VTOL aircraft with spinning mode

Abstract

An aircraft featuring at least one lifting rotor, one or more lifting airfoil-shaped wings, and at least one thrust-generating device capable of spinning the wings or the aircraft with the wings around its centre axis, characterised by the aircraft being able to change its orientation during flight by varying the aerodynamic lift of at least one of the airfoil-shaped wings by a device or a combination of devices including but not limited to, aileron or wing tip control surfaces, orwing pitch modulation, or wing profile modulation, or by modulating the lift produced by the lifting rotors around the aircraft centre of rotation, or a combination of said devices, and with a controller for the aerodynamic lift modulating device.

Description

[0001] VTOL AIRCRAFT WITH SPINNING MODE

[0002] Field of the invention

[0003] The present invention relates to vertical take-off and landing (VTOL) aircraft structures, specifically to aircraft equipped with lift-producing rotors that enable take-off and landing without the need for forward motion, thereby eliminating the requirement for a runway. to the invention

[0004] Traditional fixed-wing aircraft are known for their capabilities in terms of safe flight procedures, high speeds, extended range, and significant payload capacity. However, these aircraft require a runway for take-off and landing operations and lack the ability to hover, which restricts their operational versatility and limits their use in various environments. As a result, their development and adoption have been constrained in scenarios requiring hover or purely vertical flight.

[0005] In contrast, conventional rotary-wing aircraft, such as helicopters, utilise rotating lift devices such as rotors or propellers that generate lift by spinning around their axes. This design grants rotary-wing aircraft the ability to hover and achieve a high degree of flight manoeuvrability. Due to these attributes, helicopters have seen widespread use in numerous applications throughout the past century. In contrast to fixed wing aircraft rotary winged aircraft typically require a higher power to lift ratio and the rotor design makes it difficult to scale them to the size which is achievable through fixed wing aircraft.

[0006] A number of proposals and aircraft designs combining both the vertical takeoff and landing capability of rotary winged aircraft and the better aerodynamic efficiency of fixed winged aircraft have been made. These so-called transitional lift or lift and cruise aircraft combine benefits of both types but are still limited in their payload due to the lower aerodynamic efficiency of the rotary wing aircraft mode deployed during take off and landing.

[0007] More recently a new class of aircraft has been proposed which operates in a similar fashion to the lift and cruise aircraft but instead of transitioning into a linear forward flight path when transitioning from the vertical lift to the horizontal flight mode it is transitioning into a spinning mode. The wings on these aircraft are arranged in a way that one or more winged sections create aerodynamic lift in the spinning mode significantly increasing the aerodynamic lift efficiency.

[0008] One embodiment of this new type of aircraft has been to use the lifting rotors as the device which generates the spinning motion of the wing and also varies the lift it produces in phased relationship with revolutions of the rotatable body by modulating the thrust of individual lifting rotors cyclically.

[0009] This type of operation could help in increasing flight time or could allow it to lift up additional cargo as an underslung load after transitioning into the spinning mode of operation whereby aerodynamic lift efficiency is improved.

[0010] The present invention aims to provide an improved aircraft including advantageous features of both fixed-wing and rotary-wing aircraft. Specifically, it combines the aerodynamic efficiency and flight control capabilities of fixed-wing aircraft, which utilise airfoil-shaped wings with control surfaces such as ailerons or wingtip devices, with the lift and thrust-generating characteristics of rotary-wing aircraft. This novel approach uniquely allows for the incorporation of rotating wings that spin around their own axes, similar to rotary-wing mechanisms, while employing ailerons or other lift modulating devices for flight control.

[0011] This innovative combination diverges from traditional helicopter designs that rely on collective and cyclic pitch control. Instead, the invention proposes a method of flight direction control utilising ailerons, thus merging fixed-wing and rotorcraft technologies in a distinctive manner to enhance VTOL capabilities.

[0012] Furthermore rotorcraft traditionally use mechanical linkages between the engine and the rotors which are often spinning shafts with flexible joints. More recently rotorcraft architecture linking one or more central power sources in form of batteries or engine power generators to the rotors by means of electrical lines have been presented. While this type of architecture offers flexibility in design it typically suffers from the high weight of such transmission systems.

[0013] Some aspects of the invention also use a hydrostatic transmission system to facilitate the proposed new system architectures. In the field of hydrostatic transmission significant advances have been made over the past decades through the introduction of Digital Displacement synthetically commutated pump technology (Digital Displacement is a trade mark). This technology further advances control and efficiency of hydraulic pumps by means of installing control valves on each pumping cylinder and deploying a microcontroller enabling and disabling these valves controlling the output of the machine.

[0014] It is in this context that the present inventions have been devised.

[0015] Summary of the invention

[0016] According to a first aspect of the invention, there is provided an aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, and a controller configured to change the orientation of the aircraft during flight by modulating the aerodynamic lift of at least one airfoil-shaped wing (9) in phased relationship with revolutions of the rotatable body. The controller may be configured to modulate the aerodynamic lift of at least one airfoilshaped wing (9) by controlling one or more of: at least one aileron (8), at least one wing tip control surface (4), a wing pitch modulator (30) or wing profile modulator in phased relationship with revolutions of the rotatable body.

[0017] According to a second aspect of the invention there is provided an aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoilshaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, and a controller configured to change the orientation of the aircraft during flight by modulating the lift of at least one lifting rotor (12).

[0018] It may be that the lifting rotors (12) are fixedly coupled to and rotate with the rotatable body and the controller is configured to change the orientation of the aircraft during flight by modulating the lift of at least one lifting rotor (12) in phased relationship with revolutions of the rotatable body.

[0019] It may be that the controller is also configured to change the orientation of the aircraft during flight by modulating the aerodynamic lift of at least one airfoil-shaped wing (9) in phased relationship with revolutions of the rotatable body. Thus, the aircraft may be according to the first and second aspects of the invention.

[0020] In a third aspect, the invention extends to an aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, and a controller configured to operate the aircraft in at least:

[0021] (i) a first mode in which the at least one lifting rotor (12) is used for vertical take-off or landing and attitude control;

[0022] (ii) a second mode in which the rotatable body is spun around the axis of rotation and the one or more lifting airfoil-shaped wings (9) create some or all of the lift required to take off or stay airborne; and

[0023] (iii) a third mode in which the one or more lifting airfoil-shaped wings (9) create some or all of the lift required to take off or stay airborne, and wherein the one or more thrust generating devices (6) and / or at least one lifting rotor (12) provide directional flight propulsion. In a fourth aspect there is provided an aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, and a controller configured to independently control the at least one lifting rotor (12) and the at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, typically wherein the at least one thrust-generating device (6) is a rotor (6) mounted to a lifting airfoil-shaped wing (9).

[0024] Further optional features of each of the four aspects (which may be combined) are discussed below.

[0025] It may be that the orientation of the aircraft which is changed is a pitch or roll of an axis of the aircraft. It may be that the orientation of the aircraft which is changed is a pitch or roll or yaw of an axis of the aircraft. The axis may for example be the axis of rotation, or a central axis (e.g. of a fuselage) which is vertical when the aircraft is on level ground.

[0026] The axis of rotation of the rotatable body is typically perpendicular to the plan of rotation of the airfoil-shaped wings. The axis of rotation of the rotatable body may be vertical while the aircraft is hovering.

[0027] Typically, the rotatable body and airfoil-shaped wings (9) are separate to the at least one lifting rotor (12).

[0028] The present invention relates to a new class of aircraft that integrates features of both fixed-wing and rotorcraft designs. Specifically, the invention combines components commonly found in fixed-wing aircraft, such as airfoil-shaped wings with control surfaces such as wingtip control or aileron control, with elements typically seen in multirotor aircraft, including lifting rotors for vertical take-off and landing and thrustgenerating devices like propellers.

[0029] The thrust generating devices are capable of providing a force which causes a rotational motion of the wing about its own axis in order to produce aerodynamic lift. The primary advantage of this configuration is that it leverages the efficiency of the large lifting surface of the wing, allowing it to generate lift in a manner akin to that of a helicopter rotor. Consequently, this eliminates the need for a runway, as the aircraft can perform vertical take-off and landing (VTOL).

[0030] A distinguishing feature is the utilisation of ailerons or similar control mechanisms to vary the aerodynamic lift of the rotating airfoil-shaped wing in phased relationship with revolutions of the rotatable body. Thus, the lift generated by the rotating airfoil-shaped wing varies with the azimuthal angle of the wing (relative to an arbitrary zero angle such as a direction of travel, or north etc.), and this is typically repeated cyclically. This innovative approach provides directional control of flight comparable to a helicopter, but without the need for traditional cyclic or collective pitch mechanisms typically employed in rotorcraft.

[0031] It is proposed that the aircraft will be controlled by modulating the lift generated by the winged section (9) during each rotation. The winged section (9) will incorporate aerodynamic control mechanisms that enable it to produce varying levels of lift across different segments of the azimuth, allowing for precise attitude control. This modulation of lift will enable the aircraft to maintain a horizontal orientation or tilt in various directions relative to the horizontal axis, thereby generating forward or lateral motion.

[0032] Typically, the controller comprises at least one processor and memory storing program code executed by the controller.

[0033] The controller may be a flight controller. The controller may manage the aircraft's direction and position relative to the ground. The controller may either receive preset flight path data or track the current flight path in real time. It will determine the aircraft’s orientation and position using a combination of sensors, including but not limited to magnetic compass, gyroscope, vision-based systems, Lidar, Radar, GPS, or other sensory elements. The orientation may be used to determine the current azimuthal angle of the rotatable body. The controller may be configured (e.g. programmed) to determine the current azimuthal angle of the rotatable body (relative to a zero). The controller may receive position signals indicative of the angle of the rotatable body relative to a non-rotating component, for example using a position sensor. The controller may account for gyroscopic forces resulting from the spinning motion of the aircraft. These forces should be compensated for in order to achieve the desired tilt angle. The controller may be programmed to adjust the lift modulation out of phase with the desired tilt angle as necessary to account for the gyroscopic effects.

[0034] It may be that, once the desired lift profile for each revolution has been determined, the flight controller will control the aerodynamic lift generated by the winged section relative to its rotational position. The modulation of lift can be achieved through various methods, such as aileron control, wingtip control surfaces, full wing pitch control, wing profile modulation, or other means that vary the lift of the winged section.

[0035] It may be that phased lift control is achieved through lift-generating propellers arranged horizontally. These propellers may vary their lift output in phase with the lift modulation commands from the controller. The propellers may produce positive lift, negative lift, or no lift at various points (azimuthal angles) during the revolution, which could be achieved by adjusting their speed or pitch angle of the lift propeller. These propellers may also serve as the same propellers used during the aircraft's non-spinning operational mode.

[0036] Additionally, lift from the winged section (9) may be increased or decreased in one or more segments of the rotation, or increased in one segment and decreased in an opposing segment.

[0037] It may be that the altitude of the aircraft is controlled by modulating the average lift generated by the winged section (9) throughout each revolution. This control method allows for rapid altitude adjustments during landing, takeoff, or load pickup, by utilizing the aircraft’s rotational inertia. An increase in lift may be achieved at the cost of increased drag on the winged section (9), with the aircraft’s inertia sustaining the spinning motion until the thrust-generating rotors (6) restore the rotational speed to its target value.

[0038] It may be that the aircraft includes a centralised power unit, which may be a combustion engine, battery, fuel cell or other source, connected to a distributed propulsion transmission system. While electric variants of propulsion systems have been previously explored, the aircraft may employ lightweight, high-power-density Digital Displacement hydraulic transmission components to efficiently distribute power. This distribution may extend to the lifting rotors, thrust-generating devices, and control surfaces, powered by one or more common or separate power units, which may or may not be centrally located within the fuselage.

[0039] It may be that take-off is achieved either solely through the use of the lifting rotors or by utilising the lift generated by the rotating airfoil-shaped wing. It is anticipated that during initial take-off, the aircraft will primarily rely on the lifting rotors.

[0040] It may be that, once in flight, the thrust-generating devices, which may be the same as the lifting rotors, will engage to initiate the rotation of the airfoil-shaped wing, thereby generating additional lift. This design enables the aircraft to carry significantly heavier cargo loads, broadening its potential applications in both civil and military logistics.

[0041] It may be that cargo can be underslung and securely attached to the vehicle. These loads are designed to be winchable, capable of being raised or lowered, and can be released as needed. Furthermore, the cargo may be actively positioned to remain stationary relative to the rotatable body and wings, preventing it from rotating with the wings. The aircraft may comprise a non-spinning lower portion. Cargo may be attached to the non-spinning lower portion. The non-spinning lower portion may be coupled to the rotatable body by a rotary actuator to avoid rotation of the lower portion when the rotatable body is rotating. In some embodiments, the at least one lifting rotor is fixedly mounted to the non-spinning lower portion and the rotatable body is rotatably mounted relative to the non-spinning lower portion and the at least one lifting rotor.

[0042] The winged section may feature a symmetric profile, allowing it to generate thrust in both directions depending on the angle of attack. This capability can be further enhanced by adding aerodynamic control surfaces at the tip or tail, or other mechanisms to modify the profile of the winged section. This arrangement enables the aircraft to operate in three distinct modes.

[0043] First mode: Vertical take-off - In this mode, one or more thrust-generating propellers are oriented upward, enabling vertical lift. Second mode: Spinning flight- In this mode, the winged sections rotate, with the profile and thrust-generating propellers oriented in opposing directions, causing the aircraft to spin.

[0044] Third mode: Horizontal flight - In this mode, the two winged sections and some or all of the thrust propellers are directed in the same direction, allowing the aircraft to transition into horizontal flight.

[0045] The arrangement shown in Figure 9 illustrates two thrust propellers, but a different number of thrust propellers may also be used. The thrust propellers may be positioned along the nose of the winged section or on either side of the winged section using mounting structures to provide greater stability during vertical flight. Additionally, it is conceivable that some of the thrust rotors could be mounted on the winged section, while others may be attached to the main fuselage via a mounting frame structure.

[0046] The ability to transition into forward flight mode allows the aircraft to achieve higher cruising speeds and cover longer distances. With both winged sections aligned in the same direction during horizontal flight, the aircraft can be designed as a flying wing, utilising control surfaces installed on the winged section to stabilise the aircraft. It is also conceivable to add additional control surfaces to the main fuselage or the winged sections. These may include, but are not limited to, a horizontal stabiliser with an elevator, and a vertical stabiliser with a rudder , which could be arranged either in front of or behind the main winged sections.

[0047] It may be that all or some of the lifting rotors (12) and thrust-generating devices (6) are driven by hydraulic motors (11), which may be connected to one or more common or separate variable flow displacement pumps (1), which may be synthetically commutated, (e.g. of Digital Displacement type), and one or more common power units (2), which may be combustion engines, through hydrostatic transmission lines (7), with the power unit (2) located in the central fuselage (14).

[0048] The one or more synthetically commutated pumps may comprise one or more working chambers of cyclically varying volume and one or more electronically controlled valves which are controllable on each cycle of working chamber volume to determine whether the working chamber carries out an active cycle in which it makes a net displacement of hydraulic fluid or an inactive cycle in which it makes no net displacement of hydraulic fluid. The one or more synthetically commutated motors may comprise one or more working chambers of cyclically varying volume and one or more electronically controlled valves which are controllable on each cycle of working chamber volume to determine whether the working chamber carries out an active cycle in which it makes a net displacement of hydraulic fluid or an inactive cycle in which it makes no net displacement of hydraulic fluid.

[0049] A suitable hydraulic circuit is described in in EP3450312 (Caldwell). The aircraft may be a multi-rotor aerial vehicle as described in EP3450312 (Caldwell), the contents of which are hereby incorporated by this reference.

[0050] It may be that at least one airfoil-shaped wing (9), or one or more counterweights for balance, or a combination of both, are arranged around the circumference of the main fuselage (14) on one or more horizontal planes.

[0051] It may be that one or more of the lifting devices (12) and one or more of the thrustgenerating devices (6) spinning the rotatable body about its centre of rotation are the same devices. It may be that said devices transition from vertical to horizontal thrust orientation during mode changes by means of tilting the airfoil shaped wing (9) or by tilting the lifting and thrust generating rotor (12) and (6) or by another means.

[0052] It may be that at least one lifting rotor (12) is mounted on the airfoil-shaped wing (9) or to the wing by an outrigger (21) or attached to the fuselage (14) via a boom arm (10) or other device, characterised in that said lifting rotor (12), boom arm (10), outrigger (21) or airfoil-shaped wing (9) is foldable or extend to change the size of the aircraft for transport.

[0053] It may be that the aircraft has a central fuselage section to house individual components, characterised in that the central fuselage (14) and any lifting rotors (12) attached to it are non-spinning relative to the rotation of the rotatable body (and thereby one or more airfoil-shaped wings (9)) by use of a bearing (53) or other device controlled in an active or passive manner. It may be that at least one lifting rotor (12), or at least one airfoil-shaped wing (9) or, a combination of both, operates at a fixed rotational speed and modulates its lift using collective and cyclic pitch control mechanisms.

[0054] It may be that there is only one central lifting rotor (12) with active pitch control located in line with the central fuselage (14).

[0055] It may be that at least two lifting rotors (12) or at least two airfoil-shaped wings (9), or a combination thereof, rotate in a contra-rotating configuration about a common rotational axis, or with the rotational axes offset by a distance.

[0056] It may be that the aircraft can autorotate for a safe landing in the event of failure of one or more power units. This may be by at least one of but not limited to the following means, pitch angle control; airfoil profile modifications by deforming leading or trailing edges of by active means, actuated by motors or other devices, or by passive means through centrifugal, aerodynamic, or gravitational forces, typically under the control of the controller.

[0057] It may be that the aircraft is operable underwater with the power unit (2) connected to an underwater breathing apparatus, compressed air tank, or other device, further characterised by using one or more underwater thrust-generating devices, which may be the same or a separate devices to one or more of the lifting rotors (12) or one or more of the thrust-generating devices (6), or a combination thereof.

[0058] It may be that the winged section (9) can be pitched to point the thrust generating rotors (6) in opposing direction thereby placing the aircraft into a spinning mode or can be kept in the same orientation with the ability of the aircraft to transition into a forward flight mode, with the airfoil sections being able to produce lifting thrust in both directions depending on the forward flight mode or the spinning mode.

[0059] It may be that the winged profile (9) is of symmetric geometry in order to achieve thrust in both directions depending on the angle of attack, or is of a type which can morph into a non symmetric profile by means including but not limited to a wing tip control surface (4), a wing tail control surface (8) or other means to change its wing profile. It may be that the aircraft has additional features to improve stability and flight control in forward flight which could be but not limited to a horizontal stabiliser and elevator control surface and a vertical stabiliser and rudder control surface.

[0060] It may be that a cargo load is connected, or connectable, to the aircraft rigidly or non- rigidly in an underslung manner or other method. It may be that the cargo load can be winched up and down using a motor or other device, and the position of the underslung cargo load can be actively controlled by means of a mechanical actuator, thruster, or other device, and the cargo load may be non-spinning relative to the rotating airfoilshaped wing (9) by use of an active or passive device of bearing (53) or other type.

[0061] It may be that one or more buoyancy devices in the form of floats (71 , 72) are attached to the central fuselage (14) or wings (9) allowing the aircraft to take off, land, and manoeuvre on water, with one or more hydrofoils used to facilitate transition into the spinning mode on water, and at least one flotation device which may be mounted at the tip of a wing to improve balance.

[0062] It may be that the aircraft transitions directly into the spinning mode on the ground by rotating about a landing gear that does not rotate, using a bearing (53) or other device, alternatively the landing gear rotates with the aircraft on the ground by use of wheels.

[0063] It may be that the attitude control and stability of the aircraft in the second (spinning) mode of operation requires cyclic modulation of lift in phased relationship with revolutions of the rotatable body, which may be achieved by one or more of the following means, wingtip control surfaces (4) or ailerons (8); pitch angle control (30); airfoil profile modifications by deforming leading or trailing edges, actuated by motors or other devices, or by passive means through centrifugal, aerodynamic, or gravitational forces; or by modulation of one or more lifting rotors (12) and thrustgenerating rotors (6).

[0064] It may be that the attitude control and stability of the aircraft in the third mode of operation (as an airplane) is achieved by one or more of the following means, horizontal stabiliser (93) and elevator (94); vertical stabiliser (95) and rudder (96); wingtip control surfaces (4) or ailerons (8); pitch angle control (30); airfoil profile modifications by deforming leading or trailing edges, actuated by motors or other devices, or by passive means through centrifugal, aerodynamic, or gravitational forces; or by modulation of one or more lifting rotors (12) and thrust-generating rotors (6).

[0065] It may be that the controller controls the altitude of the aircraft by modulating the lift of at least one lifting rotor (12), or by modulating the lift of at least one airfoil shaped wing (9), typically through one or more of, but not limited to, the following methods: wing pitch angle control, aileron or wing tip control, airfoil profile modulation, or through a combination of modulating the lift of both a lifting rotor (12) and an airfoil shaped wing (9).

[0066] It may be that the aircraft can take off and land on water by means of a central float structure which provides buoyancy to the aircraft on water, allowing it to take off and landing vertically from water, as well as manoeuvre itself. The float may be a wing-tip mounted structure which is used to provide buoyancy. This has the potential advantage of reducing likelihood of the aircraft tipping over due to imbalance. The float structure could also be replaced by hydrofoils or another device which provides hydrodynamic lift upon rotation of the airfoil shaped wings, for the purpose of raising the aircraft out of the water to enable vertical take-off.

[0067] It may be that some parts of the aircraft are not transitioning into a spinning mode when the rotatable body is rotating about its axis. The non-spinning parts could either be decoupled from the spinning part of the fuselage by means of a bearing or by an active control method such as a hydraulic or servo motor or other means which is linked to a control unit which takes an input from a sensor which used magnetics or acceleration or another type for control. The non-spinning components could be limited to a small subset of the parts of the aircraft including but not limited to an undercarriage, lifting device, camera, radar, or cargo compartment. It is also conceivable that a substantial portion of the aircraft including but not limited to the power source and fuel system are located in the non-spinning section of the aircraft and power and signals are transmitted through the interface. The aircraft may comprise a non-spinning lower section.

[0068] The aircraft, with its unique combination of rotorcraft and fixed-wing capabilities, may be adapted for a variety of demanding applications, including but not limited to firefighting, crop spraying, heavy-lift cargo, crew or passenger transport, surveying, and search and rescue operations.

[0069] In firefighting, the aircraft’s VTOL capabilities and efficient operation in its spinning flight mode enable it to pick up large quantities of water or fire retardant and deploy them in remote or inaccessible areas.

[0070] The non-spinning lower section may ultimately be adapted to house a crew and passenger compartment.

[0071] In crop spraying, the aircraft’s ability to modulate lift and maintain controlled, low- altitude flight over fields enables highly efficient dispersal of significant amounts of agent. The more uniform airflow of the large spinning rotor might benefit equal dispersion of the agent which could be dispersed from the central section of the aircraft or from the lift generation wing section (9).

[0072] For heavy-lift cargo, the non-spinning lower section could be utilised for large and heavy cargo which could be wiched up during flight.

[0073] Multiple numbers and combinations of winged surfaces and thrust generating rotors could be used to achieve the aim of this invention. In the simplest case, the thrust rotors are mounted onto the winged structures and change their thrust direction when the wing is rotated thus being able to produce purely vertical take off thrust in the non spinning mode and spinning thrust when the wings are tilted towards the horizontal orientation.

[0074] It may be that some or all of the lift generating propellers are mounted onto the fuselage. As a minimum only one winged lifting surface is required, with the aircraft's mass arranged so that the centre of gravity is offset or located to one side or outside of the winged lifting surface. One or more counterbalance devices may be used to improve stability.

[0075] Multiple wing sections may be arranged around the circumference of the central fuselage, these may be arranged in a uniform or non uniform pattern in one or more planes. Multiple lifting or thrust generating rotors may be arranged along the length of the winged section, these may be of equal design or of different designs optimised for the different tangential velocities along the wing during the spinning mode of operation. This could include a propeller or turbine optimised for high forward velocities at the tip of the winged section and a lifting rotor optimised for high static lift towards the root of the winged section.

[0076] The aircraft maybe configured (for example, the controller may be programmed) to operate in one or another mode during a failure case.

[0077] It may be that in the case of a failure of the vertical lifting rotors, the aircraft can be put into its spinning operation by the thrust generating devices mounted on the wing, thereby producing lift from the wing surface.

[0078] It may be that in the case of a failure of the thrust generating devices which keep the aircraft in its spinning mode, the aircraft can be controlled solely by the vertical lifting rotors.

[0079] It may be that in the case of a failure of all thrust generating devices and all lifting rotors, the aircraft can be put into an autorotation mode by pitching the wing section to a negative angle as is typical of the autorotation mode of a helicopter. It is expected that the high rotational inertia of the winged section will allow for the aircraft to substantially reduce its descent speed before touch down by pitching into a positive angle of attack.

[0080] It may be that in the case of a limited power failure, it might further be possible to enable a spinning autorotation mode by pitching the wing to a negative angle of attack and using the limited remaining thrust or torque from one or more of the lifting rotors or thrust generating rotors to put the aircraft into a spin thereby enabling the autorotation mode.

[0081] In another aspect of the invention there is provided an aircraft featuring at least one lifting rotor (12), one or more lifting airfoil-shaped wings (9), arranged around the circumference of the main fuselage (14) on one or more horizontal planes; at least one thrust-generating device (6) to spin the aircraft, characterised in that the aircraft can be operated in at least three modes, a first mode whereby the lifting rotor (12) or rotors are used for vertical take-off and landing and attitude control in the typical mode of operation found in rotorcraft or multi-rotorcraft, a second mode in which the aircraft operates by spinning around its centre of mass thereby creating all or some of the required lift force to take off or stay airborne from the one or more airfoil shaped wings (9), and a third mode of operation using one or more airfoil shaped wings (9) to provide some or all of the lift force and one or more thrust generating devices (6), or one or more lifting rotors (12), or a combination of each, for directional flight propulsion in the typical mode of operation of an aeroplane.

[0082] The invention extends in a fifth aspect to a method of operating an aircraft, the aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, the method comprising changing the orientation of the aircraft during flight by modulating the aerodynamic lift of at least one airfoil-shaped wing (9) in phased relationship with revolutions of the rotatable body. The aircraft may be an aircraft according to the first aspect.

[0083] The invention extends in a sixth aspect to a method of operating an aircraft, the aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, the method comprising changing the orientation of the aircraft during flight by modulating the lift of at least one lifting rotor (12). The aircraft may be an aircraft according to the second aspect. The aircraft may be an aircraft according to the first and second aspect.

[0084] The invention extends in a seventh aspect to a method of controlling an aircraft, the aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, the method comprising operating the aircraft in at least:

[0085] (i) a first mode in which the at least one lifting rotor (12) is used for vertical take-off or landing and attitude control; (ii) a second mode in which the rotatable body is spun around the axis of rotation and the one or more lifting airfoil-shaped wings (9) create some or all of the lift required to take off or stay airborne; and

[0086] (iii) a third mode in which the one or more lifting airfoil-shaped wings (9) create some or all of the lift required to take off or stay airborne, and wherein the one or more thrust generating devices (6) and / or at least one lifting rotor (12) provide directional flight propulsion.

[0087] The aircraft may be an aircraft according to the third aspect.

[0088] In an eighth aspect there is provided a method of operating an aircraft, the aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, the method comprising independently controlling the at least one lifting rotor (12) and the at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, typically wherein the at least one thrust-generating device (6) is a rotor (6) mounted to a lifting airfoil-shaped wing (9). The aircraft may be an aircraft according to the fourth aspect.

[0089] Features described above are optional features of each aspect of the invention. The aspects may be combined with each other.

[0090] Description of the Drawings

[0091] An example embodiment of the present invention will now be illustrated with reference to the following Figures in which:

[0092] Figure 1 is a plan view of an aircraft with two winged surfaces and four lift rotors;

[0093] Figure 2 is a plan view of an alternative aircraft with two winged surfaces and four lift rotors;

[0094] Figure 3 is a plan view of an aircraft with tiltable wings;

[0095] Figure 4 is a top view of the aircraft of Figure 3;

[0096] Figure 5a is a plan view of an aircraft with a lifting device; Figure 5b is a plan view of an aircraft with an undercarriage solidly mounted onto the main fuselage;

[0097] Figure 6 shows a plan view of an aircraft like that of Figure 3 but with 4 airfoil shaped wings;

[0098] Figure 7a shows a plan view of an aircraft like Figure 5a but with a central float structure;

[0099] Figure 7b shows a plan view of an aircraft like Figure 7a but with wing-tip mounted float structures;

[0100] Figure 8a shows a side view of an airfoil shaped wing with leading edge mounted thrust generating motor and rotor with an actuator;

[0101] Figure 8b shows a similar arrangement but where the wing structure angle is fixed;

[0102] Figure 9a is a plan view of an aircraft in which the winged section has a symmetric profile;

[0103] Figure 9b is a cross-section of an airfoil;

[0104] Figure 10a is a plan view of an aircraft similar to Figure 3 showing azimuthal angle of the rotating body and wings; and

[0105] Figure 10b is a graph of lift variation of a winged section with azimuthal angle for two wings with side directional or front directional flight.

[0106] Detailed Description of an Example Embodiment

[0107] Figure 1 shows one possible implementation of the proposed invention. The arrangement in Figure 1 consists of two winged lifting surfaces (9) and four lifting rotors (12). A different number of winged surfaces and lift rotors may be used, following a similar operational principle.

[0108] The winged structures (9) are equipped with aerodynamic control surfaces to modulate lift either in phased relationship with rotation of the rotatable body or overall, similar to a helicopter’s cyclic or pitch control. To achieve this, ailerons (8) and / or wingtip control surfaces (4) may be integrated into the winged surface, allowing lift modulation during spinning mode to stabilise the aircraft. Other means, such as wing chord profile modulation, full wing pitch control, or alternative methods for adjusting aerodynamic lift, may also be considered. In the implementation shown in Figure 1 , four lift rotors (12) are mounted to the central fuselage (14) via four outrigger elements (10).

[0109] In the first mode of operation, the aircraft functions like a quadcopter, with the four lift rotors (12) lifting it off the ground and controlling its flight.

[0110] In the second mode of operation, lift is generated by activating the thrust motors (5) to drive the thrust propeller (6), causing the aircraft to spin around its central axis. In this embodiment, the whole aircraft functions as the rotatable body. The proposed aircraft can operate in either mode or a combination of both simultaneously. Any of these modes, or a combination, can be used during various phases of flight, such as takeoff, hover, cruise, or landing.

[0111] During transitions, different modes are possible. The spinning mode can be initiated by adjusting the speeds and directions of the lift rotors (12), similar to quadcopter yaw control, or it can be initiated solely through the thrust rotors (6).

[0112] The position of the aircraft in spinning mode can be controlled through the lift rotors (12) or the aerodynamic control surfaces (4) and (8) on the winged sections (9). A combination of control from both the lift surfaces and the lift rotors (12) may also be used to control the aircraft during flight.

[0113] In this example, the aircraft can be controlled solely by the aerodynamic control surfaces on the winged sections or by the lift rotors (12). This mode could be incorporated to reduce cost and complexity or to serve as a backup control method if one of the systems fails or is partially disabled.

[0114] In the example shown in Figure 1 , the lift rotors (12) are powered by hydraulic motors (11) connected to a central pump unit (1), which is driven by a central engine or another power source (2). The thrust-generating rotors (6) are powered by hydraulic motors (5), also connected to the central pump unit (1). The central pump unit may be a digital displacement pump, allowing simultaneous control of multiple loads. Alternatively, the lift rotors (12) and thrust-generating rotors (6) could be powered by other means, such as electric motors, directly coupled combustion engines, or jet engines. In the depicted setup, the connection between the central pump unit (1) and the thrustgenerating rotors (5) and (12) is made via hydraulic lines (7). However, other power transmission methods, such as direct drive shafts, chains, or belts, could also be used.

[0115] The example of Figure 1 includes two winged surfaces and four lift rotors, with the lift rotors (12) positioned on either side of the winged surfaces. Other configurations, such as four winged surfaces with four lift rotors (12), or other combinations, may also be considered.

[0116] Figure 2 shows a similar arrangement to Figure 1. However, in the example of Figure

[0117] 2, the lifting rotors (12) are not connected directly to the central fuselage (14). Instead, they are mounted onto outriggers (21), which are attached to the wing section (9). This differs from the configuration in Figure 1 , where the lifting rotors (12) are positioned on outrigger elements (10) that are connected directly to the central fuselage (14). Again, the whole aircraft functions as the rotatable body.

[0118] Figure 3 shows a similar arrangement to Figure 1. However, in the example of Figure

[0119] 3, the airfoil shaped wings (9) can be tilted by using a pitch control device (30). In this arrangement, the thrust generating rotors (6) provide the vertical lift for take off when the wings (9) are in vertical orientation and when the wings are at an angle less than 90 degrees from the horizontal plane they provide the function of producing a force which rotates the wing (9) about its centre of rotation.

[0120] Figure 4 shows a top view of the same arrangement shown in Figure 3.

[0121] Figure 5a shows an example aircraft similar to the one depicted in Figure 4, but with an additional feature: a lifting device (51). The lifting device (51) is connected to a landing gear or undercarriage (55), which is linked to the main fuselage of the aircraft via an active control mechanism. This active control mechanism consists of a drive unit (52) and a bearing and / or gear arrangement (53). The control unit (52) can be set to keep the undercarriage in a non-spinning mode while the upper section of the aircraft operates in spinning mode. The upper section thereby functions as the rotatable body. This capability offers operational benefits, such as allowing the upper section to spin while the aircraft lands safely on the stationary undercarriage (55). This configuration makes it possible to land or take off while the aircraft is spinning. Additionally, it allows for underslung loads to be attached to the lifting hook (51) without the risk of the load spinning or the lifting rope becoming tangled. The control mechanism (52) and connecting mechanism (53) can be various types, including electric motors, hydraulic motors, servo motors, or even passive systems with low-friction bearings and other means to prevent the undercarriage (55) from spinning.

[0122] Figure 5b shows the same aircraft architecture as depicted in Figure 5A. However, unlike in Figure 5A, the example of Figure 5b has an undercarriage which is solidly mounted onto the main fuselage, meaning it will spin or move together with the aircraft. The hook unit (51) is connected via the bearing and control units (53) and (52). These units can be controlled in such a way that, even when the aircraft enters its spinning mode, the hook remains stationary and does not rotate with the aircraft. The control units (52) and (53) can either be passive, using a bearing system, or an active control system. Additionally, it is possible to control the rotational position of the hook unit (51) to prevent the lift rope from becoming tangled in the event that the underslung load starts spinning due to other aerodynamic forces.

[0123] Figure 6 shows an example which has a similar arrangement to Figure 3 from a top view but with 4 airfoil shaped wings (9), with each wing having the lifting rotor (6) as well as an additional lifting rotor (61).

[0124] Figure 7a shows an example which has a similar arrangement to Figure 5b, however the landing gear skid is replaced by a central float structure (71) which provides buoyancy to the aircraft on water, allowing it to take off and landing vertically from water, as well as manoeuvre itself. This centralised float structure (71) is one example of a float structure which may be used, in combination with or replaced by a float structure which may not be attached to the central fuselage (14). The float (71) could be rigidly mounted to the fuselage (14) or decoupled through a passive or active bearing element.

[0125] Figure 7b shows an example which has a similar arrangement to Figure 7a but instead of a centralised float structure (71), wing-tip mounted float structures are used to provide buoyancy. This has the potential advantage of reducing likelihood of the aircraft tipping over due to imbalance. The float structure could also be replaced by hydrofoils or another device which provides hydrodynamic lift upon rotation of the airfoil shaped wings (9), for the purpose of raising the aircraft out of the water to enable vertical take-off.

[0126] Figure 8a shows a side view of the airfoil shaped wing (9) with a leading edge mounted thrust generating motor (5) and rotor (6) with an actuator (81), which may be hydraulic in type, to tilt the wing structure thereby changing its angle of attack with respect to the resultant direction of the airflow as in the typical mode of operation in tilt wing aircraft. By changing the tilt angle of the wing structure (9) it simultaneously changes the thrust vector of the thrust generating motor (5) and rotor (6) thus modulating the component of force produced in the horizontal and vertical axes.

[0127] Figure 8b shows a similar arrangement to Figure 8a, however the wing structure angle is fixed at a set angle with the thrust generating motor (5) and rotor (6) on a separate tilt mechanism (82) thus modulating the component of force produced in the horizontal and vertical axes, as in the typical mode of operation of a tilt rotor aircraft.

[0128] Figure 9a presents an additional example. In this example, the winged section (9) features a symmetric profile, allowing it to generate thrust in both directions depending on the angle of attack. This capability can be further enhanced by adding aerodynamic control surfaces at the tip or tail, or other mechanisms to modify the profile of the winged section. This arrangement enables the aircraft to operate in three distinct modes;

[0129] First mode: Vertical take-off - In this mode, one or more thrust-generating propellers (6) are oriented upward, enabling vertical lift.

[0130] Second mode: Spinning flight - In this mode, the winged sections (9) rotate, with the profile and thrust-generating propellers oriented in opposing directions, causing the aircraft to spin.

[0131] Third mode: Horizontal flight - In this mode, the two winged sections (9) and some or all of the thrust propellers (6) are directed in the same direction, allowing the aircraft to transition into horizontal flight. In the third mode, the aircraft flies like an aeroplane, using the winged sections to generate lift. In the third mode, the rotatable body does not rotate. The winged sections are translated generally horizontally as per normal fixed wing aeroplane operation.

[0132] The arrangement shown in Figure 9 illustrates two thrust propellers (6), but a different number of thrust propellers may also be used. The thrust propellers may be positioned along the nose of the winged section (9) or on either side of the winged section (9) using mounting structures to provide greater stability during vertical flight. Additionally, it is conceivable that some of the thrust rotors (6) could be mounted on the winged section (9), while others may be attached to the main fuselage (14) via a mounting frame structure.

[0133] The ability to transition into forward flight mode allows the aircraft to achieve higher cruising speeds and cover longer distances. With both winged sections (9) aligned in the same direction during horizontal flight, the aircraft can be designed as a flying wing, utilising control surfaces installed on the winged section (9) to stabilise the aircraft. It is also conceivable to add additional control surfaces to the main fuselage (14) or the winged sections (9). These may include, but are not limited to, a horizontal stabiliser (93) with an elevator (94), and a vertical stabiliser (95) with a rudder (96), which could be arranged either in front of or behind the main winged sections (9).

[0134] Figure 9b shows a possible implementation of an airfoil that can be symmetric or morphed into a curved airfoil in both concave or convex direction by actuation of the control surfaces (91) and (92) or by passive means.

[0135] Figure 10a shows an example according to Figure 3, but this image illustrates the proposed aircraft with a focus on the rotational dynamics of the winged sections (9). The diagram shows the rotatable body in its spinning mode, with specific angles of rotation marked around the azimuth. As discussed, the lift of the winged sections (9) is varied in phased relationship with the rotation of the rotatable body to control the orientation of the aircraft. The winged sections (9) are highlighted along with the aileron control surfaces (8), with arrows indicating the direction of rotation. Key angles such as 0°, 90°, 180°, and 270° are marked around the circumference of the rotational plane. It also illustrates how the modulation of aerodynamic lift varies at different segments of the rotation, enabling the aircraft to adjust its attitude and achieve controlled motion in various directions. Other methods of modulating the lift produced by the wing (9) including but not limited to wing pitch control, wing tip control, airfoil profile modulation or other means also work on the same principle of synchronising their operation with the phase of rotation.

[0136] Figure 10b presents a graph showing multiple sinusoidal curves, each representing the lift variation of a winged section (9) relative to its angle of rotation. The curves for wing 1 and the curves for wing 2 which are phase shifted by 180 degrees, represent the lift variation of the second winged section. To change the direction of orientation of the aircraft, the phase of sinusoidal curves for wing 1 and wing 2 are shifted together. The x-axis indicates the angle of rotation, ranging from 0° to 360°, while the y-axis represents a normalised value of the lift generated. The graph demonstrates how the lift of each winged section is modulated out of phase to achieve balanced control of the aircraft during its spinning mode.

[0137] Throughout the description and claims of this specification, the words “comprise” and “contain” and variations of them mean “including but not limited to”, and they are not intended to and do not exclude other components, integers, or steps. Throughout the description and claims of this specification, the singular encompasses the plural unless the context otherwise requires. In particular, where the indefinite article is used, the specification is to be understood as contemplating plurality as well as singularity, unless the context requires otherwise.

[0138] Features, integers, characteristics, or groups described in conjunction with a particular aspect, embodiment, or example of the invention are to be understood to be applicable to any other aspect, embodiment or example described herein unless incompatible therewith. All of the features disclosed in this specification (including any accompanying claims, abstract and drawings), and / or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at least some of such features and / or steps are mutually exclusive. The invention is not restricted to the details of any foregoing embodiments. The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims, abstract and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.

Claims

Claims1. An aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, and a controller configured to change the orientation of the aircraft during flight by modulating the aerodynamic lift of at least one airfoil-shaped wing (9) in phased relationship with revolutions of the rotatable body.

2. An aircraft according to claim 1 , wherein the controller is configured to modulate the aerodynamic lift of at least one airfoil-shaped wing (9) by controlling one or more of: at least one aileron (8), at least one wing tip control surface (4), a wing pitch modulator (30) or wing profile modulator in phased relationship with revolutions of the rotatable body.

3. An aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, and a controller configured to change the orientation of the aircraft during flight by modulating the lift of at least one lifting rotor (12).

4. An aircraft according to claim 3, wherein the lifting rotors (12) are fixedly coupled to and rotate with the rotatable body and the controller is configured to change the orientation of the aircraft during flight by modulating the lift of at least one lifting rotor (12) in phased relationship with revolutions of the rotatable body.

5. An aircraft according to claim 3 or claim 4, wherein the controller is also configured to change the orientation of the aircraft during flight by modulating the aerodynamic lift of at least one airfoil-shaped wing (9) in phased relationship with revolutions of the rotatable body.

6. An aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, and a controller configured to operate the aircraft in at least:(iv) a first mode in which the at least one lifting rotor (12) is used for vertical take-off or landing and attitude control;(v) a second mode in which the rotatable body is spun around the axis of rotation and the one or more lifting airfoil-shaped wings (9) create some or all of the lift required to take off or stay airborne; and(vi) a third mode in which the one or more lifting airfoil-shaped wings (9) create some or all of the lift required to take off or stay airborne, and wherein the one or more thrust generating devices (6) and / or at least one lifting rotor (12) provide directional flight propulsion.

7. An aircraft according to any one preceding claim, wherein all or some of the lifting rotors (12) and thrust-generating devices (6) are driven by hydraulic motors (11) which may be connected to one or more common or separate variable flow displacement pumps (1), which may be synthetically commutated, and one or more common power units (2), which may be combustion engines, through hydrostatic transmission lines (7), with the power unit (2) located in the central fuselage (14).

8. An aircraft according to any one preceding claim, wherein at least one airfoilshaped wing (9), or one or more counterweights for balance, or a combination of both, are arranged around the circumference of the main fuselage (14) on one or more horizontal planes.

9. An aircraft according to any one preceding claim, wherein one or more of the lifting devices (12) and one or more of the thrust-generating devices (6) spinning the aircraft about its centre of rotation are the same devices, characterised in that said devices transition from vertical to horizontal thrust orientation during mode changes by means of tilting the airfoil shaped wing (9) or by tilting the lifting and thrust generating rotor (12) and (6) or by another means.

10. An aircraft according to any one preceding claim, whereby at least one lifting rotor (12) is mounted on the airfoil-shaped wing (9) or to the wing by an outrigger (21) or attached to the fuselage (14) via a boom arm (10) or other device, characterised in that said lifting rotor (12), boom arm (10), outrigger (21) or airfoil-shaped wing (9) is foldable or extend to change the size of the aircraft for transport.

11. An aircraft according to any one preceding claim, wherein the aircraft has a central fuselage section to house individual components, characterised in that the central fuselage (14) and any lifting rotors (12) attached to it are non-spinning relative to the rotation of the rotatable body (and thereby one or more airfoil-shaped wings (9)) by use of a bearing (53) or other device controlled in an active or passive manner.

12. An aircraft according to any one preceding claim, wherein at least one lifting rotor (12), or at least one airfoil-shaped wing (9) or, a combination of both, operates at a fixed rotational speed and modulates its lift using collective and cyclic pitch control mechanisms.

13. An aircraft according to claim 12, where there is only one central lifting rotor (12) with active pitch control located in line with the central fuselage (14).

14. An aircraft according to any one preceding claim, wherein at least two lifting rotors (12) or at least two airfoil-shaped wings (9), or a combination thereof, rotate in a contra-rotating configuration about a common rotational axis, or with the rotational axes offset by a distance.

15. An aircraft according to any one preceding claim, whereby the aircraft can autorotate for a safe landing in the event of failure of one or more power units by at least one of but not limited to the following means, pitch angle control; airfoil profile modifications by deforming leading or trailing edges of by active means, actuated by motors or other devices, or by passive means through centrifugal, aerodynamic, or gravitational forces, typically under the control of the controller.

16. An aircraft according to any one preceding claim, wherein the aircraft is operable underwater with the power unit (2) connected to an underwater breathing apparatus, compressed air tank, or other device, further characterised by using one or more underwater thrust-generating devices, which may be the same or a separate devices to one or more of the lifting rotors (12) or one or more of the thrust-generating devices (6), or a combination thereof.

17. An aircraft according to any one preceding claim, wherein the winged section (9) can be pitched to point the thrust generating rotors (6) in opposing direction thereby placing the aircraft into a spinning mode or can be kept in the same orientation with the ability of the aircraft to transition into a forward flight mode, with the airfoil sections being able to produce lifting thrust in both directions depending on the forward flight mode or the spinning mode.

18. An aircraft according to claim 17, wherein the winged profile (9) is of symmetric geometry in order to achieve thrust in both directions depending on the angle of attack, or is of a type which can morph into a non symmetric profile by means including but not limited to a wing tip control surface (4), a wing tail control surface (8) or other means to change its wing profile.

19. An aircraft according to claim 17, wherein the aircraft has additional features to improve stability and flight control in forward flight which could be but not limited to a horizontal stabiliser and elevator control surface and a vertical stabiliser and rudder control surface.

20. An aircraft according to any one preceding claim, wherein a cargo load is connected to the aircraft rigidly or non-rigidly in an underslung manner or other method, characterised in that the cargo load can be winched up and down using a motor or other device, and the position of the underslung cargo load can be actively controlled by means of a mechanical actuator, thruster, or other device, and the cargo load may be non-spinning relative to the rotating airfoil-shaped wing (9) by use of an active or passive device of bearing (53) or other type.

21. An aircraft according to any one preceding claim, wherein one or more buoyancy devices in the form of floats (71 , 72) are attached to the central fuselage (14) or wings (9) allowing the aircraft to take off, land, and manoeuvre on water, with one or more hydrofoils used to facilitate transition into the spinning mode on water, and at least one flotation device which may be mounted at the tip of a wing to improve balance.

22. An aircraft according to any one preceding claim, wherein the aircraft transitions directly into the spinning mode on the ground by rotating about a landinggear that does not rotate, using a bearing (53) or other device, alternatively the landing gear rotates with the aircraft on the ground by use of wheels.

23. An aircraft according to any one preceding claim, wherein the attitude control and stability of the aircraft in the second (spinning) mode of operation requires cyclic modulation of lift in phased relationship with revolutions of the rotatable body, which may be achieved by one or more of the following means, wingtip control surfaces (4) or ailerons (8); pitch angle control (30); airfoil profile modifications by deforming leading or trailing edges, actuated by motors or other devices, or by passive means through centrifugal, aerodynamic, or gravitational forces; or by modulation of one or more lifting rotors (12) and thrust-generating rotors (6).

24. An aircraft according to any one preceding claim, wherein the attitude control and stability of the aircraft in the third mode of operation (as an airplane) is achieved by one or more of the following means, horizontal stabiliser (93) and elevator (94); vertical stabiliser (95) and rudder (96); wingtip control surfaces (4) or ailerons (8); pitch angle control (30); airfoil profile modifications by deforming leading or trailing edges, actuated by motors or other devices, or by passive means through centrifugal, aerodynamic, or gravitational forces; or by modulation of one or more lifting rotors (12) and thrust-generating rotors (6).

25. As aircraft according to any one preceding claim, wherein the controller controls the altitude of the aircraft by modulating the lift of at least one lifting rotor (12), or by modulating the lift of at least one airfoil shaped wing (9), typically through one or more of, but not limited to, the following methods: wing pitch angle control, aileron or wing tip control, airfoil profile modulation, or through a combination of modulating the lift of both a lifting rotor (12) and an airfoil shaped wing (9).

26. An aircraft comprising at least one lifting rotor (12), a rotatable body comprising one or more lifting airfoil-shaped wings (9), and at least one thrust-generating device (6) to spin the rotatable body around an axis of rotation, and a controller configured to independently control the at least one lifting rotor (12) and the at least one thrustgenerating device (6) to spin the rotatable body around an axis of rotation, typically wherein the at least one thrust-generating device (6) is a rotor (6) mounted to a lifting airfoil-shaped wing (9).

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