High-wing aircraft with main landing gear bays spaced away from the fuselage
By offsetting the main landing gear bays from the fuselage and using structural links to distribute landing forces, the aircraft addresses the issue of fuselage deformation during emergency landings, improving structural integrity and performance.
Patent Information
- Application Number
- FR2024006933
- Authority / Receiving Office
- FR · FR
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-06-27
- Publication Date
- 2026-01-02
AI Technical Summary
In high-wing aircraft with main landing gear bays positioned adjacent to the fuselage, the fuselage section between the wing and the landing gear bays is subjected to high stress during emergency landings, leading to potential deformation or collapse due to the transfer of forces through the fuselage, which complicates door opening and may result in structural damage.
The main landing gear bays are offset from the fuselage in a transverse direction, with structural links connecting the landing gear bays to the wing and fuselage, forming alternative load paths that distribute the landing forces, reducing stress on the fuselage section and incorporating aerodynamic fairings to manage these loads.
This configuration significantly reduces the risk of fuselage deformation and preserves cabin volume by distributing landing forces through additional structural links, enhancing aircraft integrity and performance by minimizing deformation and eliminating the need for fairings, thus reducing drag.
Smart Images
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Abstract
Description
Title of the invention: High-wing aircraft comprising main landing gear bays spaced from the fuselage
[0001] The present application relates to a high-wing aircraft comprising main landing gear bays spaced away from the fuselage.
[0002] According to an embodiment visible in figures 1 to 3, an aircraft 10 comprises a fuselage 12, a wing 14 extending on either side of the fuselage 12, a tail assembly 16 positioned at the rear of the fuselage 12, main landing gear 18, 18' positioned in the lower part of the fuselage 12 and propulsion assemblies 20 positioned on either side of the fuselage 12, under the wing 14 and connected to the latter.
[0003] For each main landing gear 18, 18', the aircraft 10 includes a main landing gear box 18.1, 18.1' integrated into or adjacent to the fuselage 12. Each main landing gear 18, 18' is movable between a retracted position in which the main landing gear 18, 18' is positioned in the main landing gear box 18.1, 18.1', particularly when the aircraft 10 is in flight, and a deployed position in which the main landing gear 18, 18' is positioned at least partially outside the main landing gear box 18.1, 18.1', particularly when the aircraft 10 is on the ground.
[0004] According to one configuration, each main landing gear box 18.1, 18.1' is delimited by rigidified front and rear transverse panels.
[0005] As illustrated in [Fig. 2], the fuselage 12 comprises a fuselage structure, which includes transverse reinforcements 12.1 (called frames) positioned in planes perpendicular to a longitudinal direction and longitudinal reinforcements 12.2 (called stringers) oriented approximately parallel to the longitudinal direction, as well as a skin attached to the fuselage structure. In one configuration, the fuselage 12 includes a door 22 positioned under the wing 14.
[0006] According to one embodiment, the wing 14 comprises a wing structure including a front spar, a rear spar, and ribs, as well as a skin attached to the wing structure. In one arrangement, the wing 14 is positioned in the upper part of the fuselage 12, its rear spar being positioned substantially in the same transverse plane as the front panel of the main landing gear bays 18.1, 18.1'.
[0007] According to a configuration visible in figures 1 and 3, the aircraft 10 comprises four propulsion units 20, two on either side of the fuselage 12, which have a relatively large mass.
[0008] In the event of an emergency landing with the main landing gear 18, 18' in the retracted position, the forces from the wing 14 are transmitted through the fuselage section 12, particularly in a transverse plane located directly above the rear wing spar 14, to the lower part of the fuselage 12 in contact with the ground. Since the forward panels of the main landing gear bays 18.1, 18.1' are rigidified, the portion of the fuselage section 12 located between the wing 14 and the main landing gear bays 18.1, 18.1' is subjected to such high stress that it can deform and make it difficult to open the fuselage door 22 located under the wing 14, or even collapse, as illustrated in [Fig. 3], in the event of a violent ground impact.
[0009] The present invention aims to remedy all or part of the drawbacks of the prior art.
[0010] To this end, the invention relates to an aircraft comprising a fuselage which extends in a longitudinal direction, a wing, positioned in the upper part of the fuselage, which extends on either side of the fuselage in a transverse direction perpendicular to the longitudinal direction, right and left main landing gears, right and left main landing gear boxes, one for each right and left main landing gear, configured to house the right and left main landing gears in a retracted position, as well as propulsion assemblies positioned on either side of the fuselage and connected to the wing.
[0011] According to the invention, the right and left main landing gear bays are offset from the fuselage in the transverse direction. In addition, the aircraft comprises, for each right and left main landing gear bay, a first right or left structural link connecting the right or left main landing gear bay to the wing, and a second right or left structural link connecting the right or left main landing gear bay to the fuselage.
[0012] The first structural connections form two load paths between the wing and the ground, different from that formed by the fuselage. Thus, in the event of an emergency landing with the main landing gear retracted, the loads between the wing and the ground are not exclusively transferred by the fuselage but also by the first two structural connections positioned on either side of the fuselage and spaced away from it. As a result, the fuselage section located under the wing is subjected to less stress, which significantly reduces the risk of deformation and / or preserves the cabin volume.
[0013] According to another feature, each first right or left structural linkage has a first end attached to the wing and a second end attached to the right or left main landing gear bay, the first the ends of the first right and left structural links being more spaced out than the second ends of the first right and left structural links.
[0014] According to another feature, each first right or left structural linkage includes a first aerodynamic fairing which has an aerodynamic profile as well as leading and trailing edges positioned in a longitudinal plane forming a non-zero angle with a longitudinal vertical plane.
[0015] According to another feature, each first right or left structural linkage comprises a first structure linking a right or left main landing gear box structure and a wing structure, the first structure being positioned in the first aerodynamic fairing.
[0016] According to another feature, each first right or left structural link is configured to absorb compressive forces by its controlled, driven and / or programmed deformation.
[0017] According to another feature, each first right or left structural linkage includes a first end connected to the wing and positioned between the fuselage and the propulsion assembly closest to the fuselage, the first end being as close as possible to or at the level of the propulsion assembly.
[0018] According to another feature, each second right or left structural linkage has a first end attached to the fuselage and a second end attached to the right or left main landing gear box, the first ends of the second right and left structural links being closer to the wing than the second ends of the second right and left structural links.
[0019] According to another feature, each second right or left structural linkage includes a second aerodynamic fairing which has an aerodynamic profile as well as leading and trailing edges positioned in a longitudinal plane forming a non-zero angle with a horizontal plane.
[0020] According to another feature, each second right or left structural linkage comprises a second structure linking a right or left main landing gear box structure and a fuselage structure, the second structure being positioned in the second aerodynamic fairing.
[0021] According to another feature, the second right and left structural links are connected to a lower part of the fuselage.
[0022] According to another feature, each right or left main landing gear box is spaced from the fuselage by a distance such that the fuselage is located outside an ejection zone delimited by two vertical planes forming an angle a of the order 12° with the longitudinal direction and passing through the main landing gear housed in said right or left main landing gear box.
[0023] Other features and advantages will become apparent from the following description of the invention, given by way of example only, with reference to the accompanying drawings, among which:
[0024] [Fig-1] is a schematic front view of an aircraft illustrating a mode of realization of prior art,
[0025] [Fig.2] is a perspective view of a section of aircraft fuselage located under a wing illustrating an embodiment of the prior art,
[0026] [Fig.3] is a schematic front view of the aircraft visible in [Fig.1] in the event of an emergency landing with the main landing gear in the retracted position,
[0027] [Fig.4] is a front view of an aircraft illustrating an embodiment of the invention,
[0028] [Fig.5] is a perspective view of a part of the aircraft visible in [Fig.4],
[0029] [Fig.6] is a side view of a part of the aircraft visible in [Fig.4],
[0030] [Fig.7] is a schematic front view of an aircraft illustrating a mode of realization of the invention,
[0031] [Fig.8] is a schematic front view of the aircraft visible in [Fig.7] in the event of an emergency landing with the main landing gear retracted,
[0032] [Fig.9] is a bottom view of an aircraft illustrating an embodiment of the invention,
[0033] [Fig. 10] is a rear view of an aircraft illustrating another embodiment of the invention,
[0034] [Fig. 11] is a side view of the aircraft visible on [Fig. 10].
[0035] According to an embodiment visible in Figures 4 to 6 and 9, an aircraft 30 comprises a fuselage 32 which extends along a longitudinal direction X (visible in [Fig.9]) between front and rear tips 32.1, 32.2, a wing 34 which extends along a transverse direction Y (perpendicular to the longitudinal direction X) on either side of the fuselage 32, an empennage 36 positioned at the rear tip 32.2 of the fuselage 32, main landing gear 38, 38' and propulsion assemblies 40.1, 40.2, 40.1', 40.2' positioned on either side of the fuselage 32, under the wing 34 and connected to the latter. According to an embodiment visible in [Fig. 1 1], the wing 34 comprises a rigid wing structure 34.1 which extends, in a transverse direction, on either side of the fuselage 32. According to one configuration, the wing structure 34.1 is positioned in the upper part of the fuselage 32.
[0036] For each main landing gear 38, 38', the aircraft 30 comprises a main landing gear bay 38.1, 38.1', each main landing gear 38, 38' being movable between a retracted position, visible in dashed lines in [Fig. 6], in which the main landing gear 38, 38' is positioned in the main landing gear bay 38.1, 38.1', particularly when the aircraft 30 is in flight, thus that a deployed position, clearly visible in [Fig. 6], in which the main landing gear 38, 38' is positioned at least partially outside the main landing gear bay 38.1, 38.1', particularly when the aircraft 30 is on the ground. Thus, the aircraft 30 comprises right and left main landing gear bays 38.1, 38.1' that are substantially symmetrical with respect to a vertical median plane PMV.
[0037] In one configuration, the fuselage 32 comprises a fuselage structure that includes transverse reinforcements (called frames) positioned in planes perpendicular to the longitudinal direction X and longitudinal reinforcements (called stringers) oriented approximately parallel to the longitudinal direction X, as well as a skin attached to the fuselage structure. The fuselage 32 includes a fuselage section positioned under the wing 34.
[0038] According to one embodiment, the wing 34 is positioned in the upper part of the fuselage 32. According to one configuration, the wing 34 comprises a wing structure which includes a front spar, a rear spar and ribs as well as a skin attached to the wing structure.
[0039] According to a configuration visible in Figures 4, 5, 7 to 9 and 3, the aircraft 30 comprises four propulsion units 40.1, 40.2, 40.1', 40.2', two on either side of the fuselage 32, a first propulsion unit 40.1, 40.1' close to the fuselage 32 and a second propulsion unit 40.2, 40.2' further away from the fuselage 32 than the first propulsion unit 40.1, 40.1'. Of course, the invention is not limited to this number of propulsion units.
[0040] By way of example, each propulsion unit is a turboprop. Each of them has a relatively large mass.
[0041] The fuselage 32, the wing 34, the tail assembly 36 and the propulsion assemblies 40.1, 40.2, 40.1', 40.2' are not further described as they may be identical to those of the prior art.
[0042] According to a particular feature of the invention, the main landing gear boxes 38.1, 38.1' are positioned on either side of the fuselage 32, each of them being separated from the fuselage 32 along the transverse direction Y.
[0043] According to one design, each main landing gear box 38.1, 38.1' comprises a landing gear box structure configured to house the main landing gear 38, 38' in the retracted position, at least one hinge configured to connect the main landing gear box structure and the main landing gear 38, 38', at least one actuator configured to move the main landing gear 38, 38' and an aerodynamic fairing 42 surrounding the landing gear box structure.
[0044] The aircraft 30 comprises, for each main landing gear bay 38.1, 38.1', a first structural link 44 connecting the landing gear bay main 38.1, 38.1' and wing 34 as well as a second structural link 46 connecting the main landing gear box 38.1, 38.1' and the fuselage 32.
[0045] Thus, the aircraft 30 comprises right and left pairs of first and second structural links 44, 46 substantially symmetrical with respect to the vertical median plane PMV.
[0046] Each first structural linkage 44 includes a first structure connecting the main landing gear box structure 38.1, 38.1' and the wing structure 34 and a first aerodynamic fairing 48. The latter has an aerodynamic profile comprising a leading edge 48.1 and a trailing edge 48.2 (visible on [Fig.6]).
[0047] According to one configuration, the leading and trailing edges 48.1, 48.2 are positioned in a longitudinal plane (containing the longitudinal direction X) which forms a non-zero angle, generally less than 20°, with a longitudinal vertical plane.
[0048] The first structural link 44 has a first end 44.1 attached to the wing 34 and a second end 44.2 attached to the main landing gear box 38.1, 38.1'. The first end 44.1 is positioned between the fuselage 32 and the first propulsion unit 40.1, 40.1', as close as possible to or at the level of the first propulsion unit 40.1, 40.1'.
[0049] According to one configuration, the first ends 44.1 of the first right and left structural links 44 are spaced a greater distance apart than that separating the second ends 44.2 of the first right and left structural links 44.
[0050] Regardless of the arrangement, the first structural links 44 form two load paths between the wing 34 and the ground, different from that formed by the fuselage 32. Thus, in the event of an emergency landing with the main landing gear retracted or not, the forces between the wing 34 and the ground are not transferred solely by the fuselage 32, as in the prior art, but also by the first two structural links 44 positioned on either side of the fuselage 32 and spaced apart from it. As illustrated in [Fig. 8], the fuselage section 32 located under the wing 34 is subjected to less stress, which significantly reduces the risk of deformation or crushing of this section.
[0051] According to another advantage, the fairings for the main landing gear bays 38.1, 38.1' are no longer necessary. They can therefore be removed, which improves aircraft performance by reducing the wetted surface area and thus drag.
[0052] As illustrated in [Fig.8], after an impact, the main landing gear boxes 38.1, 38.1' and the second structural links 46 right and left can form ski-like sliding surfaces.
[0053] According to one embodiment, each first structural link 44 is configured to absorb compressive forces by its controlled, driven and / or programmed deformation.
[0054] Each second structural linkage 46 includes a second structure connecting the main landing gear box structure 38.1, 38.1' and the fuselage structure of the fuselage 32 and a second aerodynamic fairing 50. The latter has an aerodynamic profile comprising a leading edge 50.1 and a trailing edge 50.2 (visible in [Fig.5]).
[0055] According to one configuration, the leading and trailing edges 50.1, 50.2 are positioned in a longitudinal plane which forms a non-zero angle with a horizontal plane, generally less than 20°.
[0056] The second structural link 46 has a first end 46.1 attached to the fuselage 32 and a second end 46.2 attached to the main landing gear box 38.1, 38.1'.
[0057] According to one configuration, the first ends 46.1 of the second right and left structural links 46 are closer to the wing 34 than the second ends 46.2 of the second right and left structural links 46.
[0058] The second right and left structural links 46 are connected to a lower part of the fuselage 32.
[0059] According to an embodiment visible in Figures 10 and 11, the fuselage 32 comprises a transverse structure 32.3 positioned in the lower part of the fuselage 32, directly above the wing structure 34.1, connecting the first ends 46.1 of the second right and left structural links 46. The fuselage 32 may include a longitudinal beam 32.4, positioned under the transverse structure 32.3, connecting two fuselage sections positioned on either side of the transverse structure 32.3.
[0060] As illustrated in [Fig. 9], each main landing gear bay 38.1, 38.1' is spaced from the fuselage 32 at a distance such that the fuselage 32 is located outside an ejection zone 52 delimited by two vertical planes 52.1, 52.2 forming an angle α between 5 and 30°, on the order of 12° with the longitudinal direction X and passing through the main landing gear 38, 38' housed in said main landing gear bay 38.1, 38.1'. Thus, in the event of ejection of a part of the main landing gear 38, 38', the latter does not impact the fuselage or any fuel tank positioned in the fuselage 32.
[0061] According to one embodiment, at least one of the first and second structural links 44, 46 includes at least one housing configured to possibly house aircraft equipment.
Claims
Demands
1. Aircraft comprising a fuselage (32) extending along a longitudinal direction (X), a wing (34), positioned on the upper part of the fuselage (32), extending on either side of the fuselage (32) along a transverse direction (Y) perpendicular to the longitudinal direction (X), right and left main landing gear (38, 38'), right and left main landing gear bays (38.1, 38.1'), one for each right and left main landing gear (38, 38'), configured to house the right and left main landing gear (38, 38') in a retracted position, and propulsion assemblies (40.1, 40.2, 40.1', 40.2') positioned on either side of the fuselage (32) and connected to the wing (34); characterized in that the main landing gear boxes right and left (38.1, 38.1') are separated from the fuselage (32) in the transverse direction (Y) and in that the aircraft comprises, for each right and left main landing gear box (38.1, 38.1'), a first right or left structural linkage (44) connecting the right or left main landing gear box (38.1, 38.1') and the wing (34) and a second right or left structural linkage (46) connecting the right or left main landing gear box (38.1, 38.1') and the fuselage (32).
2. Aircraft according to claim 1, characterized in that each first right or left structural linkage (44) has a first end (44.1) integral with the wing (34) and a second end (44.2) integral with the right or left main landing gear box (38.1, 38.1'), the first ends (44.1) of the first right and left structural links (44) being more spaced apart than the second ends (44.2) of the first right and left structural links (44).
3. Aircraft according to any one of the preceding claims, characterized in that each first right or left structural linkage (44) comprises a first aerodynamic fairing (48) which has an aerodynamic profile as well as leading and trailing edges (48.1, 48.2) positioned in a longitudinal plane forming a non-zero angle with a longitudinal vertical plane.
4. Aircraft according to the preceding claim, characterized in that each first right or left structural linkage (44) comprises a first structure linking a right or left main landing gear box structure (38.1, 38.1') and a wing structure (34), the first structure being positioned in the first aerodynamic fairing (48).
5. Aircraft according to any one of the preceding claims, characterized in that each first right or left structural linkage (44) is configured to absorb compressive forces by its controlled, piloted and / or programmed deformation.
6. Aircraft according to any one of the preceding claims, characterized in that each first right or left structural linkage (44) comprises a first end (44.1) connected to the wing (34) and positioned between the fuselage (32) and the propulsion assembly (40.1, 40.1') closest to the fuselage (32), the first end (44.1) being as close as possible to, or at, the propulsion assembly (40.1, 40.1').
7. Aircraft according to any one of the preceding claims, characterized in that each second right or left structural link (46) has a first end (46.1) integral with the fuselage (32) and a second end (46.2) integral with the right or left main landing gear box (38.1, 38.1'), the first ends (46.1) of the second right and left structural links (46) being closer to the wing (34) than the second ends (46.2) of the second right and left structural links (46).
8. Aircraft according to any one of the preceding claims, characterized in that each second right or left structural linkage (46) comprises a second aerodynamic fairing (50) which has an aerodynamic profile as well as leading and trailing edges (50.1, 50.2) positioned in a longitudinal plane forming a non-zero angle with a horizontal plane.
9. Aircraft according to the preceding claim, characterized in that each second right or left structural linkage (46) comprises a second structure linking a right or left main landing gear box structure (38.1, 38.1') and a fuselage structure (32), the second structure being positioned in the second aerodynamic fairing (50).
10. Aircraft according to any one of the preceding claims, characterized in that the second right and left structural links (46) are connected to a lower part of the fuselage (32) close to the vertical median plane (VMP).
11. Aircraft according to any one of the preceding claims, characterized in that each right or left main landing gear box (38.1, 38.1') is spaced from the fuselage (32) by a distance such that the fuselage (32) is located outside an ejection zone (52) delimited by two vertical planes (52.1, 52.2) forming an angle α of the order 12° with the longitudinal direction (X) and passing through the right or left main landing gear (38, 38') housed in said right or left main landing gear box (38.1, 38.1').
Citation Information
Patent Citations
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