GB2625257A

GB2625257A - An improved propulsion system for an aircraft

Info

Publication number: GB2625257A
Application number: GB2218297.6A
Authority: GB
Inventors: Isaksen Guttorm
Original assignee: Individual
Current assignee: Individual
Priority date: 2022-12-06
Filing date: 2022-12-06
Publication date: 2024-06-19
Also published as: GB202218297D0

Abstract

An electrostatic propulsion (ESP) system to be used on the fuselage of an aircraft. Wherein the system comprises an ESP layer 20 that covers at least a portion of the fuselage, configured to generate a layer of plasma over the fuselage and accelerate the plasma to produce propulsion. Further, the system comprises one or more propellors 50, 50’ positioned downstream from the ESP layer, configured to receive the accelerated laminar air from the ESP layer to produce additional propulsion. Wherein the air from the ESP layer increased the output of the propellors, and the positioning of the propellors prevents the accelerated plasma from causing drag on the rear side of the fuselage.

Description

An improved propulsion system for an aircraft

Background

The present invention provides an improved electrostatic propulsion system for an aircraft. The use of small aircraft is becoming more common, particularly when used for short journeys and public transport, such as intercity travel in the form of Airbuses, or business travel, and sometimes for recreation. With a low-fuel, low-cost aircraft, a small aircraft can offer services to destinations that no bigger airliners can. This can enable operators to offer competitively priced airfares to destinations otherwise unobtainable for point-to-point flights. As such journeys are usually carried out often, with only a few passengers, it would be impractical to use larger aircraft.

Further, for these uses, the use of a smaller aircraft can reduce the overall amount of pollution produced when compared to larger aircraft, they may also produce less noise pollution as well, due to the use of smaller turbines and/or engines.

One problem with the increased use of such aircraft is the lack of suitable options for takeoff and landing locations, that is small aircraft used for commuting and business journeys require a suitable runway, meaning the aircraft would need to take off and land at suitable locations, such as airports or airfields, which limits their practicality. Therefore, there is a desire to have small aircraft with better acceleration to allow the use of a short runway, or better the ability for vertical or near vertical takeoff, which would remove the need for a runway entirely and instead allow the aircraft to land and take off from suitable platforms, such as a helicopter pad. This will increase the practicality of the small aircraft by increasing the number of suitable locations the aircraft can reach, for example when being used for business travel for a board meeting, vertical takeoff would allow the aircraft to land on the roof of the building where the meeting would be taking place.

It is also noted that small aircraft can suffer from the problems caused by drag, in particular 'parasite drag' caused by any breaks or changes in the surface of the aircraft, such as those around windows and doors. Though all aircraft can suffer from such drag effects, it is noted that this additional drag may cause additional wear on the aircraft, or at least affect its performance, relatively more when compared to larger aircraft, especially at high speeds. Therefore, there is a need to provide methods of reducing the overall drag on the aircraft, such as by changing the shape of the aircraft, removing windows, or the need for windows, and by looking at using steering mechanisms that produce less parasite drag, while still providing effective steering.

One way to address the pollution and noise problems can be through the use of electrical or hybrid aircraft that replaces the need for engines and fuel-burning turbines. Additionally, the use of an electric aircraft can vastly decrease the amount of noise pollution created by the aircraft, not only when taxiing across the ground, but also when performing takeoff and landing maneuvers. However, there are some problems with the use of an electric aircraft, for example, an electric aircraft may produce less thrust when compared to other propulsion methods, one way to help address this problem will be to make the aircraft from a lighter material, however, such materials do not have the optimal properties for this design, and therefore would wear more easily and may not be strong enough to withstand the impact force when the aircraft is landing or the force caused by the changes in pressure at high altitude. In other words, a semi-rigid material that is compliant enough to withstand impacts that might otherwise destroy the aircraft, but stiff enough to keep optimal aerodynamics during changing conditions of regular flight. While also being light enough to allow the small aircraft to travel at high speed, reduce the amount of thrust needed to reach such speeds, and allow the aircraft to accelerate enough to have a short takeoff distance, or to perform a vertical takeoff.

Another way the aircraft can reduce the amount of thrust needed to propel the aircraft is to shape the fuselage of the aircraft in a manner that can reduce the drag on the aircraft in flight, it is also possible that the shape of the fuselage could be designed in a manner to direct airflow to provide additional lift, or at least to reduce the amount of lift required. In some light aircraft, such as the one from US3632064A, the additional lift is provided by a secondary set of wings. However, as stated the aircraft should be as light as possible so instead this problem could be addressed by including a fuselage with curved and sloped surfaces that can improve the aerodynamics of the aircraft. Such a fuselage can be seen in lifting-body aircraft, such as those in W01997043176A1, which can take an array of shapes, at usually have small or no wings as it is the surface of the fuselage itself that generates lift. In W01997043176A1, the fuselage has an elliptical cross-section to redirect the airflow over the surface of the aircraft to generate additional lift, as opposed to the more common cylindrical fuselage shape used in many other aircraft. However, in recent times, these self-lifting fuselages have been used more often in spacecraft, than aircraft, as the specific shapes of such aircraft often generate not only lift but also a lot of drag, which can make the aircraft unstable, further alternatives such as delta wing fuselages produced faster aircraft, which can remain stable even when traveling at high speeds. It is noted that in several of these alternatives, slopes, and wedges are used to create surfaces that can redirect airflow to reduce the amount of air resistance/drag, allowing the aircraft to maintain higher speeds. Therefore, there is a need for a fuselage for a small aircraft that not only provides lift to the aircraft but can also redirect airflow in a manner that will allow the aircraft to reach and maintain high speeds and higher altitudes.

It is noted that for an aircraft designed for commercial use, there are additional factors that need to be considered, regarding the fuselage. For example, many of the current self-lifting aircraft (e.g. "flying wing") is designed for there will be a desire to include windows, so that passengers can see out of the aircraft, but the inclusion of such windows will introduce gaps, or breaks within the surface of the aircraft, which can cause additional drag, across the surface of the aircraft thereby, reducing the speed of the aircraft, as well as any lift generated by the fuselage.

With regards to the claimed aircraft, an electrostatic propulsion (ESP) system is installed on the aircraft to help address some of the issues described above, for example, such a system can produce less noise and pollution compared to the other propulsion methods. However, as shown, for example in EP0890739A1 and US20170210493A1, such ESP systems are more commonly used for spacecraft, in the form of ion thrusters. However, as the air surrounding an aircraft can interfere with such thrusters, they may not be suitable for use in an aircraft. Further, the amount of thrust delivered from such ion thrusters may not be sufficient for propelling an aircraft, especially at high speeds. Therefore, if an ESP system is to be implemented, the system would need to be redesigned to overcome these flaws. For example, the aircraft may be designed in a manner to allows the ESP system to be implemented over almost the entire upper surface of the vehicle, while also providing a means to amplify, direct and/or focus the force of the ESP system, especially during takeoff where a greater force will be needed to bring the aircraft up to speed.

Another way to reduce the overall weight of the aircraft would be to replace the motor, or thrusters used when taxiing the vehicle with an electric motor, as shown in US9227725B2 and US20130048781A1. It may be considered that the inclusion of a central electric motor could add too much weight to the aircraft, therefore another option to consider would be the inclusion of smaller electrical motors, likely placed inside the rims of the wheels directly, as these smaller motors may reduce the overall mass of the aircraft. If the smaller motors were mounted within each of the aircraft's wheels, it may be possible that the motor could remove the need for brakes on said wheels, which could help remove the need for maintenance regarding replacing the brakes due to wear over time.

It is also noted that with a small aircraft, slight differences in weight, between different portions of the aircraft, may have a significant effect on the force/impact experience by the aircraft's wheels, for example when landing or taxiing over uneven surfaces. This could lead to additional wear on the wheels or may affect the vehicle's steering, therefore, there is a need for the wheels of the aircraft to accurately monitor the weight of each portion of the vehicle, and where possible adjust the dampening of the aircraft's wheels to account for any additional force specific wheels may experience.

Additionally, it is noted that if the undercarriage of the aircraft includes one or more zo wheels, it may also include one or more electric motors, and it may be possible for said motors to be used to provide additional thrust, propulsion, and/or to reach Vr (rotation velocity) at a shorter take-off distance, and may provide lift to the aircraft when it is taking off or in flight, through other additional components coupled to the undercarriage. Though, it should be ensured that the additional driving force provided, outweighs the additional thrust needed to compensate for the weight of such components. It should also be noted that the undercarriage may include side boxes the same length as the fuselage which run along both sides of the fuselage, designed to house other components that are necessary for the aircraft, such as water, fuel, sewage tanks, batteries, or any technical devices in need of easy access.

In some embodiments, the side boxes that house the undercarriage will contain four landing wheels, two on each side, fore and aft. This arrangement serves three functions: to enable the aircraft to taxi on the ground with minimal noise pollution, to enable the aircraft to position itself with its nose facing the terminal reducing the distance to the terminal, as the wheels would allow the aircraft to reverse without assistance from pushcarts, and would allow the aircraft to achieve Vr within a shorter distance. It may also be desired that the tires used for said wheels have grip patterns, enabling better force in the first seconds on acceleration, as well as better braking properties after landing touch-down and for regenerative braking as described in more detail below.

Therefore, to address all of the problems outlined above, the claimed invention is providing an aircraft for personal, business, and commercial use. With control systems designed to further reduce weight, steering systems and fuselage designed to reduce unwanted drag forces, and an outer frame made of a material that is lightweight but still relatively strong to withstand the forces such an aircraft would experience when in common use. Said aircraft using on an electronic ESP system to reduce both noise and pollution made by the aircraft when in use. Wherein the aircraft includes new features designed to increase the amount of propulsion produced by the aircraft to compensate for the relatively low propulsion from the ESP system and provides means of reducing the drag created when using said ESP systems.

Summary:

The present invention provides a means of improving an electrostatic propulsion (ESP) system utilized by an aircraft. In particular, the present invention uses one or more propellors (props) to help increase the amount of propulsion produced by the aircraft's ESP system.

An ESP system used for propelling an aircraft would be in the form of an ESP layer that could be positioned over the aircraft's exterior, covering at least a portion of the aircraft's fuselage, but would preferably cover the entire fuselage to provide more propulsion and lift. This ESP layer comprises a plurality of anodes and cathodes designed to produce a high voltage that can be used to produce a plasma layer over the ESP layer, by charging the air surrounding the ESP layer. Once this plasma layer is formed, the charged particles within the plasma layer can then be accelerated using one of the anodes or cathodes to produce a propulsion force, this is achieved by altering the current supplied to a select group of the anodes or cathodes to produce an asymmetric electrostatic force that would accelerate the charged particles of the plasma layer in the desired direction.

In some embodiments, one of the anodes or cathodes could be replaced with a single large cathode or anode that forms a cathode/anode layer, with the other electrodes being dispersed over the anode/cathode layer. For example, the ESP layer may comprise an anode layer that covers at least a portion of the aircraft's fuselage, then a plurality of cathodes, likely in the form of cathode tufts are placed over the surface of the anode layers. This arrangement allows the spaces between the cathodes to act as a plurality of anodes, thereby providing the same effect described above. This layout may be preferable as the anode/cathode layer would likely require less power to operate compared to a plurality of anode and cathode nodes, therefore the use of the anode/cathode layer reduces the overall power demand of the ESP layer. This single layer also helps to provide the fuselage with a smooth outer surface. By making the surface of the fuselage smooth the user reduces the risk of parasitic drag forming, which may slow the aircraft when in flight.

The smooth surface would also allow the plasma layer to form more easily as the smooth fuselage surface can provide a more consistent electromagnetic force, that is to say, there is less risk of there being any inconsistencies or asymmetrical forces due to sudden gradients in the fuselage/ ESP layer shape, which would cause the plasma layer to be uneven and may cause the layer to dissipate as the charged particles are accelerated away by the asymmetrical force.

It is noted that in some cases the force generated from the ionized air within the plasma layer may be insufficient to propel an aircraft alone. This is due to the relatively small size of the charged particles that would be formed in such a plasma layer, as even in high numbers these particles produce little force. Therefore, in some cases, the aircraft may also contain a propellant, which may be sprayed over the ESP layer to provide larger charged particles within the plasma lay to provide additional force. The preferred choice for this propellent would be OH gas formed from the electrolysis of water, though other types of propellent may also be used. In some cases, the OH gas produced from the electrolysis of water may be used to drive a motor to generate the power for the ESP layer, then the exhaust of the motor would release the OH gas over the ESP layer as a propellant.

When in use the charged particles in the plasma layer are pushed or pulled by the electrodes of the ESP layer generating kinetic energy that would then push the aircraft in the desired direction. Though this process would be very useful for steering and aligning the aircraft, it may not provide enough energy to propel the aircraft to sufficiently high speeds. For this reason, it is preferable for the aircraft to include a further propulsion feature. In the case of the claimed experiment, this additional propulsion feature is in the form of a rear propellor, referred to herein as a prop.

In particular, the aircraft would be configured to have one or more props on the rear of the fuselage, or the tail of the aircraft behind the fuselage. Such a prop can be used to provide propulsion to the aircraft in the traditional manner. However, by including the ESP layer described above the claimed invention may improve the output of the aircraft's prop. Specifically, the ESP layer on the top side of the fuselage could use the anodes or cathodes to direct the ionized air of the plasma layer toward the prop. This flow of laminar air can improve the output of the prop, similarly to how the slipstream of a car can improve the acceleration of a second car directly behind the first. In this case, a stream of ionized air would be accelerated by the ESP layer towards the rear-mounted prop of the aircraft, thereby increasing the amount of air flowing through the prop and increasing the momentum of the air as it moves through the prop, both of these factors would increase the amount of kinetic energy that is transferred to the prop, which in turn would increase the amount of propulsion the prop generates, especially when compared to a system that uses the prop.

It is also noted that the use of such a prop could help to reduce drag caused by the plasma layer. Specifically, the shape of the fuselage may result in the airflow from the ESP layer causing drag as it passes over the aircraft, this can especially be the case if the aircraft is sloped towards the rear of the aircraft, such is the case with the desired dual wedge shape fuselage used in the preferred embodiment of this invention. More specifically, due to the slope at the rear of a dual wedge shape, when the air propelled by the ESP layer rolls down this slope it may cause a downward drag over the rear of the fuselage, this drag could reduce both the is propulsion and lift of the aircraft. Similarly, the point where the airflow reaches the tail of the aircraft could cause also cause drag due to the break in the surface of the aircraft where the tail connects to the aircraft. The above system helps to overcome both of these issues by first having the airflow become laminar due to the acceleration from the ESP layer, then having said laminar flow be channeled into the rear propellor of the aircraft, this way the air does not reach the break at the base of the aircraft's tail removing the drag at this location, and as the air does not flow over the fuselage as it is redirected towards the prop thereby removing the downward drag. Therefore, by using both the ESP layer and the prop together the system can remove drag that is caused when using the ESP layer or the prop alone.

It is also noted that the prop used at the rear of the aircraft can take several forms.

The simplest form for the prop would be a single propellor coupled to the center of the rear side of the fuselage. In some cases, the aircraft may use a plurality of props located along the rear side of the fuselage, for example, there may be a pair of props one positioned in each of the rear corners of the fuselage, or a row of props evenly spaced along the rear edge of the fuselage. It is noted that the prop used must provide a large amount of force to allow the aircraft to reach high speeds. For this reason, the use of a single prop may be impractical as a large prop would be needed to produce sufficient propulsion. Therefore, the use of multiple props would be preferred, these props may be arranged as separate props as described above or may be arranged co-axially. Of these arrangements, the co-axial alignment would be preferable, as the row of props would require a larger area to be implemented properly, as each prop would need a respective boom or frame which would increase the ground size of the aircraft, and would increase the mass of the end of the aircraft which could make harder to lift and steer the aircraft. It is also noted that by using a boom around the props the prop is more protected, this protection can be increased further by using a pair of side rudders on each side of the prop, thereby reducing the risk of hangar rash (a term for wear or damage caused to part of the aircraft, especially during ground travel) to the prop especially the propellor blades which are vulnerable to damage from debris kick up during landing or taxiing maneuvers. By using a boom, the props can be shielded from such damage, more so than using a frame or cowl over the props.

In contrast, a system wherein the props are arranged to be co-axially aligned could have each of the props surrounded by a single boom, this would greatly reduce the extra mass added by including these props, and the single boom also gives the aircraft a smoother shape, as the single boom could form a smooth surface between the fuselage and the tail of the aircraft, thereby producing less drag at the point the boom is coupled to the fuselage. It is noted if there were multiple booms the gaps between them would likely produce drag when the aircraft is in motion.

It is also preferable that the co-axially aligned props are coupled to a twin-spool shaft, wherein each prop has a separate shaft with one shaft positioned inside the other, thus allowing each prop to have a separate shaft while being aligned co-axially. This arrangement means that should one prop fail the other props would still be able to operate. Further, each pair of props would be able to counter-rotate, meaning that each of the props would rotate in opposite directions. In a scenario where each prop rotates in the same direction, the flow of air between the props could cause lateral drag, as the props would force the air flowing through the propellor to one side. However, by having the props counter-rotate the lateral drag from one prop would be counteracted by the rotation of the other prop, thereby allowing a more stable flight. This type of prop is referred to as a contra-rotational prop.

It is also noted that the props may include one or more rudders to allow the propulsion from the props to be steered. It is noted that if the props are not co-axial then the aircraft would require additional rudders, which may provide better control and/or faster turning, but would also increase the overall mass of the aircraft which could reduce the overall lift and propulsion produced. Therefore, it is preferable to have fewer rudders where possible which is another reason why the single boom with contra-rotational props is preferable.

Another way to produce steering would be to use the tail of the aircraft behind the props as a further rudder. In some cases, the tail may be attached to the book of the prop or the rear of the fuselage with the tail including rudders for steering the aircraft.

In the preferred embodiment, the tail would be an extension to the fuselage, wherein the sides of the fuselage extend rearwards from the rest of the fuselage, with a lateral member connecting the remote ends of these extended sides to form the aircraft's tail. This lateral member may comprise a series of morphing points, which would allow the member to flex and thereby act as a rear rudder for the aircraft. This tail may be used to provide vertical steering to the props and may need to be used in conjunction with a rudder configured to provide horizontal steering or a prop that can pivot to steer laterally.

Once the prop arrangement has been chosen the aircraft would be configured to contain one or more motors for driving the props. These props may be powered by the same engine or motor that generated the electricity for the ESP layer. The props could instead be driven by a separate motor, such as a CO2 motor, which could use a range of fuels including the HO gas used as a propellent by the ESP layer. It is noted that the HO gas that may be used by this motor can be produced from the electrolysis of water, so there would be no need to store flammable fuels within the aircraft as water is used to drive the motor. It is noted that when the props are directly driven, the length of the shafts used to rotate the props would be limited, due to the shaft needing more power to reach the required speed when the shaft is longer. Also using shorter shafts may reduce the amount of propulsion that is produced as the size of each prop would be limited based on the length of the shaft. An alternative to the direct drive motor would be to have lightweight electric motors, which generate electricity that drives the props and are sufficiently small to be mounted within the props cowling, thereby removing the shaft length as a factor and allowing longer shafts which can support more props, or larger props to generate more propulsion. It is also noted that these small motors would add less weight to the aircraft compared to the larger direct-drive motors.

In addition to the features detailed above the aircraft may include a plurality of morphing points, these morphing points are sections of the aircraft's structure that are configured to expand and contract across specific axes. These morphing points allow parts of the aircraft to adjust their shape without the need for hinges and joints which would create cracks or breaks within the aircraft surface, as such cracks may generate drag when the airflow over the aircraft impacts the broken surface.

In the case of the present invention, such morphing points may be used on the boom or cowl that surrounds the prop, the side rudders adjacent to the prop, and/or the tail behind the props. When used as part of the boom or cowl which surrounds the props these morphing points may expand the surface of the boom or cowl radially, around the axis of the prop shaft, and may be used to adjust the mass flow and/or direction of the air passing through the props. More specifically the morphing points may increase or decrease the amount of air reaching the props by exposing more or less of the prop blades. Note that the blocking of the prop outlet may be used to provide steering to the aircraft, for example by blocking, or partially blocking, the airflow ejected on one side of the prop. When used in the tail and/or the side rudders, these morphing points are used to provide steering by altering the profile of the tail or rudder to direct the airflow from the prop and ESP layers, thereby altering the direction of the propulsion force acting on the aircraft.

By using the above-mentioned system, the user can improve the propulsion of an aircraft that utilizes ESP layers. More specifically, the aircraft can utilize both an ESP layer and one or more rear-mounted propellors to provide more propulsion than using these features individually. Additionally, the positions of these features allow the laminar air from the ESP layer to be fed into the propellor, thereby increasing the propulsion produced by the propellor. This arrangement also helps to reduce the drag that may be caused by using the features individually.

Detailed Description:

The present invention is illustrated in the following drawings: Figure 1 -depicts an example fuselage with an ESP layer. Figure 2 -depicts an example of how the ESP layer functions.

Figure 3 -depicts the example fuselage with a pair of props coupled to a fuselage by a boom.

Figure 4 -depicts the example fuselage from Fig.3 with an additional tail.

Figure 5 -depicts the example fuselage from Fig.3 with additional side rudders.

These drawings comprise the following features: 10-Fuselage 12-Upper surface of the fuselage -ESP layer -Plasma layer 40 -Prop boom 50,50' -Props 60,60' -Extended side panels -Tail member -Side rudders Figure 1 shows an example of a fuselage 10 that may be used to form the aircraft described above. Please note that this example fuselage has a dual wedge shape, meaning that the fuselage comprises a front-facing and rear-facing wedge or slope, wherein the slope height decreases as you move away from the center of the fuselage. This shape is preferable as the shape provides a large smooth surface onto which the ESP layer 20 can be mounted, additionally, the slopes help to direct the airflow over the aircraft making it more streamlined and thus able to travel at higher speeds, further the airflow over the fuselage can produce some lift allowing the aircraft to self-lift to a degree. Though only this shape has been used in the drawings it should be noted that other shapes for the fuselage may be considered. As already mentioned, this fuselage 10 would have an ESP layer 20 mounted to its surface, in the depicted example the ESP layer 20 is covering the upper surface 12 of the fuselage 10, but may also cover the entire fuselage 10, or only a portion of the upper and/or lower surface of the fuselage, though the preferred ESP layer 20 would cover the entire fuselage to generate a larger airflow over the aircraft to provide lift and/or thrust to the aircraft using the fuselage 10.

The ESP layer 20 used by this aircraft would comprise one or more anodes and one or more cathodes, configured to provide a large voltage, sufficient to ionize the air surrounding the aircraft. In some cases, the ESP layer 20 may comprise a plurality of anodes and cathodes evenly distributed over the ESP layer 20. While in other cases, the ESP layer 20 may comprise an anode/cathode layer that would cover the entire ESP layer 20, with a plurality of the opposite electrodes, likely in the form of tuffs or fibers, being evenly distributed over this anode/cathode layer, for example, the ESP layer 20 may comprise an anode layer which acts as a giant anode, covered in cathode tuffs. The key element here is that the anodes and cathodes in the ESP layer 20 are evenly distributed to produce an evenly distributed electrostatic force.

This way the ESP layer 20 can generate a layer of ionized air or plasma 30 as shown in Figure 2, without the risk of said plasma layer 30 dissipating. As any inconsistencies within the electrostatic force generated by the ESP layer 20 would cause the plasma to accelerate away from the ESP layer 20, allowing the plasma layer to leak away from the aircraft and eventually dissipate.

As shown in Figure 2, when in use the ESP layer 20 supplies an equal amount of power to the anodes and cathodes within the ESP layer 20, wherein the power is sufficient to allow the anodes and cathodes to produce enough electrostatic force to partially ionize the air adjacent to the ESP layer 20, forming the plasma cloud/layer 30 over the ESP layer 20. The electrostatic force of the ESP layer would hold the plasma in place over the ESP layer 20. In some cases, the edge of the ESP layer may be configured to generate more force than the rest of the layer, possibly by having a larger density of anodes and cathodes or receiving more power relative to the rest of the ESP layer 20, this will allow the edges to produce a force barrier around the plasma layer 30 to reduce the risk of the plasma dissipating before it can be used for propulsion. Once the plasma layer 30 is formed the aircraft would be configured to use a control system to alter the power provided to the anodes and s cathode of the ESP layer 20 to create an imbalance in the electrostatic force the ESP layer 20 is producing. This imbalance may be produced by increasing the power to specific anodes and/or cathodes to increase the force they produce, or by decreasing and/or halting power to specific anodes and/or cathodes to reduce the force they produce. For example, the ESP layer 20 may be configured to decrease or stop supplying power to an edge or portion of the ESP layer to allow the plasma layer to dissipate towards the direction of the portion of the layer that has been deactivated. In another example, the ESP layer may increase the power to specific anodes/cathodes, such as increasing the power to a line of anodes, to accelerate charged particles within the plasma layer in a specific direction. As the force from the ESP layer 20 accelerates the plasma layer 30 it will increase the airflow in a certain direction to provide propulsion in the desired direction, in the opposite direction to the movement of the plasma layer 30. For example, the ESP layer 20 may accelerate the plasma layer 30 toward the rear of the fuselage 10 to provide more forward propulsion as the force would pull the aircraft forward while pushing the plasma zo backward.

One problem with using an ESP layer 20 as described above is that the amount of propulsion produced is limited by the size of the particles within the plasma layer 30. For in many cases, it may only be the electrons within the plasma layer 30 that are accelerated, and due to their low mass even with many electrons in the plasma layer 30 only a small amount of kinetic force would be generated. In these cases, the ionized particles in the plasma layer 30 would also be accelerated but due to their relatively high mass compared to the electrons, they would have only a small increase in momentum which would not provide sufficient force to propel the aircraft when compared to the force generated by the electrons. In some cases, the ESP layer 20 may include a propellent that is sprayed over the ESP layer 20 to form more charged particles that can be accelerated with the electrons to increase the amount of propulsion created from the plasma layer 30, one example of this propellent would be OH gas, made of negatively charged OH ions formed from the electrolysis of water, as the charged ions would be accelerated alongside the electrons in the plasma layer 30 to provide more momentum and create more propulsion. This propellant is also preferable as it only requires water to be stored within the aircraft, meaning there is no need to store fuels in the aircraft which can be expensive to buy and could become hazardous while being stored, further the same system used to power the ESP layer 20 can be used to provide the electricity for the electrolysis process.

It should also be noted that the force generated by the ESP layer 20 without such a propellent may be sufficient to propel a light aircraft or maintain a slow speed, or may even be used to steer the aircraft by propelling the plasma layer 30 sidewise relative to the aircraft, but would not produce sufficient force to maintain high speeds. Another potential problem is that the increased airflow generated by the ESP layer 20 may produce drag when it passes over the rear side, and rear edge of the fuselage, this drag would lower the propulsion produced by the ESP layer and may reduce the aircraft's lift when traveling through the air at high speed. The present invention seeks to remedy these problems by adding one or more propellors (props) that will work in tandem with the ESP layer 20 to provide more propulsion.

Figure 3 depicts an example fuselage 10 that uses the ESP layer 20 described above with additional props 50,50'. In this case, fuselage 10 further comprises a boom 40 that is coupled to the center of the rear side of the fuselage, wherein this boom 40 houses a pair of props 50,50' so that the props 50,50' are positioned downstream from the ESP layer 20. In this system the ESP layer 20 would function as described above, however, when the accelerated air and plasma are ejected from the rear side of the ESP layer 20, the flow would follow the edge of the boom 40 and be fed into the props 50,50' or may be pulled into the props 50,50' by the force generated by the prop's rotating blades. It is noted that such props 50,50' may be used to provide propulsion on their own by rotating the prop blades to accelerate the static air around the aircraft. However, by channeling the air from the ESP layer 20 into the props 50,50', the props 50,50' receive a large volume of laminar air which would allow the prop blades to turn faster allowing the props 50,50' to produce more propulsion when compare to props that use only the static air around the aircraft. So, by using the ESP layer 20 and the prop in tandem the aircraft can produce more propulsion when compared to using either feature on its own.

It should be noted that the depicted props 50,50' is one example of how the props may be coupled to the aircraft. In general, the system requires one or more props to be coupled to the fuselage at a position that is downstream from the ESP layer 20. So, the example in Fig.4 could be altered to have only one prop or to have additional props. Further, the props may be coupled to the fuselage by means other than a boom 40, such as using a support frame, and/or cowl to secure the props in place. There may also be several props coupled to different points of the fuselage, for example, the system may comprise a row of two or more props evenly distributed over the rear edge of the fuselage 10, with each prop being coupled to the fuselage by a respective boom, frame or cowl. Each of these options has its benefits and drawbacks; the frames allow for more flexibility in positioning the props and therefore may allow more props or props of different sizes to be coupled to the fuselage however, such frames would require several joints to attach to the fuselage, with each joint may be a source of additional drag as they will likely have exposed both heads or other breaks in the fuselage surface. It is also noted that the frame would do little to dampen the noise generated from the props, therefore said frame may include cowls over the props to act as noise dampeners, the problem with such cowls is that they may also reduce the airflow from the props and thereby reduce the propulsion produce. Additionally, the use of larger frames and/or cowls would add significant weight to the aircraft which may reduce propulsion and may lifting and steering the aircraft more difficult. In contrast, the boom can be configured as part of the fuselage structure using the same shell or skin to cover both thereby minimizing the number of breaks in the fuselage surface, also the boom may house multiple props, as shown with boom 40 in Fig.3, however the size of the prop would be limited by the size of the boom, and the boom may have a higher mass when compared to a frame configured to hold the same prop, though the reduce drag from the boom may help to compensate for the extra weight.

However, despite the different possible configurations for the systems props, it is noted that the example shown in Fig.3 is the most preferable arrangement. A system with only a single prop runs the risk of not producing sufficient propulsion as a single prop would produce less propulsion compared to a plurality of props. In the preferred embodiment, the props 50,50' are coaxially aligned, this arrangement is preferable as it allows the plurality of props to be coupled to a single boom 40 or frame, thereby reducing the mass of the overall structure. In cases where there are multiple props wherein each prop has a respective boom or frame, the mass of the props would be increased, thereby increasing the propulsion requirements for the aircraft to take off and for maintaining a high speed. Further, the additional frames and/or booms would leave gaps between the props which may cause drag and would increase the number of joints needed to attach the props to the fuselage 10, note these joints may also create drag if they leave gaps, or breaks in the surface of the fuselage 10, further increasing the aircraft's propulsion requirements. Lastly, the additional booms and/or frames would increase the aircraft's ground profile, especially as each prop would likely need to be bigger to account for the additional weight and drag, this increase in the aircraft's dimensions would mean that the aircraft would be more difficult to store within hangers, and similar buildings, and would be more difficult to maneuver when taxiing along the ground. Therefore, the arrangement that uses a single boom is preferable.

is It is also noted that the use of a boom 40 is preferable to using a frame to support the props. As the boom 40 would cover at least a portion of the front and back of the propellor blade helping to protect them from damage. In particular, using a boom 40 can reduce the risk of "hanger rash" which generally refers to wear and damage that commonly occurs to aircraft as they travel along the ground or when maneuvering into and out of hangers, as the walls of the boom act as a buffer to keep obstacles, debris and other objects that may damage the prop blades away from the props. The boom 40 also provides a smoother surface between the fuselage 10 and the props 50,50' and there are no exposed joints like there would be with a frame. Thereby reducing the drag formed by the prop structure and allowing the airflow from the ESP layer 20 to reach the prop without being slowed by such drag allowing a more efficient energy transfer between the ESP system and the props 50,50'. Further, as the preferred boom 40 would align with the fuselage's elongated axis, as shown in the figures, the static air which surrounds the boom 40 that may cause drag on the boom 40 when the aircraft is in motion, especially at the point where the boom is coupled to the fuselage 20, would be in the path of the propelled air from the ESP layer 20, as noted the movement of the plasma layer 30 from the ESP layer would cause the static air surrounding the aircraft to also be propelled, so the moving air from the ESP layer 20 would carry the static air into the prop, reducing the drag caused by the boom 40.

Further, it is preferable for the props 50,50 to be positioned co-axially as shown in Fig.3. not only does this allow multiple props to be coupled to a single boom 40, but it also allows the props 50,50' to be configured to have contra-rotation. This means that each pair of adjacent props would rotate in opposite directions. This helps to reduce any lateral drag created by the rotation of the prop blades forcing the airflow passing through the prop to the left or the right, relative to the aircraft, especially in cases where there are multiple props, for if the props all rotate in the same direction the lateral drag from each prop would be compounded together potentially causing the aircraft to drift laterally while in flight. Therefore, the contra-rotational props are preferable as the lateral drag from one blade would be canceled out by the lateral drag from the adjacent prop. For this reason, it is also preferable to have an even number of props on each boom, the most preferable number being two props, as shown with the props 50,50' in the depicted example, to help reduce the overall weight of the aircraft and to ensure there is no lateral drag as there would be an even pull towards both sides of the aircraft. In the preferred embodiment to allow the props to be co-axially aligned and to allow the props to rotate in opposite directions, the props 50,50' would be coupled to the boom 40 via a twin-spool shaft. A twin-spool shaft is configured so that each of the props 50,50' is coupled to a respective shaft, with said shafts being arranged so one shaft fits inside the other, and wherein each shaft can be powered and rotated independently from the other. This would allow each prop 50,50' to be rotated in opposite direction and would also mean that the props 50,50' do not need to rely on a single motor, reducing the risk of both props failing simultaneously.

Regardless of the arrangement of props used, the aircraft would further comprise a means for driving the props attached to the fuselage 10. One means of rotating the fuselage would be to directly drive the props 50,50' with a motor that uses the same power source as the ESP layer 20. Alternatively, the props may be driven by any suitable small motor, preferably a low-0O2 motor. A preferable motor for driving the prop would be an OH gas motor, for the OH gas used to drive the motor can be formed through the electrolysis of water stored on the aircraft and the OH gas can then be re-used as a propellent for the ESP layer 20 after being used to drive the motor. However, the problem with directly driving these props is that there would be significant power loss over the length of the prop shaft. This means that to directly drive the props the shaft would need to be smaller, which would limit the number and size of the props that could be used. This may result in the props being too small to produce the propulsion needed to allow the aircraft to maintain high speeds, and would likely mean that the props could not be arranged co-axially as described above, as each shaft would likely only be long enough to hold one prop. An alternative to this would be to have separate smaller motors coupled directly to the prop's boom 40 or cowl. This method removes the shaft length as a limit factor to the amount of power being delivered to the prop, allowing the use of a longer shaft that can support several larger props when compared to the direct drive method. It is noted that the use of larger props would increase the amount of force generated by the props and by having more props on one shaft the aircraft can counteract the lateral drag caused by the rotation of the prop as described above.

Further to the above-mentioned features, the claimed system may include additional features designed to steer the flow from the props 50,50', example of such features includes a fuselage tail and rudders, as depicted in Figures 4 and 5 respectively. The purpose of these features would be to direct the airflow exiting the props 50,50' either vertically or horizontally to direct the propulsion force produced by the prop to steer the aircraft laterally or alter the lift of the aircraft.

Figure 4 provides an example of how a tail may be added to the fuselage 10 to assist in steering the aircraft, it is noted that the tail would need to be positioned downstream from the props 50,50' in a position where the steering member of the tail, such as tail fins, would be in the path of the airflow coming from the props 50,50'. The problem with including such a tail is that the normal design for an aircraft tail would couple to the fuselage 10 at the same point where the boom 40 is attached. In some cases, the tail may be configured to house the boom 40 and props 50,50', effectively having a portion of the tail envelop the prop boom 40 so that they may both be attached to the rear of the fuselage 10. However, such a design would require a larger tail which would significantly increase the mass of the aircraft and would reduce the propulsion of the props 50,50' as the tail would act as a cowl or frame over the boom 40 that would disrupt the airflow from the prop and produce breaks in the aircraft surface that may cause drag. An alternative may be to have a tail coupled to the center of the fuselage 10, like the boom shown in Fig.3, and have a separate prop on each side of the tail, but this would again increase the mass of the aircraft as they would need to be two booms and additional motors to drive the second boom, additionally, the gaps between the tail and the boom could create drag when the airflow passes over the rear of the fuselage 10.

Therefore, the preferred embodiment of the tail is the one shown in Fig.4, this tail is formed by extending the side panels 60,60' of the fuselage 10, then coupling the aft ends of the extended side panels 60,60' with a horizontal member 70 which acts as the tail fin and steering means for this tail design, by configuring at least a portion of the member 70 to pivot to rotate relative to aircraft. It would also be preferable for the tail member 70 to comprise morphing points, wherein the points in the member can expand and contract to change the profile of the member 70, to provide vertical steering to increase or decrease the aircraft's lift. By using these morphing points, the aircraft remove the need for separate joints within the tail which would create breaks within the member's surface which can cause drag as the airflow passes over the tail member 70. It is noted that this design removes most of the additional mass caused by the other tail designs and can be incorporated with the preferred embodiment of the props 50,50' without reducing the output from the props 50,50'. It is also noted that this tail design would not produce as much drag as the alternative tail designs as the extended side panels 60,60' mean there are no breaks in the surface of the fuselage 10 and the morphing points reduce any drag created by the tail member 70.

Figure 5 depicts an example of how side rudders 80 could be added to the preferred embodiment of the prop 50,50'. It is noted that the tail shown in Fig.4 would primarily provide steering in the vertical direction, though the morphing points could be used to alter only one side of the tail member to provide some lateral steering. However, by including side rudders positioned on either side of the prop boom 40 the aircraft can provide lateral steering more reliably. In this case, the rudders 80 would be configured to pivot horizontally relative to the props 50,50' and fuselage 10, to allow the sides of the rudders 80 to act as a windbreak that may direct the airflow ejected from the props 50,50' to the left or right of the aircraft to provide lateral steering. As with the tail, it is preferable for these rudders 80 to include morphing points to allow the rudders to actuate without the need for a joint, or hinge point, as such joints would create breaks in the rudder's surface that may cause drag when the airflow passes over the rudder 80. In some cases, these rudders may be formed by extending the rear of the fuselage or the walls of side boxes coupled to the underside of the fuselage rather than being separate structures to remove the need for such joints to the fuselage. The aft ends of the rudders 80 may use morphing points to allow the rudders to actuate without joints or breaks in the rudders' surface, It is also noted that each prop would require a respective pair of rudders, when the props 50,50' are not co-axially aligned, therefore by using the preferred arrangement the need for additional rudders are removed thereby reducing the overall weight of the aircraft.

It is also noted that the morphing points used in these steering features may also be used on the props to control the airflow entering and leaving the prop. Specifically, the morphing points may be used as part of the boom 40 or cowl which surrounds the props, wherein these morphing points may be used to adjust the volume of air entering and leaving the props 50,50'. More specifically the morphing points may increase or decrease the size of the prop intake by exposing more or less of the prop blades, thereby increasing or decreasing the amount of air entering the prop. The morphing points may similarly expand and contract to shield the rear of the props to limit the amount of propulsion being produced by disrupting or blocking the airflow ejected from the props 50,50'. Note that the blocking of the prop outlet may be used to provide some steering, for example by blocking, or partially blocking, the airflow ejected on one side of the prop in the same manner as the side rudders 80. The morphing points may also be incorporated into the blades of the props 50,50' so that the blade profiles can be adjusted to alter the amount of propulsion supplied by the props 50,50' without altering the speed of the prop motor.

Lastly, the aircraft would include additional control systems for controlling each of the ESP layer 20 and the one or more props coupled to the fuselage 10. Wherein this control system would be able to control the electrical power being supplied to both the ESP layer 20 and the means for driving the props 50,05'. Wherein the controller may be configured to adjust the power to a specific part of the ESP layer 20, such as changing the power supplied to specific anodes or cathodes to direct the motion of the plasma layer 30 formed by the ESP layer 20. The controller would also be configured to independently control the speed of each prop coupled to the fuselage 10, allowing for more refined control over the propulsion produced by the aircraft. This control system may also be configured to control the steering means coupled to the fuselage 10, such as the tail member 70 and side rudders 80. The system may also control the systems configured to generate and eject the propellent used by the ESP layer 20. As noted the preferred propellent for the ESP layer is OH gas which may also be used to drive the motor for the props 50,50', allowing the aircraft to have a single system for generating the OH gas from water, which can then be supplied to one or both of the ESP layer 20 and prop motor. This control system may also comprise a series of sensors for monitoring the condition and outputs of each of the propulsion features, allowing the user to adjust the output of the ESP layer 20 or props 50,50' based on the sensor reading. In some cases, the control system may be configured to make such adjustments automatically, when the sensor readings fall outside present thresholds, for example, the system may increase the power to the ESP layer 20 and/or the prop motor to increase the propulsion produced if the prop speed falls below a threshold value, or the control system may adjust the power to one side of the ESP layer 20 if the sensors determine that the aircraft is drifting or that the steering features are not sufficiently turning the aircraft, or to counteract any turbulence acting on the aircraft. The system may also control any morphing points within the aircraft, which may be powered by a separate motor or the same means as the ESP layer. The control system may also be configured to automatically adjust the power supplied to the propulsion features based on the current stage of the aircraft's flight, for example changing the output of the ESP layer 20, and/or props 50,50' during take-off, or landing procedures.

By using the above-mentioned system, the propulsion of an aircraft that utilizes ESP layers can be improved. More specifically, the aircraft can utilize both an ESP layer and one or more rear-mounted propellers in tandem to provide more propulsion than using either of these features individually. The positions of these features allow the laminar air generated and accelerated by the ESP layer to be fed directly into the propellor, thereby increasing the propulsion produced by the propellor by increasing the airflow into the prop and by streamlining and accelerating the airflow into the prop to help transfer more momentum into the propellor blades. This arrangement also helps to reduce the drag that may be caused by using the features individually. More specifically, when the airflow from the ESP layer passes over the rear edge of the fuselage it may produce a downward force that would reduce the lift of the aircraft and may also produce a drag on the rear of the fuselage, however by redirecting the airflow into the prop this drag can be removed. Further, the break in the fuselage surface where the prop boom is coupled to the fuselage can also be a cause for drag as the end of the boom disrupt the airflow over the fuselage, however, the ESP layer can be used to accelerate and direct the airflow around the boom and towards the props within the boom, thereby reducing the drag caused by the boom.

Claims

Claims: 1. An aircraft comprising an electrostatic propulsion (ESP) system and at least one propellor (prop 50,50'); wherein the ESP system comprises an ESP layer 20 configured to generate electrostatic forces to form a layer of plasma 30 over the ESP layer 20, and to accelerate the particles within the layer of plasma 20 in a desired direction; wherein the ESP layer 20 covers at least a portion of a fuselage 10 of the aircraft; and wherein the at least one prop 50,50 is positioned rearward of the fuselage 10, downstream from the ESP layer 20, and is configured to receive the laminar airflow from the ESP layer 20.
2 The aircraft of claim 1, wherein the ESP layer 20 comprises a plurality of anodes and cathodes.
3. The aircraft of claim 1, wherein the ESP layer 20 comprises an anode layer with cathode tuffs placed over the surface of the anode layer.
4. The aircraft of any preceding claim wherein the ESP system includes a propellent that is sprayed over the ESP layer 20 at a position upstream of the prop 50,50'.
5. The aircraft of claim 4 wherein the propellant comprises HO gas.
6. The aircraft of any preceding claim wherein the one or more props 50,50' are coupled to the fuselage 10 via a respective support frame.
7. The aircraft of claims 1 to 5 wherein the one or more props 50,50' are coupled to the fuselage 10 by a boom 40.
8 The aircraft of any preceding claim wherein the one or more props 50,50' include a respective cowl.
9. The aircraft of any preceding claim wherein the aircraft comprises a plurality of props 50,50' that are positioned co-axially.
10. The aircraft of claim 9 wherein the co-axially aligned props 50,50' are mounted to the fuselage 10 via a twin-spool shaft.
11. The aircraft of claims 9 and 10 wherein the co-axially aligned props 50,50' are configured to be contra-rotational, wherein each pair of adjacent props rotate in opposite directions.
12. The aircraft of any preceding claim wherein the one or more props 50,50' are to driven by a motor aboard the aircraft.
13. The aircraft of any preceding claim wherein the one or more props 50,50' are driven by a motor coupled to the boom 40 or cowl of each prop.
14. The aircraft of claims 12 and 13 wherein the motor is an OH gas-driven motor.
15. The aircraft of any preceding claim wherein the one or more props 50,50' comprise a respective set of side rudders 80.
16. The aircraft of any preceding claim wherein the fuselage 10 includes a tail that is positioned downstream from the one or more props 50,50'.
17. The aircraft of claim 16 wherein the tail is formed by extending the sides 60,60' of the fuselage 10 rearward with the ends of the extended sides 60,60' coupled together by a horizontal member 70.
18. The aircraft of claims 16 and 17 wherein the tail comprises a plurality of morphing points to provide steering to the aircraft, by morphing the shape of the tail.
19. The aircraft of any preceding claims wherein the one or more props 50,50' include a plurality of morphing points.
20. The aircraft of claim 19 wherein the morphing points are positioned in one or more blades of the props 50,50'.
21. The aircraft of claim 19 or 20 wherein the plurality of morphing points are positioned in the boom 40, or cowl coupled to each of the props 50,50'.
22. The aircraft of any preceding claim, wherein the aircraft comprises a control system configured to control the power used to operate the ESP layer 20 and to drive the one or more props 50,50'
23. The aircraft of claim 22, wherein the control system is configured to automatically adjust the output of the ESP layer 20 and/or one or more props 50,50' based on the current stage of the aircraft's flight.
24. The aircraft of claims 22 and 23, wherein the control system further comprises one or more sensors configured to monitor the output of the ESP layer and props 50,50', and/or the motion of the aircraft; and wherein the control system is configured to adjust the output of the ESP layer and or props 50,50' based on the readings from the sensors
25.A method of using the aircraft of claims 1 to 24 wherein the ESP layer of the aircraft generates a layer of plasma over the ESP layer; the anodes or cathodes of the ESP layer accelerate the charged particles of the plasma layer to provide propulsion to the aircraft; wherein the air and plasma above the ESP layer are accelerated towards the one or more props to provide laminar air to the prop for increased propulsion.
26. The method of claim 25 wherein the boom or rudders coupled to the prop are rotated to direct the propulsion from the props.
27. The method of claims 25 and 26 wherein the tail of the aircraft downstream from the prop can morph and/or rotate to direct the propulsion from the props.
28. The method of claims 25 to 27, wherein the method further comprises spraying a propellent over the surface of the ESP layer towards the one or more props.
29. The method of claims 25 to 28, wherein the props include a cowl or boom with morphing points, wherein the cowl or boom is configured to morph to control the volume of the prop inlet, thereby controlling the volume of air entering the prop.