阅读说明：本技术 具有混合推进的飞行器 (Aircraft with hybrid propulsion ) 是由 F·詹尼尼 于 2021-03-19 设计创作，主要内容包括：公开了具有混合推进的飞行器。公开了用于飞行器的实例推进系统。推进系统包括发动机、电动机、安装至飞行器的空气动力主体的第一螺旋桨——该第一螺旋桨由发动机驱动、安装至空气动力主体且相对于第一螺旋桨定位在外侧的第二螺旋桨——该第二螺旋桨由电动机驱动、以及控制推进系统是否以其中第一螺旋桨和第二螺旋桨被驱动的混合模式运行的选择器。(An aircraft with hybrid propulsion is disclosed. Example propulsion systems for aircraft are disclosed. The propulsion system comprises an engine, an electric motor, a first propeller mounted to an aerodynamic body of the aircraft, the first propeller being driven by the engine, a second propeller mounted to the aerodynamic body and positioned externally with respect to the first propeller, the second propeller being driven by the electric motor, and a selector controlling whether the propulsion system operates in a hybrid mode in which the first propeller and the second propeller are driven.)

1. A propulsion system (300) for an aircraft (100), the propulsion system comprising:

an engine (202);

an electric motor (318);

a first propeller (208) mounted to an aerodynamic body (104) of the aircraft, the first propeller being driven by the engine;

a second propeller (210) mounted to the aerodynamic body and positioned outboard with respect to the first propeller, the second propeller being driven by the electric motor; and

a selector (322) that controls whether the propulsion system is operating in a hybrid mode in which the first and second propellers are driven.

2. The propulsion system of claim 1, wherein the selector includes a selective hybrid propulsion drive train (206).

3. A propulsion system according to claim 1 or claim 2, wherein the second propeller is mounted to an interchangeable propeller assembly (402), the interchangeable propeller assembly (402) being removably coupled from the aerodynamic body via a mechanical connector.

4. The propulsion system according to any of the preceding claims, wherein at least one of the first propeller or the second propeller is foldable.

5. The propulsion system of any of the preceding claims, further comprising a generator (204) operably coupled between the electric motor and the engine.

6. The propulsion system of claim 5, further comprising a battery (320) operably coupled between the generator and the motor, wherein the battery is trickle charged by the generator.

7. The propulsion system of claim 5, further comprising a tiltrotor (108) operably coupled to the generator.

8. A method of providing propulsion to an aircraft, the method comprising:

a first propeller driving the aerodynamic body via the engine; and

selectively driving a second propeller of the aerodynamic body via at least one electric motor based on whether the aircraft is operating in a hybrid mode, the second propeller being located outboard of the first propeller.

9. The method of claim 8, further comprising folding the second propeller toward a respective interchangeable propeller assembly when the second propeller is stopped.

10. The method of claim 8 or claim 9, further comprising enabling the hybrid mode in response to at least one of hovering, takeoff, or landing of the aircraft.

11. The method according to any one of claims 8-10, further comprising trickle charging a battery operatively coupled to the at least one electric motor.

12. The method of any one of claims 8 to 11, further comprising removing an interchangeable propeller assembly from the aircraft to change a flight mode of the aircraft, the interchangeable propeller assembly including one of the second propellers.

13. A propulsion system for a tilted wing of an aircraft, the propulsion system comprising:

a wing body;

a first propeller mounted on the tilted wing, the first propeller being driven by an engine;

a second propeller mounted on the tilted wing, the second propeller positioned outboard relative to the first propeller, the second propeller being driven by at least one electric motor; and

a selector to control whether the propulsion system is operating in a hybrid mode in which the first and second propellers are driven.

14. The propulsion system of claim 13, further comprising a generator operably coupled between the at least one electric motor and the engine.

15. The propulsion system of claim 14, further comprising a battery operably coupled between the generator and the at least one electric motor.

16. The propulsion system of claim 15, wherein the battery comprises a first battery operably coupled to a first one of the second propellers, and further comprising a second battery operably coupled to a second one of the second propellers.

17. The propulsion system of any one of claims 14 to 16, further comprising a tiltrotor operably coupled to the generator.

18. The propulsion system according to any one of claims 13 to 17, wherein the second propellers are mounted to respective interchangeable propeller assemblies that are removably coupled from the tilted wings via mechanical connectors.

19. The propulsion system according to claim 17 or claim 18, wherein the second propeller is foldable relative to the respective interchangeable propeller assembly.

20. A propulsion system according to any of claims 13 to 19, wherein the wing body extends through a fuselage (102) of the aircraft.

Technical Field

The present disclosure relates generally to aircraft, and more particularly to aircraft with hybrid propulsion.

Background

Vertical take-off and landing (VTOL) aircraft have become increasingly popular in recent years in areas where take-off and landing are limited to relatively small areas and/or distances. Accordingly, some known VTOL aerial vehicles employ tilted wings that extend through the fuselage and rotate relative to the fuselage to change the direction of thrust.

Disclosure of Invention

An example propulsion system for an aircraft includes an engine, an electric motor, a first propeller mounted to an aerodynamic body of the aircraft, the first propeller being driven by the engine, a second propeller mounted to the aerodynamic body and positioned outboard relative to the first propeller, the second propeller being driven by the electric motor, and a selector that controls whether the propulsion system is operating in a hybrid mode in which the first and second propellers are driven.

An example method of providing propulsion to an aircraft includes driving a first propeller of an aerodynamic body via an engine, and selectively driving a second propeller of the aerodynamic body via at least one electric motor, the second propeller positioned outboard of the first propeller, based on whether the aircraft is operating in a hybrid mode.

An example propulsion system for a tilted wing of an aircraft includes a wing body, a first propeller mounted on the tilted wing, the first propeller to be driven by an engine, a second propeller mounted on the tilted wing, the second propeller positioned outboard with respect to the first propeller, the second propeller to be driven by at least one electric motor, and a selector that controls whether the propulsion system is operating in a hybrid mode in which the first and second propellers are driven.

Drawings

Fig. 1A and 1B illustrate an example aircraft during hover and cruise, respectively, in accordance with the teachings of the present disclosure.

FIG. 2 is a perspective view of the example aircraft of FIG. 1.

FIG. 3 illustrates an example hybrid propulsion system of the example aircraft of FIGS. 1A-2.

Fig. 4A and 4B illustrate component interchangeability that may be implemented in embodiments disclosed herein.

FIG. 5 is a flow diagram representing an example method of performing embodiments disclosed herein.

FIG. 6 is a flow chart representing an example method of producing embodiments disclosed herein.

FIG. 7 is a flow diagram representing an example method of implementing embodiments disclosed herein.

The figures are not drawn to scale. Rather, the thickness of layers or regions may be exaggerated in the figures. Generally, the same reference numbers will be used throughout the drawings and the following written description to refer to the same or like parts. As used in this patent, any element is said to be in any way on (e.g., positioned on, located on, disposed on, or formed on, etc.) another element, indicating that the referenced element is either in contact with the other element, or that the referenced element is on the other element with one or more intervening element(s) therebetween. Unless otherwise indicated, connection references (e.g., attached, coupled, connected, and engaged) are to be construed broadly and may include intermediate members between a set of elements and relative movement between elements. Thus, joinder references do not necessarily infer that two elements are directly connected and in fixed relation to each other. The statement that any part is "in contact" with another part means that there are no intervening parts between the two parts.

The descriptors "first", "second", "third", etc. are used herein when identifying a plurality of elements or components that may be referenced individually. Unless otherwise specified or understood based on their context of use, such descriptors are not intended to be given any meaning of priority, physical order, or arrangement in a list or temporal order, but merely serve as labels referring individually to a plurality of elements or components to facilitate understanding of the disclosed embodiments. In some embodiments, the descriptor "first" may be used to refer to an element in a particular description, while different descriptors such as "second" or "third" may be used in the claims to refer to the same element. In such instances, it should be understood that such descriptors are merely used to facilitate referencing a plurality of elements or components.

Detailed Description

An aircraft with hybrid propulsion is disclosed. Some known vertical take-off and landing (VTOL) aircraft implement tilted wings for hover operations. In particular, the tilting wings, which pivot with respect to the respective fuselage, are rotated to change the direction of the thrust. Typically, the tilted wing includes an array of propellers mounted thereto and the propellers are typically spaced along the spanwise length of the tilted wing and are driven by the engine and/or turbomachine. Propellers typically require a transmission component that spans the spanwise length of the oblique wing. Therefore, increasing the number of propellers generally requires implementing multiple engines and/or increasing the amount of drive shafts implemented for the transmission. Typically, the propellers are driven during all phases of operation of the aircraft (e.g., takeoff, landing, hovering, transition, and cruise).

Embodiments disclosed herein utilize hybrid propulsion to achieve fuel efficiency and relatively lightweight aircraft. Further, embodiments disclosed herein may reduce push complexity, thereby reducing production and part costs, as well as part count to improve production efficiency. Embodiments disclosed herein may also more efficiently transfer mechanical power generated by the engine by reducing power transmission distances and/or spans. Embodiments disclosed herein utilize a tilted wing having a first propeller driven by an engine and a second propeller driven by at least one electric motor. The second propeller is positioned outboard (e.g., outboard of the fuselage) with respect to the first propeller. The second propeller being electrically driven instead of being driven by the engine described above greatly reduces the mechanical complexity and, thus, the cost of the entire propulsion system. The example second propeller may be stopped and/or driven at a reduced power to conserve and/or enable energy storage when the aircraft is in cruise operation or cruise mode. In some embodiments disclosed herein, the inboard propeller (i.e., the propeller closer to the fuselage) is primarily utilized during cruise, while the outboard propeller (i.e., the propeller further from the fuselage) is primarily used for hover and transition operations.

In some embodiments, the second propellers are folded towards their respective nacelles and/or engine blocks during cruise (e.g., the second propellers are foldable), thereby reducing the drag coefficient of the aircraft. In some embodiments, a generator is operably coupled between the motor(s) and the engine. In some such embodiments, a battery may be operably coupled between the generator and the motor(s). For example, the battery powers the second propeller during take-off and landing, and thus, the engine may be implemented with reduced size and power requirements. In some embodiments, the battery may be trickle charged by the generator (e.g., during cruising).

As used herein, the term "tilt wing" refers to an assembly, device, and/or component that defines a wing body that rotates relative to the fuselage of an aircraft. The wing body may comprise a single wing body extending through the fuselage or a plurality of wing bodies extending from the fuselage. As used herein, the term "aerodynamic body" refers to a fixed wing, a tilt rotor, a variable pitch, a tilt wing, and the like. As used herein, the terms "motor pod" and "interchangeable propeller assembly" refer to interchangeable parts and/or components that include at least a propeller and a motor. The interchangeable parts and/or components may also include a speed controller and are typically removably (e.g., detachably, etc.) coupled to/from the aerodynamic body and/or the wing. As used herein, the term "propeller" refers to a rotor, a fan, or any other suitable thrust device. As used herein, the term "engine" refers to an internal combustion engine, such as a jet engine, a gas engine, and the like.

FIGS. 1A and 1B illustrate an example aircraft 100 during hover and cruise operations, respectively, in accordance with the teachings of the present disclosure. FIG. 1A depicts an example aerial vehicle 100 in hover and/or lift-off mode. The aircraft 100 of the illustrated embodiment includes a fuselage 102 having a cockpit 103, tilted wings (e.g., rotatable tilted wings, rotatable hovering wings, full width tilted wings, etc.) 104 having respective tilt actuators 105, a straight tail wing 106, and a pitch fan (e.g., electric pitch fan) 108. Although in this embodiment the aircraft 100 is manned, the aircraft 100 is alternatively embodied as an Unmanned Aerial Vehicle (UAV). Further, for example, the aircraft 100 may be embodied as a vertical take-off and landing (VTOL) aircraft, a short take-off and landing (STOL) aircraft, or a conventional take-off and landing (CTOL) aircraft.

In operation, the tilt wing 104 is rotatable about the tilt actuator 105 and the fuselage 102 to affect the direction of thrust, and thus the direction of motion of the aircraft 100. In the view shown in fig. 1A, tilted wing 104 is shown oriented in a substantially vertical direction relative to the ground to move aircraft 100 in a relatively upward direction for vertical takeoff or landing. In other words, the tilt wing 104 may be implemented for hover operation or vertical takeoff.

In the illustrated embodiment, a straight tail fin 106 and a pitch fan 108 are positioned at the tail or distal end of fuselage 102 to facilitate stabilization of aircraft 100 during hover or takeoff operation. The example pitch fan 108 controls the pitch of the aircraft 100 and, thus, the orientation of the aircraft 100 relative to the ground. In particular, the negative pitch produced by pitch fan 108 (e.g., the nose of the aircraft is pointed downward relative to the ground) counteracts the positive pitch produced by tilted wing 104 (e.g., the nose of the aircraft is pointed upward relative to the ground) in order to stabilize aircraft 100. In some embodiments, pitch fan 108 is operated to resist undesired rotation and/or instability during VTOL operation. In some embodiments, pitch fan 108 is removed (e.g., interchangeably removed) to configure aircraft 100 for CTOL flight.

FIG. 1B illustrates the example aircraft 100 shown in FIG. 1A in cruise operation. In the illustrated embodiment, the tilted wing 104 is oriented in a relatively horizontal direction with respect to the ground. Thus, the tilted wings 104 generate thrust substantially parallel to the spanwise length of the fuselage 102, and in turn propel the aircraft 100 in a forward direction (e.g., for cruise of the aircraft 100). In this embodiment, the aforementioned pitch fans 108 are shut down and/or turned off when the aircraft 100 is in cruise.

FIG. 2 is a perspective view of the example aircraft 100 of FIGS. 1A and 1B, with the exterior surfaces shown as transparent to depict interior components. In the illustrated embodiment, the aircraft 100 includes an engine 202, a generator 204, a transmission (e.g., a mechanical transmission) 206, a first propeller (e.g., an inboard propeller) 208, and a second propeller (e.g., an outboard propeller) 210 mounted on the tilted wing 104.

In the illustrated embodiment, the engine 202 is positioned within the fuselage 102 and serves as the primary propulsion power unit for the aircraft 100. In particular, the example engine 202 is implemented as a gas turbine engine that drives a transmission 206 and, in turn, a first propeller 208. However, the engine 202 may be embodied as any other suitable type of engine including, but not limited to, a piston engine, a jet engine, a diesel engine, and the like. Although in this embodiment, the example aircraft 100 has a single engine 202, the aircraft 100 may alternatively include multiple engines. Further, any other suitable type of transmission, movement device and/or system may alternatively be implemented.

In the embodiment illustrated in fig. 2, the generator 204 is positioned within the fuselage 102 and is implemented to transmit the energy generated by the engine 202 to the electrical components of the aircraft 100. However, in some other embodiments, the aircraft 100 may alternatively implement multiple ones of the generators 204.

In the embodiment illustrated in fig. 2, the transmission 206 is positioned within the tilted wing 104 and extends generally along the spanwise length of the tilted wing 104 between the first propellers 208. In particular, the span of the example transmission 206 depends on the relative position of the first propellers 208 with respect to each other. In some embodiments, a plurality of pairs of first propellers 208 are positioned on the tilted wing 104 and the transmission 206 extends between the outermost pair of first propellers 208.

In the embodiment illustrated in FIG. 2, the first propeller 208 is mounted to and/or positioned on the tilted wing 104, and the tilted wing 104 is shaped as a generally continuous body (e.g., a continuous aerodynamic body). The example second propeller 210 is folded and positioned outboard of the tilted wing 104 relative to the first propeller 208. In particular, a first propeller 208 and a second propeller 210 are placed in pairs on the tilt wing 104, wherein the second propeller 210 is further from the fuselage 102 than the first propeller 208. However, in some other embodiments, the tilt wing 104 is implemented as a plurality of rotating bodies rather than a single rotating body.

FIG. 3 illustrates an example hybrid propulsion system 300 of the example aircraft 100 shown in FIGS. 1A-2. The example hybrid propulsion system 300 moves the aircraft 100 during both flight (e.g., cruise) and hover operations. As seen in fig. 3, hybrid propulsion system 300 is shown having pitch fan 108, engine 202, generator 204, transmission 206, first propeller 208, and second propeller 210. The hybrid propulsion system 300 further includes an output shaft (e.g., engine drive shaft, engine output shaft, etc.) 302, gear interfaces (e.g., gearbox, differential, etc.) 304, 306, 308, a drive shaft 310 (e.g., transverse drive shaft), a propeller drive shaft 312, gears 314, 316, an electric motor 318, a battery 320, and a selector (e.g., selective hybrid propulsion drive train, selective controller, selection mechanism, etc.) 322.

To drive the first propeller 208 via the propeller drive shaft 312, the engine 202 rotates the output shaft 302, and in turn, the drive shaft 310 via the gear interface 308. In the illustrated embodiment, the drive shaft 310 is oriented perpendicular to the output shaft 302 and extends lengthwise along the tilt wing 104 to transmit mechanical motion of the engine 202 to the propeller drive shaft 312 and, thus, to the first propeller 208. In particular, the gears 314 translate the rotational movement of the drive shaft 310 to the gears 316 via the respective gear interfaces 306, thereby causing the propeller drive shaft 312 to rotate the first propeller 208. In some embodiments, a clutch is implemented to change the engagement between the first gear 314 and the second gear 316. According to the embodiments disclosed herein, only the two innermost propellers 208 are mechanically driven, and the battery 320 is mounted on the opposite outer portion of the wing or tail, thus eliminating most shafting due to the relatively local electric power device. Therefore, the entire shafting length can be relatively short. Conversely, excessive mechanical gearing increases the demands on the wiring harness and shafting. Thus, the power source distribution of the embodiments disclosed herein reduces the weight, wiring harness, and/or transmission required. As one of ordinary skill in the art will appreciate, the allocation of an electric powertrain (e.g., using battery 320) to the propulsion units (i.e., propellers), which are located further from the power source than those having a mechanical or electromechanical powertrain, is not limited to being applicable to a particular number or grouping of propulsion units, or any variation thereof.

To drive the second propeller 210, the generator 204 is operatively coupled to the engine 202 via the gear interface 304 to provide electrical power to the motor 318. In some embodiments, the generator 204 is electrically coupled to the pitch fan 108 in addition to the motor 318. In this embodiment, the battery 320 stores the energy provided by the generator 204 for later use by the corresponding motor 318. In some such embodiments, the battery 320 may be trickle charged by the generator 204. However, in other embodiments, the battery 320 is not implemented. The example selector 322 controls whether power from the generator 204 and/or the battery 320 is provided to the motor 318 (e.g., controls whether the second propeller is driven or stopped).

In the embodiment illustrated in FIG. 3, the example hybrid propulsion system 300 changes the aircraft 100 between hover and cruise operations and/or modes. In this embodiment, during takeoff/landing or hover modes, the tilt wing 104 rotates relative to the fuselage 102 (as shown in fig. 1A-2) to achieve a substantially vertical orientation. In this mode of operation, the power generated by the engine 202 drives the first propeller 208, while the selector 322 enables the electrical energy provided by the generator 204 and/or the battery 320 to drive the second propeller 210 until the aircraft 100 reaches or maintains a desired altitude and/or hover condition. In this embodiment, to transition the aircraft 100 to cruise mode once the aircraft 100 reaches or maintains the desired hover altitude, the tilted wing 104 is rotated to a substantially horizontal orientation, and once cruise mode is achieved, the selector 322 turns off and/or shuts down the second propeller 210 and the pitch fan 108 so that the first propeller 208 may be operated for cruise and/or flight. In some embodiments, the second propeller 210 folds toward the respective nacelle and/or engine block during cruise to reduce drag of the aircraft 100.

Turning to fig. 4A and 4B, component interchangeability that may be implemented in embodiments disclosed herein is illustrated. In the embodiment illustrated in fig. 4A, the second propeller 210, the motor 318, and the battery 320 shown in fig. 3 define an interchangeable propeller assembly (e.g., a motor pod, a removable propeller, etc.) 402. The example interchangeable rotor assembly 402 may also include a speed controller to vary the rotational speed of the second rotor 210. In some embodiments, the battery 320 is not included in the interchangeable propeller assembly 402. In the illustrated embodiment, the example aircraft 100 is depicted in a cruise mode with four interchangeable propeller assemblies 402 implemented on the tilted wing 104. In this embodiment, the interchangeable propeller assembly 402 is removably coupled to the tilted wing 104 (e.g., via quick disconnect wiring, a spring loaded connector, and/or a mechanical connector) to change the operating mode of the aircraft 100. In particular, any number of pairs of interchangeable propeller assemblies 402 may be added to or removed from the aircraft 100 depending on the application, needs, and/or desired operation of the aircraft 100.

Turning to FIG. 4B, an example aircraft 100 is shown with interchangeable propeller assembly 402 and pitch fan 108 removed (e.g., temporarily removed). In this embodiment, the aircraft 100 is configured for STOL and/or CTOL operation, wherein the aircraft 100 is propelled by the first propeller 208 in the absence of the second propeller 210. In this embodiment, removing interchangeable propeller assembly 402 and pitch fan 108 significantly reduces the weight of example aircraft 100 and, in turn, increases payload capacity, mission range, and fuel efficiency.

A flowchart representing an example method 500 of operating tiltrotor aircraft 100 is shown in fig. 5. The example method 500 of FIG. 5 begins when the aircraft 100 is deployed and/or is airborne. In the illustrated embodiment, the orientation of tilted wing 104 changes the direction of thrust on aircraft 100, and in turn, changes the direction of flight of aircraft 100.

At block 502, the tilted wing 104 is rotated to a hover orientation. That is, the tilted wing 104 is rotated about the fuselage 102 to a substantially vertical orientation relative to the ground, thereby directing thrust from the first and second propellers 208, 210 to propel the aircraft 100 generally upward.

At block 504, the engine 202 drives the first propeller 208. In particular, the transmission 206 transmits power between the engine 202 and the first propeller 208.

At block 506, at least one of the motors 318 drives the second propeller 210. In particular, at least one of the motors 318 is powered by the generator 204 and/or the battery 320.

At block 508, the first propeller 208 and the second propeller 210 are driven until the aircraft 100 reaches a desired hover state and/or altitude. For hover operation, the example aerial vehicle 100 maintains a desired altitude by driving both the first propeller 208 and the second propeller 210.

At block 510, the tilted wing 104 is rotated to a cruise orientation. In particular, the example tilt wing 104 is rotated relative to the fuselage 102 to a substantially horizontal orientation relative to the ground, thereby directing thrust from the first and second propellers 208, 210 to propel the aircraft 100 in a forward direction.

At block 512, the second propeller 210 is stopped. In some embodiments, power from the generator 204 and/or the battery 320 is no longer provided to the motor 318. In other words, the second propeller 210 is turned off.

At block 514, the second propeller 210 is folded toward the respective motor body and/or nacelle to reduce the drag coefficient of the aircraft 100 during cruise.

At block 516, the battery 320 is charged by the generator 204 when the second propeller 210 is stopped. In this embodiment, the battery 320 is trickle charged during cruise.

A flow chart representing an example method 600 of producing embodiments disclosed herein is shown in fig. 6. The example method of fig. 6 begins with the tilted wing 104 being implemented on the aircraft 100.

At block 602, the first propeller 208 is mounted on the tilted wing 104. In this embodiment, the first propellers 208 are mounted in pairs, with the left and right propellers of each pair being mounted on respective left and right sides of the fuselage 102.

At block 604, the second propellers 210 are mounted on the tilted wings 104 from outside the respective first propellers 208. In some embodiments, the second propeller 210 is removably coupled to the tiltrotor wing 104 and/or is interchangeable with the tiltrotor wing 104.

At block 606, the first propeller 208 is operably coupled to the engine 202.

At block 608, the second propeller 210 is operably coupled to at least one of the respective motors 318.

At block 610, one or more of the batteries 320 are operably coupled to at least one electric motor 318. In some embodiments, battery 320 is not implemented.

At block 612, the generator 204 is operably coupled between the battery 320 and the engine 202. Additionally or alternatively, the generator 204 is operatively coupled between the engine 202 and at least one of the motors 318 (e.g., the second propeller 210 is directly connected (wire) to the generator 204). In some embodiments, the generator 204 is implemented to trickle charge the battery 320.

A flow chart representing an example method 700 of powering the hybrid propulsion system 300 is shown in FIG. 7. The example method 700 of fig. 7 begins with the hybrid propulsion system 300 being deployed. In the illustrated embodiment, the selector 322 controls whether to drive the second propeller 210 based on whether the hybrid propulsion system 300 is operating in a hybrid mode (e.g., simultaneously operating electrically driven and engine driven propellers) or a non-hybrid mode (e.g., separately operating engine driven propellers).

At block 702, the engine 202 drives the first propeller 208. In particular, the transmission 206 transmits power between the engine 202 and the first propeller 208.

At block 704, the selector 322 selects a hybrid operating mode of the hybrid propulsion system 300. In some embodiments, the hybrid mode is selected for hovering, takeoff, and/or landing of the aircraft 100.

At block 706, the selector 322 directs at least one of the motors 318 to drive the second propeller 210. In particular, at least one of the motors 318 is powered by the generator 204 and/or the battery 320.

At block 708, the selector 322 selects a non-hybrid operating mode for the hybrid propulsion system 300. In some embodiments, the non-hybrid mode is selected during cruise of the aircraft 100. In other embodiments, the non-hybrid mode is selected when the interchangeable rotor assembly 402 is removed.

At block 710, the selector 322 directs the second propeller 210 to stop and/or turn off during the non-hybrid mode. In some embodiments, the second propeller 210 is folded when stopped and/or turned off.

At block 712, the battery 320 is trickle charged by the generator 204 when the second propeller 210 is stopped and/or turned off.

The terms "including" and "comprising" (and all forms and tenses thereof) are used herein as open-ended terms. Thus, whenever a claim takes any form of "including" or "comprising" (e.g., including, comprising, having, including, etc.) as a preamble or in the recitation of any kind of claim, it is to be understood that further elements, terms, etc. may be present without falling outside the scope of the respective claim or recitation. As used herein, the phrase "at least" when used as a transitional term in, for example, the preamble of the claims is also open-ended in the same manner in which the terms "comprising" and "including" are open-ended. For example, when used in a format such as A, B and/or C, the term "and/or" refers to any combination or subset of A, B, C, such as: (1) a alone, (2) B alone, (3) C alone, (4) A and B, (5) A and C, (6) B and C, and (7) A and B and C. As used herein in the context of describing structures, components, articles, objects, and/or things, the phrase "at least one of a and B" is intended to refer to implementations that include any of the following: (1) at least one a, (2) at least one B, and (3) at least one a and at least one B. Similarly, as used herein in the context of describing structures, components, articles, objects, and/or things, the phrase "at least one of a or B" is intended to refer to implementations that include any of the following: (1) at least one a, (2) at least one B, and (3) at least one a and at least one B. As used herein in the context of describing the performance or execution of processes, instructions, actions, activities, and/or steps, the phrase "at least one of a and B" is intended to refer to implementations that include any of the following: (1) at least one a, (2) at least one B, and (3) at least one a and at least one B. Similarly, as used herein in the context of describing the performance or execution of processes, instructions, actions, activities, and/or steps, the phrase "at least one of a or B" is intended to refer to implementations that include any of the following: (1) at least one a, (2) at least one B, and (3) at least one a and at least one B.

As used herein, singular references (e.g., "a," "an," "first," "second," etc.) do not exclude a plurality. As used herein, the term "a" or "an" entity refers to one or more of that entity. The terms "a" or "an", "one or more", and "at least one" are used interchangeably herein. Furthermore, although individually listed, a plurality of means, elements or method acts may be implemented by e.g. a single unit or processor. Additionally, although individual features may be included in different embodiments or claims, these features may be combined, and the inclusion in different embodiments or claims does not imply that a combination of features is not feasible and/or advantageous.

Embodiment 1 comprises a propulsion system for an aircraft. The propulsion system comprises an engine, an electric motor, a first propeller mounted to an aerodynamic body of the aircraft, the first propeller being driven by the engine, a second propeller mounted to the aerodynamic body and positioned externally with respect to the first propeller, the second propeller being driven by the electric motor, and a selector controlling whether the propulsion system operates in a hybrid mode in which the first and second propellers are driven.

Embodiment 2 includes the propulsion system as defined in embodiment 1, wherein the selector includes a selective hybrid propulsion drive train.

Embodiment 3 includes the propulsion system as defined in embodiment 1, wherein the second propeller is mounted to an interchangeable propeller assembly which removably couples the aerodynamic body via a mechanical connector.

Embodiment 4 includes the propulsion system as defined in embodiment 1, wherein at least one of the first or second propellers is foldable.

Embodiment 5 includes the propulsion system as defined in embodiment 1, further comprising a generator operably coupled between the motor and the engine.

Embodiment 6 includes the propulsion system as defined in embodiment 5, further comprising a battery operably coupled between the generator and the electric motor, wherein the battery is trickle charged by the generator.

Embodiment 7 includes a propulsion system as defined in embodiment 5, further comprising a tiltrotor operably coupled to the generator.

Embodiment 8 includes a method of providing propulsion to an aircraft. The method includes driving a first propeller of the aerodynamic body via the engine and selectively driving a second propeller of the aerodynamic body via at least one electric motor based on whether the aircraft is operating in a hybrid mode, the second propeller being positioned outboard of the first propeller.

Embodiment 9 includes the method as defined in embodiment 8, further comprising folding the second propeller toward the respective interchangeable propeller assembly when the second propeller is stopped.

Embodiment 10 includes a method as defined in embodiment 8, further comprising enabling a hybrid mode in response to at least one of hovering, takeoff, or landing of the aircraft.

Embodiment 11 includes the method as defined in embodiment 8, further comprising trickle charging a battery operatively coupled to the at least one electric motor.

Embodiment 12 includes the method as defined in embodiment 8, further comprising removing an interchangeable propeller assembly from the aircraft to change a flight mode of the aircraft, the interchangeable propeller assembly including one of the second propellers.

Embodiment 13 includes a propulsion system for a tiltrotor wing of an aircraft. The propulsion system includes a wing body, a first propeller mounted on the tilted wing, wherein the first propeller is driven by an engine, a second propeller mounted on the tilted wing, wherein the second propeller is positioned outboard relative to the first propeller and wherein the second propeller is to be driven by at least one electric motor, and a selector that controls whether the propulsion system is operating in a hybrid mode in which the first and second propellers are driven.

Embodiment 14 includes the propulsion system as defined in embodiment 13, further comprising a generator operably coupled between the at least one electric motor and the engine.

Embodiment 15 includes the propulsion system as defined in embodiment 14, further comprising a battery operably coupled between the generator and the at least one electric motor.

Embodiment 16 includes the propulsion system as defined in embodiment 15, wherein the battery comprises a first battery operably coupled to a first one of the second propellers, and further comprising a second battery operably coupled to a second one of the second propellers.

Embodiment 17 includes the propulsion system as defined in embodiment 14, further comprising a tiltrotor operably coupled to the generator.

Embodiment 18 includes the propulsion system as defined in embodiment 13, wherein the second propellers are mounted to respective interchangeable propeller assemblies removably coupled from the tiltrotor wing via a mechanical connector.

Embodiment 19 includes the propulsion system as defined in embodiment 13, wherein the second propeller is foldable with respect to the respective interchangeable propeller assembly.

Embodiment 20 includes the propulsion system as defined in embodiment 13, wherein the wing body extends through a fuselage of the aircraft.

From the foregoing, it will be appreciated that example methods, apparatus, and articles of manufacture have been disclosed that are cost effective, easy to implement, and can reduce the mechanical complexity of an aircraft. Further, embodiments disclosed herein may reduce the weight of the aircraft and, thus, increase fuel efficiency.

Although certain example methods, apparatus, and articles of manufacture have been disclosed herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus, and articles of manufacture fairly falling within the scope of the appended claims of this patent.

The present disclosure includes the subject matter described in the following clauses:

clause 1. a propulsion system (300) for an aircraft (100), the propulsion system comprising:

an engine (202);

an electric motor (318);

a first propeller (208) mounted to an aerodynamic body (104) of the aircraft, the first propeller being driven by the engine;

a second propeller (210) mounted to the aerodynamic body and positioned outboard with respect to the first propeller, the second propeller being driven by the electric motor; and

a selector (322) to control whether the propulsion system is operating in a hybrid mode in which the first and second propellers are driven.

Clause 2. the propulsion system as defined in clause 1, wherein the selector comprises a selective hybrid propulsion drive train (206).

Clause 3. the propulsion system as defined in clause 1 or clause 2, wherein the second propeller is mounted to an interchangeable propeller assembly (402) removably coupled from the aerodynamic body via a mechanical connector.

Clause 4. the propulsion system as defined in any of the preceding clauses, wherein at least one of the first or second propellers is foldable.

Clause 5. the propulsion system as defined in any of the preceding clauses, further comprising a generator (204) operably coupled between the motor and the engine.

Clause 6. the propulsion system as defined in clause 5, further comprising a battery (320) operably coupled between the generator and the electric motor, wherein the battery is trickle charged by the generator.

Clause 7. the propulsion system as defined in clause 5, further comprising a tiltrotor (108) operably coupled to the generator.

Clause 8. a method of providing propulsion to an aircraft, the method comprising:

a first propeller driving the aerodynamic body via the engine; and is

Selectively driving a second propeller of the aerodynamic body via the at least one electric motor based on whether the aircraft is operating in the hybrid mode, the second propeller being located outboard of the first propeller.

Clause 9. the method as defined in clause 8, further comprising folding the second propeller toward the respective interchangeable propeller assembly when the second propeller is stopped.

Clause 10. the method as defined in clause 8 or clause 9, further comprising enabling the hybrid mode in response to at least one of hovering, takeoff, or landing of the aircraft.

Clause 11. the method as defined in any of clauses 8 to 10, further comprising trickle charging a battery operatively coupled to the at least one electric motor.

Clause 12. the method as defined in any of clauses 8 to 11, further comprising removing the interchangeable propeller assembly from the aircraft to change a flight mode of the aircraft, the interchangeable propeller assembly including one of the second propellers.

Clause 13. a propulsion system for a tilted wing of an aircraft, the propulsion system comprising:

a wing body;

a first propeller mounted on the tilted wing, the first propeller being driven by the engine;

a second propeller mounted on the tilted wing, the second propeller being positioned outboard with respect to the first propeller, the second propeller being driven by at least one electric motor; and

a selector to control whether the propulsion system is operating in a hybrid mode in which the first and second propellers are driven.

Clause 14. the propulsion system as defined in clause 13, further comprising a generator operably coupled between the at least one electric motor and the engine.

Clause 15. the propulsion system as defined in clause 14, further comprising a battery operably coupled between the generator and the at least one electric motor.

Clause 16. the propulsion system as defined in clause 15, wherein the battery comprises a first battery operably coupled to a first one of the second propellers, and further comprising a second battery operably coupled to a second one of the second propellers.

Clause 17. the propulsion system as defined in any of clauses 14 to 16, further comprising a tiltrotor operably coupled to the generator.

Clause 18. the propulsion system as defined in any of clauses 13 to 17, wherein the second propellers are mounted to respective interchangeable propeller assemblies removably coupled from the tilt wing via a mechanical connector.

Clause 19. the propulsion system as defined in clause 17 or clause 18, wherein the second propeller is foldable with respect to the respective interchangeable propeller assembly.

Clause 20. the propulsion system as defined in any one of clauses 13 to 19, wherein the wing body extends through a fuselage (102) of the aircraft.

The claims are incorporated into this specification by reference, with each claim standing on its own as a separate instance of this disclosure.