FIELD AND BACKGROUND

[0001] The present invention relates particularly, but not exclusively, to an electric vertical take-off and landing (eVTOL) aircraft. Specifically, an invention described herein may be used in an eVTOL aircraft where it is desirable to be able to load and unload the aircraft quickly.

[0002] In the art, eVTOL and VTOL (i.e. non-electric vertical take-off and landing) aircraft are known for their use as airborne taxis. The use of airborne vehicles is advantageous to avoid congestion and thus reduce travel time. Most of these existing VTOL are aircraft for 2-6 passengers and are similar to small helicopters. However, these aircraft are likely to be too expensive for day to day trips for the average person. Additionally, due to the small number of passengers the aircraft is able to transport, the empty weight fraction is larger than on a greater capacity aircraft. Thus greater electrical energy is used per passenger which consequently means higher emissions per passenger. Since the aircraft can only transport 2-6 passengers, multiple trips would be needed to transport a large number of passengers. This takes a long time and increases the complexity of air traffic management. Furthermore, due to their size and design, existing eVTOL and VTOL aircraft are not usable for transporting persons with reduced mobility.

[0003] On existing larger flying vehicles such as aeroplanes, passengers typically embark and disembark from one forward cabin door and one aft cabin door through which one passenger is able to pass at a time. Passengers must then travel down an aisle before taking their seat. Thus, the embarking and disembarking of larger aircraft takes a significant amount of time.

[0004] The invention proposes a larger aircraft, capable of seating 20-50 passengers to reduce the cost and emissions per available seat-mile or passenger-mile. This larger aircraft reduces the overall number of aircraft and trips required to transport the same number of people thus reducing the number of pilots required, the number of "vertiports" required as well as the complexity of air traffic management. The emissions per passenger are also reduced. The inventors have identified a novel way for arranging the doors such that the passengers of the eVTOL aircraft can quickly and easily embark and disembark from the aircraft. The eVTOL aircraft developed by the inventors is also accessible by persons with reduced mobility.

[0005] It will be recognised from the disclosure herein that the eVTOL aircraft of the invention, rather than being powered by rechargeable batteries, could instead be powered by an internal combustion engine or could be a hybrid VTOL aircraft. Additionally, the novel door arrangement developed by the inventors may also be used on non-airborne vehicles such as trains and buses. SUMMARY

[0006] Particular aspects and embodiments are set out in the appended claims.

[0007] Viewed from a first aspect, there is provided an aircraft comprising an elongate fuselage for containing cargo or passengers, the fuselage comprising a lower floor and an upper ceiling and opposing fuselage sides extending between the ceiling and floor. The fuselage sides each comprise at least one door which can be selectively opened and closed. The fuselage is divided into multiple zones between the fore and aft of the aircraft, each zone being associated with one of said doors adjacent to said zone and wherein the doors alternate in position between sides of the aircraft such that adjacent zones from fore to aft of the aircraft are associated with a door on an opposing side of the aircraft.

[0008] The term 'zones' is intended to mean areas. The zones within the fuselage are not physical separate from one another. According to the first aspect of the invention, an aircraft is thus provided which can be quickly and efficiently loaded and unloaded with passengers and/or cargo. This effect is achieved since the passengers or cargo are able to enter or exit through the door associated with their respective zone of the aircraft. Thus, it is not necessary for incoming passengers to wait for the previous passengers to disembark from the entire aircraft before embarking. Thus, once a first zone has been emptied, passengers can embark into this zone through its respective door before the remaining zones have been emptied. By having the doors on alternating sides of the aircraft, such that no two adjacent zones have doors that open on the same side of the aircraft, some "non-door" fuselage structure is maintained on each side. This increases the structural integrity of the fuselage.

[0009] The doors may be arranged to open generally in parallel with the fuselage side surfaces. Thus, interference between the doors and the engines or propellers of the aircraft is prevented.

[0010] The doors may be sliding doors. Again, this prevents interference between the doors and the engines or propellers of the aircraft. Additionally, by using sliding doors, the ground area required for boarding is reduced as the doors do not swing outwards but remain flush with the fuselage when they open. In other examples, non-sliding doors may be used. For example, gull-wing doors may be used.

[0011] Each door may be arranged to open to allow access to substantially the full length of the respective zone measured from fore to aft of the aircraft. Put another way, the width of the door may be the same as the length of the side of the zone into which the door provides access. Thus, if there are, for example, three rows of seats in the respective zone of the aircraft, the passengers may enter the door three abreast to enter into their respective row. Thus, passengers are able to enter more quickly than in a conventional aircraft where fore and aft doors are used through which passengers enter in single file to then move down an aisle between rows of seats. Thus, the door being arranged to provide access to the entire length of its respective zone increases the speed of access to seating and/or increases the speed at which cargo can be loaded.

[0012] The door associated with the zone proximate to the front of the aircraft may be arranged to open in a rearward direction towards the aft of the aircraft and the door associated with the zone proximate to the rear of the aircraft may be arranged to open in a forward direction towards the fore of the aircraft. In this way, the doors are prevented from having to slide beyond the length of the aircraft.

[0013] The doors may be aligned with one or more rows of seats. Thus, the passengers are able to embark through the door and enter directly into a row of seats. Thus, passengers do not have to travel down an aisle to reach their seat as in a conventional aircraft which often leads to extended time periods for embarking and disembarking. The doors being aligned with the rows of seats therefore enables rapid boarding times. The rows of seats may comprise two seats on one side of an aisle and one seat on the other side of the aisle. This enables the cabin inside the fuselage to be filled whilst minimising frontal area. Although more seats may be included per row, this will increase the frontal area of the aircraft. An aircraft with seating to fit about thirty passengers may be configured to land on exiting helipads thus existing infrastructure can be used. In other examples, custom "vertiports" and other infrastructure may be used.

[0014] The aircraft fuselage may be generally rectangular or square in cross-section. The wording 'rectangular' or 'square' are not intended to be interpreted narrowly. Instead, the crosssection of the fuselage may be generally or substantially one of these shapes. This facilitates access to the sides of the aircraft for loading.

[0015] The fuselage sides each comprise multiple doors. For example, each side may comprise two or more doors. Thus, when two doors are used on each side, passengers are able to embark onto the aircraft in four different locations spread along the length of the aircraft. In other examples, the fuselage may comprise one door on each side or more than two doors on each side.

[0016] Each of the multiple doors may be the same size. This increases the ease of manufacturing. In other examples, and depending on the length of the fuselage, the size of the doors may vary along the length of the aircraft.

[0017] The aft end of the fuselage comprises an aft door for access to the fuselage. Thus, when the aircraft is used for passengers, the aft door may be used to load luggage or cargo. [0018] The aft door may further comprise an associated ramp for access to the fuselage. This may be used for access to the aircraft by wheelchair users or those with reduced mobility. Alternatively, the ramp may be used to load rolling cargo or vehicles onto the aircraft. Due to its size, the aircraft has significantly more space and weight tolerance compared to a conventional five seat eVTOL. This allows wheelchairs and other equipment for passengers with reduced mobility to be stored with ease.

[0019] The ramp may be selectively retractable into the floor of the aircraft. In this way, the ramp remains attached to the aircraft and does not need to be attached/detached on landing/take- off. Again, this speeds up the time taken to embark/disembark from the aft door.

[0020] The aircraft may comprise a plurality of rotors, wherein at least some of the rotors are selectively rotatable between a vertical plane of rotation and a horizontal plane of rotation. When in a horizontal plane of rotation, the rotors generate lift to cause the aircraft to move off the ground. When in a vertical plane of rotation, the rotors are able to drive the aircraft in a forward direction.

[0021] In some examples, all or some of the rotors may be rotatable between the vertical plane of rotation and the horizontal plane and some may be non-rotatable between these planes. In this way, the rotors start rotating in the horizontal plane of rotation for take-off. Once the aircraft has reached the desired height, the rotors which are rotatable between the two planes of rotation may rotate to the vertical plane of rotation. Alternatively, all of the rotors may have the capability to rotate between the two planes of rotation and may be selectively rotated between these planes. For example, the aircraft may comprise six rotors, four of which are rotated between the vertical plane of rotation and the horizontal plane and two of which may not be rotated between these planes.

[0022] The aircraft may comprise three wings on each side of the fuselage. Thus, a three surface aircraft is provided. Due to this, both the front and rear wings can generate positive lift as they are either side of the centre of gravity of the aircraft. This differs from traditional aircraft where a tail generates a downforce instead of a lift which downforce must be countered by increasing the wing area. Since the front and rear wings in the present invention generate positive lift, the wing area of the aircraft can be reduced which leads to a reduced weight of the aircraft (and consequently increased efficiency) and reduced drag.

[0023] The three wings may comprise front, middle and rear wings, wherein the front wings may be anhedral and the rear wings may be dihedral. This configuration reduces the effect of wing wake interactions. [0024] Each wing may comprise a retractable control surface, wherein the control surface may be configured to be deployed at an angle with respect to the wing. The control surfaces minimise download of the rotors onto the wing during vertical flight. The download is caused by the overlap between the rotors and the wings. To reduce the force exerted on the wing by the rotors (which leads to wasted thrust), it is desirable to reduce the area overlap/blockage between the rotors and wings. The control surfaces therefore may be configured to fold downwards to do this when they are deployed. The control surfaces may be deployed close to 90 degrees or between 70 and 80 degrees with respect to the wings and retract as the rotors tilt and the aircraft transitions to horizontal flight/airplane mode. Thus, by using the control surfaces deployed at an angle with respect to the wing, this overlap is reduced.

[0025] The aircraft may comprise six rotors. These may each be attached to an aircraft wing. The rotors may be attached to a tip mounted nacelle and may be rotatable with respect to the wing. The entire nacelle with the rotors attached to it may be rotatable with respect to the wing. In other examples, the aircraft may have more or fewer wings and rotors than six.

[0026] The aircraft may be a vertical take-off and landing aircraft. Thus, when the aircraft is taking off or landing, the rotors are in 'helicopter' mode. Specifically, the rotors are facing upwards. When the aircraft is in 'airplane' mode the rotors are rotating with respect to the wings to face toward the aft end of the aircraft.

[0027] The aircraft may be powered for flight by electric motors and associated electric storage batteries. The batteries may be chargeable within the aircraft or may be removed from the aircraft for charging. When the VTOL is powered by electric motors, the rotational speed of the rotors can be more easily controlled depending on the flight mode. For example, when the aircraft is in 'helicopter' mode or vertical flight, the rotors may be controlled to rotate faster than when the aircraft is in 'airplane' mode. Electric motors allow for rapid changes in rotational speed such that, as the aircraft translates from helicopter mode to airplane mode, the electric motors can be slowed down in parallel. Thus the rotor speed can be controlled to a very tight range.

[0028] Furthermore, due to the use of electric motors, the rotational speed of the rotors can easily be controlled to limit noise. For example, the rotor speeds may be adjusted to be different from each other to avoid resonance and reduce tonal noise. Rotor speeds may also be adjusted to promote destructive interference of sound waves thus reducing noise. Rotor speed adjustments may also be matched with blade pitch adjustments to minimise performance impacts when reducing noise. Additionally, the angles of the blades can be changed in order to roll and pitch the aircraft. [0029] The electric storage batteries may be located in the upper ceiling of the fuselage. Thus, easy access for charging or removal of the batteries is provided. Additionally, if the aircraft crashes, damage to the batteries is limited due to their location in the roof. Furthermore, by storing the batteries in the roof, the cable length between the batteries and the rotor motors is reduced and thus the cable weight is reduced. This increases the efficiency of the aircraft. In other examples, the aircraft may be powered by a hydrogen fuel cell or an internal combustion engine.

[0030] Some or all of the electrical storage batteries may be contained within the sections of the aircraft connecting each wing to the aircraft fuselage. Alternatively, the batteries may be located in the wings.

[0031] The aircraft may comprise selectively removable batteries accessed from the floor, aft or sides of the fuselage. Thus, the batteries may be easily accessed for removal. Thus, when the aircraft lands, the depleted batteries may be removed for charging and replaced with fully charged batteries. Thus the aircraft can more quickly take off. Alternatively, some of the batteries may be removable for replacing/recharging whilst some are recharged in the aircraft. By reducing the number of batteries that need recharging, the stationery time of the vehicle is reduced.

[0032] The aircraft may comprise between about twenty and about fifty seats. For example, the aircraft may comprise thirty seats. Thus, the aircraft may be used as a flying bus to quickly transport passengers over short distances, for example between an airport and a city centre.

[0033] The aircraft may comprise a front wheel arrangement and at least one rear wheel arrangement, wherein the wheel arrangements are configured to be driven by an electric motor. This is used during ground taxi of the aircraft. This configuration increases safety on the ground as it is not required to have rotors turning near people. Instead of electric motors in the wheel arrangements, an electric or automated tug may be used. However, this relies on ground equipment unlike the wheel mounted electric motors.

[0034] According to a second aspect, a method of loading or unloading an aircraft is provided. The method comprises the steps of selectively opening one or more doors and (a) allowing passengers to board or disembark the aircraft from the fuselage door and/or (b) load or unload cargo through the doors.

[0035] The method may additionally comprise removing depleted batteries from the aircraft following a flight and replacing the batteries with charged batteries. Thus, it is not necessary for the aircraft to wait for the batteries to be fully charged before taking off. Instead, the depleted batteries may be swapped for charged batteries so that the aircraft can be used again straight away. [0036] According to a third aspect there is provided a vehicle comprising an elongate body for containing cargo or passengers. The body comprises a lower floor and an upper ceiling and opposing body sides extending between the ceiling and floor. The body sides each comprise at least one door which can be selectively opened and closed. The body is divided into multiple zones between the fore and aft of the vehicle, each zone being associated with one of said doors adjacent to said zone and wherein the doors alternate in position between sides of the vehicle such that adjacent zones from fore to aft of the vehicle are associated with a door on an opposing side of the vehicle.

[0037] Thus, the benefits discussed above with respect to the aircraft may be achieved on other vehicles such as buses and trains.

[0038] Other aspects will also become apparent upon review of the present disclosure, in particular upon review of the Brief Description of the Drawings, Detailed Description and Claims sections.

BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Examples of the disclosure will now be described, by way of example only, with reference to the accompanying drawings in which:

[0040] Figure 1A shows an isometric view of a vertical take-off and landing aircraft according to the invention in vertical flight mode with the doors closed;

[0041] Figure IB shows the aircraft of figure 1A with the doors open;

[0042] Figure 1C shows the aircraft of figure 1A in horizontal flight mode;

[0043] Figure 2A shows a front view of the aircraft of figure 1A in vertical flight mode;

[0044] Figure 2B shows a front view of the aircraft of figure 1C in horizontal flight mode;

[0045] Figure 3A shows a rear view of the aircraft of figure 1A in vertical flight mode;

[0046] Figure 3B shows a rear view of the aircraft of figure 1C in horizontal flight mode;

[0047] Figure 4A shows a top view of the aircraft of figure 1A in vertical flight mode;

[0048] Figure 4B shows a top view of the aircraft of figure 1C in horizontal flight mode;

[0049] Figure 5A shows a top-down internal view of the fuselage of the aircraft of figure 1A;

[0050] Figure 5B shows a cross-sectional side view of the fuselage of the aircraft of figure 1A; and

[0051] Figures 5C and 5D show cross-sectional front and rear views of the fuselage of the aircraft of figure 1A.

[0052] While the disclosure is susceptible to various modifications and alternative forms, specific example approaches are shown by way of example in the drawings and are herein described in detail. It should be understood however that the drawings and detailed description attached hereto are not intended to limit the disclosure to the particular form disclosed but rather the disclosure is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the claimed invention.

[0053] As used in this specification, the words "comprises", "comprising", and similar words, are not to be interpreted in an exclusive or exhaustive sense. In other words, they are intended to mean "including, but not limited to". [0054] It will be recognised that the features of the above-described examples of the disclosure can conveniently and interchangeably be used in any suitable combination. It will also be recognised that the invention covers not only individual embodiments but also combinations of the embodiments that have been discussed herein.

DETAILED DESCRIPTION

[0055] The present teaching relates generally to a vertical take-off and landing (VTOL) aircraft. Specifically, the teaching relates to an electric vertical take-off and landing vehicle (eVTOL).

[0056] Figure 1A shows an isometric view of the eVTOL aircraft 1 according to the invention.

[0057] The eVTOL aircraft 1 comprises a fuselage 2 and six rotors 3, three on each side of the aircraft. The rotors 3 are attached to the fuselage 2 by wings 4; front wings 12, middle wings 13 and rear wings 14. The wings 4 are attached to the top or upper ceiling of the fuselage 2.

[0058] Each rotor has five blades 5 and is attached to the wing by a tip-mounted nacelle 6. Each nacelle 6 comprises an inverter and motor (not shown) connected by cables to batteries in the fuselage for powering the respective rotor. The nacelle 6 is rotatable with respect to the wing. The fuselage 2 comprises a front wheel arrangement 7 and rear wheel arrangements 8, where each arrangement comprises one or more wheels. The wheel arrangements 8 may be powered by electric motors (not shown) for ground taxi. Alternatively, an automated or electric tug may be used.

[0059] The fuselage 2 additionally comprises two sliding doors 10 on each side. Figure 1A shows the sliding doors 10 in a closed position. Turning to figure IB, this shows the same view as in figure 1A but with the doors 10 in the open position. In other examples, more than two doors may be used on each side.

[0060] In figures 1A and IB the eVTOL aircraft 1 is in vertical flight or 'helicopter' mode. Specifically, the plane in which the blades 5 rotate is substantially parallel to the ceiling of the fuselage 2 and to the ground. In this mode, the rotation of the rotors 3 generates lift which causes the aircraft to rise off the ground. This mode is also used for landing the aircraft.

[0061] Figure 1C shows the eVTOL aircraft 1 in 'airplane' or horizontal flight mode. Specifically, the plane in which the blades 5 rotate is substantially perpendicular to the ceiling of the fuselage 2 and to the ground. In this mode, the rotation of the rotors 3 powers forward motion of the aircraft and positive lift is provided by the wings 4.

[0062] Returning to figure IB, as can also be seen in this figure, each wing comprises a control surface or flap 15. These control surfaces 15 are deployed at an angle of about 70 to 90 degrees with respect to the wing. The control surfaces 15 retract as the rotors tilt and the aircraft transitions to the 'airplane' or horizontal flight mode. The control surfaces 15 are used to reduce the overlap/blockage between the wings and the rotors. [0063] Figures 2A and 2B show front views of eVTOL aircraft 1 in helicopter and airplane modes respectively and figures 3A and 3B show rear views of eVTOL aircraft 1 in helicopter and airplane modes respectively. As can be seen from these views, the connection points between the wings and the fuselage may be substantially aligned with one another along the top of the fuselage. This is for ease of manufacture.

[0064] As can be seen from these views, the front wings 12 of the eVTOL are anhedral and the rear wings 14 are dihedral. This reduces the effect of wing wake interactions. The angle of the anhedral and dihedral wings may be between 0 and 20 degrees. For example, the anhedral wings may be at an angle of 5 degrees and the dihedral wings may be at an angle of 10 degrees. The middle wings 13 extend substantially perpendicularly from the centre of the fuselage 2. The front and rear wings 12, 14 are substantially the same length and are shorter than the middle wing 13. By having the middle wing 13 longer than the front and rear wings 12, 14, the wings 4 can be mounted closer together on the fuselage 2 whilst maintaining rotor clearance meaning the overall length of the fuselage can be reduced. This is desirable such that the aircraft 1 is able to land in smaller spaces. By reducing interference between the rotors, aerodynamic performance is improved and noise reduced. This is because the middle rotors don't fully ingest the wake of the front rotors in forward flight.

[0065] Although not shown in figures 3A or 3B, the rear of the fuselage may also have a door. This may provide access for passengers with reduced mobility via a ramp or may be for loading cargo.

[0066] Figures 4A and 4B show top views of the aircraft of figure 1A in vertical and horizontal flight mode respectively. These views show the rotation of the nacelles 6 with respect to the wings 4 as the aircraft 1 changes modes.

[0067] Figure 5A shows a top-down internal view of the cabin 11 within the fuselage 2 of the aircraft of figure 1A. As can be seen from this view, the fuselage contains multiple rows of seats 11, each row having two seats 11 on one side of an aisle and one seat 11 on the other side of the aisle.

[0068] There are two sliding doors 10 on each side of the fuselage 2. The doors 10 are shown as being of two different sizes in this figure. However, the doors may all be the same size. Each door 11 is aligned with a section or zone of the cabin 11 of the aircraft comprising two or three rows of seats. Thus, passengers enter and exit the cabin 11 through a door 10 adjacent to their respective seat. The sliding doors 10 are arranged on alternating sides of the aircraft 1 for adjacent zones of the cabin 11.

[0069] Figure 5B shows a cross-sectional side view of the cabin 11 of the aircraft 1 of figure 1A. As can be seen in this view, the seats in some rows may face toward one another. Figures 5C and 5D show cross-sectional front and rear views of the cabin 11 of the aircraft 1. Although figure 5A shows two or three rows of seats aligning with each door, more or fewer rows may align with each door of the cabin.

[0070] The various embodiments described herein are presented only to assist in understanding and teaching the claimed features. These embodiments are provided as a representative sample of embodiments only, and are not exhaustive and/or exclusive. It is to be understood that advantages, embodiments, examples, functions, features, structures, and/or other aspects described herein are not to be considered limitations on the scope of the invention as defined by the claims or limitations on equivalents to the claims, and that other embodiments may be utilised and modifications may be made without departing from the spirit and scope of the claimed invention. Various embodiments of the invention may suitably comprise, consist of, or consist essentially of, appropriate combinations of the disclosed elements, components, features, parts, steps, means, etc., other than those specifically described herein. In addition, this disclosure may include other inventions not presently claimed, but which may be claimed in future.