, cobonding, or cocuring when the leading edge section (1) is of composite material.