AIRCRAFT SAIL PROFILE AND PROFILE MANUFACTURING METHOD

Abstract

Aircraft wing profile (1), connecting the lower surface (15) and the upper surface (13) of the wing (1) for separating the wing (1) into cells, characterized in that it comprises a flexible, supporting sheet cut into a streamlined shape giving the cross-section of the wing (1) when deployed, at least one reinforcing wire fixed at least at points to the flexible sheet, the reinforcing wire extending between the connection zone of the profile (17) to the upper surface (13) and the connection zone of the profile (17) to the lower surface (15), such that the reinforcing wire opposes its tensile strength to the stresses exerted between the lower surface (15) and the upper surface (13) during the flight of the aircraft. Figure for the abbreviation: Fig. 2

Description

Title of the invention: AIRCRAFT SAIL PROFILE AND PROFILE MANUFACTURING METHOD technical field

[0001] The invention relates to the field of aircraft sails of the parachute or paraglider type, and in particular to the method of assembling and structuring said sails. Prior art

[0002] For paragliding type aircraft, sails are known to have an intrados, an extrados, and profiles connecting the intrados to the extrados at regular intervals, thus forming substantially parallel longitudinal cells.

[0003] Profiles are pieces of cut fabric, arranged longitudinally and mainly vertically in the structure of the sail. When the aircraft is in flight, the lower and upper surfaces form the lower and upper surfaces of the wing formed by the sail, and the profiles retain the lower and upper surfaces, and their shape gives the sail its vertical longitudinal section, in the plane of the profile.

[0004] The profiles are subjected to potentially significant stresses during flight, and their strength as well as the strength of their attachment to the intrados and extrados are therefore crucial for the safety of the user.

[0005] The fabric of the profiles is notably based on woven synthetic polymer yarns, with warp and weft yarns substantially at right angles. The longitudinal section of the sail is curved, with stress forces mainly orthogonal to the local surface, and whose orientation varies continuously along the profile.

[0006] Thus, in the case of a profile cut from a piece of woven fabric, the stresses are oriented at a certain angle to the warp and weft threads. However, fabrics are strongest along the directions of the warp or weft threads, and are more deformable under forces acting along a diagonal direction (the "bias" of the fabric).

[0007] Thus, according to this prior art, profiles are obtained by cutting a fabric, for example with holes cut to allow air circulation between the cells of the sail. With this prior art, at least a part of the profile is subjected to stresses with forces along its bias.

[0008] Alternatively, profiles are known that consist of strips or fingers of fabric arranged and oriented so that their warp or weft threads are aligned with the expected axis of stress and fixed separately, for example by sewing to the intrados and extrados. Each profile then comprises a plurality of these strips or fingers, which must They must be correctly oriented and sewn on both the upper and lower surfaces. The assembly of the sail is therefore complex and expensive.

[0009] Aircraft sail fabrics are also relatively expensive fabrics, due to the important requirements they must meet: strength, deformability, lightness.

[0010] The profiles in cut strips, in addition to the numerous orientation and cutting steps required for their installation, also generate a significant amount of fabric waste. This waste adds to the production cost of the sail.

[0011] There is therefore a need for aircraft sail profiles that are simultaneously: strong, inexpensive to produce, and result in a sail that is easy to assemble. Summary of the invention

[0012] In order to address the technical problem mentioned above, the invention proposes an aircraft sail profile, connecting the lower and upper surfaces of the sail for the separation of sail cells, characterized in that it comprises a flexible sheet, forming a support, cut according to a profiled shape giving the section of the sail when deployed, at least one reinforcing wire fixed at least by points to the flexible sheet, the wire extending between the connection zone of the profile to the upper surface and the connection zone of the profile to the lower surface, so that the wire opposes its tensile resistance to the stresses exerted between the lower and upper surfaces during the flight of the aircraft.

[0013] The profiles thus obtained are strong because of the wire, whose tensile strength can be significant, and made of a single piece and easy to position during assembly, because they are supported by the flexible sheet support and are presented in one piece.

[0014] The wire can be oriented along the axes of the expected stresses for increased strength.

[0015] The profile according to the invention may further have one or more of the following characteristics, taken alone or in combination.

[0016] The flexible sheet can be made of non-woven textile, polymeric material, in particular polyamide or polyethylene terephthalate.

[0017] The flexible sheet can be made of porous material or perforated to allow the passage of air between neighboring cells of the sail, so as to balance the air pressure between said cells.

[0018] The reinforcing wire is advantageously a polyethylene wire with a very high molar mass.

[0019] The profile may include at least one reinforcing wire arranged in a fan shape with loops at the tip of said fan, located near the connection area of ​​the profile to the intrados, the loops forming an attachment for a sail suspension line.

[0020] The profile may include at least one wire formed of consecutive segments forming zigzags or crenellations along the entire profile.

[0021] The profile may include a rod forming the contour of a front part of the profile, attached to the flexible sheet, forming a leading edge of the sail during flight.

[0022] The profile may include: - a first layer of flexible sheeting, - reinforcing threads arranged on one side of the first layer of flexible sheet, - a second layer of flexible sheet, covering the glued reinforcing threads.

[0023] The profile with two layers of flexible sheet may further include a rod, forming the contour of a front portion of the profile in order to stiffen it, disposed between the two flexible sheets. This rod may be sewn onto the flexible sheet, or sandwiched between two flexible sheets joined by gluing or similar means, as appropriate.

[0024] The wires can be joined together by passing through the flexible sheet to form attachment points for said wires.

[0025] The invention also relates to the associated glider aircraft, characterized in that its sail comprises profiles, at least one of which is according to one of the preceding claims.

[0026] The invention also relates to the method of manufacturing a sail profile characterized in that it comprises the following steps: - Defining the profile outline on a flexible sheet, - fixing on said sheet of wires extending between two regions of the profile contour - cutting said support according to the contour of said aircraft sail profile.

[0027] Other features and advantages of the profile and its method of production will become apparent from the description of the figures below. The embodiments shown are given by way of illustration and are not intended to be limiting. Other embodiments can easily be obtained by variations and combinations of the embodiments shown. Brief description of the figures

[0028] [Fig. 1] is a schematic representation of a paraglider-type glider aircraft in flight.

[0029] [Fig.2] is a schematic exploded view representation of a sail with profiles,

[0030] [Fig.3] is a schematic representation in lateral view of a sail profile according to one aspect of the invention,

[0031] [Fig.4] is a schematic representation in lateral view of a sail profile according to a second aspect of the invention,

[0032] [Fig.5] is a schematic lateral view representation of a sail profile according to a third aspect of the invention,

[0033] [Fig.6],

[0034] [Fig.7], and

[0035] [Fig.8] illustrate the process of obtaining a sail profile as previously mentioned,

[0036] [Fig.9] illustrates a profile embodiment with several reinforcing wires,

[0037] [Fig. 10] illustrates another method for obtaining the sail profile with several reinforcing threads,

[0038] Detailed description of the figures

[0039] As illustrated in [Fig.1], the paraglider 100 essentially comprises a sail 1, to which lines 3 are attached, and a harness 5 located under the sail 1 and attached to it by the lines 3.

[0040] The wing 1 is a flexible wing in the shape of a curved wing, having a leading edge L at the front and a trailing edge T at the rear. The user U is seated in the harness 5, and pilots the paraglider 100 by pulling on certain lines 3, which modifies the shape and behavior of the wing 1.

[0041] The harness 5 is here a streamlined harness 5, rigid or semi-rigid, encompassing the legs and at least the pelvis of the user U.

[0042] Sail 1 is divided into cells 11, which extend longitudinally and parallel to each other.

[0043] Fig. 2 is a schematic exploded view representation of a sail 1. The sail 1 essentially comprises a strip of fabric forming the extrados 13, a strip of fabric forming the intrados 15, and a plurality of profiles 17.

[0044] The profiles 17 have a teardrop or comma shape, with a bulging part at the front, and a tapered part at the rear, and structure the sail 1 when they are sewn to the strips forming the extrados 13 and the intrados 15. The cells 11 are thus separated by the profiles 17 once the sail 1 is assembled.

[0045] Other additional structural elements can be used, for example diagonals, connecting two opposite corners of a cell 11 diagonally. Cross members can also connect two adjacent profiles 17, forming an H shape with them. The diagonals and cross members can be made in the manner developed below in relation to the profiles 17.

[0046] Fig. 3 is a schematic representation of a profile 17. The profile 17 includes a support cut from a flexible sheet 7, having a shape corresponding to the section to be given to the sail 11 when it is inflated.

[0047] The flexible sheet 7 is, for example, a sheet of non-woven textile or of polymeric material, in particular polyethylene terephthalate. In particular, the flexible sheet 7 does not have to be made of Kevlar® or very high molecular weight polyethylene (“Dyneema®”) with a ripstop weave like the rest of the sail 1, or of another equivalent material commonly used in the design of sails 1: woven polyamide or polyester, multidirectional woven fabric, etc.

[0048] The flexible sheet 7 is advantageously made of porous materials, in order to allow air circulation between neighboring cells 11, separated by the profile 17. Thus, the air pressure can be balanced between the different cells 11, which improves the inflation and the dynamic behavior of the sail 1. As an alternative or in addition, the flexible sheet 7 can be perforated to allow better pressure balancing.

[0049] Once the sail 1 is assembled, the profile 17 is sewn from the stop point (intersection of the profile 17 and the leading edge L) to the trailing edge T on the upper surface 13 and on the lower surface 15. Dashed lines delimit in [Fig. 3] a peripheral connection zone which will be stitched to the bands forming the lower surface 15 and the upper surface 13, thus defining a connection zone to the upper surface 13 and a connection zone to the lower surface 15.

[0050] A elastically constrained rod 9 is attached to the front of the profile 17, stiffening the leading edge L and giving it its shape. The profile 17 is of the "sharknose" type, with a recess at the leading edge L where overpressure is created, improving the rigidity and dynamic behavior of the sail. Sails 1 with such a shape are described, for example, in document FR2972422.

[0051] Other shapes of the rod 9 are of course possible, as is the absence of a rod 9.

[0052] The rod 9 is notably obtained by folding an initially straight rod into a loop, with the two free ends of the loop crossing towards the inside of the loop. The rod 9 is, for example, glued to the flexible sheet 7 or sewn to it.

[0053] A reinforcing thread 10 is attached by stitches to the flexible sheet 7 and connects, by means of straight segments at regular intervals, the connection zone on the upper surface 13 and the connection zone on the lower surface 15. The reinforcing thread 10 is, for example, a polyethylene thread with a very high molar mass, sheathed to resist ultraviolet radiation, for example by enzymatic coating. The reinforcing thread 10 is, for example, sewn by relatively widely spaced stitches (several centimeters) to the flexible sheet 7, or else glued at least by stitches to said flexible sheet 7.

[0054] According to a particular embodiment, two reinforcing wires 10, arranged on opposite faces of the flexible sheet 7, are provided and are joined together in crossing the flexible sheet 7 to come into mutual contact by crossing said flexible sheet 7 at regular intervals.

[0055] By connecting the connection zone to the upper surface 13 and the connection zone to the lower surface 15, the reinforcing thread 10 opposes its tensile strength to the stresses exerted between the lower surface 15 and the upper surface 13 during flight. The diameter of the reinforcing thread 13 can, in particular, be larger than the diameter of the threads used to weave the fabric used in conventionally made sails 1, because, since this thread is not woven, the weight stress is much lower for the reinforcing thread 10, of which only a relatively small length is used compared to the lengths of warp and weft threads in a fabric.

[0056] In [Fig.3], the reinforcing wire 10 is arranged in a continuous zigzag pattern, with points located in the connection zones to the upper surface 13 and the lower surface 15. When stitching the profile 17 to the upper surface 13 or the lower surface 15, a stitch is advantageously located at each of the points, so that the stitching thread is engaged with the reinforcing thread 10. The orientations between successive sections of the zigzag are determined to optimize the transmission of stresses in flight. These orientations are generally not perpendicular.

[0057] The gap e between two successive points at an edge of the profile 17 can be adjusted according to the properties of the reinforcing wire 10 and the expected stresses. The smaller the gap e, the higher the strength will be for the same type of reinforcing wire 10, while the larger the gap e, the lower the strength will be, but the total weight of wire used will be lower.

[0058] In [Fig. 4] a profile 17 is shown according to another embodiment. This mode The realization differs from that of [Fig.3] in that the reinforcing wire 10 is arranged in crenellations, with vertical segments connecting the connection zones to the extrados 13 and the intrados 15, and with horizontal segments located in said connection zones to the extrados 13 or the intrados 15, which connect the vertical segments two by two.

[0059] The horizontal segments are, once the sail 1 is assembled, engaged with the seams of the profile 17 at the band forming extrados 13 or intrados 15.

[0060] In [Fig. 5] another arrangement of reinforcing wire 10 for fastening is shown. Suspension lines 3. In this particular arrangement, the reinforcing wire 10 is fanned out with loops 19 at the apex of said fan. The apex of the fan and the loops 19 are located at the level of the intrados 15 and extend beyond it. The loops 19 can then be used to attach the suspension lines 3.

[0061] In particular, the reinforcing wire can make several overlapping loops, which makes it possible to generate a solid attachment point to the suspension 3.

[0062] Figures 6 to 9 illustrate the main steps in the process of manufacturing a profile as described above.

[0063] The first step is the cutting or delimiting of the profile in the flexible sheet 7 to form the support. A cut or delimited flexible sheet support is shown in [Fig.6].

[0064] The second step is the attachment of the reinforcing wire 10 to the flexible sheet support 7. This attachment can be carried out in several different ways: gluing, sewing, etc.

[0065] A flexible sheet support 7 with a reinforcing wire fixed is shown in [Fig.7] The reinforcing wire 10 is here arranged in a zigzag pattern, with points in the stitching areas on the intrados and extrados.

[0066] The third step is the placement of the rod 9, by gluing or sewing, at the front end of the flexible sheet support 7. The profile 17 thus obtained is shown in [Fig.8].

[0067] According to a particular embodiment, the flexible sheet 7 is cut into the shape of profile 17 only as a final step, after the reinforcing wire 10 and the rod 9 have been installed. The flexible sheet 7 can then be handled with one or more profiles 17 materialized on it but not yet cut, particularly in an automated manner, between workshops performing the various steps described above. The cutting of the profiles 17 can then be carried out as the very last step, particularly in a workshop assembling the paraglider 100.

[0068] Figure 9 illustrates a possible additional step. In this additional step, a second reinforcing wire 10 is attached to the flexible sheet 7 forming a support, here in the fan pattern forming loops for attaching the suspension wires 3.

[0069] Fig. 10 illustrates an alternative embodiment of a method for assembling a profile 17 similar to that of Fig. 9.

[0070] In this process, two flexible sheets 7 cut out and provided with reinforcing threads 10 are glued together.

[0071] The two cut flexible sheets 7 are joined together, for example by gluing, thermal welding, or ultrasonic welding. The reinforcing wires 10 are arranged mainly on the faces of the flexible sheets 7 that are glued together, so that the reinforcing wires 10 are covered and protected by the flexible sheets 7 that cover them.

[0072] The rod 9 is in particular arranged and sandwiched between the two flexible sheets 7 and attached to them by gluing or welding when the two flexible sheets 7 are assembled into one.

[0073] The flexible sheets 7 can in particular thus protect the reinforcing wires 10 and the rod against the ultraviolet radiation of the sun.

[0074] The profiles 17 according to the invention and the sail 1 for the paraglider 100 or associated aircraft are durable, lighter or stronger at equal weight.

Claims

Demands

1. Aircraft wing profile (100), connecting the lower surface (15) and the upper surface (13) of the wing (1) for separating the wing (1) into cells (11), comprising a flexible sheet (7), forming a support, cut in a streamlined shape giving the cross-section of the wing (1) when deployed, at least one reinforcing wire (10) fixed at least at points to the flexible sheet (7), the reinforcing wire (10) extending between the connection zone of the profile (17) to the upper surface (13) and the connection zone of the profile (17) to the lower surface (15), such that the reinforcing wire (10) opposes its tensile strength to the stresses exerted between the lower surface (15) and the upper surface (13) during the flight of the aircraft (100), characterized in that it comprises at least one reinforcing wire (10) arranged in a fan shape with loops at the tip of said fan, located near the connection area of ​​the profile (17) to the intrados (15), the loops forming attachment for suspension lines (3) of the sail (1).

2. Sail profile according to the preceding claim, characterized in that the flexible sheet (7) is made of non-woven textile, or of polymeric material, in particular of polyethylene terephthalate.

3. Sail profile according to the preceding claim, characterized in that the flexible sheet (7) is made of porous material or perforated to allow the passage of air between cells (11) close to the sail (1), so as to balance the air pressure between said cells (11).

4. Sail profile according to any one of the preceding claims, characterized in that the reinforcing yarn (10) is a polyethylene yarn of very high molar mass.

5. Sail profile according to any one of the preceding claims, characterized in that it comprises at least one reinforcing wire (10) arranged in consecutive segments forming zigzags or crenellations along the entire profile (17).

6. Sail profile according to any one of the preceding claims, characterized in that it comprises a rod (9) forming the contour of a forward part of the profile (17), attached to the flexible sheet (7), forming a leading edge (L) of the sail (1) during flight.

7. Sail profile according to any one of the preceding claims, characterized in that it comprises: - a first layer of flexible sheet (7), - reinforcing wires (10) arranged on one face of the first layer of flexible sheet (7), - a second layer of flexible sheet (7), covering the reinforcing wires (10) arranged on the first layer of flexible sheet (7).

8. Profile according to any one of the preceding claims, characterized in that it comprises at least two reinforcing wires (10), each arranged on one face of the flexible sheet (7), the reinforcing wires (10) being interlaced with each other by passing through the flexible sheet (7) to form attachment points for said reinforcing wires (10).

9. Sail aircraft, characterized in that its sail (1) comprises profiles (17), at least one of which is according to one of the preceding claims.

10. A method for manufacturing a sail profile according to any one of claims 1 to 9, characterized in that it comprises the steps: - defining the profile contour (17) on a flexible sheet (7), - fixing on said flexible sheet (7) reinforcing threads (10) extending between two regions of the profile contour corresponding to the assembly of the sail (1) at the seam areas with the intrados (15) and the extrados (13), - cutting said support according to the contour of said sail profile (17) of aircraft (100), - arranging on the support at least one reinforcing thread (10) arranged in a fan shape with loops at the tip of said fan, located near the connection area of ​​the profile (17) to the intrados (15), the loops forming attachments for lines (3) of the sail (1).

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