Compound helicopter

Abstract

To provide a composite helicopter that allows for efficient operation of the main rotor with a simple configuration. [Solution] The composite helicopter of the present invention comprises a fuselage, a main rotor, a forward thruster, and a backward thruster. The main rotor is mounted on the upper part of the fuselage and rotates in a predetermined rotational direction when viewed from above, with a variable pitch angle. The forward thruster has forward rotor blades mounted on the side of the fuselage, on the forward side when the main rotor moves forward. The backward thruster has backward rotor blades mounted on the side of the fuselage, on the backward side when the main rotor moves backward. When flying forward, both the forward and backward rotor blades rotate in the opposite direction to the predetermined rotational direction when viewed from the front of the fuselage.

Description

[Technical Field]

[0001] This invention relates to a composite helicopter. [Background technology]

[0002] Patent documents 1 and 2 describe a composite helicopter equipped with a main rotor and a pair of left and right side propellers. In these composite helicopters, the left and right side propellers generate thrust for the aircraft and also play a role in adjusting the counter-torque in the yaw direction caused by the rotation of the main rotor.

[0003] As another example of a composite helicopter equipped with side propellers, Patent Document 3 describes a rotary-wing aircraft equipped with a tail propeller in addition to the left and right side propellers. In this rotary-wing aircraft, the left and right side propellers mainly adjust the counter-torque in the yaw direction caused by the rotation of the main rotor, while the tail propeller is responsible for generating thrust for the aircraft. By dividing the roles of each propeller in this way, the operating efficiency of the propellers can be increased.

[0004] When a helicopter, including the composite helicopters described above, flies forward, a dynamic pressure difference occurs between the forward and backward sides of the main rotor. This dynamic pressure difference is known to cause an imbalance in the lift generated by the main rotor, resulting in a rolling moment that causes the aircraft to rotate in the roll direction. One method known to suppress the rolling moment is cyclic pitch control, which resolves the lift imbalance by changing the pitch angle of the blades that make up the main rotor according to the azimuth angle.

[0005] In addition, Patent Document 4 describes a method of using a dual counter-rotating rotor as a way to suppress the rolling moment associated with the rotation of the main rotor. In this method, the two main rotors rotate in opposite directions to cancel out the rolling moments caused by the rotation of each main rotor. [Prior art documents] [Patent Documents]

[0006] [Patent Document 1] European Patent No. 3141478 [Patent Document 2] Japanese Patent Publication No. 2021-115925 [Patent Document 3] Japanese Patent Publication No. 2024-000086 [Patent Document 4] European Patent No. 3201085 [Overview of the Initiative] [Problems that the invention aims to solve]

[0007] The cyclic pitch control described above constantly changes the pitch angle of the main rotor blades. Therefore, it is difficult to maintain the optimal pitch angle for the main rotor during operation. Furthermore, a larger pitch angle control amount is likely to reduce the efficiency of the main rotor as a rotor blade. On the other hand, while mechanisms like contra-rotating rotors reduce the amount of cyclic pitch control, their complexity may increase manufacturing costs and reduce maintainability. Therefore, there is a need for technology that enables efficient operation of the main rotor with a simple configuration.

[0008] In view of the above circumstances, the object of the present invention is to provide a composite helicopter that can efficiently operate the main rotor with a simple configuration. [Means for solving the problem]

[0009] To achieve the above objective, a composite helicopter according to one embodiment of the present invention comprises a fuselage, a main rotor, a forward thruster, and a reverse thruster. The main rotor is located on the upper part of the fuselage and rotates in a predetermined rotational direction when viewed from above, with a variable pitch angle. The forward-facing thruster has forward-facing rotor blades located on the side of the fuselage, on the forward side from which the main rotor moves forward. The retractable thruster has a retractable rotor blade located on the side of the fuselage, on the side where the main rotor moves backward. The forward-moving rotor blade and the backward-moving rotor blade both rotate in the opposite direction to the predetermined rotation direction when viewed from the front of the fuselage during forward flight.

[0010] In this composite helicopter, the main rotor is mounted on the upper part of the fuselage, and on the sides of the fuselage, forward-facing thrusters with forward-facing rotors and backward-facing thrusters with backward-facing rotors are mounted on the forward and backward sides of the main rotor, respectively. The main rotor has a variable pitch angle and rotates in a predetermined direction when viewed from above the fuselage. During forward flight, both the forward-facing and backward-facing rotors rotate in the opposite direction to the predetermined rotation when viewed from the front of the fuselage. This cancels out the rolling moment caused by the rotation of the main rotor, making it possible to reduce the amount of control required for the pitch angle of the main rotor, for example. As a result, it is possible to operate the main rotor efficiently with a simple configuration.

[0011] The thrust direction of at least one of the forward thrusters and the reverse thrusters may be set in a direction inclined with respect to the forward direction of the composite helicopter such that a moment in the predetermined rotational direction is generated when the fuselage is viewed from the front.

[0012] Both the forward-moving rotor blade and the backward-moving rotor blade may be propellers. In this case, the forward-moving thruster may be positioned such that the front end of the rotation axis of the forward-moving rotor blade points downward with respect to the forward direction.

[0013] Both the forward-moving rotor blade and the backward-moving rotor blade may be propellers. In this case, the backward-moving thruster may be positioned such that the front end of the rotation axis of the backward-moving rotor blade points upward with respect to the forward direction.

[0014] The composite helicopter may further comprise a pair of main wing sections extending to the left and right from the fuselage. In this case, the forward thrusters may be provided on the forward-facing main wing sections. The backward thrusters may be provided on the backward-facing main wing sections.

[0015] Both the forward-facing rotor and the backward-facing rotor may be propellers with a variable pitch angle. In this case, the forward-facing thruster and the backward-facing thruster may change the thrust by rotating each rotor at a constant rotational speed during forward flight and changing the pitch angle of each rotor.

[0016] The composite helicopter may further include a rear thruster having a rear rotor located at the rear of the fuselage and rotating in a direction opposite to the predetermined rotation direction when viewed from the front.

[0017] As described above, the present invention makes it possible to operate the main rotor efficiently with a simple configuration. The effects described herein are not necessarily limited, and any of the effects described in this disclosure may be used. [Brief explanation of the drawing]

[0018] [Figure 1] This is a schematic diagram showing an example of the configuration of a composite helicopter according to the first embodiment of the present invention. [Figure 2] This is a schematic diagram illustrating the rolling moment caused by the rotation of the main rotor. [Figure 3] This is a schematic diagram showing the relationship between the rotation direction of the main rotor and the direction of the rolling moment. [Figure 4] This is a schematic diagram illustrating cyclic pitch control. [Figure 5] This graph shows an example of pitch angle control in cyclic pitch control. [Figure 6] This is a schematic diagram showing the relationship of moments in a composite helicopter, which is presented as a comparative example. [Figure 7]This is a schematic diagram showing the relationship of moments in the composite helicopter according to this embodiment. [Figure 8] This graph shows the control amount of the pitch angle in the composite helicopter of this embodiment. [Figure 9] This graph shows the relationship between lift offset and main rotor performance. [Figure 10] This graph shows the relationship between the rolling moment and velocity in a compound helicopter. [Figure 11] This is a schematic diagram showing an example of the configuration of a composite helicopter according to the second embodiment. [Figure 12] This is a schematic diagram showing an example configuration of a composite helicopter according to the third embodiment. [Modes for carrying out the invention]

[0019] Hereinafter, embodiments of the present invention will be described with reference to the drawings.

[0020] <First Embodiment> [Configuration of a composite helicopter] Figure 1 is a schematic diagram showing an example of the configuration of a composite helicopter according to the first embodiment of the present invention. Figure 1A is a perspective view of the composite helicopter 100. Figure 1B is a side view of the composite helicopter 100 as seen from the left side. Figure 1C is a side view of the composite helicopter 100 as seen from the same direction as in Figure 1B, showing the right side configuration as seen through the aircraft (fuselage section 10).

[0021] The composite helicopter 100 is a helicopter equipped with thrusters in addition to the main rotor 15. The composite helicopter 100 according to this embodiment is capable of takeoff and landing, forward flight, turning, hovering, and the like. The composite helicopter 100 may be manned or unmanned. As shown in Figure 1A, the composite helicopter 100 has a fuselage 10, a pair of main wing sections 11, a main rotor 15, a pair of side thrusters 20, and a rear thruster 30.

[0022] In the following, the direction of the rotation axis Cm that rotates the main rotor 15 will be referred to as the Z direction, the direction perpendicular to the Z direction and corresponding to the front-to-back direction of the composite helicopter 100 will be referred to as the X direction, and the direction perpendicular to both the X and Z directions will be referred to as the Y direction. The Y direction corresponds to the left-to-right direction of the composite helicopter 100.

[0023] The fuselage section 10 is a structural element that constitutes the airframe of the composite helicopter 100. The fuselage section 10 is, for example, configured symmetrically and has a shape that extends in the front-rear direction with a bulge near the center. The fuselage section 10 is provided with a main drive mechanism (not shown) that drives the main rotor 15. The rotation axis Cm of the main rotor 15 is the central axis of the shaft member (main drive shaft) that is rotated by the main drive mechanism.

[0024] A pair of main wing sections 11 are provided extending from the fuselage section 10 to the left and right. Each main wing section 11 has a predetermined airfoil cross-section and functions as a wing that generates lift during forward flight of the composite helicopter 100. The pair of main wing sections 11 are connected symmetrically to, for example, the central portion of the fuselage section 10. Furthermore, the composite helicopter 100 according to this embodiment can be described as a winged composite helicopter provided with main wing sections 11.

[0025] The main rotor 15 is a rotor blade that generates the lift necessary for the flight of the composite helicopter 100, and is located on the upper part of the fuselage 10. The main rotor 15 is a rotor blade having multiple rotor blades 16. Each rotor blade 16 is a plate-shaped member that is long in one direction, and its base end is attached to the main drive shaft. The rotor blades 16 are arranged at equal intervals along the circumferential direction (around the Z axis) and are arranged to extend radially from the main drive shaft. In the example shown in the figure, there are four rotor blades, but the number of rotor blades 16 is not particularly limited. Hereafter, each rotor blade 16 may be referred to as the main rotor 15.

[0026] The main rotor 15 also rotates in a predetermined rotational direction when viewed from above the fuselage 10. In this disclosure, the rotational direction 14 of the main rotor 15 is defined as clockwise (right-hand rotation) or counterclockwise (left-hand rotation) when viewed from above the fuselage 10 on which the main rotor 15 is installed (i.e., when the rotational plane is viewed from above). The rotational direction 14 of the main rotor (the predetermined rotational direction) as defined in this way is referred to as the first rotational direction. The rotational direction opposite to the first rotational direction is referred to as the second rotational direction.

[0027] For example, if the first rotation direction is counterclockwise, the right side (starboard side) of the composite helicopter 100 is the advancing side, where the main rotor 15 moves forward (from the tail to the nose), and the left side (port side) of the composite helicopter 100 is the retreating side, where the main rotor 15 moves backward (from the nose to the tail). Conversely, if the first rotation direction is clockwise, the right side of the composite helicopter 100 is the retreating side of the main rotor 15, and the left side is the advancing side of the main rotor 15.

[0028] In this embodiment, as shown in Figure 1, a configuration in which the main rotor 15 rotates counterclockwise when viewed from above (a configuration in which the first direction of rotation is counterclockwise) will be described. Note that the present invention can also be applied even if the first direction of rotation is clockwise. In this case, the relationship between the direction of each rotation and the forward and reverse sides in the following description should be reversed.

[0029] Furthermore, the main rotor 15 has a variable pitch angle. The pitch angle of the main rotor 15 is, for example, the angle of inclination of the rotor blade 16 with respect to the main drive shaft to which the rotor blade 16 is attached, with respect to the longitudinal direction of the rotor blade 16 (see Figure 4, etc.). The main rotor 15 is a variable-pitch rotor blade configured so that its pitch angle is variable during rotation. By changing the pitch angle, the lift generated by the rotor blade 16 can be changed. The pitch angle of the main rotor 15 is controlled, for example, by cyclic pitch control, which will be described later.

[0030] The pair of side thrusters 20 are thrusters provided in pairs on both the left and right sides of the fuselage section 10. Each side thruster 20 has a side drive mechanism 21 and a side propeller 22. The side drive mechanism 21 has a side drive shaft (not shown) that rotates around a predetermined axis of rotation.

[0031] The side propeller 22 is a rotor having multiple propeller blades 23. The propeller blades 23 are plate-shaped members that are long in one direction, and their base ends are attached to the side drive shaft of the side drive mechanism 21. The propeller blades 23 are arranged at equal intervals along the circumferential direction (around the Z axis) and are arranged to extend radially from the side drive shaft. In the example shown in the figure, there are four propeller blades 23, but the number of propeller blades 23 is not particularly limited. Also, in Figure 1, the side propeller 22 is provided in front of the side drive mechanism 21 in each side thruster 20, but the side propeller 22 may be provided behind the side drive mechanism 21.

[0032] The side thruster 20 is a propeller thruster that generates thrust along the axis of rotation by rotating the side propeller 22 using the side drive mechanism 21. Therefore, the direction along the axis of rotation is the direction of thrust from the side thruster. The forward and backward direction of the thrust can be appropriately set according to, for example, the rotation direction and pitch angle of the side propeller 22.

[0033] In the composite helicopter 100 shown in Figure 1, the rotation direction 14 (first rotation direction) of the main rotor 15 is counterclockwise, the right side of the composite helicopter 100 is the forward side of the main rotor 15, and the left side is the reverse side of the main rotor 15. In this case, the right side propeller 22 is a forward-rotating blade located on the side of the fuselage 10 where the main rotor 15 moves forward, and the right side thruster 20 is a forward-rotating thruster having a forward-rotating blade. The left side propeller 22 is a reverse-rotating blade located on the side of the fuselage 10 where the main rotor 15 moves backward, and the left side thruster 20 is a reverse-rotating thruster having a reverse-rotating blade.

[0034] Hereinafter, the main wing sections 11 located on the right and left sides of the fuselage section 10 will be referred to as main wing section 11A and main wing section 11R, and the side thrusters 20 located on the right and left sides of the fuselage section 10 will be referred to as forward thruster 20A and backward thruster 20R, respectively. The side propellers 22 located on the forward thruster 20A and backward thruster 20R will be referred to as forward propeller 22A and backward propeller 22R, respectively. The rotation axis Cs of the forward propeller 22A and backward propeller 22R will be referred to as rotation axis CsA and rotation axis CsR.

[0035] As shown in Figure 1A, in this embodiment, the forward thruster 20A is provided on the forward-facing main wing section 11A (right main wing section 11). The backward-facing thruster 20R is provided on the backward-facing main wing section 11R (left main wing section 11). Therefore, the main wing sections 11A and 11R function as support members that support each side thruster 20 relative to the fuselage section 10. Specifically, the forward-facing thruster 20A and the backward-facing thruster 20R are attached to the wingtips of each main wing section 11A and 11R. This allows for an increase in the distance between the point of force application (side thruster 20) and the point of application (fuselage section 10), thereby efficiently applying the thrusting moment from the side thrusters 20 to the fuselage section 10.

[0036] In this embodiment, both the forward-facing propeller 22A and the reverse-facing propeller 22R are propellers with variable pitch angles. Here, the pitch angle of the side propeller 22 is, for example, the inclination angle of the propeller blade 23 with respect to the side drive shaft to which the propeller blade 23 is attached, with respect to the longitudinal direction of the propeller blade 23. By changing the pitch angle of the propeller blade 23, the thrust can be changed even at the same rotational speed.

[0037] In the composite helicopter 100, the forward thruster 20A and the reverse thruster 20R rotate their respective side propellers 22 (22A and 22R) at a constant rotational speed during forward flight, changing the thrust by altering the pitch angle of each side propeller 22 (22A and 22R). This allows for easy control of the thrust provided by, for example, the forward thruster 20A and the reverse thruster 20R.

[0038] The rear thruster 30 is a thruster located at the rear of the fuselage 10. The rear thruster 30 comprises a rear drive mechanism (not shown) and a rear propeller 31. The rear propeller 31 is a rotor with multiple propeller blades 32 and is a tail propeller located at the rear end (tail) of the fuselage 10. In the example shown in the figure, there are three propeller blades 32, but the number of propeller blades 32 is not particularly limited. The rear thruster 30 is a propeller thruster that generates thrust along the rotation axis Ct by rotating the rear propeller 31 around the rotation axis Ct using the rear drive mechanism. In this embodiment, the rear propeller 31 corresponds to the rear rotor.

[0039] [Rotation direction of each propeller and thrust direction of each thruster] The following describes the direction of propeller rotation and the direction of thrust for each thruster (forward thruster 20A, backward thruster 20R, and rear thruster 30) provided on the composite helicopter 100. In this disclosure, the direction of propeller rotation is represented by a thin annular arrow in each drawing, and the moment generated by the rotation of the propeller is represented by a thick annular arrow.

[0040] In the composite helicopter 100, for a pair of side thrusters 20, both the rotation direction of the forward propeller 22A and the backward propeller 22R, and the thrust direction of the forward thruster 20A and the backward thruster 20R are set to generate a moment in a first rotational direction when viewed from the front of the fuselage 10 during forward flight. In other words, the rotation direction and thrust direction of the pair of side thrusters 20 are set so that when viewed from the front of the fuselage 10, a moment with the same rotational direction as the main rotor 15 when viewed from above is generated.

[0041] In the following, as shown in Figure 1A, the rotation directions of the forward propeller 22A and the reverse propeller 22R will be described as rotation direction 24A and rotation direction 24R, respectively. Also, as shown in Figures 1B and 1C, the thrust directions of the forward thruster 20A and the reverse thruster 20R will be described as thrust direction 26A and thrust direction 26R, respectively.

[0042] First, with reference to Figure 1A, the rotation directions of the forward-facing propeller 22A and the backward-facing propeller 22R will be explained. When the aircraft is flying forward, both the forward-facing propeller 22A and the backward-facing propeller 22R rotate in the opposite direction to the first rotation direction (the second rotation direction) when viewed from the front of the fuselage 10. Here, as shown in Figure 1A, since the first rotation direction is counterclockwise, the rotation direction 24A of the forward-facing propeller 22A and the rotation direction 24R of the backward-facing propeller 22R, as viewed from the front, are both set to clockwise.

[0043] Generally, when a rotor blade, such as a propeller, rotates, due to the principle of action and reaction, a moment acting on the aircraft supporting the rotor blade has a rotational direction opposite to that of the rotor blade. In the following, the moment generated by the rotation of a propeller may be referred to as propeller torque. In the example shown in Figure 1A, when the forward-moving propeller 22A rotates, a moment (propeller torque 18A) is generated around the rotation axis CsA in a counterclockwise direction (first rotational direction) when viewed from the front, and similarly, when the backward-moving propeller 22R rotates, a moment (propeller torque 18R) is generated around the rotation axis CsR in a counterclockwise direction (first rotational direction) when viewed from the front (see Figure 7).

[0044] Furthermore, if the rotation direction 14 (first rotation direction) of the main rotor 15 is clockwise, the left-right positional relationship of the forward propeller 22A and the reverse propeller 22R is reversed, and the rotation direction of each propeller as viewed from the front is set to counterclockwise. In this case, the rotation of the forward propeller 22A and the reverse propeller 22R generates a moment around the rotation axis CsA and rotation axis CsR that rotates clockwise (first rotation direction) as viewed from the front.

[0045] Thus, in the composite helicopter 100, the rotation of each side propeller 22 generates moments (propeller torques 18A and 18R) in the same rotational direction as the main rotor 15, both on the forward and backward sides of the main rotor 15.

[0046] The rotation directions 24A and 24R described above are rotation directions set at least during forward flight. For example, during takeoff, landing, or hovering maneuvers, control may be performed to rotate one of the side propellers 22 in the opposite direction to the first rotation direction in order to suppress yaw rotation (rotation around the rotation axis Cm of the main rotor 15).

[0047] Next, with reference to Figures 1B and 1C, the thrust direction generated by the forward thruster 20A and the reverse thruster 20R will be described. In this embodiment, the thrust directions 26A and 26R of both the forward thruster 20A and the reverse thruster 20R are set to a direction inclined with respect to the forward direction 12 of the composite helicopter 100, such that a first rotational moment is generated when the fuselage 10 is viewed from the front.

[0048] Here, the forward direction 12 of the composite helicopter 100 is the direction of travel as viewed from the fuselage 10 during forward flight. Therefore, the forward direction 12 is defined, for example, in accordance with the attitude of the composite helicopter 100 (fuselage 10) during forward flight. In this embodiment, the forward direction 12 is set parallel to the longitudinal direction (X direction) of the fuselage 10. That is, the forward direction 12 is the direction (X direction) perpendicular to the rotation axis Cm (Z direction) of the main rotor 15. The direction of the forward direction 12 is from the tail side to the nose side.

[0049] For example, in a single-rotor helicopter, it is necessary to tilt the rotation axis Cm of the main rotor with respect to the horizontal plane to obtain thrust for forward movement. In contrast, in a composite helicopter 100, thrust for forward movement is obtained from propulsion systems other than the main rotor, so it is possible to set the forward direction 12 perpendicular to the rotation axis Cm as described above. This makes it possible to perform forward flight while keeping the fuselage 10 (XY plane) of the composite helicopter 100 horizontal. However, even in the composite helicopter 100, it is also possible to configure it to move forward or backward by tilting the rotation axis Cm of the main rotor with respect to the horizontal plane while keeping the fuselage 10 horizontal, similar to a conventional single-rotor helicopter.

[0050] It should be noted that the forward direction 12 of the composite helicopter 100 is not limited to the example described above. For example, when flying forward with the nose tilted downward, the forward direction 12 is set to a direction that is directed upwards from the front-to-back direction (X direction) of the fuselage 10. In this way, the forward direction 12 as seen from the fuselage 10 is set appropriately according to the attitude of the fuselage 10 during forward flight.

[0051] When the thrust direction 26A (or thrust direction 26R) is inclined with respect to the forward direction 12, it means that the thrust direction 26A (or thrust direction 26R) is set to be inclined vertically with respect to the forward direction 12. This is a state in which the forward direction 12 and the thrust direction 26A (or thrust direction 26R) intersect in the XZ plane. In this case, the thrust of the forward thruster 20A (or reverse thruster 20R) is divided into a component parallel to the forward direction 12 (X-direction component) and a component perpendicular to the forward direction 12 (Z-direction component).

[0052] The thrust component perpendicular to the forward direction 12 generates a moment acting on the fuselage 10, as will be explained below. In the composite helicopter 100, the thrust directions 26A and 26R are set such that this moment, when viewed from the front of the fuselage 10, becomes a moment in the first rotational direction.

[0053] In the following, the angle between the thrust direction 26A (or thrust direction 26R) and the forward direction 12 will be referred to as the inclination angle θt. The inclination angle θt is defined as 0° when the thrust direction 26A (or thrust direction 26R) and the forward direction 12 coincide, with the angle above the forward direction 12 being considered positive and the angle below being considered negative.

[0054] Since the forward thrusters 20A and the reverse thrusters 20R are propeller thrusters, the direction of the rotation axis of each propeller is the direction of the thrust force. Therefore, the direction of the rotation axis CsA of the forward thruster 22A is the thrust force direction 26A, and the direction of the rotation axis CsR of the reverse thruster 22R is the thrust force direction 26R.

[0055] As shown in Figure 1B, the reversing thruster 20R (left-side thruster 20) is positioned such that the front end of the rotation axis CsR of the reversing propeller 22R points upward with respect to the forward direction 12. Here, the reversing thruster 20R is positioned inclined with respect to the X direction so that its front end points upward. Therefore, the inclination angle θt is a positive angle.

[0056] This results in increased thrust T from the reversing propeller 22R. RSThis is the component Fx parallel to the forward direction 12. RS And the upward component Fz, which is perpendicular to the forward direction 12. RS It can be divided into two parts. In other words, when the fuselage section 10 is viewed from the front, there is an upward force Fz at the wingtip of the left main wing section 11. RS This is what acts on it. When viewed from the front of the fuselage 10, this generates a moment that rotates the fuselage 10 itself counterclockwise (first rotation direction). In this way, the reversing thruster 20R can generate a moment in the first rotation direction by tilting its thrust direction 26R (rotation axis CsR) upward.

[0057] As shown in Figure 1C, the forward thruster 20A (right-side thruster 20) is positioned such that the front end of the rotation axis CsA of the forward propeller 22A points downward with respect to the forward direction 12. Here, the forward thruster 20A is positioned at an angle with respect to the X direction such that its front end points downward. Therefore, the inclination angle θt is a negative angle.

[0058] This results in increased thrust T from the forward propeller 22A. AS This is the component Fx parallel to the forward direction 12. AS And the downward component Fz perpendicular to the forward direction 12 AS It can be divided into two parts. In other words, when the fuselage section 10 is viewed from the front, there is a downward force Fz at the wingtip of the right main wing section 11. AS This is what acts. This generates a moment that rotates the fuselage 10 itself counterclockwise (first rotation direction) when viewed from the front, similar to the case in Figure 1B. In this way, the forward thruster 20A can generate a moment in the first rotation direction by tilting its thrust direction 26A (rotation axis CsA) downward.

[0059] The method of attaching the retractable thruster 20R and the forward thruster 20A is not limited. For example, the retractable thruster 20R and the forward thruster 20A may be fixed to the wingtip of the main wing section 11 at an inclination angle that satisfies the above conditions. The inclination angle θt of the retractable thruster 20R and the forward thruster 20A may also be variable. In this case, the inclination angle θt of the retractable thruster 20R and the forward thruster 20A relative to the main wing section 11 is adjusted by an angle adjustment mechanism (not shown). When the inclination angle θt is variable in this way, it is also possible to configure the helicopter 100 to change the inclination angle θt to satisfy the above conditions when it is flying forward.

[0060] In the following, the moment generated due to the inclination of the thrust direction in the forward thruster 20A and the reverse thruster 20R may be referred to as the thrust moment. The thrust moment, together with the propeller torque described above, constitutes the moment generated by the forward thruster 20A and the reverse thruster 20R.

[0061] The thrust direction of the rear thruster 30 is the rotation axis Ct of the rear propeller 31, and this direction is set parallel to the forward direction 12. The rotation direction 24T of the rear propeller 31 is set clockwise, as with the other propellers. In other words, the rear propeller 31 rotates in the opposite direction to the first rotation direction (second rotation direction) when viewed from the front. As a result, the rotation of the rear propeller 31 generates a moment (propeller torque 18T) around the rotation axis Ct in a counterclockwise direction (first rotation direction) when viewed from the front.

[0062] With this configuration, each thruster in the composite helicopter 100 generates a moment with an axis in the X direction. This moment with an axis in the X direction becomes a rolling moment that acts in the direction that causes the composite helicopter 100 to roll. Hereinafter, the rolling moments generated by the forward thruster 20A, the reverse thruster 20R, and the rear thruster 30 will be referred to as rolling moment 17A, rolling moment 17R, and rolling moment 17T, respectively.

[0063] The rolling moment 17A includes the propeller torque 18A generated by the rotation of the forward propeller 22A and the propulsive force moment 19A generated by the downward component Fz AS of the propulsive force T AS The rolling moment 17R includes the propeller torque 18R generated by the rotation of the reverse propeller 22R and the propulsive force moment 19R generated by the upward component Fz RS of the propulsive force T RS The rolling moment 17T includes the propeller torque 18T generated by the rotation of the rear propeller 31. In this embodiment, since the rotation axes of the forward propeller 22A and the reverse propeller 22R are inclined with respect to the X direction, the propeller torques 18A and 18R are the X-direction components of the propeller torques centered on the respective rotation axes CsA and CsR.

[0064] [Rolling Moment due to Rotation of Main Rotor] FIG. 2 is a schematic diagram for explaining the rolling moment due to the rotation of the main rotor. FIG. 3 is a schematic diagram showing the relationship between the rotation direction 14 of the main rotor and the direction of the rolling moment. Hereinafter, referring to FIGS. 2 and 3, the rolling moment 17M generated by the rotation of the main rotor 15 during forward flight will be described.

[0065] In FIG. 2, a map of the thrust (lift) generated by the rotation of the main rotor 15 during forward flight is illustrated in gray scale. Here, the closer the color of the map is to black, the greater the thrust.

[0066] In Figure 2, the rotation angle Ψ when the rotor blades 16 are facing backward is defined as 0°. The main rotor 15 rotates counterclockwise, and the rotor blades 16 are directed to the right, forward, and left when Ψ = 90°, 180°, and 270°, respectively. In this case, the rotor receives wind from the direction of Ψ = 180° (forward side) according to the flight speed. Also, with Ψ = 90° as the center, the right side of the main rotor 15 is the forward side where the rotor blades 16 move forward. Conversely, with Ψ = 270° as the center, the left side of the main rotor 15 is the backward side where the rotor blades 16 move backward.

[0067] It is known that when a rotary-wing aircraft equipped with a main rotor 15, such as a compound helicopter or a helicopter, flies forward, the magnitude of the dynamic pressure (available wind force) acting on the main rotor 15 is asymmetrical on the left and right sides. Specifically, the dynamic pressure is greater on the forward side of the main rotor 15, and conversely, it is smaller on the backward side. This difference in dynamic pressure between the left and right sides results in a difference in the thrust distribution on the main rotor 15.

[0068] In the example shown in Figure 2, the main rotor 15 rotates counterclockwise when viewed from above, resulting in higher dynamic pressure on the right side (around Ψ=90°) and consequently higher thrust. Conversely, the dynamic pressure on the left side (around Ψ=270°) decreases, resulting in lower thrust. Therefore, the position of the rotor thrust (the point of application of rotor thrust), which is the sum of the thrusts generated by the entire main rotor 15, shifts to the forward side (in this case, the right side) where the dynamic pressure is higher than the central axis Cm.

[0069] Therefore, if the main rotor 15 is rotated while its rudder angle (pitch angle) is fixed without adjustment, the thrust generated on the forward side will be greater, resulting in a rolling moment 17M that tilts the fuselage 10 toward the backward side.

[0070] Figure 3 illustrates the correspondence between the rotation direction 14 of the main rotor 15 and the rolling moment 17M. As shown in Figure 3A, when the rotation direction 14 (first rotation direction) of the main rotor 15, as viewed from above, is counterclockwise, the right side of the fuselage 10 becomes the forward side and the left side becomes the backward side. In this case, during forward flight, a rolling moment 17M is generated that rotates the fuselage 10 in a direction where the left side is downward, i.e., a rolling moment 17M that rotates clockwise when the fuselage 10 is viewed from the front.

[0071] On the other hand, as shown in Figure 3B, when the rotation direction 14 (first rotation direction) of the main rotor 15 as viewed from above is clockwise, the right side of the fuselage 10 becomes the backward side and the left side becomes the forward side, the opposite to Figure 3A. In this case, during forward flight, a rolling moment 17M is generated that rotates the fuselage 10 in a direction where the right side is downward, that is, a rolling moment 17M that rotates counterclockwise when the fuselage 10 is viewed from the front.

[0072] Thus, in a rotary-wing aircraft equipped with a main rotor 15, a rolling moment 17M is generated during forward flight. Furthermore, the direction of rotation of the rolling moment 17M as viewed from the front is opposite (second direction of rotation) to the direction of rotation 14 (first direction of rotation) of the main rotor 15 as viewed from above.

[0073] [Cyclic pitch control] Figure 4 is a schematic diagram illustrating cyclic pitch control. In single-rotor helicopters, including compound helicopters, cyclic pitch control is performed to maintain the aircraft's attitude during flight. Cyclic pitch control is a control method that changes the pitch angle θp of the rotor blades 16 of the main rotor 15 according to the azimuth angle φ.

[0074] It is generally known that the larger the pitch angle θp of a rotor blade 16, the greater the lift it generates. Based on this principle, the difference in thrust between the left and right sides can be suppressed by reducing the pitch angle θp in areas with high dynamic pressure and increasing the pitch angle θp in areas with low dynamic pressure. Specifically, as shown in Figure 4, control is performed to reduce the pitch angle θp on the forward side and increase the pitch angle θp on the reverse side.

[0075] Figure 5 is a graph showing an example of pitch angle control in cyclic pitch control. The horizontal axis of the graph represents the azimuth angle Ψ, which represents the rotational position of the rotor blade 16, and the vertical axis represents the pitch angle θp of the rotor blade 16 at each azimuth angle φ. Here, a pitch angle θp = 4° is used as the reference angle. For example, the rotor blade 16 is designed to obtain thrust most efficiently when the pitch angle θp is set to the reference angle. This means, for example, that the ratio of thrust (lift) generated by the rotor blade 16 to the drag force acting on the rotor blade 16 is maximized. Therefore, the closer the pitch angle θp is to the reference angle, the higher the aerodynamic performance of the rotor blade 16.

[0076] The dotted line graph in Figure 5 represents the pitch angle θp when cyclic pitch control is not performed. For example, during hovering, unlike forward flight, there is no difference in thrust between the left and right sides. Therefore, cyclic pitch control is not performed, and as shown in the dotted line graph, the pitch angle θp is set to a reference angle regardless of the azimuth angle φ. This allows the main rotor 15 to be operated most efficiently.

[0077] The solid line graph in Figure 5 represents the pitch angle θp when cyclic pitch control is performed, and the pitch angle θp changes in a sinusoidal shape with a period of one rotation of the azimuth angle φ. Here, as shown in Figure 4, it is assumed that the main rotor 15 rotates counterclockwise. For example, when Ψ=0° and Ψ=180°, θp is set to the reference angle. Also, at Ψ=90°, when the dynamic pressure is highest, θp is set to the smallest angle (here, -2°) so that the thrust is lowest. Conversely, at Ψ=90°, when the dynamic pressure is highest, θp is set to the largest angle (here, +10°) so that the thrust is highest. Note that the angles shown here are just examples, and the control amount (also called the steering amount) of the pitch angle θp in cyclic pitch control may be set appropriately depending on the shape of the rotor blade 16 and the usage conditions of the main rotor 15.

[0078] As shown in Figure 4, when cyclic pitch control is not performed, the rotor thrust 40 (white arrow) is shifted forward from the center of the main rotor 15. In contrast, when cyclic pitch control is performed according to the profile shown in Figure 5, for example, the thrust imbalance between the forward and backward sides is mitigated, and the rotor thrust 40 moves towards the center of the main rotor 15. This makes it possible to reduce or eliminate the rolling moment 17M that rotates the aircraft in the roll direction. As a result, it becomes possible to maintain the aircraft's attitude in the roll direction. Thus, cyclic pitch control is an example of lift offset technology that shifts the point of application of rotor thrust 40.

[0079] Incidentally, as shown in Figure 5, in cyclic pitch control, the pitch angle θp of the rotor blade 16 is changed moment by moment. Therefore, the rotor blade 16 cannot operate while maintaining the steering angle (reference angle) that maximizes its performance. Thus, if the amount of control of the pitch angle θp in cyclic pitch control can be reduced, the performance of the main rotor 15 can be further enhanced.

[0080] [Moment generated by the thrusters of a compound helicopter] The inventors of the present invention investigated a method to reduce the amount of control required for the pitch angle θp in cyclic pitch control. This method involves using the moments generated by each thruster mounted on the composite helicopter 100 to generate a moment that acts in a direction that counteracts the rolling moment 17M. This can be described as a method to reduce the burden on cyclic pitch control by using the moments generated by each thruster.

[0081] For example, the larger the total amount of moment in the opposite direction to the rolling moment 17M, the more the aircraft's attitude can be maintained even with a large rolling moment 17M. This means that the allowable rolling moment 17M increases, and the burden on cyclic pitch control is reduced. In other words, the larger the rolling moment 17M can be, the less control is needed for the pitch angle θp, and the more the performance of the main rotor 15 can be extracted.

[0082] As described above, the rotational direction of the rolling moment 17M when the fuselage 10 is viewed from the front (second rotational direction) is the opposite direction to the rotational direction 14 (first rotational direction) of the main rotor 15 when the fuselage 10 is viewed from above (see Figures 2 and 3). Therefore, in order to cancel out the rolling moment 17M, it is sufficient to generate a moment that has the same first rotational direction as the main rotor 15 when the fuselage 10 is viewed from the front.

[0083] As explained with reference to Figure 1, in this embodiment, the rotation direction 24A of the forward propeller 22A and the rotation direction 24R of the reverse propeller 22R, the thrust direction 26A of the forward thruster 20A and the thrust direction 26R of the reverse thruster 20R, and the rotation direction 24T of the rear propeller 31 are configured to generate a first rotational moment when viewed from the front of the fuselage 10. This is a rotational direction that can cancel out the rolling moment 17M generated by the main rotor 15.

[0084] Thus, in the composite helicopter 100, by appropriately setting the rotation direction and thrust direction of each thruster, it is possible to increase the total amount of counter-moment that can cancel out the rolling moment 17M. By increasing the total amount of counter-moment, for example, the amount of rolling moment 17M that can be allowed to maintain the aircraft's attitude increases. From another perspective, even if the rolling moment 17M generated by the main rotor 15 is large, it becomes possible to maintain the aircraft's attitude. This makes it possible to reduce the amount of control required for the pitch angle θp, and as a result, the main rotor 15 can be operated more efficiently.

[0085] Figure 6 is a schematic diagram showing the relationship of moments in a composite helicopter presented as a comparative example. Figure 7 is a schematic diagram showing the relationship of moments in the composite helicopter according to this embodiment. Below, the effects of the moments generated by each thruster will be explained by comparing the composite helicopter 90 of the comparative example shown in Figure 6 with the composite helicopter 100 of this embodiment shown in Figure 7.

[0086] In Figures 6 and 7, the rotation direction 14 of the main rotor 15 is assumed to be counterclockwise when viewed from above the fuselage 10. Furthermore, both the composite helicopter 90 and the composite helicopter 100 are assumed to be in forward flight, and cyclic pitch control is being performed on the main rotor 15.

[0087] Figure 6A is a front view of the fuselage 10 of the composite helicopter 90, viewed from the front along the X direction. The composite helicopter 90 is, for example, a composite helicopter to which a conventional configuration is applied, and like the composite helicopter 100 according to this embodiment, it has a main rotor 15, a pair of side thrusters 20 (side propellers 22), and a rear thruster 30 (rear propeller 31). On the other hand, unlike the composite helicopter 100 according to this embodiment, the composite helicopter 90 has the rotation directions of each side propeller 22 in opposite directions, and each thrust direction (direction of the rotation axis of the side propeller 22) is set parallel to the X direction (forward direction 12).

[0088] The forward thrusters 20A, the reverse thrusters 20R, and the rear thruster 30 generate rolling moments 17A, 17R, and 17T, respectively. In the composite helicopter 90, since each side thruster 20 is not tilted with respect to the X direction, the propeller torque 18A directly becomes the rolling moment 17A, and the propeller torque 18R directly becomes the rolling moment 17R. Also, the rolling moment 17T of the rear thruster 30 is the propeller torque 18T. Below, the magnitudes of the propeller torques 18A, 18R, and 18T are given as M. AS M RS , and M TP It should be written as follows.

[0089] Furthermore, the main rotor 15, which is subjected to cyclic pitch control, generates a rolling moment 17M. In the example shown in Figure 6A, since the main rotor 15 rotates counterclockwise when viewed from above, the rolling moment 17M is a clockwise moment when viewed from the front.

[0090] Below, the magnitude of the rolling moment 17M is given by M. MR It states that the rotor thrust of 40 is T MR It states, T MR The distance from the point of application to the center of the main rotor 15 (the amount of displacement of the rotor thrust 40) is denoted as L0. In this case, the magnitude of the rolling moment 17M is M. MR It can be expressed by the following formula. M MR =T MR ×L0 ···(1)

[0091] As shown in Figure 6A, in a conventional composite helicopter 90, the left and right side propellers 22 rotate in opposite directions. This setting is intended to balance the torque of the left and right side propellers 22 by, for example, canceling out the moments generated by each side propeller 22. Furthermore, the rotation direction of the side propellers 22 provided on the main wing section 11 was generally set to follow the wingtip vortices generated at the wingtips of the main wing section 11. In this case, the rotation direction is set so that the side propellers 22 move upward on the main wing section 11 side. When this rotation direction is adopted, as a result, the rotation directions of the left and right side propellers 22 are opposite. For this reason, the rotation direction 24A of the forward propeller 22A (starboard side propeller 22) is set counterclockwise, and the rotation direction 24R of the backward propeller 22R (port side propeller 22) is set clockwise.

[0092] Furthermore, as shown in Figure 6A, in the composite helicopter 90, the rotation direction 24T of the rear propeller 31 is set to clockwise. This is the rotation direction set, for example, to counteract the rolling moment 17M.

[0093] Figure 6B schematically illustrates the relationship between the rolling moments generated by the main rotor 15, forward thruster 20A, reverse thruster 20R, and rear thruster 30 of the composite helicopter 90 using a bar graph. Here, the area above the reference line, shown by the thick solid line, represents a clockwise moment, and the area below represents a counterclockwise moment. The length of the bar graph represents the magnitude of each moment.

[0094] To maintain the aircraft's attitude, for example, the rolling moment 17M generated by the main rotor 15 must be equal to the sum of the rolling moments generated by each thruster (the sum of the moments enclosed by the dotted line in Figure 6B). The sum of the rolling moments generated by each thruster is the sum of the moments taking into account the rotational direction of each moment, but as a whole, it forms an anti-moment that cancels out the rolling moment 17M.

[0095] In the composite helicopter 90, the rolling moment 17M generated by the main rotor 15 is clockwise. The rolling moment 17A generated by the forward thruster 20A is also clockwise, the same as the rolling moment 17M, and does not act as an anti-moment. On the other hand, the rolling moment 17R generated by the reverse thruster 20R and the rolling moment 17T generated by the rear thruster 30 are both counterclockwise, in the opposite direction to the rolling moment 17M, and function as anti-moments. Therefore, the balance of each moment in the composite helicopter 90 is expressed by the following equation. M MR +M AS =M RS +M TP ...(2)

[0096] In equation (2), the left side is the sum of the clockwise rolling moments, and the right side is the sum of the counterclockwise rolling moments (antimoments).

[0097] As shown in Figure 6B, the rolling moment 17A (propeller torque 18A) and the rolling moment 17R (propeller torque 18R) are set to cancel each other out, so although their rotational directions are opposite, their magnitudes are approximately the same (M AS ≒M RS Therefore, the relationship of moments in the compound helicopter 90 can be expressed in practical terms by the following equation. M MR =M TP ...(3)

[0098] Thus, in the composite helicopter 90, the forward propeller 22A and the backward propeller 22R are set to rotate in opposite directions, and neither propeller (in this case, the forward propeller 22A) plays a role in canceling out the rolling moment 17M generated by the main rotor 15. Furthermore, since the rolling moments 17A and 17R cancel each other out, it is essentially necessary to offset the rolling moment 17M with only the rolling moment 17T of the rear thruster 30. In other words, cyclic pitch control is necessary until the rolling moment 17M becomes equal in magnitude to the rolling moment 17T. For this reason, in the composite helicopter 90, the allowable rolling moment 17M is small, and the amount of control for the pitch angle θp must be set to be large in order to maintain attitude.

[0099] Next, with reference to Figure 7, the relationship of moments in the composite helicopter 100 of this embodiment will be explained. As shown in Figure 7A, in the composite helicopter 100, the rotation direction of the forward propeller 22A and the reverse propeller 22R, as viewed from the front, is set to be opposite to the rotation direction 14 (first rotation direction) of the main rotor 15 as viewed from above (second rotation direction). Here, since the first rotation direction is counterclockwise, the rotation direction of the forward propeller 22A and the reverse propeller 22R is set to be clockwise when viewed from the front. Therefore, the rotation of the forward propeller 22A and the reverse propeller 22R generates counterclockwise propeller torques 18A and 18R.

[0100] Thus, in this embodiment, the rotation directions of the side propellers 22, which are generally set alternately on the left and right, are unified on both sides so that they are in the opposite direction to the rotation direction 14 of the main rotor 15 as viewed from above. As a result, propeller torque (propeller torque 18A and propeller torque 18R) in the opposite direction to the rolling moment 17M is applied to the fuselage 10 from both of the two side propellers 22.

[0101] Furthermore, in the rear thruster 30 mounted on the composite helicopter 100, the rotation direction 24T of the rear propeller 31 is set to be opposite to the rotation direction 14 (first rotation direction) of the main rotor 15 as viewed from above (second rotation direction). Therefore, as the rear propeller 31 rotates, a propeller torque (counterclockwise propeller torque 18T) opposite to the rolling moment 17M is applied to the fuselage 10.

[0102] Thus, in the composite helicopter 100 according to this embodiment, the rotation direction of the propellers of all mounted thrusters is set to be opposite to the rotation direction 14 of the main rotor 15. With this setting, the propeller torque (propeller torque 18A, propeller torque 18R, and propeller torque 18T) generated by all propellers (forward propeller 22A, backward propeller 22R, and rear propeller 31) acts in a direction that cancels out the rolling moment 17M generated by the main rotor 15.

[0103] Furthermore, as explained with reference to Figures 1B and 1C, in the composite helicopter 100, the thrust direction of each side thruster 20 (the rotation axis of the side propeller 22) is set to be inclined with respect to the forward direction 12 (X direction) of the composite helicopter 100.

[0104] Specifically, the thrust direction 26R of the reversing thruster 20R (the rotation axis CsR of the reversing propeller 22R) is set to point upward relative to the forward direction 12. As a result, the reversing thruster 20R exerts an upward force Fz not only forward but also upward. RS This can generate a force Fz. In addition, the thrust direction 26A of the forward thruster 20A (the rotation axis CsA of the forward propeller 22A) is set to point downward with respect to the forward direction 12. As a result, the forward thruster 20A generates a force Fz not only forward but also downward. AS It can generate this.

[0105] As shown in Figure 7A, an upward force Fz acts on the retracting side. RS and a downward force Fz acting on the forward side ASThis, when multiplied by the wing span (Ispan), generates thrust moments 19R and 19A. Here, the wing span (Ispan) span This is the length from the center position of the fuselage section 10 in the left-right direction (Y direction) to the position where each thruster is installed. Note that the main wing span I span Typically, the same value is set on both the left and right sides.

[0106] For example, the thrust moment 19R generated in the reverse direction is Fz RS ×I span This is the result. Also, the thrust moment 19A generated on the forward side is Fz AS ×I span This is how it works. The vertical force Fz from the left and right side propellers 22 RS and Fz AS The main wing span is I span This is used as the moment arm length to generate a rolling moment (thrust moment 19R and thrust moment 19A) acting on the aircraft. Both thrust moment 19R and thrust moment 19A are moments with the rotation direction 14 of the main rotor 15 (counterclockwise in this case), and they act in a direction that cancels out the rolling moment 17M generated by the main rotor 15.

[0107] Here, we will explain the inclination angle θt of each side thruster 20 (the inclination angle of the rotation axis of the side propeller 22 with respect to the forward direction 12). For example, as shown in Figure 1B, the backward thruster 20R has an axial thrust T RS And from the angle of inclination θt, an upward force Fz RS Fz RS =T RS ×sin(θt), resulting in a forward force Fx RS Fx RS =T RS It becomes ×cos(θt). Also, as shown in Figure 1C, the forward thruster 20A has an axial thrust force T AS And from the angle of inclination θt, a downward force Fz AS Fz AS =T AS ×sin(θt), resulting in a forward force Fx AS Fx AS=T AS It becomes ×cos(θt).

[0108] The magnitude of the inclination angle θt of each side thruster 20 is preferably set to 10° or less. For example, the forward thrust (Fx RS or Fx AS ) is maximum when θt=0° (T RS or T AS However, if the inclination angle θt is made too large, the forward thrust will decrease. If the inclination angle θt is 10° or less, the loss of forward thrust can be kept to less than 2% of the loss when the inclination angle θt = 0°.

[0109] For example, when the axis of rotation is tilted by 5° (θt=5°), the forward thrust becomes 99.6% of the axial thrust, resulting in a loss of about 0.4%, but approximately 9% of the axial thrust can be exerted in the vertical direction. Thus, by tilting the axis of rotation, even with a small deflection (θt), it is possible to generate a large counter-moment that counteracts the rolling moment of 17M. Furthermore, because the deflection is small, the loss of forward thrust can be kept sufficiently small.

[0110] When side propellers 22 are provided on both sides of the aircraft, it is common practice to set the rotation axis of the side propellers 22 to be parallel to the forward direction 12 (X direction) in order to maximize forward thrust, for example. In contrast, in this embodiment, by deliberately tilting the rotation axis of the side propellers 22, it is possible to generate a thrust moment using the thrust of each side thruster 20, thereby canceling out the rolling moment 17M generated by the main rotor 15.

[0111] Figure 7B schematically illustrates the relationship between the rolling moments generated by the main rotor 15, forward thruster 20A, reverse thruster 20R, and rear thruster 30 of the composite helicopter 100 using a bar graph. As shown in Figure 7B, in the composite helicopter 100, the rolling moment 17A generated by the forward thruster 20A, the rolling moment 17R generated by the reverse thruster 20R, and the rolling moment 17T generated by the rear thruster 30 all work in a direction that cancels out the rolling moment 17M generated by the main rotor 15.

[0112] For example, the rolling moment 17T generated by the rear thruster 30 is the propeller torque 18T generated by the rear propeller 31, and functions as an anti-moment, similar to Figure 6B.

[0113] The rolling moment 17A generated by the forward thruster 20A includes the propeller torque 18A and thrust moment 19A in the first rotation direction (counterclockwise), and its magnitude is M AS +Fz AS ×I span This is the result. Compared to Figure 6B, the direction of rotation of the propeller torque 18A is reversed, and a thrust moment 19A is added.

[0114] The rolling moment 17R generated by the reversing thruster 20R includes the propeller torque 18R and thrust moment 19R in the first rotation direction (counterclockwise), and its magnitude is M RS +Fz RS ×I span This is the result. Compared to Figure 6B, this represents a state where a thrust moment of 19R is added to the propeller torque of 18R. Based on the above, the balance of each moment in the composite helicopter 100 can be expressed by the following equation. M MR =M AS +Fz AS ×I span +M RS +Fz RS ×I span +M TP ...(4)

[0115] Therefore, compared to the antimoment in a conventional composite helicopter 90 (the right-hand side of equation (3) above), for example, the increase in the antimoment in equation (4) is (M AS +Fz AS ×I span +M RS +Fz RS ×I span )

[0116] Thus, in the composite helicopter 100, the rolling moment 17A and rolling moment 17R increase by the amount of the thrust moment 19A and thrust moment 19R, and each functions as an anti-moment without canceling each other out. This makes it possible to significantly increase the total amount of anti-moment. Although the values ​​of the propeller torque 18A and propeller torque 18R may be slightly smaller compared to the case in Figure 6B because the forward thrusters 20A and the reverse thrusters 20R are arranged at an angle, the effect of increasing the total amount of anti-moment remains unchanged because the individual propeller torques do not cancel each other out.

[0117] As the counter-moment increases, the allowable rolling moment 17M increases. Here, L1 is the distance from the point of application of the rotor thrust 40 of the main rotor 15 to the center of the main rotor 15 in the compound helicopter 100. In this case, the magnitude M of the allowable rolling moment 17M in the compound helicopter 100 is MR It can be expressed by the following formula. M MR =T MR ×L1 ···(5)

[0118] Furthermore, the combined helicopter 100 has M MR This allows for a larger value. Therefore, compared to equation (1), L1 > L0, and the point of application of the rotor thrust 40 can be set to a position further away from the center. In other words, the amount of control of the pitch angle θp in cyclic pitch control can be reduced.

[0119] For example, in the conventional composite helicopter 90, the propeller torques 18A and 18R of the side propellers 22 cancel each other out and do not actively play a role in balancing the rolling moment 17M of the main rotor 15. As a result, as shown in Figure 6B, the "sum of the moments generated by each thruster" is relatively small, and it was necessary to rely on cyclic pitch control with a large amount of control to maintain the aircraft's attitude.

[0120] In contrast, in the composite helicopter 100 according to this embodiment, all thrusters can generate an anti-moment that cancels out the rolling moment 17M, and the "sum of the moments generated by each thruster" is larger than that of the composite helicopter 90. As a result, the main rotor 15 can generate a larger rolling moment 17M, which reduces the amount of control required for the pitch angle θp in cyclic pitch control, and consequently contributes to improving the aerodynamic performance of the main rotor 15.

[0121] Figure 8 is a graph showing the control amount of the pitch angle in the composite helicopter of this embodiment. In Figure 8, the solid line graph and the dashed line graph represent the control amount (pitch angle history) of the pitch angle θp of the rotor blade 16 in the conventional composite helicopter 90 and the composite helicopter 100 according to this embodiment, respectively.

[0122] For example, in the compound helicopter 90, the range of change in the pitch angle θp (amplitude of the pitch angle history) is set to be large so that the rolling moment of 17M is relatively small. In contrast, in the compound helicopter 100, since the allowable rolling moment of 17M is large, there is no need to change the pitch angle θp significantly, and the amplitude of the pitch angle history is also small.

[0123] In this way, by reducing the amount of control on the pitch angle θp by cyclic pitch control, it becomes possible to bring the pitch angle θp closer to the reference angle (4° in this case), and it becomes possible to operate the main rotor 15 at a pitch angle θp that is close to constant.

[0124] Figure 9 is a graph showing the relationship between lift offset and main rotor performance. In the graph shown in Figure 9, the horizontal axis represents the lift offset in cyclic pitch control, and the vertical axis represents the relative rotor performance as a percentage, with the lift offset set to 0.

[0125] Lift offset is, for example, the amount of deviation from the center of rotor thrust, and corresponds to the distance L0 in equation (1) and the distance L1 in equation (5) above. Here, the case where the point of application of rotor thrust 40 is the center of the main rotor 15 is set to 0, and the case where it is the tip of the rotor blade 16 is set to 1. Rotor performance is expressed relatively as the effective lift-to-drag ratio, which is expressed as the ratio of lift L to effective drag De (L / De) on the rotor blade 16. Here, the effective drag De is a parameter obtained by adding the converted value obtained by converting the power required to rotate the main rotor 15 into the dimension of drag to the drag force acting on the rotor blade 16.

[0126] As explained with reference to Figures 4 and 5, in cyclic pitch control, the larger the control amount of the pitch angle θp, the more the rotor thrust 40 moves towards the center. Therefore, it can be said that the smaller the lift offset, the larger the control amount of the pitch angle θp. Also, the magnitude of the rolling moment 17M is expressed as the product of the rotor thrust 40 and the lift offset. For this reason, it can also be said that the lift offset is a quantity that represents the magnitude of the rolling moment 17M.

[0127] As shown in Figure 9, rotor performance improves as the lift offset increases. For example, compared to a lift offset of 0, setting the lift offset to 10% improves rotor performance by nearly 4%, and setting the lift offset to 20% improves it by nearly 7%. Thus, the larger the lift offset (or rolling moment 17M), that is, the smaller the control amount of the pitch angle θp, the greater the improvement in rotor performance.

[0128] In the composite helicopter 100 according to this embodiment, as described above, even a relatively large rolling moment 17M can be offset by the counter-moment generated by each thruster. In other words, with cyclic pitch control, the lift offset can be set to a relatively large value. In this case, the amount of control of the pitch angle θp becomes smaller, and the pitch angle θp can be maintained within a range of attack angles that are more efficient. This makes it possible to operate the main rotor 15 sufficiently efficiently.

[0129] Figure 10 is a graph showing the relationship between the rolling moment and speed of a compound helicopter. Figure 10 shows the simulation results for the rolling moment (propeller torque 18S, thrust moment 19S, combined moment 42) generated by the left and right side thrusters 20 of the compound helicopter 100, and the rolling moment 17M generated by the main rotor 15, as a function of flight speed.

[0130] The propeller torque 18S (dotted line graph) is the sum of the propeller torques generated by each side propeller 22 when the rotation direction of each side thruster 20 is aligned. The thrust moment 19S (dotted line graph) is the sum of the thrust moments generated by each side thruster 20 when the rotation axis of the forward-facing side propeller 22 is tilted by -5° and the rotation axis of the backward-facing side propeller 22 is tilted by +5°. The combined moment 42 (solid line graph) is the sum of the propeller torque 18S and the thrust moment 19S.

[0131] The rolling moment 17M (shown in the dashed-dotted graph) is the moment generated by the lift offset of the main rotor 15. The propeller torque 18S, thrust moment 19S, and combined moment 42 all act as counter-moments that cancel out the rolling moment 17M.

[0132] The horizontal axis of the graph represents the flight speed [km / h] of the composite helicopter 100. The vertical axis represents the magnitude of the rolling moment. Here, the cruising speed of the composite helicopter 100 is assumed to be 420 km / h, and the target value of the rolling moment 17M generated by the main rotor 15 at this speed is set to 1, thus standardizing each rolling moment.

[0133] In the composite helicopter 100, the main wing section 11 generates lift, so the rotation speed of the main rotor 15 decreases as the flight speed increases. On the other hand, as the wind speed acting on the main rotor 15 increases, the amount of lift offset applied to the main rotor 15 increases. For this reason, the rolling moment 17M does not increase monotonically.

[0134] Furthermore, as the flight speed increases, the thrust of the side propellers 22 increases, so both the propeller torque 18S and the thrust moment 19S increase with flight speed. In other words, while the rotational speed of the side propellers 22 remains constant, by making the pitch angle of the side propellers 22 a large angle with respect to the plane of rotation of the propellers, the thrust increases and the flight speed increases, and the propeller torque 18S also increases. Looking at the breakdown of the counter-moment generated by the side propellers 22 (side thrusters 20), it can be seen that the propeller torque 18S generated by aligning the rotation direction of each side propeller 22 is significant. In addition, although the thrust moment 19S generated by tilting the axis of rotation is smaller than the propeller torque 18S, it is possible to generate a counter-moment of several percent relative to the rolling moment 17M of the main rotor 15.

[0135] The combined moment 42, which is the sum of these counter-moments, is thought to be able to generate a counter-moment of more than 30% of the rolling moment 17M generated by the main rotor 15 at flight speeds of 400 km / h or higher.

[0136] As shown in Figure 10, the anti-moment obtained from the side propeller 22 (side thruster 20) by the present invention can account for a large portion of the rolling moment 17M caused by the lift offset of the main rotor 15. This makes it possible to significantly reduce the amount of control required for the pitch angle θp in cyclic pitch control, enabling more efficient operation of the main rotor.

[0137] In the composite helicopter 100 according to this embodiment, a main rotor 15 is provided on the upper part of the fuselage 10, and on the sides of the fuselage 10, a forward thruster 20A with a forward propeller 22A and a backward thruster 20R with a backward propeller 22R are provided on the forward and backward sides of the main rotor 15, respectively. The main rotor 15 has a variable pitch angle θp and rotates in a first rotational direction when viewed from above the fuselage 10. The rotational direction and thrust direction of each propeller of the forward thruster 20A and the backward thruster 20R are set so that, when viewed from the front of the fuselage 10 during forward flight, they generate a moment in the same first rotational direction as the main rotor 15. As a result, the rolling moment 17M due to the rotation of the main rotor 15 is canceled out, and it becomes possible to reduce the amount of control required for the pitch angle θp of the main rotor 15, for example. As a result, it becomes possible to operate the main rotor 15 efficiently with a simple configuration.

[0138] To avoid rolling caused by the rolling moment 17M generated by the main rotor 15, possible methods include suppressing the generation of the rolling moment 17M itself, or generating a rolling moment (counter-moment) in the opposite direction to the rolling moment 17M generated by the main rotor 15. For example, one method is to use a contra-rotating rotor to cancel out the rolling moment 17M, but this method would make the drive mechanism very complex, potentially increasing costs and compromising maintainability.

[0139] In this embodiment, the rotation direction and thrust direction of the side propellers 22 in a pair of side thrusters 20 (forward thruster 20A and reverse thruster 20R) are set to generate an anti-moment opposite to the rolling moment 17M generated by the main rotor 15. In this way, the composite helicopter 100 can generate an anti-moment that cancels out the rolling moment 17M with a simple configuration by setting the rotation direction and thrust direction.

[0140] This configuration increases the total amount of counter-moment. This makes it possible to reduce the amount of control required for the pitch angle θp in the cyclic pitch control of the main rotor 15 in the composite helicopter 100. Reducing the amount of control required for the pitch angle θp means that the fluctuation of the pitch angle θp per revolution becomes smaller. As a result, the rotor blades 16 can maintain a pitch angle θp that is aerodynamically efficient, and consequently the power consumption of the aircraft is reduced. This makes it possible to realize a fuel-efficient composite helicopter 100 and extend the range of the composite helicopter 100.

[0141] Furthermore, reducing the amount of control required for the pitch angle θp in cyclic pitch control reduces the load on the pitch link that moves the pitch angle θp of the rotor blade 16, thereby extending the lifespan of the steering system. In addition, the increased margin in the control range of the pitch angle θp is expected to have the effect of extending the limits of the aircraft's flight altitude and flight speed, for example.

[0142] <Second Embodiment> A composite helicopter according to a second embodiment of the present invention will now be described. In the following description, parts that are similar to the configuration and operation of the composite helicopter described in the above embodiment will be omitted or simplified.

[0143] Figure 11 is a schematic diagram showing an example of the configuration of a composite helicopter according to the second embodiment. Figure 11A is a perspective view of the composite helicopter 120. Figure 11B is a side view of the composite helicopter 120 seen from the left side. Figure 11C is a front view of the composite helicopter 120 seen from the front. Here, the rotation direction 14 (first rotation direction) of the main rotor 15 as seen from above the fuselage 10 is assumed to be counterclockwise.

[0144] In the composite helicopter 120 according to this embodiment, as shown in Figure 11A, the rotation direction 24A of the forward propeller 22A and the rotation direction 24R of the backward propeller 22R are set to generate a moment in a first rotational direction when viewed from the front of the fuselage 10 during forward flight. Here, both the rotation direction 24A and the rotation direction 24R are set to rotate clockwise.

[0145] As shown in Figure 11B, the thrust direction 26R of the reversing thruster 20R is aligned with the forward direction 12 (X direction). Similarly, the thrust direction 26A of the forward thruster 20A is also aligned with the forward direction 12 (X direction).

[0146] Therefore, the composite helicopter 120 is configured such that, in the composite helicopter 100 described with reference to Figure 1, the thrust direction 26R of the reversing thruster 20R and the thrust direction 26A of the forward thruster 20A are both arranged horizontally without being tilted with respect to the X direction. In this case, since no upward or downward force corresponding to the tilt is generated in each thruster, no thrust moment is generated.

[0147] Thus, even when each thruster is positioned without tilting, by setting the rotation directions 24A and 24R of the forward-facing propeller 22A and the backward-facing propeller 22R to be in the opposite direction (second rotation direction) to the rotation direction 14 (first rotation direction) of the main rotor 15, it becomes possible to generate an anti-moment (propeller torque) that cancels out the rolling moment 17M generated by the main rotor 15.

[0148] In this case, as shown in FIG. 11C, the rolling moment 17A generated by the forward propeller 20A becomes the propeller torque 18A generated by the rotation of the forward propeller 22A. Also, the rolling moment 17R generated by the reverse propeller 20R becomes the propeller torque 18R generated by the rotation of the reverse propeller 22R. Further, the rolling moment 17T generated by the rear propeller 30 becomes the propeller torque 18T generated by the rotation of the rear propeller 31.

[0149] The balance of each moment in the compound helicopter 120 is expressed by the following equation. M MR =M AS +M RS +M TP ···(6)

[0150] For example, when compared with the conventional compound helicopter 90 described with reference to FIG. 6, the increase in the anti-moment in the compound helicopter 120 according to the present embodiment is (M AS +M RS ). Thus, just by aligning the rotation directions of each side propeller 22 in an appropriate direction, it becomes possible to increase the component that cancels out the rolling moment 17M. Thereby, it becomes possible to efficiently operate the main rotor 15 with a simple configuration.

[0151] <Third Embodiment> FIG. 12 is a schematic diagram showing a configuration example of a compound helicopter according to the third embodiment. FIG. 12A is a perspective view of the compound helicopter 130. FIG. 12B is a side view of the compound helicopter 130 seen from the left side. FIG. 12C is a front view of the compound helicopter 130 seen from the front side. Here, it is assumed that the rotation direction 14 (first rotation direction) of the main rotor 15 seen from above the fuselage 10 is counterclockwise.

[0152] In the composite helicopter 130 according to this embodiment, the thrust direction 26A of the forward thruster 20A and the thrust direction 26R of the backward thruster 20R are set to generate a first rotational moment when the fuselage 10 is viewed from the front during forward flight. Specifically, as shown in Figure 12B, the backward thruster 20R is positioned such that the front end of the rotation axis CsR of the backward propeller 22R points upward with respect to the forward direction 12. Similarly, the forward thruster 20A (right-side thruster 20) is positioned such that the front end of the rotation axis CsA of the forward propeller 22A points downward with respect to the forward direction 12.

[0153] Furthermore, the rotation direction 24A of the forward propeller 22A and the rotation direction 24R of the reverse propeller 22R are set in opposite directions. Here, as in Figure 6 above, the rotation direction 24A is set counterclockwise and the rotation direction 24R is set clockwise.

[0154] Therefore, the composite helicopter 130 is configured such that, in the composite helicopter 100 described with reference to Figure 1, the rotation direction 24A of the forward propeller 22A is reversed, and the rotation directions of each side propeller 22 are set alternately. In this case, the forward thruster 20A and the reverse thruster 20R generate mutually canceling clockwise propeller torques 18A and counterclockwise propeller torques 18R.

[0155] Thus, even when the rotation directions of each side propeller 22 are set to opposite directions, by tilting the rotation axis CsR of the reversing propeller 22R and the rotation axis CsA of the advancing propeller 22A upward and downward with respect to the forward direction 12, it is possible to generate an anti-moment that cancels out the rolling moment 17M generated by the main rotor 15.

[0156] In this case, as shown in Figure 12C, the rolling moment 17A generated by the forward thruster 20A is the propeller torque 18A generated by the rotation of the forward propeller 22A and the downward force Fz ASIt includes the propulsion moment 19A generated thereby. Also, the rolling moment 17R generated by the rearward propeller 20R includes the propeller torque 18R generated by the rotation of the rearward propeller 22R and the propulsion moment 19R generated by the upward force Fz RS It includes the propulsion moment 19R generated by the upward force Fz

[0157] The balance of each moment in the compound helicopter 130 is expressed by the following formula M MR +M AS =Fz AS ×I span +M RS +Fz RS ×I span +M TP ···(7)

[0158] Here, the propeller torques 18A and 18R are set to be approximately the same magnitude so as to cancel each other out (M AS ≒M RS ). Therefore, the relationship of the moments in the compound helicopter 130 is substantially expressed by the following formula M MR =Fz AS ×I span +Fz RS ×I span +M TP ···(8)

[0159] For example, compared with the conventional compound helicopter 90 described with reference to FIG. 6, the increase in the anti-moment in the compound helicopter 130 according to the present embodiment is (Fz AS ×I span +Fz RS ×I span) This is how it works. In this way, simply tilting the rotation axis of each side propeller 22 in the appropriate direction makes it possible to increase the component that cancels out the rolling moment 17M. This makes it possible to operate the main rotor 15 efficiently with a simple configuration.

[0160] <Other Embodiments> The present invention is not limited to the embodiments described above, and various other embodiments can be realized.

[0161] In the composite helicopter 100 described above, during forward flight, each side propeller 22 is rotated at a constant rotational speed, and the thrust, propeller torque 18S, and thrust moment 19S are changed by changing the pitch angle of each side propeller 22. However, the thrust, propeller torque 18S, and thrust moment 19S may also be changed by changing the rotational speed of each side propeller 22 in addition to changing the pitch angle. Alternatively, the thrust, propeller torque 18S, and thrust moment 19S may be changed by changing the rotational speed of each side propeller 22 instead of changing the pitch angle.

[0162] In the above embodiment, the thrust direction of both side thrusters, which are provided on the left and right sides of the composite helicopter, is inclined relative to the forward direction. However, it is not limited to this, and the thrust direction of only one of the left or right side thrusters may be inclined. For example, the forward thruster may be inclined so that its front end is tilted upward, and the forward thruster may be inclined so that its front end is tilted downward. In this way, even when either the left or right side thruster is inclined, it is possible to generate a thrust moment in a direction that counteracts the rolling moment generated by the main low.

[0163] In the above embodiment, the case in which the side thruster is a propeller thruster equipped with side propellers was described, but the type of side thruster is not limited. For example, a jet engine may be used as the side thruster. A jet engine is a thruster that generates thrust by rotating a turbine equipped with, for example, a compression fan, and injecting high-pressure, high-temperature combustion gas. In this case, the compression fans of the jet engine mounted on the forward and backward sides of the main rotor correspond to the forward rotor blades and backward rotor blades, respectively. In this case, by setting the rotation direction of each compression fan on the left and right sides as viewed from the front to the first rotation direction, it is possible to cancel out the rolling moment generated by the main rotor.

[0164] Furthermore, when jet engines are used, the thrust direction of the jet engine may be inclined relative to the forward direction. That is, on the receding side of the main rotor, the thrust direction is inclined such that the front end of the jet engine points upward relative to the forward direction. Also, on the receding side of the main rotor, the thrust direction is inclined such that the front end of the jet engine points downward relative to the forward direction. This makes it possible to use the thrust of the jet engine to generate a thrust moment in a direction that counteracts the rolling moment generated by the main rotor.

[0165] Furthermore, the above description assumes that the side thrusters are attached to the wingtips of the main wing section. However, the design is not limited to this configuration; the side thrusters may also be attached to the middle of the main wing section (between the wingtip and the fuselage). Additionally, the side thrusters may be attached to components other than the main wing section. For example, the side thrusters may be supported using support members that do not constitute an airfoil cross-section. In this case, the main wing section may or may not be provided.

[0166] Furthermore, while the above description focused on the case where the rear thruster is a propeller thruster, a jet engine could also be used as the rear thruster. Moreover, a rear thruster is not necessarily required. In this case, for example, a configuration with a pair of side thrusters positioned at the tail of the aircraft is also possible.

[0167] In this way, by applying the present invention, regardless of the presence or absence of main wings or rear thrusters, it is possible to generate an anti-moment that cancels out the rolling moment generated by the main rotor. As a result, the amount of pitch angle control in cyclic pitch control is suppressed, and the main rotor can be operated efficiently.

[0168] It is also possible to combine at least two of the feature features of the present invention described above. In other words, the various feature features described in each embodiment may be combined arbitrarily without distinction between embodiments. Furthermore, the various effects described above are merely examples and are not limiting, and other effects may also be exhibited. [Explanation of symbols]

[0169] 10... Torso 11…Main wing section 12...Forward direction 15…Main rotor 17M…Rolling moment 20A…Forward side thruster 20R…Reverse thruster 22A…Forward-facing propeller 22R... Reverse propeller 30…Rear thruster 31...Rear propeller 100, 120, 130... Compound helicopters

Claims

1. Torso and A main rotor with a variable pitch angle is provided on the upper part of the fuselage and rotates in a predetermined rotational direction when viewed from above the fuselage, A forward-facing thruster having forward-facing rotor blades, which is provided on the side of the fuselage portion on the forward-facing side from which the main rotor moves forward, A reversing thruster having reversing rotor blades, which is provided on the side of the fuselage portion on the reversing side from which the main rotor moves toward the rear, It is equipped with, The forward-moving rotor blade and the backward-moving rotor blade both rotate in the opposite direction to the predetermined rotation direction when viewed from the front of the fuselage during forward flight. A composite helicopter.

2. A composite helicopter according to claim 1, The thrust direction of at least one of the forward thrusters and the reverse thrusters is set to be inclined with respect to the forward direction of the composite helicopter such that a moment in the predetermined rotational direction is generated when the fuselage is viewed from the front. A composite helicopter.

3. A composite helicopter according to claim 2, Both the forward-moving rotor blade and the backward-moving rotor blade are propellers. The forward thruster is positioned such that the front end of the rotation axis of the forward rotor blade points downward with respect to the forward direction. A composite helicopter.

4. A composite helicopter according to claim 2, Both the forward-moving rotor blade and the backward-moving rotor blade are propellers. The retractable thruster is positioned such that the front end of the rotation axis of the retractable rotor blade points upward with respect to the forward direction. A composite helicopter.

5. A composite helicopter according to any one of claims 1 to 4, further, It comprises a pair of main wing sections extending to the left and right from the aforementioned fuselage section, The forward thruster is provided on the forward-facing main wing portion, The retracted thruster is provided on the retracted side of the main wing. A composite helicopter.

6. A composite helicopter according to any one of claims 1 to 4, Both the forward-moving rotor blade and the backward-moving rotor blade are propellers with a variable pitch angle. The forward-facing thruster and the backward-facing thruster rotate their respective rotor blades at a constant rotational speed during forward flight, and change the thrust by changing the pitch angle of each rotor blade. A composite helicopter.

7. A composite helicopter according to any one of claims 1 to 4, further, The system is equipped with a rear thruster having a rear rotor blade located at the rear of the fuselage and rotating in a direction opposite to the predetermined rotation direction when viewed from the front. A composite helicopter.

Images