Aircraft assembly

Abstract

An aircraft assembly comprising: a rib (10) of a wing; an aperture (11) in the rib; a conduit assembly (30a, 30b) extending through the orifice, the conduit assembly comprising a first rigid conduit section (30a), a second rigid conduit section (30b), and a flexible conduit section (33) located between the first rigid conduit section and the second rigid conduit section; and a securing device (25) coupling one of the duct sections to a rib (10) of the wing wherein a flexible duct section (33) is located at the plane of the rib and is configured to allow relative movement between the first rigid duct section and the second rigid duct section.

Description

Technical Field

[0001] The invention relates to an aircraft component, an aircraft wing comprising an aircraft component and an aircraft comprising an aircraft wing. Background Art

[0002] There are many alternative fuels that are thought to help achieve future emissions targets, one such approach being the use of hydrogen fuel. The cryogenic temperatures required for hydrogen fuel means that the pipeline is at a much lower temperature than the surrounding atmosphere, and this can result in significant shrinkage of the pipeline.

[0003] Fuel pipes extending along aircraft wings are usually fastened to ribs, thereby fixing the pipes in place relative to the ribs. Therefore, any contraction of the pipes results in loads being transferred to the ribs. Similarly, the aircraft wing bends and twists during use, causing the pipes to bend and twist accordingly. The pipes resist this movement and transfer the resulting loads into the ribs. These loads need to be taken into account when designing the ribs.

[0004] Additionally, hydrogen fuel pipes typically have a greater thickness than conventional fuel pipes, and this may further increase the loads transferred to the ribs. Summary of the invention

[0005] A first aspect of the present invention provides an aircraft assembly comprising: a rib of a wing; an aperture located in the rib; a duct assembly extending through the aperture, the duct assembly comprising a first rigid duct segment, a second rigid duct segment, and a flexible duct segment located between the first rigid duct segment and the second rigid duct segment; and a fixture connecting one of the duct segments to the wing rib, wherein the flexible duct segment is located at the plane of the rib and is configured to allow relative movement between the first rigid duct segment and the second rigid duct segment.

[0006] By this arrangement, relative movement between the rigid duct sections on either side of the wing rib is allowed while substantially transferring no loads to the wing rib. Positioning the flexible duct sections at the plane of the rib ensures maximum mobility of the rigid duct sections on either side.

[0007] The first rigid duct section may be fixed relative to the rib and the second rigid duct section may be movable relative to the rib. This secures at least a portion of the duct assembly to the wing rib and prevents excessive axial movement of the duct assembly.

[0008] The fixing device may include a first joining section fixedly attached to the first rigid pipe segment and a second joining section fixedly attached to the second rigid pipe segment, wherein the first joining section is configured to contact the second joining section and maintain the contact during relative movement between the first rigid pipe segment and the second rigid pipe segment.

[0009] By means of such an arrangement, a relatively fixed distance can be maintained between the second rigid pipe section and the rib, thereby avoiding collision between the second rigid pipe section and the rib.

[0010] The first and second engagement sections may overlap at the plane of the ribs. This ensures that contact between the engagement sections is at, or at least close to, the plane of the ribs and thereby maximizes the permitted movement of the second rigid pipe section without collision.

[0011] The first engagement section may include a planar profile and the second engagement section may include a curved profile, wherein the first engagement section and the second engagement section are in contact at a bearing surface between the planar profile and the curved profile.

[0012] By this arrangement, contact between the engaging sections is minimized, resulting in reduced friction.The curved profile may also facilitate rotation of the second rigid pipe section relative to the rib about an axis perpendicular to the plane of the rib.

[0013] The duct assembly may be an outer duct assembly, and the aircraft assembly may include an inner duct assembly enclosing the outer duct assembly.

[0014] By such an arrangement, a thermal barrier may be provided between the inner and outer pipe assemblies. This may be particularly beneficial for hydrogen fuels and other fuels maintained at cryogenic temperatures.

[0015] The inner pipe assembly may include a first rigid pipe section, a second rigid pipe section, and a flexible pipe section located between the first rigid pipe section and the second rigid pipe section. Thus, the inner pipe assembly may bend and twist together with the outer pipe assembly.

[0016] The pipe assembly may be configured to transport hydrogen fuel. The cryogenic temperatures required for hydrogen fuel require thickening of the fuel pipe and / or constriction of the pipe, which increases loads that may otherwise be transmitted to the ribs.

[0017] The inner pipe assembly is configured to transport hydrogen fuel. This allows the space between the inner pipe assembly and the outer pipe assembly to serve as a thermal barrier.

[0018] The hydrogen fuel may be liquid hydrogen fuel.

[0019] The hydrogen fuel may be gaseous hydrogen.

[0020] The inner pipe assembly can be spaced apart from the outer pipe assembly. This ensures that there is no contact between the pipe assemblies and thereby reduces heat transfer between the pipe assemblies.

[0021] The space between the inner and outer tubing assemblies may include a vacuum or an inert gas.

[0022] The fixing means may comprise a substantially non-conductive material configured to isolate the rib from the pipe assembly. This ensures that there is no metal-to-metal contact on the assembly and thereby provides lightning surge protection. The material may be a non-conductive polymer material. Polymer materials may be lighter than equivalent metal components but generally have less rigidity. However, the reduced loads transferred to the rib make polymer materials suitable.

[0023] The pipe assembly may be continuous over the ribs. Couplings and other devices that are not integrally formed are generally undesirable because they increase the risk of leakage. This is particularly true for cryogenic pipes, which ideally avoid any sealing between pipe sections.

[0024] The fixing means may be configured to restrict movement of at least a portion of the duct assembly in the longitudinal direction and to allow rotation of the duct assembly relative to the rib. This may supplement the relative movement provided by the flexible duct section.

[0025] The fixing device may be configured to allow rotation of the duct assembly relative to the rib about a longitudinal axis extending in the longitudinal direction. By this arrangement, the fixing device reduces or alleviates the load in the duct caused by the torsion of the wing.

[0026] The fixture may be configured to allow rotation of the duct assembly relative to the rib about two perpendicular axes, and preferably about three perpendicular axes. This allows the fixture to reduce or mitigate further loads caused by bending and / or twisting of the wing.

[0027] The fixture and the rib may have corresponding curved surfaces forming a bearing surface between the fixture and the rib so as to allow rotation of the duct assembly relative to the rib.

[0028] The bearing surface may be formed by a protruding part of the fixing means and a concave part of the rib. This is one way of providing a curved bearing surface.

[0029] Optionally, the flexible conduit section comprises a bellows conduit.

[0030] Optionally, the fixing device comprises a spherical bearing surface which allows a rotation of one of the pipe segments relative to the rib.

[0031] Optionally, the securing means comprises a ball and socket joint.

[0032] Optionally, the ball and socket joint comprises a ball located in a socket, and one of the pipe sections is coupled to the ball.

[0033] A second aspect of the invention provides an aircraft wing comprising the aircraft assembly of the first aspect.

[0034] An aircraft wing may comprise a plurality of aircraft components according to the first aspect.

[0035] A third aspect of the invention provides an aircraft comprising the aircraft wing of the second aspect.

[0036] A fourth aspect of the present invention provides an aircraft component, which includes: an aircraft structure; a pipe assembly, which includes a first rigid pipe section, a second rigid pipe section, and a flexible pipe section extending between the first rigid pipe section and the second rigid pipe section, wherein the flexible pipe section is configured to allow relative movement between the first rigid pipe section and the second rigid pipe section; and a fixing device, which connects the first rigid pipe section to the aircraft structure, and the fixing device includes a spherical bearing surface, which allows the first rigid pipe section to rotate relative to the aircraft structure.

[0037] Optionally, the flexible pipe section is configured to allow relative translation between the first rigid pipe section and the second rigid pipe section in an axial direction, wherein the axial direction is parallel to a longitudinal axis of the first rigid pipe section or the second rigid pipe section.

[0038] Optionally, the assembly is configured to allow relative rotation between the first rigid duct segment and the second rigid duct segment about a transverse axis, wherein the transverse axis is perpendicular to the longitudinal axis of the first rigid duct segment.

[0039] Optionally, the securing means comprises a ball and socket joint.

[0040] Optionally, the ball and socket joint comprises a ball located in a socket, and the first rigid pipe section is coupled to the ball.

[0041] Optionally, the aircraft assembly further comprises a first joining segment fixedly attached to the first rigid duct segment and a second joining segment fixedly attached to the second rigid duct segment, wherein the first joining segment is configured to contact and maintain the contact with the second joining segment during relative movement between the first rigid duct segment and the second rigid duct segment.

[0042] Optionally, the aircraft assembly further comprises: a first U-shaped joint coupling the first rigid pipe section to the fixture and allowing rotation of the first rigid pipe section relative to the fixture about a first universal joint axis; and a second U-shaped joint coupling the second rigid pipe section to the fixture and allowing rotation of the second rigid pipe section relative to the fixture about a second universal joint axis, wherein the second universal joint axis is perpendicular to the first universal joint axis.

[0043] Optionally, the securing device comprises a ball and socket joint; the ball and socket joint comprises a ball located in a socket; a first U-shaped joint couples the first rigid pipe section to the ball; and a second U-shaped joint couples the second rigid pipe section to the ball.

[0044] Optionally, the flexible conduit section comprises a bellows conduit.

[0045] A fifth aspect of the invention provides an aircraft wing comprising the aircraft assembly of the fourth aspect.

[0046] A sixth aspect of the present invention provides an aircraft comprising the aircraft wing of the fifth aspect.

[0047] Features of any of the various aspects of the invention may be combined. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] Embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0049] Figure 1 An aircraft is shown;

[0050] Figure 2 It is a cross-section of the wing box of the starboard wing;

[0051] Figure 3 The wing box extending along the wing is shown;

[0052] Figure 4 The ribs are shown;

[0053] Figure 5 A first example of an aircraft assembly is shown;

[0054] Figure 6 A detailed view of a spacer device of a first example is shown;

[0055] Figure 7 A perspective view of a first example is shown;

[0056] Figure 8 A second example of an aircraft assembly is shown;

[0057] Fig. 9A cross section of an aircraft assembly of a second example is shown;

[0058] Fig.10 Shows Fig. 9 A detailed view of an aircraft assembly of a second example shown in;

[0059] Fig.11 A third example of an aircraft assembly is shown;

[0060] Fig.12 A cross section of an aircraft assembly of a third example is shown;

[0061] Fig.13 A first example of a fuel conduit extending through a series of ribs of an aircraft wing is shown;

[0062] Fig.14 A second example of a fuel conduit extending through a series of ribs of an aircraft wing is shown;

[0063] Fig.15 shows a cross-sectional view of another example of an aircraft assembly viewed from the side;

[0064] Fig.16 Shows the Fig.15 Observed from the same side Fig.15 An assembly in which certain parts are removed;

[0065] Fig.17 yes Fig.15 isometric views of certain parts of the assembly;

[0066] Fig.18 Shown from above Fig.15 An assembly of which certain parts are removed; and

[0067] Fig.19 yes Fig.15 Isometric view of some parts of the assembly. DETAILED DESCRIPTION

[0068] Figure 1 An aircraft 1 is shown having a port wing 2 and a starboard wing 3. Each wing has a cantilever structure having a length extending from a root to a tip (eg, Figure 3 ), the root being joined to the aircraft fuselage 4. The wings 2, 3 are similar in construction and will therefore only be referred to. Figure 2 and Figure 3 The starboard wing 3 is described in detail.

[0069] The main structural element of the wing 3 is the wing box 20, which can be composed of Figure 22 and the front and rear spar 6, 7 are formed. The covers 21, 22 and the spars 6, 7 can each be formed by a carbon fiber reinforced polymer (CFRP) laminate component. Each cover 21, 22 includes a panel assembly and can have a curved aerodynamic outer surface (e.g., an upper surface of the upper cover 21 and a lower surface of the lower cover 22), over which air flows during flight of the aircraft 1. Each cover 21, 22 has an inner surface that carries a series of reinforcements 8 extending in the span direction 42 (only some of the reinforcements 8 are marked to improve the clarity of the drawing). Each reinforcement 8 is joined to one cover 21, 22, but not to another cover.

[0070] It will be appreciated that any number of stiffeners 8 may be applied across the chord of the wing 3, but for clarity, Figure 2 and Figure 3 Only five reinforcement members are shown coupled to each cover member 21 , 22 .

[0071] The wing box 20 may have a plurality of transverse ribs, each of which is joined to the covers 21, 22 and the spars 6, 7. The ribs 10 may include an innermost inboard rib 10a located at the root of the wing box 20, an outermost rib 10c located at the tip of the wing box 20, and one or more mid-span ribs 10b located between the innermost rib 10a and the outermost rib 10c. The innermost rib 10a may be an attachment rib that forms the root of the wing box 20 and is joined to the center wing box 18 within the body of the fuselage 4. Each rib 10a, 10b, 10c may connect the upper cover 21 to the lower cover 22. The reinforcement 8 may pass through a rib recess (not shown) in the rib 10b.

[0072] The aperture 11 is formed in one or more of the ribs 10, such as Figure 4 The duct assemblies 30a, 30b extend through the aperture 11 such that the longitudinal axis 12a of the duct assemblies 30a, 30b extends through the aperture 11. The duct assemblies 30a, 30b include a first rigid duct section 31 and a second rigid duct section 32 extending on either side of the plane of the rib 10. Figure 5 and Figure 6 The example shown in FIG. 1 includes an outer conduit assembly 30a enclosing an inner conduit assembly 30b, but it will be appreciated that in alternative examples (such as described below) Figures 15 to 19 In another example of ), there may be a single pipe assembly 30a, 30b (ie, a single-wall pipe assembly).

[0073] The first rigid pipe section 31 and the second rigid pipe section 32 may include or be formed of metal, such as stainless steel. The first rigid pipe section 31 and the second rigid pipe section 32 may have a constant thickness and diameter.

[0074] The flexible duct sections 33 extend between the first rigid duct section 31 and the second rigid duct section 32 of each duct assembly 30a, 30b, wherein each flexible duct section 33 is located at the plane of the rib 10 such that at least a portion of each flexible duct section 33 extends on either side of the plane of the rib 10. By ensuring that the flexible duct sections 33 are located at the plane of the rib 10, any relative bending of the second duct section 32 with respect to the first duct section 31 occurs on either side of the plane of the rib 10.

[0075] The flexible conduit section 33 may be a bellows conduit or other suitable device for absorbing movement in the conduit assemblies 30a, 30b.

[0076] The flexible pipe section 33 of the outer pipe assembly 30a can be integrally formed with the corresponding first and second rigid pipe sections 31, 32 of the outer pipe assembly 30a. The flexible pipe section 33 of the inner pipe assembly 30b can be integrally formed with the corresponding first and second rigid pipe sections 31, 32 of the inner pipe assembly 30b. In other words, the outer pipe assembly 30a and the inner pipe assembly 30b can be continuous on the rib 10 and there is no detachable coupling.

[0077] The flexible pipe section 33 may be formed of metal, such as stainless steel. The flexible pipe section 33 may be welded to the corresponding first and second rigid pipe sections 31 and 32. The flexible pipe section 33 may be a bellows device including a series of undulations, such as Figure 5 As shown in . The undulations may have a constant wall thickness. Alternatively, the flexible conduit 33 may be a braided conduit arrangement.

[0078] Each flexible duct segment 33 contributes to the relative moment between the corresponding first rigid duct segment 31 and the second rigid duct segment 32 to which they are connected. The movement can be axial and / or rotational. In this way, the load transfer between the outer duct assembly 30a and the rib 10 is reduced. For example, if the outer duct assembly 30a includes a continuous rigid duct segment (not shown), the load on the outer duct assembly 30a caused by the torsion and / or bending of the wing 3 can be transferred from the outer duct assembly 30a to the rib 10, and thus additional reinforcement of the rib 10 is required. In addition, in a double-walled duct having an outer duct assembly 30a and an inner duct assembly 30b, in the case where the outer duct assembly 30a includes a flexible duct segment 33 and the inner duct assembly 30b includes a continuous rigid duct segment (not shown), the inner duct assembly 30b will resist bending and thereby collide with the outer duct assembly 30a, thereby transferring undesirable loads to the rib 10.

[0079] In the present device, load transfer is reduced or alleviated by providing a flexible pipe section 33 for relative movement between the first rigid pipe section 31 and the second rigid pipe section 32 .

[0080] One of the duct segments 31, 32, 33 of the outer duct assembly 30a is axially fixed relative to the rib 10 by a fixing device 25 so as to prevent accidental movement of the duct assembly 30a along the wing box 20. In particular, the fixing device 25 may include a sleeve 26 fixedly attached to the outer surface of the outer duct assembly 30a. The sleeve 26 of the fixing device 25 extends over at least a portion of the duct assembly 30a so as to overlap a portion of each of the first rigid duct segment 31 and the second rigid duct segment 32. The fixing device 25 may be located at the plane of the rib 10.

[0081] The fixing device 25 may comprise a substantially non-conductive material, for example, a non-conductive polymer material. This helps to isolate the pipe components 30a, 30b from the rib 10 so that no metal-to-metal contact is formed. This helps to mitigate the effects of lightning strikes.

[0082] exist Figures 5 to 7 In the example shown in FIG, the first rigid pipe section 31 of the outer pipe assembly 30a is fixed relative to the rib 10, and the second rigid pipe section 32 and the flexible pipe section 33 of the outer pipe assembly 30a are movable relative to the rib 10. Alternatively, the second rigid pipe section 32 or the flexible pipe section 33 of the outer pipe assembly 30a may be fixed relative to the rib 10.

[0083] To accommodate relative movement between the rigid pipe sections 31 , 32 , the sleeve 26 may be formed from a first sleeve portion 26 i and a second sleeve portion 26 j .

[0084] To secure one of the duct segments 31, 32, 33 of the outer duct assembly 30a to the rib 10, the securing device 25 comprises a flange 28 secured to the rib 10 by one or more fasteners 19. It will be appreciated that the rib 10 and the securing device 25 may be integrally formed.

[0085] In order to ensure that the outer pipe assembly 30a maintains a substantially fixed distance from the rib 10 and thereby avoids impacts on the rib 10 and in particular the orifice 11 of the rib 10, the fixing device 25 may include a spacing device 40. An example of such a spacing device 40 is shown in Figure 5 and Figure 6 Shown in.

[0086] The spacer 40 may include a first engagement segment 41 fixedly attached to the first rigid pipe segment 31 of the outer pipe assembly 30a, and a second engagement segment 42 fixedly attached to the second rigid pipe segment 32 of the outer pipe assembly 30a (e.g., via the sleeve portions 26i, 26j). The first engagement segment 41 and the second engagement segment 42 overlap at the plane of the rib 10. The first engagement segment 41 is configured to contact the second engagement segment 42 and maintain contact between the first engagement segment 41 and the second engagement segment 42 during relative movement (e.g., axial movement and / or rotational movement) between the first rigid pipe segment 31 and the second rigid pipe segment 32.

[0087] Figure 6 A close-up view of the spacer 40 is shown, wherein when Figure 6 When viewed in cross section in FIG. 4 , the first engagement section 41 comprises a straight profile 41 a and when viewed in cross section in FIG. Figure 6 When viewed in cross-section in FIG. 1 , the second engagement segment 42 includes a curved (spherical) profile 42a that contacts the straight profile 41a of the first engagement segment 41. A bearing surface is defined between the first engagement segment 41 and the second engagement segment 42 to facilitate relative axial and / or relative rotational movement between the first rigid pipe segment 31 and the second rigid pipe segment 32 while maintaining a gap distance between the second rigid pipe segment 32 of the outer pipe assembly 30a and the fixture 25.

[0088] The second engagement segment 42 can facilitate rotation of the second rigid pipe segment 32 relative to the first rigid pipe segment 31 while preventing collision between the second rigid pipe segment 32 and the fixture 25 when the curved profile 42a of the second engagement segment 42 contacts the straight profile 41a of the first engagement segment 41 .

[0089] In some examples, the fixture 25 may be arranged such that the outer pipe assembly 30a is rotatably coupled to the rib 10 via the fixture 25, such as Figure 8 In particular, the outer pipe assembly 30a is substantially axially fixed at the plane of the rib 10, but can rotate about at least one axis.

[0090] The sleeve 26 may include a protruding portion 26a, wherein the protruding portion 26a is arranged to be rotatably coupled to a corresponding recessed portion 27 of the fixture 25. Alternatively, the sleeve 26 may include a recessed portion 27 corresponding to the protruding portion 26a of the fixture 25. The protruding portion 26a and the recessed portion 27 have corresponding curved profiles.

[0091] exist Figures 8 to 10 In this case, the fixing means comprises a ball and socket joint comprising a ball (projection 26a) and a socket fitting 27).

[0092] The socket fitting 27 includes a concave spherical bearing surface forming a socket. The ball 26a includes a convex spherical bearing surface which is received in the socket to engage the concave spherical bearing surface.

[0093] The fixing device 25 limits the movement of the outer pipe assembly 30a relative to the rib 10 in the longitudinal direction and allows the outer pipe assembly 30a to rotate relative to the rib 10. In particular, the protruding portion 26a and the corresponding recessed portion 27 may have a corresponding spherical curved support surface, which forms a spherical support between the protruding portion 26a and the corresponding recessed portion 27 to allow the pipe assembly 30a to rotate relative to the rib 10. For example, Figure 8 As shown in the figure, the spherical bearing between the protruding portion 26a and the recessed portion 27 allows the pipe components 30a, 30b to rotate relative to the rib 10 about the three vertical axes 12a, 12b, 12c. The spherical bearing surfaces can slide relative to each other to allow such rotation of the pipe components. The rotation of the pipe component 30a via the above-mentioned bearing surfaces between the protruding portion 26a and the recessed portion 27 can supplement the gap distance between the second rigid pipe section 32 of the outer pipe component 30a and the fixing device 25 provided by the spacer 40.

[0094] In addition to enabling the duct assembly to rotate, the spherical bearing surface also performs the function of limiting the movement of the duct assembly relative to the rib 10 in the longitudinal direction due to its spherical shape. Thus, the protrusion 26a acts as a stop member configured to engage with the fixture 25 to limit the movement of the duct assembly 30a, 30b relative to the wing structure in the longitudinal direction. More specifically, in Figure 6In the view of FIG. 2 , the right side of the protruding portion 26a serves as a first stop feature configured to engage with the first portion of the fixture (the right side of the recess 27) to limit the rightward movement of the pipe assembly. Similarly, the left side of the protruding portion 26a serves as a second stop feature configured to engage with the second portion of the fixture (the left side of the recess 27) to limit the leftward movement of the pipe assembly.

[0095] Depending on the fit between the bearing surfaces, a certain amount of play may be allowed in the longitudinal direction. The fixture 25 may be configured to restrict movement of at least a portion of the duct assembly relative to the wing structure in the longitudinal direction with a play of no more than 10 mm, or a play of no more than 5 mm, or a play of no more than 2 mm, or a play of no more than 1 mm.

[0096] The rotation of the duct assemblies 30a, 30b relative to the rib 10 allows to take into account the loads acting on the wing 3. In particular, if the distance of the outer duct assembly 30a from the edge of the aperture 11 is not maintained by the fixing means 25, the bending of the wing 3 may cause the outer duct assembly 30a to collide with the edge of the aperture 11. If the duct assembly is fixed to the rib 10, the torsion and / or bending of the wing 3 may cause significant loads to be transmitted from the duct assembly 30a to the rib 10, and thus require additional reinforcement of the rib 10.

[0097] By allowing the duct assembly 30a to rotate in the plane of the rib 10 about the longitudinal axis 12a of the duct assembly 30a and / or about one or more of the vertical axes 12b, 12c, loads transmitted from the duct assembly 30a due to twisting and / or bending of the wing 3 are reduced or mitigated.

[0098] At the same time, by restricting movement of the duct assembly 30a along its longitudinal axis 12a, the duct assembly 30a is prevented from sliding freely through the wing box 20.

[0099] The outer pipe assembly 30a and the inner pipe assembly 30b can be configured to transport fuel, such as a petroleum-based fuel, such as kerosene or hydrogen fuel. Although it will be understood that the assembly can include a single pipe assembly 30a, 30b, it is particularly advantageous to provide a double-walled pipe assembly having an outer pipe assembly 30a and an inner pipe assembly 30b when transporting cryogenic fuels, such as hydrogen.

[0100] In particular, inner tube assembly 30b may be configured to transport hydrogen fuel, wherein the space defined between outer tube assembly 30a and inner tube assembly 30b provides a thermal barrier between the hydrogen fuel and the temperature in wing box 20, thereby reducing heat transfer to keep the hydrogen fuel cool.

[0101] Compared to the temperature around the wing box 20, the cryogenic temperatures required for storing hydrogen fuel may cause additional loads on the outer and inner duct assemblies 30a, 30b, which may be reduced or mitigated by the fixing device 25. In particular, the cryogenic temperatures may cause the duct assemblies 30a, 30b to shrink. If the duct assemblies 30a, 30b are fixed to the rib 10, these loads may be transferred to the rib 10, and thus additional reinforcement of the rib 10 may be required.

[0102] The hydrogen fuel may be a gaseous hydrogen fuel or a liquid hydrogen fuel. In an example where the hydrogen fuel is a gaseous hydrogen fuel, the space between the outer pipe assembly 30a and the inner pipe assembly 30b may include an inert gas, such as nitrogen. The inert gas may have a high concentration (e.g., 98% or 99%) to prevent any reaction of gaseous hydrogen with oxygen. In an example where the hydrogen fuel is a liquid hydrogen fuel, the space between the outer pipe assembly 30a and the inner pipe assembly 30b may include a vacuum. The vacuum reduces heat transfer between the inner pipe assembly 30a and the outer pipe assembly 30b.

[0103] The protruding portion 26a may be solid, or the thermal insulation between the outer duct assembly 30a and the rib 10 may be further improved by making the protruding portion 26a hollow.

[0104] exist Figure 8 In the example shown in , the flanges 28 each extend around a semicircle of the orifice 11 so as to enclose the pipe components 30a, 30b, and the flanges 28 are engaged by fasteners 19a. However, it will be understood that the flanges 28 may be of any suitable configuration. Figure 7 In the example shown in , a single flange 28 extends around the entire circumference of the pipe assembly 30a, 30b. In some examples, the flange may extend around only a portion of the circumference of the pipe assembly 30a, 30b.

[0105] like Figure 8 As shown in , the flange 28 may be located on a single side of the rib 10, wherein the recessed portion 27 of the fixing device 25 is integrally formed. In an alternative example, the flange may be attached to both sides of the rib 10, such that the recessed portion 27 is formed by two or more sections.

[0106] Fig. 9 and Fig.10 An example is shown in which the fixing arrangement 25 includes a protruding portion 26a configured to engage with a recessed portion 27 and a spacer 40. As will be appreciated, rotation of the duct assembly 30a via the bearing surface between the protruding portion 26a and the recessed portion 27 can supplement the movement provided by the flexible portion 33 of the duct assemblies 30a, 30b and the gap distance achieved by the spacer 40.

[0107] although Figures 5 to 10 The example shown in FIG. 1 provides for rotation of the duct assemblies 30a, 30b about three vertical axes 12a, 12b, 12c, but it will be appreciated that other examples may provide for rotation about one or two vertical axes 12a, 12b, 12c.

[0108] Fig.11 and Fig.12 An example is shown in which the sleeve 26 has a protruding portion 26a of cylindrical shape, wherein the recessed portion 27 has a corresponding profile, so that the outer duct assembly 30a can rotate about the longitudinal axis 12a of the duct assembly 30a, but is substantially prevented from rotating about the transverse axes 12b, 12c parallel to the plane of the rib 10. This allows to reduce or mitigate the loads due to the torsion of the wing 3, which loads might otherwise be transmitted to the duct assembly 30a.

[0109] Fig.11 and Fig.12 The bearing surfaces in each have a generally cylindrical shape that allows the pipe assembly to rotate relative to the rib about a longitudinal axis 12a extending in the longitudinal direction. The generally cylindrical shape of the bearing surfaces also limits the rotation of the pipe assembly relative to the rib about two perpendicular axes 12b, 12c, wherein the two perpendicular axes are perpendicular to each other and to the longitudinal axis 12a.

[0110] As in Fig. 9 and Fig.10 In the embodiment (having a spherical support portion), Fig.11 and Fig.12 The bearing surface in is also shaped to provide a stop feature that limits movement of at least a portion of the duct assembly relative to the rib 10 in the longitudinal direction.

[0111] In this example, it will be appreciated that the flexible portion 33 still allows for some relative movement between the first rigid pipe section 31 and the second rigid pipe section 32 .

[0112] The wing 3 may include a plurality of ribs 10a, 10b, 10c in the wing box 20, such as Figure 3 Each rib may comprise a corresponding flexible duct section 33 located at the plane of the rib 10b, wherein the first duct section 31 and the second duct section 32 extend on either side of the plane of the rib 10b. Fig.13 An example is shown in which a flexible duct section 33 is located at each rib 10 in the wing box 20. Similarly, a fixing device 25 may be located at each rib 10.

[0113] In some examples, it may not be necessary to provide a flexible duct section 33 at each rib 10. For example, the size of the orifice 11 and the expected loads on the duct assemblies 30a, 30b may be such that a flexible duct section 33 may be located at the plane of the first set of ribs 10i, while the second set of ribs 10j may not have a flexible duct section 33 at the plane of each rib 10. At least some of the ribs 10 in the second set of ribs 10j may be located between ribs 10 in the first set of ribs 10i, such as Fig.14 Similarly, the fixing means 25 may be located at the plane of the first set of ribs 10i instead of at the plane of the second set of ribs 10j.

[0114] Fig.15 The aircraft assembly shown in FIG. 5 includes: an aircraft structure 50; and a duct assembly coupled to the aircraft structure 50. The aircraft structure 50 may be a wing rib, a fuselage frame, or any other aircraft structure.

[0115] The pipe assembly includes a first rigid pipe section 51, a second rigid pipe section 52 and a flexible pipe section 53 (in this case a bellows) extending between the first and second rigid pipe sections. The flexible pipe section 53 is configured to allow relative movement between the first and second rigid pipe sections 51, 52.

[0116] Unlike the previous example, Fig.15 The pipe assembly is single-walled rather than double-walled. In other embodiments, Fig.15 The pipe assembly can be replaced by a double-walled pipe device as in the previous embodiment.

[0117] The fixture 54 couples the duct assemblies 51, 52, 53 to the aircraft structure 50. The fixture 54 comprises a ball and socket joint including a ball 55 and a socket fitting 56. The socket fitting 56 comprises a flange 59 which is attached to the aircraft structure 50 by fasteners (not shown).

[0118] The socket fitting 56 includes a concave spherical bearing surface 57 forming a socket. The ball 55 includes a convex spherical bearing surface 58 received in the socket, thereby engaging the concave spherical bearing surface 57. Fig.17 As shown in FIG. , the balls 55 form a continuous ring around the pipe assembly.

[0119] The rigid pipe sections 51, 52 are connected to the ball 55 by a universal joint arrangement, which includes a universal joint arrangement such as Fig.16 The first U-joint 60 shown most clearly from the side and the Fig.18 The same second U-joint 70 is shown most clearly from above in FIG.

[0120] Fig.15and Fig.16 is a cross-sectional side view showing the first U-shaped joint 60 that couples the first rigid pipe section 51 to the ball 55. Fig.15 As shown in FIG. 1 , the first U-joint 60 includes a pair of U-joint arms 63, 64 with pins 65, 66 located on a vertical first universal joint axis 61, and each of the pair of U-joint arms 63, 64 forms a corresponding rotational joint with the ball 55. The rotational joint allows the first rigid pipe section 51 to rotate relative to the ball 55 about the vertical first universal joint axis 61. Fig.16 As shown in FIG. 5 , the first cardan axis 61 is perpendicular to the longitudinal axis 62 of the first rigid pipe section 51 .

[0121] Fig.18 7 is a view from above showing the second U-joint 70, which couples the second rigid pipe section 52 to the ball 55. The second U-joint 70 comprises a pair of U-joint arms 73, 74 with pins 75, 76 located on a horizontal second universal joint axis 71, each forming a respective rotational joint with the ball 55. These rotational joints are Fig.15 are not visible in the image because they are outside the plane of the cross section, but they are Fig.15 The swivel joint allows the second rigid pipe section 52 to rotate relative to the ball 55 about the second universal joint axis 71. The second universal joint axis 71 is perpendicular to the longitudinal axis 72 of the second rigid pipe section 52 and is also perpendicular to the first universal joint axis 61.

[0122] The gimbal joint arrangement allows each rigid pipe section to rotate relative to the other pipe section about a respective gimbal axis 61, 71. The bellows pipe 53 is configured to allow such relative rotation between the first rigid pipe section 51 and the second rigid pipe section 52.

[0123] Now we will compare and contrast Fig. 9 and Fig.15 Both embodiments provide a certain degree of freedom for the rigid duct section relative to the aircraft structure, thereby preventing the bending moment from the rigid duct section from acting on the aircraft structure.

[0124] exist Fig. 9 In the embodiment, the sliding joint between the first joint section 41 and the second joint section 42 in combination with the bellows 33 allows axial translation of the second rigid pipe section 32 relative to the first rigid pipe section 31. Fig.15In the embodiment of the present invention, the universal joint prevents such relative axial translation of the second rigid pipe section 52. This feature of the universal joint can be beneficial because it avoids collapse or overstretching of the bellows 53. The universal joint also has high durability in resisting axial inertia and vibration.

[0125] exist Fig. 9 and Fig.15 In both embodiments, the bellows conduit may be sufficiently rigid to substantially prevent rotation of either rigid conduit segment relative to the other rigid conduit segment about its longitudinal axis (ie, relative "twist" between the rigid conduit segments).

[0126] exist Fig. 9 and Fig.15 In both embodiments, the ball and socket joint allows rotation of both the first rigid duct section and the second rigid duct section relative to the aircraft structure about three orthogonal axes. This can avoid torsional loads (such as torsional loads caused by wing torsion) acting on the duct system.

[0127] exist Fig. 9 In the embodiment, the spherical profile of the second joint segment 42 allows the second rigid pipe segment 32 to rotate relative to the first rigid pipe segment 31 about a pair of transverse axes orthogonal to the longitudinal axis of the second rigid pipe segment 32. Fig.15 In an embodiment of the present invention, the universal joint device limits this relative rotation about the two universal joint axes. On the other hand, Fig.15 The universal joint arrangement enables the two rigid pipe sections to rotate relative to the ball (in Fig. 9 In the embodiment, a first rigid pipe section 31 is fixed to the ball).

[0128] exist Fig. 9 and Fig.15 In both embodiments, so-called "snaking" of the bellows is avoided while still allowing relative rotation between the rigidly joined sections. Snaking occurs when one of the rigid pipe sections translates transversely to its longitudinal axis relative to the other rigidly joined section and does not rotate. This results in misalignment of the longitudinal axes of the rigid pipe sections and this is ideally avoided.

[0129] In the above-described embodiments of the invention, the duct assembly extends through an aperture in an aircraft structure, such as a rib of a wing or a fuselage frame, and the flexible duct section is located at the plane of the aircraft structure. In other embodiments of the invention, the duct assembly may not extend through an aperture in an aircraft structure and / or may not be located at the plane of the aircraft structure. For example, the duct assembly may extend along the length of a wing spar or wing stringer, and a fixture similar to any of the above-described fixtures may couple the duct assembly to the wing spar or wing stringer.

[0130] When the word "or" appears, this will be understood to mean "and / or" such that the referred items are not necessarily mutually exclusive and can be used in any appropriate combination.

[0131] Although the invention has been described above with reference to one or more preferred embodiments, it will be appreciated that various changes or modifications may be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. An aircraft assembly, comprising: the ribs of the wings; an orifice located in the rib; a duct assembly extending through the aperture, the duct assembly comprising a first rigid duct segment, a second rigid duct segment, and a flexible duct segment between the first rigid duct segment and the second rigid duct segment; and A securing device couples one of the duct segments to the rib, wherein the flexible duct segment is located at the plane of the rib and is configured to allow relative movement between the first and second rigid duct segments.

2. The aircraft assembly according to claim 1, wherein: The first rigid duct section is configured to be fixed relative to the rib, and the second rigid duct section is configured to be movable relative to the rib.

3. An aircraft assembly according to claim 1 or 2, wherein: The fixing device includes a first joining section fixedly attached to the first rigid pipe segment and a second joining section fixedly attached to the second rigid pipe segment, and wherein the first joining section is configured to contact and maintain the contact with the second joining section during relative movement between the first rigid pipe segment and the second rigid pipe segment.

4. The aircraft assembly according to claim 3, wherein: The first engagement section and the second engagement section overlap at the plane of the rib.

5. An aircraft assembly according to claim 3 or 4, wherein: The first engagement segment comprises a planar profile and the second engagement segment comprises a curved profile, wherein the first engagement segment and the second engagement segment are in contact at a bearing surface between the planar profile and the curved profile.

6. An aircraft assembly according to any preceding claim, wherein: The duct assembly is an outer duct assembly, and the aircraft assembly includes an inner duct assembly enclosing the outer duct assembly.

7. The aircraft assembly according to claim 6, wherein: The inner pipe assembly includes a first rigid pipe section, a second rigid pipe section, and a flexible pipe section located between the first rigid pipe section and the second rigid pipe section.

8. An aircraft assembly according to any preceding claim, wherein: The pipe assembly is configured to deliver hydrogen fuel.

9. An aircraft assembly according to claim 8 when dependent on claim 6 or 7, wherein: The inner conduit assembly is configured to deliver hydrogen fuel.

10. An aircraft assembly according to claim 8 or 9, wherein: The hydrogen fuel is liquid hydrogen fuel.

11. An aircraft assembly according to claim 8 or 9, wherein: The hydrogen fuel is gaseous hydrogen.

12. An aircraft assembly according to any preceding claim when dependent on claim 6, wherein: The inner pipe assembly is spaced apart from the outer pipe assembly.

13. An aircraft assembly according to claim 12, wherein: The space between the inner tube assembly and the outer tube assembly includes a vacuum or an inert gas.

14. An aircraft assembly according to any preceding claim, wherein: The securing means comprises a substantially non-conductive material configured to isolate the rib from the conduit assembly, and preferably wherein the material is a polymeric material.

15. An aircraft assembly according to any preceding claim, wherein: The duct assembly is continuous over the rib.

16. An aircraft assembly according to any preceding claim, wherein: The fixing device is configured to restrict movement of at least a portion of the pipe assembly in a longitudinal direction of the pipe assembly and to allow rotation of the pipe assembly relative to the rib.

17. The aircraft assembly of claim 14, wherein: The securing device is configured to allow rotation of the duct assembly relative to the rib about a longitudinal axis extending along the longitudinal direction.

18. An aircraft assembly according to claim 16 or 17, wherein: The securing means is configured to allow rotation of the duct assembly relative to the rib about two perpendicular axes, and preferably about three perpendicular axes.

19. An aircraft assembly according to any one of claims 16 to 18, wherein: The fixture and the rib have corresponding curved surfaces forming a bearing surface between the fixture and the rib to allow rotation of the pipe assembly relative to the rib.

20. The aircraft assembly of claim 19, wherein: The bearing surface is formed by the protruding portion of the fixing device and the recessed portion of the rib.

21. An aircraft assembly according to any preceding claim, wherein: The flexible conduit section comprises a bellows conduit.

22. An aircraft assembly according to any preceding claim, wherein: The fixing device comprises a spherical bearing surface which allows a rotation of one of the pipe segments relative to the rib.

23. An aircraft assembly according to claim 22, wherein: The fixing device comprises a ball and socket joint.

24. An aircraft assembly according to claim 23, wherein: The ball and socket joint includes a ball located in a socket, and one of the pipe segments is coupled to the ball.

25. An aircraft wing comprising an aircraft assembly according to any preceding claim.

26. An aircraft wing according to claim 25, comprising a plurality of aircraft components according to any one of claims 1 to 25.

27. An aircraft comprising an aircraft wing according to claim 25 or 26.

28. An aircraft assembly comprising: Aircraft structure; a duct assembly comprising a first rigid duct segment, a second rigid duct segment, and a flexible duct segment extending between the first rigid duct segment and the second rigid duct segment, wherein the flexible duct segment is configured to allow relative movement between the first rigid duct segment and the second rigid duct segment; and A fixture couples the first rigid duct section to the aircraft structure, the fixture including a spherical bearing surface that allows rotation of the first rigid duct section relative to the aircraft structure.

29. An aircraft assembly according to claim 28, wherein: The flexible pipe section is configured to allow relative translation between the first and second rigid pipe sections in an axial direction, wherein the axial direction is parallel to a longitudinal axis of the first or second rigid pipe section.

30. An aircraft assembly according to claim 29 or 30, wherein: The assembly is configured to allow relative rotation between the first rigid pipe section and the second rigid pipe section about a transverse axis, wherein the transverse axis is perpendicular to a longitudinal axis of the first rigid pipe section.

31. An aircraft assembly according to any one of claims 28 to 30, wherein: The fixing device comprises a ball and socket joint.

32. An aircraft assembly according to claim 31, wherein: The ball and socket joint includes a ball located in a socket, and the first rigid pipe section is coupled to the ball.

33. An aircraft assembly according to any one of claims 28 to 32, further comprising a first joining section fixedly attached to the first rigid duct section and a second joining section fixedly attached to the second rigid duct section, wherein: The first engagement segment is configured to contact the second engagement segment and maintain the contact during relative movement between the first rigid pipe segment and the second rigid pipe segment.

34. An aircraft assembly according to any one of claims 28 to 33, further comprising: a first U-joint coupling the first rigid pipe section to the fixture and allowing rotation of the first rigid pipe section relative to the fixture about a first cardan axis; and a second U-joint coupling the second rigid pipe section to the fixture and allowing rotation of the second rigid pipe section relative to the fixture about a second cardan axis, wherein the second cardan axis is perpendicular to the first cardan axis.

35. An aircraft assembly according to claim 34, wherein: The fixture comprises a ball and socket joint; the ball and socket joint comprises a ball located in a socket; the first U-shaped joint couples the first rigid pipe section to the ball; and the second U-shaped joint couples the second rigid pipe section to the ball.

36. An aircraft assembly according to any one of claims 28 to 35, wherein: The flexible conduit section comprises a bellows conduit.

37. An aircraft wing comprising an aircraft assembly according to any one of claims 28 to 36.

38. An aircraft comprising an aircraft wing according to claim 37.

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