Rotary-wing aircraft

Abstract

This invention provides a technology that allows the main rotor and shaft to be tilted relative to the landing plane in a rotary-wing aircraft using a simple configuration. [Solution] The rotary-wing aircraft comprises a fuselage having a base located at the bottom, a shaft connected to the fuselage so as to rotate around a rotation axis that is inclined at a predetermined first angle with respect to the base, a main rotor connected to the shaft, and a landing gear that contacts the object to be landed on when the rotary-wing aircraft lands. The landing gear includes a pair of skid tubes that define a landing plane, and a pair of cross tubes connecting the pair of skid tubes, each having a first portion extending along the landing plane and a pair of second portions connecting the first portion and the pair of skid tubes. The base is inclined at a predetermined second angle with respect to the first portion and connected directly or indirectly to the first portion so as to the rotation axis inclined with respect to the landing plane.

Description

Technical Field

[0001] The present disclosure relates to a rotary-wing aircraft.

Background Art

[0002] A single-rotor type rotary-wing aircraft equipped with a tail rotor is known. For example, Patent Document 1 discloses a helicopter having a fuselage configured to tilt at a predetermined angle with respect to a landing plane on which the helicopter lands. In a state where this rotary-wing aircraft is stopped on the landing plane, the shaft connecting the fuselage and the main rotor is tilted at a predetermined angle with respect to the landing plane.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

[0007] [Figure 1] An explanatory diagram showing the schematic configuration of a helicopter according to the first embodiment of this disclosure. [Figure 2] An explanatory diagram showing the external configuration of the skid and base. [Figure 3] An explanatory diagram showing the configuration of the base's bottom surface. [Figure 4] An explanatory diagram showing the connection structure between the skid and the base. [Figure 5] An exploded perspective view showing the configuration of the coupling mechanism. [Figure 6] A cross-sectional view of the VI-VI position shown in Figure 4. [Figure 7] A cross-sectional view of the VII-VII position shown in Figure 4. [Figure 8] A schematic diagram illustrating variations of the base. [Figure 9] A schematic diagram illustrating the connection structure between the skid and the base of a helicopter according to a second embodiment of this disclosure. [Figure 10] A schematic diagram illustrating a modified example of a cross tube. [Figure 11]A schematic diagram illustrating a second modified example of the cross tube. [Figure 12] A schematic diagram illustrating a third modified example of the cross tube. [Figure 13] The configuration of the coupling mechanism of the helicopter according to the third embodiment of this disclosure will be described. [Figure 14] A schematic diagram illustrating a coupling mechanism as a modified example of a coupling mechanism. [Figure 15] A schematic diagram illustrating the connection structure between the skid and the base of a helicopter according to another embodiment. [Figure 16] A second explanatory diagram schematically shows the connection structure between the skid and the base of a helicopter according to another embodiment. [Modes for carrying out the invention]

[0008] A. First Embodiment: Figure 1 is an explanatory diagram showing the schematic configuration of a helicopter 10 according to the first embodiment of the present disclosure. The helicopter 10 is an example of a rotary-wing aircraft. As shown in Figure 1, the helicopter 10 according to this embodiment comprises a fuselage 30, a shaft 16, a main rotor 12, a tail rotor 14, and skids 50. The helicopter 10 is a single-rotor type having one main rotor 12. The tail rotor 14 counteracts the torque from the main rotor 12. The helicopter 10 may be a manned rotary-wing aircraft or an unmanned rotary-wing aircraft.

[0009] The aircraft 30 has an elongated external shape along one direction. Although not shown in the illustration, the aircraft 30 is equipped with, for example, an engine, a main transmission, a tail drive shaft, a tail transmission, and the like. The aircraft 30 includes a fuselage 31 and a tail section 32 extending from the fuselage 31. A base 40 is provided at the lowest part of the fuselage 31. A tail rotor 14 is provided at the tip of the tail section 32.

[0010] In this specification, for the sake of convenience of explanation, with respect to the direction of the helicopter 10, when the helicopter 10 lands on a horizontal plane, the longitudinal direction of the airframe 30 is defined as the front - rear direction of the helicopter 10. Among the front - rear direction, the side where the fuselage 31 of the airframe 30 is arranged is defined as the front side, and the side where the tail section 32 is arranged is defined as the rear side. Among the directions orthogonal to the front - rear direction, the side where the main rotor 12 is arranged is defined as the upper side, and the direction where the skid 50 is arranged is defined as the lower side, and this direction is defined as the up - down direction. Also, the direction orthogonal to the front - rear direction and the up - down direction is defined as the left - right direction. At this time, the front - rear direction and the left - right direction are parallel to the horizontal plane on which the helicopter 10 lands.

[0011] The shaft 16 is connected to the airframe 30 so as to rotate about the rotation axis AX. More specifically, one end of the shaft 16 is connected to the main transmission within the airframe 30. The main rotor 12 includes a plurality of blades 18, and the plurality of blades 18 are connected to the hub 17. That is, the other end of the shaft 16 is connected to the main rotor 12 via the hub 17. The power from the engine is transmitted to the main transmission, and then from the main transmission to the main rotor 12 via the shaft 16. The power from the engine is transmitted to the tail rotor 14 via the tail drive shaft and the tail transmission.

[0012] The skid 50 is a so - called skid - type landing device used when the helicopter 10 lands. The skid 50 is an example of a landing device. The skid 50 is connected to the base 40 as will be described later. The skid 50 includes a pair of skid tubes 54 and a pair of cross tubes 52.

[0013] FIG. 2 is an explanatory diagram showing the external configuration of the skid 50 and the base 40. As shown in FIG. 2, the skid tube 54 includes a tubular member extending substantially linearly. The pair of skid tubes 54 are arranged spaced apart from each other in the left-right direction. The pair of skid tubes 54 contact the landing target when the helicopter 10 lands on the landing target. The landing target is, for example, the ground or a helicopter landing pad on a ship. The portion where the pair of skid tubes 54 contact the landing target defines the landing plane LS. The landing plane LS is a virtual plane that defines the attitude of the helicopter 10 landed on the landing target and the directions of each part of the helicopter 10. In the present embodiment, the landing plane LS is parallel to the front-rear direction and the left-right direction.

[0014] The pair of cross tubes 52 includes tubular members that connect the pair of skid tubes 54. The pair of cross tubes 52 are arranged spaced apart from each other in the front-rear direction. One end of the cross tube 52 is connected to one skid tube 54, and the other end is connected to the other skid tube 54. The cross tube 52 absorbs the energy generated by the grounding of the skid tube 54 when the helicopter 10 lands and alleviates the impact on the airframe 30. The pair of cross tubes 52 includes a first portion 521 and a second portion 522. Hereinafter, although the description is made when the shapes of the pair of front and rear cross tubes 52 are substantially the same shape, the shape of the cross tube 52 is not limited to this example. For example, in each of the cross tubes 52 arranged front and rear, the detailed shapes and dimensions may be different from each other.

[0015] The first part 521 is indirectly connected to the base 40 via a connecting mechanism 90. When no load is applied to the first part 521, it extends in a direction parallel to the landing plane LS. In this embodiment, the first part 521 extends along the left-right direction. The pair of first parts 521 are arranged parallel to each other and spaced apart. The first part 521 may be curved when loads such as those applied during landing are applied. The loads applied to the first part 521 refer to various loads, such as the flight load of the helicopter 10 and the weight of the first part 521 itself when the helicopter 10 is landed. When no load is applied to the first part 521, it refers to a situation where none of the aforementioned loads are applied to the first part 521. In the following description, assuming the definition of the load applied to the first part 521 described above, the case when no load is applied to each component of the helicopter 10 will be used as an example.

[0016] In this embodiment, the pair of first portions 521 define a virtual plane that is substantially parallel to the accretion plane LS when no load is applied. This virtual plane, which is substantially parallel to the accretion plane LS when no load is applied, will hereinafter also be referred to as the skid top surface. The skid top surface is substantially parallel to the extending direction of the first portions 521.

[0017] The second section 522 connects the first section 521 to a pair of skid tubes 54. The second section 522 has a curved shape and is formed, for example, by bending a circular tube.

[0018] The base 40 is fixed to the lowest part of the fuselage 31 of the aircraft body 30 by connectors or the like. The base 40 is made of a metal such as an aluminum alloy. As shown in Figure 2, the skid 50 is connected to the base 40. The base 40 includes a pair of supports, including a front support 41 and a rear support 42, a beam member 43, and a plate 44. The base 40 may be made of a resin material such as FRP (Fiber Reinforced Plastics) instead of metal, or it may include both metal and resin materials.

[0019] The plate 44 is a sheet-like member that defines the upper surface of the base 40. For example, devices housed in the body 31 are placed on the plate 44.

[0020] Figure 3 is an explanatory diagram showing the configuration of the bottom surface 40B of the base 40. The front support 41 is connected to the front cross tube 52 of a pair of cross tubes 52. More specifically, the front support 41 is connected to the first portion 521 of the front cross tube 52. The front support 41 is provided along the extending direction of the first portion 521 of the front cross tube 52. As shown in Figure 2, a right-side projection 412 is formed near the right-side end of the front support 41, projecting toward the first portion 521 from the front support 41. A left-side projection 414 is formed near the left-side end of the front support 41, projecting toward the first portion 521 from the front support 41.

[0021] As shown in Figure 3, the rear support 42 is connected to the rear cross tube 52 of a pair of cross tubes 52. More specifically, the rear support 42 is connected to the first portion 521 of the rear cross tube 52. The rear support 42 is provided along the extending direction of the first portion 521 of the rear cross tube 52. In this embodiment, the bottom surface of the front support 41 and the bottom surface of the rear support 42 are substantially on the same plane. The rear support 42 has a right-side projection 422 and a left-side projection 424, which are configured similarly to the right-side projection 412 and left-side projection 414 described above. The detailed configuration of the rear support 42 is the same as that of the front support 41, so a detailed explanation is omitted.

[0022] The beam member 43 connects the front support 41, the rear support 42, and the plate 44. The rear support 42 and the front support 41 are connected by the beam member 43 so that their extending directions are substantially parallel. In this embodiment, the front support 41 and the rear support 42 are subjected to so-called weight reduction processes such as hollowing out or thinning. By connecting the lightweight front support 41 and the rear support 42 with the beam member 43, the base 40 can be made lighter compared to the case where the front support 41, the rear support 42, and the beam member 43 are formed as a single unit. However, this is not limited to this, and the front support 41, the rear support 42, the beam member 43, and the plate 44 may be composed of, for example, a single rectangular member.

[0023] As shown in Figure 2, in this embodiment, the base 40 further comprises two front auxiliary supports 410 and two rear auxiliary supports 420. The front auxiliary supports 410 are used to connect the connecting mechanism 90 to the right projection 412 and to connect the connecting mechanism 90 to the left projection 414. The rear auxiliary supports 420 are used to connect the connecting mechanism 90 to the right projection 422 and to connect the connecting mechanism 90 to the left projection 424. The detailed configurations of the front auxiliary supports 410 and the rear auxiliary supports 420 will be described later.

[0024] Figure 4 is an explanatory diagram showing the connection structure between the skid 50 and the base 40. Figure 4 shows the skid 50 and the base 40 in a front view from the front.

[0025] Figure 4 shows the first angle A1 between the bottom surface 40B of the base 40 and the axis of rotation AX. The bottom surface 40B of the base 40 refers to the lower surface of the base 40 defined by the portion of the lower end of the base 40 excluding the right-side projection 412, the left-side projection 414, the right-side projection 422, and the left-side projection 424. In this embodiment, the bottom surface 40B of the base 40 is a virtual plane P1 defined by the bottom surface of the front support 41 and the bottom surface of the rear support 42. The bottom surface 40B does not have to be a plane; it may be a curved surface. Alternatively, recesses or protrusions may be formed on the bottom surface 40B.

[0026] As shown in Figure 4, in this embodiment, the axis of rotation AX is configured to be perpendicular to the bottom surface 40B of the base 40. That is, the first angle A1 is approximately 90 degrees. However, the axis of rotation AX is not limited to being perpendicular to the bottom surface 40B of the base 40, but may also be tilted by a predetermined angle to the left or right from the perpendicular position to the bottom surface 40B, for example, 75 degrees, 80 degrees, or 85 degrees.

[0027] As shown in Figure 4, in this embodiment, the base 40 is connected to the first portion 521 of the cross tube 52 via a right projection 412 and a left projection 414. The right projection 412 has a bottom surface 412B, and the left projection 414 has a bottom surface 414B. Bottom surface 412B is an example of the tip surface of the right projection 412. Bottom surface 414B is an example of the tip surface of the left projection 414.

[0028] The bottom surface 412B faces the first portion 521 of the front cross tube 52 and is connected to the first portion 521. The bottom surface 414B faces the first portion 521 of the front and is connected to the first portion 521. Similarly, in the rear support 42 shown in Figure 3, the bottom surface 422B of the right projection 422 and the bottom surface 424B of the left projection 424 face the first portion 521 of the rear cross tube 52 and are connected to the first portion 521. Bottom surfaces 422B and 424B are examples of the tip surfaces of the right projection 422 and the left projection 424. Thus, bottom surfaces 412B, 414B, 422B, and 424B are located on substantially the same plane and are connecting portions that connect the pair of first portions 521 and the base 40.

[0029] As shown in Figure 4, the distance from the bottom surface 40B of the base 40 to the bottom surface 412B of the right projection 412 is different from the distance from the bottom surface 40B of the base 40 to the bottom surface 414B of the left projection 414. In other words, the right projection 412 and the left projection 414 are at different heights from the virtual plane P1. In the example in Figure 4, the height of the right projection 412 is higher than the height of the left projection 414. The same applies to the right projection 422 and the left projection 424. Due to the height difference between the right projection 412 and the left projection 414, the bottom surface 40B of the base 40, i.e., the virtual plane P1, is inclined with respect to the skid top surface P2.

[0030] In this embodiment, the virtual plane P1 is inclined with respect to the skid top surface P2 at a predetermined second angle A2. Therefore, with respect to the landing plane LS, the rotation axis AX is inclined to the left by a second angle A2 with respect to the vertical. In a helicopter 10 that has landed on a horizontal plane, the rotation axis AX is inclined by a second angle A2 with respect to the vertical.

[0031] The second angle A2 is set considering a balance between obtaining sufficient thrust from the main rotor 12 for the helicopter 10 to take off and suppressing the lateral force caused by the tail rotor 14 immediately after takeoff. In this embodiment, the second angle A2 is set to approximately 2 degrees. With this configuration, sufficient thrust from the main rotor 12 can be obtained, while immediately after takeoff, the thrust from the inclined main rotor 12 can suppress the lateral force caused by the thrust of the tail rotor 14.

[0032] The second angle A2 can be arbitrarily set by adjusting the height difference between the right protrusion 412 and the left protrusion 414. From the viewpoint of suppressing lateral force, the second angle A2 is preferably greater than 0 degrees, and more preferably 1 degree or more. In order to obtain sufficient thrust from the main rotor 12, the second angle A2 is preferably set to 5 degrees or less, and more preferably 3 degrees or less. If the second angle A2 is between 1 degree and 3 degrees, a suitable balance is achieved between the thrust from the main rotor 12 and the suppression of lateral force.

[0033] The configuration of the coupling mechanism 90 will be described with reference to Figures 5 to 7, and, as appropriate, to Figure 3. Figure 5 is an exploded perspective view showing the configuration of the coupling mechanism 90. Figure 6 is a cross-sectional view of the VI-VI position shown in Figure 4.

[0034] As shown in Figure 5, the connecting mechanism 90 connects the first portion 521 of the cross tube 52 to the base 40. By using the connecting mechanism 90, the user can connect the cross tube 52 to the base 40 without performing any special processing on the cross tube 52 for connection to the base 40. Therefore, by using the connecting mechanism 90, the user can connect an existing cross tube 52 to the base 40 without developing a specially shaped cross tube. In this case, the user can easily change the connection position between the cross tube 52 and the base 40. Therefore, even if the user changes the position of the right-side projection 412 or the left-side projection 414 of the base 40 in the left-right direction, for example, the user can easily connect the modified base 40 to the cross tube 52. As shown in Figure 5, the connecting mechanism 90 includes a connector 70, a fixing device 80, and two restricting devices 60.

[0035] The connector 70 is a metal member having a substantially U-shape. The connector 70 connects the cross tube 52 to the base 40 together with fasteners such as bolts B1 and nuts N1. The connector 70 includes a first end 71, a second end 72, and a recess 74 defined between the first end 71 and the second end 72. The first portion 521 of the cross tube 52 is positioned in the recess 74. In this embodiment, a fixing device 80 is positioned between the recess 74 and the first portion 521.

[0036] The first end 71 is positioned in front of the recess 74, and the second end 72 is positioned behind the recess 74. As shown in Figure 5, the first end 71 has a through hole 71H that extends vertically. The second end 72 has a through hole 72H that extends vertically. A bolt B1 is inserted through the through hole 71H. As shown in Figure 6, the bolt B1 inserted through the through hole 71H is then inserted through a through hole 412H formed in the bottom surface 412B of the right-side projection 412 and fastened with a nut N1. As a result, the first end 71 is connected to the right-side projection 412.

[0037] As shown in Figures 5 and 6, in this embodiment, the base 40 further includes a front auxiliary support 410. The front auxiliary support 410 is connected to the rear side of the front support 41 and the rear side of the right projection 412 by fasteners BN such as bolts. The front-to-back width of the bottom surface 412B of the right projection 412 is shorter than the distance from through hole 71H to through hole 72H in the connector 70. Therefore, the front-to-back distance of the bottom surface 412B of the right projection 412 is insufficient, and the first portion 521 cannot be connected using the connector 70. The reason why the front-to-back width of the front support 41 and the right projection 412 is set to be shorter than the distance from through hole 71H to through hole 72H in the connector 70 is to minimize the shape of the front support 41 from the viewpoint of weight reduction. In the manufacturing process of the front support 41, forming the front support 41 first and then connecting it to the separate front auxiliary support 410 results in higher production efficiency than forming the front auxiliary support 410 and the front support 41 as a single unit.

[0038] The front auxiliary support 410 is connected to the rear side of the right protrusion 412 such that the bottom surface 410B of the front auxiliary support 410 is flush with the bottom surface 412B of the right protrusion 412 and positioned behind the bottom surface 412B. In other words, the front auxiliary support 410 has the function of extending the bottom surface 412B to the rear. This makes it possible to miniaturize and lighten the front support 41 and improve the production efficiency of the front support 41.

[0039] As shown in Figure 6, the second end 72 of the connector 70 is connected to the bottom surface 410B of the front auxiliary support 410. Specifically, the bolt B1 inserted through the through hole 72H is inserted through the through hole 410H formed in the bottom surface 410B of the front auxiliary support 410 and fastened with a nut N1. In this way, the second end 72 of the connector 70 is indirectly connected to the right-side projection 412 via the front auxiliary support 410 which is connected to the rear side of the right-side projection 412. As a result, the connector 70 is fastened to the right-side projection 412 and the front auxiliary support 410 of the base 40 with the first portion 521 positioned in the recess 74.

[0040] Figure 7 is a cross-sectional view of the position VII-VII shown in Figure 4. As shown in Figure 7, the left protrusion 414 is connected to the front auxiliary support 410, similar to the right protrusion 412. Specifically, the front auxiliary support 410 is connected to the rear side of the front support 41 and the rear side of the left protrusion 414 such that the bottom surface 410B of the front auxiliary support 410 is flush with the bottom surface 414B of the left protrusion 414 and positioned behind the bottom surface 414B.

[0041] As shown in Figure 7, the bolt B1 inserted through the through hole 71H of the first end 71 is inserted through the through hole 414H formed in the bottom surface 414B of the left protrusion 414 and fastened with a nut N1. The bolt B1 inserted through the through hole 72H of the second end 72 is inserted through the through hole 410H formed in the bottom surface 410B of the front auxiliary support 410 and fastened with a nut N1. In this way, the second end 72 of the connector 70 is indirectly connected to the left protrusion 414 via the front auxiliary support 410 which is connected to the rear side of the left protrusion 414. As a result, the connector 70 is fastened to the left protrusion 414 and the front auxiliary support 410 of the base 40 with the first portion 521 positioned in the recess 74.

[0042] As shown in Figure 3, in this embodiment, two rear auxiliary supports 420 are connected to the rear support 42 of the base 40, similar to 41. The rear auxiliary supports 420 differ from the front auxiliary supports 410 in that their position relative to the support is different. The other configurations of the rear auxiliary supports 420 are generally the same as those of the front auxiliary supports 410. The two rear auxiliary supports 420 are connected to the front side of the right protrusion 422 and the front side of the left protrusion 424 on the rear support 42. Specifically, one of the rear auxiliary supports 420 is connected to the front side of the right protrusion 422 such that the bottom surface 420B of the rear auxiliary support 420 is flush with the bottom surface 422B of the right protrusion 422 and is positioned in front of the bottom surface 422B. The other rear auxiliary support 420 is connected to the front of the left protrusion 424 such that the bottom surface 420B of the rear auxiliary support 420 is flush with the bottom surface 424B of the left protrusion 424 and positioned in front of the bottom surface 424B. In other words, the rear auxiliary support 420, like the front auxiliary support 410, has the function of extending the bottom surface 422B of the right protrusion 422 and the bottom surface 424B of the left protrusion 424 toward the front.

[0043] As shown in Figure 5, in this embodiment, the coupling mechanism 90 further includes a fastener 80. The fastener 80 is positioned between the coupling 70 and the first portion 521 in a recess 74 of the coupling 70. The fastener 80 prevents or restricts the first portion 521 from rotating about a virtual axis extending in the direction of extension of the first portion 521 from the cross-sectional center of the first portion 521. The fastener 80 includes an upper body portion 81 positioned to cover the upper side of the first portion 521 and a lower body portion 82 positioned to cover the lower side of the first portion 521. The upper body portion 81 and the lower body portion 82 are fixed between the coupling 70 and the base 40 by a connection between the coupling 70 and the base 40.

[0044] The upper body portion 81 includes a first contact surface 811, a second contact surface 812, and a third contact surface 813. The lower body portion 82 includes a lower inner surface 822 and a lower outer surface 823. The upper body portion 81 and the lower body portion 82 are metal members having a substantially U-shape. The second contact surface 812 is a curved surface formed on the inner circumference of the substantially U-shape of the upper body portion 81. The lower inner surface 822 is a curved surface formed on the inner circumference of the substantially U-shape of the lower body portion 82. The second contact surface 812 and the lower inner surface 822 abut against the outer circumference of the first portion 521, suppressing or preventing the first portion 521 from rotating relative to the fixing device 80.

[0045] The third contact surface 813 is a curved surface formed on the outer circumference of the approximately U-shaped upper body portion 81, and the lower outer surface 823 is a curved surface formed on the outer circumference of the approximately U-shaped lower body portion 82. The third contact surface 813 and the lower outer surface 823 contact the recess 74 of the connector 70. In this embodiment, a wall surface 816 is formed around the third contact surface 813, and a wall surface 826 is formed around the lower outer surface 823. The third contact surface 813 and the lower outer surface 823, along with the wall surfaces 816 and 826, define recesses on the outer circumferences of the upper body portion 81 and the lower body portion 82. The first end portion 71, the second end portion 72, and the recess 74 are fitted into these recesses. As a result, the movement of the fixing device 80 in the left-right direction relative to the connector 70 is restricted by the fitting with the recesses. Therefore, the recess can suppress or prevent the first portion 521 within the fixing device 80 from moving in the left-right direction relative to the connecting device 70.

[0046] The first contact surface 811 is a plane formed at the upper end of the upper main body portion 81. As shown in Figure 6, the first contact surface 811 contacts the bottom surface 412B of the right projection portion 412 and the bottom surface 410B of the front auxiliary support 410. By bringing the first contact surface 811 into surface contact with the bottom surfaces 412B and 410B, the rotation of the fixing device 80 relative to the base 40 can be suppressed or prevented. Therefore, by using the connecting mechanism 90 including the fixing device 80, the rotation of the first portion 521 relative to the base 40 can be suppressed or prevented.

[0047] As shown in Figure 7, the connecting mechanism 90 is connected to the left protrusion 414 in the same configuration as the right protrusion 412. For example, the first contact surface 811 contacts the bottom surface 414B of the left protrusion 414 and the bottom surface 410B of the front auxiliary support 410. The connecting mechanism 90 connects the rear support 42 and the rear first portion 521 in the same configuration as the left protrusion 414. In the right protrusion 422, the first contact surface 811 contacts the bottom surfaces 422B and 420B, similar to the right protrusion 412, and in the left protrusion 424, it contacts the bottom surfaces 424B and 420B, similar to the left protrusion 414.

[0048] As shown in Figure 5, in this embodiment, the coupling mechanism 90 further includes two restrictors 60. The two restrictors 60 are positioned on either side of the fixing device 80 in the left-right direction. The restrictors 60 restrain or prevent the coupling device 70 and the fixing device 80 from moving relative to the first portion 521 along the direction of extension of the first portion 521.

[0049] The restrictor 60 comprises an upper body portion 61 positioned to cover the upper part of the first portion 521 and a lower body portion 62 positioned to cover the lower part of the first portion 521. The upper body portion 61 and the lower body portion 62 are metal members each having a substantially U-shape.

[0050] The upper body portion 61 has a first end portion 611, a second end portion 612, and a recess 614 defined between the first end portion 611 and the second end portion 612. The lower body portion 62 has a first end portion 621, a second end portion 622, and a recess 624 defined between the first end portion 621 and the second end portion 622. The first end portion 611 and the first end portion 621 are fastened together by bolts B2 and nuts N2. The second end portion 612 and the second end portion 622 are fastened together by bolts B2 and nuts N2. In other words, the upper body portion 61 and the lower body portion 62 are fastened together by bolts and nuts with the first portion 521 positioned in the recesses 614 and 624. As a result, the first portion 521 is sandwiched between the upper body portion 61 and the lower body portion 62.

[0051] The two restricting members 60 that grip the first portion 521 are positioned on both sides of the connector 70 in the left-right direction, thereby restricting the movement of the connector 70 and the fixing member 80 along the extending direction of the first portion 521. Thus, the left-right movement of the skid 50 relative to the base 40 can be suppressed or prevented.

[0052] As described above, according to the helicopter 10 of this embodiment, the base 40 is connected to the first part 521 at a predetermined second angle A2 such that the rotation axis AX of the shaft 16 is inclined with respect to the landing plane LS. Therefore, the thrust of the main rotor 12 in an inclined state with respect to the landing plane LS can be used to counteract the lateral force during takeoff of the helicopter 10. In this embodiment, the function of inclining the rotation axis AX of the shaft 16 with respect to the landing plane LS is integrated into the connection structure between the first part 521 of the cross tube 52, which is a part of the helicopter 10, and the base 40. Therefore, the effect of lateral force during takeoff of the helicopter 10 can be suppressed or prevented with a simple configuration.

[0053] According to the helicopter 10 of this embodiment, the base 40 is provided with a right-side projection 412 and a left-side projection 414 on both the right and left sides of the base 40, projecting from the base 40 at different heights. The base 40 is connected to the first portion 521 via the right-side projection 412 and the left-side projection 414, and is inclined at a second angle A2 with respect to the first portion 521. Therefore, the base 40 can be inclined with respect to the landing plane LS by a simple configuration that utilizes the height difference between the right-side projection 412 and the left-side projection 414.

[0054] According to the helicopter 10 of this embodiment, the base 40 includes a front support 41 and a rear support 42 that are connected parallel to each other. The right-side projection 412 and the left-side projection 414 are provided on the bottom surface 40B of the front support 41 and the rear support 42. By providing the support in separate front and rear sections, the weight of the base 40 can be reduced compared to the case where a single, integrated base 40 extending from the front to the rear is provided.

[0055] According to the helicopter 10 of this embodiment, the base 40 further comprises a front auxiliary support 410 connected to the front support 41 and having a bottom surface 410B, and a rear auxiliary support 420 connected to the rear support 42 and having a bottom surface 420B. The front first portion 521 is connected to the bottom surface 410B and the bottom surface 412B of the right protrusion 412, and to the bottom surface 410B and the bottom surface 414B of the left protrusion 414. The rear first portion 521 is connected to the bottom surface 420B and the bottom surface 422B of the right protrusion 422, and to the bottom surface 420B and the bottom surface 424B of the left protrusion 424. By connecting the auxiliary supports to the front support 41 and the rear support 42 and then connecting them to the first portion 521, the front support 41 and the rear support 42 can be made smaller and lighter.

[0056] In the helicopter 10 of this embodiment, the connector 70 is connected to the right-side projection 412 and the bottom surface 40B of the front auxiliary support 410 with the first portion 521 positioned in the recess 74. By using the connector 70, the skid 50 and the base 40 can be connected without performing any processing on the skid 50 for connection to the base 40. Furthermore, since the arrangement of the connecting mechanism 90 can be easily changed, the user can easily change the connection position between the base 40 and the first portion 521.

[0057] The helicopter 10 of this embodiment includes a fixing device 80 having a first contact surface 811 that abuts against the bottom surface 412B of the right-side projection 412, and a second contact surface 812 and a lower inner surface 822 that abut against the outer circumference of the first portion 521. By bringing the first contact surface 811 into surface contact with the bottom surface 412B, the fixing device 80 can be prevented from rotating relative to the base 40. Therefore, by using a connecting mechanism 90 including the fixing device 80, the first portion 521 can be prevented from rotating relative to the base 40.

[0058] A2. Variant: Figure 8 is a schematic explanatory diagram showing a modified example of the base 40. In the first embodiment described above, an example was shown in which the front support 41 of the base 40 has both a right-side projection 412 and a left-side projection 414. In contrast, the front support 41 may be configured to have only either the right-side projection 412 or the left-side projection 414. In this case, the rear support 42 has only the projection at the position corresponding to either the right-side projection 412 or the left-side projection 414 of the two projections, the right-side projection 422 and the left-side projection 424, that are present on the front support 41. That is, if the front support 41 has only the right-side projection 412, the rear support 42 has the right-side projection 422, and if the front support 41 has only the left-side projection 414, the rear support 42 has only the left-side projection 424.

[0059] In the following explanation, the configuration of the front support and the configuration of the first front part will be used as examples, and the configuration of the rear support and the configuration of the first rear part will be omitted.

[0060] In the example shown in Figure 8, the base 40a does not have a left-side projection 414, but only a right-side projection 412. A projection that is located on only one side of the base 40a is also called a single-sided projection. In the example shown in Figure 8, the right-side projection 412 is an example of a single-sided projection.

[0061] As shown in Figure 8, a bottom surface 40B2 is formed near the left end of the front support 41 in place of the left protrusion 414. The bottom surface 40B2 is configured to be flush with the bottom surface 412B. The bottom surface 40B2, together with the bottom surface 412B, is parallel to the skid upper surface P2. The left end of the first portion 521 is connected to the bottom surface 40B2 using a connecting mechanism 90. Even with this configuration, the same effects as in the first embodiment can be obtained. Furthermore, the first portion 521 and the base 40a can be brought closer together than in the first embodiment.

[0062] B. Second Embodiment: Figure 9 is a schematic diagram illustrating the connection structure between the skid 50b and the base 40b of the helicopter 10 according to the second embodiment of this disclosure. The helicopter 10 of the second embodiment differs from the helicopter 10 of the first embodiment in that it has a base 40b instead of a base 40 and a skid 50b instead of a skid 50, but the other configurations are the same. In each of the figures from Figure 9 onward, the second angle A2 is shown as a larger angle than it actually is in order to facilitate understanding of the technology.

[0063] The configuration of the base 40b differs from that of the base 40 shown in the first embodiment in that it includes a front support 41b and a rear support configured similarly to the front support 41b. The front support 41b differs from that of the front support 41 shown in the first embodiment in that it does not include a right-side projection 412 and a left-side projection 414. That is, the bottom surface 40B of the front support 41b is configured to be approximately flush with the surface from the left to the right. The configuration of the rear support is the same as that of the front support 41b, so its description is omitted. The skid 50b is connected to the bottom surface 40B by a connecting mechanism 90.

[0064] The configuration of the skid 50b differs from that of the skid 50 shown in the first embodiment in that it includes a cross tube 52b including a first portion 521b instead of a cross tube 52 including a first portion 521. The first portion 521b further differs from the first portion 521 shown in the first embodiment in that it includes a right-side projection 526, two lower projections 527, and a left-side projection 528. The right-side projection 526, the lower projections 527, and the left-side projection 528 are formed integrally with the first portion 521b, for example. The right-side projection 526 and the left-side projection 528 are provided near the right-side end and the left-side end, respectively, of the first portion 521b. The configuration of the rear first portion is the same as that of the front first portion 521b, so its description is omitted.

[0065] As shown in Figure 9, in this embodiment, the base 40b is connected to the first portion 521b of the cross tube 52b via a right projection 526 and a left projection 528. The right projection 526 and the left projection 528 are at different heights from the skid top surface P2. In this embodiment, the height of the right projection 526 is higher than the height of the left projection 528. Due to the height difference between the right projection 526 and the left projection 528, the bottom surface 40B is inclined with respect to the skid top surface P2.

[0066] The right-side projection 526 has a tip surface 526T, and the left-side projection 528 has a tip surface 528T. The tip surfaces 526T and 528T are located on substantially the same plane. The tip surface 526T is in contact with the bottom surface 40B of the front support 41b and is connected to the bottom surface 40B, for example, using a connecting mechanism 90. Although not shown in the figures, the tip surface 526T is also fastened to the bottom surface 410B of the front auxiliary support 410.

[0067] The tip surface 528T is in contact with the bottom surface 40B of the front support 41b and is connected to the bottom surface 40B, for example, using a connecting mechanism 90. Although not shown in the figures, the tip surface 528T is also fastened to the bottom surface 410B of the front auxiliary support 410.

[0068] The two lower protrusions 527 are located below the first portion 521b, on the right and left sides of the first portion 521b, respectively. More specifically, the two lower protrusions 527 are located directly below the right protrusion 526 and directly below the left protrusion 528. The two lower protrusions 527 project downward from the first portion 521b. The configuration of the two lower protrusions 527 is substantially the same, and the distance from the first portion 521b to the tip of each lower protrusion 527 is substantially the same.

[0069] The lower projection 527 has a tip surface 527B. The two tip surfaces 527B are substantially parallel to a virtual plane P1 that passes through tip surfaces 526T and 528T, respectively. This allows the user to fasten from tip surface 527B to tip surface 526T using a set of fasteners BN such as bolts and nuts.

[0070] According to the helicopter 10 of this embodiment, the first portion 521b is provided with a right-side projection 526 and a left-side projection 528 on both the right and left sides of the upper end of the first portion 521b, projecting from the first portion 521b at different heights. The base 40b is connected to the first portion 521b in a state inclined at a predetermined second angle A2 with respect to the first portion 521b such that the axis of rotation AX is inclined with respect to the accretion plane LS. Therefore, even with a simple configuration change of providing projections on the cross tube 52b, the axis of rotation AX of the shaft 16 can be inclined with respect to the accretion plane LS, similar to the first embodiment.

[0071] B2. Variations: Figure 10 is a schematic diagram illustrating a modified example of the cross tube 52b. In the second embodiment described above, an example was shown in which lower protrusions 527 are provided on the right and left sides of the lower end of the first portion 521b. In contrast, as shown in Figure 10, a lower adapter 93 may be provided instead of the lower protrusions 527.

[0072] Skid 50b2 differs from skid 50b shown in the second embodiment in that it includes a cross tube 52b2 instead of a cross tube 52b. The configuration of the cross tube 52b2 differs from that of the cross tube 52b in that it includes a first part 521b2 that does not have a lower projection 527 instead of a first part 521b.

[0073] The lower adapter 93 is included in the coupling mechanism 90. The lower adapter 93 has substantially the same external shape and function as the lower projection 527 shown in the second embodiment, but differs from the lower projection 527 in that it is separate from the first part 521b2.

[0074] The two lower adapters 93 are provided at the lower end of the first portion 521b2, on the right and left sides of the first portion 521b2, respectively. More specifically, the two lower adapters 93 are positioned directly below the right projection 526 and directly below the left projection 528. The two lower adapters 93 are positioned to project downward from the first portion 521b. The configurations of the two lower adapters 93 are substantially the same, and the distance from the first portion 521b to the tip of each is substantially the same.

[0075] The lower adapter 93 has a tip surface 93B. The two tip surfaces 93B are substantially parallel to a virtual plane P1 that passes through the tip surfaces 526T and 528T, respectively. With this configuration, the tip surface 93B to the tip surface 526T can be fastened using a set of fasteners BN such as bolts and nuts. In this embodiment as well, the same effects as in the second embodiment can be obtained. Note that the configuration of the rear first part is the same as the configuration of the front first part 521b2, so its description is omitted.

[0076] B3. Modification 2: Figure 11 is a schematic diagram illustrating a second modified example of the cross tube 52b. In the second embodiment described above, an example was shown in which lower protrusions 527 are provided on the right and left sides of the lower end of the first portion 521b. In contrast, in this embodiment, the helicopter 10 comprises a base 40b3 and a skid 50b3. Specifically, the skid 50b3 of this embodiment differs from the skid 50b2 shown in Figure 10 in that it does not have a lower protrusion 527 at the lower end of the first portion 521b3.

[0077] Skid 50b3 differs from skid 50b shown in the second embodiment in that it includes a cross tube 52b3, which includes a first portion 521b3, instead of the cross tube 52b. The first portion 521b3 differs from the first portion 521b shown in the second embodiment in that it does not have a lower projection 527. In the front view shown in Figure 11, the lower end of the first portion 521b3 is substantially straight and substantially parallel to the direction of extension of the skid upper surface P2 and the first portion 521b3.

[0078] Base 40b3 differs from base 40b shown in the second embodiment in that it includes a front support 41b3 instead of a front support 41b. Front support 41b3 further differs from front support 41b in that it includes a bottom wall 41B which includes an angle adjustment section 417.

[0079] The bottom wall 41B is provided at the lower end of the front support 41b3. The surface of the bottom wall 41B facing the first portion 521b3 is the bottom surface 40B. The surface of the bottom wall 41B opposite the bottom surface 40B functions as an angle adjustment section 417.

[0080] The angle adjustment section 417 is a surface substantially parallel to the direction of extension of the skid upper surface P2 and the first section 521b3. With this configuration, fasteners BN for fastening from the lower end of the first section 521b3 to the angle adjustment section 417 can be easily positioned, and the front end surface 527B to the front end surface 528T can be fastened using a single set of fasteners BN such as bolts and nuts. In this embodiment as well, the same effects as in the second embodiment can be obtained. Note that the configuration of the rear support and the rear first section is the same as the configuration of the front support 41b3 and the front first section 521b3, so a description is omitted.

[0081] B4. Modification 3: Figure 12 is a schematic diagram illustrating a third modified example of the cross tube 52b. In the second embodiment described above, an example was shown in which a right-side projection 526 and a left-side projection 528 are provided on the right and left sides of the upper end of the first portion 521b. In contrast, as shown in Figure 12, a single projection 529 may be provided at the upper end of the first portion 521b. In this embodiment, the helicopter 10 includes a base 40b3 and a skid 50b4 similar to those in the second modified example described above.

[0082] Skid 50b4 differs from the skid 50b shown in the second embodiment above in that it includes a cross tube 52b4, which includes a first portion 521b4, instead of the cross tube 52b. The configuration of the first portion 521b4 differs in that it does not have a lower projection 527 and has a single projection 529 instead of the right projection 526 and the left projection 528.

[0083] The projection 529 extends from near the left end to near the right end of the first portion 521b4. The projection 529 protrudes from the first portion 521b4 toward the front support 41b3. The tip surface 529T of the projection 529 is substantially parallel to the virtual plane P1.

[0084] The base 40b3 is fastened by fasteners BN with the bottom surface 40B and the tip surface 529T of the protrusion 529 in contact. This allows the area of ​​the tip surface 529T to be larger than when two protrusions are provided, and the base 40b3 can be firmly supported. Note that the configuration of the rear support and the rear first part is the same as the configuration of the front support 41b3 and the front first part 521b414, so a description is omitted.

[0085] C. Third Embodiment: Figure 13 illustrates the configuration of the coupling mechanism 90c of the helicopter 10 according to the third embodiment of this disclosure. The helicopter 10 of the third embodiment differs from the helicopter 10 of the first embodiment in that it has a base 40b shown in the second embodiment instead of a base 40, and a coupling mechanism 90c instead of a coupling mechanism 90, but the other configurations are the same. The configuration of the rear support and the rear first part is the same as the configuration of the front support 41 and the front first part 521, so a description is omitted.

[0086] The coupling mechanism 90c comprises a right-side adapter 92, a left-side adapter 94, and a lower-side adapter 93. The base 40b is indirectly connected to the first part 521 via the right-side adapter 92 and the left-side adapter 94. The lower-side adapter 93 has the same configuration as the lower-side adapter 93 shown in Figure 10, so its description is omitted.

[0087] The right-side adapter 92 and the left-side adapter 94 are provided on the right and left sides, respectively, between the base 40b and the first portion 521. The right-side adapter 92 and the left-side adapter 94 have different heights. In this embodiment, the height of the right-side adapter 92 is greater than the height of the left-side adapter 94. Due to the height difference between the right-side adapter 92 and the left-side adapter 94, the bottom surface 40B is inclined with respect to the skid top surface P2.

[0088] The right adapter 92 has a tip surface 92T, and the left adapter 94 has a tip surface 94T. The tip surfaces 92T and 94T are substantially coplanar. A virtual plane P1 passing through the tip surfaces 92T and 94T is substantially parallel to the tip surfaces 93B of each of the two lower adapters 93. The tip surfaces 92T and 94T are in contact with the bottom surface 40B of the front support 41 and are connected to the bottom surface 40B, for example, using fasteners BN.

[0089] According to the helicopter 10 of this embodiment, a right-side adapter 92 and a left-side adapter 94 are provided on both the right and left sides between the base 40b and the first part 521, and are of different heights. The base 40b is connected to the first part 521 via the right-side adapter 92 and the left-side adapter 94, and is configured to be inclined at a second angle A2 with respect to the skid top surface P2. Similar to the first embodiment described above, the base 40b is inclined at a second angle A2 with respect to the landing plane LS. Therefore, with a simple configuration of a right-side adapter 92 and a left-side adapter 94, the rotation axis AX of the shaft 16 can be inclined with respect to the landing plane LS. Furthermore, in the helicopter 10 of this embodiment, the base 40b is connected to the first part 521 using the right-side adapter 92 and the left-side adapter 94. Therefore, for example, even when using an existing base 40b and cross tube 52, the user can use the right-side adapter 92 and the left-side adapter 94 to inclinate the rotation axis AX of the shaft 16 with respect to the landing plane LS.

[0090] C2. Variant: Figure 14 is a schematic explanatory diagram showing a modified example of the connecting mechanism 90c, namely the connecting mechanism 90c2. The connecting mechanism 90c2 differs from the connecting mechanism 90c shown in the third embodiment above in that it has one adapter 99 between the base 40b and the cross tube 52, instead of the right adapter 92 and the left adapter 94, and does not have a lower adapter 93. By configuring it in this way, the surface area of ​​the tip of the adapter 99 can be increased compared to the case where two adapters are provided, and the base 40b can be firmly supported.

[0091] As shown in Figure 14, for example, the fastening of the adapter 99 to the first part 521 and the fastening of the adapter 99 to the base 40b may be performed separately using multiple fasteners BN. Even with this configuration, the same effects as those of the third embodiment described above can be achieved.

[0092] D. Other embodiments: (D1) Figure 15 is a schematic diagram illustrating the connection structure between the skid 50d and the base 40a of the helicopter 10 according to another embodiment. In the second embodiment described above, an example was shown in which the first part 521b comprises a right-side projection 526, a left-side projection 528, and two lower projections 527. In contrast, as shown in Figure 15, the first part 521d may comprise only the right-side projection 526. Alternatively, the first part 521d may comprise only the left-side projection 528 instead of the right-side projection 526. A projection that is located on only one side of the first part 521d is also called a one-sided projection. In the example in Figure 15, the right-side projection 526 is an example of a one-sided projection. In this embodiment as well, the same effects as in the second embodiment described above can be obtained. Note that the configuration of the rear support and the rear first part is the same as the configuration of the front support 41 and the front first part 521d, so a description is omitted.

[0093] (D2) Figure 16 is a schematic diagram illustrating the connection structure between the skid 50 and the base 40a of the helicopter 10 according to another embodiment. In the third embodiment described above, an example was shown in which the connection mechanism 90c comprises a right-side adapter 92 and a left-side adapter 94. In contrast, as shown in Figure 16, the connection mechanism 90d may comprise only the right-side adapter 92. Alternatively, the connection mechanism 90d may comprise only the left-side adapter 94 instead of the right-side adapter 92. An adapter that is positioned on only one side of the first part 521 is also called a one-sided adapter. In the example in Figure 16, the right-side adapter 92 is an example of a one-sided adapter. The same effects as in the third embodiment described above can be obtained in this embodiment as well. Note that the configuration of the rear support and the rear first part is the same as the configuration of the front support 41 and the front first part 521, so a description is omitted.

[0094] This disclosure is not limited to the embodiments described above, and can be implemented in various forms without departing from its spirit. For example, this disclosure can also be implemented in the following forms (aspects). The technical features in the embodiments described above that correspond to the technical features in each of the forms described below can be replaced or combined as appropriate in order to solve some or all of the problems of this disclosure, or to achieve some or all of the effects of this disclosure. Furthermore, if such technical features are not described as essential in this specification, they can be deleted as appropriate.

[0095] (1) According to a first embodiment of the present disclosure, a single-rotor rotary-wing aircraft having a tail rotor is provided. The rotary-wing aircraft comprises a fuselage having a base located at the bottom, a shaft connected to the fuselage so as to rotate about a rotation axis inclined at a predetermined first angle with respect to the base, a main rotor connected to the shaft, and a landing gear that contacts a landing target when the rotary-wing aircraft is landing. The landing gear includes a pair of skid tubes defining the landing plane, and a pair of cross tubes connecting the pair of skid tubes, each having a first portion extending along the landing plane and a pair of second portions connecting the first portion to the pair of skid tubes. The base is directly or indirectly connected to the first portion in a manner inclined at a predetermined second angle with respect to the first portion such that the rotation axis is inclined with respect to the landing plane. In this configuration, the function of tilting the shaft's rotation axis relative to the landing plane can be integrated into the connection structure between the first part of the cross tube and the base. Therefore, the effects of lateral forces during takeoff of a rotary-wing aircraft can be suppressed or prevented with a simple configuration.

[0096] (2) In the rotary-wing aircraft described in embodiment (1) above, the base is provided on both the right and left sides of the base and comprises a right-side projection and a left-side projection that project from the base at different heights. The base is configured to be inclined at the second angle with respect to the first portion by being connected to the first portion via the right-side projection and the left-side projection. This configuration allows the base to be tilted relative to the landing plane through a simple structure in which the right-side protrusion and the left-side protrusion have different heights.

[0097] (3) In the rotary-wing aircraft described in embodiment (1) or embodiment (2) above, the base includes a pair of supports connected parallel to each other and each having a bottom surface. The right-side projection and the left-side projection are provided on the bottom surfaces of the pair of supports. According to this configuration, by providing the support connected to the first part in front and rear sections, the base can be made lighter compared to the case where a single, integrated base extending from the front to the rear is provided.

[0098] (4) In the rotary-wing aircraft according to any of the above embodiments (1) to (3), the base further comprises a pair of auxiliary supports connected to the pair of supports, each having a bottom surface. The first portion is connected to the bottom surface of the auxiliary support, the right projection, and the left projection. In this configuration, the support can be made smaller and lighter by connecting an auxiliary support to the main support and then connecting it to the first part.

[0099] (5) The rotary-wing aircraft according to any of the above embodiments (1) to (4) further comprises a connector including a first end connected to the right projection or the left projection, a second end connected to the bottom surface of the auxiliary support, and a recess defined between the first end and the second end. The connector is connected to the right projection or the left projection and the bottom surface of the auxiliary support with the first portion positioned in the recess. In this configuration, the user can connect the landing gear and the base by using a connector to connect the first part to the base, without performing any special processing on the landing gear for connection to the base.

[0100] (6) The rotary-wing aircraft according to any of the above embodiments (1) to (5) further comprises a fastener disposed in the recess, the fastener having a first contact surface that contacts either the tip surface of the right protrusion or the tip surface of the left protrusion, and a second contact surface that contacts the outer circumference of the first portion. In this configuration, the fixing device that makes surface contact with the tip surface of the protruding portion can suppress or prevent the first portion from rotating relative to the base.

[0101] (7) In a rotary-wing aircraft according to any of the above embodiments (1) to (6), the first portion comprises a right-side projection and a left-side projection provided on both the right and left sides of the upper end of the first portion, projecting from the first portion at different heights. The base is inclined at the second angle with respect to the first portion by being connected to the right-side projection and the left-side projection. According to this configuration, the rotation axis of the shaft can be tilted with respect to the accretion plane by a simple configuration that includes a protrusion on the first part.

[0102] (8) The rotary-wing aircraft according to any of the above embodiments (1) to (7) further comprises a right-side adapter and a left-side adapter, which are provided on both the right and left sides between the base and the first part and are of different heights from each other. The base is inclined at the second angle with respect to the first part by being connected to the first part via the right-side adapter and the left-side adapter. In this configuration, the rotation axis of the shaft can be tilted with respect to the accretion plane by a simple setup that includes a right-side adapter and a left-side adapter between the first part and the base.

[0103] (9) In the rotary-wing aircraft according to any of the above embodiments (1) to (8), the base is provided with a single-sided projection that protrudes from only one of the right or left sides of the base. On one side, it is connected to the first part via the single-sided projection, and on the other side, it is connected to the first part and tilted at the second angle with respect to the first part. This configuration allows the rotation axis of the shaft to be tilted with respect to the accretion plane by simply providing a protruding portion on one side.

[0104] (10) In a rotary-wing aircraft according to any of the above embodiments (1) to (8), the first portion is provided with a single-sided projection on only one of the right or left sides of the upper end of the first portion. On one side, it is connected to the first portion via the single-sided projection, and on the other side, it is directly connected to the first portion, thereby being inclined at the second angle with respect to the first portion. This configuration allows the rotation axis of the shaft to be tilted with respect to the accretion plane by simply providing a protruding portion on one side.

[0105] (11) The rotary-wing aircraft according to any of the above embodiments (1) to (8) further comprises a one-sided adapter provided on only one of the right or left sides between the base and the first part. The base is inclined at the second angle with respect to the first part by being connected to the first part via the one-sided adapter. This configuration allows the shaft's axis of rotation to be tilted relative to the accretion plane by simply providing an adapter on one side. [Explanation of Symbols]

[0106] 10...Helicopter, 12...Main rotor, 14...Tail rotor, 16...Shaft, 17...Hub, 18...Blade, 30...Airframe, 31...Body section, 32...Tail section, 40B, 40B2...Bottom surface, 40, 40a, 40b, 40b3...Base, 41...Front support, 41B...Bottom wall, 41b, 41b3...Front support, 42...Rear support, 43...Beam member, 44...Plate, 50, 50b, 50b2, 50b3, 50b4, 50d...Skid, 52, 52b, 52b2, 52b3, 52b4...Cross tube Skid tube, 54...Skid tube, 60...Restrictor, 61...Upper body part, 62...Lower body part, 70...Connector, 71...First end, 71H...Through hole, 72...Second end, 72H...Through hole, 74...Recess, 80...Fixing device, 81...Upper body part, 82...Lower body part, 90, 90c, 90c2, 90d...Connecting mechanism, 92...Right side adapter, 92T...Front end surface, 93...Lower adapter, 93B...Front end surface, 94...Left side adapter, 94T...Front end surface, 99...Adapter, 410...Front auxiliary support, 410B...Bottom surface, 410H ...Through hole, 412...Right side protrusion, 412B...Bottom, 412H...Through hole, 414...Left side protrusion, 414B...Bottom, 414H...Through hole, 417...Angle adjustment section, 420...Rear side auxiliary support, 420B...Bottom, 422...Right side protrusion, 422B...Bottom, 4 24...Left protrusion, 424B...Bottom surface, 521,521b,521b2,521b3,521b4,521d...First part, 522...Second part, 526...Right protrusion, 526T...Tip surface, 527...Lower protrusion, 527B...Tip surface, 528...Left protrusion Outward projection, 528T...tip surface, 529...projection, 529T...tip surface, 611...first end, 612...second end, 614...recess, 621...first end, 622...second end, 624...recess, 811...first contact surface, 812...second contact surface, 813...third contact surface, 816...wall surface, 822...lower inner surface, 823...lower outer surface, 826...wall surface, A1...first angle, A2...second angle, AX...rotation axis, B1, B2...bolt, BN...fastener, LS...accretion plane, N1, N2...nut, P1...virtual plane, P2...skid top surface

Claims

1. A single-rotor rotary-wing aircraft having a tail rotor, An aircraft having a base located at the very bottom, A shaft connected to the machine body so as to rotate around a rotation axis that is inclined at a predetermined first angle relative to the base, The main rotor connected to the aforementioned shaft, A landing gear that contacts the object to be landed on during the landing of the aforementioned rotary-wing aircraft, A pair of skid tubes defining the landing plane, An accretion device comprising a pair of cross tubes connecting the pair of skid tubes, each cross tube having a first portion extending along the accretion plane and a pair of second portions connecting the first portion and the pair of skid tubes, The base is inclined at a predetermined second angle relative to the first portion such that the axis of rotation is inclined with respect to the accretion plane, and is connected to the first portion directly or indirectly. Rotary-wing aircraft.

2. A rotary-wing aircraft according to claim 1, The aforementioned base is The base is provided with a right-side projection and a left-side projection, which are provided on both the right and left sides of the base and protrude from the base at different heights. The right-side projection and the left-side projection are connected to the first portion, and the second angle is inclined relative to the first portion. Rotary-wing aircraft.

3. A rotary-wing aircraft according to claim 2, The base includes a pair of supports connected parallel to each other and each having a bottom surface, The right-side protrusion and the left-side protrusion are provided on the bottom surface of the pair of supports. Rotary-wing aircraft.

4. A rotary-wing aircraft according to claim 3, The base further comprises a pair of auxiliary supports connected to the pair of supports, each having a bottom surface, The first portion is connected to the bottom surface of the auxiliary support, the right-side protrusion, and the left-side protrusion. Rotary-wing aircraft.

5. A rotary-wing aircraft according to claim 4, Furthermore, the connector includes a first end connected to the right-side projection or the left-side projection, a second end connected to the bottom surface of the auxiliary support, and a recess defined between the first end and the second end. The connector is connected to the right-side projection or the left-side projection and the bottom surface of the auxiliary support, with the first portion positioned in the recess. Rotary-wing aircraft.

6. A rotary-wing aircraft according to claim 5, Furthermore, the fastener disposed in the recess comprises a first contact surface that contacts either the tip surface of the right-side projection or the tip surface of the left-side projection, and a second contact surface that contacts the outer circumference of the first portion. Rotary-wing aircraft.

7. A rotary-wing aircraft according to claim 1, The first portion comprises a right-side projection and a left-side projection, which are provided on both the right and left sides of the upper end of the first portion and protrude from the first portion at different heights. The base is connected to the right-side projection and the left-side projection, and is inclined at the second angle with respect to the first portion. Rotary-wing aircraft.

8. A rotary-wing aircraft according to claim 1, Furthermore, the base and the first portion are provided with a right-side adapter and a left-side adapter, which are provided on both the right and left sides and have different heights from each other. The base is connected to the first portion via the right-side adapter and the left-side adapter, and is tilted at the second angle relative to the first portion. Rotary-wing aircraft.

9. A rotary-wing aircraft according to claim 1, The aforementioned base is The base is provided with a single-sided protrusion that protrudes from only one of the right or left sides, On one side, it is connected to the first portion via the one-sided protrusion, and on the other side, by being connected to the first portion, it is inclined at the second angle with respect to the first portion. Rotary-wing aircraft.

10. A rotary-wing aircraft according to claim 1, The first part is, The first portion comprises a single-sided projection provided on only one side, either the right or left side, of the upper end of the first portion, On one side, it is connected to the first portion via the one-sided protrusion, and on the other side, it is directly connected to the first portion, thereby inclined at the second angle with respect to the first portion. Rotary-wing aircraft.

11. A rotary-wing aircraft according to claim 1, Furthermore, it includes a single-sided adapter provided on only one side, either the right or left side, between the base and the first portion. The base is connected to the first portion via the one-sided adapter, thereby tilting at the second angle with respect to the first portion. Rotary-wing aircraft.

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