Landing gear door system for landing gear compartment
The pivotable V-shaped door system for landing gear compartments addresses drag and vibration issues by maintaining aerodynamic continuity, enhancing flight dynamics and reducing wear through smooth door transitions.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- THE BOEING CO
- Filing Date
- 2021-12-17
- Publication Date
- 2026-05-14
AI Technical Summary
Conventional retractable nose landing gear systems experience undesirable drag, turbulence, and vibrations due to the exposure of exit doors to high-speed airflow during flight, which impairs flight dynamics and causes stress and wear on the doors.
A landing gear door system with a pivotable door configured to form a V-shape, allowing the door panel to rotate into the landing gear compartment, providing aerodynamic continuity with the aircraft skin in the closed position and exposing the opening in the open position, utilizing a mechanism with connecting members, levers, and actuators to facilitate smooth transitions.
Minimizes air drag and reduces vibrations by maintaining aerodynamic continuity during flight, while enabling efficient extension and retraction of the landing gear without disrupting airflow.
Smart Images
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Abstract
Description
[Technical Field]
[0001] Cross-reference of related applications This application claims priority to U.S. Provisional Application No. 63 / 135,294, filed on 8 January 2021, which is incorporated herein by reference in its entirety.
[0002] This disclosure relates to a landing gear door system for an aircraft landing gear compartment. [Background technology]
[0003] Conventional nose landing gear for aircraft may be either fixed or retractable. While fixed landing gear designs are simpler, their protrusion into the airflow during flight impairs flight dynamics and causes undesirable drag, turbulence, and vibration, imposing stress and wear on the landing gear. Retractable landing gear, on the other hand, may retract into the nose or fuselage after takeoff, thus avoiding exposure to the airflow during flight. Furthermore, when the nose landing gear is retracted, the opening through which the landing gear retracts is typically covered by one or more hinged doors whose outer surfaces closely match the shape and curvature of the surrounding fuselage. However, such retractable nose landing gear systems typically require the placement of one or more doors when the landing gear is extended for landing. This means that one or more doors open outward from the fuselage and therefore into the airflow. Similar to the design of fixed landing gear, such exposure of the exit door to high-speed airflow impairs flight dynamics and causes undesirable drag, turbulence, and vibrations that impose stress and wear on the exit door. [Overview of the project] [Means for solving the problem]
[0004] According to one embodiment, a landing gear door system for a landing gear compartment is a door pivotable around a pivot pin configured to be positioned longitudinally on the aircraft body, the door having a door panel rigidly connected to an arm such that the door panel and arm generally form a V shape when viewed longitudinally, and a mechanism for rotating the door around the pivot pin between a closed position configured such that the outer surface of the door panel provides aerodynamic continuity with the outer aircraft skin of the aircraft body and an open position in which the door is rotated into the landing gear compartment and the opening is exposed.
[0005] The door panel and arm may be rigidly connected to each other at the apex of the door, and a pivot pin may extend through the apex. The pivot pin may be configured to rotatably connect to one of the mounting structures in the outer aircraft skin and the landing gear compartment. The door panel may have an arched contour when viewed longitudinally to provide aerodynamic continuity with the outer aircraft skin in the closed position, and the arm may have a curved or bent contour when viewed longitudinally, in which case the curved or bent contour has a apex that extends away from the door panel.
[0006] The mechanism may be configured to be mounted within the landing gear compartment. The mechanism may include a connecting member having opposing first connecting member ends and second connecting member ends, in which case the first connecting member end is pivotably connected to an arm; a coupling device having opposing first coupling device ends and second coupling device ends, in which case the first coupling device end is pivotably connected to the second connecting member end; a lever having opposing first lever ends and second lever ends and a fulcrum between the first lever end and the second lever end, in which case the first lever end is pivotably connected to the second coupling device end and the fulcrum is configured to be rotatably connected to a first mounting point within the landing gear compartment; and an actuator rotatably connected to the second lever end and configured to selectively bias the second lever end in a first direction toward the opening and a second direction toward the opening.
[0007] At least one of the connecting member, coupling device, and lever portion between the pivot point and the second lever end may be configured to extend or retract in length. The landing gear door system may further include a strut having opposing first strut end and second strut end, the first strut end being pivotably connected to a first coupling device end and a second connecting member end, and the second strut end being pivotably connected to one of a second mounting point in the landing gear compartment and an outer aircraft skin. The strut may be configured to extend or retract in length, and the strut may include a strut extender configured to selectively bias the strut to extend or retract in length, or to allow the strut to extend or retract in length. The first lever end and the second coupling end can define a first joint between them; the first coupling end and the second connecting member end can define a second joint between them; and the first connecting member end and the arm can define a third joint between them, in which case the third joint is positioned substantially outside the straight line when the first joint, the second joint and the pivot pin are positioned substantially along a straight line.
[0008] According to another embodiment, a nose landing gear door system for a nose landing gear compartment is a door pivotable about a pivot pin configured to be longitudinally positioned on the aircraft body, the door having a door panel rigidly connected to an arm such that the door panel and the arm substantially form a V shape when viewed longitudinally, and a mechanism for rotating the door about the pivot pin between a closed position, in which the outer surface of the door panel is configured to provide aerodynamic continuity with the outer aircraft skin of the aircraft body, and an open position, in which the door is rotated into the nose landing gear compartment and the opening is exposed. The mechanism includes a connecting member having opposing first connecting member ends and second connecting member ends, in which case the first connecting member end is pivotably connected to an arm; a connecting device having opposing first coupling device ends and second coupling device ends, in which case the first coupling device end is pivotably connected to the second connecting member end; a lever having opposing first lever ends and second lever ends and a fulcrum between the first lever end and the second lever end, in which case the first lever end is pivotably connected to the second coupling device end and the fulcrum is configured to be rotatably connected to a first mounting point in the nose landing gear compartment; and an actuator rotatably connected to the second lever end and configured to selectively bias the second lever end in a first direction toward the opening and a second direction toward the opening.
[0009] At least one of the connecting member, coupling device, and lever portion between the pivot point and the second lever end may be configured to extend or retract in length. The nose landing gear door system may further include a strut having opposing first strut end and second strut end, in which case the first strut end is pivotably connected to a first coupling device end and a second connecting member end, and the second strut end is pivotably connected to one of a second mounting point in the nose landing gear compartment and an outer aircraft skin. The strut may include a strut extender configured to selectively bias the strut to extend or retract in length, or to allow the strut to extend or retract in length. The first lever end and the second coupling end can define a first joint between them; the first coupling end and the second connecting member end can define a second joint between them; and the first connecting member end and the arm can define a third joint between them, in which case the third joint is positioned substantially outside the straight line when the first joint, the second joint and the pivot pin are positioned substantially along a straight line.
[0010] In yet another embodiment, a nose landing gear door system for an aircraft includes (a) an aircraft body having a nose landing gear compartment enclosed by an outer aircraft skin; (b) a door pivotable about a longitudinally positioned pivot pin on the aircraft body, the door having a door panel rigidly connected to an arm such that the door panel and the arm form a V shape when viewed longitudinally; and (c) a mechanism for rotating the door about a pivot pin between a closed position in which the outer surface of the door panel provides aerodynamic continuity with the outer aircraft skin of the aircraft body and an open position in which the door is rotated into the nose landing gear compartment and an opening is exposed. In this embodiment, the mechanism includes: (i) a connecting member having opposing first connecting member end and second connecting member end, in which case the first connecting member end is pivotably connected to an arm; (ii) a connecting device having opposing first coupling device end and second coupling device end, in which case the first coupling device end is pivotably connected to the second connecting member end; (iii) a lever having opposing first lever end and second lever end, and a fulcrum between the first lever end and the second lever end, in which case the first lever end is pivotably connected to the second coupling device end, and the fulcrum is rotatably connected to a first mounting point in the nose landing gear compartment; and (iv) an actuator rotatably connected to the second lever end and configured to selectively bias the second lever end in a first direction toward the opening and a second direction toward the opening.
[0011] In this embodiment, the nose landing gear door system may further include a strut having opposing first strut ends and second strut ends, in which case the first strut end is pivotably connected to a first coupling end and a second connecting member end, and the second strut end is pivotably connected to one of a second mounting point in the nose landing gear compartment and an outer aircraft skin. In this embodiment, a first lever end and a second coupling end may define a first joint between them, a first coupling end and a second connecting member end may define a second joint between them, and a first connecting member end and an arm may define a third joint between them, in which case the third joint is positioned substantially outside the straight line when the first joint, the second joint and the pivot pin are positioned substantially along a straight line.
[0012] The above-mentioned features and advantages of this teaching, as well as other features and advantages, will be readily apparent from the following detailed description of some of the best modes and other embodiments for carrying out this teaching, as defined in the attached claims, when interpreted in relation to the attached drawings. [Brief explanation of the drawing]
[0013] [Figure 1] This is a schematic front view of the landing gear door system in the closed position. [Figure 2] This is a schematic front view of the landing gear door system in the open position. [Figure 3] This is a schematic front view of the landing gear door system located in the intermediate position. [Figure 4A] This figure shows a series of schematic front views of the landing gear door system, from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4B] This figure shows a series of schematic front views of the landing gear door system, from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4C]A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4D] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4E] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4F] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4G] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4H] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4I] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4J] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4K] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Figure 4L] A diagram showing a series of schematic front views of a landing gear door system from the closed position through various intermediate positions to the open position, and then from the open position through various other intermediate positions to the closed position. [Modes for carrying out the invention]
[0014] Referring here to the drawings, similar reference numerals in some figures indicate similar parts, and a landing gear door system 20 for the landing gear compartment 12 (for example, for an aircraft 15) is shown and described herein.
[0015] Figures 1 to 3 show schematic front views of the landing gear door system 20 in the closed position 100, the open position 104, and the intermediate position 108, respectively. As will be further described below, Figure 1 shows a first configuration using various telescopic sections 58, 68, 78, and 98, while Figures 2 to 3 show a second configuration without such telescopic sections 58, 68, 78, and 98.
[0016] Furthermore, in the lower left of each figure, there is a reference diagram showing the vertical direction 21 (represented by a “dot” or a circle containing a dot, indicating that the positive vertical direction is shown from the plane of each figure toward the observer), the horizontal direction 23 (represented by an arrow pointing to the right, indicating the positive or port-side horizontal direction), and the vertical direction 29 (represented by an upward-pointing arrow, indicating the positive or upward vertical direction). Note that the “dot” and the two arrows in this reference diagram indicate the positive vertical direction 21, horizontal direction 23, and vertical direction 29, but the opposite or negative directions are also implied (even if not explicitly shown). In the case of a conventional layout of a fixed-wing aircraft 15, the vertical direction 21 extends forward and aft and is parallel to the roll axis, the horizontal direction 23 extends port and starboard and is parallel to the pitch axis, and the vertical direction 29 extends upward and downward and is parallel to the yaw axis. Furthermore, the upper part of Figure 1 shows the downward direction 82 and the upward direction 84 (parallel to the vertical direction 29), as well as the in-aircraft direction 86 and the out-aircraft direction 88.
[0017] Conventional nose landing gear door systems require an exit arrangement of one or more hinged doors, but the landing gear door system 20 described herein offers the advantage of an entrance arrangement of one or more pivotable doors 22.
[0018] According to one embodiment, the landing gear door system 20 for the landing gear compartment 12 includes a door 22 that is pivotable around a pivot pin 44 configured to be positioned longitudinally 21 on the aircraft body 10. (The pivot pin 44 pivots around a longitudinal axis 46 that extends parallel to the longitudinal direction 21.) The door 22 has a door panel 24 rigidly connected to an arm 30 such that the door panel 24 and the arm 30 form a V-shape 40 when viewed longitudinally 21. The landing gear door system 20 also includes a mechanism 50 that rotates the door 22 around the pivot pin 44 (in the direction indicated by arrow 112) between (i) a closed position 100 configured such that the outer surface 27 of the door panel 24 provides aerodynamic continuity 102 with the outer aircraft skin 11 of the aircraft body 10, and (ii) an open position 104 in which the door 22 is rotated into the landing gear compartment 12 and an opening or opening 106 is exposed.
[0019] The door 22 and / or door panel 24 may be configured such that, in the closed position 100, the shape of the outer surface 27 of the door panel substantially matches the adjacent surrounding shape of the outer aircraft skin 11. In other words, with the door 22 in the closed position 100, the outer aircraft skin 11 and the outer surface 27 together provide a substantially smooth, uninterrupted, joined surface that minimizes air drag across this surface. On the other hand, when the door 22 is positioned in the open position 104, the opening or opening 106 to which the outer surface 27 was previously positioned becomes visible.
[0020] The door panel 24 and the arm 30 may be rigidly connected to each other at the apex portion 42 of the door 22, and a pivot pin 44 extends through the apex portion 42. The pivot pin 44 may be configured to rotatably connect to one of (i) the outer aircraft skin 11 and (ii) a mounting structure 14 in the landing gear compartment 12. The door panel 24 may be configured to have an arched contour 28 when viewed longitudinally 21 to provide the aforementioned aerodynamic continuity 102 with the outer aircraft skin 11 in the closed position 100. The arm 30 may have a curved or bent contour 36 when viewed longitudinally 21, in which case the curved or bent contour 36 has a apex 38 that extends away from the door panel 24.
[0021] The configuration shown in Figures 1 to 3 shows two roughly V-shaped doors 22 arranged in a mirror image configuration relative to each other. (However, it should be noted that the landing gear door system 20 may include only one door 22, not two.) Each door panel 24 includes opposing first edges 25 and second edges 26, each arm 30 includes opposing first arm ends 32 and second arm ends 34, and the apex portion 42 of each door 22 includes their respective second edges 26 and first ends 32. In the two-door configuration shown in the drawings, the first edges 25 of the two doors 22 can lean against each other and come into contact, abut, and / or seal in the closed position 100, so as to provide a smooth surface and aerodynamic continuity 102 therein.
[0022] The mechanism 50 may be configured to be installed inside the landing gear compartment 12. The mechanism 50 may (i) have connecting members of length L between them. 52 A connecting member 52 having an opposing first connecting member end 54 and a second connecting member end 56, in which case the first connecting member end 54 is pivotably connected to the arm 30, and (ii) a connecting device length L between them 60A connecting device 60 having an opposing first connecting device end 62 and a second connecting device end 64, wherein the first connecting device end 62 is pivotably connected to the second connecting member end 56, and (iii) (a lever portion length L between the second lever end 74 and the fulcrum 76) 78 A lever 70 having a first lever end 72 and a second lever end 74 facing each other (with a first lever end 72 and a second lever end 74), and a pivot point 76 between the first lever end 72 and the second lever end 74, wherein the first lever end 72 is pivotably connected to a second coupling end 64, and the pivot point 76 is configured to be rotatably connected to a first mounting point 16 in the landing gear compartment 12; and (iv) an actuator 80 rotatably connected to the second lever end 74 and configured to selectively bias the second lever end 74 in a first direction 82 toward the opening 106 and a second direction 84 toward the opening 106.
[0023] The actuator 80 may include a contact portion 81 that is rotatably connected to the second lever end 74, and a drive portion 83 that selectively biases or drives the contact portion 81 in a first direction 82 and a second direction 84. For example, the actuator 80 may be a linear actuator that selectively drives the second lever end 74 downward and upward. The drive portion 83 may be fixedly located within the landing gear compartment 12, while the contact portion 81 may be freely translated in the first direction 82 and the second direction 84 (e.g., downward and upward).
[0024] At least one of the connecting member 52, the coupling device 60, and the portion of the lever 70 between the pivot point 76 and the second lever end 74 may be configured to extend or retract in length. For example, the connecting member 52 may include each extendable portion 58, the coupling device 60 may include each extendable portion 68, and / or the lever 70 may include each extendable portion 78 (between the pivot point 76 and the second lever end 74). Each of these extendable portions 58, 68, and 78 may take various configurations such as shock absorbers and dampers, and their extension and retraction are restricted to act only along the length of the respective connecting member 52, coupling device 60, or lever 70.
[0025] The landing gear door system 20 comprises a first strut end 92, second strut ends 94 and 96 facing the first strut end 92, and a length L between the first strut end 92 and the second strut ends 94 and 96. 90 , L 91 The struts 90, 91 may further include the following: The first strut end 92 may be pivotably connected to the first coupling end 62 and the second connecting member end 56, and the second strut ends 94, 96 may be pivotably connected to one of the following: (i) a second mounting point 18 in the landing gear compartment 12, and (ii) an alternative second mounting point 19 defined or supported by the outer aircraft skin 11 (for example, on the inner surface or inner surface of the outer aircraft skin 11). Note that Figure 1 shows both of these possible connection configurations for the second strut ends 94, 96, utilizing a “short” strut 90 with a second strut end 94, shown on the left side of the drawing, and a “long” strut 91 with a second strut end 96, shown on the right side of the drawing. For example, the left-hand door 22 in the drawing has a second strut end 94 pivotably connected to a second mounting point 18 located within the landing gear compartment 12, while the right-hand door 22 in the drawing has a second strut end 96 pivotably connected to an alternative second mounting point 19 defined or supported by the outer aircraft skin 11. (The left side of the drawing also shows a dashed line representing the outline of a "long" strut 91 in the case where such a strut 91 is used instead of a "short" strut 90.)
[0026] Also, similar to the connecting member 52, the connecting device 60, and the portion of the lever 70 between the fulcrum 76 and the second lever end 74, the columns 90, 91 have a length L 90 , L 91 may be configured to be telescopic, and the columns 90, 91 have a length L 90 , L 91 Note that there may be a column extender 98 (which may also be referred to as a column telescopic portion 98) that selectively biases the columns 90, 91 so that the length L 90 , L 91 is telescopic, or is configured to allow the columns to be telescopic. When the phrase "biases or allows" is used in this specification, "biases" means "acts actively or causes actively", and "allows" means "lets passively or allows passively". For example, the column extender 98 may be selectively configured to actively bias the columns 90, 91 so that the length L 90 , L 91 is telescopic by means of electric, pneumatic, mechanical, magnetorheological or other actuations (note that such actuating means are not shown). Alternatively, the column extender 98 may be such that the columns 90, 91 have a length L
[0027] The first lever end 72 and the second coupling end 64 may define a first joint J1 between them; the first coupling end 62 and the second connecting member end 56 may define a second joint J2 between them; the first connecting member end 54 and the arm 30 may define a third joint J3 between them; and the second lever end 74 and the contact portion 81 of the actuator 80 may define a fourth joint J4. As shown in Figure 3, the landing gear door system 20 may be configured such that the third joint J3 is positioned substantially outside the straight line 110 (i.e., outward direction 88) when the first joint J1 and the second joint J2 and the pivot pin 44 are positioned substantially along the straight line 110.
[0028] During operation, the landing gear door system 20 may be positioned in the closed position 100 (Figure 1) after the aircraft 15 has taken off from the runway and the landing gear 13 has been retracted into the landing gear compartment 12. During normal flight, the landing gear door system 20 normally remains in the closed position 100, as a result the smooth outer aircraft skin 11 and outer surface 27 together provide aerodynamic continuity 102 and low drag. Then, immediately before landing, the landing gear door system 20 may be positioned in the open position 104 (Figure 2) so that the landing gear 13 can be extended through the opening 106 for landing. The landing gear door system 20 may remain in the open position 104 during landing and taxiing, in fact until the aircraft 15 takes off again. Note that each time the landing gear door system 20 moves between the closed position 100 and the open position 104, it also passes through a series of intermediate positions 108 (one example of which is shown in Figure 3).
[0029] To repeat the landing gear door system 20 between a closed position 100, an intermediate position 108, and an open position 104, the actuator 80 may be selectively actuated to move the contact portion 81 in a first direction 82 and a second direction 84 (e.g., downward and upward) so that the door 22 rotates around its pivot pin 44. This rotation of the door 22 is achieved by converting the linear motion of the actuator 80 into rotational motion of the door 22 via a series of fixed and movable connections between the actuator 80, the lever 70, the first mounting point 16, the coupling device 60, the connecting member 52, the door 22, and the pivot pin 44 (and optionally, the struts 90, 91 and the second mounting points 18, 19 as well).
[0030] For example, Figures 4A to 4L show a series of schematic diagrams illustrating how various elements of the mechanism 50 work together to convert the linear motion of the actuator 80 into the rotational motion of the door 22. Note that, in order to simplify the drawings and make it easier to see the sequence of movements from one drawing to the next, not all of the structures shown in Figures 1 to 3 are shown in Figures 4A to 4L. Also, for simplification and illustrative purposes, only the left side of the structures in Figures 1 to 3 is shown. Here, in Figures 4A to 4L, filled circles represent rotatably fixed connection points (i.e., at 19, 44, and 76), and white circles represent unfixed connection points (i.e., at J1, J2, J3, and J4). Also, note that the telescopic parts 58, 68, 78, and 98 are not shown in Figures 4A to 4L, but these elements may be included optionally. Furthermore, note that while Figure 4A includes reference numerals for several elements (e.g., arm 30, connecting member 52, coupling device 60, lever 70, support column 91, and their various ends 54, 56, 62, 64, 72, 74), these reference numerals are not repeated throughout Figures 4B to 4L.
[0031] In Figure 4A, the landing gear door system 20 is in the closed position 100, and the actuator 80 is not causing any movement. In Figure 4B, the actuator 80 begins to actuate the contact portion 81 downward (as indicated by the downward arrow), and in Figure 4C, the contact portion 81 begins to push the fourth joint J4 downward. As the fourth joint J4 is pushed downward, the first joint J1 rotates upward around the fixed pivot point 76, and similarly, as the first joint J1 moves upward, the second joint J2 also moves upward, and the third joint J3 rotates counterclockwise around the fixed pivot pin 44. Figure 4D shows the actuator 80 facilitating further downward movement of the fourth joint J4, which results in further upward movement of the first joint J1 and the second joint J2, as well as further counterclockwise rotation of the third joint J3 around the pivot pin 44. In the configuration shown in Figure 4D, the total length of the element between the first joint J1 and the pivot pin 44 reaches its maximum, at which point the actuator 80 stops biasing the fourth joint J4 downward. At this point, the counterclockwise rotational momentum of the third joint J3 (and door 22) acts to continue rotating the third joint J3 (and door 22) further counterclockwise around the pivot pin 44, and the actuator 80 switches from biasing the fourth joint J4 downward to biasing it upward.
[0032] Next, Figure 4E shows three simultaneous actions, to varying degrees: (i) the continuous counterclockwise movement of the third joint J3 (and door 22), (ii) the upward biasing of the actuator 80 on the fourth joint J4 (which also causes the first joint J1 to rotate downward), and (iii) the rightward force exerted on the second joint J2 by the optional supports 90, 91. This combination of actions facilitates further counterclockwise movement of the third joint J3 (and door 22). It should also be noted that the third joint J3 is positioned substantially outside the straight line 110 (as similarly shown in Figure 3), which also facilitates further counterclockwise movement of the third joint J3 (and door 22). Figure 4F shows the result of the continuous action and movement in Figure 4E, where the door 22 is fully rotated and the opening 106 is fully exposed. Figure 4G shows that the actuator 80 has stopped its upward biasing and the landing gear door system 20 is in the fully open position 104. In this position, the landing gear 13 (not shown) may be extended for landing.
[0033] After takeoff, the landing gear 13 may be retracted, and the landing gear door system 20 may move from the open position 104 to the closed position 100. Figure 4H shows the start of this sequence, in which actuator 80 again biases the fourth joint J4 downward, causing the first joint J1 and the second joint J2 to move upward, as well as the third joint J3 (and door 22) to rotate clockwise around the pivot pin 44. Figure 4I shows further downward biasing by actuator 80, which causes the third joint J3 (and door 22) to continue rotating clockwise. (Note that the arrangement of elements in Figure 4I is somewhat similar to the arrangement shown earlier in Figure 4D.) Next, in Figure 4J, actuator 80 stops biasing the fourth joint J4 downward and begins biasing the fourth joint J4 upward (as indicated by the upward arrow). In Figure 4K, the actuator 80 continues to bias the fourth joint J4 upward until the third joint J3 moves clockwise enough to move the door 22 to the closed position 100, at which point the actuator 80 stops biasing the fourth joint J4 upward, as shown in Figure 4L. Note that if the actuator 80 is not biasing the fourth joint J4 upward or downward (as in Figures 4A, 4G, and 4L), the drive unit 83 acts to "lock" the contact unit 81 in its current position, and thus can keep the door 22 open (as in Figure 4G) or closed (as in Figures 4A and 4L).
[0034] According to another embodiment, the nose landing gear door system 20 for the nose landing gear compartment 12 includes a door 22 pivotable about a pivot pin 44 configured to be positioned longitudinally 21 on the aircraft body 10, the door 22 having a door panel 24 rigidly connected to an arm 30 such that the door panel 24 and the arm 30 substantially form a V shape 40 when viewed longitudinally 21, and a mechanism 50 for rotating the door 22 about the pivot pin 44 between a closed position 100 in which the outer surface 27 of the door panel 24 provides aerodynamic continuity 102 with the outer aircraft skin 11 of the aircraft body 10 and an open position 104 in which the door 22 is rotated into the nose landing gear compartment 12 and an opening 106 is exposed. The mechanism 50 is a connecting member 52 having opposing first connecting member end 54 and second connecting member end 56, in which case the first connecting member end 54 is pivotably connected to the arm 30, and a connecting device 60 having opposing first connecting device end 62 and second connecting device end 64, in which case the first connecting device end 62 is pivotably connected to the second connecting member end 56, and opposing first lever end 72 and second lever end 74, and the first lever end 72 and second lever A lever 70 having a fulcrum 76 between a bar end 74 and a first lever end 72, wherein the first lever end 72 is pivotably connected to a second coupling device end 64, and the fulcrum 76 is configured to be rotatably connected to a first mounting point 16 in the nose landing gear compartment 12; and an actuator 80 rotatably connected to the second lever end 74 and configured to selectively bias the second lever end 74 in a first direction 82 toward the opening 106 and a second direction 84 toward the opening 106.
[0035] The connecting member 52, the connecting device 60, and at least one of the parts of the lever 70 between the pivot point 76 and the second lever end 74 have a length L 52 , L 60 , L 78The struts may be configured to extend and retract. The nose landing gear door system 20 may further include struts 90, 91 having opposing first strut ends 92 and second strut ends 94, 96, in which case the first strut end 92 is pivotably connected to a first coupling end 62 and a second connecting member end 56, and the second strut ends 94, 96 are pivotably connected to either (i) a second mounting point 18 in the nose landing gear compartment 12 and (ii) the outer aircraft skin 11. The struts 90, 91 have a length L 90 , L 91 The system may include a column extender 98 configured to selectively bias the columns 90, 91 so that they extend or retract, or to allow the columns to extend or retract in length. The first lever end 72 and the second coupling end 64 may define a first joint J1 between them, the first coupling end 62 and the second connecting member end 56 may define a second joint J2 between them, and the first connecting member end 54 and the arm 30 may define a third joint J3 between them, in which case the third joint J3 is positioned substantially outside the straight line 110 when the first joint J1, the second joint J2 and the pivot pin 44 are positioned substantially along the straight line 110.
[0036] In yet another embodiment, a nose landing gear door system 20 for an aircraft 15 includes (a) an airframe 10 having a nose landing gear compartment 12 enclosed by an outer aircraft skin 11; (b) a door 22 pivotable about a pivot pin 44 positioned longitudinally 21 on the airframe 10, the door having a door panel 24 rigidly connected to an arm 30 such that the door panel 24 and the arm 30 substantially form a V shape 40 when viewed longitudinally 21; and (c) a mechanism 50 for rotating the door 22 about the pivot pin 44 between a closed position 100 in which the outer surface 27 of the door panel 24 provides aerodynamic continuity 102 with the outer aircraft skin 11 of the airframe 10 and an open position 104 in which the door 22 is rotated into the nose landing gear compartment 12 and an opening 106 is exposed. In this embodiment, the mechanism 50 comprises (i) a connecting member 52 having opposing first connecting member end 54 and second connecting member end 56, in which case the first connecting member end 54 is pivotably connected to the arm 30, and (ii) a connecting device 60 having opposing first connecting device end 62 and second connecting device end 64, in which case the first connecting device end 62 is pivotably connected to the second connecting member end 56, and (iii) opposing first lever end 72 and second lever end 74, and the first lever - A lever 70 having an end 72 and a pivot point 76 between a first lever end 72 and a second lever end 74, wherein the first lever end 72 is pivotably connected to a second coupling end 64 and the pivot point 76 is rotatably connected to a first mounting point 16 in the nose landing gear compartment 12; and (iv) an actuator 80 rotatably connected to the second lever end 74 and configured to selectively bias the second lever end 74 in a first direction 82 toward the opening 106 and a second direction 84 toward the opening 106.
[0037] In this embodiment, the nose landing gear door system 20 may further include struts 90, 91 having opposing first strut ends 92 and second strut ends 94, 96, in which case the first strut end 92 is pivotably connected to a first coupling device end 62 and a second connecting member end 56, and the second strut ends 94, 96 are pivotably connected to either a second mounting point 18 in the nose landing gear compartment 12 or the outer aircraft skin 11. In this embodiment, the first lever end 72 and the second coupling device end 64 may define a first joint J1 between them, the first coupling device end 62 and the second connecting member end 56 may define a second joint J2 between them, and the first connecting member end 54 and the arm 30 may define a third joint J3 between them, in which case the first joint J1, the second joint J2 and the pivot pin 44 are arranged substantially along a straight line 110, while the third joint J3 is arranged substantially outside the straight line 110.
[0038] It should be noted that in some configurations of the landing gear door system 20, the orientation and / or positioning of the coupling device 60 and lever 70 (and possibly the support struts 90, 91 as well) may be approximately the same in the closed position 100 and the open position 104, as can be seen by comparing Figures 4A-4B and 4K-4L (showing the closed position 100) with Figures 4F-4G (showing the open position 104).
[0039] The above description is intended to be illustrative and not limiting. The dimensions and types of materials described herein are intended to be illustrative but are not limiting and represent only example embodiments. In the following claims, the use of terms such as “first,” “second,” “upper,” and “lower” is used merely as labels and is not intended to impose numerical or positional requirements on those objects. Where used herein, an element or step described in the singular and preceded by the word “a” or “an” should be understood as not having any plural exclusion of such element or step unless such exclusion is explicitly stated. Furthermore, the phrases “at least one of A and B” and “A and / or B” should be understood to mean “A only,” “B only,” or “both A and B,” respectively. Furthermore, unless otherwise expressly stated, an embodiment “comprising” or “having” one or more elements having a particular property may include additional such elements that do not have that property. Furthermore, when broad descriptive adverbs such as "substantially" and "generally" are used herein to modify adjectives, these adverbs mean "mostly," "to a significant extent," and / or "to a large degree," and not necessarily "perfectly," "completely," "strictly," or "entirely." In addition, the term "proximate" may be used herein to describe the position of an object or part of an object relative to another object or part of it, and / or to describe the positional relationship between two objects or parts of each of them relative to each other, and may mean "near," "adjacent," "close to," "close by," or "at." Clause 1. One aspect of the present disclosure provides a landing gear door system for a landing gear compartment, comprising: a door pivotable about a pivot pin configured to be longitudinally positioned on an aircraft, the door having a door panel rigidly connected to an arm such that the door panel and arm substantially form a V shape when viewed longitudinally; and a mechanism for rotating the door about the pivot pin between a closed position configured such that the outer surface of the door panel provides aerodynamic continuity with the outer aircraft skin of the aircraft, and an open position in which the door is rotated into the landing gear compartment and an opening is exposed. Clause 2. The landing gear door system as described in Clause 1, wherein the door panel and arm are rigidly connected to each other at the apex of the door, and the pivot pin extends through the apex. Clause 3. The landing gear door system as described in Clause 1, wherein the pivot pin is configured to be rotatably connected to one of the mounting structures in the outer aircraft skin and the landing gear compartment. Clause 4. The mechanism is a landing gear door system as described in Clause 1, configured to be installed inside the landing gear compartment. Clause 5. The landing gear door system according to Clause 1, wherein the door panel has an arched contour when viewed longitudinally, so as to provide aerodynamic continuity with the outer aircraft skin when in the closed position. Clause 6. The landing gear door system as described in Clause 1, wherein the arm has a curved or bent contour when viewed in the longitudinal direction, and the curved or bent contour has a vertex that extends away from the door panel. Clause 7. The landing gear door system according to Clause 1, comprising: a connecting member having opposing first connecting member end and second connecting member end, the first connecting member end being pivotably connected to an arm; a connecting device having opposing first coupling device end and second coupling device end, the first coupling device end being pivotably connected to a second connecting member end; a lever having opposing first lever end and second lever end and a fulcrum between the first lever end and the second lever end, the first lever end being pivotably connected to the second coupling device end, the fulcrum being configured to be rotatably connected to a first mounting point in the landing gear compartment; and an actuator being rotatably connected to the second lever end and configured to selectively bias the second lever end in a first direction toward the opening and a second direction toward the opening. Clause 8. The landing gear door system according to Clause 7, wherein at least one of the connecting member, coupling device, and lever portion between the pivot point and the second lever end is configured to extend or retract in length. Clause 9. The landing gear door system according to Clause 7, further comprising a strut having opposing first strut end and second strut end, wherein the first strut end is pivotably connected to a first coupling device end and a second connecting member end, and the second strut end is pivotably connected to one of a second mounting point in the landing gear compartment and an outer aircraft skin. Clause 10. The landing gear door system as described in Clause 9, wherein the support column is configured to be retractable in length. Clause 11. The landing gear door system according to Clause 10, comprising a strut, which includes a strut extender configured to selectively bias the strut so that its length is adjustable, or to allow the strut to be adjustable in length. Clause 12. The landing gear door system according to Clause 7, wherein the first lever end and the second coupling end define a first joint between them, the first coupling end and the second connecting member end define a second joint between them, the first connecting member end and the arm define a third joint between them, and when the first joint, the second joint and the pivot pin are arranged substantially along a straight line, the third joint is arranged substantially outside the straight line. Clause 13. A door pivotable about a pivot pin configured to be longitudinally positioned on an aircraft, having a door panel rigidly connected to an arm such that the door panel and arm substantially form a V shape when viewed longitudinally, and a mechanism for rotating the door about a pivot pin between a closed position, where the outer surface of the door panel is configured to provide aerodynamic continuity with the outer aircraft skin of the aircraft, and an open position, where the door is rotated into the nose landing gear compartment and an opening is exposed, comprising a connecting member having opposing first connecting member ends and second connecting member ends, the first connecting member end being pivotably connected to an arm, and opposing first coupling device ends and A nose landing gear door system for a nose landing gear compartment is provided, comprising: a coupling device having a second coupling device end, the first coupling device end being pivotably connected to a second connecting member end; a lever having opposing first lever end and second lever end and a fulcrum between the first lever end and the second lever end, the first lever end being pivotably connected to the second coupling device end, and the fulcrum being configured to be rotatably connected to a first mounting point in the nose landing gear compartment; and a mechanism comprising an actuator rotatably connected to the second lever end and configured to selectively bias the second lever end in a first direction toward the opening and a second direction toward the opening. Clause 14. The nose landing gear door system according to Clause 13, wherein at least one of the connecting member, coupling device, and lever portion between the pivot point and the second lever end is configured to extend or retract in length. Clause 15. The nose landing gear door system according to Clause 13, further comprising a strut having opposing first strut end and second strut end, wherein the first strut end is pivotably connected to a first coupling device end and a second connecting member end, and the second strut end is pivotably connected to one of a second mounting point in the nose landing gear compartment and an outer aircraft skin. Clause 16. The nose landing gear door system according to Clause 15, wherein the strut includes a strut extender configured to selectively bias the strut so that its length is adjustable or to allow the strut to be adjustable in length. Clause 17. The nose landing gear door system according to Clause 13, wherein the first lever end and the second coupling end define a first joint between them, the first coupling end and the second connecting member end define a second joint between them, the first connecting member end and the arm define a third joint between them, and when the first joint, the second joint and the pivot pin are arranged substantially along a straight line, the third joint is arranged substantially outside the straight line. Clause 18. In another aspect of the present disclosure, an aircraft having a nose landing gear compartment enclosed by an outer aircraft skin; a door pivotable about a longitudinally positioned pivot pin on the aircraft, the door having a door panel rigidly connected to an arm such that the door panel and arm form a substantially V shape when viewed longitudinally; a mechanism for rotating the door about a pivot pin between a closed position, configured such that the outer surface of the door panel provides aerodynamic continuity with the outer aircraft skin of the aircraft, and an open position, the door being rotated into the nose landing gear compartment and an opening being exposed, the mechanism having a connecting member having opposing first connecting member ends and second connecting member ends, the first connecting member end being pivotably connected to an arm A nose landing gear door system for an aircraft is provided, comprising: a connecting member; a connecting device having opposing first connecting device end and second connecting device end, the first connecting device end being pivotably connected to a second connecting member end; a lever having opposing first lever end and second lever end, and a fulcrum between the first lever end and the second lever end, the first lever end being pivotably connected to the second connecting device end, and the fulcrum being rotatably connected to a first mounting point in the nose landing gear compartment; and an actuator rotatably connected to the second lever end and configured to selectively bias the second lever end in a first direction toward the opening and a second direction toward the opening. Clause 19. The nose landing gear door system according to Clause 18, further comprising a strut having opposing first strut end and second strut end, wherein the first strut end is pivotably connected to a first coupling device end and a second connecting member end, and the second strut end is pivotably connected to one of a second mounting point in the nose landing gear compartment and an outer aircraft skin. Clause 20. The nose landing gear door system according to Clause 18, wherein the first lever end and the second coupling end define a first joint between them, the first coupling end and the second connecting member end define a second joint between them, the first connecting member end and the arm define a third joint between them, and when the first joint, the second joint and the pivot pin are arranged substantially along a straight line, the third joint is arranged substantially outside the straight line.
[0040] This written description uses examples, including best modes, to enable a person skilled in the art to fabricate and use devices, systems, and material compositions, and to perform methods in accordance with this disclosure. The following claims, including equivalents, define the scope of this disclosure. [Explanation of symbols]
[0041] 10 aircraft 11 Outer aircraft skin 12 Landing gear compartment 13 Landing gear 14. Mounting structure 15 Aircraft 16. First mounting point 18. Second mounting point 19 Alternative second mounting point 20. Landing gear door system 21 Vertical 22 doors 23 Horizontal 24 Door Panels 25 First edge 26 Second edge 27 Exterior 28. Arch-shaped outline 29 Vertical 30 Arms 32 First arm end 34 Second arm end 36. Curved or bent contours 38 vertices 40 V-shaped 42 Vertex part 44 pivot pins 46 Vertical axis 50 mechanism 52 Connecting Member 54 End of first connecting member 56 End of second connecting member 58 Telescopic part 60 Coupling device 62 First coupling device end 64 Second coupling device end 68 Telescopic part 70 Lever 72 First lever end 74 Second lever end 76 Fulcrum 78 Telescopic part 80 Actuators 81 Contact part 82 First direction 83 Drive unit 84. Second Direction 86 In-flight direction 88 Outward direction 90 pillars 91 Pillar 92 First support end 94 Second support end 96 Second support end 98 Column extender, telescopic section 100 closed position 102 Aerodynamic continuity 104 Open position 106 Opening 108 Intermediate position 110 straight line 112 Arrow L 52 Connecting member length L 60 Coupling device length L 78 Lever portion length L 90 Support column length L 91 Support column length J1 fitting J2 joint J3 fitting J4 fitting
Claims
1. A landing gear door system for a landing gear compartment, A door that is pivotable around a pivot pin arranged vertically on the aircraft body, the door panel having an arm rigidly connected to the arm such that the door panel and arm form a substantially V shape when viewed in the vertical direction, A mechanism for rotating the door around a pivot pin between a closed position in which the outer surface of the door panel is configured to provide aerodynamic continuity with the outer aircraft skin of the aircraft, and an open position in which the door is rotated into the landing gear compartment and the opening is exposed. Equipped with, A landing gear door system in which the door panel and the arm are rigidly connected to each other at the apex of the door, and the pivot pin extends through the apex.
2. The landing gear door system according to claim 1, wherein the pivot pin is configured to be rotatably connected to one of the outer aircraft skin and the mounting structure within the landing gear compartment.
3. The landing gear door system according to claim 1, wherein the mechanism is configured to be installed inside the landing gear compartment.
4. The landing gear door system according to claim 1, wherein the door panel has a curved contour in the longitudinal direction so as to provide the aerodynamic continuity with the outer aircraft skin in the closed position.
5. The landing gear door system according to claim 1, wherein the arm has a curved or bent contour when viewed in the longitudinal direction, and the curved or bent contour has a vertex that extends away from the door panel.
6. The aforementioned mechanism is A connecting member having opposing first connecting member end and second connecting member end, wherein the first connecting member end is pivotably connected to the arm, and A coupling device having opposing first coupling device end and second coupling device end, wherein the first coupling device end is pivotably connected to the second connecting member end, A lever having opposing first lever end and second lever end, and a pivot point between the first lever end and the second lever end, wherein the first lever end is pivotably connected to the second coupling device end, and the pivot point is configured to be rotatably connected to a first mounting point in the landing gear compartment, An actuator rotatably connected to the second lever end and configured to selectively bias the second lever end in a first direction toward the opening and a second direction toward the opening, A landing gear door system according to claim 1, comprising:
7. The landing gear door system according to claim 6, wherein at least one of the connecting member, the coupling device, and the portion of the lever between the pivot point and the second lever end is configured to extend or retract in length.
8. The landing gear door system according to claim 6, further comprising a column having opposing first and second column ends, wherein the first column end is pivotably connected to a first coupling device end and a second connecting member end, and the second column end is pivotably connected to one of a second mounting point in the landing gear compartment and the outer aircraft skin.
9. The landing gear door system according to claim 8, wherein the support column is configured to be extendable or retractable in length.
10. The landing gear door system according to claim 9, wherein the strut includes a strut extender configured to selectively bias the strut so that its length can be extended or retracted, or to allow the strut to extend or retract its length.
11. The landing gear door system according to claim 6, wherein the first lever end and the second coupling device end define a first joint between them, the first coupling device end and the second connecting member end define a second joint between them, the first connecting member end and the arm define a third joint between them, and when the first joint, the second joint and the pivot pin are arranged along a substantially straight line, the third joint is arranged outside the substantially straight line.
12. A nose landing gear door system for a nose landing gear compartment, A door that is pivotable around a pivot pin arranged vertically on the aircraft body, and having a door panel rigidly connected to an arm such that the door panel and the arm form a substantially V shape when viewed vertically, A mechanism for rotating the door around a pivot pin between a closed position, in which the outer surface of the door panel is configured to provide aerodynamic continuity with the outer aircraft skin of the aircraft, and an open position, in which the door is rotated into the nose landing gear compartment and the opening is exposed, A connecting member having opposing first connecting member end and second connecting member end, wherein the first connecting member end is pivotably connected to the arm, and A coupling device having opposing first coupling device end and second coupling device end, wherein the first coupling device end is pivotably connected to the second connecting member end, A lever having opposing first lever ends and second lever ends, and a pivot point between the first lever ends and the second lever ends, wherein the first lever end is pivotably connected to the second coupling device end, and the pivot point is rotatably connected to a first mounting point in the nose landing gear compartment, A mechanism comprising an actuator rotatably connected to the second lever end, which selectively biases the second lever end in a first direction toward the opening and a second direction toward the opening. Equipped with, A nose landing gear door system in which the door panel and the arm are rigidly connected to each other at the apex of the door, and the pivot pin extends through the apex.
13. The nose landing gear door system according to claim 12, wherein at least one of the connecting member, the coupling device, and the portion of the lever between the pivot point and the second lever end is configured to extend or retract in length.
14. The nose landing gear door system according to claim 12, further comprising a column having opposing first and second column ends, wherein the first column end is pivotably connected to a first coupling device end and a second connecting member end, and the second column end is pivotably connected to one of a second mounting point in the nose landing gear compartment and the outer aircraft skin.