Arrangement for periodic rotor

Abstract

The rotor assembly includes a rotor mast, a motor, and a rotor hub. The rotor mast may be connected to the motor and the rotor hub. The rotor mast is rotatable about a first axis. A plurality of blades may be connected to the rotor hub. The rotor hub may include a shaft that may connect blades. A swash plate may be connected to the rotor mast and the shaft. A single linkage may extend from a first end to a second end, the first end may be coupled to the shaft and the second end may be coupled to the swash plate. A single linkage may be configured to translate movement of the swash plate into rotation of the shaft about the second axis, thereby simultaneously rotating the blades about the second axis.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 479,967, filed on January 13, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0003] The present disclosure relates to a rotor system for a vertical take-off and landing aircraft. In particular, the present disclosure relates to a rotor assembly incorporated into a vertical take-off and landing aircraft. Background Art

[0004] Various aircraft, including airplanes (e.g., air transportation aircraft), use rotors or propellers to generate thrust and propel the aircraft. Air transportation involves using aircraft to carry out commuting activities that were traditionally completed by car. Air transportation is considered an effective means of transportation to address traffic congestion and reduce environmental pollution in areas with high automobile usage, such as cities.

[0005] Modern air mobility vehicles (AMVs) and other types of aircraft are highly complex. These vehicles employ multi-level integrated computing systems to control complex electromechanical devices and sophisticated components to automate various aircraft functions and assist the pilot during flight. For example, electric vertical take-off and landing (eVTOL) aircraft, which can be used as AMVs, employ distributed propulsion systems (DEPs) that include multiple rotor assemblies and various types of rotor assemblies (e.g., tilt, non-tilt, propeller rotors, or lift rotors).

[0006] A propeller rotor may refer to a rotary airfoil that can function as both an airplane-style propeller and a helicopter-style rotor. For example, aircraft may include the general categories of horizontal thrust aircraft (e.g., fixed-wing aircraft) and vertical thrust aircraft (e.g., helicopters), or a combination of the two (e.g., "vertical take-off and landing" or "VTOL"). Aircraft utilizing propellers or propeller rotors use a rotor hub to control and transfer power to the propeller rotors.

[0007] Different types of rotors and propellers present different challenges and advantages. For example, some rotor assembly systems have a hub assembly that includes a pitch rocker arm for each blade. The pitch rocker arm is connected to a corresponding swashplate of the rotor assembly to control each individual blade. Having a pitch rocker arm on each blade puts additional stress on the hub assembly and can create drag, increase vibration, and add weight. Furthermore, using a separate pitch rocker arm for each blade can result in less accurate blade adjustment during cyclical movements of the rotor assembly.

[0008] Some conventional rotor assemblies can also present problems when used in AMVs or other aircraft with multiple rotor assemblies. For example, some hubs have difficulty adapting to lift variations between the aircraft's different rotors. This can cause vibrations and increase mechanical stress, potentially shortening the aircraft's service life or incurring additional maintenance costs.

[0009] Therefore, there is a need for an efficient, scalable, safe, easily manufactured, and economically viable rotor assembly for a vertical take-off and landing vehicle suitable for efficiently generating horizontal thrust capability at high speeds and taking off and landing with minimal infrastructure requirements. There is also a need for a rotor assembly with a minimum number of parts to reduce drag, weight, and mechanical stress.

[0010] Therefore, the present disclosure relates to rotor assemblies that can be incorporated into AMVs, such as eVTOLs. The background description provided herein is intended to generally present the context of the present disclosure. Unless otherwise indicated herein, the materials described in this section are not prior art to the claims in this application and are not admitted to be prior art or suggestions of prior art by virtue of their inclusion in this section. Summary of the Invention

[0011] Examples described herein include apparatus, systems, and methods for a rotor assembly. The rotor assembly may include one or more of the following features: a rotor mast connected to a motor and a rotor hub, the rotor mast rotatable about a first axis; a plurality of blades connected to the rotor hub; the rotor hub including a shaft connected to the blades, the shaft rotatable about a second axis; a swash plate connected to the rotor mast and the shaft; and a single linkage extending from a first end to a second end, the first end coupled to the shaft and the second end coupled to the swash plate, the single linkage configured to convert motion of the swash plate into rotation of the shaft about the second axis, thereby simultaneously rotating the plurality of blades about the second axis.

[0012] Various aspects of exemplary devices, systems, and methods according to the present disclosure may include one or more of the following features: the first end of the single linkage is formed on a pitch link, and the second end of the linkage is formed on a control rod; the pitch link is coupled to the shaft at the most central point of the shaft; the first end of the pitch link is generally cylindrical and includes a hole configured to receive the shaft, wherein the first end of the pitch link forms the first end of the linkage; a second end of the pitch link opposite the first end of the pitch link is coupled to the control rod, the second end of the pitch link being configured to pivot when raised or lowered by the control rod; the shaft is configured to simultaneously reduce a first angle of attack of a first blade and increase a second angle of attack of a second blade. The rotor assembly may also include a first actuator and a second actuator, each configured to move the swash plate; and the shaft is connected to the rotor mast via two yoke-shaped projections, with the first end of the linkage being disposed between the two yoke-shaped projections.

[0013] In another example, an exemplary rotor assembly according to the present disclosure may include: a rotor mast connecting a motor to a rotor hub, the rotor mast rotatable about a first axis extending through the rotor mast; at least two blades connected to the rotor hub; a shaft connecting the at least two blades, the shaft rotatable about a second axis; a control rod; a swash plate connected to the shaft via the control rod; and a pitch lever connected to the shaft at a center of the shaft measured along the second axis, the pitch lever being configured to rotate the shaft about the second axis to simultaneously change the angle of attack of the at least two blades.

[0014] Various aspects of exemplary apparatus, systems, and methods relating to rotor assemblies according to the present disclosure may include one or more of the following features: the shaft is a single shaft that passes through the center of the rotor assembly measured along the second axis; the control rod is connected to the shaft via the pitch rod; the first end of the pitch rod is generally cylindrical and includes a hole configured to receive the shaft; the pitch rod extends toward the control rod in a direction perpendicular to the second axis; and the shaft is connected to the rotor hub via two yoke-shaped protrusions, the pitch rod being disposed between the two yoke-shaped protrusions.

[0015] In another example, an aircraft according to the present disclosure may include a first rotor assembly, the first rotor assembly comprising: a first group of at least two blades; a first shaft connected to the first group of at least two blades, the first shaft being rotatable about a first axis; and a first pitch control link connected to the first shaft at a center of the first shaft measured along the first axis and configured to rotate the first shaft along the first axis, thereby changing the angle of attack of the first group of at least two blades; and a second rotor assembly, the second rotor assembly comprising: a second group of at least two blades; a second shaft connected to the second group of at least two blades, the second shaft being rotatable about a second axis; and a second pitch control link connected to the second shaft at a center of the second shaft measured along the second axis and configured to rotate the second shaft along the second axis, thereby changing the angle of attack of the second group of at least two blades.

[0016] Various aspects of exemplary apparatuses, systems, and methods related to aircraft according to the present disclosure may include one or more of the following features: the first rotor assembly includes a first swashplate connected to the first shaft via a first control rod, and the second rotor assembly includes a second swashplate connected to the second shaft via a second control rod; the first control rod is connected to the first shaft via a first pitch change rod, and the second control rod is connected to the second shaft via a second pitch change rod; the first end of the first pitch change rod defines a cylindrical bore configured to receive the first shaft, and the first end of the second pitch change rod defines a cylindrical bore configured to receive the second shaft; the first group of at least two blades is configured to rotate per revolution via the connection with the first swashplate, and the second group of at least two blades is configured to rotate per revolution via the connection with the second swashplate; the first shaft is configured to simultaneously reduce a first angle of attack of a first blade of the first group of at least two blades and increase a second angle of attack of a second blade of the first group of at least two blades; and the second shaft is configured to simultaneously reduce a third angle of attack of a third blade of the second group of at least two blades and increase a fourth angle of attack of a fourth blade of the second group of at least two blades.

[0017] Additional objects and advantages of the disclosed embodiments will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the disclosed embodiments. The objects and advantages of the disclosed embodiments will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[0018] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosed embodiments, as claimed. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate various exemplary embodiments and, together with the description, serve to explain the principles of the disclosed embodiments.

[0020] Figure 1 An exemplary air traffic vehicle ("AMV") is depicted in accordance with one or more embodiments.

[0021] Figure 2 An exemplary rotor assembly is depicted according to one or more embodiments.

[0022] Figure 3A Depicted according to one or more embodiments Figure 2 An exemplary rotor assembly.

[0023] Figure 3B Depicted according to one or more embodiments Figure 3A Top view of the rotor assembly.

[0024] Figure 3C Describes the Figure 3B The plane corresponding to the line 3C-3C is intercepted Figure 3A A cross-sectional view of the rotor assembly.

[0025] Figure 3D Describes the Figure 3B The plane corresponding to the line 3C-3C is intercepted Figure 2 Cross-sectional view of the swash plate.

[0026] Figure 4 An exemplary rotor assembly is depicted according to one or more embodiments. DETAILED DESCRIPTION

[0027] The above summary and the following detailed description are merely exemplary and explanatory and do not limit the claimed features. As used herein, the terms "comprises," "comprising," "having," or other variations thereof are intended to encompass non-exclusive inclusions such that a process, method, article, or device comprising a series of elements includes not only those elements but may also include other elements not explicitly listed or inherent to such process, method, article, or device. In this disclosure, unless otherwise indicated, relative terms (such as, for example, "about," "substantially," and "approximately") are used to indicate a possible variation of ±10% on the stated value. In this disclosure, unless otherwise indicated, any numerical value may include a possible variation of ±10% on the stated value.

[0028] Even when used in conjunction with the detailed description of certain specific examples of the present disclosure, the terms used below should be interpreted in their broadest reasonable manner. In fact, certain terms may even be emphasized below; however, any term that is intended to be interpreted in any restrictive manner will be so openly and specifically defined in the detailed description section.

[0029] Various embodiments of the present disclosure generally relate to systems and methods for providing a rotor assembly for an AMV.

[0030] Some aircraft may include one or more blades that can be positioned in a substantially vertical orientation, allowing the aircraft to achieve vertical takeoff or maintain flight (e.g., to provide vertical lift). In such aircraft, loads generated by the rotation of the blades can be transferred to the fuselage via a hub assembly. Portions of the hub assembly may rotate with the blades, while portions of the hub assembly may remain stationary.

[0031] The swash plate can convert the pilot's flight control inputs into movement of the rotor blades so that, simultaneously: (1) the angle of attack of the advancing blades can be reduced, and (2) the angle of attack of the retreating blades can be increased to balance the lift generated by the advancing blades. The swash plate can convert control inputs from, for example, the pilot into rotational inputs that can be connected to the rotor blades or control surfaces. The swash plate can be controlled by one or more actuators that collectively and / or periodically change the pitch of the rotor blades. For example, the pilot and / or one or more electronic control systems of the aircraft (also referred to herein as "controllers") can use periodic control to adjust the roll or pitch of the AMV. For example, the periodic control can adjust the actuator that tilts the swash plate. The tilting of the swash plate can then cause the pitch rocker and control stick to rotate the angle of the blades and cause the aircraft to pitch or roll. The swash plate may require frequent inspection and maintenance to ensure the corresponding structural and operational integrity and generally increases the complexity of the rotor assembly. Some swash plates are complex in design and include many components that constitute a heavy assembly that is used in conjunction with the above-mentioned linkage mechanism, which can also be heavy.

[0032] As mentioned above, some rotor hubs may include a variable pitch rocker arm and control lever for each rotor blade. Equipping each rotor blade with a variable pitch rocker arm and control lever may increase the aircraft's suspended weight. This weight, suspended further from the rotor mast, may create stresses that require additional structural connections. Some hub assemblies may also struggle to accommodate the varying lift forces of different rotor blades, causing vibrations in the aircraft structure and potentially damaging the aircraft.

[0033] Exemplary disclosed embodiments include devices, systems, and methods for an aircraft rotor hub. In some embodiments, the aircraft may be an airplane capable of vertical takeoff and landing. In some embodiments, the aircraft may include a rotor having at least two blades. The blades may be configured to generate vertical lift. The blades may be attached to the aircraft via a shaft. The shaft may include one or more components that can rotate about an axis different from a "main" axis about which the blades rotate to generate propulsion. The shaft may be configured to rotate when a pitch lever is rotated. The shaft may: (1) rotate the blades about a shaft mast on a first axis different from the main axis, (2) change position relative to a second axis (e.g., the main axis) to adjust the angle of attack of the blades by a corresponding angle, and (3) rotate itself about the second axis (e.g., the main axis). The shaft may be connected to the aircraft via a single pitch lever and to a swash plate via a single control rod. The pitch lever may be configured to position the shaft about the second axis in response to tilting of the swash plate. As the shaft rotates about the first axis, the shaft itself may rotate along the second axis throughout a single rotation of the shaft about the first axis, based on the tilt of the swashplate. Throughout this rotation, the angle of attack of the blades may vary as the shaft rotates about the first axis. This adjustment in the angle of attack may be caused by the pitch control lever rotating the shaft through various angles throughout the rotation of the shaft about the first axis.

[0034] Consistent with the disclosed embodiments, the aircraft may include one or more rotors. The aircraft may be an airplane. Some non-limiting examples of aircraft may include a vertical take-off and landing aircraft, a helicopter, a quadcopter, an airship, an airplane, an unmanned aerial vehicle, or a drone. In some embodiments, the rotor assembly may be used without collective control. For example, in at least some embodiments, collective control may not be employed because the hub may be configured to change the pitch direction of the blades in equal and opposite directions. The total thrust may be adjusted by changing the speed (e.g., in rpm) of the motor driving the rotor.

[0035] Various embodiments of the present disclosure generally relate to systems and methods for providing a rotor assembly for an AMV (e.g., an eVTOL) that reduces hub weight and space requirements while also reducing drag. For aircraft using rotors or propellers, the exemplary rotors can further enable more efficient load transfer. For example, the hub design can reduce the aerodynamic torque generated by airflow passing through the rotor plane in a planar direction.

[0036] One or more embodiments may include a hub assembly that utilizes fewer components, which results in reduced weight (e.g., hanging weight) and space requirements, as well as drag. Fewer components can further reduce maintenance and costs. Reducing the weight of the hub assembly can further reduce vibration of the rotor mast. This can further reduce the number of components used to generate propulsion, for example, reducing maintenance and replacement costs.

[0037] One or more embodiments can efficiently adjust the angle of attack of a blade. For example, adjusting the angle of attack of two blades in a blade pair can provide more precise cyclic control. The system can be capable of adjusting the angle of attack of a blade using a single pitch lever and control rod. Thus, a separate pitch lever may not be required for each blade, and rotation of a single shaft can simultaneously adjust the angle of attack of multiple blades.

[0038] Figure 1 An exemplary AMV 101 according to one or more embodiments is depicted. The AMV 101 can include exemplary rotor assemblies 100a, 100b. Rotor assemblies 100a, 100b can correspond to any of rotor assemblies 100, 200, or 300 described herein. In some examples, the AMV 101 can be a vertical take-off and landing (VTOL) aircraft, a helicopter, other aircraft, or any other type of aircraft that would benefit from using the rotor assemblies described herein. Rotor assembly 100a can be a propeller rotor that can be positioned from a generally vertical orientation for take-off and landing to a generally horizontal orientation (e.g., for cruising as shown). Rotor assembly 100b can assist the AMV 101 in taking off or landing, and can also assist in maintaining the AMV 101 at a desired altitude, rate of ascent, or controlled rate of descent during flight.

[0039] Rotor assemblies 100a, 100b may, for example, receive commands in response to periodic control within AMV 101. Periodic control may be generated by a user interacting with controls within the cockpit of AMV 101 and / or by a controller.

[0040] Example rotor assemblies according to the present disclosure, including rotor assemblies 100a, 100b, can utilize variable-speed rotors connected to electric motors to vary the thrust of the example hub assembly described herein to produce cyclic pitch variation, which can reduce vibration forces and moments, thereby reducing system weight and providing a smoother ride for passengers. Thus, cyclic control can be applied to the example rotor assemblies described herein. Cyclic control can provide a method for reducing the loads on each rotor assembly 100a, 100b and improve the overall performance of AMV 101.

[0041] In some embodiments, where the aircraft includes more than one rotor assembly 100a, 100b, the rotor hub assembly may be actuated by actuating the swashplates (e.g., Figure 3A The swash plate 220 can reduce the oscillatory stress on the aircraft caused by the lift differences of different forces on different rotor hub assemblies.

[0042] Rotor assemblies consistent with the disclosed embodiments (e.g., rotor assembly 100a and / or rotor assembly 100b) can be connected to fixed-speed or variable-speed motors. In some embodiments, thrust can be adjusted to steer the aircraft (e.g., different rotors / rotor assemblies of the aircraft change direction at different speeds). In some embodiments, electric motors can be used as variable-speed motors to power the rotor assemblies.

[0043] For example, as will be discussed in greater detail below, a shaft within a rotor assembly (e.g., rotor assembly 100a and / or rotor assembly 100b) can be configured to rotate a first blade in a blade pair and increase the angle of attack of the first blade in the blade pair by a specific angle, while decreasing the angle of attack of a second blade in the blade pair by the same angle. Additionally, an alternative rotor assembly of an aircraft (e.g., rotor assembly 100a and / or rotor assembly 100b) can adjust its corresponding pitch at an angle independent of other rotor assemblies on the aircraft, thereby allowing independent control of the angle of attack of two or more rotor assemblies. For example, when the shaft (e.g., angle of attack) of a first rotor assembly is adjusted, this may create a lift difference between the first rotor assembly and any additional rotor assemblies.

[0044] Figure 2 An exemplary rotor assembly 100 is depicted according to one or more embodiments. Figure 2 As shown, rotor assembly 100 may include blade pairs 102, hub assembly 104, rotor mast 110, and one or more actuators (e.g., Figure 4 1 and 2. The first and second actuators 308 and 309 are shown in FIG. Portions of rotor assembly 100 may rotate (e.g., blade pairs 102, rotor mast 110, and portions of hub assembly 104) to generate thrust. In some examples, one or more actuators may include hydraulic actuators or electric motors. In still other examples, the actuators may include pneumatic actuators.

[0045] Blade pair 102 may include a first rotor blade 102a and a second rotor blade 102b. Rotor assembly 100 may include a first coupling 105a configured to operatively couple first rotor blade 102a to hub assembly 104. Rotor assembly 100 may include a second coupling 105b configured to operatively couple second rotor blade 102b to hub assembly 104. First coupling 105a and second coupling 105b may connect respective rotor blades to a shaft (e.g., Figure 3CThe first coupling member 105a and the second coupling member 105b are as shown in FIG. Figure 3C shown and will be described in more detail below.

[0046] First rotor blade 102a and second rotor blade 102b may have an airfoil shape. As first rotor blade 102a and second rotor blade 102b extend away from hub assembly 104, the shape of the blades may twist along first axis 150. First axis 150 may be formed by a shaft (e.g., Figure 3C Furthermore, as the blades extend further from hub assembly 104, the surface area of ​​blade pair 102 may decrease. Furthermore, as the blades extend further from hub assembly 104, the thickness of blade pair 102 may decrease.

[0047] although Figure 2 1, but some embodiments may include four blades. For example, hub assembly 104 may include two blade pairs 102, wherein each blade pair 102 includes two blades, and the blade pairs are spaced ninety degrees apart from first axis 150 and perpendicular to second axis 151. Furthermore, in this example, each blade pair 102 may include a plurality of blades. Figure 2 In other examples, the blade pair 102 may be an integral blade pair, thereby forming a one-piece structure comprising two blades integrally connected by a common shaft. Figure 2 The blades of blade pair 102 are shown in FIG. 1 as having a particular shape, but one of ordinary skill in the art will appreciate that other blade shapes are contemplated.

[0048] Hub assembly 104 may include a third coupling 103 that operatively couples a portion of hub assembly 104 to rotor mast 110. This third coupling 103 may be, for example, Figure 3A Inner ring 230 is shown. Third coupling 103 may secure a portion of hub assembly to rotor mast 110. As rotor mast 110 rotates along second axis 151, third coupling 103 may cause hub assembly 104 to rotate along second axis 151. When hub assembly 104 rotates along second axis 151, the hub assembly may cause blade pair 102 to rotate about second axis 151 via first coupling 105a and second coupling 105b. Second axis 151 may be an axis extending through blade pair 102 from the center of first rotor blade 102a to the center of second rotor blade 102b.

[0049] The hub assembly 104 may include a shaft (e.g., Figure 3C2. The shaft may extend from first rotor blade 102a to second rotor blade 102b and connect to blade pair 102 at first coupling 105a and second coupling 105b, respectively. As will be described in more detail below, the shaft of hub assembly 104 may be connected to the hub assembly 104 via other components in hub assembly 104 (e.g., via Figure 3A 150. The shaft may be rotated about first axis 150 to rotate pitch pull rod 216 and control rod 218 (shown in FIG. 150). This rotation of the shaft along first axis 150 may cause blade pair 102 to rotate to decrease or increase the angle of attack of blade pair 102 relative to first axis 150. Because first rotor blade 102a and second rotor blade 102b are coupled via the shaft, rotation of the shaft may cause the angle of attack between the two blades to adjust accordingly. For example, if the shaft is rotated fifteen degrees via hub assembly 104, both first rotor blade 102a and second rotor blade 102b may rotate fifteen degrees relative to first axis 150. Thus, the angle of attack (e.g., the angle relative to first axis 150) may be positive for first rotor blade 102a and negative for second rotor blade 102b, but at the same angle.

[0050] Hub assembly 104 may connect blade pairs 102 to each other and to an aircraft (e.g., Figure 2 101). Hub assembly 104 may further rotate along second axis 151 and transfer the rotational movement of rotor mast 110 to blade pair 102. This may generate thrust for rotor assembly 100. Hub assembly 104 may be connected to rotor mast 110 via third coupling 103. Third coupling 103 may allow portions of hub assembly 104 to rotate along second axis 151 with rotor mast 110. In some examples, third coupling 103 may be comprised of, for example, an inner ring (e.g., Figure 3C The rotor mast 110 may extend and be connected to a gearbox (not shown), for example via a drive shaft. The gearbox may be connected to a motor 160. The motor may be an electric motor.

[0051] Rotor mast 110 may be configured to rotate in response to commands from a user and / or a controller within AMV 101 that control motor 160 and / or an associated gearbox. Rotor mast 110 may be configured to further rotate the swash plate (e.g., Figure 3A Portions of the swash plate 220 and the blade pair 102 are shown.

[0052] Figure 3A A rotor assembly 200 is depicted according to one or more embodiments. Certain features of the rotor assembly 200 may be similar to those described above with reference to FIG. Figure 2 Certain features of the discussed rotor assembly 100 are similar.

[0053] Rotor assembly 200 may include first blade 202a and second blade 202b coupled to rotor hub 204 (e.g., rotor hub assembly) at first coupling 205a and second coupling 205b, respectively. In one example, first blade 202a and second blade 202b may be positioned along the same axis of rotation (e.g., first axis 150). First blade 202a may be 180 degrees from second blade 202b relative to second axis 151. First blade 202a may include an airfoil portion 209a and a connecting portion 207a. Airfoil portion 209a may be in the shape of an airfoil and may help generate lift when in contact with air. Connecting portion 207a may extend from airfoil portion 209a and be located closest to rotor hub 204. The connecting portion 207a may have a hollow interior that is capable of receiving shaft 206 (also in the shaft) from rotor hub 204. Figure 3C ). The connection portion 207a of the first blade 202a is combined with the shaft 206 of the rotor hub 204 to form a first coupling member 205a.

[0054] Similar to first blade 202a, second blade 202b may include an airfoil portion 209b and a connecting portion 207b. Airfoil portion 209b may be in an airfoil shape and may help generate lift when in contact with air. Connecting portion 207b may extend from airfoil portion 209b and be located closest to rotor hub 204. Connecting portion 207b may have a hollow interior shape (e.g., a portion located at the bottom of the rotor hub) that can receive a shaft from rotor hub 204. Figure 3C The connection portion 207b of the second blade 202b is combined with the shaft of the rotor hub 204 to form a second coupling member 205b.

[0055] Connecting portions 207a, 207b may also receive shaft 206. Rotor assembly 200 may, for example, be a rigid rotor assembly. Shaft 206 may be received along first axis 150. Furthermore, each connecting portion 207a, 207b may include a plurality of through-holes 211a, 211b extending through connecting portion 207a, 207b. In one example, connecting portions 207a, 207b may each have two through-holes 211a, 211b. In another example, connecting portions 207a, 207b may each have a single through-hole 211a, 211b. In yet another example, connecting portions 207a, 207b may have three or more through-holes 211a, 211b.

[0056] Through-holes 211a, 211b may be configured to receive fasteners 213a, 213b and secure first blade 202a and second blade 202b to shaft 206 of rotor hub 204. In some examples, through-holes 211a, 211b may be threaded. In other examples, instead of or in addition to threaded versions of through-holes 211a, 211b, first coupling 105a and second coupling 105b may include a plurality of nuts that screw into threaded portions of bolts provided as fasteners. In another example, first blade 202a and second blade 202b may be connected to rotor hub 204 using a clamp, adhesive, press fit, or other attachment techniques known to those skilled in the art. In examples where blades 202a and 202b are integrally formed with each other and with shaft 206, through-holes 211a, 211b may be omitted.

[0057] Rotor assembly 200 may also include a first yoke 212a and a second yoke 212b. First yoke 212a and second yoke 212b may each be a portion of rotor mast 210 or a portion of hub assembly 104 ( Figure 2 In one example, yokes 212a, 212b may be configured to extend parallel to rotor mast 210 in a first portion and then extend laterally outwardly at an angle relative to second axis 151 toward respective first blade 202a, second blade 202b in a second portion (e.g., Figure 3C ). Yoke 212a may extend outward in a direction toward first blade 202a. Yoke 212b may extend outward in a direction toward second blade 202b. The cross-sectional shape of the second portion of yokes 212a, 212b may be circular. The ends of yokes 212a, 212b may extend beyond rotor mast 210 relative to second axis 151. Yokes 212a, 212b may each include a respective head located at an end farthest from where yokes 212a, 212b are connected to rotor mast 210. The heads of yokes 212a, 212b may include holes 215a, 215b capable of receiving shaft 206. Holes 215a, 215b may be aligned with first axis 150.

[0058] Yokes 212a, 212b may include one or more bearings 262. One or more bearings may be elastomeric bearings or ball bearings. The elastomeric bearings may be conical or tapered elastomeric bearings. In some embodiments, the elastomeric bearings may be spherical, cylindrical, or any other shape or configuration known to those skilled in the art.

[0059] although Figure 3AA set of two yokes 212a, 212b is shown in FIG, but those skilled in the art will appreciate that other numbers of yokes may be envisioned. For example, if the hub assembly includes a third or fourth blade, each additional blade may include an additional yoke.

[0060] The rotor assembly may further include a linkage 250 extending from a first end (e.g., pitch rod 216) to a second end (e.g., control rod 218). The first end of linkage 250 may be formed on pitch rod 216. The second end of linkage 250 may be formed on control rod 218. Linkage 250 may be configured to rotate shaft 206 about first axis 150. For example, vertical movement of control rod 218 may move pitch rod 216, which may cause shaft 206 to rotate along first axis 150. As described above, rotation of the shaft may increase and / or decrease the angle of attack of first blade 202a and second blade 202b, respectively, via first coupling 205a and second coupling 205b.

[0061] The pitch control rod 216 can include a first end 217 including a bore capable of receiving the shaft 206. The first end 217 can be generally cylindrical and include a bore having a circular cross-section when viewed along the first axis 150. The bore of the first end 217 can include a lock washer configured to provide a locking mechanism for a nut that holds the shaft 206 to the first end 217. In another example, the bore of the first end 217 can be shaped to receive the shaft 206. In another example, the cross-section of the bore of the first end 217 can be oval, rectangular, or other geometric or non-geometric shapes. The first end 217 can be disposed between the two yokes 212a, 212b.

[0062] The first end 217 of the pitch control rod 216 can be coupled to the shaft 206. The first end 217 can include a gear positioned between the couplings and received by gear teeth (not shown) in the shaft 206. This coupling can facilitate rotation of the shaft 206. This coupling can occur at a substantially central point along the length of the shaft 206. This can be the most central point of the shaft 206. The center can be measured relative to and along the first axis 150. For example, the center of the shaft can be a point and / or area of ​​the shaft that is equidistant from the first blade 202a and the second blade 202b. In some embodiments, this coupling can be performed by fasteners such as bolts or clamps.

[0063] The variable pitch rod 216 can extend from a first end 217 in a direction perpendicular to the first axis 150. The extension of the variable pitch rod 216 from the first end 217 to the second end 219 can include a single arm 221. The single arm 221 can be connected to the first end 217 at an axial center point of the shaft 206. The contact point between the single arm 221 and the first end 217 can be generally radial or curved to match the shape of the shaft 206 and avoid stress accumulation at the junction of the first end 217 and the first arm 221.

[0064] Furthermore, in one example, the single arm 221 may include a second arm 221a and a third arm (not shown) extending from a midpoint of the single arm 221 and coupled to opposite axial sides of the first end 217. In other examples, multiple arms may be coupled from the first end 217 to the second end 219 of the variable pitch rod 216. In another example, only a single arm 221 may be included within the variable pitch rod 216.

[0065] The second end 219 of the pitch change rod 216 can be coupled to a control rod 218. Movement of the control rod 218 (e.g., as the control rod 218 is raised or lowered by the swashplate 220) can cause the second end 219 of the pitch change rod 216 to pivot relative to the first axis 150. The radial movement of the second end 219 can cause the first end 217 of the pitch change rod to rotate about the first axis 150.

[0066] The control rod 218 may have a first end 223 and a second end 225. The first end 223 of the control rod 218 may be coupled to the second end 219 of the pitch rod 216. The first end 223 of the control rod 218 may be shaped as a fork. Each tip of the fork may have a hole. A rod may extend through each tip of the fork and through the hole of the second end 219 of the pitch rod 216. This may form a semi-rigid connection between the pitch rod 216 and the control rod 218. The first end 223 of the control rod 218 may be connected to the second end 225 via one or more rods (e.g., a first rod 224a and a second rod 224b). The first rod 224a and the second rod 224b may be separated by an opening 226. The length of the opening between the first rod 224a and the second rod 224b may decrease between the first end 223 and the second end 225. The shape of the control rod 218 may be configured to allow the control rod 218 to perform both pitch change and drive link functions.

[0067] The second end 225 of the control rod 218 may be coupled to the swash plate 220. Such coupling may be performed by welding, bolts, clamps, press fits, or any other attachment method known to those of ordinary skill in the art.

[0068] The swash plate 220 may include an inner ring 230, a fixed ring 234, an outer ring 232 (e.g., a rotating ring), and an inclined ball joint connection 236 configured to couple the fixed ring 234 and the outer ring 232. The swash plate 220 may include one or more couplings capable of coupling the swash plate 220 to an actuator. For example, the swash plate 220 may have an actuator fork 238 (e.g., a connecting rod) capable of coupling to the actuator. In another example, the swash plate 220 may have two actuator couplings (e.g., a connecting rod). Figure 4 2 and 3. Actuator fork 238 may be fork-shaped and have two separate flanges extending from swashplate 220 in a direction opposite to rotor hub 204. In one example, the two separate flanges may extend away from swashplate 220 at an angle of approximately 45 degrees relative to the surface of swashplate 220. The two separate flanges of actuator fork 238 may each include a hole at one end opposite the connection to swashplate 220. The holes may be configured to receive bolts or connecting elements that can couple actuator fork 238 to an actuator. In another example, the shape of actuator fork 238 may have a single flange or be configured to receive various other shapes of an actuator. Actuator fork 238 may be connected to swashplate 220 at retaining ring 234.

[0069] The swash plate 220 may be located below the control rod 218. The inner ring 230 of the swash plate may be annular. The inner ring 230 may be aligned so that the opening in the cylinder is aligned with the second axis 151. The inner ring 230 may be non-rotating. The inner ring 230 may also be coupled to and circumferentially surround a portion of the rotor mast 210 (e.g., Figure 3D In another example, inner ring 230 may surround rotor mast 210 and tilt ball (e.g., as shown in FIG. Figure 4 346 is shown). Inner ring 230 may be configured to rotate with rotor mast 210. Inner ring 230 may also include a lip extending radially from inner ring 230. The lip may be located at the end farthest from rotor hub 204. The lip may include holes spaced along the lip. Inner ring 230 may also include portions that connect inner ring 230 to retaining ring 234 and / or outer ring 232 (e.g., as shown). Figure 3D Connecting element 237 shown).

[0070] A retaining ring 234 of swashplate 220 may be located radially outward of inner ring 230. Retaining ring 234 of swashplate 220 may be configured to remain stationary in the rotational direction as rotor mast 210 rotates. Retaining ring 234 may, for example, include an anti-rotation link to prevent rotation of retaining ring 234. Retaining ring 234 may be configured to tilt relative to second axis 151. Furthermore, retaining ring 234 may be configured to move upward and downward (e.g., translate). Retaining ring 234 may be connected to one or more actuator forks (e.g., actuator forks 238). In another example, retaining ring 234 may include two actuator forks positioned circumferentially at 90 degrees relative to second axis 151. Retaining ring 234 may be configured to tilt swashplate 220 in response to coupling with an actuator. Retaining ring 234 may be coupled to outer ring 232 (e.g., the swashplate) via a tilting ball joint connection 236.

[0071] The outer ring 232 can be generally annular with its opening aligned with the second axis 151. A portion of the outer ring 232 can extend as a semicircle outside the conventional annular shape. The outer semicircle can include a coupling for connecting the outer ring 232 to the second end 225 of the control rod 218. The coupling can include a hole or groove configured to receive a fastener that secures the corresponding end of the control rod 218 (e.g., the second end 225 of the control rod 218).

[0072] Tilt ball joint connection 236 may include a bearing. The bearing may be a ball bearing, a spherical bearing, or any other bearing known to those skilled in the art to allow relative movement of the swash plate relative to the rotor mast. Tilt ball joint connection 236 may be located between outer ring 232 and stationary ring 234. Tilt ball joint connection 236 may allow outer ring 232 and stationary ring 234 to tilt synchronously while outer ring 232 rotates and stationary ring 234 does not rotate.

[0073] The swash plate 220 can be configured to tilt as a unit relative to the second axis 151. For example, movement of the fixed ring 234 can move the entire swash plate 220 through its connection with the outer ring 232. This tilting can then cause movement of the variable pitch rod 216 and the control rod 218.

[0074] The swashplate 220 may be configured to cause movement of the pitch control rod 216 and the control rod 218, thereby rotating the shaft 206 along the first axis 150. The swashplate 220 may be configured to move due to a linear or rotary actuator, as will be described in greater detail below. The swashplate 220 may be located below the control rod 218 and configured to provide cyclic pitch control for both the first blade 202a and the second blade 202b.

[0075] Figure 3B Depicted according to one or more embodiments Figure 2 Top view of the rotor assembly.

[0076] In one example, the variable pitch link 216 can extend from the control rod 218 along a single arm 221. The width of the arm 221 can increase in a direction toward the first end 217.

[0077] Figure 3C Describes the Figure 3B The plane corresponding to the line 3C-3C is intercepted Figure 2 A cross-sectional view of the rotor assembly. Figure 3C As shown, shaft 206 can extend from first blade 202a to second blade 202b. Shaft 206 can be a solid shaft or a hollow shaft. The shaft can include, but is not limited to, the following materials: aluminum, titanium, steel, or a composite of these materials. The cross-section of shaft 206 can be, for example, circular, oval, or rectangular. Shaft 206 can pass through one or more yoke-shaped protrusions (e.g., yoke 212a and yoke 212b).

[0078] When the shaft is not rotating, first blade 202a and second blade 202b can be coupled to shaft 206 in an inclined configuration. If first blade 202a can be set to a specific position, such as rotated "X" degrees clockwise relative to shaft 206, second blade 202b can also be set to that position (or "X" degrees), but rotated counterclockwise relative to the shaft. In one example, if first blade 202a is set to rotate 5 degrees clockwise relative to shaft 206, second blade 202b can also be set to rotate 5 degrees counterclockwise relative to shaft 206. As discussed in more detail below, first blade 202a and second blade 202b can rotate simultaneously based on the rotation of shaft 206.

[0079] Rotor mast 210 may further include a hollow chamber 228 extending along second axis 151. A gap 246 may exist between the end of rotor mast 210 furthest from AMV 101 and shaft 206.

[0080] Figure 3D Describes the Figure 3B The plane corresponding to the line 2A-2A is intercepted Figure 2 FIG2 is a cross-sectional view of a swash plate assembly. Inner ring 230 may include portions extending perpendicular to inner ring 230 as two flanges to receive other components of swash plate 220 (e.g., retaining ring 234). The connection between inner ring 230 and retaining ring 234 may include a bearing or tilting ball joint connection 241 and a connecting element 237. The bearing may be a ball bearing, a spherical bearing, or any other bearing known to those skilled in the art to allow relative movement of the swash plate relative to the rotor mast.

[0081] Additionally, retaining ring 234 and outer ring 232 (not shown) may be coupled via bearings (not shown). Retaining ring 234 may be configured to receive connections to one or more actuators. Outer ring 232 (not shown) may include connections to control rods and pitch rods (e.g., control rod 218 and pitch rod 216).

[0082] Figure 4 An exemplary rotor assembly according to one or more embodiments is depicted. Certain features of rotor assembly 300 may be similar to those described above with reference to Figures 3A to 3C Features of the exemplary hub assembly discussed above. Discussion of similar features will be omitted.

[0083] Rotor assembly 300 may include a swash plate 320. Swash plate 320 may include one or more extensions to couple the actuator to swash plate 320. For example, swash plate 320 may include a first coupling 338 and a second coupling 340. First coupling 338 may include a fork extending from swash plate 320. The fork may extend from a fixed ring (e.g., Figures 3A to 3C The fork may have two separate flanges extending from the swash plate 320 along the axis of the rotor hub 204 (e.g., Figure 3A 320 ). In one example, the two separate flanges may extend in opposite directions from the swash plate 320 at an angle of approximately 45 degrees relative to the surface of the swash plate 320. The two separate flanges of the fork may each include a hole at one end opposite the connection portion of the swash plate 320. The holes may be configured to receive bolts or connecting elements that can connect the flanges to the actuator and thus implement the first coupling 338. In another example, the shape of the actuator fork may have a single flange or various other shapes configured to receive an actuator. The second coupling 340 may have the same or similar components as the first coupling 338, but may be used to connect a second actuator (e.g., the second actuator 309) to the swash plate 320.

[0084] The swash plate 320 may be configured to rotate about the tilting ball 346. The first coupling 338 and the second coupling 340 may be positioned 90 degrees apart from each other circumferentially relative to the second axis 151.

[0085] First coupling 338 and second coupling 340 may be configured to transmit movement of actuators (e.g., first actuator 308 and second actuator 309) to the hub to facilitate cyclic pitch control of rotor blades (e.g., first rotor blade 302a and second rotor blade 302b).

[0086] The first actuator 308 can be connected to the first coupling 338. In one example, a rod can extend from the first actuator 308 toward the first coupling 338 and be connected using bolts or fasteners.

[0087] The second actuator 309 can be connected to the second coupling 340. In one example, a rod can extend from the second actuator 309 toward the second coupling 340 and be connected using bolts or fasteners.

[0088] In some examples, the first actuator 308 and the second actuator 309 may include hydraulic actuators. The first actuator 308 and the second actuator 309 may be capable of receiving a signal (e.g., from a manually operated periodic control and / or controller) and converting source energy into mechanical motion in response to the signal. For example, the motion may be linear and cause the corresponding coupling (e.g., the first coupling 338, e.g., the second coupling 340) to move in a linear motion. The linear motion may be toward and away from the swash plate 320. In other examples, the first actuator 308 and the second actuator 309 may include similar components and operate in a manner similar to a solenoid. In yet other examples, the actuators may include pneumatic actuators. The first actuator 308 and the second actuator 309 may be linear actuators or rotary actuators.

[0089] In another example, swashplate 320 may include additional couplings and actuators. For example, swashplate 320 may include only a single actuator coupling and actuator. In another example, swashplate 320 may include four actuator couplings and actuators. Rotor assembly 300 may include more than one actuator to achieve different orientations, as opposed to simply attaching a single actuator. For example, if only a single actuator were present, swashplate 320 could tilt along only a single axis. Two or more actuators may allow swashplate 320 to translate along a plane rather than a single axis.

[0090] The first and second actuators 308, 309 may have respective second ends 342, 344 opposite the ends of the couplings 338, 340. The second ends 342, 344 may extend from the body of the actuator away from the swashplate 320. The second ends 342, 344 may be connected to a cyclic control, such as the AMV 101.

[0091] operate:

[0092] Now refer to Figures 1 to 4 The operation of the hub assemblies (e.g., 100, 200, and 300) described in.

[0093] While flying within AMV 101 or during takeoff or landing, a user and / or controller (e.g., an autopilot or other flight control system) can adjust the cyclic control of AMV 101. In response to the cyclic control adjustments, actuators (e.g., first actuator 308 and second actuator 309) can tilt the stationary ring (e.g., stationary ring 234) of swashplate 320. Because the rotor assembly can include two actuators, swashplate 320 can tilt throughout its entire range of motion relative to an axis (e.g., second axis 151). As the stationary ring tilts, the bearing between the stationary ring and the rotating swashplate (e.g., outer ring 232) may also tilt at the same angle as the stationary ring. This tilting may first move control rod 318 and then move pitch control rod 316. Movement of pitch control rod 316 may cause a shaft (e.g., shaft 206) to rotate along an axis (e.g., first axis 150). Because the shaft is connected to the blades (e.g., first rotor blade 302a and second rotor blade 302b), the blades can rotate relative to the shaft. The two blades can rotate simultaneously and change the angle of attack. Pitch rod 316 can also be a driving force that causes the shaft and blades to rotate about second axis 151, thereby generating lift for the rotor assembly. As the shaft rotates about second axis 151, a control rod (e.g., control rod 318) can move up and down according to the inclination of the swash plate (e.g., swash plate 320) relative to second axis 151. This can cause the blades (e.g., first blade 302a and second blade 302b) to change angle throughout a single rotation of the blades about second axis 151. Since the two blades are connected by a single shaft 206, a change in the angle of one blade can correspond to a change in the angle of the other blade.

[0094] During AMV operation, the blades (e.g., first blade 202a and second blade 202b) can rotate about first axis 150 and second axis 151 to address and control changes in airspeed. When the airspeed against the AMV increases (e.g., as the wind speed increases or the aircraft moves, the airflow increases), the advancing blade (e.g., moving against the airflow) can reduce the angle of attack (e.g., the angle relative to first axis 150) to maintain a determined vertical thrust level. When the airspeed against the aircraft decreases, the advancing blade can increase the angle of attack. When the airspeed against the aircraft increases (e.g., as the wind speed increases or the aircraft moves, the airflow increases), the retreating blade (e.g., moving with the airflow) can reduce the angle of attack to maintain a determined vertical thrust level. Alternatively, when the airspeed against the aircraft decreases, the retreating blade can reduce the angle of attack. The determined thrust level may be based on a selected thrust, where the selected thrust may be higher to generate lift (e.g., increase altitude), lower to reduce lift (e.g., decrease altitude), or at a level to maintain lift (e.g., maintain altitude).

[0095] During AMV operation, the first rotor assembly and the second rotor assembly can operate independently or in unison and respond to periodic control. Both the first rotor and the second rotor can correspond to any of the rotor assemblies 100, 200 or 300 described herein. The first rotor assembly may include: a first group of at least two blades; a first shaft connecting the first group of at least two blades; a first pitch lever, the first pitch lever connected to the first shaft and configured to change the angle of attack of the first group of at least two blades. The second rotor assembly may include: a second group of at least two blades; a second shaft connecting the second group of at least two blades; and a second pitch lever, the second pitch lever connected to the second shaft and configured to change the angle of attack of the second group of at least two blades. Both the first rotor and the second rotor assembly can operate independently as described above.

[0096] In some embodiments, the blades (e.g., first blade 202a and second blade 202b) may rotate per revolution about second axis 151. In some embodiments, an actuator configured to act on pitch lever 216 and / or control rod 218 may affect the oscillation setting of the blades.

[0097] In some embodiments, where an aircraft includes more than one rotor hub assembly, oscillatory stresses on the aircraft caused by lift differences due to different forces on different rotor hub assemblies may be reduced by actuating the swashplates of one or more rotor hub assemblies.

[0098] Rotor assemblies consistent with the disclosed embodiments can be connected to fixed-speed or variable-speed motors. In some embodiments, where the rotor assembly is connected to a variable-speed motor, thrust can be adjusted to steer the aircraft (e.g., different rotors / rotor assemblies of the aircraft have different speeds to change direction of travel). In some embodiments, an electric motor can be used as a variable-speed motor to drive or move the disclosed rotor assembly.

[0099] One or more embodiments may include a hub assembly that utilizes fewer components, which results in reduced weight and space requirements, as well as drag. Reducing the weight of the hub assembly may further reduce vibration of the motor mast.

[0100] One or more embodiments can effectively adjust the angle of attack of a blade. For example, corresponding changes in the blade angle of attack can achieve more precise cyclic control. The system can be capable of using a single pitch rod and control rod to adjust the corresponding angle of attack of the blade. A separate pitch rod may not be required for each blade.

[0101] Throughout this disclosure, references to components or modules generally refer to items that can be logically grouped together to perform a function or a group of related functions. Identical reference numerals generally refer to identical or similar components. Components and modules can be implemented using software, hardware, or a combination of software and hardware.

[0102] The above-described tools, modules, and functions (including controllers) may be executed by one or more processors.

[0103] It will be apparent to those skilled in the art that various modifications and variations may be made to the disclosed structures. Although exemplary embodiments have been described herein, the scope of the present disclosure includes any and all embodiments with equivalent elements, modifications, omissions, combinations (e.g., aspects of the various embodiments), adaptations, and / or changes that would be understood by those skilled in the art based on the present invention. The limitations in the claims should be interpreted broadly based on the language used in the claims and are not limited to the examples described in this specification or during the examination of the application, which examples should be interpreted as non-exclusive. In addition, the steps of the disclosed method may be modified in any way, including reordering steps and / or inserting or deleting steps, without departing from the principles of the present disclosure. Therefore, it is intended that this specification and embodiments be understood as exemplary only, with the true scope and spirit of the present disclosure being indicated by the full scope of the appended claims and their equivalents.

Claims

1. A rotor assembly comprising: a rotor mast connected to the motor and the rotor hub, the rotor mast being rotatable about a first axis; a plurality of blades connected to the rotor hub; The rotor hub includes a shaft connected to the blades, and the shaft is rotatable about a second axis; a swash plate connected to the rotor mast and the shaft; and a single linkage extending from a first end coupled to the shaft to a second end coupled to the swash plate, the single linkage configured to convert motion of the swash plate into rotation of the shaft about the second axis, thereby simultaneously rotating the blade about the second axis. 2 . The rotor assembly of claim 1 , wherein the first end of the single linkage is formed on a pitch rod, and the second end of the single linkage is formed on a control rod. 3 . The rotor assembly of claim 2 , wherein the pitch lever is coupled to the shaft at a center-most point of the shaft.

4. The rotor assembly of claim 2, wherein the first end of the pitch change rod is generally cylindrical and includes a bore configured to receive the shaft, wherein the first end of the pitch change rod forms the first end of the single linkage.

5. The rotor assembly of claim 4, wherein a second end of the pitch change rod opposite the first end of the pitch change rod is coupled to the control stick, wherein the second end of the pitch change rod is configured to pivot when raised or lowered by the control stick. 6 . The rotor assembly of claim 1 , wherein the shaft is configured to simultaneously decrease a first angle of attack of a first blade and increase a second angle of attack of a second blade.

7. The rotor assembly of claim 1, wherein the shaft is connected to the rotor mast via two yoke-like projections, the first end of the single linkage being disposed between the two yoke-like projections.

8. A rotor assembly comprising: a rotor mast connecting the motor to the rotor hub, the rotor mast being rotatable about a first axis extending through the rotor mast; at least two blades connected to the rotor hub; a shaft connecting the at least two blades, the shaft being rotatable about a second axis; control lever; a swash plate connected to the shaft via the control rod; and A pitch rod is connected to the shaft at a center of the shaft measured along the second axis, the pitch rod being configured to rotate the shaft about the second axis to simultaneously change the angle of attack of the at least two blades.

9. The rotor assembly of claim 8, wherein the shaft is a single shaft passing through a center of the rotor assembly measured along the second axis.

10. The rotor assembly of claim 9, wherein the control rod is connected to the shaft via the pitch rod.

11. The rotor assembly of claim 9, wherein the first end of the pitch control rod is generally cylindrical and includes a bore configured to receive the shaft.

12. The rotor assembly of claim 11, wherein the pitch lever extends toward the control rod in a direction perpendicular to the second axis.

13. The rotor assembly of claim 8, wherein the shaft is connected to the rotor hub by two yoke-like protrusions. 14 . The rotor assembly according to claim 13 , wherein the pitch change rod is disposed between the two yoke-shaped protrusions.

15. An aircraft comprising: A first rotor assembly, the first rotor assembly comprising: The first set has at least two paddles; a first shaft connected to the first set of at least two blades, the first shaft being rotatable about a first axis; and a first pitch control link connected to the first shaft at a center of the first shaft measured along the first axis and configured to rotate the first shaft along the first axis to change the angle of attack of the first set of at least two blades; and A second rotor assembly, the second rotor assembly comprising: the second set of at least two paddles; a second shaft connected to the second set of at least two blades, the second shaft being rotatable about a second axis; and A second pitch rod is connected to the second shaft at a center of the second shaft measured along the second axis and is configured to rotate the second shaft along the second axis to change the angle of attack of the second group of at least two blades.

16. The aircraft of claim 15, wherein the first rotor assembly includes a first swash plate connected to the first shaft via a first control rod, and the second rotor assembly includes a second swash plate connected to the second shaft via a second control rod. 17 . The aircraft of claim 16 , wherein the first control stick is connected to the first shaft via the first pitch change rod, and the second control stick is connected to the second shaft via the second pitch change rod.

18. The aircraft of claim 16, wherein the first end of the first pitch change rod defines a cylindrical bore configured to receive the first shaft, wherein the first end of the second pitch change rod defines a cylindrical bore configured to receive the second shaft.

19. The aircraft of claim 16, wherein the first set of at least two blades are configured to rotate per revolution via connection to the first swash plate, and the second set of at least two blades are configured to rotate per revolution via connection to the second swash plate.

20. The aircraft of claim 15, wherein the first shaft is configured to simultaneously reduce a first angle of attack of a first blade in the first group of at least two blades and increase a second angle of attack of a second blade in the first group of at least two blades; and the second shaft is configured to simultaneously reduce a third angle of attack of a third blade in the second group of at least two blades and increase a fourth angle of attack of a fourth blade in the second group of at least two blades.

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