Vertical takeoff and landing aircraft

Abstract

The configuration and control system of a vertical take-off and landing (VTOL) aircraft includes multiple turbojet or turbofan engines that provide vertical elevation and control for hovering and low ground speeds. For higher speed flights, a separate cruising propulsion system generates thrust. This lift during higher speed flights is provided by one or more wings. During the transition between low-speed and high-speed flights, both systems provide forward thrust, control, and lift.

Description

Technical Field

[0001] (Reference to Related Applications) This application claims priority to U.S. Provisional Patent Application No. 63 / 508,987, filed on June 19, 2023, the entire content of which is incorporated herein by reference.

[0002] (Technical Field) The present disclosure relates to vertical take-off and landing (VTOL) aircraft, and more particularly to VTOL aircraft having significant range and endurance requirements.

Summary of the Invention

[0003] In a first independent aspect, which may be combined with any other aspect, the aircraft includes a fuselage, wings, a first engine, and a plurality of second engines. The wings are coupled to the fuselage and include a first wing and a second wing. The first wing includes a first inner wing and a first outer wing connected by a first pod, and the second wing includes a second inner wing and a second outer wing connected by a second pod. The first engine is coupled to the fuselage and provides thrust axially. The plurality of second engines are operatively coupled to the fuselage such that each second engine of the plurality of second engines provides thrust in a direction perpendicular to the axial direction and is rotatable about the axial direction. Each second engine of the plurality of second engines is coupled to one of the first pod or the second pod. Further, each second engine of the plurality of second engines is rotatable about the axial direction such that each second engine of the plurality of second engines is rotatable within the outer profile of one of the first pod or the second pod.

[0004] In another embodiment, which may be combined with any other embodiment, the aircraft includes a fuselage, a first engine coupled to the fuselage to provide thrust in the axial direction, and a plurality of second engines, each of which is operationally coupled to the fuselage to provide thrust in a direction perpendicular to the axial direction and is rotatable in the axial direction. [Brief explanation of the drawing]

[0005] [Figure 1] A front perspective view of the first exemplary aircraft is shown.

[0006] [Figure 2] Figure 1 shows a top view of an exemplary aircraft.

[0007] [Figure 3] A front perspective view of a second exemplary aircraft is shown.

[0008] [Figure 4] Figure 3 shows a top view of an exemplary aircraft.

[0009] [Figure 5] This shows a top-view perspective of the rear second engine of an aircraft with the second engine in its stowed position.

[0010] [Figure 6] Figure 5 shows a top-view perspective of the rear second engine of the aircraft in which the second engine is in the operating position.

[0011] [Figure 7] This shows a top-view perspective of the forward second engine of an aircraft with the second engine in its stowed position.

[0012] [Figure 8] Figure 7 shows a bottom perspective view of the forward second engine of the aircraft, with the second engine in its stowed position.

[0013] [Figure 9]This shows a top-view perspective of the forward second engine of an aircraft with the second engine in the operating position.

[0014] [Figure 10] Figure 7 shows a bottom perspective view of the forward second engine of the aircraft in which the second engine is in the operating position. [Modes for carrying out the invention]

[0015] Preferred embodiments of the present disclosure are described herein with reference to the accompanying drawings. In the following description, well-known features or structures are not described in detail because they may be obscured by unnecessary details. As used herein, the term “exemplary” means to serve as a non-limiting example, instance, or illustration. As used herein, the terms “eg” and “for example” evoke a list of one or more non-limiting examples, instances, or illustrations.

[0016] Before any embodiment of the present invention is described in detail, it should be understood that the present invention is not limited in its application to the detailed configuration and arrangement of components described in the following description or shown in the following drawings. Other embodiments of the present invention are possible and can be carried out or implemented in various ways. It should also be understood that the usage and terminology used herein are for illustrative purposes only and should not be considered as limitations.

[0017] Figures 1 and 2 show different diagrams of a vertical take-off and landing (VTOL) aircraft, i.e., aircraft 100, more specifically, aircraft 100 having substantial range and endurance requirements. Aircraft 100 achieves sustained, fuel-efficient flight at relatively higher speeds via wings 105 and a first engine 110. In some embodiments, wings 105 include canards. Here, the term “higher-speed flight” means flight at an airspeed well above the stall speed of aircraft 100 (i.e., the speed at which the weight of the aircraft is substantially offset by the lift generated by wings 105), in which case lift and control can be safely maintained without supplementation from other engines such as a second engine 115. The term “low-speed flight” is used to mean flight at an airspeed at which the wings 105 and other surfaces of aircraft 100 do not generate substantial lift.

[0018] The first engine 110 is a propeller operated by at least one selected from the group consisting of an internal combustion engine, a jet engine, and an electric motor, and operates the aircraft 100 in cruising conditions. As shown in Figure 1, the first engine 110 is a pusher propeller. The aircraft 100 achieves hovering and vertical lift and control at low airspeeds via a plurality of second engines, i.e., second engines 115. The second engines 115 are turbojet engines, turbofan engines, or ducted fan engines (collectively, "jet" engines).

[0019] In some examples, VTOL aircraft similar to aircraft 100 utilize multiple rotors for hovering and low-speed lift and descent, and a separate propulsion system of one or more motors solely for generating thrust during cruising. The lift rotor is active only during vertical takeoff and landing, and the cruising propulsion system is active only during the higher-speed cruising portion of the flight. The lift rotor is typically driven by large electric motors and large banks of batteries. This makes the lift system heavy, and the lift rotor is cumbersome to retract for cruising flight. In practice, the lift rotor is often left exposed during cruising flight, adding considerable drag, which reduces range, endurance, top speed, and climb performance. Large battery banks pose logistical and safety problems in operation. In other examples similar to aircraft 100, VTOL aircraft may utilize one or more turbojet or turbofan engines for both vertical lift at low speeds and cruising thrust at higher speeds. These turbojet or turbofan engines are noisy and inefficient in cruising flight, significantly limiting the range and endurance of such aircraft. Smaller turbojet engines are particularly inefficient, further limiting the range and endurance achievable in smaller unmanned aerial vehicles that utilize jet propulsion.

[0020] The aircraft 100 shown in FIG. 1 addresses the drawbacks of these other proposed VTOL aircraft. The aircraft 100 includes a wing 105 coupled to a fuselage 120. The fuselage 120 has a first engine 110 coupled thereto. The first engine 110 provides thrust in an axial direction 145 that is aligned with the longitudinal axis of the generally cylindrical fuselage 120. In an example where the first engine includes a propeller 112 as shown in FIG. 1, the axial direction is collinear with the axis of rotation of the propeller. The axial direction 145 includes a forward direction 150A and an aft direction 150B that is opposite the forward direction 150A. Since the first engine 110 is a pusher propeller, the first engine is disposed in the aft direction 150B of the fuselage 120. Propulsion of the first engine 110 may be provided from an internal combustion engine, an electric motor, a turboprop engine, or a combustion / electric hybrid. Embodiments that utilize a combustion engine that can operate on the same fuel as a jet engine (e.g., kerosene-based fuel, diesel fuel, and hydrogen) are particularly beneficial because the use of a common fuel reduces logistics requirements and increases mission flexibility.

[0021] In the embodiment shown in FIG. 1, the camera 155 is disposed in the forward direction 150A of the fuselage 120, i.e., at the nose of the aircraft 100. The pusher propeller layout of the first engine 110 enables data and sensing equipment to be disposed in the forward 150A portion of the fuselage 120. The fuselage also includes other components such as a controller 160 configured to control the operation of the first engine 110, the second engine 115, and the control surfaces 140 on the wings 105, such as flaps, elevons, and ailerons, and the control surfaces on the vertical rear 175A and 175B. In some examples of the aircraft 100, the controller 160 receives signals wirelessly and operates the aircraft so that the aircraft 100 can be controlled by a user during flight from a location remote from the aircraft 100. In a preferred embodiment, the controller 160 uses feedback from a system of sensors (e.g., accelerometers, gyroscopes, GPS, and engine RPM) to perform closed-loop control of the position, attitude, and speed of the aircraft 100 in the performance of higher-level commands from a remote user or a mission autonomous system. In some examples, the second engine 115 is removable so that the aircraft 100 can operate as a conventional takeoff and landing aircraft.

[0022] The wings 105 include a first wing 105A and a second wing 105B. The first wing 105A includes a first inner wing 125A and a first outer wing 130A connected by a first pod 135A. The second wing 105B includes a second inner wing 125B and a second outer wing 130B connected by a second pod 135B. In the embodiment shown in FIG. 1, the first and second inner wings 125A, 125B are disposed in the forward direction 150A along the axial direction 145 with respect to the first and second outer wings 130A, 130B.

[0023] The first pod 135A is generally cylindrical and includes an external profile 165A. The second pod 135B is also generally cylindrical and includes an external profile 165B. In the embodiment shown in Figure 1, each of the first and second pods 135A, 135B includes two of the second engines 115. Thus, the second engines 115 are operably coupled to the fuselage 120 but not directly coupled to the fuselage 120. In other embodiments, only two of the second engines 115 are provided, i.e., one is provided in each of the first and second pods 135A, 135B. In yet another embodiment, more of the second engines 115 are provided. Regardless of the number of second engines 115 provided, the second engines 115 are spaced apart such that the combined thrust from the second engines 115 is located at or near the center of mass 170 of the aircraft 100.

[0024] In some examples, each of the first and second pods 135A and 135B includes their respective vertical stabilizers 175A and 175B. Both the first and second vertical stabilizers 175A and 175B include a control surface 140. In the embodiment shown in Figure 1, the first vertical stabilizer 175A is located between the two second engines 115 on the first pod 135A. Similarly, the second vertical stabilizer 175B is located between the second engines 115 located on the second pod 135B. In other examples, the vertical stabilizers 175A and 175B are not included in the aircraft 100.

[0025] The second engines 115 are operationally coupled to the fuselage such that each of them provides thrust in a direction substantially perpendicular to the axial direction. The second engines are in this position when the aircraft 100 is taking off or landing. During takeoff and landing of the aircraft 100, the wings 105 are generally in a stalled state and do not generate lift, or only accidental lift. Therefore, during takeoff and landing, lift for the aircraft 100 is provided solely by the second engines 115.

[0026] As aircraft 100 transitions from vertical flight during takeoff to horizontal flight (i.e., flight moving axially 145 so that the wings 105 generate lift), the second engine 115 rotates axially 145. For engines with a centerline (i.e., engines with a fan rotation axis, such as turbojet engines, turbofan engines, or ducted fan engines), rotation axially 145 means rotating the centerline of the second engine 115 from a position perpendicular to axial 145 toward axial 145. This is best illustrated by comparing Figure 5-10, which shows examples of the second engine 115 in its operational position (i.e., the position that provides thrust during takeoff, vertical flight, and / or landing) and its stowed position (i.e., the position in which the second engine 115 is rotated so that it is roughly aligned with axial 145).

[0027] Taking Figures 5 and 6 as examples, Figure 5 shows the second engine 115 in the stowed position, while Figure 6 shows the second engine 115 in the operational position. When the second engine 115 rotates about the rotation axis 183 toward the axial direction 145, each of the second engines 115 is retracted into the cavity 185. As the second engine 115 rotates toward the axial direction 145, the second engines provide thrust toward the axial direction 145 until the second engine 115 is retracted. This provides some airspeed toward the axial direction 145 until the first engine 110 takes over to provide primary power to the aircraft. When the second engine 115 is retracted, the second engines are fully retracted into the external profiles 165A, 165B of the first pod 135A or the second pod 135B to which the second engine 115 is mounted. Rotating the second engine 115 within external profiles 165A and 165B significantly reduces the drag of the aircraft in flight in the axial direction 145, resulting in a significantly more efficient aircraft 100. Ideally, the second engine 115 would be tightly fitted within the cavity 185 to reduce drag as much as possible. However, due to the tight fit within the cavity 185, when the second engine 115 is retracted, the power of the second engine is shut off. Otherwise, the first pod 135A and the second pod 135B would need to include complex ducts to supply air to the second engine 115 and remove exhaust from the second engine 115. Furthermore, this tight fit eliminates the use of doors to seal the cavity 185, because any additional drag reduction provided by doors is already reduced by the tight fit, and the doors would only provide additional complexity without significant performance gains.

[0028] Figures 5 and 6 show the second engine 115 at the aft 150B end of the first pod 135A or the second pod 135B, whereas Figures 7 to 10 show the same phenomenon with respect to the forward second engine 115 in the first pod 135A or the second pod 135B.

[0029] The second engines 115 are rotated around a rotation axis 183 and direct thrust along the axial direction 145 (for example, at an angle between + / 50 degrees perpendicular to the axial direction 145, or in some embodiments at an angle between +50 degrees and -30 degrees perpendicular to the axial direction 145), but other fine-tuning must be done to the thrust direction and thrust level of each engine so that the aircraft 100 can safely take off, land, transition to higher speed flight, and hover when required. For example, the second engines 115 may need to compensate for wind moving in a direction perpendicular to the axial direction 145. Each of the second engines 115 includes an inlet 190 and an exhaust nozzle 195. Air is drawn into the inlet 190, combustion occurs, and exhaust is directed from the exhaust nozzle 195. To fine-tune the direction of thrust from each of the second engines 115, the exhaust nozzles 195 are adjustable and can be supported by a gimbal. Furthermore, the second engine 115 is individually adjustable (for example, in the gimbal position and around its respective axis of rotation 183) so that it can provide thrust together in a desired direction, while compensating for other external factors such as wind, enabling the aircraft 100 to perform maneuvers such as takeoff, landing, and hovering.

[0030] Figures 3 and 4 show embodiments of aircraft 100 different from those shown in Figures 1 and 2. For example, the first engine 110 is in a tractor-propeller configuration. The fuselage is elongated in the rearward direction 150B and includes a horizontal stabilizer 200 and a vertical stabilizer 205 at the rearmost end. The horizontal stabilizer 200 and vertical stabilizer 205 include control surfaces 140 such as rudder, ailerons, and flaps. Thus, the first and second pods 135A, 135B do not include vertical stabilizers 175A, 175B, as shown in Figures 1 and 2. Other examples of aircraft 100 use an upward-oriented vertical tail array, or various other tail configurations including V-tails, A-tails, and T-tails.

[0031] Furthermore, the wings 105 of the aircraft 100 shown in Figures 3 and 4 are substantially uniform across the aircraft 100 with respect to the axial direction 145. The wings 105 extend substantially perpendicular to the axial direction 145 on both sides of the fuselage 120. The first and second pods 135A and 135B are attached to the wings 105 on the opposite side of the fuselage 120 or suspended from the wings 105. Similar to the aircraft shown in Figures 1 and 2, the two second engines 115 are attached to the first pod 135A in forward position 150A and aft position 150B, and the two second engines 115 are attached to the second pod 135B in forward position 150A and aft position 150B. The second engines 115 function in the same way as described with respect to the second engines 115 shown in Figures 1 and 2.

[0032] Overall, the first engine 110 and the second engine 115 provide a dynamic flight envelope for the aircraft 100. The aircraft 100 uses the first and second engines 110 and 115 for lift, thrust, position control, and attitude control during vertical takeoff, vertical landing, and low-speed flight. Attitude and position control at low speeds is achieved by varying the thrust level and direction of the second engine 115, as shown in Figures 1 to 4. At least a portion of the second engine 115 is offset from the center of mass 170 so that varying the magnitude and direction or line of thrust generates sufficient torque in the aircraft 100 for attitude control. The thrust of the second engine 115 may be directed forward 150A and aft 150B to help accelerate and decelerate the aircraft along the axial direction 145 through the transition between low-speed and higher-speed flight. Roll, pitch, and vertical velocity are controlled by varying the thrust of the second engine 115. Thrust changes in the second engine 115 can be generated by changing the throttle (fuel flow rate), by changing the geometric shape of the jet outlet nozzle, and by changing the blockage of the jet exhaust flow.

[0033] During the transition between low-speed and high-speed flight, lift, attitude control, speed control, and position control are provided by a combination of low-speed and high-speed controls. This mixture of controls may vary depending on airspeed and other factors such as aircraft weight, altitude, and system operation adjustments. In some examples, an aircraft may have eight second engines operating in pairs, which may provide redundancy and improved control bandwidth.

[0034] In some examples, aircraft 100 is equipped with landing gear that enables jet-assisted rolling takeoff. This “short takeoff” capability may provide increased lift capacity. This short takeoff capability may substitute for or in addition to vertical takeoff capability.

[0035] In any configuration, the fuselage 120, pods 135A and 135B, wings 105, and vertical stabilizers 175A and 175B may house sensors, cargo, flight control equipment, landing gear, fuel, batteries, antennas, and other aircraft systems, as well as payload components best suited to the specific vehicle deployment and mission.

Claims

1. Torso and, The wing is attached to the fuselage and includes a first wing and a second wing, the first wing includes a first inner wing and a first outer wing connected by a first pod, and the second wing includes a second inner wing and a second outer wing connected by a second pod, A first engine, coupled to the fuselage and configured to provide thrust in the axial direction, The plurality of second engines include each second engine being operationally coupled to the fuselage so as to provide thrust in a direction perpendicular to the axial direction and to rotate in the axial direction, and each second engine of the plurality of second engines being coupled to one of the first pods or the second pods, Each of the plurality of second engines is configured to rotate within the external profile of one of the first or second pods. aircraft.

2. The aircraft according to claim 1, wherein each of the plurality of second engines is arranged at intervals such that the combined thrust from the plurality of second engines is located at the center of mass of the aircraft.

3. The first vertical stabilizer is positioned on the first pod between two of the plurality of second engines that are mounted on the first pod. The second vertical stabilizer is positioned in the second pod between two of the multiple second engines that are mounted in the second pod. The aircraft according to claim 2.

4. The aircraft according to claim 1, wherein each of the plurality of second engines is configured to provide thrust that accelerates the aircraft in the axial direction as each of the plurality of second engines is rotated in the axial direction.

5. The first engine includes a propeller, The axial direction is on the same line as the rotation axis of the propeller. The aircraft according to claim 1.

6. The aircraft according to claim 1, wherein each of the plurality of second engines is configured to stop while rotating in the axial direction.

7. The second inner wing is offset in the axial direction from the second outer wing, The first inner wing is offset in the axial direction from the first outer wing. The aircraft according to claim 1.

8. The aircraft according to claim 1, wherein the plurality of second engines are configured to provide thrust to the aircraft when the wings are in a retracted position.

9. The aircraft according to claim 8, wherein the aircraft is configured to take off vertically or conventionally.

10. Torso and, A first engine, coupled to the fuselage and configured to provide thrust in the axial direction, The plurality of second engines include, each of which is operably coupled to the fuselage so as to provide thrust in a direction perpendicular to the axial direction and to rotate in the axial direction, aircraft.

11. The aircraft includes a wing having a first wing and a second wing, The first wing includes a first inner wing and a first outer wing connected by a first pod, The second wing includes a second inner wing and a second outer wing connected by a second pod, The aircraft according to claim 10.

12. Two of the plurality of second engines are attached to the first pod, and two of the plurality of second engines are attached to the second pod. Each of the two second engines of the plurality of second engines mounted on the first pod is configured to rotate within the external profile of the first pod, and each of the two second engines of the plurality of second engines mounted on the second pod is configured to rotate within the external profile of the second pod. The aircraft according to claim 11.

13. The aircraft according to claim 12, wherein each of the plurality of second engines is spaced apart such that the combined thrust from the plurality of second engines is located at the center of mass of the aircraft.

14. The aircraft according to claim 13, wherein the plurality of second engines are turbofan engines.

15. The aircraft according to claim 13, wherein the plurality of second engines are turbojet engines.

16. The aircraft according to claim 14, wherein each of the plurality of second engines includes an exhaust nozzle supported by a gimbal, and each of the gimbal-supported exhaust nozzles is configured to be individually controllable.

17. The aircraft according to claim 10, wherein the first engine includes a propeller operated by at least one selected from the group consisting of an internal combustion engine, a jet engine, and an electric motor.

18. The first engine is a pusher propeller, including a propeller. The axial direction is on the same line as the rotation axis of the propeller. The aircraft according to claim 17.

19. The aircraft according to claim 12, wherein the first pod includes a first vertical stabilizer, and the second pod includes a second vertical stabilizer.

20. The aircraft according to claim 19, wherein the first vertical stabilizer, the second vertical stabilizer, and the wings include control surfaces.

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