Aircraft subassembly having a main landing gear assembly and a protrusion

Abstract

The present disclosure relates to an aircraft subassembly having a main landing gear assembly and a protrusion. The aircraft subassembly (100) includes a fuselage structure (102). The aircraft subassembly (100) further includes a main landing gear system (104). The main landing gear system (104) further includes a protrusion (130) connected to the fuselage structure (102) and extending outward from the fuselage structure (102). The protrusion (130) includes: a central portion (131); a first main landing gear door (140) that is movable relative to the central portion (131) between a closed position and an open position, including the closed position and the open position; and a second main landing gear door (142) that is movable relative to the central portion (131) between a closed position and an open position, including the closed position and the open position. The main landing gear system (104) further includes a first main landing gear assembly (106) connected to the first wheel (110) and a second main landing gear assembly (112) connected to the second wheel (116).

Description

Technical Field

[0001] The present disclosure relates to an aircraft subassembly having a main landing gear assembly and a nose that receives the main landing gear assembly. Background Art

[0002] At least some known aircraft are designed with a passenger cabin located above the cargo hold. Many such aircraft have a low-wing configuration, with the main landing gear primarily located in the fuselage bay below the passenger cabin. However, in cargo aircraft, it is desirable to maximize the amount of available cargo space. Therefore, the passenger cabin is eliminated, and the cargo floor is positioned as close to the ground as possible. As a result, the space available within the fuselage for integrating the main landing gear is highly limited. Summary of the Invention

[0003] Therefore, an apparatus and method directed to addressing at least the above-mentioned problems would be of practical use.

[0004] The following is a non-exclusive list of examples disclosed herein.

[0005] Disclosed herein is an aircraft subassembly comprising a fuselage structure. The fuselage structure has a first side comprising a plurality of first frame members. The fuselage structure also has a second side comprising a plurality of second frame members. The aircraft subassembly further comprises a wing attached to the fuselage structure. The aircraft subassembly comprises a main landing gear system comprising a pair of wheels. The pair of wheels comprises a first wheel having a first wheel azimuth rotational symmetry axis and a first wheel mid-plane perpendicular to the first wheel azimuth rotational symmetry axis, and a second wheel having a second wheel azimuth rotational symmetry axis and a second wheel mid-plane perpendicular to the second wheel azimuth rotational symmetry axis. The main landing gear system further comprises a protrusion connected to and extending outward from the fuselage structure. The protrusion comprises a central portion and a first main landing gear door movable relative to the central portion between a closed position and an open position, inclusive. The protrusion further comprises a second main landing gear door movable relative to the central portion between a closed position and an open position, inclusive. The main landing gear system also includes a first main landing gear assembly connected to the first wheel and a second main landing gear assembly connected to the second wheel.

[0006] In an exemplary configuration, the main landing gear system includes only two wheels, which reduces the weight of the aircraft subassembly while still accommodating a comparable takeoff weight compared to other similarly sized cargo aircraft. In other words, the main landing gear system allows the aircraft subassembly to carry a similar amount of cargo weight as other, larger aircraft that include larger landing gear assemblies. Thus, the aircraft subassembly described herein reduces operating costs because less fuel is required to transport a comparable amount of cargo. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Reference will now be made to the accompanying drawings, which are not necessarily drawn to scale and in which like reference numerals designate the same or similar parts throughout the several views. In the drawings:

[0008] Figure 1A 、 Figure 1B and Figure 1C collectively, a block diagram of an aircraft subassembly according to one or more examples of the subject matter disclosed herein;

[0009] Figure 2 is disclosed herein according to one or more examples of the subject matter Figure 1A 、 Figure 1B and Figure 1C a schematic elevation view of an aircraft subassembly;

[0010] Figure 3 is disclosed herein according to one or more examples of the subject matter Figure 1A 、 Figure 1B and Figure 1C a schematic partial cross-sectional view of an aircraft subassembly illustrating the fuselage structure and a pair of main landing gear assemblies in an extended position;

[0011] Figure 4 is disclosed herein according to one or more examples of the subject matter Figure 1A 、 Figure 1B and Figure 1C a schematic partial cross-sectional view of an aircraft subassembly illustrating a pair of main landing gear assemblies in a retracted position within a nose;

[0012] Figure 5 is disclosed herein according to one or more examples of the subject matter Figure 4 A schematic bottom view of the protrusion;

[0013] Figure 6 is disclosed herein according to one or more examples of the subject matter Figure 4 A schematic perspective view of a protrusion;

[0014] Figure 7 is disclosed herein according to one or more examples of the subject matter Figure 1A 、 Figure 1B and Figure 1C A schematic cross-sectional view of an aircraft subassembly;

[0015] Figure 8A 、 Figure 8B and Figure 8C is a device according to one or more examples of the subject matter disclosed herein in an extended configuration, an extended / compressed configuration, and a retracted configuration Figure 3 a schematic perspective view of a main landing gear assembly;

[0016] Figure 9A and Figure 9B is disclosed herein according to one or more examples of the subject matter Figure 5 a schematic perspective view of a protrusion of , illustrating the main landing gear assembly in a retracted position and in an extended position;

[0017] Figure 10A and Figure 10B is disclosed herein according to one or more examples of the subject matter Figure 5 a schematic bottom view of a protrusion of , illustrating the main landing gear assembly in a retracted position and in an extended position;

[0018] Figure 11A and Figure 11B is disclosed herein according to one or more examples of the subject matter Figure 5 a schematic side elevational view of a protrusion illustrating the main landing gear assembly in a retracted position and in an extended position;

[0019] Figure 12A and Figure 12B is disclosed herein according to one or more examples of the subject matter Figure 5 a schematic front elevational view of a nose portion illustrating the main landing gear assembly in a retracted position and in an extended position;

[0020] Figure 13 is a schematic perspective view of a main landing gear assembly in a retracted position and in an extended position according to one or more examples of the subject matter disclosed herein;

[0021] Figure 14 is a schematic perspective view of a main landing gear assembly, fuselage structure, and protrusion according to one or more examples of the subject matter disclosed herein;

[0022] Figure 15 is a schematic perspective view of a main landing gear assembly and fuselage structure according to one or more examples of the subject matter disclosed herein;

[0023] Figure 16 is a block diagram of how aircraft are built and maintained; and

[0024] Figure 17 is a schematic illustration of an aircraft. DETAILED DESCRIPTION

[0025] In the above mentioned Figure 1A 、 Figure 1B and Figure 1CIn the block diagram, the solid lines (if any) connecting various elements and / or components can represent mechanical, electrical, fluid, optical, electromagnetic and other connectors and / or their combinations. As used herein, "connected" means directly and indirectly associated. For example, component A can be directly associated with component B, or component A can be indirectly associated with component B, for example, by means of other components C. It should be understood that it is not necessary to express all the relationships between the various elements disclosed. Therefore, there may also be connections other than those depicted in the block diagram. The dotted lines (if any) connecting the boxes representing various elements and / or components represent connections that are similar in function and purpose to those represented by the solid lines; however, the connections represented by the dotted lines may be selectively provided or may be related to alternative examples of the themes disclosed herein. Similarly, the elements and / or components (if any) represented by dotted lines indicate alternative examples of the themes disclosed herein. Without departing from the scope of the themes disclosed herein, one or more elements shown by solid and / or dotted lines may be omitted in a specific example. Environmental elements (if any) are represented by dotted lines. For clarity, virtual (imaginary) elements may also be shown. Those skilled in the art will understand that Figure 1A 、 Figure 1B and Figure 1C Some of the features exemplified in the may be combined in various ways and need not include Figure 1A 、 Figure 1B and Figure 1C , other features described in the accompanying drawings and / or the accompanying disclosure, even if this combination or these combinations are not explicitly illustrated herein. Similarly, additional features not limited to the examples presented may be combined with some or all of the features shown and described herein.

[0026] In the above mentioned Figure 16 and Figure 17 In the present disclosure, blocks may represent operations and / or portions thereof, and lines connecting various blocks do not imply any particular order or dependency of the operations or portions thereof. Blocks represented by dashed lines indicate alternative operations and / or portions thereof. Dashed lines connecting various blocks, if any, indicate alternative dependencies of the operations or portions thereof. It will be understood that not all dependencies between the various disclosed operations are necessarily represented. Figure 16 and Figure 17 The attached disclosure describing the operation of the method set forth herein should not be construed as necessarily determining the sequence in which the operations will be performed. Specifically, although an illustrative order is indicated, it is understood that the order of the operations may be modified when appropriate. Therefore, certain operations may be performed in different orders or simultaneously. In addition, it will be appreciated by those skilled in the art that not all operations described need to be performed.

[0027] In the following description, numerous specific details are set forth to provide a thorough understanding of the disclosed concepts, but these concepts can be practiced without some or all of these details. In other instances, details of well-known devices and / or processes have been omitted to avoid unnecessarily obscuring the present disclosure. Although some concepts will be described in conjunction with specific examples, it should be understood that these examples are not intended to be limiting.

[0028] Unless otherwise indicated, the terms "first," "second," etc., are used herein merely as labels and are not intended to impose order, position, or hierarchy requirements on the items to which these terms refer. Furthermore, reference to an item, for example, "second," does not require or preclude the presence of, for example, a "first" or lower-numbered item and / or, for example, a "third" or higher-numbered item.

[0029] Reference to "one or more examples" herein means that one or more features, structures, or characteristics described in conjunction with the example are included in at least one implementation. The phrase "one or more examples" in various places in the specification may or may not refer to the same example.

[0030] As used herein, a system, device, structure, article, element, component, or hardware that is “configured to” perform a specified function is indeed capable of performing the specified function without any changes, rather than merely being likely to perform the specified function after further modification. In other words, a system, device, structure, article, element, component, or hardware that is “configured to” perform a specified function is specifically selected, created, implemented, utilized, programmed, and / or designed for the purpose of performing the specified function. As used herein, “configured to” refers to existing characteristics of a system, device, structure, article, element, component, or hardware that enable the system, device, structure, article, element, component, or hardware to perform the specified function without further modification. For purposes of this disclosure, additionally or alternatively, a system, device, structure, article, element, component, or hardware that is described as “configured to” perform a particular function may be described as “adapted to” and / or “operable to” perform that function.

[0031] The following provides illustrative, non-exclusive examples of the subject matter disclosed herein that may or may not be claimed.

[0032] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figures 3 to 15, discloses an aircraft subassembly 100. Aircraft subassembly 100 includes a fuselage structure 102, fuselage structure 102 including a first side 108, first side 108 including a first plurality of frame members 109. Fuselage structure 102 also includes a second side 114, second side 114 including a second plurality of frame members 115. Aircraft subassembly 100 also includes an aileron 103 attached to fuselage structure 102. Additionally, aircraft subassembly 100 includes a main landing gear system 104 having a pair of wheels 107. Wheel pair 107 is comprised of a first wheel 110 having a first wheel azimuth rotational symmetry axis 111 and a first wheel midplane 113 perpendicular to first wheel azimuth rotational symmetry axis 111, and a second wheel 116 having a second wheel azimuth rotational symmetry axis 117 and a second wheel midplane 119 perpendicular to second wheel azimuth rotational symmetry axis 117. Additionally, main landing gear system 104 includes a protrusion 130 coupled to and extending outwardly from fuselage structure 102. Protrusion 130 includes a center portion 131 and a first main landing gear door 140 movable relative to center portion 131 between a closed position and an open position, inclusive. Protrusion 130 includes a second main landing gear door 142 movable relative to center portion 131 between a closed position and an open position, inclusive. Main landing gear system 104 also includes a first main landing gear assembly 106 coupled to first wheel 110 and a second main landing gear assembly 112 coupled to second wheel 116. The foregoing description of this paragraph represents a first example of the subject matter disclosed herein.

[0033] In the exemplary configuration, the main landing gear system 104 includes only two wheels, which reduces the weight of the aircraft subassembly 100 while still accommodating a comparable takeoff weight compared to other similarly sized cargo aircraft. In other words, the main landing gear system 104 allows the aircraft subassembly 100 to carry a similar amount of cargo weight as other larger aircraft that include larger landing gear assemblies. Thus, the aircraft subassembly 100 described herein reduces operating costs because less fuel is required to transport a comparable amount of cargo.

[0034] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 、 Figure 8B and Figure 10BAircraft subassembly 100 further includes a virtual symmetry plane 120 equidistant from first side 108 of fuselage structure 102 and second side 114 of fuselage structure 102. A central portion 131 of protrusion 130 includes a first circumferential opening cutout 149 and a second circumferential opening cutout 151. Virtual symmetry plane 120 passes between first circumferential opening cutout 149 and second circumferential opening cutout 151. The foregoing of this paragraph characterizes a second example of the subject matter disclosed herein, wherein the second example also encompasses the first example above.

[0035] Positioning the first circumferential opening cut 149 and the second circumferential opening cut 151 on opposite sides and equidistant from the imaginary symmetry plane 120 balances the aircraft subassembly 100 and allows for easier and less expensive manufacturing due to the symmetrical configuration.

[0036] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 8B and Figure 10B , the first circumferential opening cutout 149 is non-circular.The foregoing of this paragraph characterizes a third example of the subject matter disclosed herein, wherein the third example also encompasses the second example above.

[0037] The first circumferential opening cut 149 is non-circular to account for the shape of the first main landing gear door 140 .

[0038] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 and Figure 6 , fuselage structure 102 has a fuselage outer surface 136 having a fuselage surface area SA1, and projection 130 has a projection outer surface 138 having a projection surface area SA2. Projection surface area SA2 is 10% to 15% of fuselage surface area SA1. The foregoing of this paragraph characterizes a fourth example of the subject matter disclosed herein, where the fourth example also encompasses the third example above.

[0039] A relatively low ratio of protrusion surface area SA2 to fuselage surface area SA1 is associated with a relatively small size of protrusion 130. In this configuration, protrusion 130 exhibits a low drag coefficient on aircraft subassembly 100 when an aircraft based on aircraft subassembly 100 is airborne. As used herein, the term "drag coefficient" is defined as a dimensionless quantity used to quantify the wind resistance or drag force of an object in a fluid environment, such as air. Reducing the drag coefficient of protrusion 130 based on aircraft subassembly 100 can improve the performance of aircraft subassembly 100 as it relates to the speed and fuel efficiency of the aircraft. Specifically, a low drag coefficient enables an aircraft associated with aircraft subassembly 100 to have an increased maximum speed and improved fuel efficiency.

[0040] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 and Figure 6 , the protrusion surface area SA2 is 11% to 13% of the fuselage surface area SA1.The foregoing of this paragraph characterizes a fifth example of the subject matter disclosed herein, wherein the fifth example also encompasses the fourth example above.

[0041] As described herein, a smaller ratio of the protrusion surface area SA2 to the fuselage surface area SA1 is associated with a relatively low drag coefficient for the protrusion 130. Reducing the drag coefficient of the protrusion 130 improves the performance of the aircraft subassembly 100 as it relates to the speed and fuel efficiency of the associated aircraft. Specifically, a low drag coefficient enables an increase in the maximum speed and increased fuel efficiency of an aircraft based on the aircraft subassembly 100.

[0042] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 and Figure 6 , the protrusion surface area SA2 is 12% of the fuselage surface area SA1.The foregoing of this paragraph characterizes a sixth example of the subject matter disclosed herein, wherein the sixth example also encompasses the fifth example above.

[0043] As described herein, a smaller ratio of the protrusion surface area SA2 to the fuselage surface area SA1 is associated with a relatively low drag coefficient for the protrusion 130. Reducing the drag coefficient of the protrusion 130 improves the performance of the aircraft subassembly 100 as it relates to the speed and fuel efficiency of the associated aircraft. Specifically, a low drag coefficient enables an increase in the maximum speed and increased fuel efficiency of an aircraft based on the aircraft subassembly 100.

[0044] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 and Figure 6 , first main landing gear door 140 has a first main landing gear door surface area SA3, and second main landing gear door 142 has a second main landing gear door surface area SA4. First main landing gear door surface area SA3 and second main landing gear door surface area SA4 form a portion of protrusion surface area SA2. The foregoing content of this paragraph represents a seventh example of the subject matter disclosed herein, wherein the seventh example also encompasses any of the fourth to sixth examples above.

[0045] The outer surfaces of first and second main landing gear doors 140, 142 are flush with the outer surface of central portion 131 of protrusion 130 and are also exposed to the external environment when the aircraft based on aircraft subassembly 100 is in flight. Thus, based on aircraft subassembly 100, first and second main landing gear doors 140, 142 form part of protrusion 130 to reduce the drag coefficient of protrusion 130 and increase the fuel efficiency of the aircraft.

[0046] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figures 3 to 5When the first main landing gear door 140 and the central portion 131 of the protrusion 130 are in the closed position, they together form a first circumferentially closed opening 152. The first circumferentially closed opening 152 has a first axis of rotational symmetry 153 perpendicular to a virtual plane, and the projection of the first circumferentially closed opening 152 into the virtual plane has its maximum area. When the second main landing gear door 142 and the central portion 131 of the protrusion 130 are in the closed position, they together form a second circumferentially closed opening 154. The second circumferentially closed opening 154 is circumferentially closed and has a second axis of rotational symmetry 155 perpendicular to the virtual plane, and the projection of the second circumferentially closed opening 154 into the virtual plane has its maximum area. The first main landing gear assembly 106 is connected to at least one of the plurality of first frame members 109. The first main landing gear assembly 106 is also pivotable relative to the at least one of the plurality of first frame members 109 and is selectively movable between a retracted position and an extended position (inclusive). When first main landing gear assembly 106 is in the retracted position, first main landing gear door 140 is in the closed position, and first wheel azimuth rotational symmetry axis 111 is collinear with first opening rotational symmetry axis 153. When first main landing gear assembly 106 is in the extended position, first main landing gear door 140 is in the open position, and first wheel azimuth rotational symmetry axis 111 is non-collinear with first opening rotational symmetry axis 153. Second main landing gear assembly 112 is connected to at least one of the plurality of second frame members 115. Second main landing gear assembly 112 is also pivotable relative to at least one of the plurality of second frame members 115 and is selectively movable between a retracted position and an extended position, inclusive. When second main landing gear assembly 112 is in the retracted position, second main landing gear door 142 is in the closed position, and second wheel azimuth rotational symmetry axis 117 is collinear with second opening rotational symmetry axis 155. When second main landing gear assembly 112 is in the extended position, second main landing gear door 142 is in the open position, and second wheel azimuth rotational symmetry axis 117 is non-collinear with second opening rotational symmetry axis 155. The foregoing content of this paragraph characterizes an eighth example of the subject matter disclosed herein, wherein the eighth example also encompasses any of the fourth to seventh examples above.

[0047] In the exemplary configuration, the main landing gear system 104 includes only two wheels, which reduces the weight of the aircraft subassembly 100 while still accommodating a comparable takeoff weight compared to other similarly sized cargo aircraft. In other words, the main landing gear system 104 allows an aircraft based on the aircraft subassembly 100 to carry a similar amount of cargo weight as other, larger aircraft that include larger landing gear assemblies. Thus, the aircraft based on the aircraft subassembly 100 described herein can have lower operating costs because less fuel is required to transport a comparable amount of cargo.

[0048] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 , the protrusion surface area SA2 does not include the areas of the first circumferential closed opening 152 and the second circumferential closed opening 154. The foregoing of this paragraph characterizes a ninth example of the subject matter disclosed herein, wherein the ninth example also encompasses the eighth example above.

[0049] As used herein, the term "circumferentially closed" is used to describe any closed, rounded shape, such as, but not limited to, a circle, an oval, an ellipse, and the like. By forming the first circumferentially closed opening 152 and the second circumferentially closed opening 154 in the protrusion 130, less structural material is required to manufacture the protrusion 130 than when the first and second main landing gear doors 140, 142 are extended to cover the first and second circumferentially closed openings 152, 154, respectively. This reduced material simplifies the manufacture of the aircraft subassembly 100 and also reduces its overall weight.

[0050] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 、 Figure 8B and Figure 10B , first circumferential open cutout 149 further includes curvilinear boundary edge 144. At least a portion of curvilinear boundary edge 144 forms only a portion of first circumferential closed opening 152. The foregoing of this paragraph characterizes a tenth example of the subject matter disclosed herein, wherein the tenth example also encompasses the ninth example above.

[0051] The curvilinear boundary edge 144 forms a portion of both the first circumferential open cut 149 and the first circumferential closed opening 152 such that at least a portion of the first circumferential open cut 149 overlaps a portion of the first circumferential closed opening 152 .

[0052] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 、 Figure 8B and Figure 10B , the first circumferential opening cut 149 further includes a first boundary edge 162 extending from the curvilinear boundary edge 144. The foregoing of this paragraph characterizes an eleventh example of the subject matter disclosed herein, wherein the eleventh example also encompasses the tenth example above.

[0053] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 、 Figure 8B and Figure 10B , the first circumferential opening cut 149 also includes a second boundary edge 164 extending from the curvilinear boundary edge 144. The foregoing of this paragraph characterizes a twelfth example of the subject matter disclosed herein, wherein the twelfth example also encompasses the eleventh example above.

[0054] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 、 Figure 8B and Figure 10B , curvilinear boundary edge 144 has a curvilinear boundary edge first end 166 and a curvilinear boundary edge second end 168 spaced apart from curvilinear boundary edge first end 166. First boundary edge 162 extends from curvilinear boundary edge first end 166. The foregoing of this paragraph characterizes a thirteenth example of the subject matter disclosed herein, wherein the thirteenth example also encompasses the twelfth example above.

[0055] First boundary edge 162, extending from curved boundary edge first end 166, forms a vertex at which first boundary edge 162 and curved boundary edge first end 166 intersect. Specifically, first boundary edge 162 and curved boundary edge first end 166 form a convex vertex or corner that avoids stress risers, which are inherently formed in inner or concave vertices or corners. Fewer or no stress risers reduce fatigue of protrusion 130 and can extend the service life of protrusion 130.

[0056] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 、 Figure 8B and Figure 10B , second boundary edge 164 extends from curvilinear boundary edge second end 168. The foregoing of this paragraph characterizes a fourteenth example of the subject matter disclosed herein, wherein the fourteenth example also encompasses the thirteenth example above.

[0057] Similar to first boundary edge 162 described above, second boundary edge 164, extending from curved boundary edge second end 168, forms a vertex at which second boundary edge 164 and curved boundary edge second end 168 intersect. Specifically, second boundary edge 164 and curved boundary edge second end 168 form a convex vertex or corner that avoids stress risers, which are inherently formed in inner or concave vertices or corners. Fewer or no stress risers reduce fatigue of protrusion 130 and can extend the service life of protrusion 130.

[0058] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 、 Figure 10A and Figure 10B , first boundary edge 162 is parallel to second boundary edge 164. The foregoing of this paragraph characterizes a fifteenth example of the subject matter disclosed herein, wherein the fifteenth example also encompasses the fourteenth example above.

[0059] Orienting first boundary edge 162 parallel to second boundary edge 164 simplifies and reduces manufacturing costs for protrusion 130 and the adjacent first main landing gear door 140. Furthermore, first and second boundary edges 162, 164, oriented parallel to each other, are spaced apart by a distance that is substantially equal to the diameter of first tire 160. Spacing first and second boundary edges 162, 164 apart in this manner enables first main landing gear door 140 to have a width that is substantially equal to the diameter of first tire 160. First main landing gear door 140 sized in this manner is lightweight, resulting in a reduced weight for aircraft subassembly 100.

[0060] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 and Figure 10B , first boundary edge 162, second boundary edge 164, and curved boundary edge 144 together form a profile. The profile includes at least one curve or a combination of at least one straight line and at least one curve. The profile also lacks an interior angle having a vertex. The foregoing content of this paragraph characterizes a sixteenth example of the subject matter disclosed herein, wherein the sixteenth example also encompasses the fifteenth example above.

[0061] As used herein, the term "profile" is intended to describe a profile that is designed to minimize stress effects and lacks interior corners with vertices. As used herein, the term "vertices" describes an extreme local curvature or point where two curves, two straight lines, or a curve and a straight line intersect. As described herein, the profile formed by first boundary edge 162, second boundary edge 164, and curved boundary edge 144 forms two convex vertices or corners, thereby avoiding stress risers that are inherently formed in interior or concave vertices or corners. Fewer or no stress risers reduce fatigue of protrusion 130 and can extend the service life of protrusion 130.

[0062] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 and Figure 10B , the first boundary edge 162 and the second boundary edge 164 are linear. The foregoing content of this paragraph characterizes a seventeenth example of the subject matter disclosed herein, wherein the seventeenth example also encompasses any of the twelfth to sixteenth examples above.

[0063] The linear first boundary edge 162 and the second boundary edge 164 are easier and less expensive to manufacture than non-linear edges.

[0064] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 、 Figure 10A and Figure 10B , first boundary edge 162, second boundary edge 164, and curved boundary edge 144 together form a profile. The profile includes at least one curve or a combination of at least one straight line and at least one curve. The profile also lacks an interior angle having a vertex. The foregoing content of this paragraph characterizes an eighteenth example of the subject matter disclosed herein, wherein the eighteenth example also encompasses the seventeenth example above.

[0065] As described herein, the profile formed by first boundary edge 162, second boundary edge 164, and curved boundary edge 144 forms two convex vertices or corners, thereby avoiding stress risers inherently formed in inner or concave vertices or corners. Fewer or no stress risers reduce fatigue of protrusion 130 and can extend the service life of protrusion 130.

[0066] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 3 The first main landing gear assembly 106 is selectively movable about a first pivot axis 118 between a retracted position and an extended position (inclusive). The first pivot axis 118 is 65.0 inches to 75.0 inches from a virtual plane of symmetry 120. The foregoing of this paragraph characterizes a nineteenth example of the subject matter disclosed herein, which nineteenth example also encompasses the eighteenth example above.

[0067] As used herein, "virtual" means having the attributes of a physical entity without possessing its physical form. For example, a virtual reference plane is an intangible or imaginary plane, rather than a physical plane, relative to which the position and / or orientation of, for example, other physical and / or intangible entities can be defined. Positioning first pivot axis 118 at the described distance from virtual symmetry plane 120 allows sufficient space for first main landing gear assembly 106 to rotate between the retracted and extended positions, inclusive, but the described distance is not so great that first main landing gear assembly 106 occupies more space within nose 130 than is necessary.

[0068] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 3 , the first pivot axis 118 is 70.5 inches from the virtual plane of symmetry 120. The foregoing of this paragraph characterizes a twentieth example of the subject matter disclosed herein, wherein the twentieth example also encompasses the nineteenth example above.

[0069] As described herein, first pivot axis 118 is positioned as close as possible to virtual plane of symmetry 120 to allow sufficient space for first main landing gear assembly 106 to move to the extended position, but also allows first main landing gear assembly 106 to occupy the smallest possible volume so that protrusion 130 can be as small as possible.

[0070] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 3 When first main landing gear assembly 106 is in the extended position and second main landing gear assembly 112 is in the extended position, first main landing gear assembly 106 and second main landing gear assembly 112 define a wheelbase 124 between first wheel mid-plane 113 and second wheel mid-plane 119. Wheelbase 124 has a length of 170 inches to 180 inches. The foregoing content of this paragraph characterizes a twenty-first example of the subject matter disclosed herein, wherein the twenty-first example also encompasses any of the eighteenth to twentieth examples above.

[0071] As shown in the figure, first wheel midplane 113 and second wheel midplane 119 divide first wheel 110 and second wheel 116 into two equal parts, respectively. As used herein, the term "wheelbase" is used to describe the distance between first wheel midplane 113 and second wheel midplane 119, and is also referred to as "wheelbase." The wheelbase 124 described herein enables an aircraft based on aircraft subassembly 100 to have improved maneuverability while taxiing.

[0072] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 3 , the length of the wheelbase 124 is 172 inches. The foregoing of this paragraph characterizes a twenty-second example of the subject matter disclosed herein, wherein the twenty-second example also encompasses the twenty-first example above.

[0073] As described herein, wheelbase 124 improves the maneuverability of the aircraft based on aircraft subassembly 100 while taxiing.

[0074] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 4 , the first main landing gear assembly 106 and the second main landing gear assembly 112 are in the retracted position, and the shortest distance D1 between the first wheel 110 and the second wheel 116 is 12 inches to 20 inches. The foregoing content of this paragraph represents a twenty-third example of the subject matter disclosed herein, wherein the twenty-third example also encompasses any of the above eighteenth to twenty-second examples.

[0075] Positioning first wheel 110 near second wheel 116 occupies less space within protrusion 130 and allows protrusion 130 to be smaller than if first wheel 110 and second wheel 116 were positioned farther apart. In this configuration, protrusion 130 exhibits a low drag coefficient on aircraft subassembly 100 while the aircraft based on aircraft subassembly 100 is airborne. Reducing the drag coefficient of protrusion 130 increases the maximum speed and fuel efficiency of the aircraft based on aircraft subassembly 100. Furthermore, protrusion 130 reduces the weight of aircraft subassembly 100 and further improves the fuel efficiency of the associated aircraft.

[0076] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 4, first main landing gear assembly 106 and second main landing gear assembly 112 are in the retracted position, and the shortest distance D1 between first wheel 110 and second wheel 116 is 16.1 inches. The foregoing content of this paragraph characterizes a twenty-fourth example of the subject matter disclosed herein, wherein the twenty-fourth example also encompasses the twenty-third example above.

[0077] As described herein, the closer the first wheel 110 is positioned to the second wheel 116, the smaller the protrusion 130 can be. In this configuration, the protrusion 130 exhibits a low drag coefficient on the aircraft subassembly 100. Further reducing the drag coefficient of the protrusion 130 enables an increase in the maximum speed and fuel efficiency of an aircraft based on the aircraft subassembly 100. Furthermore, the protrusion 130 of the twenty-fourth example further reduces the weight of the aircraft subassembly 100 and further improves the fuel efficiency of the associated aircraft.

[0078] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 5 and Figure 10A , first wheel 110 includes a first tire 160 having a certain diameter. When first main landing gear assembly 106 is in the retracted position and first main landing gear door 140 is in the closed position, first circumferential closed opening 152 has a first diameter that is 1% to 5% larger than the diameter of first tire 160. The foregoing content of this paragraph characterizes a twenty-fifth example of the subject matter disclosed herein, wherein the twenty-fifth example also encompasses any of the eighteenth to twenty-fourth examples above.

[0079] As described herein, when first main landing gear assembly 106 is in the retracted position, first circumferentially closed opening 152 is circular to correspond to the shape of first tire 160. Because first tire 160 is exposed during flight, the closer the size and shape of first circumferentially closed opening 152 approximates that of first tire 160, the less wind resistance caused by first circumferentially closed opening 152. In this configuration, first tire 160 occupies a significant area of first circumferentially closed opening 152 and itself acts as a portion of protrusion 130, which reduces the drag coefficient of protrusion 130. Reducing the drag coefficient of protrusion 130 enables an increase in the maximum speed of an aircraft based on aircraft subassembly 100 and increases fuel efficiency.

[0080] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 13First main landing gear assembly 106 includes a main trunnion brace 170, which includes a main trunnion brace first end 172 and a main trunnion brace second end 174. First main landing gear assembly 106 also includes an oil damping strut 176, which includes an outer cylinder 178 coupled to main trunnion brace 170 between main trunnion brace first end 172 and main trunnion brace second end 174. Oil damping strut 176 also includes an inner cylinder 180 capable of telescopic movement relative to outer cylinder 178. First main landing gear assembly 106 also includes a shaft 181 coupled between inner cylinder 180 and first wheel 110, and an actuator 182 coupled to main trunnion brace 170 and fuselage structure 102. Actuator 182 is configured to move first main landing gear assembly 106 between a retracted position and an extended position (inclusive) about first pivot axis 118, which extends from main trunnion brace first end 172 and main trunnion brace second end 174 through main trunnion brace 170. The foregoing of this paragraph characterizes a twenty-sixth example of the subject matter disclosed herein, which also encompasses any of the eighteenth through twenty-fifth examples above.

[0081] Positioning outer cylinder 178 between main trunnion brace first end 172 and main trunnion brace second end 174 enables landing forces to be evenly distributed to main trunnion brace first end 172 and main trunnion brace second end 174. Evenly distributing these forces results in reduced component fatigue and extends the service life of at least main trunnion brace 170 and oil buffer strut 176.

[0082] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 13 , outer cylinder 178 has outer cylinder first end 184 and outer cylinder second end 186, and main trunnion brace 170 is disposed between outer cylinder first end 184 and outer cylinder second end 186. The foregoing of this paragraph characterizes a twenty-seventh example of the subject matter disclosed herein, wherein the twenty-seventh example also encompasses the twenty-sixth example above.

[0083] Positioning main trunnion brace 170 between outer cylinder first end 184 and outer cylinder second end 186, rather than at the top end of outer cylinder 178, reduces the height of first main landing gear assembly 106 when first main landing gear assembly 106 is in the deployed position. Reducing the height of first main landing gear assembly 106 enables protrusion 130 to have a relatively small size, thereby reducing the overall weight and drag coefficient of protrusion 130 and increasing the fuel efficiency of an aircraft based on aircraft subassembly 100. Furthermore, reducing the height of first main landing gear assembly 106 enables landing gear bay section 158 to have a smaller size, thereby increasing the size of cargo bay section 156, thereby enabling an aircraft based on aircraft subassembly 100 to carry a larger amount of cargo for increased operational efficiency.

[0084] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 13 , the oil damping strut 176 is tilted relative to the first pivot axis 118. The foregoing of this paragraph characterizes a twenty-eighth example of the subject matter disclosed herein, wherein the twenty-eighth example also encompasses the twenty-sixth example above.

[0085] The angled orientation of the oil damping struts 176 relative to the first pivot axis 118 allows landing forces to be evenly distributed between at least the oil damping struts 176, the main trunnion braces 170, and the plurality of first frame members 109. Evenly distributing these forces results in less part fatigue and extends the useful life of the first main landing gear assembly 106 and the fuselage structure 102.

[0086] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 13 The first main landing gear assembly 106 further includes a pair of deployment links 188 coupled between the first main landing gear door 140 and the main trunnion brace 170. The foregoing content of this paragraph characterizes a twenty-ninth example of the subject matter disclosed herein, wherein the twenty-ninth example also encompasses any of the twenty-sixth to twenty-eighth examples above.

[0087] Coupling the deployment link 188 to the main trunnion brace 170 enables the deployment link 188 to move synchronously with the main trunnion brace 170, and only a single actuator, such as the actuator 182, is required to extend the first main landing gear assembly 106 and open the first main landing gear door 140. When the actuator 182 extends, the main trunnion brace 170 rotates about the first pivot axis 118, and the deployment link 188 rotates with the outer surface of the main trunnion brace 170 to move the first main landing gear door 140 to the open position.

[0088] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 13 , the first main landing gear assembly 106 further includes a side brace 190 coupled between the outer cylinder 178 and the fuselage mechanism 102. The foregoing content of this paragraph represents the thirtieth example of the subject matter disclosed herein, wherein the thirtieth example also encompasses any one of the twenty-sixth to twenty-ninth examples above.

[0089] Side brace 190 also enables landing forces to be evenly distributed from first main landing gear assembly 106 to fuselage structure 102. As described herein, evenly distributing these forces results in less part fatigue and extends the useful life of first main landing gear assembly 106 and fuselage structure 102.

[0090] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 2 and Figure 5 The fuselage structure 102 has a fuselage structure longitudinal axis 122, a first fuselage structure end 126, a second fuselage structure end 128, and a fuselage structure length L1 extending from the first fuselage structure end 126 to the second fuselage structure end 128 along the fuselage structure longitudinal axis 122. An auxiliary wing 103 is located between the first fuselage structure end 126 and the second fuselage structure end 128. The protrusion 130 has a protrusion front side 132, a protrusion rear side 134, and a protrusion length L2 extending from the protrusion front side 132 to the protrusion rear side 134 along the fuselage structure longitudinal axis 122. The protrusion length L2 is 10% to 15% of the fuselage structure length L1. The foregoing content of this paragraph characterizes a thirty-first example 31 of the subject matter disclosed herein, wherein the thirty-first example also encompasses any of the first to thirtieth examples.

[0091] A relatively small ratio of protrusion length L2 to fuselage length L1 is associated with a relatively small size of protrusion 130. In this configuration, protrusion 130 exhibits a low drag coefficient on aircraft subassembly 100 while an aircraft based on aircraft subassembly 100 is airborne. Reducing the drag coefficient of protrusion 130 improves the performance of aircraft subassembly 100 as it relates to the speed and fuel efficiency of the associated aircraft. Specifically, a low drag coefficient enables an aircraft based on aircraft subassembly 100 to have an increased maximum speed and improved fuel efficiency. Furthermore, the ratio of protrusion length L2 to fuselage length L1 described herein enables protrusion 130 to be as small as possible, thereby reducing the weight of protrusion 130 and further increasing the fuel efficiency of an aircraft based on aircraft subassembly 100.

[0092] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 2 and Figure 5 , the protrusion length L2 is 11.5% to 13.5% of the fuselage structure length L1. The foregoing content of this paragraph characterizes a thirty-second example of the subject matter disclosed herein, wherein the thirty-second example also encompasses the thirty-first example above.

[0093] As described herein, a small ratio of the protrusion length L2 to the fuselage length L1 is associated with a relatively low drag coefficient for the protrusion 130. Further reducing the drag coefficient of the protrusion 130 improves the performance of the aircraft subassembly 100 as it relates to the speed and fuel efficiency of the associated aircraft. Specifically, a low drag coefficient enables an increase in the maximum speed and increased fuel efficiency of an aircraft based on the aircraft subassembly 100.

[0094] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 2 and Figure 5 , the protrusion length L2 is 12.0% to 13.0% of the fuselage structure length L1. The foregoing content of this paragraph characterizes a thirty-third example of the subject matter disclosed herein, wherein the thirty-third example also encompasses the thirty-second example above.

[0095] As described herein, a small ratio of the protrusion length L2 to the fuselage length L1 is associated with a relatively low drag coefficient for the protrusion 130. Further reducing the drag coefficient of the protrusion 130 improves the performance of the aircraft subassembly 100 as it relates to the speed and fuel efficiency of the associated aircraft. Specifically, a low drag coefficient enables an increase in the maximum speed and increased fuel efficiency of an aircraft based on the aircraft subassembly 100.

[0096] For illustrative purposes only and not by way of limitation, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 2 and Figure 5 , the protrusion length L2 is 12.4% of the fuselage structure length L1. The foregoing of this paragraph characterizes a thirty-fourth example of the subject matter disclosed herein, wherein the thirty-fourth example also encompasses the thirty-third example above.

[0097] As described herein, a small ratio of the protrusion length L2 to the fuselage length L1 is associated with a relatively low drag coefficient for the protrusion 130. Further reducing the drag coefficient of the protrusion 130 improves the performance of the aircraft subassembly 100 as it relates to the speed and fuel efficiency of the associated aircraft. Specifically, a low drag coefficient enables an increase in the maximum speed and increased fuel efficiency of an aircraft based on the aircraft subassembly 100.

[0098] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 7 The fuselage structure 102 further includes a cargo hold section 156 having a cargo hold section cross-sectional area CSA1 and a landing gear well section 158 having a landing gear well section cross-sectional area CSA2. Cargo hold section 156 and landing gear well section 158 are separated by a cargo hold floor 157. The protrusion 130 has a protrusion section cross-sectional area CSA3. The protrusion section cross-sectional area CSA3, the cargo hold section cross-sectional area CSA1, and the landing gear well section cross-sectional area CSA2 together form an aircraft cross-sectional area CSA4. The protrusion section cross-sectional area CSA3 is 25% to 35% of the aircraft cross-sectional area CSA4. The foregoing content of this paragraph represents a thirty-fifth example of the subject matter disclosed herein, wherein the thirty-fifth example also encompasses any of the first to thirty-fourth examples above.

[0099] A relatively small ratio of protrusion cross-sectional area CSA3 to aircraft cross-sectional area CSA4 is associated with a relatively small size of protrusion 130. In this configuration, protrusion 130 exhibits a low drag coefficient on aircraft subassembly 100 while the aircraft based on aircraft subassembly 100 is airborne. Reducing the drag coefficient of protrusion 130 enables an increase in the maximum speed and fuel efficiency of the aircraft based on aircraft subassembly 100. Furthermore, the ratio of protrusion cross-sectional area CSA3 to aircraft cross-sectional area CSA4 described herein enables an increase in the size of cargo compartment 156, enabling aircraft subassembly 100 to carry a larger amount of cargo, thereby increasing the operational efficiency of the associated aircraft.

[0100] For illustrative purposes only and not by way of limitation, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 7 , the protrusion cross-sectional area CSA3 is 27.5% to 32.5% of the aircraft cross-sectional area CSA4.The foregoing of this paragraph characterizes a thirty-sixth example of the subject matter disclosed herein, wherein the thirty-sixth example also encompasses the thirty-fifth example above.

[0101] As described herein, a low ratio of the protrusion cross-sectional area CSA3 to the aircraft cross-sectional area CSA4 is associated with a relatively low drag coefficient for the protrusion 130. Further reducing the drag coefficient of the protrusion 130 enables an increase in the maximum speed and fuel efficiency of an aircraft based on the aircraft subassembly 100. Furthermore, reducing the ratio of the protrusion cross-sectional area CSA3 to the aircraft cross-sectional area CSA4 increases the size of the cargo hold portion 156, enabling the aircraft subassembly 100 to carry a larger amount of cargo to increase the operating efficiency of the associated aircraft.

[0102] For illustrative purposes only and not by way of limitation, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 7 , the protrusion cross-sectional area CSA3 is 29.4% of the aircraft cross-sectional area CSA4.The foregoing of this paragraph characterizes a thirty-seventh example of the subject matter disclosed herein, wherein the thirty-seventh example also encompasses the thirty-sixth example above.

[0103] As described herein, a low ratio of the protrusion cross-sectional area CSA3 to the aircraft cross-sectional area CSA4 is associated with a relatively low drag coefficient for the protrusion 130. Further reducing the drag coefficient of the protrusion 130 enables an increase in the maximum speed and fuel efficiency of an aircraft based on the aircraft subassembly 100. Furthermore, reducing the ratio of the protrusion cross-sectional area CSA3 to the aircraft cross-sectional area CSA4 increases the size of the cargo hold portion 156, enabling the aircraft subassembly 100 to carry a larger amount of cargo to increase the operating efficiency of the associated aircraft.

[0104] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 7 , the cargo hold portion cross-sectional area CSA1 is twice the protrusion portion cross-sectional area CSA3. The foregoing content of this paragraph characterizes a thirty-eighth example of the subject matter disclosed herein, wherein the thirty-eighth example also encompasses any one of the thirty-fifth to thirty-seventh examples above.

[0105] The larger the cargo compartment cross-sectional area CSA1 relative to the nose cross-sectional area CSA3 , the greater the cargo volume of the aircraft subassembly 100 .

[0106] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 7, the cargo hold cross-sectional area CSA1 is 60% to 65% of the aircraft cross-sectional area CSA4. The foregoing content of this paragraph characterizes the thirty-ninth example of the subject matter disclosed herein, wherein the thirty-ninth example also encompasses any of the thirty-fifth to thirty-eighth examples above.

[0107] The high cargo hold cross-sectional area CSA1 to aircraft cross-sectional area CSA4 ratio enables a larger cargo hold volume for the aircraft subassembly 100 , which enables an aircraft based on the aircraft subassembly 100 to carry a greater amount of cargo to increase the operational efficiency of the associated aircraft.

[0108] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 7 , the cargo hold cross-sectional area CSA1 is 62.2% of the aircraft cross-sectional area CSA4. The foregoing content of this paragraph characterizes the fortieth example of the subject matter disclosed herein, wherein the fortieth example also encompasses the thirty-ninth example above.

[0109] As described herein, a high cargo hold cross-sectional area CSA1 to aircraft cross-sectional area CSA4 ratio is associated with a greater cargo hold volume for an aircraft based on aircraft subassembly 100. Further reducing this ratio enables aircraft subassembly 100 to carry a greater amount of cargo to increase the operating efficiency of the associated aircraft.

[0110] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 7 , the landing gear compartment cross-sectional area CSA2 is 5.0% to 10.0% of the aircraft cross-sectional area CSA4. The foregoing content of this paragraph characterizes the forty-first example of the subject matter disclosed herein, wherein the forty-first example also encompasses any one of the thirty-fifth to fortieth examples above.

[0111] The ratio of the landing gear well section cross-sectional area CSA2 to the aircraft cross-sectional area CSA4 represents how much of the aircraft cross-sectional area CSA4 is occupied by the landing gear well section 158. A low ratio describes the smaller size of the landing gear well section 158 relative to the relatively large cargo hold section 156. As described herein, the larger the cargo hold section 156, the greater the cargo volume of the aircraft based on the aircraft subassembly 100. Furthermore, positioning the landing gear well section 158 below the cargo hold floor 157 further reduces the landing gear well section cross-sectional area CSA2 and increases the cargo hold section cross-sectional area CSA1.

[0112] For illustrative purposes only and not limiting, reference is generally made to Figure 1A 、 Figure 1B and Figure 1C and with particular reference to e.g. Figure 7 , the landing gear compartment cross-sectional area CSA2 is 8.4% of the aircraft cross-sectional area CSA4.The foregoing content of this paragraph characterizes a forty-second example of the subject matter disclosed herein, wherein the forty-second example also encompasses the forty-first example above.

[0113] As described herein, a low ratio of the landing gear well section cross-sectional area CSA2 to the aircraft cross-sectional area CSA4 is associated with a smaller landing gear well section 158, which corresponds to a relatively larger cargo hold section 156. Furthermore, positioning the landing gear well section 158 below the cargo hold floor 157 further reduces the landing gear well section cross-sectional area CSA2 and increases the cargo hold section cross-sectional area CSA1. As described herein, the larger the cargo hold section 156, the greater the cargo capacity of the aircraft subassembly 100.

[0114] Available in Figure 16 Aircraft manufacturing and service method 1100 is shown and Figure 17 Examples of the subject matter disclosed herein are described in the context of an aircraft 102 as shown. During pre-production, the exemplary method 1100 may include specification and design of the aircraft 1102 (block 1104) and material procurement (block 1106). During production, component and subassembly manufacturing (block 1108) and system integration (block 1110) of the aircraft 1102 may occur. Thereafter, the aircraft 102 may be certified and delivered (block 1112) for service (block 1114). When undergoing maintenance, the aircraft 1102 may be scheduled for routine maintenance and servicing (block 1116). Routine maintenance and servicing may include modification, reconfiguration, refurbishment, etc. of one or more systems of the aircraft 1102.

[0115] The various processes of exemplary method 1100 may be performed or executed by a system integrator, a third party, and / or an operator (e.g., a customer). For the purposes of this description, a system integrator may include, but is not limited to, any number of aircraft manufacturers and major system subcontractors; a third party may include, but is not limited to, any number of suppliers, subcontractors, and vendors; and an operator may be an airline, a leasing company, a military entity, a service organization, etc.

[0116] like Figure 17As shown in FIG, an aircraft 1102 produced using exemplary method 1100 may include an airframe 1118 having a plurality of high-level systems 1120 and an interior 1122. Examples of high-level systems 1120 include one or more of a propulsion system 1124, an electrical system 1126, a hydraulic system 1128, and an environmental system 1130. Any number of other systems may be included. Although an aerospace example is shown, the principles disclosed herein may be applied to other industries such as the automotive industry. Thus, in addition to aircraft 1102, the principles disclosed herein may be applicable to other vehicles, such as land vehicles, marine vehicles, spacecraft, and the like.

[0117] The apparatus and methods shown or described herein may be employed during any one or more of the stages of manufacturing and service method 1100. For example, components or subassemblies corresponding to component and subassembly manufacturing (block 1108) may be fabricated or manufactured in a manner similar to how components or subassemblies are produced while aircraft 1102 is in service (block 1114). Additionally, one or more examples of apparatus, method, or combination thereof may be utilized during production stages 1108 and 1110, for example, to significantly expedite assembly of aircraft 1102 or reduce the cost of aircraft 1102. Similarly, for example, and not limitation, one or more examples of apparatus or method implementations or combination thereof may be utilized while aircraft 1102 is in service (block 1114) and / or undergoes maintenance and service (block 1116).

[0118] The different examples of the devices and methods disclosed herein include various components, features, and functions. It should be understood that the various examples of the devices and methods disclosed herein may include any of the components, features, and functions of any of the other examples of the devices and methods disclosed herein in any combination, and all such possibilities are intended to fall within the scope of the present disclosure.

[0119] Many modifications of the examples set forth herein will come to mind to one skilled in the art to which this disclosure pertains having the benefit of the teachings presented in the foregoing descriptions and the associated drawings.

[0120] Therefore, it is to be understood that the subject matter disclosed herein is not limited to the specific examples illustrated, and modifications and other examples are intended to be included within the scope of the appended claims. Furthermore, while the foregoing description and associated drawings describe examples of the subject matter disclosed herein in the context of certain illustrative combinations of elements and / or functions, it should be understood that different combinations of elements and / or functions may be provided by alternative implementations without departing from the scope of the appended claims. Therefore, the reference numerals in parentheses in the appended claims are provided for illustrative purposes only and are not intended to limit the scope of the claimed subject matter to the specific examples provided in this disclosure.

Claims

1. An aircraft subassembly (100), comprising a fuselage structure (102), the fuselage structure (102) having a first side (108) comprising a plurality of first frame members (109) and a second side (114) comprising a plurality of second frame members (115), the aircraft subassembly (100) further comprising a wing (103) and a main landing gear system (104), the wing (103) being attached to the fuselage structure (102) and the main landing gear system (104). 4) having a pair of wheels (107) consisting of a first wheel (110) and a second wheel (116), wherein the first wheel (110) has a first wheel azimuth rotational symmetry axis (111) and a first wheel middle plane (113) perpendicular to the first wheel azimuth rotational symmetry axis (111), and the second wheel (116) has a second wheel azimuth rotational symmetry axis (117) and a second wheel middle plane (119) perpendicular to the second wheel azimuth rotational symmetry axis (117), and the main landing gear system (104) further comprises: A protrusion (130) connected to and extending outwardly from the fuselage structure (102) and comprising: Central Department (131); a first main landing gear door (140) movable relative to the central portion (131) between a closed position and an open position, inclusive; and a second main landing gear door (142) movable relative to the central portion (131) between a closed position and an open position, inclusive; a first main landing gear assembly (106) connected to the first wheel (110); and a second main landing gear assembly (112) connected to the second wheel (116), The first main landing gear assembly (106) includes a main trunnion strut (170), the main trunnion strut (170) includes a main trunnion strut first end (172) and a main trunnion strut second end (174), the first main landing gear assembly (106) further includes an oil buffer strut (176), the oil buffer strut (176) includes an outer cylinder (178), the outer cylinder (178) is connected to the main trunnion strut (170) between the main trunnion strut first end (172) and the main trunnion strut second end (174), the outer cylinder (178) has an outer cylinder first end (184) and an outer cylinder second end (186), and the main trunnion strut (170) is arranged between the outer cylinder first end (184) and the outer cylinder second end (186).

2. The aircraft subassembly (100) of claim 1, further comprising a virtual symmetry plane (120) equidistant from the first side (108) of the fuselage structure (102) and the second side (114) of the fuselage structure (102), and wherein: The central portion (131) of the protrusion (130) includes: a first circumferential opening cut (149); and A second circumferential opening cutout (151); and The virtual symmetry plane (120) passes between the first circumferential opening cutout (149) and the second circumferential opening cutout (151).

3. The aircraft subassembly (100) according to claim 2, wherein: The first circumferential opening cut (149) is non-circular.

4. The aircraft subassembly (100) according to claim 3, wherein: The fuselage structure (102) has a fuselage outer surface (136), and the fuselage outer surface (136) has a fuselage surface area (SA1); The protrusion (130) has a protrusion outer surface (138), and the protrusion outer surface (138) has a protrusion surface area (SA2); and The protrusion surface area (SA2) is 10% to 15% of the fuselage surface area (SA1).

5. The aircraft subassembly (100) of claim 4, wherein: The first main landing gear door (140) has a first main landing gear door surface area (SA3); The second main landing gear door (142) has a second main landing gear door surface area (SA4); and The first main landing gear door surface area (SA3) and the second main landing gear door surface area (SA4) form a portion of the nose surface area (SA2).

6. The aircraft subassembly (100) according to claim 4 or 5, wherein: When the first main landing gear door (140) is in the closed position, the first main landing gear door (140) of the protruding portion (130) and the central portion (131) together form a first circumferential closed opening (152); The first circumferentially closed opening (152) has a first opening rotational symmetry axis (153) perpendicular to a virtual plane, in which a projection of the first circumferentially closed opening (152) has a maximum area; When the second main landing gear door (142) is in the closed position, the second main landing gear door (142) of the protrusion (130) and the central portion (131) together form a second circumferential closed opening (154); The second circumferentially closed opening (154) is circumferentially closed and has a second open rotational symmetry axis (155) perpendicular to a virtual plane in which a projection of the second circumferentially closed opening (154) has a maximum area; The first main landing gear assembly (106) is connected to at least one of the plurality of first frame members (109), is pivotable relative to the at least one of the plurality of first frame members (109), and is selectively movable between a retracted position and an extended position, inclusive of the retracted position and the extended position; wherein, when the first main landing gear assembly (106) is in the retracted position, the first main landing gear door (140) is in the closed position, and the first wheel azimuth rotational symmetry axis (111) and the first opening rotational symmetry axis (153) are collinear; When the first main landing gear assembly (106) is in the extended position, the first main landing gear door (140) is in the open position, and the first wheel azimuth rotational symmetry axis (111) and the first opening rotational symmetry axis (153) are non-collinear; The second main landing gear assembly (112) is connected to at least one of the plurality of second frame members (115), is pivotable relative to the at least one of the plurality of second frame members (115), and is selectively movable between a retracted position and an extended position, inclusive of the retracted position and the extended position; When the second main landing gear assembly (112) is in the retracted position, the second main landing gear door (142) is in the closed position and the second wheel azimuth rotational symmetry axis (117) is collinear with the second opening rotational symmetry axis (155); and When the second main landing gear assembly (112) is in the extended position, the second main landing gear door (142) is in the open position, and the second wheel azimuth rotational symmetry axis (117) is non-collinear with the second opening rotational symmetry axis (155).

7. The aircraft subassembly (100) according to claim 6, wherein: The protrusion surface area (SA2) does not include the area of the first circumferentially closed opening (152) and the area of the second circumferentially closed opening (154).

8. The aircraft subassembly (100) according to claim 7, wherein: The first circumferential open cut (149) further comprises a curvilinear boundary edge (144), at least a portion of which forms only a portion of the first circumferential closed opening (152).

9. The aircraft subassembly (100) according to claim 8, wherein: The first circumferential opening cut (149) further includes a first boundary edge (162) extending from the curvilinear boundary edge (144).

10. The aircraft subassembly (100) according to claim 9, wherein: The first circumferential opening cut (149) further includes a second boundary edge (164) extending from the curvilinear boundary edge (144).

Images