GB2584409A

GB2584409A - A moveable panel arrangement for a folding wing tip

Info

Publication number: GB2584409A
Application number: GB1906901.2A
Authority: GB
Inventors: Horwood Jack; Morrell Paul; Harding Matt
Original assignee: Airbus Operations Ltd
Current assignee: Airbus Operations Ltd
Priority date: 2019-05-16
Filing date: 2019-05-16
Publication date: 2020-12-09
Also published as: GB201906901D0

Abstract

An aircraft wing (10, fig 1a) comprising a fixed wing 14and a wing tip device 12 rotatable about a hinge 16 at the tip of the fixed wing. The wing further comprises a moveable panel 34 at the boundary between the wing tip device and the fixed wing. In the flight configuration the panel is closed such that the panel is substantially flush with the upper surfaces 30,26 of the wing and wing tip respectively. The panel may be located in the path of a moveable element (for example part of an actuation mechanism, such as a curved rack). During movement to the ground configuration the panel is initially moved up and away from the upper surface of the wing (for example by a linkage assembly).

Description

A MOVEABLE PANEL ARRANGEMENT FOR A FOLDING WING TIP

BACKGROUND OF THE INVENTION

[0001] There is a trend towards increasingly large passenger aircraft, for which it is desirable to have correspondingly large wing spans. However, the maximum aircraft span is effectively limited by airport operating rules which govern various clearances required when manoeuvring around the airport (such as the span and/or ground clearance required for gate entry and safe taxiway usage).

[0002] Therefore, folding wing tip devices have been introduced into passenger aircraft, where a wing tip device is movable between a flight configuration for use during flight, and a ground configuration for use during ground-based operations. In the ground configuration, the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced, thereby allowing use of existing gates and safe taxiway usage.

[0003] When the wing tip device is moved relative to the fixed wing, to reach the ground configuration, it is necessary to avoid clashing between these two structures. In some known arrangements, the interface and/or nature of the rotation of the wing tip device is designed in a manner to avoid clashes. An example of such an arrangement is disclosed in WO 2015/150835. In other arrangements, the wing tip device is rotated about a hinge. Examples of such an arrangement are disclosed in US2017/137110, US2013 /292508 and US 2014/061371. W02019/034432 also discloses an aircraft with a hinged wing tip, together with an actuation unit for actuating the foldable wing tip portion.

[0004] With hinged wing tip devices, it can be challenging providing a geometry that avoids clashing of the structures, yet also fulfils other important design criteria. Examples of such other design criteria that may need fulfilling are: providing a suitable wing geometry in the flight configuration (e.g. having an aerodynamically efficient profile); having effective sealing between wing tip device and fixed wing; accommodating actuation mechanisms within the wing; and/or accommodating the physical structure of the hinge. -2 -

[0005] The present invention seeks to mitigate the above-mentioned problems. Alternatively or additionally the present invention seeks to provide an improved wing tip device arrangement.

SUMMARY OF THE INVENTION

[0006] According to a first aspect of the invention, there is provided an aircraft wing, the aircraft wing comprising a fixed wing and a wing tip device rotatable about a hinge at the tip of the fixed wing. The wing tip device comprises a moveable element that moves along a path, relative to stationary structure at the tip of the fixed wing, when the wing tip device is rotated about a hinge axis of the hinge, between: (i) a flight configuration for use during flight and (ii) a ground configuration for use during ground-based operations, in which ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced. The wing further comprises a panel at the boundary between the wing tip device and the fixed wing, and the wing is arranged such that: in the flight configuration the panel is in a closed position such that the panel is substantially flush with the upper surface of the wing, and the panel is located in the path of the moveable element; during initial movement from the flight configuration to the ground configuration the panel is lifted away from the upper surface of the wing, preferably separating the panel from the upper surface of the wing and; in the ground configuration, the panel is in a position outside the path of the moveable element such that clashing of the moveable element with the stationary structure at the tip of the fixed wing is avoided.

[0007] An arrangement in which, during the initial movement the panel, the panel is lifted away from the upper surface of the wing to separate the panel from the upper surface of the wing, has been found especially useful. This is because it tends to enable effective sealing around the panel, and in some embodiments the full perimeter of the panel. There may also be minimal sliding/rotation at the seal interface. Furthermore, it tends to enable a relatively large panel to be used, thereby allowing the panel to cover other parts of the wing and potentially seal those parts too.

[0008] The panel may be lifted away under a translational movement. The translational movement may have a component, and preferably a major component of movement, in a direction generally perpendicular to the upper surface of the wing. The whole panel may undergo a translational movement. The panel may undergo a rotational movement in combination with a translational movement The panel preferably does not undergo a pure rotational movement.

100091 The panel may have a perimeter. In the flight configuration, the perimeter of the panel may adjoin the surrounding structure of the wing, for example it may adjoin edges of the upper covers of the fixed wing and wing tip device. During the initial movement, the panel is preferably separated from the upper surface of the wing along the perimeter. [0010] The wing may comprise a sealing arrangement. The sealing arrangement may be for creating a seal between the panel and the surrounding structure (for example the surrounding structure of the fixed wing and the wing tip device when the wing tip is in the flight configuration). The seal may be created along substantially the whole perimeter of the panel. The seal is preferably arranged to seal the interior of the wing from airflow over the wing. The seal is preferably a compression seal. The seal may comprise a P-seal. The seal may be supported on a seal support structure.

[0011] Providing such a sealing arrangement is enabled by the nature of the movement of the panel, and such a sealing arrangement may be relatively simple (thereby providing benefits in terms of component count and/or seal maintenance).

[0012] The wing comprises a hinge. The hinge may comprises a hinge structure. The hinge may comprise a plurality of lugs of the wing tip device. The hinge may comprise a plurality of lugs on the fixed wing. The plurality of lugs on the wing tip device may interleave the plurality of lugs on the fixed wing. The plurality of lugs on the wing tip device may be rotatable about the hinge axis relative to the plurality of lugs on the fixed wing. The panel may be arranged (for example sized and shaped) such that in the flight configuration the panel covers the hinge, and more preferably covers the interleaving lugs. Such an arrangement is especially beneficial as it may avoid the need for a sealing arrangement between the lugs (which tends to otherwise need to be relatively complex). Having a relatively large, moveable panel that covers the hinge structure may also -4 -provide benefits for maintenance because it may enable the hinge to be accessed via removal of only the single panel.

[0013] The panel may be coupled to the fixed wing via a linkage assembly. The linkage assembly may comprise a fixed-wing link. The fixed-wing link may be pivotably mounted (for example at one end), about a first pivot on the fixed wing. The fixed-wing link may be pivotably mounted (for example at the other end) about a second pivot on the panel. Such an arrangement may enable the initial lifting movement of the panel to be effected when the panel is moved about the link.

[0014] In some embodiments, the linkage assembly may further comprise a driver arm link. The driver arm link may be pivotably mounted to the wing tip device (for example at one end). Having a driver arm link mounted on the wing tip device has been found to be especially beneficial because it may enable the movement of the panel to be effected by movement of the wing tip device. In other words, it may remove the need to separately actuate the panel. This may be advantageous in providing a simple and reliable way of moving the panel.

[0015] The driver arm link may be pivotably mounted to the fixed-wing link (for example at the other end). The driver arm link may be pivotably mounted to the fixed-wing link to one side of the first pivot such that the driver arm link urges rotation of the fixed-wing link. The driver arm link may be pivotably mounted to the fixed-wing link to the side of the first pivot that is opposite the side of the second pivot.

[0016] The linkage assembly may further comprise a secondary link. The secondary link may be pivotably mounted at one end to the driver arm link. The secondary link may be pivotably mounted at the other end to the panel. The secondary link may be pivotably mounted to the driver arm link at a location between the pivot of the driver arm on the wing tip device and the pivot of the driver arm on the fixed-wing link. The secondary link may be pivotably mounted to the panel at a location outboard of the pivot of the fixed-wing link on the panel. Providing a secondary link may be beneficial in supporting an appropriate orientation of the panel as it is moved during rotation of the wing tip device.

[0017] It may be beneficial to provide a plurality of the above-mentioned linkages (for example corresponding linkages on either side of the panel). It will be appreciated that -5 -referenced herein to features of one of the linkages may equally apply to a plurality of said linkages.

[0018] The linkage assembly may be configured such that when the wing tip device is in the ground configuration, the panel is positioned to shield the hinge. The panel may be positioned such that it extends (for example at an incline) between a location on the fixed wing upper cover inboard of the hinge axis, to a location on the wing tip device outboard on the hinge axis. The panel may be arranged to shield the hinge from above (for example from environmental elements).

[0019] The wing may be arranged such that the panel is moveable in a two-stage movement. The two-stage movement may comprise a first stage comprising the initial movement from the flight configuration to the ground configuration in which the panel is lifted away from the upper surface of the wing, thereby separating the panel from the upper surface of the wing. The first stage may be considered a transition stage as the wing tip device moves towards the ground configuration. The first stage may move the panel from the path of the moveable structure. The first stage may comprise breaking a seal around the panel.

[0020] The two stage movement may comprise a second stage in which the panel is positioned to shield the hinge. Panel may already be moved away from the path of the moveable structure before the second stage of movement.

[0021] In some embodiments of the invention, the panel may comprise a follower. The follower may be constrained to move along a track. The track may be arranged (for example it may be shaped) such that during initial movement from the flight configuration to the ground configuration the panel is lifted away from the upper surface of the wing, thereby separating the panel from the upper surface of the wing and in the ground configuration. The track may be arranged such that panel is in a position outside the path of the moveable element such that clashing of the moveable element with the stationary structure at the tip of the fixed wing is avoided.

[0022] Providing a follower and track arrangement to define the locus of movement may be beneficial in that it may avoid the need for a potentially complex linkage assembly.

[0023] In principle the wing may comprise an actuator for moving the panel. More preferably however, the movement of the panel is effected by movement of the wing tip -6 -device. This may be considered 'passive' actuation of the panel. For example, in some embodiments, the panel may be linked to the wing tip device such that the movement of the panel is effected by the movement of the wing tip device. In some embodiments, the wing tip device may comprise a cam element such that movement of the wing tip device from the flight configuration to the ground configuration results in the cam element exerting an motive force against the panel. The motive force may be arranged to effect the movement of the panel. In some embodiments, a part of the wing tip device (for example an edge of the upper cover) may be linked to the panel to exert the motive force on the panel.

100241 Having passive' actuation of this form has been found to be especially beneficial because it tends to remove the need to separately actuate the panel. This may be advantageous in providing a simple and reliable way of moving the panel.

[0025] In the ground configuration, the panel is in a position outside the path of the moveable element such that clashing of the moveable element with the stationary structure at the tip of the fixed wing is avoided. It will be appreciated that the panel is located outside the path of the moveable element as and when it is located in a position that need not be occupied by the moveable element. For example, the panel may be located beyond the end of the path of the moveable element. In other embodiments, the panel may be located to the side, or otherwise away from, the path of the moveable element.

[0026] The wing may comprise an actuation mechanism for moving the wing tip device from the flight configuration to the ground configuration. The actuation mechanism may comprise the moveable element. Providing a panel for accommodating a moveable element that is part of an actuation mechanism for the folding wing tip, has been found especially beneficial because it enables potentially-advantageous actuation mechanisms to be used, whilst avoiding clashing during movement to the ground configuration.

[0027] The actuation mechanism may comprise a rotary drive. The rotary drive may be arranged to drive the moveable element in a curved path to move the wing tip device between the flight configuration and the ground configuration. The rotary drive may be arranged with an axis of rotation that is parallel to the hinge axis. The rotary drive mechanism may be arranged with an axis of rotation that is parallel to and coincident with the hinge axis. The rotary drive may comprise a geared rotary actuator (GRA). The rotary drive may comprise a pinion. The moveable element may comprise a rack for being driven by the pinion. The rack may be a curved rack for moving along a curved path. The curved path may be curved around the hinge axis. An actuation unit having some of the above-mentioned features of the actuation mechanism, is disclosed in W02019/034432.

100281 The wing tip device may comprise an upper cover. The upper cover may comprise the wing skin of the wing tip device. The upper cover may define part of the upper surface of the wing tip device.

100291 In the flight configuration the upper cover of the wing tip device may adjoin the panel along an interface. The interface is preferably offset from the hinge axis of the wing tip device. The interface is preferably offset outboard from the hinge axis of the wing tip device. In other words, a distal edge of the panel preferably extends outboard of the hinge axis. A proximal edge of the panel preferably extends inboard of the hinge axis.

[0030] The hinge axis may extend through the depth of the wing (for example it may pass through the wing box). Such an arrangement tends to be desirable so that at least some of the structure of the hinge is accommodated within the depth of the wing and does not unduly impact on the aerodynamics of the wing. The interface may be vertically offset from the hinge axis.

[0031] The interface may be arranged such that an edge of the upper cover (of the wing tip device) overlaps the adjoining edge of the panel along an overlap region. The interface may be outboard of the hinge axis of the wing tip device, such that as the wing tip device rotates from the flight configuration to the ground configuration, the upper cover is lifted away from the panel along the overlap region. Such an arrangement may therefore enable the upper cover and the panel to separate.

[0032] The above-mentioned arrangement may also be beneficial during return movement of the wing tip device from the ground configuration to the flight configuration. The wing may be configured such that during return movement from the ground configuration to the flight configuration, the upper cover and the panel contact -8 -each other along the overlap region. The contact may be such that the upper cover draws the panel back down into the closed position.

[0033] The above-mentioned arrangement may be beneficial in that it enables the edge of the upper cover to clamp the panel in place once the wing tip device is in the flight configuration. This may reduce the likelihood of deflections of the panel during flight (for example due to relatively low pressure air across the upper cover).

100341 The tip of the fixed wing may comprise a wing box. The wing box may have a pair of ribs. The wing box may have a pair of spars. The wing box may have an upper and lower cover.

100351 The wing tip device, and preferably the root of the wing tip device, may comprise wing tip box. The wing tip box may comprise a pair of wing tip spars. The wing tip box may comprise a pair of wing tip ribs. The wing tip box may comprise a wing tip upper cover and a wing tip lower cover. When the wing tip is in the flight configuration, the upper and lower covers of the wing tip box may be continuations of the upper and lower covers of the wing box. The panel may be on the upper cover of the wing box such that the panel is flush with the adjoining upper covers.

[0036] Embodiments of the invention may be beneficial where the moveable element, or part of the moveable element is housed in the wing box. The actuation mechanism may be at least partially housed in the wing box of the fixed wing. A rotary drive may be housed in the wing box of the fixed wing. The moveable element, for example a curved rack, may extend out of the wing box of the fixed wing.

[0037] According to another aspect of the invention, there is provided an aircraft incorporating the aircraft wing of the first aspect.

100381 According to another aspect of the invention, there is provided a method of moving a wing tip device from a flight configuration for use during flight, to a ground configuration for use during ground-based operations, in which ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced. The method comprises the steps of having a panel in a closed position in which the panel is located in the path of a moveable element of the wing tip device, and is substantially flush with the upper surface of the wing, lifting the panel away from the upper surface of the wing, thereby separating the panel from the upper -9 -surface of the wing and; continuing to move the panel such that in the ground configuration, the panel is in a position outside the path of the moveable element such that clashing of the moveable element with the stationary structure at the tip of the fixed wing is avoided. In the closed position the perimeter of the panel may surround a hinge structure thereby covering the hinge structure. The step of separating the panel from the upper surface of the wing may expose the hinge structure. The method may comprise the step of actuating the wing tip device from the flight configuration by effecting movement of the moveable element.

[0039] According to yet another aspect of the invention, there is provided a folding wing tip arrangement for an aircraft wing, the arrangement comprising a fixed wing and a hinged wing tip device at the tip thereof, the wing tip device being configurable by a wing tip actuator between: (i) a flight configuration for use during flight and (ii) a ground configuration for use during ground-based operations, in which ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced. The arrangement comprises a moveable panel covering the hinge structure of the wing tip device, and wherein the panel is mounted on a linkage assembly, the linkage assembly spanning the fixed wing and the wing tip device such that movement of the wing tip device effects movement of the linkage assembly, and wherein the linkage assembly is arranged such that during movement of the wing tip device from the flight to the ground configuration, the panel is initially lifted up and away from the upper surface of the wing, to expose the hinge and to allow movement of the wing tip device to the ground configuration without clashing.

[0040] In the flight configuration the panel may be closed and may occupy a space that would be occupied by the actuator when the wing tip device is in the ground configuration. In the ground configuration the moveable panel may be open to allow the actuator to occupy that space. The wing tip device may be hinged for movement between the flight and ground configurations. The linkage assembly may be further arranged such that in the ground configuration, the panel is in a shielding position between the fixed wing and folded wing tip, thereby shielding the hinge structure from above.

[0041] In embodiments of the present invention, the wing tip device is configurable between: (a) a flight configuration for use during flight and (b) a ground configuration for -10 -use during ground-based operations, in which ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced. hi the flight configuration, the span may exceed an airport compatibility limit. In the ground configuration the span may be reduced such that the span (with the wing tip device in the ground configuration) is less than, or substantially equal to, the airport compatibility limit. The airport compatibility limit is a span limit (for example relating to clearance restrictions for buildings, signs, other aircraft). The compatibility limit is preferably a gate limit.

[0042] The wing tip device may be a wing tip extension; for example the wing tip device may be a planar tip extension. In other embodiments, the wing tip device may comprise, or consist of a non-planar device, such as a winglet.

[0043] In the flight configuration the trailing edge of the wing tip device is preferably a continuation of the trailing edge of the fixed wing. The leading edge of the wing tip device is preferably a continuation of the leading edge of the fixed wing. There is preferably a smooth transition from the fixed wing to the wing tip device. It will be appreciated that there may be a smooth transition, even where there are changes in sweep or twist at the junction between the fixed wing and wing tip device. However, there are preferably no discontinuities at the junction between the fixed wing and wing tip device. The upper and the lower surfaces of the wing tip device may be continuations of the upper and lower surfaces of the fixed wing. The span ratio of the fixed wing relative to the wing tip device may be such that the fixed wing comprises at least 70%, 80%, 90%, or more, of the overall span of the aircraft wing.

[0044] When the wing tip device is in the ground configuration, the aircraft incorporating the wing, may be unsuitable for flight. For example, the wing tip device may be aerodynamically and/or structurally unsuitable for flight in the ground configuration. The aircraft is preferably configured such that, during flight, the wing tip device is not movable to the ground configuration. The aircraft may comprise a sensor for sensing when the aircraft is in flight. When the sensor senses that the aircraft is in flight, a control system is preferably arranged to disable the possibility of moving the wing tip device to the ground configuration.

[00451 In the ground configuration the wing tip device may be held in place. For example the wing tip device may be latched or locked in place to prevent movement back towards the flight configuration.

100461 The aircraft is preferably a passenger aircraft. The passenger aircraft preferably comprises a passenger cabin comprising a plurality of rows and columns of seat units for accommodating a multiplicity of passengers. The aircraft may have a capacity of at least 20, more preferably at least 50 passengers, and more preferably more than 50 passengers. The aircraft is preferably a powered aircraft. The aircraft preferably comprises an engine for propelling the aircraft. The aircraft may comprise wing-mounted, and preferably underwing, engines.

100471 It will of course be appreciated that features described in relation to one aspect of the present invention may be incorporated into other aspects of the present invention. For example, the method of the invention may incorporate any of the features described with reference to the apparatus of the invention and vice versa.

100481 Some features herein may have be described with reference to a direction of movement from one configuration (for example the flight configuration) to another configuration (for example the ground configuration). It will be appreciated that the features may also have been equally described, in the reverse motion, with reference to the movement in the opposition direction, and such features will be understood to be disclosed herein. For example, embodiments of the invention may provide a wing arranged such that: in the ground configuration the panel is in an open position outside the path of a moveable element; during final movement from the ground configuration to the flight configuration the panel may be lowered towards the upper surface of the wing, thereby adjoining the panel into the upper surface of the wing and; in the flight configuration the panel is in a closed position such that the panel is substantially flush with the upper surface of the wing.

DESCRIPTION OF THE DRAWINGS

-12 - [0049] Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings of which: [0050] Figure la shows a schematic view of an aircraft wing according to a first embodiment of the invention; [0051] Figure lb shows a schematic view of an aircraft incorporating wings according to Figure 1 a; 100521 Figure lc shows a close up view of the hinge structure linking the wing tip device to the fixed wing; [0053] Figures 2a to 2e show a close-up view of the hinge, both in schematic side view (see left-hand side) and perspective view (see right-hand side) in 10 degree increments as the wing tip device moves from the flight configuration to the ground configuration; [0054] Figure 3a shows a close-up view of the hinge and the surrounding parts of the wing tip device and fixed wing of a wing in a second embodiment of the invention, with some of the other surrounding structure removed for the sake of clarity. The lower image in Figure 3a is a section view through A-A in the upper Figure; [0055] Figure 3b shows the corresponding features of the wing in Figures 3a but with the wing tip device part-way to the ground configuration; [0056] Figure 3c shows the corresponding features of the wing in Figures 3a but with the wing tip device in the ground configuration; [0057] Figure 4a shows a close-up view of the hinge and the surrounding parts of the wing tip device and fixed wing of a wing in a third embodiment of the invention, with some of the other surrounding structure removed for the sake of clarity. The lower image in Figure 4a is a section view through A-A in the upper Figure; 100581 Figure 4b show the corresponding features of the wing in Figures 4a but with the wing tip device part-way to the ground configuration; and [0059] Figure 4c show the corresponding features of the wing in Figures 4a but with the wing tip device in the ground configuration.

DETAILED DESCRIPTION

-13 - [0060] Figure la shows a wing 10 comprising a wing tip device 12 and a fixed wing 14. The wing tip device 12 is configurable between: (i) a flight configuration for use during flight, as shown in figure 1 b and (ii) a ground configuration for use during ground-based operations, as shown in figure la, in which ground configuration the wing tip device 12 is moved away from the flight configuration such that the span of the aircraft wing 10 is reduced.

100611 The wing 10 comprises the wing tip device 12 and the fixed wing 14. Figure lc shows a close-up view of the hinge structure linking the wing tip device to the fixed wing. The wing tip device 12 is hinged to the fixed wing about the hinge 16 having a hinge axis 18. The hinge 16 comprises a series of interleaving lugs 20 on the root of the wing tip device 12 and the tip of the fixed wing. The lugs 20 have apertures 22 through which a hinge pin (not shown) extends (the hinge pin being coaxial with the hinge axis 18). The interleaving lugs 20 are provided in pairs, with a space between for accommodating an actuator mechanism (described in more detail below).

[0062] The interleaving lugs 20 also comprise a series of lower apertures 24 for receiving locking pins (not shown) to hold the wing tip in the flight configuration. The exact nature of the locking arrangement for holding the wing tip device in the flight configuration is not relevant to the present invention and is not described in detail herein.

[0063] The wing tip device 12 comprises an upper cover 26 connected to a wing tip root rib 28. The upper cover 26 forms the outer skin on the upper surface of the wing tip device 12.

[0064] The fixed wing 14 comprises an upper cover 30 connected to a tip rib 32. The upper cover 30 forms the outer skin on the upper surface of the fixed wing 14.

100651 The upper covers 26, 30 of the wing tip device 12 and the fixed wing 14 are not shown in Figure I c in order to better illustrate the structure of the hinge.

[0066] Figures 2a to 2e show part of the wing 10 in the first embodiment of the invention, and reference will now be made to these Figures.

[0067] Figures 2a to 2e shows a close-up view of the hinge, both in schematic side view (see left-hand side) and perspective view (see right-hand side) as the wing tip device moves from the flight configuration to the ground configuration. The images show the wing tip device moving sequentially through increments of 10 degrees rotation of the -14 -wing tip device from the flight configuration (0 degrees) to the ground configuration (86 degrees). The upper cover 30 of the fixed wing is not shown in the right-hand images, but it is confirmed that the cover 30 is flush with the panel 34 when the wing tip is in the flight configuration (see left-hand image). Figures 2a-2e may give the impression to some readers that the panel 34 is inclined downwardly, but it is confirmed this is only an optical illusion resulting from the hinge axis 18 being parallel to the line of flight, but the wing 10 is swept.

[0068] In the embodiment of Figures 2a and 2b, the wing 10 comprises an actuation mechanism 11 comprising a geared rotary actuator GRA (not fully visible in the Figures) and a curved rack. The GRA has an output shaft onto which a pinion gear is mounted. The pinion gear is coupled, via a secondary gear, to the curved rack. The curved rack includes a support structure which is fixedly attached to a root of the wing tip device via a pair of lugs. The GRA is arranged to drive the rack in a curved path to move the wing tip device between the flight configuration and the ground configuration. The GRA rotates the pinion such that the rack is rotated outboard, thereby moving the wing tip device such that it rotates about the hinge axis. The second embodiment of the invention comprises a the same type of actuation mechanism (illustrated in Figures 3a-3c) and features of the actuation mechanism shown in the second embodiment are equally applicable to the first embodiment.

[0069] In the first embodiment of the invention, shown in Figures 2a-2e, the wing comprises a moveable panel 34, to which reference will now be made: [0070] In the flight configuration, the panel 34 is closed and the panel 34 is substantially flush with the surrounding upper surfaces of the covers 26, 30. The panel 34 is relatively large and extends over the hinge structure 16, including over the interleaving lugs 20 (see Figure I c). A seal arrangement 17 comprising a support frame and P-seal, extends around the perimeter of the panel 34 to create a seal between the panel 34 and the surrounding covers 26, 30. This inhibits leakage flow at the interface between the panel 34 and the surrounding structure and ensures a relatively aerodynamically efficient arrangement during flight.

-15 - [0071] Having a relatively large panel, especially a panel that extends over the hinge structure 16, 20, has been found to be especially beneficial because it avoids the need for complex sealing arrangements (for example inter-lug seals) within the hinge itself [0072] Figures 2a-2e shows the movement of the panel 34 as the wing tip device 12 undergoes initial movement from its closed position in the flight configuration (top image of Figure 2a, 0 degrees rotation) towards the ground configuration (final image in Figure 2e, 86 degrees rotation). As illustrated in the first few images of Figures 2a and 2b, the panel 34 is initially lifted away from the upper surface of the wing, thereby separating the panel 34 from the upper surface of the wing along the whole perimeter of the panel 34. Such an arrangement is beneficial as it enables effective breaking of the seal along the seal arrangement 17.

[0073] This initial movement is created by the 3-bar linkage assembly 50. The linkage assembly 50 comprises a fixed-wing link 52, a driver link 58, and secondary link 60. [0074] The fixed-wing link 52 is pivotably mounted on the fixed wing 14 about a first pivot 54. The fixed-wing link 52 is pivotably mounted at a second pivot 56, at its distal end, to the panel 34.

[0075] The driver link 58 is pivotably mounted, at a pivot 62, to the wing tip device 12 at one end. At its other end, the driver link 58 is pivotably mounted, at another pivot 64, to the fixed-wing link 52. The driver link 58 thus spans the fixed wing 14 and the wing tip device 12.

[0076] The secondary link 60 is pivotably mounted at one end 68, part way along the driver arm link 58. The secondary link 60 is pivotably mounted at the other end to the underside of the panel 34 at a panel pivot 72. The panel pivot 72 is outboard of the second pivot 56 (at which the fixed-wing link is pivotably connected to the panel).

[0077] This configuration of linkage assembly 50 has a number of advantages. Firstly, providing a driver link 58 that is connected to the wing tip device 12 enables the movement of the panel 34 to be effected by rotation of the wing tip device 12 and negates the need for a separate panel actuator. This may ensure simple and reliable movement of the panel 34. Secondly, connecting the driver link 58 to the fixed-wing link 52 and to the secondary link 60 enables the movement of the driver link 58 to effect an initial lifting movement of the panel 34.

-16 - [0078] Reference is now made to Figures 2d and 2e showing the latter stages of movement of the panel 34 and the resulting position when the wing tip device 12 is in the ground configuration. In the ground configuration, the panel 34 is in a position outside the path of the hinge structure 16, 20 such that clashing of the hinge structure 16, 20 at the tip of the fixed wing is avoided. In the ground configuration, the rack of the actuator assembly has also been moved sufficiently far that it protrudes above the envelope of the wing, and more specifically it occupies the space that part of the panel 34 occupied when the wing tip device 12 was in the flight configuration. To accommodate the movement of the rack, the panel 34 has been moved so that is no longer in the path of the rack. Such an arrangement enables the GRA/rack actuation mechanism 11 to be used on a hinged wing tip device because it prevents the rack clashing with the covers 30 of the fixed wing. [0079] In the first embodiment of the invention, the linkage assembly 50 is also configured such that when the wing tip device 12 is in the ground configuration, the panel 34 is inclined between the upper covers 26, 30 of the fixed wing and the (rotated) wing tip device. This position is arranged to shield the hinge 16 both aesthetically and from environmental factors. The panel 34 is drawn into this position by virtue of the linkage assembly 50 and the relative locations of the links/pivots as the wing tip device 12 rotates. As illustrated in Figures 2d-2e, once the pivot 64 of the driver link 60 moves below the pivot 54 of the fixed-wing link 52, and below the pivot 62 at which the driver link 58 is connected to the wing tip device, further rotation of the wing tip device, angles the panel 34 and draws the panel 34 back towards the shielding position.

[0080] The movement of the wing tip device from the ground configuration to the flight configuration is essentially the reverse of the motion described above. The linkage assembly 50 is particularly beneficial in that during the final stages of movement to the flight configuration the panel 34 is lowered into place thereby creating the seal along the sealing arrangement 17 with the surrounding structure and locating the panel 34 flush with the upper surface 30, 26 of the wing. The linkage assembly 50 is also configured to pull the panel 34 down against the seal to create robust sealing pressure when the wing tip device 12 is in the flight configuration.

[0081] A second embodiment of the invention is shown in Figures 3a and 3b. The wing tip, fixed wing and hinge is similar to the previous embodiment, but the panel 134 has the -17 -differences described below. Like features are described with the same reference numerals as the embodiment in Figure 2a-2b, but incremented by 100.

[0082] In the second embodiment, the wing 110 comprises an actuation mechanism 111 comprising a geared rotary actuator GRA (not fully visible in the Figures) and a curved toothed rack 140. The GRA has an output shaft onto which a pinion gear 138 is mounted.

The pinion gear 138 is coupled, via a secondary gear 139, to the curved rack 140. The curved rack 140 includes a support structure which is fixedly attached to a root of the wing tip device 112 via a pair of lugs 144. The GRA is arranged to drive the rack 140 in a curved path to move the wing tip device 112 between the flight configuration and the ground configuration.

[0083] The GRA rotates the pinion 138 such that the rack is rotated outboard, thereby moving the wing tip device 112 such that it rotates about the hinge axis 118.

[0084] In the second embodiment, the panel 134 does not extend as far as the interleaving lugs 120 of the hinge (although in principle it could do so). Instead, the panel 134 covers the actuator mechanism 111 and the region between the pair of interleaving lugs 120.

[0085] The panel 134 is connected to the fixed wing 114 by a linkage assembly 150 comprising a fixed wing link 152 that is pivotably mounted at a pivot 154 on the fixed wing and a pivot 156 on the underside of the panel.

[0086] The wing tip device is connected to the panel 134 at a pivoted connection 180. As the wing tip device 112 rotates, it exerts an motive force on the panel 134 via connection 180. The linkage assembly 150 ensures the panel 134 is lifted (by virtue of the motive force) away from the upper surface of the wing and the panel 134 is separated from the surrounding structure along its whole perimeter. By virtue of the connection 180 to part of the wing tip device 112, the panel 134 is passively actuated and does not requires its own actuation assembly.

[0087] In the second embodiment of the invention, an edge 134a of the panel 134 adjoins the upper cover 126 of the wing tip device along an interface. The interface is arranged such that an edge 126a of the upper cover (of the wing tip device) overlaps the adjoining edge 134a of the panel 134 along an overlap region 182 (not visible in the Figures). As the wing tip device 112 rotates from the flight configuration to the ground configuration, -18 -the upper cover 126 is separated from the panel 134 along the overlap region. In the reverse motion as the wing tip device approaches the ground configuration, the overlap may ensure the panel 134 is firmly held in place by the overlapping edge 126a of the wing tip device cover 126.

[0088] A third embodiment is shown in Figures 4a to 4c The wing tip, fixed wing and hinge is similar to the embodiment in Figure 2a-2b, but the panel has the differences described below. Like features are described with the same reference numerals as the embodiment in Figure 2a-2b, but incremented by 200.

[0089] In the third embodiment, the panel 234 does not extend as far as the interleaving lugs of the hinge (although in principle it could do so). Instead, the panel 234 covers the region above the actuator mechanism 211.

[0090] The panel 234 is connected to the fixed wing 214 by a track and follower arrangement comprising a curved track 290 and a pair of arms 288 (followers) The panel 234 comprises the pair of arms 288 the distal end of which is received in the curved track 290 such that each arm 288 is constrained to move along the respective track 290. [0091] The edge 234a of the panel 234 is linked to the edge 226a of the wing tip cover 226 at connection 280. As the wing tip device 212 rotates, it exerts an motive force on the panel 234 via connection 280. The track 290 ensures the panel 234 is lifted away from the upper surface of the wing and the panel 234 is separated from the surrounding structure along its whole perimeter. As shown in Figures 4b and 4c, as the panel 234 is pushed back, the follower moves along the track and the shape of the track ensures the panel is lifted away from the upper surface of the wing and the panel is separated from the surrounding structure along its whole perimeter. By virtue of the connection 280 to part of the wing tip device 212, the panel 234 is passively actuated and does not requires its own actuation assembly.

[0092] In reverse (from ground to flight configuration) the connection 290 pulls the panel 234 back along the track and into place to form a seal around its perimeter.

[0093] Whilst the present invention has been described and illustrated with reference to particular embodiments, it will be appreciated by those of ordinary skill in the art that the invention lends itself to many different variations not specifically illustrated herein.

-19 - [00941 Where in the foregoing description, integers or elements are mentioned which have known, obvious or foreseeable equivalents, then such equivalents are herein incorporated as if individually set forth. Reference should be made to the claims for determining the true scope of the present invention, which should be construed so as to encompass any such equivalents. It will also be appreciated by the reader that integers or features of the invention that are described as preferable, advantageous, convenient or the like are optional and do not limit the scope of the independent claims. Moreover, it is to be understood that such optional integers or features, whilst of possible benefit in some embodiments of the invention, may not be desirable, and may therefore be absent, in other embodiments.

Claims

-20 -CLAIMS1. An aircraft wing, the aircraft wing comprising a fixed wing and a wing tip device rotatable about a hinge at the tip of the fixed wing, wherein the wing tip device comprises a moveable element that moves along a path, relative to stationary structure at the tip of the fixed wing, when the wing tip device is rotated about a hinge axis of the hinge, between: (i) a flight configuration for use during flight and (ii) a ground configuration for use during ground-based operations, in which ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced, wherein the wing further comprises a panel at the boundary between the wing tip device and the fixed wing, and the wing is arranged such that: in the flight configuration the panel is in a closed position such that the panel is substantially flush with the upper surface of the wing, and the panel is located in the path of the moveable element; during initial movement from the flight configuration to the ground configuration the panel is lifted away from the upper surface of the wing, thereby separating the panel from the upper surface of the wing and; in the ground configuration, the panel is in a position outside the path of the moveable element such that clashing of the moveable element with the stationary structure at the tip of the fixed wing is avoided.
2. A wing according to claim 1, further comprising a sealing arrangement for creating a seal between the panel and the surrounding structure of the fixed wing and wing tip device when the wing tip is in the flight configuration, wherein the seal is created along substantially the whole perimeter of the panel.
-21 - 3. A wing according to any preceding claim, wherein the hinge comprises a plurality of lugs of the wing tip device interleaving a plurality of lugs on the fixed wing, the plurality of lugs on the wing tip device being rotatable about the hinge axis relative to the plurality of lugs on the fixed wing.
4. A wing according to claim 3, wherein the panel is arranged such that in the flight configuration the panel covers the interleaving lugs when the wing tip device is in the flight configuration.
5. A wing according to any preceding claim, wherein the panel is coupled to the fixed wing via a linkage assembly.
6. A wing according to claim 5, wherein the linkage assembly comprises a fixed-wing link, the fixed-wing link being pivotably mounted at one end, about a first pivot on the fixed wing, and being pivotably mounted at the other end about a second pivot on the panel.
7. A wing according to claim 6, wherein the linkage assembly further comprises a driver arm link, the driver arm link being pivotably mounted to the wing tip device at one end, and being pivotably mounted to the fixed-wing link at the other end.
8. A wing according to claim 7, wherein the linkage assembly further comprises a secondary link, the secondary link being pivotably mounted at one end to the driver arm link, and being pivotably mounted at the other end to the panel.
9. A wing according to claim 8, wherein the secondary link is pivotably mounted to the driver arm link at a location between the pivot of the driver arm on the wing tip device and the pivot of the driver arm on the fixed-wing link, and wherein the secondary link is pivotably mounted to the panel at a location outboard of the pivot of the fixed-wing link on the panel.
-22 - 10. A wing according to any of claims 6 to 9, wherein the linkage assembly is configured such that when the wing tip device is in the ground configuration, the panel is positioned to shield the hinge.
I I. A wing according to claim 10, wherein the panel is positioned at an incline and extends between a location on the fixed wing upper cover inboard of the hinge axis, to a location on the wing tip device outboard on the hinge axis.
12. A wing according to any preceding claim, wherein the panel comprises a follower that is constrained to move along a track, and wherein the track is shaped such that during initial movement from the flight configuration to the ground configuration the panel is lifted away from the upper surface of the wing, thereby separating the panel from the upper surface of the wing and in the ground configuration, and such that the panel is in a position outside the path of the moveable element such that clashing of the moveable element with the stationary structure at the tip of the fixed wing is avoided.
13. A wing according to any preceding claim, wherein the movement of the panel is effected by movement of the wing tip device.
14. A wing according to claim 13, wherein the panel is linked to the wing tip device such that the movement of the panel is effected by the movement of the wing tip device.
15. A wing according to any preceding claim, wherein the wing further comprises an actuation mechanism for moving the wing tip device from the flight configuration to the ground configuration, and the actuation mechanism comprises the moveable element.
16. A wing according to claim 15, wherein the actuation mechanism comprises a rotary drive, the rotary drive being arranged to drive the moveable element in a curved path to move the wing tip device between the flight configuration and the ground configuration.
-23 - 17. A wing according to claim 16, wherein the rotary drive comprises a pinion, and the moveable element comprises a curved rack for being driven along a curved path by rotation of the pinion.
18. A wing according to any preceding claim, wherein the wing tip device comprises an upper cover and in the flight configuration the upper cover of the wing tip device adjoins the panel along an interface, the interface being arranged such that an edge of the upper cover overlaps the adjoining edge of the panel along an overlap region.
19. A wing according to any preceding claim, wherein the tip of the fixed wing comprises a wing box having a pair of ribs, a pair of spars and an upper and lower cover, and wherein the root of the wing tip device comprises wing tip box, comprising a pair of wing tip spars, a pair of wing tip ribs and a wing tip upper cover and a wing tip lower cover, and wherein when the wing tip is in the flight configuration, the upper and lower covers of the wing tip box are continuations of the upper and lower covers of the wing box, and in the flight configuration the panel is flush with the adjoining upper covers.
20. A wing according to claim 19 when dependent on claim 16, wherein the rotary drive is housed in the wing box of the fixed wing.
21. A method of moving a wing tip device from a flight configuration for use during flight, to a ground configuration for use during ground-based operations, in which ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced, the method comprising the steps of having a panel in a closed position in which the panel is located in the path of a moveable element of the wing tip device, and is substantially flush with the upper surface of the wing, -24 -lifting the panel away from the upper surface of the wing, thereby separating the panel from the upper surface of the wing and; continuing to move the panel such that in the ground configuration, the panel is in a position outside the path of the moveable element such that clashing of the moveable element with the stationary structure at the tip of the fixed wing is avoided.
22. A method according to claim 21, wherein in the closed position the perimeter of the panel surrounds a hinge structure thereby covering the hinge structure, and the step of separating the panel from the upper surface of the wing exposes the hinge structure.
23. A folding wing tip arrangement for an aircraft wing, the arrangement comprising a fixed wing and a hinged wing tip device at the tip thereof, the wing tip device being configurable by a wing tip actuator between: (i) a flight configuration for use during flight and (ii) a ground configuration for use during ground-based operations, in which ground configuration the wing tip device is moved away from the flight configuration such that the span of the aircraft wing is reduced, wherein the arrangement comprises a moveable panel covering the hinge structure of the wing tip device, and wherein the panel is mounted on a linkage assembly, the linkage assembly spanning the fixed wing and the wing tip device such that movement of the wing tip device effects movement of the linkage assembly, and wherein the linkage assembly is arranged such that during movement of the wing tip device from the flight to the ground configuration, the panel is initially lifted up and away from the upper surface of the wing, to expose the hinge and to allow movement of the wing tip device to the ground configuration without clashing.-25 -
24. An arrangement according to claim 23, wherein the linkage assembly is further arranged such that in the ground configuration, the panel is in a shielding position between the fixed wing and folded wing tip, thereby shielding the hinge structure from above.