WO2014208680A1

WO2014208680A1 - Unmanned helicopter

Info

Publication number: WO2014208680A1
Application number: PCT/JP2014/067029
Authority: WO
Inventors: 正典吉原
Original assignee: ヤマハ発動機株式会社
Priority date: 2013-06-28
Filing date: 2014-06-26
Publication date: 2014-12-31
Also published as: JP2015009707A

Abstract

An unmanned helicopter (10) has a fuel tank (48) for holding fuel that is supplied to a drive source (36). The fuel tank (48) has a main unit (56) and a fuel holding unit (60). The fuel holding unit (60) protrudes obliquely downward to the left from the main unit (56). The fuel holding unit (60) is formed in a cylindrical shape, and a peripheral wall section (62) of the fuel holding unit (60) is formed so as to widen from the main unit (56) side towards a bottom (64) side. As seen from a drive shaft (44), the fuel holding unit (60) is provided on the side opposite a tail rotor (20). An opening (64a) of the fuel holding unit (60) is provided with a lid member (66), and the lid member (66) is provided with a fuel pump (52). The fuel pump (52) has a fuel suction port (72a) provided so as to face the inside of the fuel holding unit (60), and a pump main body (70) provided inside of the fuel tank (48).

Description

Unmanned helicopter

This invention relates to an unmanned helicopter, and more particularly to an unmanned helicopter equipped with a fuel tank.

An example of this type of prior art is disclosed in Patent Document 1.
Patent Document 1 discloses an unmanned helicopter including a fuel tank. In the case of an unmanned helicopter, in order to maintain the attitude of the aircraft with respect to the wind, the aircraft may fly while maintaining a state where the aircraft is tilted in a certain direction for a certain period of time.

Japanese Patent No. 4155454

By the way, in such an unmanned helicopter, it is required to be able to fly for a long time without reducing fuel consumption (without increasing the weight of the entire aircraft). For this purpose, it is conceivable to increase the amount of fuel that can be supplied from the fuel tank to the engine without increasing the capacity of the fuel tank (the weight of the fuel tank including the fuel).

In this case, even if the fuel suction port of the fuel pump is at the lower part of the fuel tank, the amount of fuel staying in the vicinity of the fuel suction port in the fuel tank is reduced during the flight, and as a result, the fuel pump draws air. Inhalation, fuel supply to the engine may become unstable.

Therefore, a main object of the present invention is to provide an unmanned helicopter capable of suppressing the fuel pump from sucking air regardless of the flight state.

According to a certain aspect of the present invention, the fuel tank includes a driving source, a main body and a fuel holding portion provided in the main body so as to protrude at least below the main body, and holds fuel supplied to the driving source. And a fuel pump having a fuel inlet provided so as to face the fuel holding portion, and the fuel holding portion is provided with an unmanned helicopter that protrudes downward from either the left side or the right side of the main body portion.

In the present invention, the fuel tank has the fuel holding portion protruding at least downward from the main body portion, so that the fuel can be held preferentially in the fuel holding portion rather than the main body portion. That is, even when there is no fuel in the main body part or when there is little, it becomes easy to secure the fuel in the fuel holding part. Therefore, the fuel in the fuel holding portion can be taken into the fuel pump from the fuel suction port, and the fuel pump can be prevented from sucking air regardless of the flight state.

Preferably, the fuel holding portion is formed in a cylindrical shape. In this case, it is easy to secure fuel in the fuel holding portion even when flying while maintaining a state where the unmanned helicopter (airframe) is tilted in the front-rear direction for acceleration or deceleration.

Further preferably, the fuel holding portion includes a peripheral wall portion extending from the main body portion and a bottom portion provided at an end portion of the peripheral wall portion, and the peripheral wall portion is formed to expand from the main body portion side toward the bottom portion side. In this case, even if the unmanned helicopter is tilted, it becomes easier to secure the fuel in the fuel holding portion.

More preferably, it further includes a tail rotor and a drive shaft for applying a driving force from a driving source to the tail rotor, the drive shaft extends in the front-rear direction, and the fuel holding portion is Provided on the opposite side. In this case, it is possible to balance the weight of the unmanned helicopter by providing the fuel holding portion and the tail rotor on the opposite side when viewed from the drive shaft.

Preferably, in a state where the unmanned helicopter has landed on a horizontal plane, a part of the fuel holding portion is located at the lowest position of the fuel tank. In this case, when the remaining amount of fuel in the fuel tank is low, even if the unmanned helicopter flies while maintaining a state tilted in a certain direction (for example, left or right), the fuel remains in the fuel holding portion. Therefore, fuel that does not contain air can be supplied to the fuel pump.

Preferably, in a state where the unmanned helicopter is landed on a horizontal plane, a virtual inverted cone whose apex is located at the fuel suction port of the fuel pump is arranged such that the generatrix of the inverted cone and the horizontal plane have a predetermined angle. The line of intersection between the fuel holding portion and the inverted conical surface is formed in an annular shape. In this case, the fact that the intersection line between the fuel holding portion and the conical surface is formed in an annular shape means that the fuel holding portion and the conical surface intersect over the entire circumference. In other words, it means that the fuel holding part has a part that rises from the conical surface (the angle with respect to the horizontal plane is large) over the entire circumference. Therefore, even if the unmanned helicopter continues to fly in an arbitrary direction at a predetermined angle (for example, 15 degrees) or less, all of the fuel does not flow out of the fuel holding portion and is held in the fuel holding portion. The fuel can be continuously supplied from the fuel inlet to the driving source.

More preferably, the fuel pump includes a pump body provided in the fuel tank. In this case, since the pump body of the fuel pump is provided in the fuel tank, the number of parts around the fuel tank can be reduced. Therefore, a more compact unmanned helicopter can be obtained.

Preferably, the fuel holding portion extends from the main body portion toward the outside in the left-right direction. In this case, the fuel holding portion extends outward and obliquely downward from the main body portion. Therefore, the fuel pump and the fuel inlet can be arranged at appropriate positions to continue supplying fuel to the drive source even if the unmanned helicopter continues to fly in a tilted state when there is little fuel remaining in the fuel tank.

Preferably, the fuel holding portion further includes an opening and a lid member provided in the opening, and the fuel pump is provided in the lid member. In this case, since the fuel pump is provided on the lid member and the fuel pump and the lid member can be attached and detached simultaneously, maintenance of the fuel pump and the fuel tank is facilitated.

More preferably, the drive source is an engine, and further includes a fuel injection device that supplies fuel to the engine. In the present invention, since the fuel pump can suppress the intake of air regardless of the flight state, even when the drive source is an engine supplied with fuel from the fuel injection device, the control of the engine air-fuel ratio remains stable. it can.

Preferably, the bottom part of the main body part is formed to be inclined downward toward the fuel holding part side. In this case, the fuel in the main body part flows toward the fuel holding part, and the fuel is easily collected in the fuel holding part.

Further preferably, a liquid level detection unit provided integrally with the fuel suction port for detecting the liquid level of the fuel in the fuel tank is further provided. In this case, since the liquid level detector is provided integrally with the fuel inlet, the remaining amount of fuel around the fuel inlet can be accurately detected. Furthermore, since a member for attaching the liquid level detection unit is not required separately, a more compact and lightweight unmanned helicopter can be obtained.

The above object and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the embodiments of the present invention given with reference to the accompanying drawings.

It is a side view showing an unmanned helicopter of one embodiment of this invention. It is a perspective view which shows a supply unit. It is a front view which shows a supply unit. It is a side view (figure seen from the left) which shows a supply unit. It is a side view (figure seen from the right) which shows a supply unit. It is a sectional view solution figure showing a supply unit. It is a cross-sectional schematic solution figure which shows a fuel pump and a fuel holding | maintenance part.

Hereinafter, an unmanned helicopter 10 (hereinafter abbreviated as helicopter 10) according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, front and rear, left and right, and top and bottom mean front and rear, left and right, and top and bottom based on the basic attitude of the helicopter 10. Here, the basic attitude of the helicopter 10 refers to the attitude of the helicopter 10 when the mast 14 is parallel to the vertical direction, in other words, the helicopter with the helicopter 10 landing on the horizontal plane. It corresponds to 10 postures. In the figure, “Fr” indicates the front, “Rr” indicates the rear, “R” indicates the right, and “L” indicates the left. In FIG. 7, in order to avoid the drawing from becoming complicated, constituent elements of a fuel pump 52 and a fuel holding unit 60 described later are shown in a simplified manner, and a liquid level detection sensor 76 described later is omitted. ing.

Referring to FIG. 1, helicopter 10 includes a main body 12, a mast 14, a main rotor 16, a tail body 18, and a tail rotor 20.

The main body 12 includes a frame 22, a body cover 24,

legs

26 and 28, and a pair of skids 30 (only the left skid 30 is shown in FIG. 1).

The frame 22 has a substantially rectangular shape in front view and extends in the front-rear direction. The tail body 18 and the body cover 24 are supported by the frame 22.

The

leg portions

26 and 28 are each formed in an inverted U shape when viewed from the front, and are supported by the frame 22. Specifically, the leg portions 26 are supported on both side surfaces of the frame 22 via a pair of support members 32 (only the left support member 32 is shown in FIG. 1) extending in the vertical direction. The leg portions 28 are supported on both side surfaces of the frame 22 via a pair of support members 34 (only the left support member 34 is shown in FIG. 1) extending in the vertical direction. In this embodiment, the pair of support members 34 extends to the upper side than the frame 22.

The pair of skids 30 are attached to the

legs

26 and 28 so as to be lined up on the left and right. Specifically, the skid 30 on one side (left side) is attached to the one side (left side) portion of the

legs

26 and 28, and the skid 30 (not shown) on the other side (right side) is attached to the leg portion 26. , 28 on the other side (right side).

The mast 14 is provided so as to protrude upward from the body cover 24 and to be rotatable. A main rotor 16 is fixed to the upper end portion of the mast 14. Thereby, the mast 14 and the main rotor 16 rotate integrally. The tail body 18 has a substantially cylindrical shape and extends rearward from the main body 12. The front end portion of the tail body 18 is supported by the rear end portion of the frame 22 in the body cover 24. The tail rotor 20 is rotatably provided at the rear end portion of the tail body 18.

The helicopter 10 further includes a drive source 36, a fuel injection device 38, a transmission 40, a supply unit 42, a drive shaft 44, and a control device 46. The drive source 36, the fuel injection device 38, the transmission 40 and the supply unit 42 are accommodated in the body cover 24.

The drive source 36 is supported on the front end of the frame 22 below the main rotor 16. In this embodiment, an engine is used as the drive source 36. More specifically, for example, a horizontally opposed multi-cylinder engine is used as the drive source 36. The fuel injection device 38 is provided in the drive source 36 and supplies fuel to the drive source 36.

The transmission 40 is supported by the frame 22 behind the drive source 36. The transmission 40 is connected to a crankshaft (not shown) of the drive source 36. A lower end portion of the mast 14 is connected to the transmission 40. The main rotor 16 rotates based on the driving force transmitted from the driving source 36 via the transmission 40 and the mast 14.

A drive shaft 44 is provided so as to extend rearward from the transmission 40. The drive shaft 44 extends in the front-rear direction in the main body 12 and the tail body 18. The tail rotor 20 is connected to the rear end portion of the drive shaft 44. In this embodiment, the tail rotor 20 is provided on the right side of the rear end portion of the drive shaft 44. The tail rotor 20 rotates based on the driving force transmitted from the driving source 36 via the transmission 40 and the drive shaft 44.

A supply unit 42 for supplying fuel to the drive source 36 is provided behind the mast 14. In this embodiment, the supply unit 42 supplies fuel to the drive source 36 via the fuel injection device 38. The supply unit 42 is supported by the upper ends of the pair of support members 34 above the frame 22. An upper end portion of the supply unit 42 (more specifically, a lid 50 (see FIG. 2) described later) is exposed upward from the main body 12.

A control device 46 is provided in the frame 22. The control device 46 controls various devices mounted on the helicopter 10. In this embodiment, the control device 46 controls various electrical components (not shown) based on the attitude of the helicopter 10 detected by an attitude detector (not shown), for example, and adjusts the attitude of the helicopter 10. .

2 to 5, the supply unit 42 includes a fuel tank 48, a lid 50, and a fuel pump 52. The fuel tank 48 includes an injection part 54, a main body part 56, a pair of

attachment parts

58 a and 58 b, and a fuel holding part 60, and holds fuel supplied to the drive source 36. The injection part 54 has a substantially cylindrical shape and is provided in the upper part of the fuel tank 48. The upper end of the injection part 54 opens upward. The lid 50 is attached to the injection portion 54 so as to close the upper end portion of the injection portion 54. The operator can inject fuel into the fuel tank 48 from the upper end of the injection part 54 with the lid 50 removed.

The main body portion 56 has a hollow substantially box shape and is provided at a substantially central portion of the fuel tank 48. The main body portion 56 includes a ceiling portion 56a, a front wall portion 56b, a rear wall portion 56c, a pair of

side wall portions

56d and 56e, and a bottom portion 56f. The ceiling part 56a is provided so as to extend in a substantially horizontal direction from the lower end part of the injection part 54. The front wall portion 56b extends downward from the front end portion of the ceiling portion 56a. The rear wall portion 56c extends downward from the rear end portion of the ceiling portion 56a. The pair of

side wall portions

56d and 56e extend downward from both side portions of the ceiling portion 56a. In this embodiment, the side wall portion 56d extends downward from the right end portion of the ceiling portion 56a and connects the front wall portion 56b and the rear wall portion 56c. The side wall part 56e extends downward from the left end part of the ceiling part 56a and connects the front wall part 56b and the rear wall part 56c. The bottom portion 56f is provided below the ceiling portion 56a so as to face the ceiling portion 56a. In this embodiment, the bottom portion 56f extends in a substantially horizontal direction so as to be connected to the front wall portion 56b, the rear wall portion 56c, the

side wall portions

56d and 56e, and the fuel holding portion 60.

Referring to FIG. 6, the bottom portion 56 f has an inclined surface 56 g that is inclined downward toward the fuel holding portion 60 side. The inclined surface 56 g is a surface facing the inside of the fuel tank 48. The inclined surface 56g is formed so as to be continuous with the inner surface 60a of the fuel holding portion 60. The angle A1 formed by the inclined surface 56g and the horizontal plane is preferably, for example, 3 degrees or more.

Referring to FIGS. 2 to 5, the pair of

attachment portions

58a and 58b have a hollow shape and project laterally (in the left-right direction) from the pair of

side wall portions

56d and 56e. In this embodiment, the attachment portion 58a protrudes rightward from the rear portion of the side wall portion 56d, and the attachment portion 58b protrudes leftward from the rear portion of the side wall portion 56e. The upper ends of the pair of support members 34 (see FIG. 1) are fixed to the

attachment portions

58a and 58b. Thus, the fuel tank 48 is supported by the frame 22 (see FIG. 1) via the pair of support members 34 (see FIG. 1).

Referring to FIGS. 1 and 3, in the width direction of helicopter 10, fuel holding portion 60 is provided on the side opposite to tail rotor 20 as viewed from drive shaft 44. In other words, in the width direction of the helicopter 10, the fuel holding portion 60 is provided on one side when viewed from the drive shaft 44, and the tail rotor 20 is provided on the other side. In this embodiment, the tail rotor 20 is provided on the right side of the drive shaft 44, and the fuel holding unit 60 is provided on the left side of the drive shaft 44.

Referring to FIGS. 2 to 6, fuel holding portion 60 has a cylindrical shape and protrudes downward from main body portion 56. In this embodiment, the fuel holding portion 60 protrudes downward from the left side of the main body portion 56. More specifically, the fuel holding part 60 protrudes obliquely downward to the left from the main body part 56. Accordingly, a part of the fuel holding portion 60 is located at the lowest position of the fuel tank 48 in a state where the helicopter 10 is landed on the horizontal plane.
Referring to FIGS. 3, 4, 6, and 7, fuel holding portion 60 includes a peripheral wall portion 62, a bottom portion 64, and a lid member 66.

The peripheral wall portion 62 has a substantially rectangular tube shape, extends downward from the main body portion 56 (in the present embodiment, diagonally downward to the left), and is connected to the outer edge of the bottom portion 64. That is, the bottom 64 is provided at the end of the peripheral wall 62. In this embodiment, the peripheral wall portion 62 is formed so as to expand from the main body portion 56 side toward the bottom portion 64 side. In other words, the inner surface 60a of the fuel holding portion 60 is formed so as to expand from the main body portion 56 side toward the bottom portion 64 side. The bottom 64 has an outer edge that is substantially polygonal (in this embodiment, substantially hexagonal). The bottom portion 64 has an annular portion 64b having an opening 64a at the center thereof, and a plurality (six in this embodiment) of concave portions 64c that are recessed from the annular portion 64b into the fuel holding portion 60. The recesses 64c are provided corresponding to a plurality (six in this embodiment) of screw holes 80c (see FIG. 7) described later. The lid member 66 is formed in a substantially disk shape, and the outer diameter of the lid member 66 is set larger than the inner diameter of the opening 64a.

6 and 7, the fuel pump 52 is attached to the lid member 66. The fuel pump 52 includes a substantially disc-shaped pedestal portion 68 provided on the upper surface of the lid member 66, a pump body 70 standing on the pedestal portion 68, and a side of the pump body 70 (right side in this embodiment). And a liquid strip detection sensor 76 provided on the pump main body 70 so as to protrude downward from the lid member 66. And a substantially L-shaped discharge portion 78 provided in the.

The lid member 66 and the pedestal portion 68 are arranged concentrically with each other, and the outer diameter of the pedestal portion 68 is set substantially equal to the inner diameter of the opening 64a.

The filter 74 is provided in contact with the suction part 72. The suction part 72 has a fuel suction port 72 a provided on the end face on the filter 74 side so as to face the fuel holding part 60.

The discharge unit 78 communicates with the pump main body 70 through the lid member 66 and the pedestal unit 68. The pump main body 70 includes a power generation device (for example, an electric motor) (not shown). The fuel in the fuel tank 48 is sucked from the suction portion 72 via the filter 74 and discharged from the discharge portion 78. Electric power from the battery is supplied to the power generation device of the pump body 70 via a connector portion (both not shown). Thereby, the pump main body 70 is driven.

The liquid level detection sensor 76 is a liquid level detection unit provided integrally with the fuel suction port 72a, and detects the level of the fuel in the fuel tank 48.

A support member 80 is attached to the lid member 66. The support member 80 is formed in an annular shape. The support member 80 has an outer edge formed in a substantially hexagonal shape and an inner edge formed in a circular shape. The support member 80 includes an outer peripheral portion 80a, an annular flange portion 80b formed inward from the inner edge of the outer peripheral portion 80a, and a plurality (six in this embodiment) of screw holes 80c formed in the outer peripheral portion 80a. And have. The inner diameter of the outer peripheral portion 80 a is set substantially equal to the outer diameter of the lid member 66, and the inner diameter of the flange portion 80 b is set smaller than the outer diameter of the lid member 66. The support member 80 is fitted to the lid member 66 such that the outer peripheral portion 80 a is in contact with the outer edge of the lid member 66 and the flange portion 80 b is in contact with the lower surface of the lid member 66.

The lid member 66 to which the fuel pump 52 and the support member 80 are thus attached is provided in the opening 64 a of the fuel holding unit 60.

At this time, a sealing member 86 such as an O-ring is disposed so as to surround the opening 64a in a state where the cap nut 82 is embedded and the nut 84 is disposed in each recess 64c of the bottom 64 of the fuel holding unit 60. Is done. In this state, the pump body 70 is inserted into the fuel tank 48 from the opening 64a of the bottom 64, and the screw holes 80c of the support member 80 are positioned so as to correspond to the recesses 64c, and the pedestal 68 is formed in the opening 64a. It is inserted. A plurality (six in this embodiment) of fastening members 88 such as bolts are inserted into the screw holes 80c and the sealing member 86 and attached to the nut 84 and the cap nut 82, respectively. In this way, the lid member 66 is provided on the bottom 64 of the fuel holding unit 60. Therefore, the fuel pump 52 is attached to the bottom portion 64 of the fuel holding portion 60 via the lid member 66. The sealing member 86 prevents the fuel in the fuel tank 48 from leaking from between the fuel holding unit 60 and the fuel pump 52.

The discharge unit 78 is connected to a fuel injection device 38 for supplying fuel to the drive source 36 via a fuel hose (not shown). The fuel in the fuel tank 48 is discharged by the fuel pump 52 and supplied to the fuel injection device 38 via the fuel hose. The fuel injection device 38 injects the fuel supplied from the fuel tank 48 into the drive source 36.

With reference to FIGS. 3 to 7, in such a supply unit 42, a virtual inverted cone B whose apex is located at the fuel inlet 72 a of the fuel pump 52 with the helicopter 10 landing on a horizontal plane. Is drawn so that the generatrix B1 of the inverted cone B and the horizontal plane have a predetermined angle A2, the intersecting line C between the fuel holding portion 60 and the conical surface B2 of the inverted cone B is formed in an annular shape. Referring to FIGS. 4 and 5, if both ends D1 and D2 of intersection line C shown in FIG. 4 are connected to both ends D1 and D2 of intersection line C shown in FIG. Easy to understand. The angle A2 is, for example, preferably 10 degrees or more, more preferably 15 degrees or more, and is set to 15 degrees in this embodiment.

According to such a helicopter 10, the fuel tank 48 includes the fuel holding portion 60 that protrudes at least downward from the main body portion 56, thereby preferentially holding fuel in the fuel holding portion 60 rather than the main body portion 56. It becomes easy. That is, even if there is no fuel in the main body portion 56 or a slight amount of fuel, it is easy to secure the fuel in the fuel holding portion 60. Therefore, the fuel in the fuel holding unit 60 can be continuously taken into the fuel pump 52 from the fuel suction port 72a, and the fuel pump 52 can be prevented from sucking air regardless of the flight state.

Since the fuel holding portion 60 is formed in a cylindrical shape, fuel is secured in the fuel holding portion 60 even when the helicopter 10 is tilted in the front-rear direction in order to accelerate or decelerate while flying for a certain period of time. It becomes easy to do.

Since the peripheral wall portion 62 of the fuel holding portion 60 is formed so as to expand from the main body portion 56 side toward the bottom portion 64 side, it becomes easier to secure fuel in the fuel holding portion 60 even if the helicopter 10 is tilted.

The weight balance of the helicopter 10 can be achieved by providing the fuel holding portion 60 and the tail rotor 20 on the opposite side when viewed from the drive shaft 44.

A part of the fuel holding unit 60 is located at the lowest position of the fuel tank 48. Therefore, when the remaining amount of fuel in the fuel tank 48 is small, even if the helicopter 10 flies while maintaining a state of being inclined in a certain direction (for example, left or right), the fuel remains in the fuel holding unit 60. Therefore, fuel that does not contain air can be supplied to the fuel pump 52.

The fact that the intersection line C between the fuel holding portion 60 and the conical surface B2 is formed in an annular shape means that the fuel holding portion 60 and the conical surface B2 intersect over the entire circumference. In other words, it means that the fuel holding part 60 has a part that rises from the conical surface B2 (the angle with respect to the horizontal plane is large) over the entire circumference. Therefore, even if the helicopter 10 continues to fly in an arbitrary direction with a predetermined angle A2 (for example, 15 degrees) or less, all of the fuel does not flow out of the fuel holding unit 60, and the fuel holding unit 60 The fuel held in the fuel can be continuously supplied to the drive source 36 from the fuel suction port 72a.

Since the pump body 70 of the fuel pump 52 is provided in the fuel tank 48, the number of parts around the fuel tank 48 can be reduced. Therefore, a more compact helicopter 10 is obtained.

The fuel holding portion 60 extends outward and obliquely downward from the main body portion 56. Accordingly, the fuel pump 52 and the fuel suction port 72a are placed at appropriate positions to continue supplying fuel to the drive source 36 even if the helicopter 10 continues to fly in a tilted state when the fuel remaining in the fuel tank 48 is small. Can be placed.

The fuel pump 52 is provided on the lid member 66, and the fuel pump 52 and the lid member 66 can be attached and detached at the same time. Therefore, maintenance of the fuel pump 52 and the fuel tank 48 is facilitated.

Since the fuel pump 52 can suppress the intake of air regardless of the flight state of the helicopter 10, even when the drive source 36 is an engine supplied with fuel from the fuel injection device 38, the control of the engine air-fuel ratio is stable. Can be maintained.

Since the bottom portion 56f of the main body portion 56 is formed so as to be inclined downward toward the fuel holding portion 60 side, the fuel in the main body portion 56 flows toward the fuel holding portion 60 and the fuel inside the fuel holding portion 60 is fueled. Tends to accumulate.

Since the liquid level detection sensor 76 is provided integrally with the fuel suction port 72a, the remaining amount of fuel around the fuel suction port 72a can be accurately detected. Furthermore, since a member for attaching the liquid level detection sensor 76 is not required separately, the helicopter 10 that is more compact and lightweight can be obtained.

Further, since the fuel can be held in the filter 74, the fuel can be reliably supplied from the fuel pump 52 by the drive source 36.

In the above embodiment, the case where the fuel holding portion 60 protrudes downward from the left side of the main body portion 56 has been described. However, the fuel holding portion may protrude downward from the right side of the main body portion. More specifically, the fuel holding portion may protrude obliquely downward to the right from the main body portion. Further, the shape of the fuel holding portion is not limited to the cylindrical shape, and may be a spherical shape or a cone shape, for example.

In the above-described embodiment, the case where one fuel holding portion 60 is provided in the main body portion 56 has been described, but the number of fuel holding portions is not limited to the above example. For example, a fuel holding part may be provided on each of the right and left sides of the main body part.

In the above-described embodiment, the case where the pump main body 70 of the fuel pump 52 is provided in the fuel tank 48 has been described, but the present invention is not limited thereto, and the pump main body 70 may be provided outside the fuel tank 48.

In the above-described embodiment, the case where the fuel injection device 38 is used as the means for supplying fuel to the drive source 36 has been described. However, the present invention is not limited to this, and a carburetor may be used.

In the above-described embodiment, the case where an engine is used as the drive source 36 has been described, but the drive source is not limited to the engine. For example, a motor and a fuel cell may be used as a drive source. In this case, the fuel supplied to the fuel cell is stored in the fuel tank 48.

Although the preferred embodiments of the present invention have been described above, it is apparent that various modifications can be made without departing from the scope and spirit of the present invention. The scope of the invention is limited only by the appended claims.

DESCRIPTION OF SYMBOLS 10 Unmanned helicopter 20 Tail rotor 36 Drive source 38 Fuel injection apparatus 44 Drive shaft 48 Fuel tank 52 Fuel pump 56

Main body part

56f, 64 Bottom part 60 Fuel holding part 62 Peripheral wall part 64a Opening part 66 Cover member 70 Pump main body 72a Fuel inlet port 76 Liquid level detection sensor A1, A2 Angle B Virtual inverted cone B1 Bus B2 Conical surface C Intersection line

Claims

A driving source;
A fuel tank for holding fuel to be supplied to the drive source, including a main body part and a fuel holding part provided in the main body part so as to protrude at least below the main body part;
A fuel pump having a fuel suction port provided so as to face the fuel holding portion;
The fuel holding part is an unmanned helicopter that protrudes downward from either the left side or the right side of the main body part.
The unmanned helicopter according to claim 1, wherein the fuel holding portion is formed in a cylindrical shape.
The fuel holding portion includes a peripheral wall portion extending from the main body portion and a bottom portion provided at an end portion of the peripheral wall portion, and the peripheral wall portion is formed to expand from the main body portion side toward the bottom portion side. The unmanned helicopter according to claim 1 or 2.
Tail rotor,
A drive shaft for applying a driving force from the driving source to the tail rotor;
The drive shaft extends in the front-rear direction,
The unmanned helicopter according to any one of claims 1 to 3, wherein the fuel holding portion is provided on a side opposite to the tail rotor as viewed from the drive shaft.
The unmanned helicopter according to any one of claims 1 to 4, wherein a part of the fuel holding portion is located at the bottom of the fuel tank in a state where the unmanned helicopter is landed on a horizontal plane.
With the unmanned helicopter landing on a horizontal plane, a virtual inverted cone whose apex is located at the fuel inlet of the fuel pump is set so that the generatrix of the inverted cone and the horizontal plane have a predetermined angle. 6. The unmanned helicopter according to claim 1, wherein an intersection line between the fuel holding portion and the conical surface of the inverted cone is formed in an annular shape.
The unmanned helicopter according to any one of claims 1 to 6, wherein the fuel pump includes a pump body provided in the fuel tank.
The unmanned helicopter according to any one of claims 2 to 7, wherein the fuel holding portion extends from the main body portion toward an outer side in a left-right direction.
The fuel holding portion further includes an opening and a lid member provided in the opening,
The unmanned helicopter according to any one of claims 1 to 8, wherein the fuel pump is provided in the lid member.
The unmanned helicopter according to any one of claims 1 to 9, wherein the drive source is an engine, and further includes a fuel injection device that supplies fuel to the engine.
The unmanned helicopter according to any one of claims 1 to 10, wherein a bottom portion of the main body portion is formed to be inclined downward toward the fuel holding portion side.
The unmanned helicopter according to any one of claims 1 to 11, further comprising a liquid level detection unit provided integrally with the fuel suction port in order to detect a liquid level of the fuel in the fuel tank.