Landing gear assembly

Abstract

A retractable, fuselage-mounted landing gear assembly is disclosed. The landing gear assembly includes a main strut, a drag strut, and a landing gear main fitting. A first end of the drag strut is attached to the main strut and a second end of the drag strut is connected to the fuselage. A first end of the landing gear main fitting is attached to the main strut and a second end of the main fitting is connected to the fuselage. When the landing gear is deployed, substantially all of the landing gear load is transferred from the landing gear to the fuselage via one or more of the drag strut and the main fitting.

Description

Background Technology

[0001] This invention relates to aircraft landing gear. More specifically, but not exclusively, this invention relates to: an aircraft including landing gear mounted to the fuselage via a tow strut and landing gear main assembly; landing gear suitable for use in such an aircraft; and a method for retracting such landing gear.

[0002] The positioning of an aircraft's main landing gear depends largely on the need to ensure stability during taxiing, takeoff, and landing.

[0003] When the landing gear load is transferred from the landing gear to the rest of the aircraft, significant loads are borne at the attachment points between the landing gear and the frame. Additional structural reinforcement is typically required in these areas to allow the frame to support the landing gear load. Providing such reinforcement can increase the weight of the aircraft. Therefore, it is advantageous to provide a landing gear that reduces the amount of additional structural reinforcement required on the aircraft.

[0004] For wings using composite materials, such as carbon fiber reinforced polymer (CFRP) wings, handling the landing gear loads at the attachment point to the frame presents a unique challenge due to the anisotropic nature of these materials. For example, CFRP materials can withstand higher loads along the fiber length but may require significant reinforcement to accommodate off-axis loads. Therefore, when fabricating the same structure using composite materials, loads that can be accommodated by a metal structure may require additional reinforcement. This can further increase the structural weight and / or cause manufacturing difficulties when attempting to lay very thick or complex-shaped areas of composite materials. The need for a structure necessary to accommodate landing gear loads within the wing also constrains the shape of the wing that can be used when the landing gear is mounted on the wing. Therefore, it is advantageous to provide landing gear that reduces the landing gear load transmitted to the wing without adversely affecting the stability of the aircraft during taxiing, takeoff, and landing.

[0005] One existing method for reducing the load at any one attachment point is to provide a landing gear that transfers the load to the aircraft through multiple attachment points, including points located on both the wing and fuselage. EP 0 031 602 describes such a landing gear that is attached to the aircraft at four points: two trunnion bearings at the top of the main strut attaching the landing gear to the wing, a trailing strut attaching the landing gear to the wing / body, and a side strut. Although this four-point structure can partially reduce the load, a considerable off-axis load is still transferred to the wing. In particular, when the trailing load is transferred to the wing via the two trunnion bearings (also known as the front and rear rudder pins), this generates a considerable bending moment between the two trunnion connections in the wing.

[0006] Typically, modern landing gear retracts immediately once an aircraft is in flight. Space is scarce within the aircraft's fuselage, particularly in the wings, making it desirable for landing gear to retract into a compact configuration. However, many multi-attachment landing gear systems are not particularly compact when retracted and / or are mechanically complex, increasing manufacturing and / or maintenance costs. It would be advantageous to provide a mechanically simpler landing gear that reduces the maximum load on the attachment points while minimizing the space it occupies in the wings when retracted.

[0007] This invention seeks to alleviate one or more of the aforementioned problems. Alternatively or additionally, this invention seeks to provide an improved landing gear. Summary of the Invention

[0008] According to a first aspect, the present invention provides an aircraft comprising a fuselage and a landing gear assembly (also referred to herein as landing gear) mounted on the fuselage. The landing gear assembly may include a main strut. The landing gear assembly may include a tow strut, a first end of which is attached to the main strut. A second end of the tow strut may be connected to the fuselage, such that landing gear loads can be transferred from the tow strut to the fuselage of the aircraft. The landing gear assembly may include a landing gear main assembly. A first end of the main assembly may be attached to the main strut. A second end of the main assembly may be connected to the fuselage, such that landing gear loads can be transferred from the landing gear main assembly to the fuselage of the aircraft. In use, when the landing gear is in a deployed configuration, substantially all of the landing gear loads can be transferred from the landing gear to the fuselage via one or more of the tow strut and the main assembly.

[0009] The landing gear according to the invention allows landing gear loads to bypass the wing, thereby allowing for greater design freedom in wing shape. Further providing a landing gear connected to the fuselage via a tow strut and main landing gear assembly allows the main strut to be positioned behind the wing and / or outside the fuselage frame when the landing gear is deployed, thereby providing stability during taxiing, takeoff, and / or landing.

[0010] Landing gear loads can be defined as the drag loads, lateral loads, and vertical loads experienced by the landing gear when it is deployed. The landing gear can be arranged such that substantially all of these loads experienced by the landing gear are transmitted to the aircraft via the tow struts and main components.

[0011] Each of the tow strut and the main assembly can be connected to the aircraft to transfer landing gear loads from the landing gear to the aircraft. Each of the tow strut and the main assembly can provide a landing gear load path between the main strut and the relevant point of attachment to the aircraft. Therefore, the landing gear can be configured to have: two basic landing gear load paths through which the landing gear load is transferred to the aircraft; a tow strut load path; and a main assembly load path. The tow strut and the main landing gear assembly can be connected to the aircraft without passing through the wing. Therefore, the landing gear load can be transferred to the fuselage by the tow strut and the main landing gear assembly, thus bypassing the wing.

[0012] The landing gear can be retractable. The landing gear can be mounted to move relative to the fuselage of the aircraft between a deployed configuration (e.g., for taxiing, takeoff, and / or landing) and a retracted configuration (e.g., for cruise). When the landing gear is in the deployed or retracted configuration, the main strut can be said to be in the deployed or retracted position relative to the fuselage of the aircraft.

[0013] An aircraft may include a wing. A wing may include one or more spars—such as a rear sparb—and / or one or more ribs. When the struts are in the deployed position, the main strut may be located behind the rear sparb, and optionally, behind the wing, for example, at the trailing edge of the wing. The spanwise location of the main strut may be behind the rear sparb / wing. For example, if the rear sparb and / or the wing is not parallel to the lateral axis of the aircraft, the main strut need not be located behind the rearmost part of the sparb / wing; it is sufficient for the area of ​​the main strut to be located behind the sparb / wing.

[0014] The fuselage may include a frame (e.g., the mechanical structure of the fuselage), on which, for example, any fairing may be mounted. When the struts are in the deployed position, the main struts may be located outside the frame. Positioning the main struts of the landing gear behind the wings and / or outside the fuselage allows for good stability during taxiing, takeoff, and / or landing. The aircraft may include one or more fairings arranged to streamline the landing gear in deployed and / or retracted configurations. For example, the aircraft may include a ventral fairing arranged to streamline at least a portion of the main landing gear components when the landing gear is deployed.

[0015] The second end of the tow strut can be connected to a point located on or within the fuselage, such as a point on or within the fuselage frame. The second end of the tow strut can also be connected to the fuselage in the area where the wing connects to the fuselage. For example, the second end of the tow strut can be connected to a point adjacent to the wing, such as adjacent to the wing's rear spars and / or located behind the wing's rear spars. The second end of the tow strut can also be connected to the frame structure that connects the wing and fuselage. The area where the wing connects to the fuselage is already highly reinforced, and therefore, less additional structural reinforcement may be required when the landing gear load is transferred to the aircraft in this area. Therefore, connecting the landing gear to the fuselage in the area adjacent to the wing reduces the need for structural reinforcement and thus reduces the weight of the aircraft. The second end of the tow strut can be connected to a point spaced from the wing, for example, the wing's rear spars (along the aircraft's vertical and / or longitudinal axes), at a distance not exceeding 10% of the wing's root chord length, or for example, not exceeding 5% of the wing's root chord length. The second end of the tow strut can be connected to a structural portion of the wing, positioned on or within a shell defined by the fuselage frame. Ribs (sometimes referred to as 'Rib 1') can intersect the fuselage at the point where the wing connects to it. The second end of the tow strut can be connected to Rib 1. Rib 1 is a particularly reinforced area of ​​the aircraft, and therefore, connecting the tow strut here further reduces the need for any structural reinforcement.

[0016] A tow strut can be configured to transfer most of the tow load borne by the landing gear to the aircraft. The tow strut can be configured such that its length can vary as the main strut moves between a deployed and retracted position; for example, the tow strut can be a folding tow strut or a telescopic tow strut. A folding tow strut can include two or more components pivotally connected to each other. One end of a first component can be attached to the fuselage. One end of a second component can be mounted to the main strut. The first and second components can be pivotally connected at a second end of the first component and a second end of the second component. The landing gear assembly can include a locking member configured to prevent pivoting of the components relative to each other when the locking member is engaged. The tow strut can be pivotally connected to the fuselage and / or the main strut such that the tow strut can rotate about its longitudinal axis (which is the longitudinal axis of the tow strut when the landing gear is in the deployed configuration) during landing gear retraction. Having a variable length and / or roll of the tow strut can facilitate landing gear retraction to a compact configuration.

[0017] The tow strut can extend forward of the main strut and / or inward from the main strut. Therefore, the second end of the tow strut can be positioned forward of and / or inward of the first end of the tow strut. When the main strut is in the deployed position, the point where the tow strut connects to the fuselage can be positioned forward of and / or inward of the main strut. The tow strut can be connected to a support structure attached to the aircraft fuselage, such as to a frame, for example, to Rib 1.

[0018] The landing gear main assembly can be connected to the fuselage via a fuselage main assembly attached to the fuselage. This fuselage main assembly may include a main beam connected to and attached to the fuselage. The fuselage main assembly may include multiple support members, such as rods, connected at one end to the main beam and attached at the other end to the fuselage, for example, to a frame attached to the fuselage. Therefore, at least a portion of the landing gear load transferred from the landing gear main assembly to the main beam can be transferred to the fuselage via the support members. The arrangement of the main beam and multiple support members allows for a reduction in the amount of material (and therefore the weight) of the main assembly, i.e., allows the amount of material in each member and / or beam to be reduced to the minimum required to resist loads in each given direction. Additionally or alternatively, having such a main assembly allows for multiple points of connection to the fuselage and / or allows these points to move to areas of structural strength—via which the main assembly is connected to the fuselage—thereby reducing the need for additional reinforcements.

[0019] The aircraft may include bulkheads, such as pressure bulkheads, rear pressure bulkheads, or aft pressure bulkheads. Landing gear main components may be connected to the fuselage via bulkheads. For example, fuselage main components, such as main beams, may be attached to the fuselage at a bulkhead, or, for example, attached to the fuselage via a bulkhead. In addition to components required in the fuselage before landing gear is installed, the fuselage may also include one or more reinforcing members, such as struts, struts, and / or ribs. These reinforcing members may be configured to resist loads exerted on the fuselage by the landing gear, such as fuselage main components, and / or tow struts.

[0020] The landing gear main assembly can be pivotally connected to the fuselage, for example, to the fuselage main assembly, for rotation about the landing gear axis, allowing the main strut to rotate between an extended and retracted position. The landing gear main assembly and the fuselage main assembly can be hingedly connected to allow rotation about a single axis—the landing gear axis. One of the landing gear main assembly and the fuselage main assembly (e.g., the distal end of the main beam, i.e., the end of the main beam positioned further from the fuselage) may include a rudder pin, while the other includes a rudder pivot, such that the rudder pin and rudder pivot together form a hinge. Alternatively, other forms of hinges may be used.

[0021] The landing gear axis can be tilted relative to the longitudinal and / or lateral axes of the aircraft. A tilted landing gear axis can facilitate landing gear retraction into the fuselage by providing improved retraction kinematics. For example, by varying the tilt relative to both the longitudinal and lateral axes during the design process, the position of the distal end of the main strut (and any wheels mounted on that distal end) when the landing gear is in the retracted configuration can be altered to account for available space in the aircraft. The landing gear axis can be tilted relative to both the lateral and longitudinal axes of the aircraft, such that the distal end of the main strut moves inward and forward as the main strut rotates between the deployed and retracted positions. The landing gear axis can be tilted relative to the vertical axis of the aircraft, for example, substantially perpendicular to the vertical axis, such that the distal end of the main strut moves upward as the main strut rotates between the deployed and retracted positions. The distal end of the main strut can be defined as the end of the main strut furthest from the fuselage when the main strut is in the deployed position (and / or the landing gear is in the deployed configuration).

[0022] The landing gear axis may be tilted at least 10 degrees, for example at least 15 degrees, or for example at least 20 degrees, relative to one or both of the lateral and longitudinal axes. The angle given herein refers to the size of the acute angle formed between the landing gear axis and the lateral or longitudinal axis. The landing gear axis may be tilted at approximately 45 degrees relative to the longitudinal and lateral axes of the aircraft. The landing gear axis may be positioned closer to the proximal end of the main strut than to the distal end of the main strut. The proximal end of the main strut may be defined as the end of the main strut closest to the fuselage when the main strut is in the deployed position and / or the landing gear is in the deployed configuration. The landing gear axis may be positioned in the region of the proximal end of the main strut. A tow strut may be attached to the main strut and is closer to the distal end of the main strut than to the landing gear axis.

[0023] The landing gear may include a wheel assembly mounted at the distal end of the main strut. The wheel assembly may include, for example, a pair of wheels arranged in a diabolo pattern. The wheel assembly may include multiple additional pairs of wheels; for example, the wheel assembly may include a bogie with two or more pairs of wheels.

[0024] When the landing gear is in the retracted configuration, at least a portion, such as most or substantially all, of the wheel assembly can be received within the fuselage / fuselage frame, for example, within a recess, or within a landing gear bay defined within the fuselage / fuselage frame. The landing gear axis may be tilted relative to the lateral and / or longitudinal axes of the aircraft, such that the distal end of the main strut moves inward, forward, and upward as the main strut moves from the deployed position to the retracted position, thereby allowing the wheels to move into the landing gear bay. The aircraft may include one or more landing gear bay doors arranged to cover the landing gear bay when the aircraft is in flight. The landing gear bay may be located in an area aft of the wing, for example, in an area aft of the wing spars.

[0025] The aircraft may be a commercial airliner (for the purposes of this application, the term commercial airliner is also considered to include aircraft of the same type configured for cargo transport), for example, an aircraft capable of transporting more than 50, for example, more than 100 passengers. The aircraft may be a low-wing aircraft (i.e., in which the wing root is located at or below the point where the fuselage is widest).

[0026] The main strut can be the main leg of the landing gear. The main strut can be configured to transport loads from wheels (if present) to the landing gear main assembly and / or tow bar. The main strut can include a shock absorber, such as a housing comprising a shock absorber. The landing gear main assembly can be integrally formed with the main strut, such as integrally formed with the housing of the shock absorber.

[0027] The aircraft may also include a nose landing gear. The aircraft may include a first landing gear assembly and a second landing gear assembly as described above, with one landing gear assembly located on each side of the fuselage. The two landing gear assemblies may form part of the aircraft's main landing gear assembly. The aircraft may not include a wing-mounted landing gear assembly.

[0028] An aircraft may have a vertically extending vertical (yaw or normal) axis. An aircraft may have a lateral (lateral or pitch) axis extending across its width. An aircraft may have a longitudinal (or roll) axis extending along its length. As used herein, "forward" means that an element is positioned closer to the front of the aircraft (i.e., the nose) along its longitudinal axis, while "rearward" means that an element is positioned further away from the front of the aircraft (i.e., the nose) along its longitudinal axis. "Outward" means that an element is closer to the wingtip / further from the centerline of the aircraft along its lateral axis (or along its wingspan), while "inward" means that an element is closer to the centerline / further from the wingtip.

[0029] According to a second aspect of the invention, a landing gear assembly is also provided, comprising a main strut having at least one pair of wheels mounted at a first end, each pair of wheels being arranged to rotate about a wheel axis. The landing gear assembly may further include a tow strut, a first end of which is attached to the main strut and a second end of which is configured for connection to the fuselage of an aircraft. The landing gear assembly may further include a main fitting for connecting the landing gear to the aircraft fuselage, the main fitting being attached to the main strut and defining a pivot axis about which the main strut can rotate, for example, when moving between a deployed configuration and a retracted configuration. The pivot axis may be neither parallel nor perpendicular to the axis of each wheel.

[0030] According to a third aspect of the invention, an aircraft is also provided, having a fuselage and a landing gear assembly according to a second aspect, wherein a second end of a tow strut and a main fitting are connected to the fuselage of the aircraft. As described above, the pivot (or landing gear) axis can be tilted relative to both the longitudinal axis and the lateral axis of the aircraft. The pivot (or landing gear) axis can be tilted relative to the vertical axis of the aircraft.

[0031] According to a fourth aspect of the invention, a method is provided for retracting a landing gear assembly mounted on an aircraft, the aircraft including a fuselage having a frame, the landing gear assembly including a main strut connected to the fuselage via a tow strut and a main fitting, the method comprising the steps of: rotating the main strut about a landing gear axis to move the landing gear from an deployed configuration to a retracted configuration.

[0032] In the deployed configuration, the main strut (and any wheel assembly mounted on the main strut) can be positioned outside the fuselage frame and / or behind the rear wing spars of the wing.

[0033] The fuselage may include recesses defined within the fuselage, such as landing gear bays. In a retractable configuration, at least a portion of the landing gear wheel assembly may be received in the recess.

[0034] Rotation of the main strut about the landing gear axis can cause the distal end of the main strut (and any wheel assembly mounted on the main strut) to move forward, upward, and inward, for example, so that the wheel assembly (or part of the wheel assembly) can be received in a recess.

[0035] As the landing gear moves from a deployed configuration to a retracted configuration, the length of the tow strut can change, for example, decrease (and as the landing gear moves from a retracted configuration to a deployed configuration, the length of the tow strut can change, for example, increase). The tow strut can fold as the landing gear moves from a deployed configuration to a retracted configuration. The tow strut can unfold as the landing gear moves from a retracted configuration to a deployed configuration. The tow strut can rotate (or roll) about its longitudinal axis as the landing gear moves between the deployed and retracted configurations.

[0036] When the landing gear moves from deployed configuration to retracted configuration (and / or from deployed configuration to retracted configuration), the landing gear main assembly (and therefore the main strut) can pivot about the fuselage main assembly, for example, about the outer end of the fuselage main assembly, for example, about the outer end of the main beam.

[0037] According to a fifth aspect of the invention, an aircraft is provided, comprising one or more of the following: a fuselage having a frame; two main landing gear assemblies, each mounted on the fuselage, one main landing gear assembly mounted on each side of the fuselage, each main landing gear assembly including a main strut connected to the fuselage via a tow strut and a main fitting; and two wings, each wing having a rear spars. In use, when the main landing gear assemblies are in a deployed configuration relative to the fuselage, the main struts can be positioned on the outer side of the frame and behind the rear spars of the wings. The aircraft may also include a nose landing gear assembly.

[0038] Of course, it should be understood that the features described with reference to one aspect of the invention can be incorporated into other aspects of the invention. For example, the method of the invention can be combined with any features described with reference to the device of the invention, and the device of the invention can be combined with any features described with reference to the method of the invention. Attached Figure Description

[0039] Embodiments of the invention will now be described by way of example only with reference to the accompanying schematic diagrams, in which:

[0040] Figure 1 A perspective view of an aircraft including a landing gear according to a first exemplary embodiment of the present invention is shown;

[0041] Figure 2 It shows Figure 1 A close-up view of a part of the aircraft;

[0042] Figure 3 It shows Figure 1 and Figure 2 A close-up view of the landing gear;

[0043] Figure 4 It shows Figure 1 A rear view of a portion of the aircraft;

[0044] Figure 5 shows the landing gear configurations when it is in (a) deployed and (b) retracted. Figure 1 A partial bottom plan view of the aircraft; and

[0045] Figure 6 shows the landing gear configurations when it is in (a) deployed and (b) retracted. Figure 1A side view of a portion of the aircraft.

[0046] Figure 7 It shows Figure 1 , Figure 2 and Figure 3 A close-up view of the landing gear connection. Detailed Implementation

[0047] Figure 1 An aircraft 1 is shown, having a fuselage 2, two wings 4 mounted on the fuselage 2, a tail assembly 6, and a nose landing gear 8. The aircraft 1 also includes two main landing gears 10 (hereinafter referred to as 'landing gears') according to a first exemplary embodiment of the invention. One landing gear 10 is mounted on each side of the fuselage 2. A belly fairing 12 extends around the lower part of the fuselage 2, thereby streamlining the elements of the landing gear 10 located at the points where the landing gear 10 connects to the fuselage 2.

[0048] Figure 2 It shows Figure 1 A close-up of a portion of the aircraft 1 and its landing gear 10. The landing gear 10 is... Figure 2 It is in an deployed configuration (i.e., a configuration for landing and / or taxiing). It should be understood that, in Figure 2 The fuselage 2 and wing 4 are shown schematically at a height. Arrows A and B indicate forward and outward directions, respectively. A landing gear bay 14 is formed in the fuselage 2 behind the wing 4. The landing gear 10 includes a main strut 16 with two wheels 18 mounted at its distal end. Figure 2 In this configuration, the wheels are arranged in a so-called 'diablo' configuration. In other embodiments, a bogie comprising more than two wheels may be used. A tow strut assembly 20 is connected at one end to the main strut 16 and extends forward and inward. The other end of the tow strut assembly 20 is attached to a bracket 22, which is attached to the fuselage 2 at a point located aft of the root 24 of the wing 4 and forward of the landing gear bay 14. The landing gear main assembly 26 (hereinafter referred to as the 'LG main assembly') is attached to the main strut 16 and to the fuselage main assembly assembly 28 (hereinafter referred to as the 'F main assembly'), which is attached to the fuselage 2 at a point located aft of the landing gear bay 14. In some embodiments, the tow strut 20 may (e.g., via a bracket to which it is attached) be connected to a rib of the wing, which forms a joint between the fuselage and the wing, sometimes referred to as a 'Rib 1'. Since the rib is located on the outer shell defined by the fuselage, for the purposes of this invention, the rib can be considered as forming part of the fuselage. Similarly, in some embodiments, the tow strut can be attached to a structure located within the outer shell of the fuselage, such as a wing box, but sometimes it can be considered as forming part of the wing structure.

[0049] Figure 3 It shows Figure 1 and Figure 2 A close-up of the landing gear 10, again, the landing gear 10 is in an deployed configuration. The support 22 includes a rudder pivot 23. The tow strut assembly 20 includes a folding tow strut 30 having two tow strut members 32 pivotally connected to each other at a first end. One of the tow strut members 32a is pivotally connected to the support 22 at the other end via a rudder pin 25, which is attached to the end of the tow strut member 32a and received in the rudder pivot 23 about an axis (by...). Figure 3 (The dashed line marked C in the diagram indicates rotation.) Another tow strut member 32b is pivotally mounted to the main strut 16. The tow strut assembly 20 also includes a locking member 34 and a locking actuator 36, the locking member 34 extending between the main strut and the tow strut member 32b, and the locking actuator 36 mounted on the tow strut member 32a and connected to the locking member 34.

[0050] Still refer to Figure 3 The LG main component 26 defines a rudder pin 26a, which connects to a corresponding rudder pivot 28a formed on the F main component 28 to form a hinge, the hinge having a... Figure 3 The axis of rotation (hereinafter referred to as the 'landing gear axis') is indicated by the dashed line marked 50. The landing gear axis 50 is not parallel to either the longitudinal axis or the lateral axis of the aircraft 1. The main assembly 28 includes a main beam 38 and a plurality of rods 40, the main beam 38 having a rudder pivot 28a formed thereon, and the plurality of rods 40 extending between the main beam 38 and the fuselage 2. The main assembly 28 is mounted to the fuselage 2 at a rear pressure bulkhead 42, which... Figure 3 The middle part is indicated by a dashed line. In other embodiments, the main accessory 28 can be installed to the fuselage 2 at different locations.

[0051] Also refer to Figure 7 The LG main assembly 26 is typically located inside the main strut 16 and includes a beam 70 that is generally parallel to the landing gear axis 50 and connects to the top of the main strut at one end. The LG main assembly 26 also includes a support 72 connected to the distal end of the beam 70 and further down the main strut 16 to provide proper structural support to the beam 70. A rudder pin 26a is provided on the top of the beam 70 via a series of protrusions 74a, 74b. The main assembly 28 has a rudder pivot 28a formed by a complementary series of protrusions 76a, 76b, 76c.

[0052] The first LG protrusion 74a is seated between the first F protrusion 76a and the second F protrusion 76b, and is connected to the first F protrusion 76a and the second F protrusion 76b by a pin. The second LG protrusion 74b is integrally formed with the support member 72 and has a protruding pin that is received in the third F protrusion 76c and extends slightly beyond the third F protrusion 76c. The connection between the LG main fitting 26 and the F main fitting 28 can be of any suitable type to provide rotation about the landing gear axis 50. Any combination of lugs, pins, rudder pins, and rudder pivots is suitable. Either the LG main fitting 26 or the F main fitting 28 can, where appropriate, carry the rudder pin and / or rudder pivot. Combinations of connection features can be used in any number to provide suitable characteristics to the connection.

[0053] In operation, the landing gear load is transmitted to the aircraft via the tow strut assembly 20 and the LG main component 26. Therefore, for the landing gear according to this embodiment, all landing gear loads are transmitted to the aircraft at the fuselage 2, bypassing the wing 4. The fuselage requires less additional reinforcement than the wing required to respond to the same landing gear load, thus reducing the aircraft weight. Furthermore, the space within the fuselage for additional reinforcement is less constrained than that within the wing, facilitating the integration of the landing gear into the aircraft. Specifically, in this embodiment, the tow strut assembly 20 is connected to the aircraft in the area where the wing 4 connects to the fuselage 2. The area where the wing 4 connects to the fuselage 2 is already highly reinforced, and therefore, less additional reinforcement is needed to handle the landing gear load transmitted via the tow strut assembly 20.

[0054] The combination of the tow strut assembly 20 and the LG main accessory 26 provides a mechanically simpler method for body-mounting landing gear. This arrangement also improves kinematic performance, allowing the landing gear 10 to be stored in the landing gear bay 14 formed within the fuselage 2, as described below. Figure 3 The discussion will proceed in more detail in Figure 6.

[0055] Using an F-main assembly 28 comprising a main beam 38 and multiple rods 40 can advantageously reduce the amount of material in the F-main assembly (and thus reduce its weight), which is achieved by allowing the amount of material in each rod and / or beam to be reduced to the minimum required to respond to the relevant load vector. Additionally or alternatively, having an F-main assembly 28 comprising a main beam 38 and multiple rods 40 can allow for multiple points of connection to the fuselage and / or allow these points to be located in areas of structural strength—via which the F-main assembly 28 is connected to the fuselage—thus reducing the need for additional reinforcement.

[0056] like Figure 7As shown, the main beam 38 can be formed as a web or skeletonized to further reduce the weight of the F main assembly by further reducing the amount of material required. Multiple bars 40 are connected to the main beam 38 near the F main assembly 28, thereby reducing the load the main beam 38 will have to bear. Therefore, a large portion of the main beam 38 can be web-based or "skeletonized" to further reduce the weight of the assembly. As shown in the figures, the bars can be non-uniformly distributed around the main beam 38, for example, having more bars on the side of the landing gear away from the tow strut assembly 20 to improve resistance to forces in other directions.

[0057] Figure 4 It shows Figures 1 to 3 The rear view of the aircraft 1 and landing gear 10, with the landing gear in the deployed configuration.

[0058] Figures 5(a) and (b) show the configurations in the unfolded and retracted configurations, respectively. Figures 1 to 4 Plan view of landing gear 10.

[0059] Figures 6(a) and (b) show the configurations in the unfolded and retracted configurations, respectively. Figure 1 The landing gear 10 is shown in the side view of Figure 5. Various components of the internal structure of the wing 4, including the ribs 44, the front spar 46, and the rear spar 48, are... Figure 6a The middle part is represented by a dashed line.

[0060] In the deployed configuration, the main strut 16 is generally vertical and located outside the fuselage 2 and behind the wing 4 (see [reference]). Figure 5(a) and 6(a) ).

[0061] In the retracted configuration, wheel 18 is almost entirely positioned within landing gear bay 14, and main strut 16 is angled and slightly higher than horizontal (see...). Figure 5(b) and 6(b) When viewed in the plan view (see Figure 5), it is clear that when the landing gear 10 has been retracted, the lower end of the main strut 16 has rotated forward and inward.

[0062] As described above, the landing gear axis 50 is not parallel to either the longitudinal or lateral axis of the aircraft 1. Therefore, in the landing gear according to this embodiment, the main strut 16 (and the wheels 18 mounted on the main strut 16) can move forward and inward, thereby allowing the landing gear components (in this case, the wheels 18) to be stored in the landing gear bay 14, which is formed in the fuselage 2 behind the wing 4, when the aircraft is in flight. Therefore, the landing gear according to this embodiment facilitates integration of the landing gear into the aircraft. In some embodiments, the landing gear axis can be substantially parallel to either the longitudinal or lateral axis of the aircraft. For example, in some configurations, a landing gear axis substantially parallel to the longitudinal axis of the aircraft allows the main strut to rotate inward, such that the landing gear wheels and / or other components are received in the landing gear bay formed in the fuselage.

[0063] It should be understood that although the landing gear 10 and main assembly 28 are shown as exposed in the above figures, in use, one or more drag-reducing fairings will cover some or all of these components.

[0064] Although the invention has been described and illustrated with reference to specific embodiments, it will be understood by those skilled in the art that the invention leads itself to many different variations not specifically described herein.

[0065] Where references have been made in the foregoing description to any known, obvious, or foreseeable equivalents of any element or component, such equivalents are incorporated herein as if separately stated. The true scope of the invention should be determined with reference to the claims, and should be interpreted as including any of these equivalents. It should also be understood that elements or features of the invention described as preferred, advantageous, convenient, etc., are optional and not intended to limit the scope of the independent claims. Furthermore, it should be understood that in some embodiments of the invention, such optional elements or features, while potentially beneficial, may not be desirable and therefore may not be present in other embodiments.

Claims

1. An aircraft comprising a fuselage and a retractable landing gear assembly mounted on the fuselage, the landing gear assembly comprising: - a main strut; - a drag strut, a first end of the drag strut being attached to the main strut and a second end of the drag strut being connected to the fuselage such that landing gear loads can be transmitted from the drag strut into the fuselage of the aircraft; - a landing gear main fitting, a first end of the landing gear main fitting being attached to the main strut and a second end of the landing gear main fitting being connected to the fuselage by a fuselage main fitting assembly such that landing gear loads can be transmitted from the landing gear main fitting into the fuselage of the aircraft; wherein the fuselage main fitting assembly comprises a main beam pivotally connected to the landing gear main fitting about a landing gear axis that is inclined relative to both a longitudinal axis and a lateral axis of the aircraft and attached to the fuselage, and a plurality of support members connected at one end to the main beam and attached at the other end to the fuselage; and wherein, in use, when the landing gear assembly is in a deployed configuration relative to the fuselage, all of the landing gear loads taken by the landing gear assembly are transmitted from the landing gear assembly to the fuselage only via one or more of the drag strut and the landing gear main fitting.

2. The aircraft of claim 1, the aircraft comprising a wing having an aft spar and the fuselage comprising a fuselage frame, and wherein, When the landing gear assembly is in the deployed configuration, the main strut is positioned rearward of the rear spar and / or outboard of the fuselage frame.

3. The aircraft of claim 1 or 2, the fuselage comprising a fuselage frame and a wheel assembly is mounted to a distal end of the main strut, and wherein, When the landing gear assembly is in a retracted configuration relative to the fuselage, at least a portion of the wheel assembly is received within a recess formed in the fuselage frame.

4. The aircraft of claim 1 or 2, the landing gear main fitting being pivotally connected to the fuselage for rotation about a landing gear axis such that the main strut can be rotated relative to the fuselage between a deployed position and a retracted position.

5. The aircraft of claim 4, wherein, The inclination of the landing gear axis causes a distal end of the main strut to move inward, forward and upward as the main strut moves from the deployed position toward the retracted position.

6. The aircraft of claim 4, wherein, The landing gear axis is inclined at an angle of 45 degrees relative to both the longitudinal axis and the lateral axis of the aircraft.

7. The aircraft of any of claims 1-2, 5, comprising a wing, and wherein, The second end of the drag strut is connected to the fuselage in a region where the wing joins the fuselage.

8. The aircraft of claim 7, the wing including an aft spar, and wherein, The drag strut is attached to the aircraft at a point positioned rearward of the rear spar.

9. The aircraft of claim 7, the wing comprising a plurality of ribs, and wherein, The drag strut is connected to the fuselage via one of the ribs positioned at a junction between the fuselage and the wing.

10. The aircraft of claim 9, the drag strut being connected to the fuselage via Rib 1 positioned at a junction between the fuselage and the wing.

11. The aircraft of claim 7, wherein, The drag strut extends forward from the main strut such that the second end of the drag strut is positioned forward of the first end of the drag strut.

12. The aircraft of any of claims 1-2, 5, 8-11, comprising a bulkhead, and wherein, The landing gear main fitting is connected to the fuselage via an aircraft main fitting attached to the bulkhead.

13. The aircraft of claim 12, the bulkhead being a rear pressure bulkhead.

14. A method of retracting a landing gear assembly mounted on a fuselage of an aircraft according to any one of claims 1-13, the method comprising the step of rotating the main strut about a landing gear axis to move the landing gear assembly relative to the fuselage from a deployed configuration to a retracted configuration.

15. The method of claim 14, wherein, The landing gear axis is inclined relative to a lateral axis and a longitudinal axis of the aircraft, and the step of rotating the main strut about the landing gear axis comprises moving the distal end of the main strut inwardly, forwardly and upwardly.

16. A landing gear assembly comprising: - a main strut having at least one pair of wheels mounted at a first end, each pair of wheels being arranged to rotate about a wheel axis; - a drag strut having a first end attached to the main strut and a second end for connection to a fuselage of an aircraft; - a landing gear main fitting for connecting the landing gear assembly to the fuselage of the aircraft through a fuselage main fitting assembly, the landing gear main fitting being attached to the main strut and defining a pivot axis about which the main strut is rotatable; wherein the fuselage main fitting assembly comprises a main beam pivotally connected to the landing gear main fitting about the pivot axis and attached to a fuselage, and a plurality of support members connected at one end to the main beam and attached at another end to a fuselage; - and wherein the pivot axis is neither perpendicular nor parallel to each of the wheel axes, and wherein, when the landing gear assembly is in a deployed configuration relative to the fuselage, all landing gear loads taken by the landing gear assembly are transmitted to the fuselage solely via one or more of the drag strut and the landing gear main fitting.

17. An aircraft comprising: - a fuselage having a frame, - two landing gear assemblies according to claim 16, each mounted on the fuselage, one on each side of the fuselage, and - two wings, each having an aft spar, and wherein, in use, when the landing gear assemblies are in a deployed configuration relative to the fuselage, the main strut is positioned outwardly of the frame and rearwardly of the aft spar of the wings.

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