Hybrid propulsion helicopter comprising primary coaxial counter-rotating rotor and secondary tail rotor

Abstract

A helicopter includes a fuselage having a first yaw axis, a first propulsion unit on the fuselage, a transmission unit in torque transmission connection with the first propulsion unit, first and second counter-rotating main rotors rigidly connected to the transmission unit for rotation, the first yaw axis passing through the transmission unit, the first main rotor and the second main rotor respectively have a first main blade and a second main blade, and when the first main rotor and the second main rotor rotate, the first main blade is configured to have a variable first common incident angle and the second main blade is configured to have a fixed second common incident angle; the helicopter further includes first and second auxiliary rotors rotating about second and third axes, respectively, and a second electric propulsion unit in torque transmission connection with the first and second auxiliary rotors, where the first and second auxiliary rotors are arranged opposite the roll axis of the helicopter and in positions laterally spaced from the pitch axis; the first and second auxiliary rotors are configured to generate first and second aerodynamic forces, respectively, to rotate the helicopter relative to the pitch or roll axis; all the rotors of the helicopter have respective axes that intersect a plane of gravity of the helicopter, including roll and pitch axes, defining vertices of a non-axisymmetric graph.

Description

Technical Field

[0001] This invention relates to the field of helicopters, and more particularly to a hybrid propulsion helicopter comprising a pair of main coaxial counter-rotating rotors and a pair of auxiliary tail rotors. Background Technology

[0002] In the field of helicopters, solutions have been developed over the years to improve the controllability of these aircraft. These solutions focus on reducing the unwanted effects of structural configurations of helicopter components, such as the rotor, and providing greater flexibility for maneuvering during flight. For example, to achieve forward motion and / or lateral translation of the helicopter, a widely used structural solution involves adjusting the rotor blades' incident angle by controlling the periodic pitch (i.e., the periodic change in the blade's angle of incidence during rotation), thereby guiding the horizontal component of the generated aerodynamic force to achieve forward motion and / or lateral translation. However, implementing these adjustments typically requires creating complex configurations involving numerous mechanical components with relative motion, such as a swashplate mounted on the helicopter's driveshaft (to which the rotor blades (or rotor) are connected via linkages, bearings, bushings, etc.). For example, to counteract the undesirable yaw effect present in single-rotor helicopters (i.e., generating a pair of reaction forces opposite to the rotation of the rotor itself, which often causes the helicopter to rotate about its vertical axis, i.e., yaw), solutions commonly involve the use of an auxiliary rotor or anti-torque rotor mounted at the tail of the helicopter to counteract this effect. However, implementing these solutions requires complex transmission systems, such as a drive shaft passing through the tail of the helicopter, to transmit power generated by the helicopter engine to the anti-torque rotor. For example, in some cases, the mechanical power supplied to the anti-torque rotor can be approximately 25% of the power supplied to the main rotor. As an alternative to an auxiliary anti-torque rotor placed at the tail of the helicopter, solutions are also common, involving the use of a pair of counter-rotating and coaxial (or non-coaxial) main rotors to generate a pair of mutually canceling, opposite-sign reaction forces, thereby preventing the helicopter from exhibiting undesirable yaw behavior. Current solutions have complex structural configurations, involving high structural and maintenance costs and high reliability risks.

[0003] It is believed that a simple and compact solution needs to be created to minimize the overall size and associated structural and management costs in order to fully realize the performance and reliability of helicopters. Summary of the Invention

[0004] The present invention has a scope that at least partially satisfies the above-mentioned requirements, wherein such scope is achieved by a helicopter according to claim 1 comprising first and second counter-rotating main rotors and first and second auxiliary tail rotors.

[0005] According to a preferred embodiment of the present invention, a helicopter is provided, comprising a fuselage, a first propulsion unit (preferably a thermal propulsion unit, such as an internal combustion engine or gas turbine) on the fuselage, a transmission unit torque-driven to the first propulsion unit, and first and second counter-rotating main rotors. Furthermore, the first and second main rotors each have a first main blade and a second main blade, wherein, as the main rotors rotate, the first main blade is configured with a common first angle of incidence that varies, while the second main blade has a fixed second angle of incidence. Additionally, all rotors of the helicopter have corresponding axes that truncate the plane of gravity, including the roll and pitch axes, defining a non-axisymmetric figure. This means that the present invention is not applicable to any helicopter (even unmanned helicopters) with an even number of axisymmetrically arranged rotors, such as quadcopters or hexacopters. Rather, the present invention is applicable, for example, to the configuration shown in the figures, where the intersection of the rotor axes with the plane of gravity of the helicopter (including the roll and pitch axes) defines the vertices of a figure (e.g., a triangle, or more generally, a non-axisymmetric figure). For example, in the case of a main rotor with a converging axis and a staggered rotor, such as the case of the K. Max, the axis still intersects the plane of the center of gravity or a plane parallel to the plane of the center of gravity, so it can always be verified that the figure defined by the intersection point is non-axisymmetric.

[0006] Furthermore, it is understood that this feature requires the blades to maintain a fixed angle of incidence, or to be adjusted such that each blade has the same angle of incidence as the others, i.e., adjusted according to the control of the collective pitch of the blades. To achieve the latter, such a helicopter may include a swashplate mounted on the transmission unit to modify the collective pitch of the lower main rotor. Thus, compared to solutions that control the periodic pitch of the blades, such as by using a swashplate oriented relative to the roll and pitch axes, the number of mechanical components is significantly reduced, thereby reducing overall size, weight, and associated structural and maintenance costs, which is beneficial to reliability. In this configuration, the first and second main rotors generate aerodynamic forces (i.e., lift) through the first and second main blades, the horizontal component of which is negligible or zero, thereby vertically taking off and landing the helicopter in flight or keeping the helicopter hovering. Since the horizontal component is essentially negligible or zero, rotation of the first and second main rotors alone is insufficient to move the helicopter forward and / or translate laterally. Therefore, according to the present invention, in order to achieve forward motion and / or lateral translation of the helicopter, first and second auxiliary rotors are provided mounted on corresponding tail booms. The first and second auxiliary rotors are configured to rotate about second and third axes, respectively, preferably parallel to and equidistant from the yaw axis. Specifically, these first and second auxiliary rotors are arranged opposite to the helicopter's roll axis and are laterally spaced relative to the yaw axis. The first and second auxiliary rotors have first and second auxiliary blades configured to generate aerodynamic forces capable of rotating the helicopter about a pitch axis or a roll axis. Specifically, a first angular momentum and a second angular momentum are generated by aerodynamic arms parallel to the yaw axis generated by the first and second auxiliary blades in two directions relative to the yaw axis. The first angular momentum causes the helicopter to rotate relative to the pitch axis, and the second angular momentum causes the helicopter to rotate about the roll axis. To generate the first or second angular momentum, it is necessary to adjust the rotational intensity and direction of the first and second auxiliary rotor blades. To achieve rotation of the first and second auxiliary rotors, the helicopter also includes a second electric propulsion unit (e.g., an electric motor connected to each auxiliary rotor) connected in a torque-driven manner to the first and second auxiliary rotors. Therefore, the rotation of the helicopter relative to its pitch or roll axis causes rigid rotation of the drive shaft and the first and second main rotors. The aerodynamic forces generated by the rotation of the first and second main rotors thus have a horizontal and controlled desired component, enabling the helicopter to move forward, backward, and laterally according to its tilt. Therefore, the main rotors can be understood as generating the aerodynamic forces for vertical takeoff / desktop or for maintaining hovering flight. On the other hand, the auxiliary rotor generates the aerodynamic forces required to rotate the helicopter relative to a desired axis during flight. Therefore, its lift contribution is negligible compared to the main rotors, and thus the auxiliary rotor is smaller in size compared to the main rotors.In this way, maneuverability (e.g., forward movement and / or lateral translation) is achieved, comparable to that obtained by a swashplate on a helicopter conventionally controlled by periodic pitch adjustments of the first and second main rotor blades. Structurally, this provides a simplified, compact solution with significantly reduced costs. Furthermore, since the auxiliary rotor is driven by an electric motor (e.g., powered by the helicopter's generator and battery unit), a complex mechanical power transmission system can be replaced with simple wiring, thus benefiting the helicopter's overall weight and reliability. This configuration can be applied to both remotely piloted and manned helicopters. Attached Figure Description

[0007] The structural and functional characteristics of the helicopter can be better understood from the following detailed description, with reference to the accompanying drawings, which illustrate preferred and non-limiting embodiments, wherein:

[0008] Figure 1 A schematic diagram of a preferred embodiment of the present invention is shown;

[0009] Figure 2 A schematic diagram illustrating the adjustment of the longitudinal movement (forward / backward) of a helicopter according to a preferred embodiment is shown;

[0010] Figures 3a-3b A schematic diagram of the adjustment of the lateral translation of a helicopter according to a first preferred embodiment is shown;

[0011] Figure 4 A schematic diagram of a helicopter flight control device according to a first embodiment is shown. Detailed Implementation

[0012] According to a preferred but non-limiting embodiment of the present invention, Figure 1A schematic diagram of a remotely controlled helicopter E (also known as a UAS (Unmanned Aerial System) or UAV (Unmanned Aerial Vehicle)) is shown, having a roll axis X, a pitch axis Y, and a first axis A (i.e., a yaw axis). The helicopter includes a fuselage C, a propulsion unit 1 (preferably thermodynamically related, such as an internal combustion engine or gas turbine) on the fuselage, and a transmission unit 2 (the transmission unit 2 extends parallel to the first axis A and is torque-driven to the propulsion unit 1). The helicopter E also includes a first main rotor 3 and a second main rotor 4, which are rotationally rigidly connected to the transmission unit 2 relative to the first axis A. Furthermore, the first and second main rotors 3 and 4 are coaxial and have first and second main blades 3a and 4a extending laterally along axis A, respectively, such that when the transmission unit rotates, the first and second main blades generate aerodynamic forces, thereby generating lift that enables the helicopter to ascend and descend vertically, for example, to perform takeoff and landing, but also to hover in flight. Specifically, to generate this lift, propulsion unit 1 produces mechanical power, which is used and transmitted (i.e., through transmission unit 2) to rotate the first and second main rotors 3, 4. Furthermore, the first and second main rotors 3, 4 rotate in opposite directions; for example, when the second main rotor 4 rotates clockwise, the first main rotor 3 is configured to rotate counterclockwise, and vice versa. This feature is used to counteract the effects of unwanted yaw (i.e., the helicopter's rotation about axis A). If the helicopter included only one main rotor connected to transmission unit 2, a pair of reaction forces opposite to the rotor's rotation would be generated by just one main rotor, which would tend to cause the helicopter's fuselage 1 to rotate about axis A. However, by using two counter-rotating rotors, the two pairs of reaction forces opposite to each rotor's rotation cancel each other out, thus keeping the helicopter stable. This avoids the need for an auxiliary rotor (also called an "anti-torque rotor"), which is typically mounted at the tail of the helicopter to counteract the unwanted yaw effect caused by the rotation of only one main rotor. According to one aspect of the invention, in order to reduce the structural complexity of the helicopter without compromising performance, thereby optimizing structural cost and reliability, the first main rotor blade 3a is configured to have a predetermined common first angle of incidence, and the second main rotor blade 4a is configured to have a predetermined second common angle of incidence, when the first and second main rotors rotate. Therefore, this configuration requires that the angles of incidence of the blades remain fixed, or be adjusted such that each blade has an angle of incidence equal to that of the other blades, i.e., adjusted according to control of the collective pitch of the blades. To achieve the latter, the helicopter may include a swashplate oriented relative to the roll and pitch axes, the swashplate being mounted on a transmission unit and rigidly connected to the main rotor blades. For example, the swashplate may include an adjustment device by which the angles of incidence of the blades can be adjusted according to a predetermined angle common to all blades.Preferably, a swashplate is connected to the first lower main rotor 3, and the swashplate is configured to adjust the collective pitch of the first main rotor blade 3a, while the second main rotor 4 has a second main rotor blade 4a with a fixed pitch (i.e., not adjustable by the swashplate). In both cases, the lift generated by the rotation of the first and second main rotors 3, 4 will cause the helicopter to move vertically, i.e., the horizontal component of the aerodynamic force generated by the main rotors can be ignored or zero, so the helicopter will not move forward / backward or laterally. Furthermore, since lift is a function of the angular velocity of the first and second main rotors, the change in the revolutions of the propulsion unit 1 determines the change in lift. According to the invention, in order to achieve forward motion and / or lateral translation in flight, the helicopter includes first and second auxiliary tail rotors 5, 6, which are arranged in a relative manner with respect to the roll axis X and longitudinally spaced from the yaw axis A. These first and second auxiliary rotors are configured to rotate about second and third axes B1, B2 (preferably parallel to axis A), respectively. Preferably, these first and first auxiliary rotors 5, 6 are symmetrical with respect to the roll axis X. Furthermore, the first and second auxiliary rotors 5 and 6 each have first and second auxiliary blades 5a and 6a, which extend laterally relative to the second and third axes B1 and B2, respectively, to generate aerodynamic forces parallel to the second and third axes B1 and B2 when the first and second auxiliary rotors 5 and 6 rotate. The helicopter E includes first and second tail sections 7 and 8, each tail section extending laterally from the helicopter fuselage C relative to axis A in a divergent manner according to a predetermined angle. According to this configuration, the first and second tail sections 7 and 8 each have a first end E1 connected to the fuselage and a second end E2 opposite to the first end, wherein the first auxiliary rotor 5 is arranged on one of the second ends E2, and the second auxiliary rotor 6 is arranged on the other of the second ends E2. According to another aspect of the invention, in order to actuate the rotation of the first and second auxiliary rotors 5, 6, the helicopter E includes a second propulsion unit comprising a first electric motor 10a and a second electric motor 10b, wherein the first electric motor 10a is disposed on one of the second ends E2 and connected to the first auxiliary rotor 5, and the second electric motor 10b is disposed on the other of the second ends E2 and connected to the second auxiliary rotor 6. The second propulsion unit also includes a conversion device 11 (e.g., an alternator) for converting mechanical energy into electrical energy, which is disposed on the fuselage 1 and connected to the first propulsion unit 1 at the torque transmission input and to the first and second electric motors 10a, 10b at the output, thereby converting mechanical energy from the first propulsion unit 1 into electrical energy to power the electric motors 10a, 10b, for example, through connecting cables passing through the first and second tail sections 7, 8.Preferably, the second propulsion unit includes an electrical energy storage device 12 (e.g., a lithium-ion battery), which is preferably arranged on the fuselage 1 and electrically connected at its input end to a mechanical energy-to-electrical energy conversion device 11 to store the electrical energy provided by the mechanical energy-to-electrical energy conversion device 11, and electrically connected at its output end to electric motors 10a and 10b. According to this structural scheme, the positions of the first and second auxiliary rotors 5 and 6 can be used to actuate and control the forward movement and lateral translation of the helicopter in flight, i.e., the rotation of the fuselage 1 relative to the pitch axis Y and the roll axis X. Figure 2 As shown, when the blades of the first and second auxiliary rotors 5 and 6 rotate, the first auxiliary rotor 5 generates a first aerodynamic force F1 aligned with the second axis B1, while the second auxiliary rotor 6 generates a second aerodynamic force F2 parallel to the third axis B2. These first and second aerodynamic forces F1 and F2, when multiplied by their respective longitudinal distances (i.e., the arms of each force) relative to the pitch axis Y and roll axis X, generate a first angular momentum M1 and a second angular momentum M2, respectively. The first angular momentum causes the helicopter fuselage 1 to rotate about the pitch axis Y, and the second angular momentum causes the fuselage 1 to rotate about the roll axis X. For this purpose, the mechanical and electrical power delivered by the first and second propulsion units to the main rotors 3 and 4 and the auxiliary rotors 5 and 6 can be adjusted. Figure 2 As shown, after the helicopter takes off, for example, to adjust longitudinal motion (e.g., forward movement parallel to the roll axis X), the first and second auxiliary rotors 5 and 6 are driven by motors 10a and 10b so that the first and second auxiliary blades 5a and 6a have the same direction of rotation, thereby generating aerodynamic forces F1 and F2 respectively that cause a first angular momentum M1. This first angular momentum M1 causes the front end of the helicopter opposite to the first and second auxiliary rotors to tilt towards the ground relative to the pitch axis Y. In this way, the first angular momentum M1 causes the helicopter fuselage 1 and the main rotor to rotate rigidly relative to the Y-axis, thereby generating aerodynamic forces on the main blades 3a and 4a. The horizontal component of the aerodynamic forces is no longer negligible or zero, thus actuating the helicopter forward. This produces the effect obtained by adjusting the periodic pitch of the blades 3a and 4a by, for example, using a swashplate that can be oriented relative to the X and Y axes. Similarly, by reversing the rotation directions of the first and second auxiliary rotors 5 and 6, aerodynamic forces F1 and F2 are generated in the opposite direction to the previous case. This causes the angular momentum M1 to raise the helicopter relative to the pitch axis Y relative to the ground and the rear end opposite to the first and second auxiliary rotors. Therefore, the horizontal component of the aerodynamic force generated by the main rotor blades 3a and 4a causes the helicopter to decelerate and move forward or backward from its hovering position in flight. To adjust the lateral translation of the helicopter, such as the helicopter's rotation about the X-axis, ... Figures 3a-3bAs shown, the first and second auxiliary rotors 5 and 6 are actuated so that the auxiliary blades 5a and 6a have opposite or the same direction of rotation but different rotational speeds, thereby generating a resultant force on a single arm, such as generating opposite or the same aerodynamic forces F1 and F2 with different moduli. In both cases, the aerodynamic forces F1 and F2 generate a second angular momentum M2, which causes the helicopter fuselage and main rotor to rotate rigidly relative to the pitch axis, such that the horizontal component of the aerodynamic force generated by the main blades 3a and 4a is not negligible or is not zero, thereby causing lateral translation of the helicopter while it is stationary or moving forward or backward. In this case, the effect obtained by adjusting the periodic pitch of the main blades 3a and 4a, for example, using a swashplate that can be oriented relative to the X and Y axes, is also produced. Preferably, this structural solution can also be extended to helicopters with pilots on board. Preferably, in order to obtain these operating conditions, such as Figure 4 As shown, the helicopter E may include a control module 13 on board, which includes an antenna 14 and an electronic control unit 15 connected to a ground-based transceiver device 16 (e.g., a portable control device) for data exchange. Furthermore, the electronic control unit 15 is designed to receive signals from the transceiver device containing information about the rotational speeds of the first and second main rotors 5, 6, set by a user on the ground, for example, using the control device, to adjust the helicopter's vertical motion. Additionally, the control unit is designed to receive signals from the transceiver device containing information about the rotational speeds of the first and second auxiliary rotors 5, 6, set by the user, thereby adjusting the helicopter's longitudinal and / or lateral translation while the first and second main rotors 5, 6 are rotating.

Claims

1. A helicopter (E), wherein, The helicopter (E) includes a fuselage (C) having a first yaw axis (A), a first propulsion unit (1) located on the fuselage, a transmission unit (2) connected to the first propulsion unit in a torque transmission manner, and a first counter-rotating main rotor and a second counter-rotating main rotor (3, 4) rigidly connected to the transmission unit (2) for rotation. The first yaw axis (A) passes through the transmission unit (2), and the first counter-rotating main rotor and the second counter-rotating main rotor (3, 4) respectively have a first main rotor blade and a second main rotor blade (3a, 4a). When the first and second main rotors rotate, the first main rotor blade is configured to have a varying first common angle of incidence (C1), and the second main rotor blade is configured to have a fixed second common angle of incidence (C2). The helicopter (E) also includes a second axis and a second main rotor blade. A first auxiliary rotor and a second auxiliary rotor (5, 6) rotating on a third axis (B1, B2), and a second electric propulsion unit connected to the first auxiliary rotor and the second auxiliary rotor (5, 6) in a torque-driven manner, wherein the first auxiliary rotor and the second auxiliary rotor are arranged opposite to the roll axis (X) of the helicopter and are laterally spaced relative to the pitch axis (Y), such that the first auxiliary rotor and the second auxiliary rotor (5, 6) are configured to generate a first aerodynamic force and a second aerodynamic force (F1, F2) respectively to rotate the helicopter relative to the pitch axis (Y) or the roll axis (X); all rotors of the helicopter (E) have corresponding axes that intersect the plane of the center of gravity of the helicopter (E) including the roll axis and the pitch axis, defining the vertices of a non-axisymmetric figure.

2. The helicopter (E) according to claim 1, wherein, The second electric propulsion unit includes a first electric motor and a second electric motor (10a, 10b) and a mechanical energy to electrical energy conversion device (11). The first electric motor and the second electric motor (10a, 10b) are respectively connected to the first auxiliary rotor and the second auxiliary rotor (5, 6). The mechanical energy to electrical energy conversion device (11) is connected to the first propulsion unit (1) at the input and to the first electric motor and the second electric motor (10b, 10a) at the output to convert the mechanical energy generated by the first propulsion unit (1) into electrical energy to be supplied to the first electric motor and the second electric motor.

3. The helicopter (E) according to claim 2, wherein, The helicopter includes a first tail section and a second tail section (7, 8), each tail section extending laterally from the fuselage of the helicopter in a divergent manner relative to the first yaw axis (A) at a predetermined angle. The first tail section and the second tail section each have a first end (E1) connected to the fuselage and a second end (E2) opposite to the first end, wherein the first auxiliary rotor (5) is arranged on one of the second ends, and the second auxiliary rotor (6) is arranged on the other of the second ends.

4. The helicopter (E) according to any of the preceding claims, wherein the helicopter (E) includes a vibrating plate rigidly connected to the transmission unit (2) and the first main rotor blade (3a), and further includes a vibrating plate adjustment device configured to adjust the incident angle of the first main rotor blade (3a) via the collective pitch control.

5. The helicopter (E) according to any of the preceding claims, wherein the helicopter (E) includes an onboard control module (13), the control module (13) including an antenna (14) and an electronic control unit (15) connected to a transceiver device (16) available to a user on the ground for data exchange, the electronic control unit being designed to: a. Receive a signal containing information about the rotational speeds of the user-defined first and second main rotors (3, 4) to drive the vertical movement of the helicopter; and b. Receive a signal containing information about the rotational speeds of the first auxiliary rotor and the second auxiliary rotor (5, 6) to drive the longitudinal movement and / or turning of the helicopter while the first main rotor and the second main rotor (3, 4) are rotating.

6. The helicopter according to any of the preceding claims, wherein, The maximum power of the second electric propulsion unit is lower than or equal to the maximum power of the first propulsion unit (1). Preferably, the first propulsion unit is a first internal combustion engine propulsion unit.

7. The helicopter according to any of the preceding claims, wherein, The helicopter in question is an unmanned aerial vehicle (UAV).

8. The helicopter according to any of the preceding claims, wherein, Apart from the opposing rotation axes of the first and second main rotors, the second shaft and the third shaft (B1, B2) are the only shafts on the helicopter (E).

9. The helicopter according to any of the preceding claims, wherein, The rotation axes of the first counter-rotating main rotor and the second counter-rotating main rotor coincide with the first axis (A), and wherein the first yaw axis, the second axis, and the third axis (A, B1, B2) are parallel to each other.

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