Flying car rotor device

Abstract

A flying car is disclosed that includes a first rotor assembly, a second rotor assembly, and a pylon for the second rotor assembly configured to attach the second rotor assembly to the rest of the flying car. The first rotor assembly and the second rotor assembly are spaced apart in the longitudinal direction of the flying car and positioned substantially on a vertical plane parallel to a vertical plane aligned with the longitudinal axis of the flying car. The first rotor assembly includes a tilt rotor configured to tilt between substantially vertical flight thrust and substantially steady flight thrust. The second rotor assembly includes multiple stacked rotors that provide substantially vertical thrust and are attached to the pylon so as to be on substantially the same side of the pylon.

Description

[Technical Field]

[0001] The present disclosure relates to a rotor device for a flying car. One aspect relates to a flying car. Embodiments may have particular application to, but are not limited to, aircraft with distributed propulsion systems, such as vertical take-off and landing (VTOL) capable air taxis. [Background technology]

[0002] For purposes of illustration, but not limitation, the background art will now be described in the context of VTOL air taxis.

[0003] Recent technological developments have enabled the development of a new class of aircraft, capable of high cruise speeds and VTOL capability through the use of distributed electric propulsion systems, which may enable a high level of safety due to redundancy, low operating costs, and a low noise signature.

[0004] However, challenges remain regarding the choice of airframe and propulsion system architecture, with the main challenge being to configure the aircraft to enable efficient VTOL flight and efficient cruise at high speeds while maintaining sufficient redundancy in all systems. Summary of the Invention

[0005] The flying car provided according to a first aspect optionally comprises a first rotor assembly, a second rotor assembly, and a pylon for the second rotor assembly configured to attach the second rotor assembly to the rest of the flying car. In the first aspect, the first rotor assembly and the second rotor assembly are arranged to be spaced apart in the longitudinal direction of the flying car and to be positioned substantially on a vertical plane parallel to a vertical plane aligned with the longitudinal axis of the flying car. In the first aspect, the first rotor assembly may comprise a tilt rotor configured to tilt between a substantially vertical flight thrust supply attitude and a substantially steady flight thrust supply attitude. In the first aspect, the second rotor assembly may comprise multiple stack rotors (vertical thrust rotors) attached to substantially the same side of the pylon and stacked on each other to supply substantially vertical thrust.

[0006] The first rotor assembly and the second rotor assembly are arranged side by side so as to be spaced apart in the longitudinal direction of the flying car and to be located substantially on a vertical plane parallel to a vertical plane aligned with the longitudinal axis of the flying car. In this arrangement, there may be an axis parallel to the longitudinal axis of the flying car, along which a projection of one of the first rotor assembly and the second rotor assembly toward the other may at least partially overlap the other. The degree of such arrangement may be sufficient so that potentially significant turbulence generated by the upstream assembly of the first rotor assembly and the second rotor assembly is blocked by the downstream assembly.

[0007] The use of tilt rotors can facilitate improved cruise flight efficiency, and tilt rotors can contribute vertical thrust during vertical and transition flight configurations. The use of multiple stacked rotors, stacked together to provide substantial vertical thrust, can provide additional vertical thrust without the need for a heavier tilt rotor. Thus, the combination of tilt rotors and stack rotors can provide improved performance and / or additional flight configuration options. Having the first and second rotor assemblies spaced apart longitudinally (and optionally vertically) and with a substantially common lateral axis displacement can be desirable or advantageous for various reasons (e.g., dynamic considerations, weight distribution, packaging, reduced complexity, component supply, system sharing, etc.). However, during at least some flight configurations, one of the first and second rotor assemblies is likely to be subject to turbulence from the other.

[0008] Providing the blades of the multiple stack rotors on one side of the pylon (e.g., without being separated by the pylon) may mean that the spacing between the multiple stack rotors can be reduced (to the point where they are not substantially spaced apart). This reduces the possibility of blade vortex interaction between the rotors, improving efficiency and noise performance. The closer proximity of the multiple stack rotors may also allow them to be adjustable between a stowed configuration (e.g., when not in use during steady flight) and a deployed configuration (when vertical thrust from the stack rotors is required). In the stowed configuration, the blades of each stack rotor may be aligned with the corresponding blades of the other stack rotors, and the multiple stack rotors are oriented in a direction of rotation that presents a substantially minimum total frontal cross section to reduce the drag they cause. This effect may be more significant (at least in some flight configurations) if a stack rotor impinges on or ingests at least a portion of the wake of another rotor (e.g., a tilt rotor). However, the closer proximity between the multiple stack rotors may instead allow for a smaller overall package (unit) of multiple stack rotors. This may facilitate positioning to largely or completely avoid the tilt rotor's wake, despite the continued presence of the tilt rotor, which may provide potential benefits. Closer proximity between multiple stack rotors may also allow spacing such that the stack rotor acts as a single multi-element lifting airfoil, with potential efficiency, dynamic, and noise benefits. Closer proximity between multiple stack rotors may also allow for the sharing of parts to support and enable the stack rotors (for example), thereby reducing complexity and / or weight.

[0009] In some embodiments, the first rotor assembly and the second rotor assembly are arranged so that both are substantially coaxially parallel to the longitudinal axis of the flying car. Thus, for example, the centerlines and / or rotation axes of the first rotor assembly and the second rotor assembly may be coaxially parallel to the centerline axis of the flying car. Having one of the first and second rotor assemblies located substantially immediately downstream of the other (in steady-state flight) may be desirable for various reasons (e.g., dynamic considerations, weight distribution, packaging, reduced complexity, component sharing, system sharing, etc.). Furthermore, by arranging multiple stacked rotors on one side of the supporting pylon, potential drawbacks associated with this arrangement (e.g., the effects of turbulence) may be at least partially mitigated (as discussed above).

[0010] In some embodiments, the spacing between the stack rotors of the second rotor assembly is substantially less than 100% of the mean aerodynamic chord length of the blades of the stack rotors. In other embodiments, the spacing between the stack rotors of the second rotor assembly is substantially less than 80%, 60%, 40%, 30%, or 20% of the mean aerodynamic chord length of the blades of the stack rotors. Such proximity may emphasize at least some of the potential advantages of the present invention described above, which are further enhanced as the spacing between the stack rotors is reduced. However, there may be some trade-off in that the design freedom of the blade hubs may be limited as the spacing between the stack rotors is reduced.

[0011] In some embodiments, no static structures are located within the annulus defined between the blade planes of at least one pair of stack rotors. By avoiding static structures (e.g., pylons or nacelles) between the rotating blades, multiple stack rotors can be placed closer together, avoiding airflow interference (and thus disrupting the cooperative aerodynamic effects between the stack rotors).

[0012] In some embodiments, the first rotor assembly is located further forward on the flying car body than the second rotor assembly. This configuration may be desirable for various reasons, such as when more vertical thrust is needed from the rear rotor than the front rotor during transition. This is because the flying car tends to move toward a nose-up attitude during transition. A nose-up attitude can be countered by increased vertical thrust toward the rear of the flying car compared to vertical thrust generated toward the front of the flying car. If the second rotor assembly is a dedicated vertical thrust assembly (e.g., fixed for vertical thrust or only allows limited rotor pitch adjustment, e.g., for stability), it may be more suitable for providing increased vertical thrust during transition compared to tilt rotors that can be adjusted in angle, and therefore may be advantageously located further aft on the flying car. In configurations where the first rotor assembly is located further forward on the flying car body than the second rotor assembly, the drag reduction that can be achieved by the absence of an intervening pylon on the second rotor assembly may become more important. This is because the second rotor assembly downstream of the tilt rotor may experience airflow accelerated by the wake. Improved efficiency, dynamic, and / or noise performance (e.g., as may be facilitated by a stacked rotor operating as a single multi-element lifting wing) may also become more important for the same reasons. Alternatively, a tighter overall package (unit) of the second rotor assembly may be enabled, enabling a configuration in which the second rotor assembly is better able to avoid the tilt rotor's wake.

[0013] In some embodiments, the first rotor assembly is positioned so that a predetermined tilt angle exists within the entire tilt angle range of the tilt rotor. The predetermined tilt angle is an angle such that an axis between the center of the tilt rotor and the center point of the stack rotor of the second rotor assembly is substantially perpendicular to a plane of rotation defined by the tilt rotor blades that rotate to provide thrust. When the tilt rotor has a plane of rotation defined by the tilt rotor blades that rotate to provide thrust and that substantially faces the stack rotor, the stack rotor is likely to be subjected to the wake of the tilt rotor. This may occur, for example, during steady flight and / or transitional flight configurations.

[0014] In some embodiments, the first rotor assembly is positioned so that the predetermined tilt angle does not exist within the entire tilt angle range of the tilt rotor. The predetermined tilt angle is an angle such that the axis between the center of the tilt rotor and the center point of the stack rotor of the second rotor assembly is substantially perpendicular to the plane of rotation defined by the tilt rotor blades that rotate to provide thrust. If the tilt rotor does not have a plane of rotation defined by the tilt rotor blades that rotate to provide thrust and that substantially faces the stack rotor, the stack rotor may be less likely to be subjected to the wake of the tilt rotor. This is facilitated by the present invention, which can prevent / reduce turbulence effects that would otherwise occur.

[0015] In some embodiments, the stack rotor (vertical thrust rotor) is mounted to the pylon such that it is positioned substantially above the pylon. Increasing the height of the stack rotor, such as may be facilitated by being located above the pylon, tends to reduce the degree of wake impingement from the upstream tilt rotor, which changes its discharge direction (exhaust direction) between substantially aft and substantially downward and impinges on the stack rotor. Thus, the adverse effects of such impingement (e.g., increased noise and increased blade loading in the stack rotor) may be at least partially mitigated.

[0016] In some embodiments, the second rotor assembly is positioned further forward on the flying car body than the first rotor assembly. Many of the advantages discussed above (e.g., performance advantages of pairing the first and second rotor assemblies) also apply when the stack rotor is further forward than the tilt rotor. Furthermore, while advantages related to the tilt rotor's wake may not apply or may be less relevant, additional advantages may arise. For example, this configuration may facilitate shorter exposure times and / or reduce the probability of blade separation trajectory crossing and rotor cascade failure. Furthermore, this configuration may help balance or mitigate propeller fin effects, which may be generated by one or more other rotors, such as in another example of the multi-pair rotor configuration in the first embodiment, where the first rotor assembly is positioned further forward on the flying car body than the second rotor assembly. The propeller fin effect is a yawing or pitching moment caused by the propeller's normal force. A propeller normal force is generated whenever the propeller is tilted into the airflow, thereby acting as a lifting surface, and is more likely to be generated where tiltrotors are used.

[0017] In some embodiments, the second rotor assembly is configured to provide thrust during at least a portion of the flying car's flight configuration when the tilt rotor of the first rotor assembly is tilted between a substantially vertical flight thrust delivery attitude and a substantially steady flight thrust delivery attitude.

[0018] In some embodiments, multiple stack rotors (vertical thrust rotors) are arranged in multiple (at least some) configurations, each of which functions as a single lifting blade. Thus, for example, multiple stack rotors may operate in a coupled manner, thereby increasing lift and / or delaying stall. The orientation of blades within different stack rotors and the proximity between stack rotors may be such that turbulence from upstream of a pair of stack rotors stimulates airflow downstream of the pair. This may be facilitated, at least in part, by providing multiple stack rotors on one side (the same side) of a second rotor assembly, for example, rather than separated by the second rotor assembly.

[0019] In some embodiments, the plurality of stack rotors (vertical thrust rotors) consists of two stack rotors (vertical thrust rotors).

[0020] In some embodiments, multiple stack rotors (vertical thrust rotors) are driven by the same propulsion unit. Thus, for example, multiple stack rotors may be powered by a single electric motor. This may reduce weight and / or complexity and may be facilitated, at least in part, by providing multiple stack rotors, for example, on one side (the same side) of the second rotor assembly pylon rather than separated by the second rotor assembly pylon.

[0021] In some embodiments, the stack rotors are forwardly rotatably supported by a common bearing set and / or a common bearing race between the stack rotors and the remainder of the second rotor assembly, although in other embodiments, separate bearing sets and / or separate bearing races may be used.

[0022] In some embodiments, multiple stack rotors share one or more other common components (e.g., a common thrust bearing and / or a common rotor orientation locking mechanism for the storage configuration described below).

[0023] In some embodiments, each of the stack rotors comprises two blades, which may simplify storage in a more drag-reducing manner.

[0024] In some embodiments, the flying car comprises a second rotor assembly control system configured to selectively control the deployment of the second rotor assembly to a deployed configuration and the storage of the second rotor assembly to a stored configuration, wherein the deployment causes the multiple stack rotors to rotate relative to the deployed configuration about their respective thrust-generating rotation axes so that the blades of each of the multiple stack rotors are angularly offset from the blades of the other stack rotors, and the storage causes the multiple stack rotors to rotate relative to the stored configuration about their respective thrust-generating rotation axes so that the blades of each of the multiple stack rotors are angularly aligned with the blades of the other stack rotors. This can achieve both increased vertical thrust generated during deployment and reduced drag in the stored configuration when the stack rotors are not being used to generate thrust, especially when there are only two blades per rotor in the stack rotors.

[0025] In some embodiments, the combination of blades across multiple stack rotors in a deployed configuration may be arranged so that the blades are angularly spaced consecutively. Alternatively, however, (at least some) of the blades may not be angularly spaced consecutively. For example, the combination of the blades may form a cross shape, where a first set of opposing segments between the blades have equal angular extents and a second set of opposing segments have different angular extents. This configuration may improve efficiency and noise performance.

[0026] In some embodiments, the multiple stack rotors are in a deployed configuration when driven to generate thrust.

[0027] In some embodiments, in the stowed configuration, the blades (rotor blades) of each of the multiple stacked rotors are substantially aligned with an axis parallel to the longitudinal axis of the flying car. This may mean that the blades (rotor blades) of the stacked rotor present a relatively small total frontal area when the stacked rotor is in the stowed configuration, which may reduce drag. In this way, the total frontal area may be further reduced compared to two similarly aligned rotors that are widely spaced apart. Specifically, when multiple stacked rotors are aligned in this manner and close to each other, and there is a blade twist, there may be at least a partial aerodynamic shroud for one blade adjacent to another blade, apart from the stacked rotor, which may further reduce the total frontal area.

[0028] In some embodiments, the stacked rotors are in a stowed configuration when not being driven to generate thrust. For example, a flying car may be able to generate sufficient lift in steady flight without requiring contributions from the stacked rotors, allowing the second rotor assembly to be stowed to reduce power consumption and drag. Then, upon entering a different flight configuration (e.g., transitional or vertical flight), the second rotor assembly may be deployed to provide power to generate vertical thrust.

[0029] In some embodiments, the tilt rotors of the first rotor assembly are configured to transition by tilting through substantially 90 degrees to alternately provide substantially vertical flight thrust and substantially steady flight thrust. Tilting capability beyond the 90 degree range may also be provided (e.g., to facilitate enhanced deceleration and / or reverse flight modes, and / or to facilitate yawing of the flying car such that one tilt rotor tilts backward while another tilt rotor on the other side of the flying car tilts forward).

[0030] In some embodiments, the tilt rotor of the first rotor assembly is configured to translate either forward or backward relative to the flying car in the vertical thrust configuration of the flying car, and to translate in the opposite direction in the steady flight configuration of the flying car. Thus, for example, in addition to tilting upward for the vertical flight configuration, the tilt rotor can translate backward, which may occur when the upward tilt occurs. If the first rotor assembly is located further forward on the flying car body than the second rotor assembly, a backward translation may be utilized for the vertical thrust configuration. Furthermore, if the second rotor assembly is located further forward on the flying car body than the first rotor assembly, a forward translation may be utilized for the vertical thrust configuration. This feature may be used to reduce the lever arm of the first rotor assembly in the steady flight configuration, which may help reduce the propeller fin effect.

[0031] In some embodiments, at least one of the first rotor assembly and the second rotor assembly is attached to a wing of the flying car. The wing may be substantially centered longitudinally relative to the body of the flying car. For example, the wing may be located close to the center of gravity of the flying car. The wing allows for improved steady-state flight efficiency. The wing may be a convenient mounting location for the first rotor assembly and / or the second rotor assembly in terms of various factors, including efficiency, weight distribution of the flying car, ground clearance, etc. If both the first rotor assembly and the second rotor assembly are attached to a wing, this tends to imply that the first rotor assembly and the second rotor assembly are close to each other. Therefore, even if either the first rotor assembly or the second rotor assembly is located downstream of the other, the importance of the present invention in mitigating the effects of wakes may potentially be greater.

[0032] In some embodiments, the first rotor assembly or the second rotor assembly is mounted to the wing so as to project substantially forward of the leading edge of the wing.

[0033] In some embodiments, the first rotor assembly or the second rotor assembly is mounted to the wing so as to project substantially aft of the trailing edge of the wing.

[0034] In some embodiments, the stack rotors are mounted to lie on substantially the same side of a horizontal plane aligned with the chord line of the blades.

[0035] In some embodiments, the stack rotors are mounted substantially above a horizontal plane aligned with the chord line of the wing, thereby reducing the extent to which the stack rotors are subjected to the tilt rotor wake in at least some flight configurations.

[0036] In some embodiments, the first rotor assembly and the second rotor assembly constitute a pair of rotor assemblies, and the flying car comprises multiple pairs of rotor assemblies according to any of the above-mentioned embodiments (alone or in any combination except when mutually exclusive). In particular, multiple pairs of rotor assemblies may be provided on the wings of the flying car and / or distributed over the entire wings of the flying car. Specifically, for example, four pairs of rotor assemblies may be provided, two pairs on each wing of the flying car. Furthermore, all existing pairs of rotor assemblies may be provided on the wings of the flying car.

[0037] In some embodiments, at least two pairs of rotor assemblies are mounted so that they are laterally offset, which may reduce the likelihood that, in a blade separation event, the blade separation trajectory from either pair of rotor assemblies will intersect with blades from the other pair of rotor assemblies.

[0038] In some embodiments, all rotor assemblies of the flying car are provided as part of the multiple pairs of rotor assemblies.

[0039] In some embodiments, all rotor assemblies of the flying car are mounted on the wings of the flying car.

[0040] In some embodiments, the plurality of pairs of rotor assemblies each have a first rotor assembly that is positioned further forward than a second rotor assembly on the flying car body. In particular, there may be two or four pairs of such rotor assemblies.

[0041] In some embodiments, all pairs of rotor assemblies have a second rotor assembly located further forward on the flying car body than the first rotor assembly, and in particular there may be two or four pairs of such rotor assemblies.

[0042] In some embodiments, the multiple pairs of rotor assemblies include one or more pairs in which the first rotor assembly is located further forward than the second rotor assembly on the flying car body, and one or more pairs in which the second rotor assembly is located further forward than the first rotor assembly on the flying car body. Furthermore, there may be an equal number of rotor assemblies in which the first rotor assembly is located further forward than the second rotor assembly on the flying car body and the second rotor assembly is located further forward than the first rotor assembly on the flying car body. Furthermore, the different types (the former type and the latter type) may be arranged symmetrically with respect to the longitudinal axis of the flying car. This may help to reduce the propeller fin effect (which would be exacerbated if both types were not mixed) while maintaining other advantages of the present invention.

[0043] In some embodiments, the flying car comprises a combination of one or more pairs of the plurality of pairs of rotor assemblies and an additional rotor assembly. The additional rotor assembly may comprise one or more additional tilt rotors and / or one or more additional stack rotors (vertical thrust rotors). For example, rotor assemblies according to the following two examples may be provided. In the first example, four additional rotor assemblies are attached to inner stations of each wing, and each additional rotor assembly comprises a plurality of stack rotors (vertical thrust rotors). In the second example, four additional rotor assemblies are attached to outer stations of each wing, and one rotor assembly at each outer station is attached to protrude substantially forward of the leading edge of the wing, and the other rotor assembly at each outer station is attached to protrude substantially rearward from the trailing edge of the wing.

[0044] In some embodiments, the flying car is an aircraft. The flying car may be an air taxi. The flying car may be a VTOL or short take-off and vertical landing (STOVL) air vehicle. The flying car may have a cockpit and / or a cabin. The flying car may be a passenger aircraft. The flying car may be a manned aircraft. The flying car may be piloted and / or have a pilot on board.

[0045] Within the scope of this application, the various aspects, embodiments, examples, and alternatives, particularly individual features thereof, described in the preceding paragraphs, claims, and / or the following description and drawings, are intended to be understood singly or in any combination. That is, all embodiments and / or features of any embodiment may be combined in any manner and / or in any combination, except where such features are incompatible. Applicant reserves the right to modify the originally filed claims or to submit new claims accordingly, including the right to amend the originally filed claims to depend on and / or incorporate features of other claims in an aspect not originally claimed. [Brief explanation of the drawings]

[0046] One or more embodiments of the present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0047] [Figure 1] 1 shows a side view of an aircraft according to an embodiment of the present invention; [Figure 2] 1 shows a perspective view of an aircraft according to an embodiment of the present invention; [Figure 3] Illustrates an alternative to the present invention that does not benefit from the same advantages. [Figure 4] 1 shows a perspective view of an aircraft according to an embodiment of the present invention; [Figure 5] 1 shows a perspective view of an aircraft according to an embodiment of the present invention; DETAILED DESCRIPTION OF THE INVENTION

[0048] 1 and 2, a flying car (aircraft), for example, a VTOL (vertical take-off and landing) air taxi aircraft, is generally designated by reference numeral 1. The aircraft (flying car) 1 has a longitudinal axis, a transverse axis, and a vertical axis (see reference numeral 3). The aircraft 1 has an airframe 5 and, for example, four pairs of rotor assemblies 7 attached to the airframe 5. The airframe 5 has a fuselage 9, a pair of wings 11, and a tail 13. The centerline of the aircraft 1 and the chord of the wings 11 are aligned along the longitudinal axis. The span direction of the wings 11 is substantially aligned along the transverse axis. The fuselage 9 includes a passenger cabin (not shown) and a cockpit (not shown). However, in other embodiments, the passenger cabin may be omitted or replaced (e.g., with a storage area), and the cockpit may be omitted, particularly when the aircraft 1 is configured for autonomous control or for control from a third-party location (remote location).

[0049] The wings 11 of the aircraft 1 are mounted high on the fuselage 9 (i.e., extending from the top of the fuselage 9) and extend from a longitudinal position substantially coincident with the center of gravity of the aircraft 1. Four pairs of rotor assemblies 7 are attached to the fuselage 5 via the wings 11, two pairs per wing 11. On each wing 11, one pair of rotor assemblies 7 is attached to an inner station 15 at a position approximately one-third of the wing's span, and the other pair of rotor assemblies 7 is attached to an outer station 17 at a position approximately two-thirds of the wing's span.

[0050] Each pair of rotor assemblies 7 includes a first rotor assembly 19 and a second rotor assembly 21. In each pair, the first rotor assembly 19 is disposed further forward on the fuselage 5 of the aircraft 1 than the second rotor assembly 21. Furthermore, in each pair, the first rotor assembly 19 is spaced apart from the second rotor assembly 21 in the longitudinal direction of the aircraft 1. The first rotor assembly 19 and the second rotor assembly 21 are substantially on a vertical plane parallel to a vertical plane aligned with the longitudinal axis of the aircraft 1. In this vertical plane, the first rotor assembly 19 and the second rotor assembly 21 are substantially both on an axis parallel to the longitudinal axis of the aircraft 1.

[0051] An example of the first rotor assembly 19 and its surrounding structure will be described below, but this description will be equally applied to all first rotor assemblies 19 in the multiple pairs of rotor assemblies 7.

[0052] The first rotor assembly 19 includes a tilt rotor 23. The tilt rotor 23 is tiltable through substantially 90 degrees under the influence of a first rotor assembly control system to alternately provide substantially vertical flight thrust and substantially steady flight thrust, with a transition zone between the two thrust delivery configurations. The tilt rotor 23 is attached to the wing 11 at the associated station 15, 17 by a first rotor assembly pylon 25. The first rotor assembly pylon 25 projects forward from and is substantially perpendicular to a leading edge 27 of the wing 11. The tilt rotor 23 is attached adjacent to the distal end of the first rotor assembly pylon 25. The tilt rotor 23 itself therefore projects substantially forward of the leading edge 27 and is positioned in a cantilevered configuration. The tilt mechanism (tilting mechanism) of the tilt rotor 23 moves the tilt rotor 23 when tilting the tilt rotor 23. Specifically, when the tilt rotor 23 tilts toward the vertical thrust supply attitude (vertical thrust supply configuration), the tilt rotor 23 is moved toward the wing 11 to which the tilt rotor 23 is attached (i.e., rearward). Furthermore, when the tilt rotor 23 is tilted toward the steady flight configuration (steady thrust supply attitude), the tilt rotor 23 is moved away from the wing 11 to which the tilt rotor 23 is attached (i.e., forward). The tilt rotor 23 is driven by, for example, an electric motor (not shown).

[0053] An example of the second rotor assembly 21 and its surrounding structure will be described below, but this description will be equally applied to all second rotor assemblies 21 in the multiple pairs of rotor assemblies 7.

[0054] The second rotor assembly 21 includes a plurality of stack rotors (vertical thrust rotors) 29 that are stacked on top of each other to provide thrust in a substantially vertical direction. In this embodiment, the stack rotor 29 is configured by two stacked rotors. The second rotor assembly 21 is attached to the wing 11 at the associated station 15, 17 by a second rotor assembly pylon (pylon for the second rotor assembly) 31. The second rotor assembly pylon 31 projects rearward from a trailing edge 33 of the wing 11 and is substantially perpendicular to the trailing edge 33. The stack rotor 29 is attached adjacent to the tip (distal end) of the second rotor assembly pylon 31. Therefore, the stack rotor 29 itself also projects substantially rearward from the trailing edge 33. The plurality of stack rotors 29 are arranged on the same side of the second rotor assembly pylon 31 (in this embodiment, on the upper side of the second rotor assembly pylon 31). Also, in this embodiment, the stack rotors 29 are mounted substantially above a horizontal plane aligned with the chord line of the wing 11 to which they are attached. The stack rotors 29 are oriented to generate vertical thrust. Thus, each stack rotor 29 lies substantially in its own plane that is substantially parallel to the chord line of the wing 11 to which it is attached.

[0055] The stack rotor 29 is provided to provide substantially only vertical thrust and is therefore not a tilt rotor, although in some embodiments the stack rotor 29 may have some degree of gimbling articulation, for example to allow for moderate stability compensation.

[0056] The multiple stack rotors 29 are identical in configuration and rotate about a common axis to generate thrust. The multiple stack rotors 29 are mounted closely to one another (e.g., the spacing between the multiple stack rotors 29 is substantially less than 100% of the mean aerodynamic chord length of the blades (rotor blades) 35 of the stack rotors 29). The second rotor assembly 21 includes, as a propulsion unit, an electric motor (not shown) that drives the multiple stack rotors 29 in the same rotational direction to generate thrust.

[0057] Each stack rotor 29 comprises two blades 35. The two blades 35 extend in opposite directions and each have a blade twist. In FIGS. 1 and 2, the second rotor assembly 21 is shown in a stowed configuration. In the stowed configuration, the blades 35 of each stack rotor 29 are angularly aligned with the other blades 35 and do not rotate, thus not providing vertical thrust. Furthermore, the blades 35 are substantially aligned with an axis parallel to the longitudinal axis of the aircraft 1 and are held in this position (e.g., using appropriate stops, detents, clutches, etc.). The second rotor assembly control system can control the relative rotation between the rotors of the two stack rotors 29 about the thrust-generating axis of rotation, all the way to the deployed configuration. In the deployed configuration, the blades 35 of each stack rotor 29 are angularly offset from the other blades 35. In particular, the relative rotation occurs through substantially 90 degrees. Thus, the combination of the two stack rotors 29 provides a four-blade system in which all four blades 35 are equally angularly spaced. The second rotor assembly control system can then return the second rotor assembly 21 to the stacked (stored) configuration by further appropriate relative rotation between the stack rotors 29. The second rotor assembly control system may include any suitable system for coordinating between the stored and deployed configurations (e.g., the system may utilize electrical power to release, lock, and / or actuate relative rotation between the stack rotors 29, use steady (horizontal) flight airflow to passively effect relative rotation between the stack rotors 29, or use blade inertia and / or braking forces selectively applied to one or the other stack rotor 29 to effect relative rotation between the stack rotors 29).

[0058] In use, the aircraft 1 is capable of operating in steady (horizontal) flight, transitional (transitional) flight, and vertical flight, and has different configurations for each of these flight modes.

[0059] During steady flight, the required lift is provided by the wings 11 and thrust is supplied by the tilt rotors 23 (controlled by the first rotor assembly control system based on instructions from the flight controller) as configured in steady flight mode. Note that in steady flight mode, the planes of the tilt rotors 23's blades are aligned substantially vertically. In this configuration, turbulence from the tilt rotors 23 in each pair of rotor assemblies 7 acts on the stack rotors 29 of the second rotor assembly 21 of the same pair. However, during steady flight, the flight controller controls the second rotor assembly control system to place the second rotor assembly 21 in a stowed configuration. The resulting alignment of the blades 35 of the stack rotors 29 with an axis parallel to the longitudinal axis of the aircraft 1 means that the total frontal area of ​​the stack rotors 29 relative to the airflow and the turbulence from the tilt rotors 23 are relatively small in steady flight. Furthermore, due to the proximity of the two stack rotors 29 and the blade twist of the blades 35 of the stack rotors 29, one stack rotor 29 is partially blocked by the other stack rotor 29. This reduces the total frontal area compared to a theoretical scenario in which the two stack rotors 29 are aligned as described above but are significantly spaced apart (e.g., by a pylon supporting them). As a result, the drag and noise generated by the second rotor assembly 21 when not in use during steady flight may be reduced.

[0060] However, the present invention is not limited to the above configuration, and in other embodiments, the stack rotor 29 may be positioned so as to substantially exceed the turbulence from the tilt rotor 23 when the tilt rotor 23 is in a steady flight configuration. Such a positioning can be easily achieved by placing the stack rotor 29 close to one side of the second rotor assembly pylon 31.

[0061] When it is desired to enter vertical flight, the flight controller begins adjusting the configuration of the aircraft 1 from a steady-state flight configuration to a vertical flight configuration. Between the steady-state flight configuration and the vertical flight configuration, the aircraft 1 is in a transition configuration and performs a transitional flight. When a transition from steady flight to vertical flight occurs, the transitional configuration and the transitional flight are characterized by a steady decrease in steady-state flight thrust (i.e., forward flight thrust) when the flight controller instructs the first rotor assembly control system to adjust the pitch of the tilt rotor 23 to a vertical flight configuration (i.e., a configuration in which the blade planes of the tilt rotor 23 are aligned substantially horizontally). Furthermore, the transitional configuration and the transitional flight are characterized by a steady decrease in steady-state flight thrust (i.e., forward flight thrust) when, under the control of the flight controller, the second rotor assembly control system moves the stack rotor 29 to a deployed configuration and actuates the stack rotor 29 to provide vertical thrust, resulting in a decrease in lift provided by the wings 11 and an increase in vertical thrust provided by the tilted tilt rotor 23 and stack rotor 29. As the tilt rotors 23 are tilted towards their vertical flight configuration, they are translated aft towards the wings 11 and first rotor assembly pylon 25 to which they are attached. This allows for a reduction in lever arm for each tilt rotor 23, which may reduce propeller fin effect forces experienced during the transition configuration.

[0062] During part of the transition, the stack rotors 29 are in operation (providing vertical thrust), but each stack rotor 29 is still subject to the wake 37 of its upstream tilt rotor 23 until the tilt rotors 23 are tilted sufficiently that the wake 37 is no longer significant. However, because the stack rotors 29 are in close proximity to each other and positioned above the second rotor assembly pylon 31, the duration for which they are subject to the wake 37 may be reduced compared to alternative configurations.

[0063] Given the close proximity of the stack rotors 29 to one another, the stack rotors 29 effectively form a single lifting airfoil of four blades (in this example) when in the deployed configuration, which may result in increased efficiency and reduced noise compared to a situation where the stack rotors 29 were spaced a greater distance apart (e.g., as forced by an intervening pylon).

[0064] Once in vertical flight mode, the aircraft 1 can be operated to hover, ascend vertically, or descend vertically (e.g., for vertical takeoff and landing) by appropriately adjusting the thrust generated by the tilt rotor 23 and stack rotor 29.

[0065] When it is desired to re-enter steady flight, the transition process described above can be performed in reverse. This transition process involves the tilt rotor 23 extending (i.e., translating forward) as it tilts toward the steady flight configuration. It is further noted that in at least some embodiments, the transition configuration can be maintained as a stable configuration. For example, the tilt rotor 23 can be maintained at a tilt angle selected from among possible tilt angles between the steady flight configuration and the vertical flight configuration. Furthermore, the stack rotor 29 can be stowed and deactivated or deployed and activated to generate thrust according to given parameters required for vertical thrust, such as airspeed and tilt rotor 23 angle.

[0066] The embodiment of Figures 1 and 2 may have several advantages over the configuration shown in Figure 3, for example. The configuration of Figure 3 is substantially similar to the configuration of Figures 1 and 2, but rather than the stack rotor 29 being disposed on a second rotor assembly pylon 31, the configuration of Figure 3 utilizes two stack rotors (vertical thrust rotors or vertical rotors) 41 spaced more widely apart, each mounted on one side of a supporting pylon 43. This may mean that the stack rotors 41 are exposed to the wake 45 of the upstream tilt rotor 47 during most of the steady and transitional flight modes, which may adversely affect performance and noise. Furthermore, stowing the stack rotors 41 when not in use does not provide the benefit of one rotor obscuring a portion of the other rotor to reduce the total frontal area, and therefore may only achieve limited drag reduction. Furthermore, the spacing between the stack rotors 41 means that the stack rotors 41 do not collectively function as a single multi-element lifting wing, which could provide potential efficiency, dynamic, and noise benefits. It is also prone to blade vortex interaction between the stack rotors 41. Furthermore, the configuration of Figure 3 makes it more difficult to obtain opportunities for sharing components (e.g., drive motors, bearings, and / or bearing races, etc.), which may increase weight and complexity.

[0067] The present invention allows for alternative embodiments, and Figures 4 and 5 show two examples of such alternative embodiments. The embodiment of Figure 4 shows an aircraft 51 that is broadly similar to that described above with respect to Figures 1 and 2. It differs from the embodiment with respect to Figures 1 and 2 in that the aircraft 51 has four pairs of rotor assemblies 53 instead of the four pairs of rotor assemblies 7 described above. In the rotor assembly 53, the positions of the first and second rotor assemblies are reversed compared to the rotor assembly 7 described above. Thus, in Figure 4, the second rotor assembly (stack rotor) is located forward of the first rotor assembly (tilt rotor). In this embodiment, the first rotor assembly is a pusher, tilting downward (rather than upward) to provide vertical thrust.

[0068] The embodiment of FIG. 5 illustrates an aircraft 61 broadly similar to that described above with reference to FIGS. 1 and 2. Unlike the embodiment of FIGS. 1 and 2, the aircraft 61 includes only two pairs of similar rotor assemblies 63 at the inner station 65, rather than the four pairs of rotor assemblies 7 described above. The outer station includes two pairs of rotor assemblies 67, each of which includes two elements of the second rotor assembly 21 (i.e., a stack rotor forward of the leading edge 69 of the wing 71 and a stack rotor aft of the trailing edge 73 of the wing 71). Given that the embodiment of FIG. 5 has only two tilt rotors, it is less susceptible to excessive propeller fin effect, which may also result in weight savings. This embodiment also retains the advantages of the pair of rotor assemblies 67 described above with reference to the embodiment of FIGS. 1 and 2. The displaced second rotor assembly 21 may provide additional vertical thrust for vertical flight configurations, if desired.

[0069] All structures disclosed in this specification (including the accompanying claims, abstract, and drawings), and / or all steps of any method or process so disclosed, may be combined in any manner, except combinations in which at least some of such structures and / or steps are mutually exclusive.

[0070] Each feature disclosed in this specification (including the accompanying claims, abstract, and drawings), unless expressly stated otherwise, may be replaced by an alternative feature serving the same, equivalent, or similar purpose. Thus, unless expressly stated otherwise, each disclosed feature is only one example of a generic series of equivalent or similar features.

[0071] The invention is not limited to the details of the above-described embodiments. The invention extends to any novel one or combination of features, or any novel one or combination of steps of any method or process disclosed herein (including the accompanying claims, abstract, and drawings). The claims should not be construed to cover only the above-described embodiments, but also to any embodiment that falls within the scope of the claims.

Claims

1. A flying car comprising a first rotor assembly, a second rotor assembly, and a pylon for the second rotor assembly configured to attach the second rotor assembly to a remaining part of the flying car excluding the first rotor assembly and the second rotor assembly, The first rotor assembly and the second rotor assembly are arranged so as to be spaced apart in the longitudinal direction of the flying car and to be positioned in the same vertical plane parallel to the longitudinal axis of the flying car, The first rotor assembly is disposed forward on the body of the flying car compared to the second rotor assembly, the first rotor assembly includes a tilt rotor configured to tilt between a vertical flight thrust supply configuration and a steady flight thrust supply configuration; the second rotor assembly includes a plurality of stack rotors stacked together to provide vertical thrust; the plurality of stack rotors are attached only to an upper side of the pylon; within the tilting range of the tilt rotor, there is no tilt angle at which a rotation plane defined by blades of the tilt rotor that rotates to supply thrust faces the plurality of stack rotors; Flying car.

2. The flying car according to claim 1, wherein the first rotor assembly and the second rotor assembly are arranged so as to be positioned on a single axis parallel to the longitudinal axis.

3. 3. The flying car according to claim 1 or 2, wherein a spacing between the plurality of stack rotors of the second rotor assembly is smaller than 100% of a mean aerodynamic chord length of the blades of the stack rotors.

4. the first rotor assembly is arranged so that no predetermined tilt angle exists within the entire range of tilt angles of the tilt rotor; The predetermined tilt angle is The flying car according to any one of claims 1 to 3, wherein an axis between a center of the tilt rotor and a center point of the stack rotor of the second rotor assembly is angled perpendicular to a plane of rotation defined by the blades of the tilt rotor that rotate to supply thrust.

5. 5. The flying car according to any one of claims 1 to 4, wherein the second rotor assembly is configured to provide thrust during at least a part of a flight configuration of the flying car in which the tilt rotor of the first rotor assembly is tilting between a vertical flight thrust supply attitude and a steady flight thrust supply attitude.

6. The arrangement of the blades of the plurality of stack rotors has a plurality of configurations including a deployed configuration in which the blades of each stack rotor are angularly offset from the blades of the other stack rotors, and a stored configuration in which the blades of each stack rotor are angularly aligned with the blades of the other stack rotors. The flying car according to any one of claims 1 to 5.

7. The flying car according to any one of claims 1 to 6, wherein the plurality of stack rotors are driven by the same propulsion unit.

8. The flying car according to any one of claims 1 to 7, wherein the plurality of stack rotors are supported so as to be rotatable for propulsion by a common bearing set and / or a common bearing race between the plurality of stack rotors and a remaining portion of the second rotor assembly excluding the plurality of stack rotors.

9. the flying car comprises a second rotor assembly control system configured to selectively control deployment of the second rotor assembly into the deployed configuration and storage of the second rotor assembly into the stored configuration; the deployment causes the plurality of stack rotors to rotate relatively about their respective thrust generating rotation axes until the deployed configuration is reached in which the blades of each of the plurality of stack rotors are angularly offset from the blades of the other stack rotors; The flying car according to any one of claims 1 to 8, wherein said storing causes said plurality of stack rotors to rotate relatively about their respective thrust generating rotation axes until said plurality of stack rotors reach said stored configuration in which the blades of each of said plurality of stack rotors are angularly aligned with the blades of other stack rotors.

10. 10. The flying car according to claim 9, wherein in the stored configuration, the blades of each of the plurality of stack rotors are aligned with an axis parallel to a longitudinal axis of the flying car.

11. The flying car according to claim 9 or claim 10, wherein the plurality of stack rotors are in the stored form when not being driven to generate thrust.

12. the tilt rotor of the first rotor assembly is configured to translate backward relative to the flying car when the flying car tilts towards the vertical thrust configuration, and to translate in a direction opposite to the translation direction when the flying car tilts towards the vertical thrust configuration when the flying car tilts towards the steady flight configuration; The flying car according to any one of claims 1 to 11.

13. The flying car according to any one of claims 1 to 12, wherein at least one of the first rotor assembly and the second rotor assembly is attached to a wing of the flying car.

14. The flying car according to any one of claims 1 to 13, wherein the first rotor assembly is attached to a wing of the flying car so as to protrude forward from a leading edge of the wing.

15. The flying car according to any one of claims 1 to 14, wherein the second rotor assembly is attached to the wing so as to protrude rearward from a trailing edge of the wing of the flying car.

16. the first rotor assembly and the second rotor assembly constitute a rotor assembly pair, The flying car according to any one of claims 1 to 15, wherein the flying car comprises a plurality of pairs of the rotor assemblies.

17. The flying car according to claim 16, wherein all rotor assemblies in the flying car are provided as part of the pair of rotor assemblies.

18. The flying car according to claim 16 or claim 17, wherein all rotor assemblies in the flying car are provided on wings of the flying car.

19. The flying car according to any one of claims 1 to 18, which is a VTOL or STOVL aircraft.

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