WO2018211128A1

WO2018211128A1 - Method for manufacturing elements that protect the leading edge of a wing, protective element obtained using the method and assembly of such protective elements

Info

Publication number: WO2018211128A1
Application number: PCT/EP2018/063230
Authority: WO
Inventors: Christophe BECHERT
Original assignee: J.P.J.
Priority date: 2017-05-19
Filing date: 2018-05-18
Publication date: 2018-11-22
Also published as: FR3066529B1; FR3066529A1

Abstract

The invention relates to a method for manufacturing protective elements (7) for application to the exterior surface of the region of the leading edge of a wing (A) in order to protect same, said region having a variable radius of curvature such that said exterior surface is formed of at least one developable ruled surface. The method comprises a step in which, on the basis of a three-dimensional computer model of the exterior surface, the or each developable ruled surface is developed, a step in which generatrices of the developable ruled surface or surfaces is or are determined, and a step in which, for each developable ruled surface, slots (7c) are made in at least one block of sheet type, the slots each extending along a straight line which coincides with a straight-line segment defined by one of the generatrices. The invention relates to a protective element (7) obtained by this method and to an assembly of such protective elements (7).

Description

METHOD OF MANUFACTURING WING ATTACK EDGE PROTECTION ELEMENTS, PROTECTIVE ELEMENT OBTAINED BY THE METHOD AND SET OF SUCH PROTECTIVE ELEMENTS

The present invention relates to the field of aeronautical maintenance and relates, in particular, to a method of manufacturing protection elements of a leading edge of a wing of an aircraft when it is immobilized on the ground, and a protection element obtained by this method and a set of these protective elements intended to cover the entire leading edge of a wing.

When maintenance operations must be performed on an aircraft, preventing it from flying, the aircraft is generally driven into a hangar where maintenance operations will be performed.

In this hangar, many vehicles, tools and aircraft parts are moved by maintenance operators. These numerous displacements occur near the plane, and in particular the leading edge of the wings which is particularly exposed. However, the leading edge is an essential part of the aircraft and the slightest defect can compromise the behavior of the aircraft in flight. It is therefore essential to have a protective element on the leading edge to prevent shocks from damaging it.

It is known to protect the leading edge by foil or plate-like protective elements, which are placed next to one another and against the leading edge and the region in the vicinity thereof, designated hereinafter "leading edge region" so as to completely cover it. Protection elements are held in position, for example by straps surrounding the wing, fastening systems loops and hooks (Velcro® type), by bungees, etc.

Each protection element is manufactured by cutting, wire or machining, in a block of solid foam, in a profile substantially corresponding to the average profile of the leading edge region that the protective element in question is intended to cover , over a length of about 200 to 400 mm depending on the degree of variation of the profile in the leading edge region considered.

The different elements are then glued end to end, then the inner faces, namely that intended to come into contact with the wing, and external are covered with two thin skins, 3 to 10 mm thick, glued while being stretched , the skins for connecting between the different elements and thus to hide the details and the assembly defects.

It is therefore understood that such protection elements are adapted only to constant profile wing sections, which is rarely the case on an aircraft wing.

Thus, these protection elements have certain disadvantages when they are installed on a leading edge region of a wing having a variable profile. First, the shape of the elements does not allow them to marry the shape of the leading edge region, so that in case of shock, it will not be absorbed properly. In addition, such elements are expensive to manufacture, because there is a significant loss of material during the cutting of the solid blocks. Finally, their manufacture is long, because after cutting, it is then necessary to stick the skins, wait for the glue dries, etc. The present invention aims at solving the problems encountered with the conventional protection elements described above and at providing protection elements that closely match the leading edge region while being manufactured quickly and economically.

The present invention takes advantage of the fact that the outer surface of the leading edge region is (or can be approximated very closely by), with the exception of the root, either a developable controlled surface or can be broken down into a plurality of adjacent developable controlled surfaces in the wingspan direction, and that the geometry of the outer surface can thus be defined using generatrices extending generally in the span direction of the wing. At the root is usually a fillet.

According to the present invention, the above-mentioned objective is achieved by making slots in a sheet-like block, the slots being positioned such that when the protective member is applied against the surface of the edge region the slits each extend along a respective generator, which allows the protection element to be bent, without being damaged, to fit very closely the outer surface of the edge region. of attack.

The subject of the present invention is therefore a method for producing sheet-type protective elements intended to be applied to the outer surface of the region of a leading edge of an aircraft wing so as to protect said region. leading edge, the latter having a radius of curvature that varies from the end of the root wing at the free end of the wing, so that said outer surface is formed of at least one developable controlled surface, the method being characterized by comprising:

a surface development step, in which, from a three-dimensional computer model of the outer surface of said leading edge region, the or each developable controlled surface forming said outer surface is developed, so as to obtain a or more so-called developed surfaces;

a generator determining step, in which generatrices of the or each developable regulated surface are determined; and

a step of producing protection elements, in which, for the or each developable controlled surface, in at least one sheet-like block, slots are made which open onto the same surface of said at least one sheet-like block; each extending along a straight line coinciding with a defined line segment on the corresponding developed surface by one of the generators determined in the generator determining step.

Advantageously, prior to the step of producing protection elements, one or more developed surfaces are divided into a plurality of so-called elementary developed surfaces, the slots being made in a plurality of sheet-like blocks, with a sheet-like block for each developed surface. elementary.

Preferably, the slots are made with a pitch between slots which increases as one deviates from the center line of the sheet type block.

The slots can be made to have a depth of at least 50% of the thickness of the block leaf type, depth measured at the right of said slot. The thickness of the sheet-like block or blocks can for example be between 5 mm and 120 mm.

Preferably, the one or more sheet-like blocks in which the slits are made may be of polymeric foam, preferably polyethylene.

Preferably, in the step of producing protection elements, in a sheet-like block intended to be applied on the outer surface of the region of the leading edge which is at the end of the on the root side, at least one secondary slot which opens onto the surface of said sheet-like block into which said slots open, the at least one secondary slot extending along a straight line which is perpendicular to the center line of said sheet-like block; the at least one secondary slot being located in the edge region of said sheet-like block which will be at the root end.

The secondary slot or slits thus allow the protection element to be also slightly curved at its edge which is applied against the connection fillet connecting the wing to the fuselage of the aircraft, for further protection vis-à-vis the against shocks.

The present invention also relates to a sheet-like protective element intended to be applied to a portion of the outer surface of the region of a leading edge of an aircraft wing, characterized in that it is obtained by the method as defined above, so that it is in the form of a sheet-like block having slots which open onto the same surface of the sheet-like block and which each extend according to a line that coincides with a defined line segment on the developed surface corresponding to the portion of the outer surface of the leading edge region to be covered by the protection element, by one of the generators determined in the generator determining step.

Advantageously, the slots have a pitch between slots which increases as one deviates from the center line of the sheet-like block.

Preferably, the slots have a depth of at least 50% of the thickness of the sheet-like block, depth measured at the right of said slot. The thickness of the sheet-like block may for example be between 5 mm and 120 mm.

Preferably, the sheet-like block may be of polymeric foam, preferably polyethylene.

Preferably, for a protective member to be applied to the outer surface of the leading edge region at the end of the root side flange, the sheet-like block forming the present protective member at least one secondary slot which opens onto the surface of said sheet-like block into which said slots open, the at least one secondary slot extending along a straight line which is perpendicular to the center line of said sheet-like block and the at least one secondary slot being located in the edge region of said sheet-like block which will be at the root end.

The present invention also provides a set of sheet-like protective members for application to the outer surface of the leading edge region of an aircraft wing so as to protect said edge region. the protection elements being as defined above and thus obtained by a method as defined above, each protection element corresponding to a developable controlled surface or, where appropriate, to an elementary developed surface, so that the protection elements are able to be arranged end to end on the leading edge region and to cover it substantially on all its length.

To better illustrate the object of the present invention, will be described below, for information only and not limited to, a particular embodiment with reference to the accompanying drawing.

On this drawing :

- Figure 1 is a perspective view of a three-dimensional model, in a wired view, of the leading edge region of an aircraft wing;

FIG. 2 is a view of two developed surfaces, derived from the model of the leading edge region which has been developed and divided in two, in accordance with a step of the method according to the present invention, and on which generators appear and transverse segments;

Figure 3 is a view of the two developed surfaces of Figure 2, in which the transverse segments have been removed;

- Figure 4 is a view of a plurality of elementary developed surfaces from the two developed surfaces of Figure 3;

FIG. 5 is a perspective view of an aircraft wing and a portion (shown schematically) of the fuselage of the aircraft, the protective elements obtained. by the method according to the present invention being applied to the leading edge region modeled in Figure 1; and Fig. 6 is a cross-sectional view of a portion of the wing of Fig. 5, showing the leading edge region and a protective member 7 positioned thereon. Referring first to Figure 1, it can be seen that there is shown in perspective a three-dimensional computer model 1 of the outer surface of the leading edge region of a wing. left-side aircraft, by means of which the method of manufacturing protection elements according to the present invention will be described in more detail. Of course, the leading edge region modeled in FIG. 1 is only one example and the present invention is not limited to the specific geometry of this leading edge region. In addition, for the sake of brevity, the same reference numerals will denote the characteristics of the leading edge region and the modelizations thereof on the model 1.

Model 1 can be obtained by any appropriate means.

In general, the wings are modeled informally by computer-assisted design (CAD) software or computer-aided design (CAD) software, and it is easy to extract the model from the leading edge region. of the wing. It is however quite possible, while remaining within the scope of the present invention, to model the region of the leading edge of a wing by digitizing it using a scanning-type device (3D scanner / 3D camera) or performing measurements of the leading edge region geometry at a plurality of points thereof.

In the case of the model shown in Figure 1, the region of the leading edge is shown in wireframe view, that is to say that the surface is rendered using lines: here two types of lines, to namely generators G in the direction of the span of the wing and transverse segments T parallel to the longitudinal direction of the aircraft and thus in the direction of the flow of air around the wing. Such a representation is particularly easy in that the outer surface of the leading edge region is a developable controlled surface or can be divided, in the direction of the wingspan, into a plurality of developable tuneable surfaces.

It is recalled that a regulated surface is a surface through which each point passes a line, called a generator, contained in the surface, and that such a surface is said to be developable when the tangent plane is the same along such a generator. . In other words, one could "roll without dragging" the surface of the region of the leading edge on a plane, the contact being along a straight line called generator.

Thus, the computer model already contains the generators G of the developing one or more surfaces constituting the outer surface of the leading edge region.

Of course, in the case where generators G are not initially available, these can be determined conventionally by calculation, many CAD or CAD software offering the possibility of determining the generators of a developable controlled surface. In the exemplary leading edge region of which the model 1 is shown in FIG. 1, the leading edge region has a longitudinal directional change about 1/3 of its length from its end. root 2, and it can thus be divided into first and second developable adjustable surfaces defining two parts of the leading edge region: a first part 4, root side, and a second part 5, free end side 3 of the wing. Reference numerals 4 and 5 will indifferently denote the first and second portions of the leading edge region and the corresponding first and second developable controlled surfaces.

The next step of the method according to the present invention is to develop the first and second developable tuneable surfaces 4 and 5 so as to obtain two developed surfaces as illustrated in FIG. 2, where they are designated respectively by the reference numerals 4 'and 5 '. It is emphasized here that most CAD and CAD software have a surface development tool to develop developable tuneable surfaces. This step of the process therefore presents no difficulty in implementation.

As can be seen in the example shown, the developed surfaces 4 'and 5' still have the generatrices G and the segments T.

Since the T-segments are not useful for the manufacture of the protection elements according to the present invention, it is necessary to remove them, again easily using CAD and CAD software, so as to obtain surfaces developed 4 'and 5' having only the generators G as shown in FIG. Figure 3. Of course, this step will not be present when the initial model 1 does not include the T segments.

Depending on the length of the developed surfaces 4 'and 5', it may sometimes be advantageous to divide the developed surfaces 4 'and 5' into several so-called elementary developed surfaces, as illustrated in FIG. 4. In fact, each elementary developed surface will be used as a basis for the design and manufacture of a protective element and in the case of small aircraft it will be interesting to have protective elements that are not too long, for example less than 2 meters length, so as to be easily manipulated by an operator. In the case of large airplanes, such as an Airbus A380, it will be possible to provide much longer protection elements so as not to multiply the protection elements and thus to avoid the manipulations to be made by the operators to put in place. in place and remove the protective elements.

In the example illustrated in FIG. 4, the developed surface 4 'is divided into two elementary developed surfaces 4'i and 4' ₂ while the developed surface 5 'is divided into four elementary developed surfaces 5'i, 5' ₂ , 5 ' ₃ and 5' ₄ , so as to obtain elementary surfaces having a length of less than 2 meters.

The contour of each elementary surface 4'i, 4 _'2 5'i, 5' 2, 5 _'3 and 5' ₄ is defined by two opposite longitudinal edges 6a, 6b and two opposite transverse edges 6c, 6d.

The next step of the method according to the present invention consists in manufacturing protection elements 7 on the basis of the elementary surfaces 4 ' _1λ 4' ₂ , 5'i, 5 ' ₂ , 5 '3 and 5' 4, so as to obtain a set of protection elements 7 which can be installed end-to-end on the leading edge region whose outer surface is represented by the model 1, so as to cover said leading edge region of the free end 3 at the root end 2 of the wing A, as can be seen in Figure 5.

Referring now to FIG. 6, it can be seen that a protective element 7 according to the present invention is formed by a sheet-like block having first and second faces 7a, 7b opposite and whose contour corresponds to the contour of the corresponding elementary surface 4 'i, 4' ₂ , 5 'i, 5' 2, 5 ' ₃ and 5' ₄ . The first face 7a constitutes the face of the protection element 7 which faces outwards after the protective element 7 is placed on the wing A, whereas the second face 7b constitutes the face which will be in contact with wing A.

Slots 7c are made by any suitable means, for example using blades, lasers, etc., in the thickness of the protection element 7, starting from the first face 7a.

As can be seen in FIG. 6, the slits 7c are intended to allow the guard member 7 to be bent to conform very closely to the curvature of the leading edge region (designated B on 6), without generating excessive stresses in the material of which the protection element 7 is made. In other words, the whole of the second face 7b can be applied against the outer surface of the region of the leading edge B without damaging the integrity of the protection element 7. Each slot 7c is provided in the sheet-like block to the flat condition, along a ^"straight line which coincides with a respective generatrix G of the elementary surface 4 'i, 4' _2, 5 i, 5 ' 2, 5 ' ₃ and 5' ₄ corresponding.

Referring again to Figure 4, it can be seen that there can be a large number of generators G in the computer modeling and that there are not necessarily as many slots 7c in the element of 7 corresponding protection.

The choice of generators G that will be retained for the formation of corresponding slots 7c mainly depends on the radius of curvature of the region of the leading edge B to be protected and the capacity of the material forming the protective element 7 to be curved or bent without affecting his integrity.

It will be preferable to provide a greater number of slots in the zones of the protection element 7, the curvature of which will be greater once the protection element 7 is installed on the wing A, which will generally correspond to the edge of the protective element 7. attack B himself and his immediate vicinity. It can thus be seen in FIG. 6 that the spacing between the slits 7c is much smaller at the leading edge B than at the longitudinal ends of the protection element 7 which are farthest from the leading edge. B. Thus, generally, the pitch between the slots, namely the distance between two adjacent slots as measured in the width direction of the protection element 7, will increase as one moves away from the median longitudinal line of the protection element 7.

Consequently, it will generally be necessary to proceed with a cleaning of the modeling of the elementary surfaces 4 ' _1λ 4' ₂ , 5 'i, 5' ₂ , 5 ' ₃ and 5' ₄ , consisting of eliminate generators G which will not serve as a basis for the formation of slots 7c.

In addition to the number of slots 7c and their position relative to each other, the depth of the slots 7c will also play a role in the ability of the protection member 7 to bend without deteriorating. Again, the depth of the slits 7c will depend mainly on the radius of curvature of the region of the leading edge B to be protected and the capacity of the material forming the protective element 7 to be bent or bent without its integrity being affected. The deeper the slot 7c, the more it allows the two areas of the material which are situated on either side of the slot 7c, to deviate from one another and thus to bend the protective element 7 without risk of deterioration. It is emphasized here that this ability of the material to be bent or flexed without deterioration depends mainly on the material itself and its thickness.

As indicated above, there can be mentioned as an example of a suitable material a polyethylene foam, having a density preferably of between 15 kg / m ³ and 50 kg / m ³ , with a thickness of between 5 mm and 120 mm. Also as indicated above, the number of slots in this block example, their position and depth will depend on the profile of the leading edge region B to be covered.

It will thus be understood that, depending on the profile of the region of the leading edge B to be protected, the characteristics of the protective element 7 (material, thickness, characteristics of the slots such as number, position, depth ) by performing simple tests, with the above guidelines (decrease of the pitch and possibly increase of the depth allow to increase the capacity of the protection element 7 to bend without deteriorating).

It is emphasized here that, although the example illustrated in Figure 6 all the slots 7c have the same depth, it will be quite possible to provide slots 7c having different depths.

Finally, the protective elements 7 can be held in position on the wing A by any appropriate means, for example in the same way as the protection elements according to the prior art, namely by straps, fastening systems with loops and hooks or bungees. However, in view of the fact that the protection elements 7 according to the present invention perfectly match the leading edge region, it is advantageous to use adhesive means to temporarily fix the protection elements 7 to the wing A, for example double-sided adhesive tapes.

It is understood that the particular embodiment which has just been described has been given as an indication and not limitation and that modifications can be made without departing from the scope of the present invention.

Claims

A method of manufacturing sheet-like protective members (7) for application to the outer surface of the leading edge region (B) of an aircraft wing (A) so as to protecting said leading edge region (B), the latter having a radius of curvature which varies from the end (2) of the wing (A) on the root side to the free end (3) of the wing ( A), so that said outer surface is formed of at least one developable controlled surface (4, 5), the method being characterized by comprising:

a surface development step, in which, from a three-dimensional computer model of the outer surface of said leading edge region

(B), developing or each developable controlled surface (4, 5) forming said outer surface, so as to obtain one or more so-called developed surfaces (4 ', 5');

a generator determining step (G), in which generatrices (G) of the or each developable controlled surface (4, 5) are determined; and

a step of producing protection elements (7), in which, for the or each developable controlled surface, at least one sheet-like block is provided with slots (7c) which open out on the same surface (7a) of said at least one sheet-like block and which each extend along a straight line which coincides with a defined line segment, on the corresponding developed surface (4 ', 5'), by one of the generators (G) determined at the step of determining generators (G). 2 - Process according to claim 1, characterized in that, prior to the step of producing protection elements (7), one or more developed surfaces (4 ', 5') are divided into a plurality of so-called elementary developed surfaces. (4'i, 4 _'2 5'i, 5' _2, 5 _'3 5' _4), the slots (7c) being made of several blocks of sheet type, with a sheet-like block for each developed surface elementary (4 ' _ΐΛ 4' ₂ , 5'i, 5 ' ₂ , 5' ₃ , 5 ' ₄ ) ·

3 - Process according to any one of claims 1 and 2, characterized in that the slots (7c) are formed with a pitch between slots (7c) which increases as one deviates from the center line of the sheet type block.

4 - Process according to any one of claims 1 to 3, characterized in that the slots (7c) are made to have a depth of at least 50% of the thickness of the block-like sheet, depth measured at the right of said slot (7c), the thickness of the sheet-like block or blocks being for example between 5 mm and 120 mm.

5 - Process according to any one of claims 1 to 4, characterized in that the sheet or blocks of the type in which the slots (7c) are made are made of polymeric foam, preferably composed of polyethylene.

6 - Process according to any one of claims 1 to 5, characterized in that in the step of producing protection elements (7), is carried out in a block-type sheet intended to be applied on the outer surface of the leading edge region (B) located at the end (2) of the wing (A) on the root side, at least one secondary slot opening on the surface (7a) of said sheet-like block into which said slots (7c) open, the at least one secondary slot extending along a straight line which is perpendicular to the center line of said sheet-like block and the at least one secondary slot being located in the region of the edge of said sheet-like block which will be at the root end (2).

7 - Sheet-like protective member (7) intended to be applied to a portion of the outer surface of the region of a leading edge (B) of an aircraft wing (A), characterized in that it is obtained by the method according to any one of claims 1 to 6, so that it is in the form of a sheet-like block having slots (7c) which open on the same surface (7a). ) of the sheet-like block and which each extend along a straight line coinciding with a defined line segment, on the developed surface (4 ', 5') corresponding to the portion of the outer surface of the edge region of attack (B) intended to be covered by the protection element (7), by one of the generators (G) determined in the generator determining step (G).

8 - Protective element (7) according to claim 7, characterized in that the slots (7c) have a pitch between slots (7c) which increases as one deviates from the center line of the block type leaf.

9 - Protective element (7) according to any one of claims 7 and 8, characterized in that the slots (7c) have a depth of at least 50% of the thickness of the block-type sheet, depth measured at right of said slot (7c), the thickness of the sheet type block may for example be between 5 mm and 120 mm. 10 - Protection element (7) according to any one of claims 7 to 9, characterized in that the sheet-like block is polymeric foam, preferably composed of polyethylene.

11 - Protective element (7) according to one of claims 7 to 10, intended to be applied to the outer surface of the region of the leading edge (B) which is located at the end (2) of the wing (A) on the root side, characterized in that the sheet-like block forming the protection element (7) has at least one secondary slot which opens onto the surface (7a) of said sheet-like block into which said slots (7c), the at least one secondary slot extending along a line that is perpendicular to the center line of said sheet-like block and the at least one secondary slot being located in the edge region of said sheet-like block which will be located at the root end (2).

12 - A set of sheet-like protective members (7) intended to be applied to the outer surface of the region of a leading edge (B) of an aircraft wing (A) so as to protect said leading edge region (B), the protection elements (7) being as defined in one of claims 7 to 11 and thus obtained by a method as defined in one of claims 1 to 6, each protection element (7) corresponding to a developable controlled surface (4, 5) or, if appropriate, to an elementary developed surface (4'i, 4 ' ₂ , 5'i, 5' 2, 5 ' ₃ , 5 ₄ ), so that the protective elements (7) are able to be arranged end-to-end on the leading edge region (B) and to cover it substantially over its entire length.