Vertical short-distance take-off and landing lift boosting system

Abstract

A propulsion system for a vehicle includes: at least one generator; at least one supercapacitor coupled to the at least one generator; at least one battery coupled to the at least one generator; at least one compressor coupled to the at least one generator, the at least one supercapacitor, and the at least one battery; and at least one propulsion element coupled to the compressor.

Description

[0001] Copyright Notice

[0002] This invention is protected by U.S. and / or international copyright laws. ©2023 Jetoptera, Inc. All rights reserved. Portions of the patent document disclosed herein contain copyrighted material. The copyright owner does not object to anyone faxing a reproduction of the patent document or patent disclosure, provided it appears in the patent file or records of the Patent and / or Trademark Office, but reserves all copyrights otherwise.

[0003] Priority Claim

[0004] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 427,043, filed on November 21, 2022, the content of which is incorporated herein by reference in its entirety as if fully set forth herein. Background Art

[0005] Existing VTOL and STOL thrusters face significant challenges in selecting the appropriate size or power of the propulsion system due to the significant difference between the power required for takeoff and the power required for cruise. Some systems involve rotors or tiltrotors or ducted fans, vectoring jet engines, or combinations thereof (referred to as compound helicopters), but these systems have a low lift-to-drag ratio, resulting in limited endurance and restricted speed. Aircraft such as the Hammer vertical takeoff and landing aircraft perform well in VTOL, but due to the large size of their propulsion systems, they cannot achieve the expected cruise speed. Therefore, the challenge for any VTOL aircraft is the selection of the thruster, which typically ends up accounting for a large portion of the total aircraft weight, thereby limiting the payload as well as the range and endurance. When the size of a large turbine system is suitable for VTOL (vertical takeoff and landing), during cruise, its operating point deviates from the VTOL operating point, resulting in the turbine being efficient only during the takeoff phase and significantly less efficient during cruise.

[0006] Current military or civilian V / STOL aircraft propulsion systems rely on large tilting rotors, such as the V-22 Osprey or the Agusta AW609, or on large fixed ducted fans, such as the F-35 fighter jet. The challenge with the latter is that, during non-vertical flight segments, the fixed ducted fan becomes dead weight for 99% of the mission time. When fuel runs out during the mission and the aircraft is lighter, and can use on-board power to land vertically, since the weight replaced by the vertical takeoff fan limits the aircraft to vertical landing only, the F35 is now known as STOVL rather than VTO. This also limits its payload capacity, especially in smaller, non-integrated, or unmanned applications, where it is particularly complex and costly. The challenge with the V22 rotors is that they have a large footprint and must tilt with high precision, but they still limit the maximum speed due to the rotor tip speed limitation. The development history of the V22 also shows that it has serious flaws, resulting in a large number of casualties. There is a need for a high-speed VTOL propulsion system that can propel the aircraft to fly at the high speeds or with high endurance required for intelligence, surveillance, and reconnaissance. Most eVTOL aircraft use tilting multi-propellers, which are highly efficient, but they rely on very heavy batteries with an energy density many times lower than jet fuel. Among the hundreds of proposed eVTOL platforms, many use multiple distributed fixed propellers for vertical takeoff and a single propulsive propeller for horizontal flight, and their speeds are also severely limited. Therefore, there is clearly a need for a novel propulsion method to optimize operation under cruise conditions and be lighter than battery-powered vehicles or oversized VTOL turbines.

[0007] While engineers are implementing complex and costly technologies to maximize the hover efficiency of propellers, current small propellers are inefficient and expensive. The speeds of cargo drones and urban air mobility flying cars (air taxis) are limited to relatively low values, and propellers are noisy and inefficient at this size.

[0008] Most hybrid V / STOL aircraft are likely to use a hybrid system called a range extender system, while all-electric aircraft are typically very severely limited in range and endurance. Again, this is because these aircraft require a large number of batteries, so it is thought that a hybrid system involving a generator could double the range of aircraft such as eVTOLs. However, the fact is that even if an on-board generator can generate electricity to drive the motors of rotary fans or propellers, its impact on the aircraft is still more harmful than a pure fuel propulsion system due to the need to add additional components to the original system. Generators usually need to be equipped with inverters, regulators, cooling devices, large cables, power transmission systems and electronics, and may even require batteries. As one expert put it, this results in the entire hybrid system being "three times more expensive, twice as heavy, and 10% less efficient overall". This is because by adding additional components, the efficiency of these components themselves is far from 100%, the thermal efficiency of the power plant will be significantly reduced, the propellers will become heavier, less efficient, and more costly to maintain and operate, not to mention that it replaces useful payloads with components not present in traditional systems.

[0009] In addition, the power boost required for V / STOL aircraft usually only accounts for a very small part of the entire mission, most likely at the start and end, which makes it more difficult to select the correct propulsion and energy storage combination. For example, a VTOL aircraft only needs to hover or take off and land vertically for 1-2 minutes, while it needs to fly continuously for several hours in the cruise state (or wing-borne).

[0010] Therefore, it makes sense to create an architecture that allows a V / STOL aircraft to use a generator to operate efficiently during cruise, which operates at its highest efficiency point, but benefits from some enhanced power for lift generation during the vertical phase of the mission, without adding bulky and low-energy-density systems such as batteries, motors, and auxiliary systems. Such a system will actually significantly optimize the operation of any V / STOL aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 is a schematic diagram of a hybrid VTOL system according to an embodiment;

[0012] Figure 2 shows the operation during vertical takeoff according to an embodiment;

[0013] Figure 3 shows the operation during transition to wing-borne according to an embodiment;

[0014] Figure 4 shows the operation during wing-borne according to an embodiment;

[0015] Figure 5Illustrates the operation of bypassing battery usage during wing loading while charging the battery according to one embodiment;

[0016] Figure 6 Illustrates an alternative wing loading operation using an electric ducted fan according to one embodiment; and

[0017] Figure 7 Illustrates an alternative wing loading operation using an electric-driven propeller according to one embodiment. Detailed Description

[0018] This application aims to describe one or more embodiments of the present invention. It should be understood that the use of absolute terms such as "must", "will", etc. and specific quantities should be interpreted as applicable to one or more such embodiments, but not necessarily including all such embodiments. Thus, embodiments of the present invention may omit or include modifications to one or more features or functions described in the context of these absolute terms. Additionally, the headings in this application are for reference only and should not in any way affect the meaning or interpretation of any embodiment of the present invention.

[0019] Embodiments of the present invention disclosed in this application relate to enhanced propulsion systems, which specifically operate with an electric motor that powers an air compressor, a fan, or a propeller. Instead of designing the propulsion system of the aircraft 100 to generate a maximum force that is at least 20% greater than the weight of the vertical takeoff aircraft system, which would lead to an increase in the weight of the propeller under cruise conditions, it involves using a supercapacitor or supercapacitors that can deliver a large amount of electrical power in a short period of time, enabling sufficient power to be provided to the electrical components on the aircraft to lift the aircraft off the ground or for vertical landing. A supercapacitor (SC), also known as an ultracapacitor, is a high-capacity capacitor with a much higher capacitance value than other capacitors but a lower voltage limit, filling the gap between electrolytic capacitors and rechargeable batteries. Different from ordinary capacitors, a supercapacitor does not use a traditional solid dielectric, but instead uses a double-layer capacitance on one electrode and an electrochemical cell electrode on the other electrode.

[0020] One or more embodiments include a novel hybrid propulsion method that can avoid the drawbacks of propellers. The thruster is designed based on the principle of thrust augmentation using special ejectors and upper surface blowing lift augmentation. Such ejectors can include those disclosed in U.S. Provisional Patent Application No. 62 / 213,465 filed on September 2, 2015, and U.S. Patent Application No. 15 / 256,178 filed on September 2, 2016, each of which is incorporated herein by reference as if fully set forth herein. The air supply may come from, for example, an electric turbo compressor, an electric turbo fan, or any electric air compressor that can produce a sufficient air supply with a pressure ratio of at least 1.5:1 and is powered by at least two power sources: a generator and a series of supercapacitors.

[0021] Figure 1 A VTOL configuration of an embodiment of the present invention is shown, in which compressed air is generated by an air compressor 101. The compressor 101 can be an electric turbo fan with a bypass air flow function or any other type of fan and compressor that can generate a large amount of air flow with a pressure ratio of at least 1.5 times the ambient pressure. The air compressed by the compressor 101 can be delivered to the wing-mounted ejector 108 and / or used for other purposes, including being directed to the intake of an auxiliary nozzle or for cooling, thrust augmentation, cabin pressurization, or other purposes. In different embodiments, the wing-mounted ejector 108 can be positioned or embedded in an aerodynamic surface such as a wing 104. Similar to a typical turbocharger compressor, the compressor 101 preferably has a pressure ratio of 2.5 or higher during peak operation. A valve may be provided on the compressor exhaust volute to direct the compressed air to an auxiliary compressor or outside the gas generator as needed.

[0022] Part of the power supplied by the electric compressor 101 is provided by a generator 102 designed for the cruise conditions of the aircraft. For example, if the cruise demand is 1 / 2 of the power required for takeoff, then the size of the generator 102 is precisely corresponding to that rated power, so as to generate the best power at the best operating point during the entire mission.

[0023] The remaining power required for takeoff, hovering, or vertical landing or whenever the compressor 101 is needed to enhance the propulsion force is provided by a series of advanced capacitors or supercapacitors 110, which are much stronger than batteries in generating electricity at high current and high voltage in a short time. The advantages of these supercapacitors 110 also lie in that they can be quickly charged from the generator 102 within a few minutes during flight. By correctly sizing the system, the aircraft 100 can operate extremely efficiently, can take off and land vertically quickly, and can even hover for a few minutes without carrying a large battery, because a large battery cannot provide the high power required for these flight instances and there is no risk of thermal runaway or serious thermal management problems understood by those familiar with the matter.

[0024] In one embodiment, the aircraft 100 is a small unmanned system weighing 350 lb, which carries a payload of, for example, 60 lb and 110 lb of fuel. The generator 102 is a regenerative gas turbine or a very efficient piston engine (e.g., continuously generating 15 kW of electricity at high efficiency) and weighs 70 lb. Three supercapacitors 110, each weighing no more than 45 lb, can jointly provide a total of 90 kW of electricity for up to 2 minutes, supplying the required balanced power to all the motors driving the compressors, fans, or propellers dedicated to the vertical takeoff and landing phases. This, in turn, provides sufficient thrust for the aircraft to take off or land vertically. In the case where all the thrust is used to overcome drag, the generator 102 can remain "on" continuously to provide the 15 kW of electricity necessary for forward flight (or wingborne flight), while the wings 104 are mainly responsible for generating lift. In addition, the generator 102 is also responsible for supplying power to various on-board functions, including components for navigation, communication, aircraft control, servo systems, and payloads. This 350-lb aircraft has large wings with a lift-to-drag ratio of 20 at a forward speed of only 30 knots, and the drag generated at this speed is only 350 lb / 20 = 17.5 lb force; this can be overcome by using an electric compressor that produces a jet of 18 lb force at a moderate pressure ratio of 1.1 and supplies it to an ejector with a boost ratio of 2.5 and consumes only 5 kW. As the speed increases, with a lift-to-drag ratio of, for example, 25, the power requirement will be minimized, and the turbogenerator can provide a propulsion device for the system to extend the range and endurance, a charging device for the supercapacitors, power for the aircraft's control, communication, navigation, etc., and power for the payload, while burning only a very small amount of fuel, for example, with a total output power of only 10 kW - if it is an efficient regenerative turbogenerator, it is 0.6 lb / HP / h or 0.365 kg / kW / h. Since the aircraft gradually loses weight during fuel consumption, the aircraft can fly in wingborne flight mode for a relatively long time. For example, conservatively speaking, 100 lb of fuel can support flight for about 12.4 hours (calculated as 100 lb / (0.6 lb / HP / h × 13.4 HP)). If it is assumed that the true speed is 100 knots and 100 lb of fuel on the aircraft is consumed, when the lift-to-drag ratio is 25, using the Breguet equation to calculate the range, the endurance will exceed 15 hours. The generator outputs a power equivalent to 13.4 HP (i.e., 10 kW) during wingborne flight, which is sufficient to support a small aircraft for an important communication mission of nearly 16 hours and a distance of 1900 miles, demonstrating extraordinary endurance.

[0025] It should be noted that if a battery is used instead of the supercapacitor 110, with an energy density of 150 Wh / kg and required to supply 45 kW of power within a few minutes, the weight of just the battery alone added to the vehicle would exceed 200 lb, which is heavier than the generator 102 itself, and is not suitable for a 350 lb system where the combined weight of the generator and battery accounts for 77% of the total weight of the aircraft. Since the chemical reactions inside the battery would accelerate to a certain extent, causing the battery to become useless or even explode, it is impossible to rapidly discharge the battery. Only a battery with a large capacity can achieve such a significant increase in takeoff power consumption in a short time, but this would correspondingly increase the weight of the vehicle and might not even fundamentally solve the problem. Compared with supercapacitors, the charging time of the battery is also two orders of magnitude longer. This is why a hybrid system using capacitors and supercapacitors can uniquely enable V / STOL and other applications.

[0026] In another embodiment, a 360° rotatable VTOL ejector 107 is used for VTOL, and air is supplied by an electric compressor 101 powered by the supercapacitor 110 for several minutes. When the aircraft 100 is in wingborne flight, the supercapacitor 110 is no longer powered, and the turbogenerator 102 becomes the sole power source, providing the required power for a single forward flight propeller (such as a propeller, fan, or ejector or a combination thereof).

[0027] In another example, a compressor is used, such as a compressor typically used in a turbocharger or an electric compressor operating at a maximum pressure ratio of 2.0:1 and an isentropic efficiency of over 85%, to produce a power air flow of 1 lb / s; in this case, the input mechanical or electrical power required to drive the air compressor is 38 HP (horsepower) or approximately 29 kW; this power air flow is supplied to a fluid propulsion system deployed on the wing or around the fuselage, actually a thruster - ejector, which, when deployed at the correct angle and passed through an upper surface blowing configuration with a flap located above the deployed flap, produces twice the lift at speeds as low as 10 knots compared to the case of using a clean wing without a thruster enhancer being active or present at the same upwind speed (10 knots). This would allow the aircraft to perform ultra - short takeoff and landing (SSTOL) or ultimately vertical takeoff into the headwind, such as vertical takeoff on a headwind - facing ship deck. For example, under 10 - knot headwind conditions, if the flaps are deployed, for an input power of 38 HP, the typical lift obtained by the blown wing can be approximately 200 lbf, which results in a ratio of 5.26 lbf / HP, as described by Maiselet et al. - NASA SP - 2000 - 4517, "The History of the XV - 15 Tilt Rotor Research Aircraft:

[0028] As explained in “From Concept to Flight” (Bibliographic Data) https: / / ntrs.nasa.gov / search.jsp?R=20000027499 (PDF) http: / / hisiory.nasa.gov / monograph17.pdf, this is a common value for the hover efficiency of tiltrotors such as the V22 Osprey or helicopters.

[0029] Therefore, in addition to being equipped with an electric generator optimized for cruise conditions, which also serves as a charging device for supercapacitors during flight, the aircraft is also capable of generating several times the vertical thrust, such as 200 lb of force, in a low-speed headwind using multiple 38HP electric compressors (which can be powered by advanced capacitors or supercapacitors). Thus, a 380HP load can be directly directed to the electric compressors distributed on the aircraft and powered by a combination of an auxiliary power unit and a lightweight supercapacitor, used in conjunction with fluid propeller boosters and flaps on the blowing wings, to generate a vertical force of 2000 lbf by employing a power airflow of 10 lb / s at an ambient pressure ratio of 1.8 (where the APU is designed to be only 120HP (90kW) for example and weighs less than 150 lb), along with an additional 260HP (200kW) from a supercapacitor weighing 100 lb, which is sufficient for vertical takeoff or landing in a short period of time. For an on-board permanent battery performing the same task, 500 lb of battery would be required to provide 200kW of power and its duration would be longer.

[0030] The advantage of this is that once the aircraft is airborne and has achieved forward speed, the supercapacitor is immediately charged.

[0031] As Figure 1The system shown has a generator 102 that supplies power to a plurality of components (motor, payload, navigation, communication, control, and a supercapacitor 110 sized for a VTOL aircraft). The turbogenerator 102 can have a maximum output power of up to 15 kW when operating at full load, and with the priority use of regenerative technology, its efficiency can be as high as 30%. The turbogenerator 102 can also be optionally a piston engine generator or other generators designed to minimize weight and maximize efficiency, preferably driven by jet fuel, diesel, or other preferred fuels (including hydrogen). The generator 102 can be electrically connected to a series of electric compressors 101, a battery 103 for buffering, and a series of supercapacitors 110. The battery 103 can also be connected to other components, such as a servo or wing-mounted thrusters, such as an electric ducted fan 105, a motor driving a propeller 106, another compressor 101 that delivers air to a thruster injector 108, or an electric compressor 101 that can be used for a dual role, delivering air to the injector or simply diffusing compressed air in the form of a jet into the surrounding environment. The injector 108 can also be used in combination with the wing 104, an augmented wing during takeoff, or the injector 108 in general. During takeoff, the generator generates 15 kW of power, while the capacitors provide an additional 90 kW of power within seconds to minutes. After the aircraft transitions to forward flight (also known as wing-borne flight), all power from the supercapacitors 110 is cut off, and the turbogenerator 102 supplies power only as needed for thrust to power one of the wing-mounted thruster motors to propel the aircraft. The propeller 106 driven by the motor consumes the least amount of energy, thus having a high endurance, but is very noisy and can be easily detected from a distance. The electric ducted fan 105 is the least efficient, but is quieter during long-distance operation, producing only high-frequency noise and can be quickly absorbed from a distance. If the compressor embedded in the aircraft is used in combination with a muffler and combined with an FPS-type injector 108, lower noise can be generated, making the thruster efficient and quiet, without noise frequency peaks, and more like wind, with only broadband noise. One, several, or all of these options can be employed on the vehicle as needed, and the supercapacitors can be charged within seconds.

[0032] In another embodiment, the hybrid propulsion system is used for short take-off and landing (STOL) aircraft, much like rocket-assisted take-off (RATO) or jet-assisted take-off (JATO) which are used for 10 - 30 seconds each time. The difference is that the supercapacitor can be used for the same duration but is cleaner, can enhance lift, then be recharged on board during flight and can be reused thousands of times. The rockets used for JATO and RATO can only be used once. In this embodiment, the compressor is embedded in the wing and close to the ejector (such as an FPS ejector), working in concert with the wing to generate boost force, blowing air through the FPS and the upper surface of the wing, enabling the aircraft to achieve a faster and cleaner lift-off. Since the supercapacitor can be repeatedly charged thousands of times within seconds, the lift coefficient can be significantly increased to a double-digit level, and the process is repeated until the aircraft climbs to a high altitude.

[0033] Figure 2 Illustrated is the operation of an aircraft 100 during vertical take-off according to an embodiment. In this configuration, the compressor 101 obtains power from at least one of the generator 102, the capacitor 110, or the battery 103. The powered compressor 101 in turn supplies compressed air to the VTOL ejector 107, and the configuration and orientation of the VTOL ejector 107 can provide thrust and lift to the aircraft 100, thus facilitating vertical take-off.

[0034] Figure 3 Illustrated is the operation of an aircraft 100 during the transition to a wing-borne configuration according to an embodiment. In this configuration, the supercapacitor 110 no longer provides power, and only the turbogenerator 102 and / or the battery 103 power one or more forward flight thrusters, which include the propeller 106, the fan 105, the wing-borne ejector 108, or any combination thereof. In Figure 3 the example shown, the powered forward flight thruster is the wing-borne ejector 108, which receives compressed air from one or more compressors 101 that can be powered by the generator 102 and / or the battery 103.

[0035] Figure 4 Illustrated is the wing-borne operation of an aircraft 100 according to an embodiment. In this configuration, the supercapacitor 110 no longer provides power, and only the turbogenerator 102 and / or the battery 103 power one or more forward flight thrusters, which can be, for example, the propeller 106, the fan 105, the wing-borne ejector 108, or a combination thereof. In Figure 4 the example shown, the powered forward flight thruster is the wing-borne ejector 108, which receives compressed air from one or more compressors 101 that can be powered by the generator 102 or the battery 103. Additionally, the supercapacitor 110 is charged by the turbogenerator 102.

[0036] Figure 5 Illustrates the wingborne operation of an aircraft 100 according to one embodiment, where battery usage is bypassed and the battery is charged. In such a configuration, the supercapacitor 110 no longer provides power, and only the turbogenerator 102 powers one or more forward flight thrusters, which can be, for example, propellers 106, fans 105, wingborne ejectors 108, or a combination thereof. In Figure 5 the example shown, the powered forward flight thruster is the wingborne ejector 108, which receives compressed air from a compressor 101 (the compressor 101 is powered by the generator 102). Additionally, the battery 103 is also charged by the turbogenerator 102.

[0037] Figure 6 Illustrates an alternative wingborne operation of an aircraft 100 using an electric ducted fan 105. In such a configuration, the supercapacitor 110 no longer provides power, and only the turbogenerator 102 powers one or more fans 105.

[0038] Figure 7 Illustrates an alternative wingborne operation of an aircraft 100 using an electric-driven propeller 106. In this configuration, the supercapacitor 110 no longer provides power, and instead the turbogenerator 102 alone provides the required power for one or more propellers 106.

[0039] One or more embodiments include a hybrid power system that consists of a combination of a generator and a supercapacitor, which together generate a large amount of power for an aircraft electric thruster.

[0040] In one or more embodiments, the generator and the supercapacitor alternately power several types of electric thrusters on the aircraft in a distributed arrangement.

[0041] One or more embodiments include a propulsion system that includes:

[0042] at least one generator, a supercapacitor, and a battery connected to an electric motor; at least one electric compressor, a duct, a thrust augmentation device, and a valve with a nozzle; at least one electric motor directly connected to at least one propeller; and at least one electric motor that powers at least one fan or rotor.

[0043] In certain embodiments, the supercapacitor supplies power for a defined period of time and is then recharged by the generator.

[0044] In one or more embodiments, the supercapacitor supplies power for a limited time and is then charged by the starting battery of the generator.

[0045] One or more embodiments include a method of flying an aircraft or hovercraft, comprising: maximizing the supply of power to a plurality of thrust generating devices that use electric motors and balance the attitude of the aircraft by supplying and regulating power to the thrust devices, and vertically hovering, taking off, and landing the aircraft as long as the capacitors can supply power; resuming power supply by the generator only when the capacitors are depleted, and charging the capacitors when the aircraft is flying horizontally.

[0046] One or more embodiments include a method of flying an aircraft or hovercraft, comprising: maximizing the supply of power to a plurality of thrust generating devices that use electric motors and balance the attitude of the aircraft by supplying and regulating power to the thrust devices, and performing a short takeoff and increasing the lift for the short takeoff as long as the capacitors can supply power; resuming power supply by the generator only when the capacitors are depleted, and charging the capacitors when the aircraft is flying horizontally; using the capacitors to enhance lift or thrust by driving a burst power motor of a thruster during flight to change the attitude, speed, and altitude of the aircraft and for rapid adjustment; maximizing the supply of power to a plurality of thrust generating devices that use electric motors and balance the attitude of the aircraft by supplying and regulating power to the thrust devices, and performing a short or vertical landing and increasing the lift for the short landing as long as the capacitors can supply power.

[0047] Although the preferred embodiments of the present invention have been illustrated and described, many changes can be made as described above without departing from the spirit and scope of the present invention. Accordingly, the scope of the present invention is not limited by the disclosure of the preferred embodiments. Instead, the scope of the present invention should be determined entirely with reference to the appended claims.

Claims

1. A propulsion system for a vehicle, comprising: At least one generator; At least one supercapacitor connected to the at least one generator; At least one battery connected to the at least one generator; At least one compressor connected to the at least one generator, the at least one supercapacitor, and the at least one battery; And At least one propulsion element connected to the compressor.

2. The system according to claim 1, wherein the at least one propulsion element comprises a propeller.

3. The system according to claim 1, wherein the at least one supercapacitor supplies power for a predetermined period of time and is then recharged by the at least one generator.

4. The system according to claim 1, wherein the vehicle comprises at least one wing, and the at least one propulsion element is connected to the at least one wing.

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