Rotary wing aircraft

Abstract

This rotary wing aircraft comprises: an airframe having a base disposed at a lowermost part; a shaft connected to the airframe so as to rotate about an axis of rotation inclined at a predetermined first angle with respect to the base; a main rotor connected to the shaft; and landing gear that comes into contact with a landing target during landing of the rotary wing aircraft. This landing gear includes: a pair of skid tubes defining a landing plane; and a pair of cross tubes that connect the pair of skid tubes, and have 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 directly or indirectly connected to the first portion at a predetermined second angle with respect to the first portion such that the axis of rotation is inclined with respect to the landing plane.

Description

rotorcraft

[0001] The present disclosure relates to rotorcraft.

[0002] A single-rotor rotorcraft having a tail rotor is known. For example, GB Patent Application Publication No. 1045308 discloses a helicopter having an airframe configured to tilt at a predetermined angle relative to a landing plane on which the helicopter lands. When the rotorcraft is stopped on the landing plane, a shaft connecting the airframe and the main rotor is tilted at a predetermined angle relative to the landing plane.

[0003] A single-rotor rotorcraft may experience side forces due to the tail rotor immediately after takeoff. One possible solution is to tilt the rotorcraft's shaft at a predetermined angle relative to the landing plane and use the thrust of the tilted main rotor to suppress the effects of the side forces. However, prior art has not adequately considered a structure for tilting the main rotor and shaft relative to the landing plane.

[0004] Therefore, there is a demand for a technology that can tilt the main rotor and shaft with a simple configuration relative to the landing plane.

[0005] The present disclosure can be realized in the following forms.

[0006] According to a first aspect of the present disclosure, there is provided a single-rotor rotorcraft having a tail rotor. The rotorcraft includes: an airframe having a base disposed at its lowest position; a shaft connected to the airframe to rotate about a rotation axis inclined at a predetermined first angle relative to the base; a main rotor connected to the shaft; and a landing gear that contacts a landing target when the rotorcraft lands. The landing gear includes a pair of skid tubes that define the landing plane; and a pair of cross tubes connecting the pair of skid tubes, the pair of cross tubes 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 directly or indirectly connected to the first portion, inclined at a predetermined second angle relative to the first portion, so that the rotation axis is inclined relative to the landing plane.

[0007] 4 is an explanatory diagram showing a schematic configuration of a helicopter according to a first embodiment of the present disclosure. An explanatory diagram showing the external configuration of a skid and a base. An explanatory diagram showing the configuration of the bottom of the base. An explanatory diagram showing a connecting structure between the skid and the base. An exploded perspective view showing the configuration of a connecting mechanism. A cross-sectional view taken along line VI-VI in FIG. 4. A cross-sectional view taken along line VII-VII in FIG. 4. An explanatory diagram schematically showing a modified example of the base. An explanatory diagram schematically showing a connecting structure between a skid and a base provided in a helicopter according to a second embodiment of the present disclosure. An explanatory diagram schematically showing a modified example of a cross tube. An explanatory diagram schematically showing a second modified example of a cross tube. An explanatory diagram schematically showing a third modified example of a cross tube. The configuration of a connecting mechanism provided in a helicopter according to a third embodiment of the present disclosure will be described. An explanatory diagram schematically showing a connecting mechanism as a modified example of the connecting mechanism. An explanatory diagram schematically showing a connecting structure between a skid and a base provided in a helicopter according to another embodiment. FIG. 10 is a second explanatory diagram schematically illustrating a connection structure between a skid and a base of a helicopter according to another embodiment.

[0008] A. First Embodiment: Fig. 1 is an explanatory diagram showing a schematic configuration of a helicopter 10 according to a first embodiment of the present disclosure. The helicopter 10 is an example of a rotorcraft. As shown in Fig. 1, the helicopter 10 according to this embodiment includes an airframe 30, a shaft 16, a main rotor 12, a tail rotor 14, and a skid 50. The helicopter 10 is a single-rotor type having one main rotor 12. The tail rotor 14 cancels out the torque caused by the main rotor 12. Note that the helicopter 10 may be a manned rotorcraft or an unmanned rotorcraft.

[0009] The airframe 30 has an exterior shape that is elongated in one direction. The airframe 30 is provided with, for example, an engine, a main transmission, a tail drive shaft, and a tail transmission. The airframe 30 includes a trunk section 31 and a tail section 32 extending from the trunk section 31. A base 40 is provided at the bottom of the trunk section 31. A tail rotor 14 is provided at the tip of the tail section 32.

[0010] For ease of explanation, in this specification, with regard to the orientation of the helicopter 10, the longitudinal direction of the fuselage 30 when the helicopter 10 lands on a horizontal surface is defined as the fore-aft direction of the helicopter 10. Within the fore-aft direction, the side where the fuselage 31 of the fuselage 30 is located is defined as the front side, and the side where the tail section 32 is located is defined as the rear side. Among directions perpendicular to the fore-aft direction, the direction where the main rotor 12 is located is defined as the upper side and the side where the skid 50 is located is defined as the up-down direction. Furthermore, the direction perpendicular to the fore-aft direction and the up-down direction is defined as the left-right direction. In this case, the fore-aft direction and the left-right direction are parallel to the horizontal surface on which the helicopter 10 has landed.

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

[0012] The skid 50 is a so-called skid-type landing gear used when landing the helicopter 10. The skid 50 is an example of a landing gear. As will be described later, the skid 50 is connected to the base 40. 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 in a substantially straight line. The pair of skid tubes 54 are arranged spaced apart from each other in the left-right direction. The pair of skid tubes 54 come into contact with the landing target when the helicopter 10 lands on the landing target. The landing target may be, for example, the ground or a helicopter landing pad on a ship. The portions of the pair of skid tubes 54 that come into contact with the landing target define a landing plane LS. The landing plane LS is an imaginary plane that defines the attitude of the helicopter 10 after it has landed on the landing target, the orientation of each part of the helicopter 10, and the like. In this embodiment, the landing plane LS is parallel to the longitudinal and lateral directions.

[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 disposed spaced apart from each other in the fore-and-aft direction. One end of the cross tube 52 is connected to one of the skid tubes 54, and the other end is connected to the other skid tube 54. The cross tubes 52 absorb energy generated when the skid tubes 54 touch down during landing of the helicopter 10, thereby reducing impact on the airframe 30. The pair of cross tubes 52 includes a first portion 521 and a second portion 522. The following description will be given of a case in which the pair of front and rear cross tubes 52 have substantially the same shape, but the shape of the cross tubes 52 is not limited to this example. For example, the detailed shapes and dimensions of the front and rear cross tubes 52 may differ from each other.

[0015] The first portion 521 is indirectly connected to the base 40 via the connecting mechanism 90. When no load is applied, the first portion 521 extends in a direction parallel to the landing plane LS. In this embodiment, the first portion 521 extends in the left-right direction. The pair of first portions 521 are arranged parallel to and spaced apart from each other. Note that the first portion 521 may curve when a load such as a landing load is applied. Note that the load applied to the first portion 521 refers to various loads including, for example, the flight load of the helicopter 10 and the weight of the first portion 521 itself when the helicopter 10 is landing. When no load is applied to the first portion 521 refers to a case where none of the various loads described above is applied to the first portion 521. In the following description, based on the above-described definition of the load applied to the first portion 521, a case where no load is applied to each component of the helicopter 10 will be described as an example.

[0016] In this embodiment, the pair of first portions 521 define an imaginary plane that is substantially parallel to the landing plane LS when no load is applied. This imaginary plane that is substantially parallel to the landing plane LS when no load is applied is hereinafter also referred to as the skid upper surface. The skid upper surface is substantially parallel to the extension direction of the first portions 521.

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

[0018] The base 40 is fixed to the lowermost part of the fuselage 30, the trunk 31, by a connector or the like. The base 40 is formed of a metal such as an aluminum alloy. As shown in FIG. 2 , a 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 formed of a resin material such as FRP (Fiber Reinforced Plastics) instead of metal, or may include both a metal and a resin material.

[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] FIG. 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 the 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 extension direction of the first portion 521 of the front cross tube 52. As shown in FIG. 2, a right-side protrusion 412 is formed near the right end of the front support 41, protruding from the front support 41 toward the first portion 521. A left-side protrusion 414 is formed near the left end of the front support 41, protruding from the front support 41 toward the first portion 521.

[0021] As shown in FIG. 3 , the rear support 42 is connected to the rear cross tube 52 of the 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 extension 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 flush with each other. The rear support 42 is formed with a right-side protrusion 422 and a left-side protrusion 424 that are configured similarly to the right-side protrusion 412 and the left-side protrusion 414 described above. The detailed configuration of the rear support 42 is similar to that of the front support 41, and therefore will not be described here.

[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 approximately parallel. In this embodiment, the front support 41 and the rear support 42 are subjected to so-called lightening or thinning processing to reduce their weight. By connecting the lightweight front support 41 and the rear support 42 with the beam member 43, the weight of the base 40 can be reduced compared to when the front support 41, the rear support 42, and the beam member 43 are integrally formed. However, this is not limited thereto, and the front support 41, the rear support 42, the beam member 43, and the plate 44 may be formed, for example, from a single rectangular member.

[0023] 2 , in this embodiment, the base 40 further includes 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 protrusion 412 and the connecting mechanism 90 to the left protrusion 414. The rear auxiliary supports 420 are used to connect the connecting mechanism 90 to the right protrusion 422 and the connecting mechanism 90 to the left protrusion 424.

[0024] Fig. 4 is an explanatory diagram showing the connection structure between the skid 50 and the base 40. Fig. 4 shows the skid 50 and the base 40 as viewed from the front.

[0025] 4 shows a first angle A1 between the bottom surface 40B of the base 40 and the rotation axis AX. The bottom surface 40B of the base 40 refers to the lower surface of the base 40 defined by the lower end of the base 40 excluding the right protrusion 412, the left protrusion 414, the right protrusion 422, and the left protrusion 424. In this embodiment, the bottom surface 40B of the base 40 is an imaginary plane P1 defined by the bottom surfaces of the front support 41 and the rear support 42. The bottom surface 40B does not have to be flat, but may be curved. Alternatively, the bottom surface 40B may have a recess or a protrusion.

[0026] 4, in this embodiment, the rotation axis AX is perpendicular to the bottom surface 40B of the base 40. That is, the first angle A1 is approximately 90 degrees. However, the rotation axis AX does not necessarily have to be perpendicular to the bottom surface 40B of the base 40, and may be tilted to the left or right by a predetermined angle, such as 75 degrees, 80 degrees, or 85 degrees, from the state where it is perpendicular to the bottom surface 40B.

[0027] 4 , in this embodiment, the base 40 is connected to the first portion 521 of the cross tube 52 via a right protrusion 412 and a left protrusion 414. The right protrusion 412 has a bottom surface 412B, and the left protrusion 414 has a bottom surface 414B. The bottom surface 412B is an example of a tip surface of the right protrusion 412. The bottom surface 414B is an example of a tip surface of the left protrusion 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 front first portion 521 and is connected to the first portion 521. Similarly, in the rear support body 42 shown in FIG. 3 , the bottom surface 422B of the right protrusion 422 and the bottom surface 424B of the left protrusion 424 face the first portion 521 of the rear cross tube 52 and are connected to the first portion 521. The bottom surfaces 422B and 424B are examples of the tip surfaces of the right protrusion 422 and the left protrusion 424. In this way, the bottom surfaces 412B, 414B, 422B, and 424B are substantially coplanar and are connecting portions that connect the pair of first portions 521 to the base 40.

[0029] As shown in FIG. 4 , the distance from the bottom surface 40B of the base 40 to the bottom surface 412B of the right-side protrusion 412 is different from the distance from the bottom surface 40B of the base 40 to the bottom surface 414B of the left-side protrusion 414. In other words, the right-side protrusion 412 and the left-side protrusion 414 have different heights from the imaginary plane P1. In the example of FIG. 4 , the height of the right-side protrusion 412 is higher than the height of the left-side protrusion 414. The same is true for the right-side protrusion 422 and the left-side protrusion 424. Due to the difference in height between the right-side protrusion 412 and the left-side protrusion 414, the bottom surface 40B of the base 40, i.e., the imaginary plane P1, is inclined with respect to the skid upper surface P2.

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

[0031] The second angle A2 is set in consideration of a balance between obtaining sufficient thrust from the main rotor 12 for takeoff of the helicopter 10 and suppressing 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 can be obtained from the main rotor 12, and immediately after takeoff, the thrust of the tilted main rotor 12 can suppress lateral force caused by the thrust of the tail rotor 14.

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

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

[0034] As shown in FIG. 5 , the coupling mechanism 90 couples the first portion 521 of the cross tube 52 to the base 40. By using the coupling mechanism 90, a user can couple the cross tube 52 to the base 40 without having to perform any special processing on the cross tube 52 for coupling to the base 40. Therefore, by using the coupling mechanism 90, a user can couple an existing cross tube 52 to the base 40 without developing a cross tube with a special shape. In this case, the user can easily change the coupling position of the cross tube 52 to the base 40. Therefore, even if the user changes the lateral positions of the right protrusion 412 or the left protrusion 414 of the base 40, for example, the user can easily couple the cross tube 52 to a base 40 with a modified shape. As shown in FIG. 5 , the coupling mechanism 90 includes a coupler 70, a fixing device 80, and two restricting devices 60.

[0035] The connector 70 is a metal member having a generally U-shape. The connector 70, together with fasteners such as a bolt B1 and a nut N1, connects the cross tube 52 to the base 40. 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 disposed in the recess 74. In this embodiment, a fixing device 80 is disposed between the recess 74 and the first portion 521.

[0036] The first end 71 is disposed forward of the recess 74, and the second end 72 is disposed rearward of the recess 74. As shown in FIG. 5 , the first end 71 has a through hole 71H extending in the vertical direction. The second end 72 has a through hole 72H extending in the vertical direction. A bolt B1 is inserted through the through hole 71H. As shown in FIG. 6 , the bolt B1 inserted through the through hole 71H is then inserted into a through hole 412H formed in the bottom surface 412B of the right-side protruding portion 412 and fastened by a nut N1. As a result, the first end 71 is connected to the right-side protruding portion 412.

[0037] As shown in FIGS. 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 protruding portion 412 by fasteners BN, such as bolts. The front-to-rear width of the bottom surface 412B of the right protruding portion 412 is shorter than the distance from the through hole 71H to the through hole 72H in the connector 70. Therefore, the front-to-rear distance is insufficient using only the bottom surface 412B of the right protruding portion 412, and the first portion 521 cannot be connected using the connector 70. The front-to-rear width of the front support 41 and the right protruding portion 412 is set shorter than the distance from the through hole 71H to the through hole 72H in the connector 70 in order to minimize the shape of the front support 41 in order to reduce weight. In the manufacturing process of the front support body 41, forming the front support body 41 and then connecting the separate front auxiliary support body 410 has higher production efficiency than forming the front auxiliary support body 410 and the front support body 41 integrally.

[0038] The front auxiliary support 410 is connected to the rear side of the right protruding portion 412 so that the bottom surface 410B of the front auxiliary support 410 is flush with and located rearward of the bottom surface 412B of the right protruding portion 412. In other words, the front auxiliary support 410 has the function of extending the bottom surface 412B rearward. This makes it possible to reduce the size and weight of the front support 41 and improve the production efficiency of the front support 41.

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

[0040] Fig. 7 is a cross-sectional view taken along the line VII-VII in Fig. 4. As shown in Fig. 7, the front auxiliary support 410 is connected to the left protruding portion 414, similar to the right protruding portion 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 protruding portion 414 so that the bottom surface 410B of the front auxiliary support 410 is flush with the bottom surface 414B of the left protruding portion 414 and is located behind the bottom surface 414B.

[0041] 7 , the bolt B1 inserted through the through hole 71H of the first end 71 is inserted into a through hole 414H formed in the bottom surface 414B of the left protruding portion 414 and fastened with a nut N1. The bolt B1 inserted through the through hole 72H of the second end 72 is inserted into a through hole 410H formed in the bottom surface 410B of the front auxiliary support 410 and fastened with a nut N1. In this manner, the second end 72 of the connector 70 is indirectly connected to the left protruding portion 414 via the front auxiliary support 410 connected to the rear side of the left protruding portion 414. As a result, the connector 70 is fastened to the left protruding portion 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 FIG. 3 , in this embodiment, two rear auxiliary supports 420 are connected to the rear support 42 of the base 40, similar to the support 41. The rear auxiliary supports 420 differ from the front auxiliary support 410 in that their positions relative to the support are different. Other configurations of the rear auxiliary supports 420 are generally the same as those of the front auxiliary support 410. The two rear auxiliary supports 420 are connected to the front side of a right protrusion 422 and the front side of a left protrusion 424 of the rear support 42. Specifically, one rear auxiliary support 420 is connected to the front side of the right protrusion 422 so that the bottom surface 420B of the rear auxiliary support 420 is flush with and positioned in front of the bottom surface 422B of the right protrusion 422. The other rear auxiliary support 420 is connected to the front side of the left protruding portion 424 so that the bottom surface 420B of the rear auxiliary support 420 is flush with and positioned in front of the bottom surface 424B of the left protruding portion 424. In other words, like the front auxiliary support 410, the rear auxiliary support 420 has the function of extending the bottom surface 422B of the right protruding portion 422 and the bottom surface 424B of the left protruding portion 424 forward.

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

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

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

[0046] The first abutment surface 811 is a flat surface formed on the upper end of the upper main body portion 81. As shown in FIG. 6 , the first abutment surface 811 abuts against the bottom surface 412B of the right protrusion 412 and the bottom surface 410B of the front auxiliary support 410. By bringing the first abutment surface 811 into surface contact with the bottom surface 412B and the bottom surface 410B, it is possible to suppress or prevent the fixing device 80 from rotating relative to the base 40. Therefore, by using the connecting mechanism 90 including the fixing device 80, it is possible to suppress or prevent the first part 521 from rotating relative to the base 40.

[0047] 7 , the connecting mechanism 90 is connected to the left side protruding portion 414 in a similar configuration to the right side protruding portion 412. For example, the first abutment surface 811 abuts against the bottom surface 414B of the left side protruding portion 414 and the bottom surface 410B of the front auxiliary support 410. The connecting mechanism 90 connects the rear support 42 to the rear first portion 521 in a similar configuration to the left side protruding portion 414. The first abutment surface 811 of the right side protruding portion 422 abuts against the bottom surfaces 422B and 420B, similar to the right side protruding portion 412, and the first abutment surface 811 of the left side protruding portion 424 abuts against the bottom surfaces 424B and 420B, similar to the left side protruding portion 414.

[0048] 5 , in this embodiment, the connecting mechanism 90 further includes two restricting devices 60. The two restricting devices 60 are arranged on either side of the fixing device 80 in the left-right direction. The restricting devices 60 suppress or prevent the connecting device 70 and the fixing device 80 from moving relative to the first portion 521 in the extension direction of the first portion 521.

[0049] The restrictor 60 includes an upper main body portion 61 arranged to cover the upper side of the first portion 521, and a lower main body portion 62 arranged to cover the lower side of the first portion 521. The upper main body portion 61 and the lower main body portion 62 are each a metal member having a substantially U-shape.

[0050] The upper body portion 61 has a first end 611, a second end 612, and a recess 614 defined between the first end 611 and the second end 612. The lower body portion 62 has a first end 621, a second end 622, and a recess 624 defined between the first end 621 and the second end 622. The first end 611 and the first end 621 are fastened to each other by a bolt B2 and a nut N2. The second end 612 and the second end 622 are fastened to each other by a bolt B2 and a nut N2. That is, the upper body portion 61 and the lower body portion 62 are fastened to each other by the bolt and the nut with the first portion 521 disposed in the recess 614 and the recess 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 devices 60 that sandwich the first portion 521 are arranged on both sides of the connecting device 70 in the left-right direction, thereby restricting movement of the connecting device 70 and the fixing device 80 along the extension direction of the first portion 521. Therefore, it is possible to suppress or prevent movement of the skid 50 in the left-right direction relative to the base 40.

[0052] As described above, in the helicopter 10 of this embodiment, the base 40 is connected to the first portion 521 at a predetermined second angle A2 with respect to the first portion 521 so 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 inclined with respect to the landing plane LS can be used to offset 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 portion 521 of the cross tube 52, which is a part of the helicopter 10, and the base 40. Therefore, with a simple configuration, the influence of the lateral force during takeoff of the helicopter 10 can be suppressed or prevented.

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

[0054] In the helicopter 10 of this embodiment, the base 40 includes a front support 41 and a rear support 42 that are connected in parallel to each other. The right protrusion 412 and the left protrusion 414 are provided on the bottom surfaces 40B of the front support 41 and the rear support 42. By providing separate supports on the front and rear sides, the weight of the base 40 can be reduced compared to when an integrated base 40 extending from the front side to the rear side is provided.

[0055] In the helicopter 10 of this embodiment, the base 40 further includes 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 a bottom surface 412B of the right protruding portion 412, and to the bottom surface 410B and a bottom surface 414B of the left protruding portion 414. The rear first portion 521 is connected to the bottom surface 420B and a bottom surface 422B of the right protruding portion 422, and to the bottom surface 420B and a bottom surface 424B of the left protruding portion 424. By connecting auxiliary supports to the front support 41 and the rear support 42 and then 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 protruding portion 412 and the bottom surface 40B of the front auxiliary support 410 with the first portion 521 disposed in the recess 74. By using the connector 70, the skid 50 and the base 40 can be connected without having to process the skid 50 for connection to the base 40. Furthermore, because the position 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 is provided with a fastener 80 having a first abutment surface 811 that abuts against the bottom surface 412B of the right-side protrusion 412, a second abutment surface 812 that abuts against the outer periphery of the first portion 521, and a lower inner surface 822. By bringing the first abutment surface 811 into surface contact with the bottom surface 412B, it is possible to suppress or prevent the fastener 80 from rotating relative to the base 40. Therefore, by using a connecting mechanism 90 that includes the fastener 80, it is possible to suppress or prevent the first portion 521 from rotating relative to the base 40.

[0058] A2. Modifications: Figure 8 is an explanatory diagram schematically illustrating a modification of the base 40. In the first embodiment described above, an example was shown in which the front support 41 of the base 40 includes both the right protrusion 412 and the left protrusion 414. In contrast, the front support 41 may be configured to include only either the right protrusion 412 or the left protrusion 414. In this case, the rear support 42 includes only one of the two protrusions, the right protrusion 422 and the left protrusion 424, at a position corresponding to either the right protrusion 412 or the left protrusion 414 included in the front support 41. In other words, if the front support 41 includes only the right protrusion 412, the rear support 42 includes the right protrusion 422, and if the front support 41 includes only the left protrusion 414, the rear support 42 includes only the left protrusion 424.

[0059] In the following description, the configuration of the front support and the configuration of the front first portion will be described as an example, and a description of the configuration of the rear support and the configuration of the rear first portion will be omitted.

[0060] In the example of Fig. 8, the base 40a does not include the left protrusion 414, but only includes the right protrusion 412. A protrusion that is located on only the left or right side of the base 40a is also called a one-sided protrusion. In the example of Fig. 8, the right protrusion 412 is an example of a one-sided protrusion.

[0061] As shown in FIG. 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 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 those of the first embodiment can be obtained. Furthermore, the first portion 521 and the base 40a can be closer to each other than in the first embodiment.

[0062] B. Second embodiment: Figure 9 is an explanatory diagram schematically illustrating a connection structure between a skid 50b and a base 40b of a helicopter 10 according to a second embodiment of the present disclosure. The helicopter 10 of the second embodiment differs from the helicopter 10 of the first embodiment in that it includes a base 40b instead of the base 40 and a skid 50b instead of the skid 50, but otherwise has the same configuration. In Figure 9 and subsequent figures, the second angle A2 is illustrated as being larger than the actual angle to facilitate understanding of the technology.

[0063] The configuration of the base 40b differs from the configuration 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 the configuration of the front support 41 shown in the first embodiment in that it does not include the right protrusion 412 and the left protrusion 414. In other words, the bottom surface 40B of the front support 41b is generally flush across the entire surface from left to right. The configuration of the rear support is similar to that of the front support 41b, so a description thereof will be omitted. A skid 50b is connected to the bottom surface 40B by a connecting mechanism 90.

[0064] The configuration of the skid 50b differs from the configuration of the skid 50 shown in the first embodiment in that a cross tube 52b including a first portion 521b is provided instead of the cross tube 52 including the first portion 521. The first portion 521b differs from the first portion 521 shown in the first embodiment in that the first portion 521b further includes a right protrusion 526, two lower protrusions 527, and a left protrusion 528. The right protrusion 526, the lower protrusion 527, and the left protrusion 528 are, for example, integrally formed with the first portion 521b. The right protrusion 526 and the left protrusion 528 are provided near the right end and the left end of the first portion 521b, respectively. The configuration of the rear first portion is similar to that of the front first portion 521b, and therefore a description thereof will be omitted.

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

[0066] The right protrusion 526 has a tip surface 526T, and the left protrusion 528 has a tip surface 528T. The tip surfaces 526T and 528T are substantially flush with each other. The tip surface 526T contacts the bottom surface 40B of the front support 41b and is connected to the bottom surface 40B using, for example, a connecting mechanism 90. 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 body 41b and is connected to the bottom surface 40B using, for example, a connecting mechanism 90. The tip surface 528T is also fastened to the bottom surface 410B of the front auxiliary support body 410.

[0068] The two lower protrusions 527 are provided below the first portion 521b, on the right and left sides of the first portion 521b. More specifically, the two lower protrusions 527 are provided directly below the right protrusion 526 and directly below the left protrusion 528. The two lower protrusions 527 protrude downward from the first portion 521b. The two lower protrusions 527 have substantially the same configuration, and the distances from the first portion 521b to the tips of the lower protrusions 527 are substantially the same.

[0069] The lower protrusion 527 has tip surfaces 527B. The two tip surfaces 527B are approximately parallel to an imaginary plane P1 that passes through the tip surfaces 526T and 528T, respectively. This allows the user to fasten the tip surfaces 527B to 526T using a set of fasteners BN, such as a bolt and nut.

[0070] In the helicopter 10 of this embodiment, the first portion 521b includes a right protrusion 526 and a left protrusion 528 that are provided on both the right and left sides of the upper end of the first portion 521b and protrude from the first portion 521b at different heights. The base 40b is connected to the first portion 521b while being inclined at a predetermined second angle A2 with respect to the first portion 521b so that the rotation axis AX is inclined with respect to the landing plane LS. Therefore, similar to the first embodiment, the rotation axis AX of the shaft 16 can be inclined with respect to the landing plane LS by simply providing the protrusions on the cross tube 52b.

[0071] B2. Modification: Figure 10 is an explanatory diagram schematically illustrating a modification of the cross tube 52b. In the second embodiment, the lower protrusions 527 are provided on both the right and left sides of the lower end of the first section 521b. However, as shown in Figure 10, a lower adapter 93 may be provided instead of the lower protrusions 527.

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

[0073] The lower adapter 93 is included in the connecting mechanism 90. The lower adapter 93 has substantially the same external shape and function as the lower protrusion 527 shown in the second embodiment, but differs from the lower protrusion 527 in that the lower adapter 93 is separate from the first portion 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. More specifically, the two lower adapters 93 are disposed directly below the right protrusion 526 and the left protrusion 528. The two lower adapters 93 are disposed so as to protrude downward from the first portion 521b. The two lower adapters 93 have substantially the same configuration, and the distances from the first portion 521b to their respective tips are substantially the same.

[0075] The lower adapter 93 has a tip surface 93B. The two tip surfaces 93B are substantially parallel to an imaginary plane P1 that passes through the tip surface 526T and the tip surface 528T, respectively. This configuration allows the tip surface 93B to the tip surface 526T to be fastened using a set of fasteners BN, such as a bolt and nut. This embodiment also achieves the same effects as the second embodiment. The configuration of the rear first portion is similar to that of the front first portion 521b2, and therefore a description thereof will be omitted.

[0076] B3. Modification 2: Figure 11 is an explanatory diagram schematically illustrating a second modification of the cross tube 52b. In the second embodiment described above, a lower protrusion 527 is provided on each of the right and left sides of the lower end of the first section 521b. In contrast, in this embodiment, the helicopter 10 includes a base 40b3 and a skid 50b3. In particular, unlike the skid 50b2 shown in Figure 10, the skid 50b3 of this embodiment does not include a lower protrusion 527 at the lower end of the first section 521b3.

[0077] The skid 50b3 differs from the skid 50b shown in the second embodiment in that it includes a cross tube 52b3 including 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 include a lower protrusion 527. The lower end of the first portion 521b3 in the front view shown in Figure 11 is substantially linear and substantially parallel to the skid upper surface P2 and the extension direction of the first portion 521b3.

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

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

[0080] The angle adjustment portion 417 is a surface that is approximately parallel to the skid upper surface P2 and the extension direction of the first portion 521b3. This configuration allows for easy placement of fasteners BN that fasten the lower end of the first portion 521b3 to the angle adjustment portion 417, and allows for fastening from the tip surface 527B to the tip surface 528T using a set of fasteners BN, such as bolts and nuts. This embodiment also provides the same effects as the second embodiment. The configurations of the rear support body and the rear first portion are similar to those of the front support body 41b3 and the front first portion 521b3, and therefore will not be described here.

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

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

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

[0084] The base 40b3 is fastened by a fastener 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 configurations of the rear support body and the rear first portion are similar to the configurations of the front support body 41b3 and the front first portion 521b414, so a description thereof will be omitted.

[0085] C. Third Embodiment: Figure 13 illustrates the configuration of a coupling mechanism 90c provided in a helicopter 10 according to a third embodiment of the present disclosure. The helicopter 10 of the third embodiment differs from the helicopter 10 of the first embodiment in that it includes the base 40b shown in the second embodiment instead of the base 40, and in that it includes a coupling mechanism 90c instead of the coupling mechanism 90, but otherwise has the same configuration. The configurations of the rear support and the rear first section are similar to the configurations of the front support 41 and the front first section 521, and therefore will not be described here.

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

[0087] The right adapter 92 and the left adapter 94 are provided on the right and left sides, respectively, between the base 40b and the first portion 521. The right adapter 92 and the left adapter 94 have different heights. In this embodiment, the height of the right adapter 92 is greater than the height of the left adapter 94. Due to the height difference between the right adapter 92 and the left adapter 94, the bottom surface 40B is inclined with respect to the skid upper 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. An imaginary plane P1 passing through the tip surfaces 92T and 94T is substantially parallel to each of the tip surfaces 93B of the two lower adapters 93. The tip surfaces 92T and 94T contact the bottom surface 40B of the front support 41 and are connected to the bottom surface 40B using, for example, fasteners BN.

[0089] The helicopter 10 of this embodiment includes a right adapter 92 and a left adapter 94, which are provided on both the right and left sides between the base 40b and the first section 521 and are at different heights. The base 40b is connected to the first section 521 via the right adapter 92 and the left adapter 94, and is inclined at a second angle A2 with respect to the skid upper surface P2. As in the first embodiment, the base 40b is inclined at the second angle A2 with respect to the landing plane LS. Therefore, with the simple configuration of the right adapter 92 and the left 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 section 521 using the right adapter 92 and the left adapter 94. Therefore, for example, even when using an existing base 40b and cross tube 52, a user can use the right adapter 92 and the left adapter 94 to incline the rotation axis AX of the shaft 16 with respect to the landing plane LS.

[0090] C2. Modification: Figure 14 is an explanatory diagram schematically illustrating a coupling mechanism 90c2, which is a modification of the coupling mechanism 90c. The coupling mechanism 90c2 differs from the coupling mechanism 90c shown in the third embodiment in that a single adapter 99 is provided between the base 40b and the cross tube 52 instead of the right adapter 92 and the left adapter 94, and in that the lower adapter 93 is not provided. This configuration allows the area of ​​the tip surface of the adapter 99 to be larger than when two adapters are provided, allowing the base 40b to be more firmly supported.

[0091] 14, for example, a plurality of fasteners BN may be used to fasten the adapter 99 to the first portion 521 and the adapter 99 to the base 40b separately. Even in this configuration, the same effects as those of the third embodiment can be achieved.

[0092] D. Other Embodiments: (D1) Figure 15 is an explanatory diagram schematically illustrating a connection structure between a skid 50d and a base 40a of a helicopter 10 according to another embodiment. In the second embodiment, the first portion 521b includes a right protrusion 526, a left protrusion 528, and two lower protrusions 527. In contrast, as in the skid 50d shown in Figure 15, the first portion 521d may include only the right protrusion 526. Furthermore, the first portion 521d may include only the left protrusion 528 instead of the right protrusion 526. A protrusion disposed on only the left or right side of the first portion 521d is also referred to as a one-sided protrusion. In the example of Figure 15, the right protrusion 526 is an example of a one-sided protrusion. This embodiment can also achieve the same effects as the second embodiment. The configuration of the rear support and the rear first portion is similar to the configuration of the front support 41 and the front first portion 521d, and therefore description thereof will be omitted.

[0093] (D2) Figure 16 is an explanatory diagram schematically illustrating a connection structure between a skid 50 and a base 40a of a helicopter 10 according to another embodiment. In the third embodiment, the connection mechanism 90c includes a right adapter 92 and a left adapter 94. In contrast, the connection mechanism 90d shown in Figure 16 may include only the right adapter 92. Furthermore, the connection mechanism 90d may include only the left adapter 94 instead of the right adapter 92. An adapter disposed on only the left or right side of the first portion 521 is also referred to as a one-sided adapter. In the example shown in Figure 16, the right adapter 92 is an example of a one-sided adapter. This embodiment also achieves the same effects as the third embodiment. The configurations of the rear support and the rear first portion are similar to those of the front support 41 and the front first portion 521, and therefore will not be described here.

[0094] The present disclosure is not limited to the above-described embodiments and can be realized in various forms without departing from the spirit thereof. For example, the present disclosure can also be realized in the following aspects. The technical features in the above embodiments corresponding to the technical features in each aspect described below can be appropriately replaced or combined to solve some or all of the problems of the present disclosure or to achieve some or all of the effects of the present disclosure. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted.

[0095] (1) A first aspect of the present disclosure provides a single-rotor rotorcraft having a tail rotor. The rotorcraft includes an airframe having a base disposed at its lowest position; a shaft connected to the airframe to rotate about a rotation axis inclined at a predetermined first angle relative to the base; a main rotor connected to the shaft; and a landing gear that contacts a landing target when the rotorcraft lands. The landing gear includes a pair of skid tubes that define the landing plane; and a pair of cross tubes connecting the pair of skid tubes, the pair of cross tubes 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 directly or indirectly connected to the first portion in a state inclined at a predetermined second angle relative to the first portion so that the rotation axis is inclined relative to the landing plane. According to this aspect, the function of inclining the rotation axis of the shaft relative to the landing plane can be integrated into the connection structure between the first portion of the cross tube and the base. Therefore, with a simple configuration, the influence of lateral forces at the time of takeoff of the rotorcraft can be suppressed or prevented.

[0096] (2) In the rotorcraft described in the above aspect (1), the base includes a right protrusion and a left protrusion provided on both the right and left sides of the base, protruding from the base at different heights. The base is connected to the first portion via the right protrusion and the left protrusion, and is configured to incline at the second angle relative to the first portion. According to this aspect, the right protrusion and the left protrusion have a height difference, and this simple configuration allows the base to incline with respect to the landing plane.

[0097] (3) In the rotorcraft according to the above aspect (1) or (2), the base includes a pair of supports connected to each other in parallel, each having a bottom surface. The right protrusion and the left protrusion are provided on the bottom surfaces of the pair of supports. According to this aspect, by providing separate supports connected to the first portion on the front and rear sides, the weight of the base can be reduced compared to when an integrated base extending from the front side to the rear side is provided.

[0098] (4) In the rotorcraft according to any one of the above aspects (1) to (3), the base further includes a pair of auxiliary supports connected to the pair of supports, each having a bottom surface. The first portion is connected to the bottom surfaces of the auxiliary supports, the right protrusion, and the left protrusion. According to this aspect, by connecting the auxiliary supports to the supports and then to the first portions, the support can be made smaller and lighter.

[0099] (5) The rotorcraft according to any one of the above-described modes (1) to (4) further includes a connector including a first end coupled to the right protruding portion or the left protruding portion, a second end coupled to a bottom surface of the auxiliary support, and a recess defined between the first end and the second end. The connector is coupled to the right protruding portion or the left protruding portion and the bottom surface of the auxiliary support with the first portion disposed in the recess. According to this mode, by using the connector to connect the first portion to the base, a user can connect the landing gear to the base without performing any special processing on the landing gear for connection to the base.

[0100] (6) The rotorcraft according to any one of the above-described modes (1) to (5) further includes a fastener disposed in the recess, the fastener having a first abutment surface that abuts against the tip end surface of either the right protruding portion or the left protruding portion, and a second abutment surface that abuts against the outer periphery of the first portion. According to this mode, the fastener that comes into surface contact with the tip end surface of the protruding portion can suppress or prevent the first portion from rotating relative to the base.

[0101] (7) In the rotorcraft according to any one of the above-described modes (1) to (6), the first section includes a right-side protrusion and a left-side protrusion provided on both the right and left sides of an upper end of the first section and protruding from the first section at different heights. The base is connected to the right-side protrusion and the left-side protrusion, and is thereby inclined at the second angle relative to the first section. According to this mode, the rotation axis of the shaft can be inclined with respect to the landing plane by a simple configuration in which the protrusions are provided on the first section.

[0102] (8) The rotorcraft according to any one of the above aspects (1) to (7) further includes a right adapter and a left adapter, the right and left adapters being provided on the right and left sides between the base and the first section and having different heights. The base is connected to the first section via the right adapter and the left adapter, and is thereby inclined at the second angle relative to the first section. According to this aspect, the rotation axis of the shaft can be inclined with respect to the landing plane by a simple configuration in which the right adapter and the left adapter are provided between the first section and the base.

[0103] (9) In the rotorcraft according to any one of the above aspects (1) to (8), the base includes a one-sided protrusion protruding from only one of the right and left sides of the base. The one side is connected to the first portion via the one-sided protrusion, and the other side is connected to the first portion, thereby inclining at the second angle with respect to the first portion. According to this aspect, the rotation axis of the shaft can be inclined with respect to the landing plane by the simple configuration of providing the one-sided protrusion.

[0104] (10) In the rotorcraft according to any one of the above aspects (1) to (8), the first section includes a one-sided protrusion provided on only one of the right and left sides of an upper end of the first section. The one side is connected to the first section via the one-sided protrusion, and the other side is directly connected to the first section, thereby inclining the shaft at the second angle with respect to the first section. According to this aspect, the simple configuration of providing the one-sided protrusion allows the rotation axis of the shaft to be inclined with respect to the landing plane.

[0105] (11) The rotorcraft according to any one of the above aspects (1) to (8) further includes a one-sided adapter provided on only one of the right and left sides between the base and the first section. The base is connected to the first section via the one-sided adapter, and thereby inclined at the second angle relative to the first section. According to this aspect, the rotation axis of the shaft can be inclined with respect to the landing plane with the simple configuration of providing the one-sided adapter.

[0106] 10... helicopter, 12... main rotor, 14... tail rotor, 16... shaft, 17... hub, 18... blade, 30... fuselage, 31... fuselage 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... crosstube Tube, 54...skid tube, 60...regulating device, 61...upper body portion, 62...lower body portion, 70...connecting device, 71...first end portion, 71H...through hole, 72...second end portion, 72H...through hole, 74...recess, 80...fixing device, 81...upper body portion, 82...lower body portion, 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 part, 420...Rear side auxiliary support, 420B...Bottom, 422...Right side protrusion, 422B...Bottom, 4 24...Left side protrusion, 424B...Bottom surface, 521, 521b, 521b2, 521b3, 521b4, 521d...First portion, 522...Second portion, 526...Right side protrusion, 526T...Tip surface, 527...Lower side protrusion, 527B...Tip surface, 528...Left side protrusion protrusion, 528T...tip surface, 529...protrusion, 529T...tip surface, 611...first end, 612...second end, 614...recess, 621...first end, 622...second end, 624...recess, 811...first abutment surface, 812...second abutment surface, 813...third abutment 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...landing plane, N1, N2...nut, P1...imaginary plane, P2...skid upper surface

Claims

A single-rotor rotorcraft having a tail rotor, a body having a base disposed at the bottom; a shaft coupled to the airframe to rotate about a rotation axis inclined at a predetermined first angle relative to the base; a main rotor connected to the shaft; A landing gear that comes into contact with a landing target when the rotorcraft lands, a pair of skid tubes defining a landing plane; a landing gear including a pair of cross tubes connecting the pair of skid tubes, the pair of cross tubes 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 directly or indirectly connected to the first portion at a predetermined second angle such that the rotation axis is inclined relative to the landing plane; Rotorcraft.

2. The rotorcraft of claim 1, The base is a right protrusion and a left protrusion provided on both the right and left sides of the base and protruding from the base at different heights; the right protrusion and the left protrusion are connected to the first portion, and are thereby inclined at the second angle relative to the first portion; Rotorcraft.

3. The rotorcraft of claim 2, the base includes a pair of supports connected in parallel to each other, each having a bottom surface; The right protrusion and the left protrusion are provided on bottom surfaces of the pair of supports. Rotorcraft.

4. The rotorcraft of claim 3, The base further includes a pair of auxiliary supports connected to the pair of supports, each having a bottom surface; The first portion is connected to a bottom surface of the auxiliary support, the right protrusion, and the left protrusion. Rotorcraft.

5. The rotorcraft of claim 4, a connector including a first end connected to the right protruding portion or the left protruding portion, a second end connected to a 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 protruding portion or the left protruding portion and the bottom surface of the auxiliary support body with the first portion disposed in the recess. Rotorcraft.

6. The rotorcraft of claim 5, The fixing device further includes a fixing member disposed in the recess, the fixing member 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 periphery of the first portion. Rotorcraft.

2. The rotorcraft of claim 1, the first portion includes a right protrusion and a left protrusion provided on both the right and left sides of an upper end of the first portion and protruding from the first portion at different heights; the base is connected to the right protrusion and the left protrusion, and is thereby inclined at the second angle relative to the first portion; Rotorcraft.

2. The rotorcraft of claim 1, The present invention further includes a right adapter and a left adapter, which are provided on both the right and left sides between the base and the first portion and have different heights, the base is connected to the first portion via the right adapter and the left adapter, and is thereby inclined at the second angle relative to the first portion; Rotorcraft.

2. The rotorcraft of claim 1, The base is a one-side protrusion protruding from only one of the right and left sides of the base, the one side is connected to the first portion via the one-side protrusion, and the other side is connected to the first portion, thereby being inclined at the second angle relative to the first portion; Rotorcraft.

2. The rotorcraft of claim 1, The first portion is a one-side protrusion provided on only one of the right and left sides of the upper end of the first portion, the one end is connected to the first portion via the one-side protrusion, and the other end is directly connected to the first portion, thereby being inclined at the second angle relative to the first portion; Rotorcraft.

2. The rotorcraft of claim 1, The device further includes a one-sided adapter provided on only one of the right and left sides between the base and the first portion, the base is connected to the first portion via the one-sided adapter, and is thereby inclined at the second angle relative to the first portion; Rotorcraft.

Images