Split Riblet

Abstract

To provide riblets for fixed leading edge (FLE) assemblies. [Solution] The present invention relates to a riblet for a fixed leading edge (FLE) assembly. The riblet includes a first riblet portion having a first rear mounting portion for attaching a first riblet portion to a main wing box assembly, and a first riblet portion having a front mounting portion opposite to the first rear mounting portion. The riblet also includes a second riblet portion having a second rear mounting portion for attaching a second riblet portion to the front mounting portion of the first riblet portion.

Description

Technical Field

[0001] The present invention relates to riblets for a fixed leading edge (FLE) assembly, a fixed leading edge assembly including the riblets, a fixed leading edge, an airfoil structure including the fixed leading edge assembly, an aircraft including the airfoil structure, and a method of assembling the airfoil structure.

Background Art

[0002] Airfoil structures found in various aircraft, spacecraft, and wind turbine applications typically include one or more longitudinal spars and a plurality of transverse ribs, and have a main wing box structure surrounded by a structural cover. A fixed leading edge (FLE) structure and / or a fixed trailing edge (FTE) structure may be attached to such a main wing box structure to form an airfoil shape.

[0003] Increasing production throughput is a common goal of the entire aircraft manufacturing industry to help meet the growing worldwide demand for aircraft, which requires faster aircraft delivery times.

[0004] However, fixed leading edge (FLE) structures currently require a lot of time for assembly and subsequent installation because little pre-assembly can be done on the FLE structure. Further, due to all the systems that need to be installed via the FLE structure, little work can be done on the FLE structure in parallel with other assembly processes.

Summary of the Invention

Problems to be Solved by the Invention

[0005] An object of the present invention is to provide a solution to this problem.

[0006] According to a first aspect of the present invention, a riblet for a fixed leading edge (FLE) assembly is provided, comprising a first riblet portion and a second riblet portion, the first riblet portion comprising a first rear mounting portion for attaching the first riblet portion to a main wing box assembly and a front mounting portion opposite to the first rear mounting portion, and the second riblet portion comprising a second rear mounting portion for attaching the second riblet portion to the front mounting portion of the first riblet portion.

[0007] Advantageously, by providing a riblet having two parts, aircraft assembly personnel can attach the first riblet to the forward (e.g., leading edge) spar of the wing box assembly before attaching and / or assembling the second riblet.

[0008] This allows aircraft assembly personnel to have complete and uninterrupted access to the first riblet section and the corresponding fittings located on the forward spar of the main wing box assembly, thereby improving ease of assembly.

[0009] Furthermore, since the first riblet section is significantly smaller and lighter than the fully fixed leading edge assembly, the two-part configuration of the riblet also makes it easier for the assembly worker to manipulate and align the first riblet section with the forward spar of the main wing box assembly, as may be required during assembly.

[0010] In addition, the two-part riblet configuration also allows work to be performed on the second riblet section parallel to the first riblet section, which is attached to the forward spar of the main wing box assembly, thereby helping to further reduce aircraft assembly time.

[0011] In exemplary embodiments, the front mounting portion of the first riblet and the second rear mounting portion of the second riblet may each be provided with fastener holes, and the riblet may further include at least one fastener extending in the chordwise direction between the fastener holes.

[0012] Please understand that each fastener hole is pre-drilled in the first and second riblet sections.

[0013] The term “pre-drilled” is defined herein to mean that the respective fastener holes are formed in the first and second riblet sections before they are joined together and aligned. In other words, the first and second riblet sections are joined to each other via hole-to-hole joints. Thus, the first and second riblet sections are first joined together and then attached (via at least one fastener) during final assembly.

[0014] Advantageously, using such "hole-to-hole" joints allows the first and second riblet sections to be joined without requiring part-to-part drilling before final assembly, which helps to further improve aircraft assembly time.

[0015] In exemplary embodiments, the forward mounting of the first riblet section and the second rear mounting of the second riblet section may each be provided with a plurality of fastener holes spaced apart in the thickness direction, and the riblet may further be provided with a plurality of fasteners extending in the chord direction between each fastener hole.

[0016] In exemplary embodiments, at least one of the front mounting portion and / or the second rear mounting portion may include an eccentric bush for adjusting the position and / or orientation of the fastener hole relative to the second rear mounting portion and / or the front mounting portion.

[0017] Advantageously, by providing an eccentric bushing, the manufacturer can improve tolerance control in the thickness direction (Z-axis direction) between the first riblet portion and the second riblet portion.

[0018] In an exemplary embodiment, there may be no fastener holes before the first rear mounting portion of the first riblet aligns the first riblet with the main wing box assembly.

[0019] In other words, the first riblet section may be joined to the wing box assembly via a part-to-part connection, which is drilled and assembled before the final assembly.

[0020] Advantageously, the use of an "inter-part" joint between the first riblet section and the forward spar provides manufacturers with improved tolerance control in the thickness direction (Z-axis) and the spanwise direction (X-axis).

[0021] In exemplary embodiments, the first riblet portion may include first and second rearward projections spaced apart in the thickness direction.

[0022] In exemplary embodiments, the first riblet portion may further comprise a first cavity defined between a first rear projection and a second rear projection, the first cavity being configured to accommodate one or more aircraft subsystems.

[0023] One or more aircraft subsystems may be electrical subsystems (e.g., power control systems and / or signal control systems), hydraulic subsystems, hot air bleed subsystems, and / or mechanical subsystems (e.g., drive shafts).

[0024] In exemplary embodiments, the first riblet portion may include a plurality of first rear mounting portions spaced apart in the thickness direction.

[0025] In an exemplary embodiment, the plurality of first rear attachment portions may be located on the same plane.

[0026] Advantageously, by providing the plurality of first rear attachment portions on the same plane, it becomes possible to stack the fixed leading edge assembly in a series of layers, thereby further improving the accessibility for aircraft assembly personnel.

[0027] In an exemplary embodiment, the plurality of first rear attachment portions may be disposed on the first and second rear protrusions.

[0028] In an exemplary embodiment, the second riblet portion may be substantially D-shaped when viewed in the wingspan direction.

[0029] It should be understood that the second riblet portion may alternatively be referred to as a leading edge D-nose portion.

[0030] In an exemplary embodiment, the riblet may further include a second cavity formed between the first riblet portion and the second riblet portion, and the second cavity is configured to receive one or more aircraft subsystems.

[0031] Advantageously, by providing the second cavity formed between the first riblet portion and the second riblet portion, one or more aircraft subsystems received therein can be better isolated from the front (e.g., leading edge) spar of the wing box assembly.

[0032] The one or more aircraft subsystems can be an electrical subsystem (e.g., a power control system and / or a signal control system), a hydraulic subsystem, a hot air bleed subsystem, and / or a mechanical subsystem (e.g., a drive shaft).

[0033] In exemplary embodiments, the riblet may include a joint line that extends through the thickness of the riblet between the first riblet portion and the second riblet portion.

[0034] In exemplary embodiments, the joint line may intersect with the second cavity.

[0035] Advantageously, by positioning the second cavity on the joint line, it becomes easier to position one or more components constituting an aircraft subsystem within the second cavity during assembly, thereby helping to further reduce the aircraft assembly time.

[0036] A second aspect of the present invention is provided, which includes a riblet according to the first aspect of the present invention and a D-nose cover defining the aerodynamic surface of the fixed leading edge assembly, wherein the D-nose cover is attached to the second riblet portion.

[0037] In exemplary embodiments, the fixed leading edge (FLE) assembly may comprise a plurality of riblets arranged at regular intervals along the wingspan in the direction of the fixed leading edge assembly.

[0038] In exemplary embodiments, the D-nose cover does not necessarily have to be directly joined to the first riblet portion.

[0039] Advantageously, leaving the first riblet section unjoined to the D-nose cover provides the fixed leading edge (FLE) assembly with a tolerance gap in the thickness (Z-axis) direction, allowing for vertical adjustment of the position of the first riblet section relative to the second riblet section, which may be necessary to meet aerodynamic requirements and / or to manage the clearance between the D-nose cover of the fixed leading edge (FLE) assembly and the cover of the main wing box assembly.

[0040] In exemplary embodiments, the D-nose cover may include at least one access hole configured to provide access to the riblets.

[0041] According to a third aspect of the present invention, a fixed leading edge (FLE) module is provided, comprising a D-nose cover defining the aerodynamic surface of the FLE module, and a second riblet portion having a second rearward mounting portion for attachment to a front mounting portion of a first riblet portion, wherein the D-nose cover is attached to the second riblet portion.

[0042] In exemplary embodiments, the fixed leading edge module may comprise a plurality of second riblet sections arranged at equal intervals in the wingspan direction along the fixed leading edge module.

[0043] A fourth aspect of the present invention provides an airfoil structure comprising a main wing box assembly having a forward spar and at least one airfoil cover defining the aerodynamic surface of the airfoil structure, and a fixed leading edge (FLE) assembly according to a second aspect of the present invention, wherein the fixed leading edge assembly is attached to the forward spar via a first rearward attachment portion of a first riblet portion.

[0044] In exemplary embodiments, the airfoil cover and the D-nose cover may both form substantially coplanar aerodynamic surfaces.

[0045] In exemplary embodiments, the airfoil cover and the D-nose cover may be joined to each other via a skin joint or a butt joint.

[0046] In exemplary embodiments, the airfoil structure may comprise a plurality of fixed leading-edge assemblies according to a second aspect of the present invention.

[0047] In exemplary embodiments, the airfoil structure may be an aircraft wing.

[0048] According to a fifth aspect of the present invention, an aircraft is provided that includes an airfoil structure according to a fourth aspect of the present invention.

[0049] According to a sixth aspect of the present invention, a method for assembling an airfoil structure according to a fourth aspect of the present invention is provided, which is: a) Align the first rear mounting portion of the first riblet section with the respective mounting fixtures provided on the forward spar of the airfoil structure; b) Perforating at least one hole in the airfoil structure for receiving each fastener, the hole extending through the fastener and through the first rear mounting portion of the first riblet; c) According to the present invention, a fastener can be inserted into at least one hole to attach the first riblet portion to a mounting fixture provided on the front girder. d) After the first riblet section is attached to the front spar, the second rear mounting section of the second riblet section is attached to the front mounting section of the first riblet section.

[0050] Advantageously, the first riblet section can be attached to the forward (e.g., leading edge) spar of the wing box assembly before the second riblet section is attached, so that aircraft assembly personnel are provided with full and uninterrupted access to the first riblet section and the corresponding attachment provided on the forward (e.g., leading edge) spar, which greatly improves the ease of assembly and therefore helps reduce aircraft assembly time.

[0051] Furthermore, in addition to improving accessibility for aircraft assembly personnel, the claimed invention also enables aircraft assembly personnel to perform work on the second riblet section simultaneously while the first riblet section is joined to the forward spar, thereby further reducing aircraft assembly time and thus further improving production throughput.

[0052] It should also be understood that the use of “part-to-part” joining between the first riblet section and the forward spar provides manufacturers with improved tolerance control in the thickness direction (Z-axis) and the wingspan direction (X-axis).

[0053] In an exemplary embodiment, the D-nose cover may be attached to the second riblet section before step d).

[0054] In exemplary embodiments, the forward spar may be provided with a plurality of mounting fixtures spaced apart in the thickness direction, and the method may further include, prior to step c), installing one or more aircraft subsystems in the space defined between the plurality of mounting fixtures provided on the forward spar.

[0055] In exemplary embodiments, the riblet may include a second cavity formed between a first riblet portion and a second riblet portion, and the method may further include a step between step c) and step d) of installing one or more aircraft subsystems in the second cavity.

[0056] According to a seventh aspect of the present invention, a riblet for an airfoil structure is provided, comprising a leading-edge nose portion, a tail portion configured to facilitate attachment of the leading-edge nose portion to a leading-edge spar, and a joining line extending through the thickness of the riblet between the leading-edge nose portion and the tail portion.

[0057] Next, embodiments of the present invention will be described with reference to the accompanying drawings: [Brief explanation of the drawing]

[0058] [Figure 1] Figure 1 is a schematic plan view of an aircraft according to one embodiment of the present invention;

[0059] [Figure 2] Figure 2 is a schematic plan view of the wing of the aircraft shown in Figure 1;

[0060] [Figure 3] Figure 3 is a schematic cross-sectional view of a fixed front edge assembly according to an embodiment of the present invention;

[0061] [Figure 4]Figure 4 is a flowchart showing how to assemble an aircraft wing according to one embodiment of the present invention.

[0062] [Figures 5A-5F] Figures 5A to 5F provide schematic diagrams of the various steps of the method shown in Figure 4. [Modes for carrying out the invention]

[0063] Figure 1 shows an aircraft 10. The aircraft 10 has a fuselage 11 and starboard and port fixed wings 12. An engine 13 is mounted on each wing 12. The aircraft also has a tail (or tail assembly) including starboard and port horizontal stabilizers 14 and a vertical stabilizer 15.

[0064] In the embodiment shown in Figure 1, aircraft 10 is a typical jet passenger transport aircraft, but the present invention is applicable to a wide variety of fixed-wing aircraft types, including commercial, military, passenger, cargo, jet, propeller, and general aircraft, having any number of engines 13 mounted on the wings 12 or fuselage 11.

[0065] A schematic diagram of the wing box assembly 20 of the right wing 12 is shown in Figure 2. The port wing has a similar structure, and therefore only the description of the right wing is provided herein.

[0066] The main wing 12 has a cantilever structure with a length extending in the wingspan direction from the wing root 16 to the wing tip 17, and the wing root 16 is joined to the aircraft fuselage 11. As shown in Figure 1, the main wing 12 has a leading edge 18 and a trailing edge 19. The leading edge 18 is at the front end of the main wing 12, and the trailing edge 19 is at the rear end of the main wing 12. The main wing 12 comprises a wing box assembly 20 and a leading edge and trailing edge assembly (shown in Figure 3).

[0067] The leading-edge and trailing-edge assemblies may include one or more control surfaces (e.g., slats, flaps, ailerons, etc.) for controlling the aircraft 10's movement around its longitudinal and / or transverse axes.

[0068] As shown in Figure 2, the main wing 12 has a wingspan axis (X) extending from the wing root 16 to the wingtip 17, a chord axis (Y) extending from the leading edge 18 to the trailing edge 19, and a thickness axis (Z - shown in Figure 3) extending perpendicular to the chord axis (Y) and the wingspan axis (X).

[0069] The main wing box assembly 20 forms a structural assembly and includes forward spars 21 and aft spars 22 extending in the wingspan direction between the wing root 16 and the wingtip 17, ribs 23 extending in the chord direction between the forward spars 21 and aft spars 22, upper and lower airfoil covers 24 on the upper and lower sides of the main wing box assembly 20, and stringers 30 to which the upper and lower airfoil covers 24 are attached. It should be understood that the upper and lower airfoil covers 24 define the outermost aerodynamic surface of the main wing box assembly 20.

[0070] Each of the forward spar 21 and rear spar 22 may be formed as a C or Z term having an upper flange 25 and a lower flange 26 extending from an upright web 27, and the upper and lower skins 24 of the main wing box assembly 20 may be attached to the flanges 25, 26 of the forward spar 21 and rear spar 22, respectively.

[0071] A schematic cross-sectional view of the fixed leading edge (FLE) assembly 100 of the right main wing 12 is shown in Figure 3.

[0072] The fixed leading edge assemblies of the port wings are structurally similar, and therefore, it should be understood that this specification only provides a description of the right wing fixed leading edge assembly 100.

[0073] While a single fixed leading-edge assembly 100 is shown in Figure 3, it should be understood that in some embodiments, the aircraft wing 12 may have multiple fixed leading-edge assemblies 100 (as shown in Figure 5F) that can be positioned along the leading edge 18 of the aircraft wing 12.

[0074] The fixed leading edge assembly 100 (also called the leading edge “D-nose”) includes a D-nose cover 102 that defines the aerodynamic surface of the fixed leading edge assembly 100, and a plurality of riblets 110 that are arranged at equal intervals in the wingspan direction along the fixed leading edge assembly 100.

[0075] Figure 3 shows a cross-sectional view (or side view) of the fixed leading edge assembly 100, so please note that only one of the aforementioned riblets 110 is visible in Figure 3.

[0076] As shown in Figure 3, the D-nose cover 102 and the upper airfoil cover 24 are positioned substantially coplanar with the upper airfoil cover 24 of the wing box assembly 20, so that the D-nose cover 102 and the upper airfoil cover 24 together form a smooth aerodynamic surface along the negative pressure side of the aircraft wing 12.

[0077] In the illustrated embodiment, the D-nose cover 102 is formed from an aluminum sheet. However, in other embodiments, the D-nose cover 102 may be formed from other suitable materials. For example, in some embodiments, the D-nose cover 102 may be formed from a composite material.

[0078] Referring to the riblet 110, as shown in Figure 3, the riblet 110 is composed of two parts: a first riblet section 120 and a second riblet section 130, which are joined to each other along a joint line (or dividing line) 140 that extends through the thickness of the riblet 110 between the first riblet section 120 and the second riblet section 130.

[0079] It should be understood that the first riblet portion 120 may be alternatively referred to as the "tail portion".

[0080] In the illustrated embodiment, the riblets 110 of the fixed leading edge assembly 100 are formed from a composite material. However, in other embodiments, the riblets 110 may be formed from other suitable materials. For example, in some embodiments, the riblets 110 may be milled from one or more billets of aircraft-grade aluminum alloy.

[0081] As shown in Figure 3, the first riblet section 120 is substantially C-shaped when viewed in the wingspan direction (X-axis) and includes a body 122 and a pair of first and second rear projections 124 and 126 that extend rearward toward the forward spar 21 of the main wing box assembly 20 in the chord direction (Y-axis) away from the body 122.

[0082] The first rear projection 124 and the second rear projection 126 are spaced apart in the thickness (Z-axis) direction, and a first cavity 128 for receiving one or more aircraft subsystems 150 is defined between them.

[0083] One or more aircraft subsystems 150 may be electrical subsystems (e.g., power control systems, signal transmission control systems, etc.), hydraulic subsystems, hot air extraction subsystems, and / or mechanical subsystems (e.g., drive shafts) for operating one or more control surfaces of the aircraft 10, such as slats (not shown).

[0084] The first riblet section 120 also includes a first rearward mounting section for attaching the first riblet section 120 to the forward spar 21 of the main wing box assembly 20.

[0085] In the illustrated embodiment, the first riblet section 120 includes a pair of first rearward mounting sections 121, 123 for attaching the first riblet section 120 (and therefore the fixed leading edge assembly 100) to a pair of corresponding mounting fixtures 30, 32 provided on the forward spar 21 of the main wing box assembly 20. However, it should be understood that in other embodiments, a different number of first rearward mounting sections may be provided.

[0086] As shown in Figure 3, in the illustrated embodiment, a pair of first rear mounting portions 121 and 123 are positioned on the first and second rear projections 124 and 126. Therefore, similar to the first rear projection 124 and the second rear projection 126, the first rear mounting portions 121 and 123 are spaced apart in the thickness (Z-axis) direction such that one of the first rear mounting portions 121 is positioned close to the upper airfoil cover 24, and the other of the first rear mounting portion 123 is positioned close to the lower airfoil cover 24.

[0087] In the illustrated embodiment, the first rear mounting portions 121 and 123 are arranged so that they lie on the same vertical plane. As will be described in more detail later in this application, by providing the first rear mounting portions 121 and 123 on the same vertical plane, the fixed front edge assemblies 100 can be stacked in a series of layers, thereby improving accessibility for assembly personnel.

[0088] The first rear mounting sections 121 and 123 are attached to their respective mounting fixtures 30 and 32 on the forward spar 21 of the wing box assembly 20 via “part-to-part” joints, meaning that the first rear mounting sections 121 and 123 do not have fastener holes, before the first riblet section 120 is aligned with the wing box assembly 20 during the construction of the aircraft wing 12.

[0089] The term “inter-component” joining is well understood in the art and should be understood as referring to a joining method in which two (or more) components, in this case the first riblet portion 120 and the front spar 21, are joined together and drilled before final assembly.

[0090] Advantageously, the use of a so-called "inter-part" joint between the first riblet section 120 and the forward spar 21 provides the manufacturer with improved tolerance control in the thickness direction (Z-axis) and wingspan direction (X-axis) during the assembly of the aircraft wing 12.

[0091] However, it should be understood that in other embodiments, other types of joining, such as "hole-to-hole" joining, may be used.

[0092] Referring further to Figure 3, the first riblet portion 120 also includes a front mounting portion provided on the main body 122 of the first riblet portion 120, on the opposite side from the first rear mounting portion.

[0093] In the illustrated embodiment, the first riblet portion 120 includes a pair of front mounting portions 125, 127 configured to facilitate attachment of the first riblet portion 120 to the second riblet portion 130. However, it should be understood that in other embodiments, a different number of front mounting portions may be provided.

[0094] As shown in Figure 3, similar to the pair of first rear mounting portions 121 and 123, the pair of front mounting portions 125 and 127 are spaced apart in the thickness (Z-axis) direction such that one of the front mounting portions 125 is located close to the upper airfoil cover 24 and the other of the front mounting portion 127 is located close to the lower airfoil cover 24.

[0095] In the illustrated embodiment, the front mounting portions 125 and 127 are spaced apart in the thickness (Z-axis) direction such that the Z-axis positions of the front mounting portions 125 and 127 correspond to the Z-axis positions of the first rear mounting portions 121 and 123. However, it should be understood that in other embodiments, the front mounting portions and the first rear mounting portions may be located at different Z-axis positions.

[0096] Now, considering the second riblet section 130, the second riblet section 130 is substantially D-shaped when viewed in the wingspan direction, and therefore can be alternatively called the "leading edge D-nose section".

[0097] Similar to the first riblet portion 120, the second riblet portion 130 includes a second rear mounting portion configured to facilitate attachment of the second riblet portion 130 to the front mounting portions 125 and 127 of the first riblet portion 120.

[0098] It should be understood that the number of second rear mounting points provided on the second riblet section 130 typically corresponds to the number of front mounting points provided on the first riblet section 120.

[0099] Therefore, in the illustrated embodiment, the second riblet portion 130 comprises a pair of second rear mounting portions 132 and 134 spaced apart in the thickness (Z-axis) direction such that the Z-axis positions of the second rear mounting portions 132 and 134 correspond to the respective Z-axis positions of the front mounting portions 125 and 127. However, it should be understood that in other embodiments, a different number of second rear mounting portions may be provided.

[0100] In the illustrated embodiment, the first riblet portion 120 and the second riblet portion 130 are joined to each other via a series of "hole-to-hole" joints, which means that the front mounting portions 125, 127 (provided on the first riblet portion 120) and the second rear mounting portions 132, 134 (provided on the second riblet portion 130) each have pre-drilled fastener holes.

[0101] The term "hole-to-hole" joining is well understood in the art and refers to a joining of two (or more) components, in this case the first riblet portion 120 and the second riblet portion 130, where fastener holes are formed before the components are joined together. In other words, the first riblet portion 120 and the second riblet portion 130 are joined together for the first time during the final assembly.

[0102] This is different from so-called "inter-part" joining, where two (or more) components are joined together and drilled before final assembly.

[0103] Therefore, by using fastener hole (or hole-to-hole) joining, the respective riblet sections 120 and 130 can be joined without requiring drilling of part-to-part connections before final assembly.

[0104] In the illustrated embodiment, the use of more time-consuming "part-to-part" joining is reserved for "aerodynamically important" areas of the fixed leading edge assembly 100 (such as the joining between the first riblet section 120 and the forward spar 21, where the upper and lower airfoil covers 24 and the D-nose cover 102 require high flushness), while the faster "hole-to-hole" joining is utilized for "aerodynamically unimportant" areas of the fixed leading edge assembly 100.

[0105] In this way, it is possible to improve the aircraft assembly time (and consequently the production throughput) while maintaining excellent tolerance control in the aerodynamically important areas of the aircraft 10.

[0106] As shown in Figure 3, the fastener holes provided in the first riblet portion 120 and the second riblet portion 130 are arranged so that when the first riblet portion 120 and the second riblet portion 130 are joined together, they extend in the chord direction (Y axis) and form a channel that extends across the joint line 140.

[0107] Each channel formed by the fastener holes of the front and second rear mounting portions is configured to receive a corresponding fastener (not shown) that extends in the chord direction across the joining line 140 between the respective fastener holes, thereby joining the first riblet portion 120 and the second riblet portion 130.

[0108] In some examples, the first riblet portion 120 provided on the second riblet portion 130 or the front mounting portions 125, 127 provided on the second rear mounting portions 132, 134 may also be pre-attached with restraining nuts (not shown) so that only fasteners (e.g., bolts) need to be attached to their respective channels during assembly.

[0109] In the illustrated embodiment, the riblet 110 comprises a pair of front mounting sections 125, 127 and a second rear mounting section 132, 134, and thus a pair of fasteners (e.g., bolts) extending in the chord direction between each fastener hole are provided. However, it should be understood that in other embodiments, a different number of fasteners may be provided.

[0110] Furthermore, it should be understood that in some embodiments, the front mounting portion and / or the second rear mounting portion may be provided with an eccentric bush (not shown) configured to adjust the position and / or orientation of the fastener holes relative to the second rear mounting portion and / or the front mounting portion. It should be understood that rotating the eccentric bush adjusts the position of the fastener holes in the thickness (Z) direction and the wingspan (X) direction.

[0111] Advantageously, by providing an eccentric bushing, manufacturers can obtain improved tolerance control in the thickness direction (Z-axis direction) between the first riblet portion 120 and the second riblet portion 130. Furthermore, since the use of an eccentric bushing can be implemented without requiring part-to-part drilling before final assembly, the above-mentioned improvement in tolerance control can also be achieved without adversely impacting assembly time.

[0112] However, it should be understood that in other embodiments, the fastener holes associated with the front and / or second rear mounting portions may alternatively be in a fixed position.

[0113] Referring further to Figure 3, in the illustrated embodiment, the riblet 110 further comprises a second cavity 142 spaced apart from the first cavity 128 in the chord direction (Y-axis) for receiving one or more further aircraft subsystems 152.

[0114] As described above, one or more further aircraft subsystems 152 may be electrical subsystems (e.g., power control systems, signal transmission control systems, etc.), hydraulic subsystems, hot air extraction subsystems, and / or mechanical subsystems (e.g., drive shafts) for operating one or more control surfaces of the aircraft 10, such as slats (not shown).

[0115] As shown in Figure 3, the second cavity 142 is formed between the first riblet section 120 and the second riblet section 130 and is intersected by a joint line 140 that allows for easier placement of one or more components constituting a further aircraft subsystem 152 within the second cavity during the assembly of the aircraft wing 12.

[0116] In other words, the first portion of the second cavity 142 is defined by a recess provided in the first riblet portion 120, and the second portion of the second cavity 142 is defined by a recess provided in the second riblet portion 130.

[0117] However, it should be understood that in other embodiments, the second cavity 142 may instead be entirely defined by a recess (or notch) provided in the first riblet portion 120, or by a recess (or notch) provided in the second riblet portion 130. In other words, the second cavity 142 may be entirely located within the first riblet portion 120 or the second riblet portion 130.

[0118] Furthermore, it should be understood that in some embodiments, one or more additional cavities may be provided around the riblet 110. Such cavities may be provided along the first riblet portion 120, the second riblet portion 130, and / or along the joint line 140 extending between the first riblet portion 120 and the second riblet portion 130.

[0119] Referring now to the D-nose cover 102, as shown in Figure 3, the D-nose cover 102 is attached to the second riblet section 120 at the first end and to the upper airfoil cover 24 at the second end via a skin or butt joint section 104.

[0120] However, in the illustrated embodiment, the D-nose cover 102 is not directly joined to the first riblet portion 120.

[0121] In particular, it was found that leaving the first riblet portion 120 unjoined to the D-nose cover 102 provides a tolerance gap in the thickness (Z-axis) direction to the fixed leading edge assembly 100, allowing for vertical adjustment of the position of the first riblet portion 120 relative to the second riblet portion 130, which may be necessary to satisfy aerodynamic requirements and / or to manage the gap between the D-nose cover 102 of the fixed leading edge assembly 100 and the upper airfoil cover 24 of the right main wing 12.

[0122] In the illustrated embodiment, the D-nose cover 102 also includes an access hole 106 located in a portion of the D-nose cover 102 adjacent to the lower airfoil cover 24, providing assembly or crushing maintenance personnel with access to the inside of the fixed leading edge assembly 100. Specifically, during the assembly process of joining the fixed leading edge assembly 100 to the main wing box assembly 20, when the access panel 106a (shown detached from the D-nose cover 102 in Figure 3) is removed, the access hole 106 is exposed, thereby allowing access for adjustment, drilling, fastening, and cleaning tools to be introduced into areas around one or more of the riblets 110.

[0123] Next, a method 200 for assembling an aircraft wing according to an embodiment of the present invention will be described with reference to Figures 4 and 5.

[0124] During the first step 201 of the method 200 described above, the first riblet section 120 is joined with the forward spar 21 of the wing box assembly 20 such that the first rear mounting sections 121 and 123 provided on the first riblet section 120 are aligned with the respective mounting fixtures 30 and 32 provided on the forward spar 21.

[0125] As shown in Figure 5A, during step 201, the first riblet section 120 is not attached to the second riblet section 130 (nor is the first riblet section 120 attached to the D-nose cover 102), which makes it easier for the assembly worker to move the first riblet section 120 to the desired position.

[0126] During step 201, each first riblet section 120 may be individually aligned with the respective mounting fixtures 30, 32 provided on the forward spar 21 of the main wing box assembly 20, or, as shown in Figure 5A, in some embodiments, the first riblet sections 120 may be fixed to the jig 170 before step 201, thereby allowing multiple first riblet sections 120 to be aligned simultaneously with the corresponding mounting fixtures 30, 32 provided on the forward spar 21.

[0127] Referring now to Figure 5B, once the first rear mounting portions 121 and 123 of the first riblet portion 120 are properly aligned with the respective mounting fixtures 30 and 32 provided on the forward spar 21, a series of fastening holes (not shown) are drilled in the aircraft wing 12 during step 202.

[0128] Each fastener hole (not shown) extends through one of the mounting fixtures 30, 32 provided on the forward spar 21, and through corresponding first rear mounting sections 121, 123 (provided on the first riblet section 120) aligned with the mounting fixtures 30, 32, allowing one or more fasteners to be received in the fastener holes, thereby securing the first riblet section 120 to the forward spar 21 of the main wing box assembly 20.

[0129] In the illustrated embodiment, each first riblet section 120 comprises a pair of first rearward mounting sections 121, 123 that align with a pair of corresponding mounting fixtures 30, 32 provided on the forward spar 21 of the main wing box assembly 20.

[0130] Accordingly, in the illustrated embodiment, during step 202, a pair of fastening holes (not shown) are drilled in the aircraft wing 12 for each of the first riblet portions 120, the first riblet portion extending through one of the respective fasteners 30 and through a corresponding first rear fastening portion 121 to which the first fastener of the fastener 30 is aligned, and the second fastening hole extending through the other of the respective fasteners 32 and through a corresponding first rear fastening portion 123 to which the second fastener of the fastener is aligned.

[0131] However, in embodiments featuring a different number of first rear mounting portions and / or fixtures, it should be understood that a different number of fastener holes (not shown) may be drilled into each of the first riblet portions 120.

[0132] In the embodiment shown in Figure 3, each fastener hole (not shown) is drilled so as to extend in the wingspan direction (X-axis direction) relative to the aircraft wing 12. However, in other embodiments, the fastener holes (not shown) may be drilled in different orientations.

[0133] Referring here to Figure 5C, once each fastener hole (not shown) is drilled within the first rear mounting sections 121, 123 and the corresponding mounting fixtures 30, 32, the first riblet section 120 is prevented from coming into contact with (or being removed from) the front spar 21 during step 203, so that each fastener hole (not shown) can be cleaned in preparation for final assembly.

[0134] Optionally, if the first riblet section 120 is removed during step 203, one or more aircraft subsystems 150 may be installed in the space 34 defined between a pair of mounting fixtures 30, 32 provided on the forward spar 21.

[0135] As described above, one or more aircraft subsystems 150 may be electrical subsystems (e.g., power control systems, signal transmission control systems, etc.), hydraulic subsystems, hot air extraction subsystems, and / or mechanical subsystems (e.g., drive shafts) for operating one or more control surfaces of the aircraft 10, such as slats (not shown).

[0136] Referring now to Figure 5D, once each fastener hole (not shown) is cleaned and one or more aircraft subsystems 150 are optionally installed in the space 34 provided between their respective mounting fixtures 30, 32, the first riblet section 120 is returned to contact the forward spar 21 so that the first rear mounting sections 121, 123 are realigned with the corresponding mounting fixtures 30, 32.

[0137] Next, during step 204, one or more fasteners (e.g., bolts) are inserted into fastener holes drilled in the aircraft wing 12 during step 202 to attach the first riblet portion 120 to the forward spar 21 of the wing box assembly 20, thereby securing the first riblet portion 120 to the aircraft wing 12.

[0138] As shown in Figure 3, when the first riblet section 120 is joined to the forward spar 21, one or more aircraft subsystems 150 are enclosed by a first cavity 128 defined between the respective rear projections 124, 126 of the first riblet section 120, and it should be understood that one or more aircraft subsystems 150 are received within the space defined between the first cavity 128 and the forward spar web 27.

[0139] Furthermore, in this invention, since the first riblet portion 120 can be attached to the forward (e.g., leading edge) spar 21 prior to the attachment of the second riblet portion 130, aircraft assembly personnel are provided with complete and uninterrupted access to the first riblet portion 120 and the corresponding attachments 30, 32 provided on the forward (e.g., leading edge) spar 21, which greatly improves the ease of assembly and therefore helps to reduce aircraft assembly time.

[0140] Referring now to Figure 5E, once the first riblet section 120 is fixed to the forward spar 21 of the main wing box assembly 20, one or more further aircraft subsystems 152 can be installed in recesses provided in the first riblet section 120 that define the first portion of the second cavity 142 during step 205.

[0141] As described above, one or more further aircraft subsystems 152 may be electrical subsystems (e.g., power control systems, signal transmission control systems, etc.), hydraulic subsystems, hot air extraction subsystems, and / or mechanical subsystems (e.g., drive shafts) for operating one or more control surfaces of the aircraft 10, such as slats (not shown).

[0142] However, in an alternative embodiment, one or more further aircraft subsystems 152 may be installed in a recess provided in the second riblet portion 130 defining the second portion of the second cavity 142 during step 205, thereby enabling the installation of one or more further aircraft subsystems 152 in the second riblet portion 130 while the first riblet portion 120 is fixed to the forward spar 21.

[0143] Referring to Figure 5F, when the first riblet portion 120 is attached to the front spar 21, the second riblet portion 130 is brought together with the first riblet portion 120 such that the second rear mounting portions 132 and 134 provided on the second riblet portion 130 are aligned with the front mounting portions 125 and 127 provided on the first riblet portion 120.

[0144] Next, the second rear mounting portions 132 and 134 of the second riblet portion 130 are attached to the front mounting portions 125 and 127 of the first riblet portion 120 by inserting fasteners (e.g., bolts) into the fastener holes provided in the first riblet portion 120 and the second riblet portion 130 during step 206, thereby fixing the second riblet portion 130 to the first riblet portion 120.

[0145] As described above, in some examples, the front mounting portions 125 and 127 provided on the first riblet portion 120, or the second rear mounting portions 132 and 134 provided on the second riblet portion 130, can be pre-attached with restraining nuts (not shown).

[0146] Therefore, during step 206, each fastener (e.g., a bolt) may be inserted through the access hole 106 provided in the D-nose cover 102 into the respective channels defined by the second rear mounting portions 132, 134 and the front mounting portions 125, 127, before being secured via their respective nuts.

[0147] Finally, during step 207, the D-nose cover 102 is attached to the second riblet section 130, thereby completing the assembly of the fixed leading edge assembly 100.

[0148] In the illustrated embodiment, it should be understood that method steps 201 to 207 are performed sequentially.

[0149] However, it should be understood that in other embodiments, step 207 may be performed before step 206 to obtain a fixed leading edge module 300 comprising a D-nose cover 102 and a plurality of second riblet portions 130 to which the D-nose cover 102 is attached.

[0150] The second rear mounting portions 132, 134 of the second riblet portion 130 are then attached to the front mounting portions 125, 127 of one or more first riblet portions 120 during step 206, thereby enabling the fixed leading edge module 300 to be attached to the forward spar 21 of the main wing box assembly 20.

[0151] It should also be understood that in some embodiments in which one or more further aircraft subsystems 152 are installed in recesses provided in the second riblet portion 130, step 205 may be performed before step 204.

[0152] Therefore, in addition to improving accessibility for aircraft assembly personnel, the claimed method according to the present invention enables aircraft assembly personnel to perform work on the second riblet section 130 simultaneously when the first riblet section 120 is joined to the forward spar 21, thereby helping to further reduce airfoil assembly time and thus further improve production throughput.

[0153] Although the present invention has been described above in relation to an aircraft wing 12, it should be understood that aspects of the present invention may also be used for constructing other types of airfoil structures on aircraft, or for use in a wider range of non-aerospace applications.

[0154] Where the term "or" appears, it should be interpreted as meaning "and / or" in such a way that the items mentioned are not necessarily mutually exclusive and can be used in any appropriate combination.

[0155] Although the present invention has been described above with reference to one or more preferred embodiments, it will be understood that various changes or modifications can be made without departing from the scope of the invention as defined in the appended claims.

Claims

1. A riblet for a fixed leading edge (FLE) assembly comprising a first riblet portion and a second riblet portion, The first riblet portion comprises a first rear mounting portion for attaching the first riblet portion to the main wing box assembly, and a front mounting portion opposite to the first rear mounting portion. A riblet, wherein the second riblet portion is provided with a second rear mounting portion for attaching the second riblet portion to the front mounting portion of the first riblet portion.

2. The riblet according to claim 1, wherein the front mounting portion of the first riblet portion and the second rear mounting portion of the second riblet portion each have fastener holes, and the riblet further comprises at least one fastener extending in the chord direction between the fastener holes.

3. The riblet according to claim 2, wherein at least one of the front mounting portion and / or the second rear mounting portion is provided with an eccentric bush for adjusting the position and / or orientation of the fastener hole relative to the second rear mounting portion and / or the front mounting portion.

4. The riblet according to claim 1, wherein the first rear mounting portion of the first riblet portion does not have fastener holes before aligning the first riblet portion with the main wing box assembly.

5. The riblet according to claim 1, wherein the first riblet portion comprises first and second rear projections spaced apart in the thickness direction, and the first riblet portion further comprises a first cavity defined between the first and second rear projections, the first cavity being configured to receive one or more aircraft subsystems.

6. The riblet according to claim 1, wherein the first riblet portion comprises a plurality of first rear mounting portions spaced apart in the thickness direction, and optionally, the plurality of first rear mounting portions are located on the same plane.

7. The riblet according to claim 6, as a result of claim 5, wherein the plurality of first rear mounting portions are located on the first and second rear projections.

8. The riblet according to claim 1, wherein the second riblet portion is substantially D-shaped when viewed from the wingspan direction.

9. The riblet according to claim 1, further comprising a second cavity formed between the first riblet portion and the second riblet portion, wherein the second cavity is configured to receive one or more aircraft subsystems.

10. The riblet according to claim 9, wherein the riblet has a joining line that penetrates the thickness of the riblet between the first riblet portion and the second riblet portion, and the joining line intersects with the second cavity.

11. The riblet according to claim 1, A fixed front edge (FLE) assembly comprising: a D-nose cover defining the aerodynamic surface of the fixed front edge assembly, wherein the D-nose cover is attached to the second riblet portion.

12. The fixed leading edge (FLE) assembly according to claim 11, wherein the fixed leading edge (FLE) assembly comprises a plurality of riblets arranged at equal intervals in the wingspan direction along the fixed leading edge assembly.

13. The fixed leading edge (FLE) assembly according to claim 11, wherein the D-nose cover is not directly joined to the first riblet portion.

14. A fixed leading edge (FLE) module, A D-nose cover defines the aerodynamic surface of the fixed leading edge (FLE) module, A fixed leading edge (FLE) module comprising: a second riblet portion having a second rear mounting portion for attachment to a front mounting portion of a first riblet portion, wherein the D-nose cover is attached to the second riblet portion.

15. A wing-shaped structure, A main wing box assembly having a forward spar and at least one airfoil cover defining the aerodynamic surface of the airfoil structure, A wing structure comprising: a fixed leading edge (FLE) assembly according to claim 11, wherein the fixed leading edge assembly is attached to the forward spar via the first rearward attachment portion of the first riblet portion.

16. The airfoil structure according to claim 15, wherein both the airfoil cover and the D-nose cover form substantially the same aerodynamic surface.

17. The airfoil structure according to claim 15, wherein the airfoil structure is an aircraft wing.

18. An aircraft comprising the wing-shaped structure described in claim 15.

19. A method for assembling the airfoil structure according to claim 15, wherein the method is: a) Aligning the first rear mounting portion of the first riblet portion with the respective mounting fixtures provided on the front spar of the airfoil structure, b) Drilling at least one hole in the airfoil structure to receive each fastener, wherein the hole extends through the fastener and through the first rear mounting portion of the first riblet portion, c) Inserting a fastener into the at least one hole in order to attach the first riblet portion to the mounting fixture provided on the front spar, d) After the first riblet portion is attached to the front spar, the second rear mounting portion of the second riblet portion is attached to the front mounting portion of the first riblet portion, Methods that include...

20. A riblet for an airfoil structure, The leading edge nose section, A tail section configured to facilitate attachment of the leading edge nose section to the leading edge spar of the airfoil structure, A riblet comprising a joining line extending through the thickness of the riblet between the leading edge nose portion and the tail portion.

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