Aircraft assembly including wing tip device

Abstract

The present application relates to an aircraft assembly. The aircraft assembly has a wingtip device connected to the wingtip of a wing by a first connector, a second connector, and a third connector. The wingtip device includes a front device beam and a rear device beam. The first connector is associated with the rear device beam. The second connector is spaced in front of the first connector in a chordwise direction, and the third connector is spaced in the chordwise direction behind the first connector. The third connector includes a plug mounting structure.

Description

Technical Field

[0001] The present invention relates to an aircraft assembly. In particular, the present invention relates to an aircraft assembly comprising a wingtip device connected to the wingtip of a wing. The present invention also relates to a wingtip device, in particular a winglet, and a method of assembling a wingtip device with a wingtip of a wing. Background Art

[0002] It is known that wingtip devices are arranged at the wingtips of aircraft wings. Devices such as winglets, inclined wingtips and wing blades are collectively referred to as aerodynamic wingtip devices. Such devices are used to reduce the effects of lift-induced drag.

[0003] Lift-induced drag is caused by the generation of vortices at the wingtips. This drag is mitigated by an increase in wingspan. An increase in wingspan in the plane of the wing is not always possible due to space requirements at, for example, airports. Therefore, out-of-plane extensions of the wing are often used to increase the effective wingspan without increasing the geometric span of the aircraft. These out-of-plane extensions take the form of aerodynamic wingtip devices.

[0004] The wing tip device is usually attached to the wing tip of the wing by means of a connector connecting the wing spar with the wing tip device spar. A series of splice plates or butt-straps may be used, spanning the upper and lower skins of the wing tip device and the wing at the point where the wing tip device and the wing join.

[0005] The butt-joints transfer the loads through the wing skin, which is primarily designed to absorb bending loads across the span, but is not well suited to absorbing localized, concentrated loads. In addition, many joints are required on the wing skin to spread the applied loads. While this has the desired effect of reducing the load at each joint, this creates an over-static system, making it difficult to predict the load at each point. As a result, each joint is typically over-designed, increasing the weight and cost of the aircraft.

[0006] Another problem is that the interface between the components is very sensitive to geometric differences caused by the tolerance stack-up at the interface. Therefore, any mismatch between the two components needs to be resolved at the time of assembly. This increases the cost of assembly and makes it more difficult to replace the wing tip device in service. Therefore, the ease of replacement of the wing tip device is reduced.

[0007] Furthermore, temperature effects and in-service loading may result in differential expansion or contraction of the wing tip device and the wing tip, which may induce high stresses at the mounting point. Summary of the invention

[0008] According to one aspect of the present invention, a wingtip device is provided, which is connected to the wingtip of a wing by a first connector, a second connector and a third connector, the wingtip device comprising a front device beam and a rear device beam, wherein the first connector is associated with the rear device beam, the second connector is spaced in front of the first connector in a chordwise direction, the third connector is spaced in rear of the first connector in a chordwise direction, and the third connector comprises a plug mounting structure.

[0009] By this arrangement, the movement of the wing tip device behind the rear device beam is constrained, which helps to provide rigidity of the wing tip device near and at the trailing edge.

[0010] Thus, relative bending between the wings towards the trailing edge of the wings is limited by the plug mounting structure, thereby contributing to rigidity in the thickness direction.

[0011] A second connection member may be associated with the front device beam.

[0012] By this arrangement the first and second connectors act via the main load bearing member of the wing tip device.

[0013] The wing tip may include a wing trailing edge, the wing tip device may include a device trailing edge, and the third connector may be configured to connect the device trailing edge to the wing trailing edge.

[0014] This configuration therefore helps to limit movement of the trailing edge of the wing tip device relative to the wing tip.Flutter and relative deflection of the trailing edge of the wing tip device may be limited by the rigid connection provided by the plug mounting structure.

[0015] The wing tip device may include a closing rib located rearwardly of the rear device beam, wherein the plug mounting structure may be associated with the closing rib.

[0016] The plug mounting structure can be located on the closed rib. By this arrangement, the forces acting by means of the upper and lower covering parts of the skin of the wing can be limited.

[0017] The wing tip may comprise a front spar and a rear spar, wherein the first connection may be associated with the rear spar. The second connection may be associated with the front spar. Thus, the first connection and the second connection act by means of a main load-bearing member of the wing tip device.

[0018] The wing tip may include a trailing edge end rib located rearwardly of the rear spar, and the plug mounting structure may be associated with the trailing edge end rib. The plug mounting structure may be located on the trailing edge end rib.

[0019] The plug mounting structure may include a plug associated with the wing tip device or the wing tip, and a plug retainer associated with the other of the wing tip device or the wing tip for receiving the plug in a male / female connection.

[0020] The plug may be located on the wing tip device and the plug holder may be located on the wing tip. This contributes to ease of assembly.

[0021] The plug retainer may include a bushing.

[0022] The bushing may include a wear plate.

[0023] The plug retainer may include an elongated retainer slot extending in the chordwise direction.

[0024] The height of the retainer slot can be configured to be roughly consistent with the diameter of the plug in a direction perpendicular to the chord-wise direction. With this arrangement, movement towards a static load path can be achieved and thermal expansion can be allowed. In some embodiments, some adjacent components of the plug mounting structure can be formed of composite materials and other components can be formed of metallic materials. These materials can have different thermal expansion rates and such differences can be taken into account. In an embodiment, the wingtip device is primarily formed of a composite material and the wingtip is primarily formed of a metallic material.

[0025] The plug may be slidable in the slot between a first state in which the trailing edge of the wingtip device is not aligned with the wingtip trailing edge and a second state in which the trailing edge of the wingtip device moves into alignment with the wingtip trailing edge. The trailing edge of the wingtip device may be movable in response to aerodynamic forces acting on the wingtip device during flight. When the wingtip device is not subjected to aerodynamic forces, the plug may be slidable in the slot to reduce static forces acting on the wingtip device.

[0026] The first connector may include a first plug mounting structure, and the second connector may include a second plug mounting structure, wherein the plug mounting structure as described above may be a third plug mounting structure.

[0027] Therefore, the use of this connector configuration aids assembly and also provides a rigid connection between the wing tip and the wing tip device. In addition, the easy replacement of the wing tip device is enhanced.

[0028] The first plug mounting structure may include a first plug associated with a wingtip device or a wingtip, and a first plug retainer associated with the other of the wingtip device or the wingtip; the second plug mounting structure may include a second plug associated with a wingtip device or a wingtip, and a second plug retainer associated with the other of the wingtip device or the wingtip; and wherein the plug and plug retainer as described above may be a third plug and a third plug retainer.

[0029] Each connector may be configurable between an engaged state, in which the corresponding plug is received by the corresponding plug holder in a male / female connection, and a disengaged state, in which the corresponding plug is removed from the corresponding plug holder.

[0030] When the wing tip device is engaged with the wing tip, the first connection member may be configured to move into the engaged condition of the first connection member before the second connection member moves into the engaged condition of the second connection member.

[0031] When the wing tip device is engaged with the wing tip, the second connection member may be configured to move into the engaged condition of the second connection member before the third connection member moves into the engaged condition of the third connection member.

[0032] This arrangement simplifies the assembly of the wing tip device with the wing tip. Therefore, each connection piece is aligned and engaged individually. In addition, this arrangement ensures that the connection pieces on the main load-bearing member are engaged first.

[0033] The third plug may stand from a plane extending in the chordwise direction, and wherein a length of the third plug from the plane to a free end of the third plug may be shorter than a length of the first plug from the plane to a free end of the first plug.

[0034] A length of the second plug from the plane to a free end of the second plug may be greater than a length of the third plug from the plane to a free end of the third plug.

[0035] The first plug retainer may include a first retainer aperture, and wherein the first retainer aperture may be sized to substantially conform to a diameter of the plug in both a direction parallel to the chord-wise direction and a direction perpendicular to the chord-wise direction.

[0036] By ensuring a close tolerance fit between the first plug holder and the first plug the wing tip device can be accurately positioned and the other plugs can be aligned.

[0037] The second plug retainer may include an elongated second retainer slot extending in the chordwise direction, and wherein a height of the second retainer slot may be configured to coincide with a diameter of the plug in a direction perpendicular to the chordwise direction.

[0038] Thus, thermal expansion can be taken into account and a movement towards a statically determinate load path can be provided at the second connection. Thus, a weight saving can be achieved.

[0039] When assembled, the wingtip and the wingtip device may together define a span-wise axis, wherein the elongated axis of each of the plugs is offset from the span-wise axis at the junction of the wingtip and the wingtip device, and optionally, wherein the offset angle is 2 to 6 degrees, and optionally, wherein the offset angle is 4 degrees.

[0040] The elongated axis of each of the plugs may extend upwardly from the wing tip device.

[0041] Thus, the approach angle during assembly is configured to provide ease of engagement of the components and limit the likelihood of interference.

[0042] The wing tip may include a wing skin, and the wing tip device may include a wing tip device skin, and the aircraft assembly may include a butt strap between the wing skin and the wing tip device skin.

[0043] The wing skin may be a metallic material and the wing tip device skin may be a composite material.

[0044] Before assembling the wing tip and the wing tip assembly, the butt strap may be a first butt strap formed of a metal material on the wing tip assembly skin, and the wing tip assembly may be a second butt strap formed of a composite material on the wing skin. When the wing tip and the wing tip assembly are connected together, this arrangement assists assembly by securing parts of the same material to each other.

[0045] The or each butt strap may be arranged only at or in front of the first connection. Thus, the assembly time of the wing tip device and the wing tip is reduced. The loading is carried out by the plug mounting structure, thereby reducing the loading of the wing skin and the wing tip device skin.

[0046] The wingtip device may be a winglet.

[0047] According to one aspect of the present invention, a wingtip device is provided, which is configured to be connected to the wingtip of an aircraft wing, the wingtip device comprising: a front device beam; a rear device beam; a first load-bearing wingtip connection plug, which is associated with the rear device beam; a second load-bearing wingtip connection plug, which is spaced in front of the first plug in the chordwise direction; and a third wingtip connection plug, which is spaced behind the first plug in the chordwise direction.

[0048] A second plug may be associated with the front device beam.

[0049] The wing tip device may comprise a wing tip device trailing edge, wherein the third plug may be associated with the wing tip device trailing edge.

[0050] According to one aspect of the present invention, a method for assembling a wingtip device with a wingtip of a wing is provided, the method comprising: positioning the wingtip device relative to the wingtip; engaging a first plug with a first plug holder, the first plug being associated with a rear device beam and one of the wingtip device or the wingtip, the first plug holder being associated with the other of the wingtip device or the wingtip; subsequently, engaging a second plug with a second plug holder, the second plug being spaced in front of the first plug in a chordwise direction and being associated with one of the wingtip device or the wingtip, the second plug holder being associated with the other of the wingtip device or the wingtip; and subsequently, engaging a third plug with a third plug holder, the third plug being spaced behind the first plug in a chordwise direction and being associated with one of the wingtip device or the wingtip, the third plug holder being associated with the other of the wingtip device or the wingtip.

[0051] According to one aspect of the present invention, a wingtip device is provided, which is configured to be connected to the wingtip of an aircraft wing, and the wingtip device includes: a first load-bearing wingtip connection plug; a second load-bearing wingtip connection plug, which is spaced in front of the first plug in the chord-wise direction; and a third wingtip connection plug, which is spaced behind the first plug in the chord-wise direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Embodiments of the present invention will now be described with reference to the accompanying drawings, in which:

[0053] Figure 1 It is a three-dimensional image of the aircraft;

[0054] Figure 2 is a schematic diagram of the leading edge of a wingtip having a wingtip device;

[0055] Figure 3 yes Figure 2 A schematic diagram of a wing tip and a wing tip device as shown in , wherein the wing tip device is detached from the wing tip;

[0056] Figure 4 yes Figure 3 A schematic partially cutaway plan view of a wing tip and a portion of a wing tip device shown in FIG.

[0057] Figure 5 yes Figure 3 A schematic plan view of a wing tip and a portion of a wing tip device as shown in FIG.

[0058] Figure 6 yes Figure 2 a perspective view of a portion of the wing tip device shown in , having a plug for mounting with the wing tip shown;

[0059] Figure 7 yes Figure 2 A plan view of the wing tip device shown in;

[0060] Fig. 8A yes Figure 2 a perspective view of the outboard end of the wing tip shown in , showing a plug holder for receiving a plug of the wing tip device shown;

[0061] Figure 8B yes Fig. 8A A schematic diagram of the plug retainer shown in ;

[0062] Fig. 9A yes Figure 3 A schematic plan view of a wing tip and a portion of a wing tip device shown in a first partially assembled state, wherein a first plug is received by a first plug holder;

[0063] Fig. 9B yes Fig. 9A A schematic plan view of a wing tip and a portion of a wing tip device shown in FIG. 1 in a second partially assembled state, wherein the first plug and the second plug are received by the first plug holder and the second plug holder; and

[0064] Fig. 9C yes Fig. 9A A schematic plan view of a wing tip and a portion of a wing tip device shown in FIG. 1 in a third partially assembled state, wherein a first plug, a second plug and a third plug are received by a first plug holder, a second plug holder and a third plug holder. DETAILED DESCRIPTION

[0065] Aircraft 10 Figure 1 . The aircraft 10 includes a fuselage 11. Two wings 12 extend from the fuselage 11. It should be understood that the fuselage 11 and the wings 12 can be formed in a variety of shapes and contours according to the specific application. Each wing 12 has a wing root 13 at the junction with the fuselage 11. The wing 12 has a wing tip 20 at the distal end relative to the wing root 13. The wing 12 has a leading edge 15 and a trailing edge 16. The wing 12 includes a wing box 17. The wing box forms the main body of the wing 12.

[0066] In the following description, the term "front" refers to a component towards the leading edge of the wing, and the term "rear" refers to a component towards the trailing edge of the wing. The terms "front" and "rear" should be interpreted accordingly. The position of a feature may be interpreted relative to other components, for example a front component may be arranged on the front side of another component, but the front component is towards the rear of the wing. The trailing edge relates to the rearmost part behind the rear spar.

[0067] One of the wings 12 will now be described. Figure 2The wing tip 20 is formed by the end of the wing 12. A wing tip device 30 is located at the wing tip 20. In this example, the wing tip device 30 is a winglet. The wing tip 20 terminates at the outboard end 18. The wing tip device 30 extends from the wing tip 20. The wing tip device 30 extends from the outboard end 18.

[0068] The wing 12 has a spanwise axis extending in a direction from the wing root 13 to the wing tip 20. The wing tip device 30 extends in the spanwise direction from the wing tip 20. The wing 12 has a chordwise axis extending in a direction from the leading edge 15 to the trailing edge 16. The wing 12 and the wing tip device 30 each experience aerodynamic lift acting through the center of pressure.

[0069] The wing tip device 30 is attached to the wing tip 20 at the outboard end 18. The wing tip device 30 is Figure 3 and Figure 7 The mounting arrangement 40 (eg Figures 1 to 8B ) to mount the wingtip device 30 to the wingtip 20. Aerodynamic forces act on the wingtip device 30, so the wingtip device 30 is stably attached to the outboard end 18 by the mounting arrangement 40. Torque may act on the wingtip device 30 to force the wingtip device 30 to rotate about an axis extending along the spanwise direction. Torque may act on the wingtip device 30 to force the wingtip device 30 to rotate about an axis extending along the chordwise direction.

[0070] exist Figures 2 to 4 In the drawing, a wing assembly 19 is shown in schematic form, the wing assembly 19 comprising a wing tip 20 and a wing tip device 30 .

[0071] The wing tip 20 includes a front spar 21 and a rear spar 22. Each of the front spar 21 and the rear spar 22 extends in a generally spanwise direction. The front spar 21 and the rear spar 22 converge toward the wing tip 20 along the span of the wing. A series of ribs are positioned along the span and extend in the chordwise direction of the wing. The wing tip 20 is covered by a wing skin 24, which includes an upper wing covering portion 24a and a lower wing covering portion 24b. The spars and ribs are covered by a wing skin that is primarily designed to present an aerodynamic surface to the airflow. The wing tip 20 terminates at the outer end 18.

[0072] The wing tip 20 has an end rib 26. The end rib 26 extends between the front spar 21 and the rear spar 22. The end rib 26 is located at the outboard end 18. When the wing tip device 30 is removed from the wing tip 20, the end rib 26 is exposed.

[0073] The wing tip 20 has a trailing edge end rib 27. The trailing edge end rib 27 is arranged behind the rear spar 22. The trailing edge end rib 27 extends from the rear spar 22. The trailing edge end rib 27 is located at the outboard end 18. When the wing tip device 30 is removed from the wing tip 20, the trailing edge end rib 27 is exposed.

[0074] The wingtip device 30 , which is a winglet in this embodiment, comprises a wingtip device root 31 and a free end 32 which is distal to the wingtip device root 31 and vertically spaced apart from the wingtip device root 31 .

[0075] The wing tip device 30 includes a front device beam 33 and a rear device beam 34. The front device beam 33 extends from a middle position between the free end portion 32 and the device root 31 and extends to the device root 31. The front device beam 33 is arranged toward the device leading edge 35. The rear device beam 34 extends from a middle position along the wing tip device 30 toward the device root 31. The rear device beam 34 deviates from the front device beam 33 as it approaches the device root 31. The rear device beam 34 is arranged at a substantially middle position of the device root 31 along the device root 31 in the chord direction. The rear device beam 34 is arranged behind the front device beam 33 toward the device trailing edge 36.

[0076] The wing tip device skin 39 covers the wing tip device 30 to present an aerodynamic surface to the airflow. The wing tip device skin 39 has an upper device covering portion 39a and a lower device covering portion 39b.

[0077] The wing tip device 30 has a root rib 37. The root rib 37 extends between the front device beam 33 and the rear device beam 34. The root rib 37 is located at the device root 31. When the wing tip device 30 is removed from the wing tip 20, the root rib 37 is exposed.

[0078] The wing tip device 30 has a closed rib 38. The closed rib 38 is arranged behind the rear device beam 34. The closed rib extends from the rear device beam 34. The closed rib 38 is located at the device root 31. When the wing tip device 30 is removed from the wing tip 20, the closed rib 38 is exposed.

[0079] The mounting arrangement 40 includes a first connector 41, a second connector 42, and a third connector 43. The mounting arrangement 40 includes a first upper butt joint strap 44 and a second lower butt joint strap 45. Figure 3 As shown in , the wing tip together with the wing tip arrangement defines a spanwise axis 46 .

[0080] Go to Figure 3 , Figure 4 and Figure 6 It will be apparent that the wingtip device 30 is attached to the wingtip 20 at three main attachment points A, B and C.

[0081] The front device beam 33 is attached to the front spar 21 by a second connection 42 located at an attachment point B. The rear device beam 34 is attached to the rear spar 22 by a first connection 41 located at an attachment point A. The wingtip device trailing edge 36 is attached to the wing trailing edge 16 by a third connection 43 located at an attachment point C. The first connection 41, the second connection 42 and the third connection 43 are located at the device root 31.

[0082] The first connector 41 includes a first plug 50 as a plug mounting structure. The first plug 50 protrudes from the device root 31. The first plug 50 includes an elongated pin 51. The first plug 50 is located on the rear device beam 34. A first plug fitting 52 mounts the first plug 50 to the root end 34a of the rear device beam 34. The first plug fitting 52 is associated with the rear device beam 34. Loading via the rear device beam 34 can be applied through the first plug 50. The first plug 50 extends from the root end 34a in the spanwise direction. The first plug 50 has a first plug free end 53. The first plug free end 53 is located at the distal end of the first plug 50 relative to the first plug fitting 52. The first plug 50 defines a first extension axis from the first plug fitting 52 to the first plug free end 53.

[0083] The first connector 41 includes a first plug holder 54. The first plug holder 54 is configured to receive the first plug 50. The first plug holder 54 is located on the wing tip 20. The first plug holder 54 is located at the outboard end 18. The first plug holder 54 is located on the rear spar 22. The first plug holder 54 is associated with the rear spar 22. Loading via the rear spar 22 can act through the first plug holder 54.

[0084] The first plug retainer 54 includes a bushing 55. The bushing 55 is formed of bronze, but other suitable materials may also be used. Fig. 8A and Figure 8B As shown in , the bushing 55 includes a first retainer hole 56. The bushing 55 defines a loading surface. The first retainer hole 56 has a size configured to substantially coincide with the diameter of the first plug 50 in both a direction parallel to the chord-wise direction and a direction perpendicular to the chord-wise direction. The first retainer hole 56 has a diameter that forms a tight fit with the first plug 50. Therefore, the first connector 41 acts as a locking pin plug in which the first connector 50 is able to react to lateral forces, and thus all degrees of freedom are constrained. In particular, it is not possible to move in the spanwise direction or in the chord-wise direction.

[0085] The second connector 42 includes a second plug 60 as a plug mounting structure. The second plug 60 protrudes from the device root 31. The second plug 60 includes an elongated pin 61. The second plug 60 is located on the front device beam 33. The second plug fitting 62 mounts the second plug 60 to the root end 33a of the front device beam 33. The second plug fitting 62 is associated with the front device beam 33. Loading via the front device beam 33 can be applied through the second plug 60. The second plug 60 extends from the root end 33a in the spanwise direction. The second plug 60 has a second plug free end 63. The second plug free end 63 is located at the distal end of the second plug 60 relative to the second plug fitting 62. The second plug 60 defines a second extension axis from the second plug fitting 62 to the second plug free end 63.

[0086] The second connector 42 includes a second plug holder 64. The second plug holder 64 is configured to receive the second plug 60. The second plug holder 64 is located on the wing tip 20. The second plug holder 64 is located on the outboard end 18. The second plug holder 64 is located on the front spar 21. The second plug holder 64 is associated with the front spar 21. Loading via the front spar 21 can act through the second plug holder 64.

[0087] The second plug retainer 64 includes a bushing 65. The bushing 65 is formed of bronze, but other suitable materials may also be used. Fig. 8A and Figure 8B As shown in , the bushing 65 includes a second retainer groove 66. The bushing 65 defines a loading surface. The second retainer groove 66 is elongated and extends in the chord direction. The height of the second retainer groove 66 is configured to be substantially consistent with the diameter of the second plug 60 in a direction perpendicular to the chord direction. The length of the second retainer groove 66 is greater than the diameter of the second plug 60. Therefore, the second connector cannot resist the lateral force in the chord direction within a certain limit.

[0088] The release of certain degrees of freedom (e.g., the second plug 60 cannot resist lateral forces) allows the system to have some relative motion to avoid thermally induced stresses while making the loads more predictable (moving toward a statically determinate system). For example, since the joint at the second connector 42 does not need to resist lateral forces, the joint can be made smaller (i.e., can be optimized for more predictable load conditions).

[0089] The third connector 43 comprises a third plug 70. The third plug 70 protrudes from the device root 31. The third plug 70 comprises an elongated pin 71. The third plug 70 is located on the closed rib 38. A third plug fitting 72 mounts the third plug 70 to the inner surface 38a of the closed rib 38. The third plug fitting 72 is associated with the closed rib 38. Loading on the device trailing edge 36 can be applied through the third plug 70. Such loading can be generated by aerodynamic forces acting on the wing tip device 30. The third plug 70 extends from the root end 33a in the spanwise direction. The third plug 70 has a third plug free end 73. The third plug free end 73 is located at the distal end of the third plug 70 relative to the third plug fitting 72. The third plug 70 defines a third elongated axis from the third plug fitting 72 to the third plug free end 73.

[0090] The third connector 43 includes a third plug holder 74 as a plug mounting structure. The third plug holder 74 is configured to receive the third plug 70. The third plug holder 74 is located on the wing tip 20. The third plug holder 74 is located at the outer end 18. The third plug holder 74 is located on the trailing edge end rib 27. The third plug holder 74 is associated with the trailing edge end rib 27. Loading via the trailing edge end rib 27 can act through the third plug holder 74.

[0091] The third plug holder 74 is mounted to the outer side surface 27a of the trailing edge end rib 27. Loading to the wing trailing edge 16 can be effected through the third plug holder 74. Such loading can be generated by aerodynamic forces acting on the wing trailing edge 16.

[0092] The third plug retainer 74 includes a bushing 75. The bushing 75 is formed of bronze, but other suitable materials may also be used. Fig. 8A and 8B As shown in , the bushing 75 includes a third retainer slot 76. The bushing 75 is formed by a wear plate 77. An opening is formed through the trailing edge end rib, which is aligned with the mounting portion of the third plug retainer 74 for the third plug 70 to extend through. The bushing 75 defines a loading surface. The third plug retainer slot 76 is elongated and extends in the chord-wise direction. The height of the third plug retainer slot 76 is configured to be substantially consistent with the diameter of the third plug 70 in a direction perpendicular to the chord-wise direction. The length of the third retainer slot 76 is greater than the diameter of the third plug 70. Therefore, within a certain limit, the third connector 43 cannot resist lateral forces in the chord-wise direction.

[0093] The release of certain degrees of freedom (e.g., the third plug 70 cannot resist lateral forces) allows the system to have some relative motion to avoid thermally induced stresses while making the loads more predictable (moving toward a statically determinate system). For example, since the joint at the third connector 43 does not need to resist lateral forces, the joint can be made smaller (i.e., can be optimized for more predictable load conditions).

[0094] The load acting via the third plug 70 is configured to be lower than the load acting via the first plug 50 and the second plug 60. The third connector 43 is configured to resist the load in the wing trailing edge 16 and the device trailing edge 36. Therefore, the third connector 43 resists the force acting on the wing tip 20 and the wing tip device 30 behind the rear spar 22 and the rear device spar 34. The third connector 43 is used to ensure that the wing skin 24 and the wing tip device skin 39 remain aligned. The wing trailing edge 16 and the device trailing edge 36 are not loaded and may generally flutter during flight. The provision of the third connector 43 ensures that the device trailing edge 36 and the wing trailing edge 16 move together, thereby minimizing the generation of a gap between the wing tip device 30 and the surface of the wing tip 20 during flight. Therefore, the aerodynamic efficiency at the intersection of the wing tip 20 and the wing tip device 30 is maximized. The third connector 43 acts via the ribs located at the wing tip and the wing tip device, so the force acting via the skin is minimized.

[0095] When assembled, the upper butt strap 44 and the lower butt strap 45 of the mounting arrangement 40 extend between the wing tip 20 and the wing tip device 30. The upper butt strap 44 extends between the upper covering portion 24a of the wing skin 24 and the upper covering portion 39a of the device skin 39. The upper butt strap 44 is fixedly mounted between the upper covering portion 24a of the wing skin 24 and the upper covering portion 39a of the device skin 39 and serves as a splicing plate. The lower butt strap 45 extends between the lower covering portion 24b of the wing skin 24 and the lower covering portion 39b of the device skin 39. The lower butt strap 45 is fixedly mounted between the lower covering portion 24b of the wing skin 24 and the lower covering portion 39b of the device skin 39 and serves as a splicing plate.

[0096] In the present embodiment, the wing skin 24 is a metal skin and the wingtip device skin 39 is a composite skin. The upper butt strap 44 is a metal butt strap and is mounted to the composite wingtip device skin 39 before assembling the wing tip 20 and the wingtip device 30. The lower butt strap 45 is a composite butt strap and is mounted to the metal wing skin 24 before assembling the wing tip 20 and the wingtip device 30. This arrangement facilitates alignment of the butt straps 44, 45 and assists in fixation when the wing tip 20 and the wingtip device 30 are connected together.

[0097] Each plug 50, 51, 52 is angularly offset relative to the spanwise axis 46 defined by the wingtip 20 and the wingtip device 30. The extended axis of each plug 50, 51, 52 is offset at a certain angle to the spanwise axis at the intersection of the outboard end 18 of the wingtip 20 and the device root 31 of the wingtip device 30. Each plug 50, 51, 52 extends upward from the device root 31. That is, when assembled, each plug is tilted away from the device root 31 toward the plane of the upper cover 24a of the wing 12. The offset angle is in the range of 2 degrees to 6 degrees. In the present embodiment, the offset angle is 4 degrees. This arrangement allows the wingtip device 30 to be provided to the wingtip 20 from below during assembly.

[0098] Each connecting member 41, 42, 43 can be configured between an engaged state when the wing tip 20 and the wing tip device 30 are in an assembled state, and a disengaged state when the wing tip 20 and the wing tip device 30 are in an assembled state. In the engaged state, the corresponding plug is received by the corresponding plug holder in a male / female connection manner, and in the disengaged state, the corresponding plug is taken out from the corresponding plug holder.

[0099] The first plug 50, the second plug 60 and the third plug 70 extend from the wing tip device 30 to different extents. The third plug 70 stands from a plane extending in the chordwise direction of the wing tip device 30. The length of the third plug 70 from the plane to the third plug free end 73 is shorter than the length of the first plug 70 from the plane to the first plug free end 53. The length of the second plug 60 from the plane to the second plug free end 63 is longer than the length of the third plug 70 from the plane to the third plug free end 73. The first plug 50 protrudes further outward than the second plug 60. The second plug 60 protrudes further outward than the third plug 70.

[0100] It will be noted that since the present invention uses only three attachment points, and by arranging the first and third plugs in chord-wise extending plug receiving slots, it is possible to constrain the wing tip device in such a way that the system is statically determinate. Therefore, each attachment point can be designed according to a known load case. This provides an advantage over the prior art, in which a large number of fixings are typically used for load bearing purposes and thus form an over-static system in which the exact load case on each attachment point is unknown. Therefore, each attachment point must be over-designed to cope with the worst possible case.

[0101] Reference 9A to 9C, a method of attaching a wingtip device is shown. The wing assembly 19 is shown to include a wingtip 20 and a wingtip device 30. The wingtip device 30 is attached to the wingtip 20 at attachment points B, A, C along the chordwise direction from the leading edge to the trailing edge. In the wing assembly 19, the attachment points B, A and C align their horizontal chordwise rotation axes (parallel to the axis Y) as described below. The wingtip device 30 is moved close to the wingtip 20 by a trolley jack or the like. The jack is raised to move the wingtip device 30 so that the first plug 50, the second plug 60 and the third plug 70 are aligned with their corresponding receiving points on the wingtip 20. Due to the offset angle arrangement of the plugs 50, 60, 70, the wingtip device 30 can be provided from slightly below the wingtip 20. The joint can then be assembled.

[0102] When the wing tip device 30 is engaged with the wing tip 20, as shown in FIG. Fig. 9A As shown in , the first connector 41 is configured to first move into the engaged state of the first connector 41 before the second connector 42 and the third connector 43 move into their engaged states. Therefore, it is relatively simple to align a single attachment point. When the free end 53 of the first plug 50 is received by the first plug holder 54, lateral movement is restricted due to the tight fit of the two components. Therefore, the wingtip device 20 is easily moved by rotation to align the second plug 60 with the second plug holder 63. The wingtip device is then further moved in the axial direction so that the first plug 50 and the second plug 60 engage with their respective plug holders, as shown in FIG. Fig. 9B Thus, during assembly, the load requirements can be supported by the first connector 41 and the second connector 42, while the third connector 70 does not carry the load. The wingtip device 30 is prevented from rotating about the wingtip 20 by the first connector 41 and the second connector 42. The wingtip device is then further moved in the axial direction so that the third plug 70 engages with its corresponding plug holder 74, as shown in FIG. Fig. 9C As shown in . The wing tip device 30 is then fully assembled with the wing tip 20. The butt straps 44, 45 are fixed between the skins 24, 39. The jacks can then be removed.

[0103] The above arrangement simplifies the assembly of the wing tip device and the wing tip. Therefore, each connecting member is aligned and engaged sequentially.

[0104] When the wingtip device 30 is engaged with the wingtip, the first connection may be configured to move into the engaged condition of the first connection before the second connection moves into the engaged condition of the second connection.

[0105] When the wing tip device is engaged with the wing tip, the second connection member may be configured to move into the engaged condition of the second connection member before the third connection member moves into the engaged condition of the third connection member.

[0106] This arrangement simplifies the assembly of the wing tip device with the wing tip. Therefore, each connection piece is aligned and engaged sequentially. In addition, this arrangement ensures that the connection pieces on the main load-bearing member are engaged first.

[0107] Although in the above-described embodiment, the plug is disposed on the wingtip device and the plug holder is located on the wingtip, it is understood that the arrangement of one or more of the connectors may be reversed. For example, one or more plugs may be located on the wingtip. The advantage of the plug being located on the wingtip is that it enhances the ability of the aircraft to fly without assembling one or more wingtip assemblies on the aircraft. In addition, by positioning the plug on the wingtip device, the ease of aligning the plug with the plug holder may be improved, and thus facilitates a reduction in assembly time.

[0108] When the term "or" appears, this should be interpreted as meaning "and / or" such that the mentioned items are not necessarily mutually exclusive and can be used in any appropriate combination.

[0109] 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: A wingtip device, the wingtip device is connected to the wingtip through a first connection member, a second connection member and a third connection member, the wingtip device comprises a front device beam and a rear device beam, wherein: The first connecting member is associated with the rear device beam, The second connector is spaced in front of the first connector in the chordwise direction, The third connector is spaced behind the first connector in the chordwise direction, and The third connecting member includes a plug mounting structure, wherein the first connection member is configured such that: when the wing tip device is engaged with the wing tip, the first connection member moves into the engaged state before the second connection member moves into the engaged state; and Wherein, the second connector is configured such that when the wing tip device is engaged with the wing tip, the second connector moves into the engaged state before the third connector moves into the engaged state.

2. The aircraft assembly according to claim 1, wherein: The second connecting member is associated with the front device beam.

3. An aircraft assembly according to claim 1 or 2, wherein: The wingtip comprises a wing trailing edge, the wingtip device comprises a device trailing edge, and the third connection member is configured to connect the device trailing edge to the wing trailing edge.

4. An aircraft assembly according to claim 1 or 2, wherein: The wing tip device includes a closed rib located rearwardly of the rear device beam, wherein the plug mounting structure is associated with the closed rib.

5. The aircraft assembly of claim 1, wherein: The wing tip includes a forward spar and a rearward spar, wherein the first connector is associated with the rearward spar.

6. The aircraft assembly according to claim 5, wherein: The wing tip includes a trailing edge end rib located rearwardly of the rear spar, wherein the plug mounting structure is associated with the trailing edge end rib.

7. The aircraft assembly of claim 1, wherein: The plug mounting structure includes a plug associated with one of the wing tip device and the wing tip, and a plug holder associated with the other of the wing tip device and the wing tip for receiving the plug in a male / female connection.

8. The aircraft assembly according to claim 7, wherein: The plug retainer includes an elongated retainer slot extending in the chordwise direction.

9. An aircraft assembly according to claim 8, wherein: The height of the retainer slot is configured to coincide with a diameter of the plug in a direction perpendicular to the chordwise direction.

10. The aircraft assembly of claim 1, wherein: The first connector includes a first plug mounting structure, and the second connector includes a second plug mounting structure, wherein the plug mounting structure of the third connector is a third plug mounting structure.

11. The aircraft assembly of claim 10, wherein: The first plug mounting structure includes: a first plug associated with one of the wing tip device and the wing tip; and a first plug retainer associated with the other of the wing tip device and the wing tip; The second plug mounting structure includes: a second plug associated with one of the wing tip device and the wing tip; and a second plug holder associated with the other of the wing tip device and the wing tip; and Wherein, the third plug installation structure includes a third plug and a third plug retainer.

12. The aircraft assembly of claim 11, wherein: The first plug retainer includes a first retainer aperture, and wherein the first retainer aperture is sized to conform to a diameter of the first plug in both a direction parallel to the chord-wise direction and a direction perpendicular to the chord-wise direction.

13. The aircraft assembly of claim 11, wherein: When assembled, the wing tip and the wing tip device together define a span-wise axis, wherein the elongated axis of each plug is at an offset angle to the span-wise axis at the intersection of the wing tip and the wing tip device.

14. The aircraft assembly of claim 1, wherein: The wingtip comprises a wing skin, the wingtip device comprises a wingtip device skin, and the aircraft assembly comprises a butt joint between the wing skin and the wingtip device skin.

15. An aircraft assembly according to claim 14, wherein: The butt strap is only arranged at the first connecting member or only arranged in front of the first connecting member.

16. A wingtip device, the wingtip device being configured to be connected to the wingtip of an aircraft wing, the wingtip device comprising: Front device beam; rear device beam; a first load bearing wing tip connection plug associated with the rear device beam; a second load-bearing wing tip connection plug, the second load-bearing wing tip connection plug being spaced forward of the first load-bearing wing tip connection plug in a chordwise direction; as well as a third wing tip connection plug, the third wing tip connection plug being spaced behind the first load-bearing wing tip connection plug in the chordwise direction, Wherein, the third wingtip connection plug is erected from a plane extending along the chord-wise direction, and wherein the length of the second load-bearing wingtip connection plug from the plane to the free end of the second load-bearing wingtip connection plug is greater than the length of the third wingtip connection plug from the plane to the free end of the third wingtip connection plug, and is less than the length of the first load-bearing wingtip connection plug from the plane to the free end of the first load-bearing wingtip connection plug.

17. A wingtip device according to claim 16, comprising a wingtip device trailing edge, wherein: The third wing tip connection plug is associated with the wing tip device trailing edge.

18. A method of assembling a wingtip device with a wingtip of an aircraft, the method comprising: positioning the wingtip device relative to the wingtip; engaging a first plug associated with an aft device beam and with one of the wing tip device and the wing tip with a first plug holder associated with the other of the wing tip device and the wing tip; subsequently engaging a second plug spaced forward of the first plug in a chordwise direction and associated with one of the wingtip device and the wingtip with a second plug holder associated with the other of the wingtip device and the wingtip; and subsequently engaging a third plug spaced behind the first plug in the chordwise direction and associated with one of the wingtip device and the wingtip with a third plug holder associated with the other of the wingtip device and the wingtip, Wherein, the third plug stands upright from a plane extending along the chord direction, and the length of the second plug from the plane to the free end of the second plug is greater than the length of the third plug from the plane to the free end of the third plug, and is less than the length of the first plug from the plane to the free end of the first plug.

Images