FR3066529B1 - METHOD OF MANUFACTURING WING ATTACK EDGE PROTECTION ELEMENTS, PROTECTIVE ELEMENT OBTAINED BY THE METHOD AND SET OF SUCH PROTECTIVE ELEMENTS - Google Patents

Abstract

The invention relates to a method of manufacturing protection elements (7) for application on the outer surface of the region of a leading edge of a wing (A) to protect it, said region having a radius of curvature variable so that said outer surface is formed of at least one developable controlled surface. The method comprises a step in which, from a three-dimensional computer model of the outer surface, the developed one or each developable surface is developed, a step in which generators of the developable regulated surface (s) are determined, and a step in wherein, for each developable set surface, slots (7c) each extending along a straight line coinciding with a line segment defined by one of the generators are provided in at least one sheet-like block. The invention relates to a protective element (7) obtained by this method and a set of such protection elements (7).

Description

METHOD OF MANUFACTURING WILD 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 an edge of attack of a wing of an aircraft when the latter estimatedmobilized on the ground, and a protection element obtained by this method and a set of these protection elements intended to cover the entire edge of attack of a wing.

When maintenance operations must be performed on an aircraft, depriving it of 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 the operators tomorrowtenance. These numerous displacements occur near the plane, and in particular the leading edge of the wings which is particularly exposed. However, the edge of attack is an essential part of the plane and the fault can compromise the behavior of the aircraft in flight. It is therefore essential to have a protective element on the leading edge to prevent shock damage it.

It is known to protect the leading edge by sheet-like or flat-type foam protection elements, which are placed next to each other and facing the leading edge and the region in the vicinity thereof, hereinafter referred to by "leading edge area" so as to completely cover it. The protective elements are held in position, for example by straps around the wing, by fastening systems loops etcrochets (Velcro® type), by bungees, etc.

Each protection element is manufactured by cutting, wire or machining, in a foamed block, in a profile corresponding substantially 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.

The different elements are then glued end to end, then the inner faces, namely that intended to become in contact with the wing, and external are covered with two thin skins, 3 to 10 mm thick, glued while being stretched, the skins allowing to make connection 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 sections of wing constant profile, which is rarely the case on aileil aircraft.

Thus, these protection elements have some disadvantages when installed on a leading edge region of a wing having a variable profile. First, the shape of the elements does not allow them to conform to the shape of the edge region of attack, 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 when cutting the solid blocks. Finally, their manufacture is long, because after cutting, it is then necessary to peel the skins, wait for the glue dries, etc.

The present invention aims to solve the problems encountered with the conventional protection elements described above and to provide protection elements very closely matching 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 closely approximated by), with the exception of the root, either a settable surface or can be decomposed. in a plurality of adjacent developable trimmed surfaces in the wing span direction, and that the outer surface geometry can thus be defined using generatrix extending generally in the wingspan direction. At the nurse is usually a leave of absence.

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 leading edge region, the slots each extend along a spacecraft, which allows the guard member to be curved, without being damaged, to closely conform to the outer surface of the edge edge region.

It is therefore an object of the present invention to provide a wall-type protective member for application to the outer surface of the region of a leading edge of an aircraft wing to protect said edge region. etching, the latter having a radius of curvature which varies from the wingtip end to the free end of the wing, such that said outer surface is formed of at least one developable controlled surface, the method being characterized by the it comprises: - a surface development step, in which, starting 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 to obtain one or more so-called developed surfaces; a step of determining generators, in which generatrices of the or each developable controlled surface are determined; anda step of producing protection elements, in which, for the or each developable controlled surface, is produced in at least one sheet-like block, slots which open on the same surface of said at least one sheet-like block and which extend each along a straight line coinciding with a straight line segment, on the corresponding developed surface, by one of the generators determined in the step of determining generators.

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

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

The slots may be made to 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 or blocks may for example be between 5 mm and 120 mm.

Preferably, the one or more foil-type blocks in which the slots are made may be polymeric foam, preferably polyethylene.

Preferably, in the step ofproducing protection elements, there is provided, in a wall-type block for application to the outer surface of the leading edge region at the end of the root-side wing, 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 located at the root end.

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

The present invention also relates to a sheet-like protection element intended to be applied to a part 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 slits which project on the same surface of the sheet-like block and which each extend along a line coinciding with a segment of defined line, 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 generatricesdepended in the generator determining step.

Advantageously, the slots have a slot gap which increases as one deviates from the median line of the sheet-like block.

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

Preferably, the sheet type block may be polymeric foam, preferably polyethylene.

Preferably, for a protective element intended to be applied to the outer surface of the leading edge region which is at the end of the root side wing, the sheet-like block forming the protection element has at least one secondary slit which opens onto the surface of said wall block into which said slots open, the at least one secondary slot extending along a line perpendicular to the center line of said wall block and the at least one secondary slot being located in the region of the edge of said wall leaf-like block that will strike at the root end.

The present invention also relates to a set of sheet-like protective members for application to the outer surface of the region of a leading edge of an aircraft wing so as to protect said leading edge region, the protection elements being as defined above and thus obtained by a method as defined above, each protection element corresponding to a controlled surface or, if appropriate, to an elementary developed surface, so that the protective elements are suitable to be disposed end to end on the edge of attack area and cover it substantially on any salongeur.

To better illustrate the subject of the present invention, will be described below, by way of indication and not limited to, a particular embodiment with reference to the accompanying drawing.

In this drawing: FIG. 1 is a perspective view of a dimensional model, in a wire view, of the edge region of an aircraft wing; FIG. 2 is a view of two developed surfaces, taken from the leading edge region model which has been developed and divided in two, according to a step of the method according to the present invention, and on which generatrices and transverse segments appear; 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 elemental developed surfaces from the two developed surfaces of Figure 3; FIG. 5 is a perspective view of an aircraft airframe and a portion (shown schematically) of the aircraft fuselage, protection elements obtained by the method according to the present invention being applied to the edge region of the aircraft; modelized attack in Figure 1; and FIG. 6 is a sectional cross-sectional view of the wing of FIG. 5, showing the leading edge region and a protective member 7 placed 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 side aircraft left, 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 an example and the present invention is not limited to the specific geometry of this leading edge region. Moreover, for the sake of brevity, the characteristics of the leading edge region and the modelizations of those of the model 1 will be designated by the same reference numerals.

Model 1 can be obtained by any appropriate means.

In general, 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 quite possible, while still within the scope of the present invention, to model the region of the edge of attack of a wing by digitizing it by means of a scanning-type device (3D scanner / 3D camera) or by taking measurements of the geometry of the leading edge region 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 segmentstransversales T parallel to the longitudinal direction of the aircraft and thus in the direction of the airflow around the wing. Such a representation is included because the outer surface of the leading edge region is a developable or divisible adjustable surface, in the direction of the wing span, into a plurality of controllable developing surfaces.

It is recalled that a regulated surface is a surface through which each point passes a straight line, called a generatrix, 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 sliding" the surface of the region of the leading edge on a plane, the contact being along a line called generator.

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

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 model 1 is shown in FIG. 1, the leading edge region has a longitudinal directional change about 1/3 of its length from its root end 2, and it can thus be divided into first and second developable adjustable surfaces defining two parts of the edge region of attack: a first part 4, root side, and a second part 5, free end side 3 of the wing. The reference digits 4 and 5 will indifferently denote the first and second portions of the leading edge region and the corresponding first and second corresponding developable surfaces.

The next step of the method according to the present invention is to develop the first and second developable settable surfaces 4 and 5 so as to obtain two developed surfaces as illustrated in FIG. 2, in which 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 for developing developable set surfaces. This step of the process therefore does not pose any difficulty of implementation.

As can be seen in the example shown, the developed surfaces 4 'and 5' still have the generators 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 the CAD and CAD software, so as to obtain developed surfaces 4 ' and 5 'only representing 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 serve as a basis for dimensioning and manufacturing of a protective element and in the case of small-sized aircraft it will be interesting to have protective elements which are not too long, for example less than 2 meters in length, so that they can be handled easily by an operator. In the case of larger aircraft, such as an Airbus A380, much longer protection elements may be provided in order not to multiply the protection elements and thus to avoid manipulations to be made by the operators to set up and remove the elements. protection.

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 elementarydeveloped 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% 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'i, 4'2, 5'i, 5'2, 5'3 and 5%, so as to obtain a set 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 the leading edge region of the free end 3 at the end of root 2 of 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 opposite first and second faces 7a, 7b and whose contour corresponds to the contour of the elementary surface4'χ, 4'2, 5'i, 5'2, 5½ and corresponding 5%. The first surface 7a constitutes the face of the protective element 7 which is turned outwardly after the protective element 7 is put in place on the wing A, while the second face 7b constitutes the face which will be in contact with the wing A.

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

As can be seen in FIG. 6, the purpose of the slits 7c is to allow the protector element 7 to be bent to conform very closely to the curvature of the leading edge region (designated B in FIG. 6). without causing excessive stress in the material of which the protection element 7 is made. In other words, the whole of the second face 7b may be applied against the outer surface of the region of the leading edge B without damaging the integrity of the element protection 7.

Each slot 7c is made in the flat-sheet block in a flat state along a straight line coinciding with a respective generator G of the elementary surface 4 ', 4'2, 5'i, 5'2, 5 3 and 5% corresponding.

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

The choice of generators G to be preserved for the formation of corresponding slots 7c depends mainly on the radius of curvature of the region of the edge of attack B to be protected and the capacity of the material forming the protection element 7 to be bent or flexed in its integrity is affected.

It will be preferable to provide a greater number of slots in the areas of the protection element7, the curvature of which will be greater once the protection element 7 is installed on the wing A, which generally corresponds to the leading edge B itself. same and to 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 the farthest from the leading edge B. Thus, generally, the pitch between the slots, namely the distance between two adjacent slits as measured in the width direction of the protection element 7, will increase as one moves away from the longitudinal middle line of the element protection 7.

Therefore, it will usually be necessary to clean the modeling of the elementary surfaces 4'x, 4'2, 5'i, 5'2, 5% and 5'4, consisting of eliminating the generators G which will not serve as base to the formation of slits 7c.

In addition to the number of slots 7c and their position relative to each other, the depth of the slits 7c will also play a role in the ability of the protection element 7 to bend without deteriorating. Again, the depth of the slits 7c will depend mainly the radius of curvature of the region of the edge of attack B to be protected and the capacity of the material forming the protection element 7 to be bent or bent without affecting its integrity. The deeper the slot 7 is, the more it allows the two areas of the material which are located on either side of the slot 7c, to distance from one another and thus to bend the protection element 7 without risk of deterioration. It is emphasized that this ability of the material to be bent or bent 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 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 slits practiced in this block example, their placement and depth will depend on the profile of the leading edge region B to be covered.

It will therefore be understood that, depending on the profile of the region of the leading edge B to be protected, the characteristics of the protection element 7 (material, thickness, characteristics of the slits such as shadow, position, depth) can be determined by realizing simple tests, with the above guidelines (decrease of the pitch and possibly increase of the depth make it possible to increase the capacity of the protection element 7 to be rescued 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 7changing different depths.

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

It is understood that the particular embodiment which has just been described has been givenindicative and not limiting and that modifications can be made without departing from the scope of the present invention.

Claims (3)

1 - Method for manufacturing sheet-like protective elements (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 the leading edge region (B), the latter having a bending radius which varies from the end (2) of the wing (A) towards the free end (3) of the wing (A), from 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 from 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-calleddeveloped 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 configurable surface, at least one wall-type block is made of slots (7c) which open on a same surface (7a) of said at least one sheet-like block, each extending along a straight line coinciding with a defined line segment, on the corresponding expanded surface (4 ', 5'), by one of the generators (G) determined at the step of determination of generators (G). 2 - Process according to claim 1, characterized in that, prior to the step ofproduction of protection elements (7), one or more developed surfaces (4 ', 5') are divided into a plurality of so-called elementary surfaces (4'4 , 4'2, 5'4, 5'2, 5'3,5'4), the slots (7c) being made in a plurality of sheet-like blocks, with a sheet-like block for each elementary expanded surface (4'4, 4'2, 5'4, 5'2, 5'3.5'4). 3 - Process according to any one of the claims 1 and 2, characterized in that thefentes (7c) are made with a pitch between slots (7c) which increases as one deviates from the median linede type block leaf. 4 - A method according to any one of claims 1 to 3, characterized in that lesfentes (7c) are made to have a depthreprésentant at least 50% of the thickness of the wallet block, depth measured at the right of said slot (7c ), the thickness of the sheet-like block or blocks, for example, being between 5 mm and 120 mm. 5 - Process according to any one of claims 1 to 4, characterized in that the orblocs of the sheet type in which the slots (7c) sontréalisés are polymeric foam, preferably composed of polyethylene. 6 - Process according to any one of Claims 1 to 5, characterized by the fact that in the step of realization of protection elements (7), it is made in a block of sheet type intended to be applied to the outer surface of the region of the leading edge (B) located at the end (2) of the wing (A) root side, at least one secondary slot which opens on the surface (7a) of said sheet-like block into which said slots (7c), the at least one secondary slot extending along a straight line which is perpendicular to the center line of said sheet block and the at least one secondary slot being located in the edge region of said sheet block which will be at the end (2) end side. 7 - Leaf-type protection element (7) to be applied on part 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 wall-type block having slots (7c) which open on a same surface (7a) of the block type sheet and extending each along a straight line coinciding with a defined right-hand segment on the developed surface (4 ', 5') corresponding to that portion of the outer surface of the leading edge region (B) to be covered by the protection element (7), by one of the generators (G) determined in the generator determining step (G). 8 - Protection element (7) according to larevendication 7, characterized in that the slots (7c) have a pitch between slots (7c) which increases to measure that one deviates from the center line of the block type sheet. 9 - Protective element (7) according to any one of claims 7 and 8, characterized by the fact that the slots (7c) have a depth representing 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 being for example between 5 mm and 120 mm. 10 - Protective element (7) according to any one of claims 7 to 9, characterized in thatthe sheet-like block is made of polymeric foam, preferably composed of polyethylene. 11 - Protection 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) located at the end (2) of the wing (A at the root side, characterized in that the sheet-like block forming the protective element (7) has at least one secondary slot which opens out onto the surface (7a) of said sheet-like block into which said slots (7c), the at least one secondary side-extending slot perpendicular to the center line of said sheet-type 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). 12 - A set of sheet-like protective members (7) to be applied to the outer surface of the leading edge region (B) of an aircraft wing (A) so as to protect said region Attack edge (B), the protective 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%), so the protection 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.