WO2014118299A1

WO2014118299A1 - Aircraft and method for controlling an aircraft for vertical take-off and landing with a win arrangement comprising an extendible lift increasing system

Info

Publication number: WO2014118299A1
Application number: PCT/EP2014/051847
Authority: WO
Inventors: Johannes Reiter
Original assignee: Johannes Reiter
Priority date: 2013-01-31
Filing date: 2014-01-30
Publication date: 2014-08-07
Also published as: GB201301748D0

Abstract

The present invention relates to an aircraft comprising a fuselage (100) comprising a fuselage axis (101), a first wing arrangement (110) and a second wing arrangement (120). The first wing arrangement (110) is mounted to the fuselage (100) such that the first wing arrangement (110) is tiltable around a first rotary wing axis (111) of the first wing arrangement (110) and such that the first wing arrangement (110) is rotatable around the fuselage axis (101). The first wing arrangement (110) is adapted in such a way that, in a fixed-wing flight mode, the first wing arrangement (110) do not rotate around the fuselage axis (101). The first wing arrangement (110) is further adapted in such a way that, in a hover flight mode, the first wing arrangement (110) is tilted around the respective first rotary wing axis (111) with respect to its orientation in the fixed-wing flight mode and that the first wing arrangement (110) rotates around the fuselage axis (101). The aircraft further comprises an extendible lift increasing system which is arranged to the first wing arrangement (110) for selectively amending a lift area of the first wing arrangement (110) in the fixed-wing flight mode and the hover flight mode.

Description

AIRCRAFT AND METHOD FOR CONTROLLING AN AIRCRAFT FOR VERTICAL TAKE-OFF AND

LANDING WITH A WIN ARRANGEMENT COMPRISING AN EXTENDIBLE LIFT INCREASING SYSTEM

FIELD OF THE INVENTION

The present invention relates to an aircraft for vertical take-off and landing with a wing arrangement comprising an extendible lift increasing system and to a method for operating an aircraft for vertical take-off and landing .

BACKGROUND OF THE INVENTION

It is an aim to have aircraft that are able to start and land without a runway for example. Hence, in the past several developments for so called Vertical Take-Off and Landing aircraft (VTOL) have been done. Conventional VTOL- Aircraft need a vertical thrust for generating the vertical lift. Thrust for vertical take-off may be produced by big propellers or jet engines. Propellers may have the disadvantage in travel flight of an aircraft due to a high drag .

An efficient solution for a hover flight capable aircraft is performed by helicopters, using e.g . a big wing area. In a known system, an aircraft comprises an engine for vertical lifting the aircraft (e.g . a propeller) and e.g . a further engine for generating the acceleration of the aircraft in a travel mode up to a desired travelling speed .

In the hover flight mode, the rotating wings or blades of an aircraft (e.g. a helicopter) generate the vertical lift. The rotating wings comprise a chord line, wherein an angle between the chord line and the streaming direction of the air may be called angle of attack. A higher angle of attack generates a higher lift and a lower angle of attack generates a lower lift but also less drag . In order to achieve a higher efficiency of the rotating wings it may be helpful to adjust the angle of attack. Thus, the wings may be tilted around its longitudinal axis.

OBJECT AND SUMMARY OF THE INVENTION

It may be an object of the present invention to provide an efficient aircraft for vertical take-off and landing with proper flight conditions.

This object may be solved by an aircraft for vertical take-off and landing and by a method for operating such an aircraft according to the independent claims.

According to a first aspect of the present invention, an aircraft is presented . The aircraft comprises a fuselage comprising a fuselage axis, a first wing arrangement and a second wing arrangement. The first wing arrangement is mounted to the fuselage such that the first wing arrangement is tiltable around a first rotary wing axis of the first wing arrangement and such that the first wing arrangement is rotatable around the fuselage axis. The first wing arrangement is adapted in such a way that, in a fixed-wing flight mode, the first wing arrangement does not rotate around the fuselage axis. The first wing arrangement is further adapted in such a way that, in a hover flight mode, the first wing arrangement is tilted around the respective first rotary wing axis with respect to its orientation in the fixed-wing flight mode and that the first wing arrangement rotates around the fuselage axis. According to a further aspect of the present invention, a method for controlling the above-described aircraft for vertical take-off and landing is presented . According to the method, the aircraft is converted in a fixed wing flight mode by arranging the first wing arrangement and the fuselage with respect to each other such that the fixed wing flight is enabled . Furthermore, the aircraft is converted in the hover flight mode by tilting the first wing arrangement around the first rotary wing axis and by rotating the first wing arrangement around a fuselage axis for enabling the hover flight. An extendible lift increasing system which is arranged to the first wing arrangement for selectively amending a lift area of the first wing arrangement in the fixed-wing flight mode and the hover flight mode may be extended or pulled in.

The aircraft may further comprise a second wing arrangement which is mounted to the fuselage spaced apart from the first wing arrangement along the fuselage axis.

In an exemplary embodiment, additionally the second wing arrangement is adapted in such a way that, in a fixed-wing flight mode, the second wing arrangement does not rotate around the fuselage axis, wherein the second wing arrangement is further adapted in such a way that, in a hover flight mode, the second wing arrangement is tilted around the respective first rotary wing axis with respect to its orientation in the fixed-wing flight mode and that the second wing arrangement rotates around the fuselage axis. The first wing arrangement may rotate around the fuselage axis around a first direction. The second wing arrangement may rotate around the fuselage axis around a second direction. The second direction may be the same or an opposite direction with respect to the first direction.

The respective (first and/or second) wing arrangements comprise respective rotary wing axes, wherein the respective rotary wing axes are the respective axes around which the respective wing arrangement is tiltable with respect to the fuselage for achieving the fixed wing flight mode or the hover flight mode. At least the first wing arrangement is tiltable around the rotary wing axis. In an exemplary embodiment, the second wing arrangement may also be tiltable around the second rotary wing axis, such that also the second wing

arrangement is rotatable around the fuselage axis in the hover flight mode. In particular, the second wing arrangement may rotate in opposite direction around the fuselage axis in comparison to the first wing arrangement. By this configuration, in hover flight mode, due to the spaced positioning of the second wing arrangement in relation to the first wing arrangement, a stabilizing gyro spin is achieved, making the rotor in flight stable. Usually the second wing arrangement is not rotatable around the fuselage axis due to the installation of sensitive equipment in the fuselage. Alternatively, still a configuration can be made with all parts rotating or similar. Therefore the equipment has to be built up rotation resistant.

The first wing arrangement or the second wing arrangement can be under or downside on the fuselage in the hover flight mode if the fuselage stands with its tail on the ground (rotating wing arrangement is near the ground and therefore the overall configuration is less affected by sidewind). Also small wheels can be positioned on wing tips of respective wing arrangements, so that the rotor can then be used as a landing gear in the same time.

A longitudinal wing axis of a respective wing arrangement may be defined by the run of a respective main wing spar or by a respective bolt that connects for example a respective wing root of the respective wing arrangement with the fuselage. The respective wing arrangement is mounted by its wing root(s) to the fuselage, wherein at an opposite end of the respective wing

arrangement with respect to the respective wing root a wing tip is defined, which is a free end of the respective wing arrangement. The longitudinal wing axis may be non-parallel to the leading and/or trailing edge. Between the longitudinal wing axis and the leading edge and trailing edge an angle in the range between 0° to 90° from the leading edge and trailing edge may exist.

A chord line of the wing arrangement and the wings, respectively, refers to an imaginary straight line connecting the leading edge and the trailing edge within a cross-section of an airfoil. The chord length is the distance between the trailing edge and the leading edge. The longitudinal wing axis may be defined as an axis running along the wing arrangement through a so called quarter-chord line. Hence, usually the longitudinal wing axis crosses the chord lines of respective cross sections of the wing arrangement at a distance of one quarter of the total chord line length from a leading edge of the wing arrangement and its respective wings, respectively.

The respective rotary wing axis of a respective wing arrangement may be parallel e.g . with a leading edge or a trailing edge of the respective wing arrangement. The rotary wing axis may be parallel or non-parallel with the longitudinal wing axis. The rotary wing axis may be defined by the run of a respective main wing spar or by a respective bolt that connects for example a respective wing root of the respective wing arrangement with the fuselage. In an exemplary embodiment, the wing arrangement may comprise no wing swept with respect to the fuselage axis, so that the rotary axis may be perpendicular to the fuselage axis. In an alternative exemplary embodiment, the wing arrangement may comprise a wing swept with respect to the fuselage axis, so that the rotary axis may comprise an angle with respect to the fuselage axis that differs to 90°.

If the rotary wing axis differs from the longitudinal wing axis, this may have an advantage for the COG ("Center of Gravity") of the overall configuration. It is possible to keep the rotary wing axis straight 90° away from the fuselage axis even if the longitudinal wing axis is not aligned perpendicular to the fuselage axis and the respective wing arrangements comprise a wing swept. Alternatively, the rotary wing axis is parallel to the longitudinal wing axis, even if the respective wing arrangements comprise a wing swept. Hence, the wing arrangement forms with the fuselage a "Y"- shape, wherein during tilting of the wing arrangement around the rotary wing axis the "Y"- Shape is still preserved . The rotary wing axis of the respective wing arrangements can be hugely different to the longitudinal wing axis of the respective wing

arrangements. Thus, having the rotary axis of the respective rotating wing arrangement for example perpendicular to the fuselage axis in the hover flight mode, the wing configuration looks like a "T" in a side view (with 0° angle of attack from the rotor relatively to the static air). The wings are straight in side view, respectively. If the respective wing arrangement is tilted from the hover flight mode to the fixed wing flight mode around the rotary wing axis, a wing swept may result and a differing angle between the longitudinal wing axis and the rotary wing axis of the respective wing arrangement is formed. Each of the respective wing arrangements may comprise one, two or a plurality of wings. Each wing may comprise an aerodynamical wing profile comprising a respective leading edge where the air impinges and a respective trailing edge from which the air streams away from the wing. According to the approach of the present invention, the first wing arrangement comprises an extendible lift increasing system, such as extendible slats or flaps, which is arranged to the first wing arrangement for selectively amending the lift area of the first wing arrangement in the fixed wing flight mode and the hover flight mode.

For example, in a fixed wing flight mode, in particular during starting or landing of the aircraft, it may be beneficial for the flight characteristics to increase the lift area of the wing arrangement. Hence, the extendible lift increasing system may extend additional lift areas, such as flaps or slats. For example, in the hover flight mode, it may be beneficial to reduce the lift area of the wing arrangement. Hence, the lift increasing system may pull in the additional lift area, such as the slats and the flaps, in order to reduce the overall lift area of the wing arrangement.

Hence, by the approach of the present invention, an aircraft which is able to fly in a fixed wing mode and in a hover flight mode is presented, wherein the flight characteristics may be amendable by the extendible lift increasing system. Hence, the lift area of the first wing arrangement may be adapted to the respective flight mode. The extendible lift increasing system may comprise an extendible flap arrangement which is arranged at the trailing edge of the first wing

arrangement. Additionally or alternatively, the extendible lift increasing system comprises an extendible slat which is arranged at a leading edge of the first wing arrangement. The extendible lift increasing system, i.e. its flaps or slats, increases the camber or curvature of the wing arrangement and raises the maximum lift coefficient. This allows the aircraft to generate more lift at a lower speed, reducing the stalling speed of the aircraft or the minimum speed at which the aircraft will maintain flight. Extending flaps increases drag which can be beneficial during approach and landing because it slows the aircraft. A further effect of flap deployment is a decrease in aircraft pitch angle which improves the pilot's view of the runway over the nose of the aircraft during landing . The slats or flaps may be designed as plain flaps or slats, slotted flaps or slats and/or Fowler flaps or slats. Flaps used on the leading edge of the wing arrangement are called Krueger flaps or slats.

The first wing arrangement is located closer to a nose of the fuselage along the fuselage axis than the second wing arrangement. That can be inverted, for example, as well. The fuselage may comprise a provision for supplying sensors, such as cameras or measurement equipment for physical parameters (e.g. temperature, pressure). Furthermore, a cockpit for a pilot of the aircraft may be installed in the fuselage. Also control devices are installed in the fuselage. Specifically, remote controlled devices for remotely controlling the aircraft are installed in the fuselage for enabling an unmanned flight of the aircraft.

The fuselage describes a main body of the aircraft, wherein in general the centre of gravity of the aircraft is located inside the area of the fuselage. The fuselage may be in one exemplary embodiment of the present invention a small body to which the respective first and second wing arrangements are rotatably mounted, so that the aircraft may be defined as a so-called flying wing aircraft. In particular, the fuselage may be a section of the wing arrangements and the fuselage may comprise a length equal to the chord line (e.g. a width) of a respective wing of a respective wing arrangement.

Alternatively, the fuselage comprises a length that is longer than e.g . the chord line (e.g . the width) of the respective wing of the respective wing arrangement. The fuselage comprises a nose and a tail section.

The fuselage axis is the rotary axis (but that is not limited to it) around which the respective wing arrangement may rotate, in particular around the fuselage. A swash plate mechanism and/or mechatronic/electronics control assemblies can also be included. The fuselage axis may be in an exemplary embodiment the longitudinal fuselage symmetry axis of the fuselage. In an exemplary embodiment, the fuselage axis may comprise an angle with respect to the longitudinal fuselage symmetry axis and may thus run non-parallel to the longitudinal fuselage symmetry axis. Alternatively, it also could possibly run in any other axis. Alternatively, it can be changeable during flight by controls in order to influence flight direction in hover flight mode.

The aircraft according to the present invention may be a manned aircraft or an unmanned aerial vehicle (UAV) or remotely piloted aerial vehicle (RPAV). The aircraft may be e.g . a drone that comprises for example a wingspan of approximately 1 m to 4 m (meter) with a weight of approximately 4 kg to 6 kg (kilograms). In another exemplary embodiment, the aircraft according to the present invention may have a weight up to 40 Tons and beyond . The span width of the first wing arrangement of such a heavy configuration may be longer than 25 meter, in particular longer than 30 meter.

In the fixed-wing flight mode, the first and second wing arrangements are fixed to the fuselage without having a relative motion between the wing arrangements and the fuselage, so that by a forward motion of the aircraft trough the air lift is generated by the wing arrangements. Therewith also the wings can be rotated parallel so that the fixed wing aircraft can make climbs while the fuselage stays fixed in its relative position to its surrounding area.

In the hover flight mode, the first wing arrangement (and in another exemplary embodiment also the second wing arrangement) rotates around the fuselage axis or any similar axis, so that due to the rotation of the first wing arrangement through the air a lift is generated even without a relative movement of the aircraft through the air. Hence, by rotating the first wing arrangement through the air, a hover flight mode is achievable, e.g . such as a helicopter's. Moreover, if the first wing arrangement rotates in the hover flight mode around the fuselage axis, a stabilizing moment (e.g . a gyroscopic moment, i.e. a conservation of angular momentum) for stabilizing the aircraft is generated. The respective wing arrangements may be connected to the fuselage such that the wing arrangements are not rotatable relative to the fuselage. Hence, in the hover flight mode, both, the respective wing arrangements and the fuselage may rotate around the fuselage axis for generating lift. In an alternative embodiment, the respective wing arrangements are mounted to the fuselage such that the first wing arrangements rotate around the fuselage axis relatively to the fuselage, so that in the hover flight mode the wing arrangement may rotate for generating lift and the fuselage (and e.g . the second wing arrangement) may not rotate around the fuselage axis. Moreover, if the first wing arrangement rotates in the hover flight mode, a stabilizing moment (e.g. a gyroscopic moment, i.e. a conservation of angular

momentum) for stabilizing the aircraft is generated. And due to the fact that the fuselage is not rotating, the fuselage can be designed in an out- centered (excentered) with weights or payloads of any kind. The rotor axis could be controllably changeable. That makes the configuration even more stable while the fuselage does not need to be centered (money saving due to cheaper build up cost).

Hence, by the present invention, a vertical take-off and landing aircraft is presented which combines the concept of a fixed-wing flight mode aircraft and a hover flight mode aircraft. Hence, both advantages of each flight mode may be combined. For example, a fixed-wing flight aircraft is more efficient during the cruise flight, i.e. when the aircraft moves through the air. On the other side, in the hover flight mode of the aircraft, the first and second wing arrangements rotate such as wings or blades of a helicopter, so that the wing itself generates the lifting force in the hover flight mode. This is more efficient due to the large wing length and resulting rotor square area in comparison to lift generating propulsion engines in known VTOL aircraft. For example, known VTOL aircraft generate the lift by engine power directly.

Specifically, in the hover flight mode, the first rotary wing axis comprises a first rotary wing axis section of the first wing and a further first rotary wing axis section of the further first wing of the first wing arrangement. In the fixed-wing flight mode, the first rotary wing axis section and the further first rotary wing axis section have an angle between each other which is less than 180° and the wing tips are closer to the fuselage nose than the wing roots, so that first wing swept is a forward wing swept. That can also be a fixed backwards sweep, if the overall configuration of the aircraft centre of gravity needs that.

According to a further exemplary embodiment, the first wing arrangement comprises a first wingspan and the second wing arrangement comprises a second wingspan, wherein the first wingspan is e.g . longer than the second wingspan. In particular, the first wing arrangement comprises a larger aerodynamical area for generating lift than the second wing arrangement for generating longitudinal stability. The wingspan of the first and second wing arrangement may be defined by the distance of the respective tip ends of the respective wing arrangements in the fixed wing flight mode.

Particularly, the second wingspan may be shorter than approximately the half of the first wingspan, in particular approximately shorter than 1/3 of the first wingspan.

The first wing arrangement may be arranged to the fuselage in the fixed-wing flight mode with a wing swept which is a first forward wing swept but can also be a backward swept. The difference of the swept might be depending on the best position of the center of gravity for the overall configuration.

The first wing arrangement comprises a first wing swept which may be a first forward wing swept. In particular, the first longitudinal wing axis may be an axis that may define an angle with respect to the fuselage axis. If the first longitudinal wing axis is e.g . perpendicular to the fuselage axis a so called straight wing design is formed . If the tip end of the first wing arrangement are located in comparison to the wing root closer to the direction of the nose of the fuselage along the fuselage axis than the root section of the first wing arrangement which is mounted to the fuselage, the angle between the first longitudinal wing axis and the fuselage is defined negative and a so called forward wing configuration of the first wing arrangement is formed . The angle of the first wing swept or the second wing swept may be defined as the angle between the respective rotary wing axis and the fuselage axis. The respective leading edges or trailing edges of the respective wings of the respective wing arrangements may run parallel or non-parallel with the longitudinal wing axis. The rotary wing axis may be parallel or non-parallel with the longitudinal wing axis.

Generally, if the longitudinal wing axis of a wing arrangement comprises an angle different to 90° to the fuselage axis, a wing swept exists. Specifically, if a (first or second) rotary wing axis section and a further (first or second) rotary wing axis section of a respective first or second rotary wing axis comprise an angle between each other, the wing and the further wing of the respective first or second longitudinal wing arrangement may comprise a wing sweep, in particular a forward or anyward (backward) swept, a swept, an oblique wing or a variable swept (swing wing). This invention is not limited to any sweep.

The centre of gravity may be located approximately in the fuselage region so that by a forward swept of the first wing arrangement a centre of gravity of the aircraft may be positioned more forward, compared to a straight wing configuration, for example. This is advantageous, in particular since in the fixed wing flight mode, the centre of gravity can be located preferably more forward to the nose of the fuselage, i.e. in the hover flight as much downward to the tail, as possible, if the tail of the fuselage stands on the ground, for example. Furthermore, by the forward swept, in the hover flight mode, the rotor (first wing arrangement) is farer from the ground as possible (i.e. in the most opposite position of the fuselage to the ground that is the back). Hence, the foreign object damage (FOD) from the ground is reduced. An air flowing over a swept wing tends to move spanwise towards the rearmost end of the wing . On a rearward -swept wing this is outwards towards the tip, while on a forward-swept wing it is inwards towards the root. As a result, the dangerous tip stall condition of a rearwards swept design becomes a safer and more controllable root stall on a forward swept design. This allows full aileron control despite loss of lift, and also means that drag-inducing leading edge slots or other devices are not required.

The second wing arrangement may provide stabilizing functions for the aircraft. For example, if the first wing arrangement is mounted to the fuselage spaced from the centre of gravity of the aircraft along a first direction along the fuselage axis, the second wing arrangement may be mounted to the fuselage spaced from the centre of gravity in an opposite second direction along the fuselage axis with respect to the first direction. Hence, in particular in the fixed wing flight mode, a stabilized flight may be achieved . According to a further exemplary embodiment, the second wing arrangement is arranged to the fuselage in the fixed-wing flight mode with a second wing swept. According to a further exemplary embodiment, the second wing swept is a second rearward wing swept or a forward wing swept. According to a further exemplary embodiment, the second wing arrangement comprises a variable swept.

According to a further exemplary embodiment, wherein the first wing arrangement and/or the second wing arrangement comprises a dihedral angle or an anhedral angle. The dihedral angle is an upward angle of the respective wing of a respective wing arrangement from a horizontal (plane), if the fuselage is orientated along the horizontal plane. The anhedral angle is the negative dihedral angle, that is, when there is a downward angle from the horizontal (plane), if the fuselage is orientated along the horizontal plane. The dihedral angle or anhedral angle have an influence on the so called dihedral effect which is the amount of roll moment produced per degree (or radian) of sideslip. Dihedral effect is a critical factor in the stability of an aircraft about the roll axis (the spiral mode).

According to a further exemplary embodiment, the first wing arrangement and/or the second wing arrangement is free of any propulsion units.

According to a further exemplary embodiment, the fuselage comprises a propulsion unit which is arranged to the fuselage.

For example, the propulsion unit within the fuselage comprises a first rotating direction (e.g . with its propeller, shafts and/or blades) around the fuselage axis. The rotating direction of the respective wing arrangements in the hover flight mode may be aligned such that the respective wing arrangement rotates in an opposed rotating direction with respect to the first rotating direction. Hence, a proper flight control of the aircraft is achieved.

The propulsion unit may be a jet engine, a turbo jet engine, a turbo fan, a turbo prop engine, a prop fan engine, a rotary engine, rocket propulsion engines and/or a propeller engine. A driving shaft of a propeller piston engine and/or a turbine shaft of a jet engine may define a rotary axis, for example. Alternatively or additionally, a propulsion unit is mounted to the first and/or second wing arrangement. If the propulsion unit is mounted to a wing arrangement, the propulsion unit may be pivotable around the rotary wing axis or any other with respect to and relative to the respective wing

arrangement or together with a tilting of the respective wing arrangement. The propulsion unit(s) (i.e. the engines) may be installed in a different position to the propelling medium (e.g. propeller) and connected with a shaft and gearbox. So, the best aerodynamic position for the propelling medium can be used, while having the lowest possible centrifugal force effects (hence the propulsion unit is usually positioned as far inside of the wing as possible) on the propulsion unit in the hover flight mode.

According to a further exemplary embodiment, also two or more propulsion units may be installed within the fuselage. In order to provide a better flight characteristic, each of the propulsion unit comprise with respect to each other a different opposed rotating direction of their rotatable parts (e.g. shafts, propellers, blades). Hence, the torque induced by each propulsion unit may be balanced and cleared.

Propulsion units may be installed in the fuselage and the thrust is transported further on to the wings via a piping system. Moreover, the propulsion unit may be driven by electrical power or by fuel, such as hydrogen or kerosene. The necessary fuel tank or batteries may be installed in the fuselage or in the respective wing arrangement. Between the battery or the tank and the propulsion devices, a supply line system may be installed, so that in particular power or fuel may be directed from the fuel tank or the battery to the respective propulsion device. Hence, the batteries or the fuel tanks may be installed to desired locations spaced from the propulsion units, so that a beneficial balance point adjustment of the aircraft may be achieved .

In an exemplary embodiment, the propulsion unit may be adapted for generating a thrust of 3 kg to 5 kg (kilograms). In the hover flight mode, approximately 25 kg are liftable. The aircraft for vertical take-off and landing may thus have a thrust-to-weight ratio of approximately 0,2 to 0,4, preferably 0,3.

According to a further exemplary embodiment, the aircraft comprises an air distribution system arranged inside the fuselage and at least inside the first wing arrangement. The air distribution system comprises an air suction unit (e.g. a (gas) compressor or e.g. a turbine compressor stage of the propulsion unit of the aircraft) for generating pressurized air and a tubing. The air suction (e.g . an aircraft gas turbine) unit is in particular mounted to the fuselage. The first wing arrangement comprises at least one nozzle section for blowing out air such that thrust is generatable. The tubing couples the nozzle section to the air suction unit for guiding the pressurized air from the air suction unit to the nozzle. Hence, a tip jet configuration is generated. The air suction unit is mounted to the aircraft such that air is sucked inside the fuselage and fed via the tubing of the air distribution system to the nozzle sections for generating thrust. The tubing is partially arranged inside the wings such that the fed air is guided to the nozzle sections that propel the rotation of the rotor (wing arrangement) in hover mode as well as the forward flight in fixed wing configuration . This can also be used for thrust vectoring purposes. Through the nozzles section, also an exhaust plume of a propulsion unit may be exhausted .

By the present exemplary embodiment, the suction unit may be installed to a suitable location with respect to the balance point (i.e. the centre of gravity) of the aircraft. At the nozzle sections (e.g. at a tip end of a respective wing) where thrust is generated, it is only necessary to install very light and small nozzles to which the compressed air may be guided by the tubing . For example, if the nozzle sections are located at the tip ends of the respective wings, the heavier air suction unit may be installed to the fuselage. No further heavy and complex installations have to be installed to the wings except of small holes that contains or form the nozzles. Hence, a very light and balanced propulsion system may be generated .

For example, the thrust that is generated by the nozzles may cause propulsion of the aircraft in the fixed-wing flight mode. In this mode, the direction of the thrust of the nozzle sections may be parallel and may comprise substantially the same thrust direction. In the hover flight mode, the respective wings of the respective wing arrangements are tilted up to opposite direction or beyond with respect to each other, such that for example the respective nozzle sections at the respective wings, e.g . one installed at the left wing and the other installed at the right wing of a respective wing arrangement, generate thrust generally in opposite direction with respect to each other. Thus, if for example thrust is generated at the tip end of one wing in a first direction and further thrust is generated at the opposed tip end of the other wing in an opposed direction with respect to the first thrust direction at the one wing, a rotation of the respective wing arrangement around the longitudinal fuselage axis is generated . By the rotation, the hover flight mode is enabled .

In particular, no big masses have to be installed to the wings and to the tip end of the wings. Hence, the induced centrifugal force, caused by the rotation of the wings and the masses mounted to the wing may be reduced, so that better and lighter materials may be used .

According to a further exemplary embodiment, the first wing arrangement and/or the second wing arrangement comprises a plurality of nozzle sections connected to the air distribution system for blowing out the air such that thrust is generatable. Each of the plurality of nozzle sections is controllable in such a way that the thrust generated by each of the plurality of nozzle sections is adjustable individually. Hence, the thrust direction of each nozzle may be adjusted independently, so that the flight direction and the

stabilization of the aircraft in the fixed-wing flight mode and the hover flight mode may be controlled and stabilized further. For example, in a transition status between the hover flight mode and the fixed-wing flight mode, it may be a position, in which the aircraft is still too slow, so that no lift by the fixed wings is generated, and the rotation of the wings may be already too slow, so that not enough lift by the rotation of the wings is generated. Thus, in order to stabilize the aircraft in the transition status, the thrust direction of the nozzles may generate the stabilization of the aircraft till the rotation of the wings is high enough in the hover flight mode or till the speed of the aircraft through the air is fast enough for generating lift in the fixed-wing flight mode. In operation, e.g. a side sweep can be counter-acted by this system.

According to a further exemplary embodiment, the air distribution system comprises an air distribution centrifuge. The air distribution system comprises an inner ring and an outer ring which is rotatable relatively to the inner ring . The inner ring is mounted to the fuselage. The outer ring is mounted to the first wing arrangement, i.e. to the first wing and to the further first wing . The inner ring and the outer ring are arranged with respect to each other, such that an air chamber is formed therebetween. The inner ring comprises an air inlet for injecting the pressurized air from the air suction unit (e.g . from a turbine pressure stage of the propulsion unit of the aircraft) into the air chamber. The outer ring comprises an air outlet for exhausting the pressurized air from the air chamber to the nozzle sections. In particular, the outer ring is coupled to the tubing which connects the air outlet with the nozzle sections. Hence, the wings may rotate around the fuselage axis and hence around the air suction unit, wherein the air suction unit is located non-rotatable inside the fuselage. The air is guided to the nozzle sections from the suction unit via the air chamber. A respective further distribution centrifuge may be installed between the fuselage and e.g. the second wing arrangement.

According to a further exemplary embodiment, the fuselage comprises a first fuselage part and a second fuselage part. The first fuselage part and the second fuselage part are arranged one after another along the fuselage axis, wherein the first wing arrangement and the second wing arrangement are mounted to the first fuselage part.

Specifically, according to a further exemplary embodiment, the first fuselage part is rotatable around the fuselage axis with respect to the second fuselage part. Hence, in the first fuselage part, all equipments which rotate together with the respective first and second wing arrangements in the hover flight mode may be stored and mounted. To the second fuselage part, all

equipments which need a stable and non-rotating position, such as cameras for observing the ground or a cockpit for a pilot, may be arranged in the second fuselage part.

The first fuselage part and the second fuselage part may be coupled for example by a roller bearing, such that the first fuselage part is rotatable around the fuselage axis with respect to the second fuselage part. In particular, the first fuselage part may overlap in a transition section the second fuselage part, wherein in the transition section a roller bearing between the first and second fuselage part is arranged.

According to a further exemplary embodiment, the fuselage, and in particular the second fuselage part, comprises a landing gear, in particular an extendible or foldable landing gear. By the landing gear, such as landing pillars or landing wheels, the aircraft stands on a ground. The landing gear may be used for counteracting to sidewinds during takeoff and landing . The landing gear at the upwind (luv) side of the aircraft may reduce its length at the downwind (lee) side of the aircraft increases its length in order to align the rotor axis/ fuselage axis of the rotating wing arrangement and/or the fuselage nose forward to the upwind side.

Furthermore, the gear may be arranged such that while extending the landing gear, the aircraft is set up. For example, if the aircraft lies on the ground, the aircraft/fuselage may be positioned to a start position by extending the landing gear.

For example, when starting the aircraft in the hover flight mode, the first fuselage part may rotate around the fuselage axis, such that the first wing arrangement and the second wing arrangement rotates around the fuselage axis so that a lift is generated. On the other side, the second fuselage part stands non-rotatable on the ground on the landing gear and/or the third wing arrangement until sufficient lift for lifting the aircraft is generated .

According to a further exemplary embodiment, the first wing arrangement and/or the second wing arrangement comprise controllable control surfaces, such that the aircraft is controllable. In particular, the second wing

arrangement comprises controllable control surfaces such that the second wing arrangement is adapted for the use as a rudder in the fixed wing mode. In particular, the second wing arrangement may be mounted to the fuselage in such a way, that the complete aerodynamical area of the second wing arrangement may function as a rudder. Hence, the complete aerodynamical surface of the second wing arrangement may function as a control surface and the complete second wing arrangement may be pivoted with respect to the fuselage in order to control the flight of the aircraft.

Moreover, the respective wing arrangements wing may comprise control surfaces, such as an aileron or a rudder, for example. Hence, in the fixed wing mode, the first wing arrangement and the second wing arrangement may be controlled in such a way that the areodynamical surfaces of the first wing arrangement and the second wing arrangement may be used as control surfaces, such as aileron surfaces.

According to a further exemplary embodiment, the first wing arrangement is mounted to the fuselage at a first mounting location and wherein the second wing arrangement is mounted to the fuselage at a second mounting location.

Specifically, the first mounting location and the second mounting location are spaced along the fuselage axis. According to a further exemplary embodiment, the aircraft further comprises a third wing arrangement. The third wing arrangement is mounted to the fuselage at a third mounting location, wherein the third mounting location is spaced to the first mounting location and the second mounting location along the fuselage axis. According to a further exemplary embodiment, the first wing arrangement comprises a first wing and a further first wing . The first rotary wing axis is split in a first rotary wing axis section and a further first rotary wing axis section. The first wing extends along the first rotary wing axis section and the further first wing extends along the further first rotary wing axis section from the fuselage. The first wing is tiltable with the first rotational direction around the first rotary wing axis section and the further first wing is tiltable with a further first rotational direction around the further first rotary wing axis section.

According to a further exemplary embodiment, the first rotational direction differs to the further first rotational direction.

Accordingly, according to a further exemplary embodiment, the second wing arrangement comprises a second wing and a further second wing . The second rotary wing axis is split in a second rotary wing axis section and a further second rotary wing axis section. The second wing extends along the second rotary wing axis section and the further second wing extends along the further second rotary wing axis section from the fuselage. The second wing is tiltable with the second rotational direction around the second rotary wing axis section and the further second wing is tiltable with a further second rotational direction around the further second rotary wing axis section. According to a further exemplary embodiment, the second rotational direction differs to the further second rotational direction.

In particular, if the first wing extends from one side of the fuselage and the further first wing extends from the opposed side of the fuselage, and the first wing and the further first wing rotates around the fuselage axis, it may be necessary that the respective wing edges, i.e. the leading edges of the wings, are moved through the air such that the air impacts (attacks) at the leading edge instead of the trailing edge, so that lift is generated by the wing profile. Hence, for the transformation of the aircraft from the fixed-wing flight modus to the hover flight modus, the first wing may rotate around its first wing longitudinal axis section around approximately 60° (degrees) to approximately 120°, in particular approximately 90°, in the first rotational direction and the further first wing may be tilted around approximately 60° (degrees) to approximately 120°, in particular approximately 90°, around the further first wing longitudinal axis section in the further first rotational direction, which is an opposed direction with respect to the first rotational direction. In an alternative embodiment it is as well possible that the first rotational direction and the second rotational direction are equal. In a further exemplary embodiment, the aircraft may comprise further wing arrangements, e.g. a fourth or a sixths wing arrangement. The further wing arrangement may be retractable for example. In the fixed-wing mode, the further wing arrangements may form a double-decker, for example. According to a further exemplary embodiment, the aircraft comprises a sleeve to which the first wing arrangement and/or the second wing arrangement is/are mounted . The sleeve is slidably mounted to the fuselage such that the sleeve is slideable along a surface (i.e. along a centre axis/fuselage axis of the fuselage) of the fuselage and such that the sleeve is rotatable around the fuselage axis. Furthermore, a further sleeve may be attached to the fuselage as described above, wherein to each of the sleeves a respective wing arrangement may be mounted.

Hence, the respective wing arrangements are attached by the sleeve(s) to the fuselage. By using the sleeve, the respective wing arrangements may e.g. surround the fuselage and thus not run through the fuselage, e.g . for fixing purposes. Hence, a relative motion between the respective wing arrangements and the fuselage by using the sleeve is achieved . The respective wing arrangements are rotatably fixed to the circumferential surface of the sleeve to the fuselage. The sleeve may be a closed or open sleeve to which the respective wing arrangements are attached, e.g. at the outer surface of the sleeve. Furthermore, the sleeve is slideably clamped (e.g. by its inner surface) to the outer surface of the fuselage, wherein between the sleeve and the fuselage a slide bearing is formed. Besides the slide bearing, the sleeve and the outer surface of the fuselage may be adapted to form e.g. a ball bearing, so that abrasion is reduced.

Between the inner surface of the sleeve and the outer surface of the fuselage, a bearing ring may be interposed which is non-rotatably fixed either to the fuselage or to the respective wing arrangements. For example, the sleeve may be slidable with respect to the bearing ring, wherein the bearing ring is fixed to the fuselage without being slidable.

Alternatively, according to a further exemplary embodiment, the bearing ring is slidably mounted to the fuselage such that the bearing ring is slideable along a surface of the fuselage and such that the bearing ring is rotatable around the further rotary axis. The sleeve may rotate together with the bearing ring around the further rotary axis. The further rotary axis may be changed in direction by controls, e.g. servos. Further alternatively, according to a further exemplary embodiment, the bearing ring is rotatably mounted to the fuselage such that the bearing ring is rotatable around the fuselage axis of the fuselage but wherein the bearing ring is mounted to the fuselage such that the bearing ring is not moveable along the fuselage axis. The sleeve to which the respective wing arrangements are mounted is moveable with respect to the bearing ring along the fuselage axis and the sleeve rotates together with the bearing ring around the fuselage axis. The bearing ring may comprise roller bearing elements, which are located between the bearing ring and the fuselage surface, such that the bearing ring is rotatable around the fuselage.

For providing the above described fixation of the wing arrangement to the fuselage by the sleeve, according to a further exemplary embodiment, the aircraft comprises a first fixing element (e.g . a first bolt) and a second fixing element (e.g . a second bolt). The sleeve comprises an elongated through hole, which may have an extension approximately parallel to the fuselage axis. The first fixing element and the second fixing element are coupled, e.g. in a rotatable manner, spatially apart from each other to one of the wing

arrangements. The first fixing element is further coupled to the sleeve and the second fixing element is further coupled through the elongated through hole to the fuselage or the bearing ring, respectively. The first fixing element and the second fixing element may be for example a first bolt and a second bolt or a first wing spar and a second wing spar of the respective wing arrangement, respectively. Respective first ends of the first and second fixing elements are for example rotatably coupled to a root section of the respective wing arrangement. The opposed ends of the respective first and second fixing elements are for example rotatably coupled to the sleeve and rotatably fixed to the fuselage or the bearing ring .

The second fixing element which couples the respective wing arrangement to the fuselage or the bearing ring forms a pivot point through which the respective rotary wing axis of the respective wing arrangement runs. The respective wing arrangement is thus rotatable around the pivot point.

For example, if the sleeve is moved along the surface of the fuselage or the bearing ring, e.g. along the fuselage axis, the first fixing element (e.g . bolt) moves together with the sleeve, whereas the second fixing element (e.g . bolt) which is fixed to the fuselage or the bearing ring does not move along the further rotary axis. Hence, by moving the sleeve and hence the first fixing element along the fuselage, the respective wing arrangement pivots around the pivot point, e.g . around its respective rotary wing axis. The tilting of the respective wing arrangement around the rotary wing axis and hence the movement of the sleeve along the bearing ring or the fuselage, respectively, may be initiated by a control force, which may be generated by e.g . servo motors or mechanical mechanism. By the above described fixing mechanism for the respective wing

arrangements to the fuselage, a robust mechanism for the tilting of respective wing arrangements is formed .

In particular, the first fuselage part may function as the above-described sleeve. In other words, the first fuselage part and the sleeve may be integrally formed .

Furthermore, the first wing arrangement, the second wing arrangement and the first fuselage part, the second fuselage part and the propulsion unit may be detachably attached to each other so that an aircraft kit is provided which is easy to transport and which can be reassembled in a fast manner.

Furthermore, due to the modular design, defect parts may be substituted very simple. Furthermore, according to a further exemplary embodiment, the aircraft comprises a swash plate which is coupled to the fuselage. The first wing arrangement and/or the second wing arrangement are coupled to the swash plate. The swash plate is movable with respect to the fuselage axis in a controllable manner, such that the orientation and the location of the respective first wing arrangement and/or the second wing arrangement with respect to the fuselage axis are amendable. Hence, by controlling the swash plate, a flight control of the aircraft in particular in the hover flight mode is achievable. By adjusting the orientation and the location of the respective first wing arrangement and/or the second wing arrangement with respect to the fuselage axis, a forward movement of the aircraft in the hover flight mode is realizable.

There is a possibility by electronic control of ailerons on the rotor to control hover flight. In further exemplary embodiments, the wing arrangements and the fuselage may be designed and formed as follows:

The first and/or second wing arrangement may comprise a forward wing swept or a rearward wing swept in the fixed wing flight mode such that more design freedom to locate the centre of gravity is given. Furthermore, the rotary wing axis of a respective wing arrangement is parallel or non parallel with respect to the longitudinal wing axis of the respective wing arrangement. The rotating wing arrangement may also have a wing swept in the hover flight mode such that the rotating wing arrangement forms a plate like shape during rotation

The rotation of the respective rotating wing arrangement around the fuselage may be in opposite direction with respect to a rotational direction of a propulsion unit within the aircraft. By the wheels of the landing gear, the aircraft is controllable during a movement on the ground.

It has to be noted that embodiments of the invention have been described with reference to different subject matters. In particular, some embodiments have been described with reference to apparatus type claims whereas other embodiments have been described with reference to method type claims.

However, a person skilled in the art will gather from the above and the following description that, unless other notified, in addition to any combination of features belonging to one type of subject matter also any combination between features relating to different subject matters, in particular between features of the apparatus type claims and features of the method type claims is considered as to be disclosed with this application.

BRIEF DESCRIPTION OF THE DRAWINGS

The aspects defined above and further aspects of the present invention are apparent from the examples of embodiment to be described hereinafter and are explained with reference to the examples of embodiment. The invention wwiill be described in more detail hereinafter with reference to examples of embodiment but to which the invention is not limited.

Fig. 1 shows an exemplary embodiment of the aircraft, wherein the aircraft is shown in a fixed wing flight mode according to an exemplary embodiment of the present invention;

Fig. 2 shows a further exemplary embodiment of the aircraft which is shown in a hover flight mode according to an exemplary embodiment of the present invention;

Fig . 3 shows a schematical view of an air distribution system of the aircraft according to an exemplary embodiment of the present invention; Fig. 4 and Fig. 5 show views of an aircraft with a preferred wing design according to an exemplary embodiment of the present invention;

Fig. 6 shows an aircraft with an X-configuration and landing gears according to an exemplary embodiment of the invention;

Fig. 7 shows an aircraft with an X-configuration comprising two propulsion units and two exhaust nozzles according to an exemplary embodiment of the present invention;

Fig. 8 and Fig. 9 show an aircraft with an X-configuration and anhedral and dihedral wing arrangements according to an exemplary embodiment of the present invention;

Fig . 10 shows an aircraft with an X-configuration according to an exemplary embodiment of the present invention;

Fig. 11 shows an aircraft with three wing arrangements forming a delta wing configuration according to an exemplary embodiment of the present invention;

Fig . 12 shows an aircraft comprising a wing arrangement with differently aligned tip ends of a respective wing arrangement;

Fig. 13 shows an aircraft comprising an anhedral wing configuration according to an exemplary embodiment of the present invention; Fig . 14 shows an aircraft comprising three wing arrangements forming a delta wing configuration according to an exemplary embodiment of the present invention;

Fig. 15 shows an aircraft comprising a wing arrangement with a nozzle section according to an exemplary embodiment of the present invention;

Fig . 16 shows an aircraft comprising two wing arrangements with a nozzle section according to an exemplary embodiment of the present invention; and Fig. 17 shows an aircraft comprising two wing arrangements and two exhaust flaps according to an exemplary embodiment of the present invention. DESCRIPTION OF EXEMPLARY EMBODIMENTS The illustration in the drawing is schematically. It is noted that in different figures, similar or identical elements are provided with the same reference signs.

Fig. 1 shows an aircraft comprising a fuselage 100 with a fuselage axis 101. The aircraft further comprises a first wing arrangement 110 which is mounted to the fuselage 100 such that the wing arrangement 110 is tiltable along a first rotary wing axis 111, 111' of the first wing arrangement 110 and such that the first wing arrangement 110 is rotatable around the fuselage axis 101. The aircraft further comprises a second wing arrangement 120 which is mounted to the fuselage spaced apart from the first wing arrangement 110 along the fuselage axis 101.

The first wing arrangement 110 and/or the second wing arrangement 120 are adapted in such a way that, in a fixed wing mode, the first wing arrangement 110 and/or the second wing arrangement 120 do not rotate around the fuselage axis 101.

The first wing arrangement 110 is further adapted in such a way that, in a hover flight mode (See Fig. 2), the first wing arrangement 110 is tilted around the respective first rotary wing axis 111 with respect to its orientation in the fixed wing flight mode and that the first wing arrangement 110 rotates around the fuselage axis 101, such that a lift is generated by the rotation of the first wing arrangement 110 around the fuselage axis 101. Furthermore, the first wing arrangement 110, which is rotatable in the hover flight mode, comprises an extendible lift increasing system 114 which is arranged to the first wing arrangement 110 for selectively amending a lift area of the first wing arrangement 110 in the fixed-wing flight mode and the hover flight mode.

As shown in Fig. 1, the extendible lift increasing system 114 comprises flaps which are arranged, e.g . hinged, at a trailing edge of the first wing

arrangement 110. In Fig . 1, the aircraft is shown in a fixed wing flight mode. In order to increase the lift area of the first wing arrangement 110, the flaps of the lift increasing system 114 are extended. Additionally, within the scope of the present invention, the extendible lift increasing system 114 may comprise slats, which are hinged to a leading edge of the first wing arrangement 110. Furthermore, to the second wing arrangement 120 also a further extendible lift increasing system may be arranged, which comprises extendible flaps at the trailing edge and/or slats at the leading edge of the second wing

arrangement 120.

Furthermore, as can be taken from Fig. 1, respective exhaust flaps 107 may be attached . Through the exhaust flaps 107, an exhaust gas from the propulsion unit 106 may be exhausted. The exhaust flaps 107 may selectively control the exhaust gas stream of the exhaust gas. Hence, the exhaust gas stream may be guided by the exhaust flaps 107 for example to the side of the aircraft and away from the ground, such that the dust generation and the raising of dust, respectively, may be reduced .

In the exemplary embodiment in Fig. 1, the fuselage 100 comprises a nose 102 and a tail 103. Furthermore, the fuselage 100 comprises a first fuselage part 104 and a second fuselage part 105 which are arranged one after another along the fuselage axis 101. The first wing arrangement 110 comprises a first wing 112 and a further first wing 113. The first wing 112 and the further first wing 113 extend from the fuselage along a first rotary wing axis 111 and along a further first rotary wing axis 111'. In particular, the first wing 112 and the further first wing 113 are tiltable around their respective first longitudinal wing axes 111, 111'. The first wing 112 extends along the first rotary wing axis from the fuselage 100 and the further first wing 113 extends along the further first rotary wing axis 111' from the fuselage 100. The first wing arrangement 110 is arranged to the fuselage 100 in the fixed wing flight mode with a first wing swept which is a first forward wing swept (- Θ) . Hence, the swept angle Θ between a first longitudinal wing axis 115, 115' and fuselage axis 101 is less than 90° and defined negative (i.e. -Θ) .

Accordingly, the second wing arrangement 120 comprises a second wing 122 and a further second wing 123. The second wing 122 and the further second wing 123 comprise respective second rotary wing axes 121, 121'. In an exemplary embodiment, the second wing 122 and the further second wing 123 are tiltable around their respective second rotary wing axes 121, 121' as indicated by the arrows.

As shown in Fig . 1, the second wings 122, 123 form a rearward wing swept. Hence, the swept angle Θ between a respective second longitudinal wing axis 125, 125' and the fuselage axis 101 is defined positive. In an exemplary embodiment, each of the wing arrangements 110, 120 may comprise three or more wings.

Furthermore, as shown in Fig . 1 , the first wing arrangement 110 is mounted to a first fuselage part 104 and the second wing arrangement 120 is mounted to a second fuselage part 105. The first fuselage part 104 comprises a first length along the fuselage axis 101 and the second fuselage part 105 comprises a second length along the fuselage axis 101. Specifically, the first length of the first fuselage part 104 is smaller than the second length of the second fuselage part 105. More specifically, the first length of the first fuselage part 104 is smaller than 1/6 or smaller than 1/10 of the second length of the second fuselage part 105.

A third wing arrangement 130, which comprises for example two or more wings, is attached to a second fuselage part 105. The third wing arrangement 130 may generate lift when moving the aircraft through the air in the fixed wing flight modes and thus stabilize the aircraft during flight, e.g. like a v- canard configuration. Furthermore, the third wing arrangement 130 may be tiltable around the respective third rotary wing axis by a control unit, such that the third wing arrangement may function as a rudder for controlling the aircraft during flight in the fixed wing flight mode. It is also possible to use all wings of the wing arrangements 110, 120, 130 as ailerons. Therefore, a shift mechanism which controls the configuration from the fixed wing mode to the hover flight mode can be used .

Furthermore, the aircraft shown in Fig. 1 comprises a propulsion unit 106 which is mounted to the fuselage 100. For example, the propulsion unit is installed inside the fuselage 100, wherein through the nose 102 of the fuselage 100 air may be sucked in by the propulsion unit 106. At the tail 103 of the fuselage, the propulsion unit 106 may exhaust the air for generating thrust.

Fig. 2 shows an exemplary embodiment of the aircraft in a hover flight mode.

The orientation of the first wing arrangement 110 differs to the orientation of the first wing arrangement 110 as shown in Fig . 1. Specifically, the first wings 112, 113 are tilted around the respective first longitudinal wing axes 111, 111'. The first wings 112, 113 may rotate around the fuselage axis 101. Due to the rotation of the respective wing arrangement 110 around the fuselage axis 101, lift is generated such that the aircraft is operable in the hover flight mode, e.g . such as a helicopter. Therefore, the first wing arrangement 110 is coupled e.g. to the first fuselage part 104. The first fuselage part 104 is rotatable around the fuselage axis 101.

On the other side, the second fuselage part 105, which is coupled rotatably to the first fuselage part 104, does not rotate. Hence, the aircraft may stand by the landing gear 201 which is mounted to the fuselage 100 on a ground, although the first fuselage part 104 and the respective first wing arrangement 110 rotates. The third wing arrangement 130 may be mounted to the second fuselage part 105 and does not rotate around the fuselage axis 101.

The landing gear 201 may be extendible and adjustable to the formation of the ground . Furthermore, the first wing arrangement 110 may still comprise the forward wing swept. Alternatively, the first wing arrangement may comprise a wing adjusting mechanism such that the first wing swept is amendable. Hence, in the hover flight mode, the first wing arrangement 110 may form a straight wing configuration and in the fixed wing flight mode a forward or rearward swept.

Fig. 3 shows an air distribution system for providing an air propulsion system. The air distribution system comprises an air suction unit 304 which is arranged inside the fuselage 100. The air suction unit 304 sucks in air e.g. from the nose 102 of the fuselage 100. The air suction unit 304 generates pressurized air. Furthermore, the air distribution system comprises a tubing 303 which guides the pressurized air from the air suction unit 304 to nozzle sections 307 which are located at the respective first wings 112, 113. The pressurized air which is blown out through the nozzle sections 307 generates thrust.

The thrust generated by the nozzle sections 307 has a desired thrust direction, wherein the thrust direction depends on the adjustment of the nozzle sections 307 and the adjustment of the respective wings 112, 113. For example, in the hover flight mode, the nozzle sections 307 of the first wing 112 are directed in opposite direction with respect to the nozzle sections 307 of the second wing 113. Hence, the rotation of the first wing arrangement 110 around the fuselage axis 101 is generated . By the rotation of the wing arrangement 110 around the fuselage axis 101 lift for lifting the aircraft in the hover flight mode is generated. In the fixed wing flight mode, the first wing 112 and the further first wing 113 are orientated with respect to each other in such a way, that the nozzle sections 307 generate thrust in a generally similar thrust direction. Hence, a forward movement and a forward thrust are generated by the exhausted pressurized air such that a forward movement of the aircraft to the air is generated. Thereby, in the fixed wing flight mode, lift is generated by moving the first wing arrangement 110 through the air.

Specifically, as shown in Fig . 3, the pressurized air is guided from the (non- rotatable) fuselage 100 to the rotating first wing arrangement 110. Thereby, an inner ring 301 is mounted to the fuselage without providing a relative movement with respect to the fuselage 100. A second outer ring 302 is mounted e.g. to the fuselage 100 or to the inner ring 301 in such a way, that the outer ring 302 is rotatable with respect to the inner ring 301. The outer ring 302 may be coupled to the inner ring 301 e.g . by a roller bearing .

Between the inner ring 301 and the outer ring 302, an air chamber is formed. The pressurized air from the air suction unit 304 is guided through an inlet opening through the inner ring 301 into the air chamber. The outer ring 302 comprises an air outlet, such that the pressurized air is guided from the air chamber through the outlet opening in the outer ring 302.

Furthermore, a first wing spar 305 to which the first wing 112 is attachable and a further first wing spar 306 to which the further first wing 113 is mounted to the outer ring 302. Furthermore, a part of the tubing 301 is guided through the respective wings 112, 113. The tubing 303 is coupled to the air outlet of the outer ring 302 and with the respective nozzle section 307 of the respective wing 112, 113. Hence, by the tubing 303 the pressurized air is guided from the air chamber to the respective nozzle section 307.

Fig. 4 and Fig. 5 show views of an aircraft with a preferred wing design according to an exemplary embodiment of the present invention.

In Fig . 4, a front view of an aircraft is shown which comprises a first wing arrangement 110, a second wing arrangement 120 and a third wing

arrangement 130. The first wing arrangement 110 may be located between the third wing arrangement 130 which is located closer to nose 102 of the fuselage 100 and the second wing arrangement 120 which is located closer to the tail 103 of the fuselage 100. The first wing 112 and the further first wing 113 of the first wing arrangement 110 may comprise a forward wing swept. The second wing arrangement 120 and the respective second wings 122, 123 and further second wing 123 may form a rearward wing swept. Furthermore, the first wing arrangement 110 and in particular as shown in Fig . 4, the second wing arrangement 120, may comprise a dihedral angle or an anhedral angle.

As shown in Fig . 5, the second wing arrangement 120 and the third wing arrangement 130 may comprise an anhedral wing configuration, for example.

Fig. 6 shows a further exemplary configuration of the aircraft. The aircraft as shown in Fig. 6 comprises a fuselage 100 with a fuselage axis 101. The first wing arrangement 110 comprises a forward wing swept. Winglets are attached to the tip ends of the first wing arrangement 110. Furthermore, propulsion units 106, 106' are mounted to the first wing arrangement 110. The propulsion units 106, 106' may be for example a propeller motor.

The aircraft in Fig . 6 is shown on the right side in the fixed wing flight mode and on the left side in the hover flight mode. As can be taken from Fig . 6, the first wing arrangement 110 comprises a first rotary wing axis 111. Hence, the first wing arrangement 110 may be tilted around the first rotary wing axis 111. The rotary wing axis 111 is not perpendicular to the fuselage axis 101, for example. If the first wing arrangement 110 is tilted around the first rotary wing axis 111 from the fixed wing flight mode to the hover flight mode, the rotary wing axis 111 differs to the longitudinal wing axis 115.

Furthermore, as shown in Fig. 6, the second wing arrangement 120 comprises a rearward wing swept. Hence, the aircraft as shown in Fig. 6 forms with both wing arrangements 110, 120 a so-called X-configuration. At the wing tips of the second wing arrangement 120, landing gears 201 are attached. The landing gears 201 which are arranged at the tip ends of the second wing arrangement 120 may be extendable, for example.

Fig. 7 shows an aircraft with an X-configuration, wherein the first wing arrangement 110 comprises a forward wing swept and the second wing arrangement 120 comprises a rearward wing swept.

Furthermore, the longitudinal wing axis 115 differs to the rotary wing axis 111, 111', for example. Additionally, nozzle sections 307 are installed in the first wing arrangement 110, wherein pressurized air or pressurized exhaust gas may be exhausted in order to provide a rotation of the first wing arrangement 110 and the fuselage axis 101 in the hover flight mode or to drive the aircraft to the air in the fixed wing flight mode. Furthermore, an extendable landing gear 201 is mounted to the fuselage 100, in particular close to the tail section 103. The landing gear 201 may be adapted in such a way that the aircraft may be stand up into a start position for the hover flight mode by extending the landing gear 201.

Furthermore, as shown in Fig. 7, the fuselage 100 comprises two propulsion units 106, 106', which may be gas turbines, wherein at the nose 102 of the aircraft the air is sucked in and the exhaust gas is blown out at an opposed end/tail 103 of the fuselage 100.

Fig. 8 shows an aircraft comprising an X-configuration of the first wing arrangement 110 and the second wing arrangement 120, wherein the first wing arrangement 110 comprises a forward wing swept and the second wing arrangement 120 comprises a rearward wing swept.

Furthermore, the first wing arrangement 110 and the second wing

arrangement 120 comprise an anhedral angle, which means that the first wing arrangement 110 and the second wing arrangement 120 comprise a

downward angle from a horizontal of the wings or the tail plane of the aircraft. Furthermore, as shown in Fig . 8, the exhaust flap 107 is arranged at a bottom (or alternatively at a top) surface of the fuselage 100 if the aircraft is in the fixed wing flight mode. Hence, the hot exhaust gas may be guided through the exhaust flap 107 upwards from the aircraft. The exhaust flap 107 may also function as an air intake flap which covers an air intake through which air by the suction unit 304 (see Fig .3) is feedable.

Alternatively, the first wing arrangement 110 and the second wing

arrangement 120 may comprise respective wing arrangements 110, 120 with a dihedral angle which means that the respective wing arrangements 110, 120 extend with an upward angle from the horizontal of the wings or the tail plane of the fuselage 100. Fig. 9 shows an aircraft with an X-configuration, wherein the first wing arrangement 110 comprises a forward wing swept and the second wing arrangement 120 comprises a rearward wing swept. Furthermore, the second wing arrangement 120 has an anhedral angle and the first wing arrangement 110 comprises a dihedral angle in the fixed wing flight mode. Furthermore, a propulsion unit 106 is arranged at the fuselage 100.

Furthermore, an extendible landing gear 201 is shown, such that the aircraft may stand in the hover flight mode with both, the second wing arrangement 120 and the extendable landing gear 201 on the ground. The extendable landing gear 201 may be designed such that during extending of the landing gear 201 the aircraft is set up from a storage position into a start position.

Fig. 10 shows an exemplary configuration of the aircraft similar to Fig. 6. The aircraft as shown in Fig . 10 comprises a fuselage 100 with a fuselage axis 101. The first wing arrangement 110 comprises a forward wing swept. Winglets are attached to the tip ends of the first wing arrangement 110. Furthermore, propulsion units 106, 106' are mounted to the first wing arrangement 110. The propulsion units 106, 106' may be for example a propeller motor. The aircraft in Fig . 10 is shown on the right side in the fixed wing flight mode and on the left side in the hover flight mode. As can be taken from Fig . 10, the first wing arrangement 110 comprises a first rotary wing axis 111. Hence, the first wing arrangement 110 may be tilted around the first rotary wing axis 111. The rotary wing axis 111 is not perpendicular to the fuselage axis 101, for example. If the first wing arrangement 110 is tilted around the first rotary wing axis 111 from the fixed wing flight mode to the hover flight mode, the rotary wing axis 111 differs to the longitudinal wing axis 115.

Fig . 10 shows for example an air intake in the nose section 102 for the air suction unit 304 (see Fig. 3), such that air may be taken for the nozzle sections 307. Furthermore, in Fig . 10 an extendible landing gear 201 at a tail 103 of the aircraft is shown, which may be extended for positioning the aircraft in a desired start position.

Fig. 11 shows an aircraft comprising a first wing arrangement 110, a second wing arrangement 120, which is located at a rear end, i.e. the tail 103, of the fuselage 100, and a third wing arrangement 130 which is arranged at a nose section 102 of the fuselage 100. The first wing arrangement 110 is located to the fuselage 100 between the third wing arrangement 130 and the second wing arrangement 120. To the fuselage 100, respective propulsion units 106 are installed.

The first wing arrangement 110 and the second wing arrangement 120 may comprise a rearward wing swept, wherein the third wing arrangement 130 may comprise a forward wing swept. In the fixed wing flight mode, the first wing arrangement 115 and the third wing arrangement 130 may form an almost continuous wing area such that the aircraft shown in Fig . 11 forms a kind of a delta wing configuration together with the first wing arrangement 110 and the third wing arrangement 130. In other words, the trailing edge of the third wing arrangement 130 may be parallel with a part of the leading edge of the first wing arrangement 110 in the fixed wing flight mode, wherein between the parallel trailing edge of the third wing arrangement 130 and the section of the leading edge of the first wing arrangement 110 only a small gap exists. Furthermore, as shown in Fig. 11, the rotary wing axis 111, 111' differs to the longitudinal wing axis 115.

Fig. 12 shows an aircraft in a hover flight mode, wherein the aircraft comprises the first wing arrangement 110 and the second wing arrangement 120. In particular, the first wing 112 of the first wing arrangement 110 and the further first wing 113 of the first wing arrangement 110 are shown. The first wing 112 and the further first wing 113 comprise respective tip end sections at which the nozzle sections 307, 307' are installed . In particular, the tip end section of the first wing 112 comprises a snapped-off, angled section with respect to the main section of the first wing 112. In other words, the tip end section of the first wing 112 comprises a longitudinal extension which differs to the longitudinal wing axis 115 of the first wing 112. The tip end section of the further first wing 113 comprises a longitudinal extension which differs to the longitudinal wing axis 115'. Specifically, as shown in Fig. 12, the tip end section of the first wing 112 is bended or buckled in an opposed direction with respect to the tip end section of the further first wing 113.

Fig. 13 shows an aircraft with the first wing arrangement 110 and the second wing arrangement 120, wherein both wing arrangements 110, 120 comprise a rearward wing swept. At the tip ends of the first wing arrangement 110 propulsion units 106, 106' are arranged .

The second wing arrangement 120 comprises four wings. At the nose 102 of the fuselage 100, a cockpit 1301 is installed, wherein the cockpit 1301 comprises a glass window. In the cockpit 301, a pilot or sensors, such as cameras, may be installed.

Fig. 14 shows an aircraft comprising a first wing arrangement 110, a second wing arrangement 120 and a third wing arrangement 130. Respective leading edges of the first wing arrangement 110 and the third wing arrangement 130 are parallel with respective leading edges of adjacent wing arrangements 120, 110, 130. Hence, because only small gaps between the respective wing arrangements 110, 120, 130 in the fixed wing flight mode exist, a delta wing configuration of the aircraft is provided. In Fig . 14, at the upper side the aircraft is shown in a hover flight mode, wherein the first wing arrangement 110 is rotated around the first wing rotary axis 111. At the lower side in Fig . 14, the aircraft is shown in the fixed wing flight mode. As can be taken from Fig . 14, the propulsion units 106, 106' are arranged at the first wing arrangement 110.

Fig. 15 shows a further exemplary embodiment of the fuselage, wherein the air suction unit 304 sucks in an airstream 1501 , wherein the airstream 1501 is deflected by the tubing 303 to a nozzle section 307 which is installed at a tip end of the first wing arrangement 110. A cockpit 1301 comprising e.g . a camera is arranged at a nose section 102 of the fuselage 100.

The aircraft may comprise an air deflecting element 1502, which may comprise a sleeve which is attached to an air intake of the fuselage. The air deflecting element 1502 may deflect the injected air around 180° for example. In other words, the airstream 1501 may be sucked into the fuselage 100 by the air sucking unit 304, wherein the airstream 1501 is direction outside the fuselage 100 along a first direction (i .e. along a direction directed to a ground), wherein the air deflecting element 1502 deflects the sucked in airstream 1501 to a second direction, which differs to the first direction and which may be specifically antiparallel to the first direction .

Hence, if the aircraft stands onto the ground, the airstream is not sucked in directly from the vicinity of the ground such that less dust is sucked in if the aircraft is located (close) to the ground .

In a further exemplary embodiment the air deflecting element 1502 comprises variable and amendable air intakes, such that the air may be sucked in either along the first direction of the airstream 1501 or along the second direction of the airstream 1501'. Fig. 16 shows an exemplary embodiment of the aircraft, wherein the first wing arrangement 110 and the second wing arrangement 120 comprise a straight extension, the first wing arrangement 110 is shown on the left side in the fixed wing flight mode and on the right side in the hover flight mode. At its wing ends, the first wing arrangement comprises the nozzle sections 307.

The first wing arrangement 110 comprises a larger wingspan than the second wingspan of the second wing arrangement 120. Moreover, the first wing arrangement 110 comprises a larger lift area than the second wing

arrangement 120. The first wing arrangement 110 is arranged closer to the tail of the fuselage 100 than the second wing arrangement 120. Hence, if the aircraft stands with its tail 103 and e.g . a respective landing gear 201 (not shown) to the ground, the larger first wing arrangement is located also closer to the ground than the second wing arrangement 120. Side winds attack the aircraft more severe at location the more the location is spaced from the ground . Hence, if the lift area, e.g . of the second wing arrangement 120, is smaller at regions of the aircraft which are further spaced apart from the ground as shown in Fig . 16, the aircraft is more stable against side winds. Fig. 17 shows a top view of an aircraft according to an exemplary

embodiment of the present invention. The aircraft shown in Fig . 17 is similar to the aircraft shown in Fig. 8.

Fig. 17 shows an aircraft comprising an X-configuration of the first wing arrangement 110 and the second wing arrangement 120, wherein the first wing arrangement comprises a forward wing swept and the second wing arrangement 120 comprises a rearward wing swept.

Furthermore, as shown in Fig . 17, the exhaust flaps 107, 107' arranged at a surface of the fuselage 100. Hence, the hot exhaust gas may be guided through the exhaust flaps 107, 107' along a desired exhaust direction (either to the nose 102 or to the tail 103 of the aircraft). The exhaust flaps 107, 107' may also function as air intake flaps 107, 107' which cover an air intake through which air by the suction unit 304 (see Fig.3) is feedable. It should be noted that the term "comprising" does not exclude other elements or steps and "a" or "an" does not exclude a plurality. Also elements described in association with different embodiments may be combined . It should also be noted that reference signs in the claims should not be construed as limiting the scope of the claims.

List of reference signs:

100 fuselage 130 third wing arrangement

101 fuselage axis

102 nose 201 landing gear

103 tail

104 first fuselage part 301 inner ring

105 second fuselage part 302 outer ring

106 propulsion unit 303 tubing

107 exhaust flap 304 air suction unit

305 first wing spar

110 first wing arrangement 306 further first wing spar

111 first rotary wing axis 307 nozzle section

112 first wing

113 further first wing 1301 cockpit

114 extendible lift increasing system

115 first longitudinal wing axis 1501 air stream

1502 air deflecting element

120 second wing arrangement

121 second rotary wing axis Θ swept angle

122 second wing

123 further second wing

125 second longitudinal wing axis

Claims

C l a i m s

1. Aircraft, comprising

a fuselage (100) comprising a fuselage axis (101), and

a first wing arrangement (110) which is mounted to the fuselage (100) such that the first wing arrangement (110) is tiltable around a first rotary wing axis (111) of the first wing arrangement (110) and such that the first wing arrangement (110) is rotatable around the fuselage axis (101),

wherein the first wing arrangement (110) is adapted in such a way that, in a fixed-wing flight mode, the first wing arrangement (110) do not rotate around the fuselage axis (101),

wherein the first wing arrangement (110) is further adapted in such a way that, in a hover flight mode, the first wing arrangement (110) is tilted around the respective first rotary wing axis (111) with respect to its orientation in the fixed-wing flight mode and that the first wing arrangement (110) rotates around the fuselage axis (101), and

wherein the first wing arrangement (110) comprises an extendible lift increasing system (114) which is arranged to the first wing arrangement (110) for selectively amending a lift area of the first wing arrangement (110) in the fixed-wing flight mode and the hover flight mode.

2. Aircraft according to claim 1,

wherein the extendible lift increasing system (114) comprises an extendible flap arranged at a trailing edge of the first wing arrangement (110).

3. Aircraft according to claim 1 or 2,

wherein the extendible lift increasing system (114) comprises an extendible slat arranged at a leasing edge of the first wing arrangement (110).

4. Aircraft according to one of the claims 1 to 3,

wherein the first wing arrangement (110) is arranged to the fuselage (100) in the fixed-wing flight mode with a wing swept which is in particular a forward wing swept or a rearward wing swept.

5. Aircraft according to claim 4,

wherein the first wing arrangement (110) is arranged to the fuselage (100) such that the wing swept is adjustable.

6. Aircraft according to one of the claims 1 to 5, further comprising

second wing arrangement (120) which is mounted to the fuselage (100) spaced apart from the first wing arrangement (110) along the fuselage axis (101).

7. Aircraft according to claim 6,

wherein the first second wing arrangement (120) is adapted in such a way that, in a fixed-wing flight mode, the second wing arrangement (120) does not rotate around the fuselage axis (101),

wherein the second wing arrangement (120) is further adapted in such a way that, in a hover flight mode, the second wing arrangement (120) is tilted around the respective first rotary wing axis (111) with respect to its

orientation in the fixed-wing flight mode and that the second wing

arrangement (120) rotates around the fuselage axis (101).

8. Aircraft according to claim 7,

wherein, in the hover flight mode, the first wing arrangement (110) is rotatable in a first rotating direction and the second wing arrangement (120) is rotatable in a second rotating direction which differs to the first rotating direction.

9. Aircraft according to one of the claims 6 to 8,

wherein the first wing arrangement (110) comprises a first wingspan (II), wherein the second wing arrangement (120) comprises a second wingspan (12),

wherein in particular the first wingspan (I I) is longer than the second wingspan (12).

10. Aircraft according to one of the claims 6 to 9,

wherein the first wing arrangement (110) is mounted to the fuselage (100) at a first mounting location, and

wherein the second wing arrangement (120) is mounted to the fuselage (100) at a second mounting location,

wherein the first mounting location and the second mounting location are spaced apart with respect to each other along the fuselage axis (101).

11. Aircraft according to one of the claims 6 to 10,

wherein the second wing arrangement (120) is arranged to the fuselage (100) in the fixed-wing flight mode with a wing swept.

12. Aircraft according to claim 11,

wherein the second wing swept is a rearward wing swept.

13. Aircraft according to claim 11,

wherein the second wing swept is a forward wing swept.

14. Aircraft according to one of the claims 1 to 13,

wherein at least the first wing arrangement (110) a comprises a dihedral angle or an anhedral angle.

15. Aircraft according to one of the claims 1 to 14, further comprising

a propulsion unit which is arranged to the fuselage (101).

16. Aircraft according to one of the claims 1 to 15, further comprising an air distribution system arranged inside the fuselage (101) and inside at least the first wing arrangement (110),

wherein the air distribution system comprises an air suction unit for generating pressurized air and a tubing,

wherein the air suction unit is in particular mounted to the fuselage (100), and wherein the first wing arrangement (110) comprises at least one nozzle section for blowing out air such that thrust is generatable,

wherein the tubing couples the nozzle section to the air suction unit for guiding the pressurized air from the air suction unit to the nozzle section.

17. Aircraft according to claim 16,

wherein the air distribution system comprises an air distribution centrifuge, wherein the air distribution centrifuge comprises an inner ring and an outer ring which is rotatable relatively to the inner ring,

wherein the inner ring is mounted to the fuselage (100),

wherein the outer ring is mounted to the first wing arrangement (110), wherein the inner ring and the outer ring are arranged with respect to each other such that an air chamber is formed there between,

wherein the inner ring comprises an air inlet for injecting the pressurized air from the air suction unit into the air chamber, and

wherein the outer ring comprises an air outlet for exhausting the pressurized air from the air chamber to the nozzle sections.

18. Aircraft according to claim 16 or 17,

wherein the air distribution centrifuge comprises air guiding vanes which are installed inside the air chamber for guiding the pressurized air from the air inlet to the air outlet.

19. Aircraft according to one of the claims 1 to 18,

wherein the fuselage (100) comprises a first fuselage part (104) and a second fuselage part (105),

wherein the first fuselage part (104) and the second fuselage part (105) are arranged one after another along the fuselage axis (101), and

wherein the first wing arrangement (110) is mounted to the first fuselage part (104),

wherein the first fuselage part (104) is rotatable around the fuselage axis (101) with respect to the second fuselage part (105).

20. Aircraft according to one of the claims 1 to 19,

wherein the second fuselage part (105) comprises a landing gear (106), in particular an extendible landing gear.

21. Aircraft according to one of the claims 1 to 20,

wherein the first wing arrangement (110) comprises a first wing (112) and a further first wing (113),

wherein the first rotary wing axis (111) is split in a first rotary wing axis section and a further first rotary wing axis section,

wherein the first wing (112) extends along the first rotary wing axis section from the fuselage (100) and the further first wing (113) extends along the further first rotary wing axis section from the fuselage (100),

wherein the first wing (112) is tiltable with a first rotary direction around the first rotary wing axis section,

wherein the further first wing (113) is tiltable with a further first rotational direction around the further first rotary wing axis section, and

wherein in particular the first rotational direction differs to the further first rotational direction.

22. Aircraft according to one of the claims 1 to 21, further comprising a swash plate which is coupled to the fuselage (101),

wherein the first wing arrangement (110) and/or the second wing arrangement (120) are coupled to the swash plate,

wherein the swash plate is movable with respect to the fuselage axis (101) in a controllable manner, such that the orientation and the location of the respective first wing arrangement (110) and/or the second wing arrangement (120) with respect to the fuselage axis (101) is amendable.

23. Method of controlling an aircraft for vertical take-off and landing according to one of the claims 1 to 22, the method comprising

converting the aircraft in a fixed-wing flight mode by arranging the first wing arrangement (110) and the fuselage (100) with respect to each other such that the fixed-wing flight is enabled,

converting the aircraft in the hover flight mode

by tilting the first wing arrangement (110) around the first rotary wing axis (111), and

by rotating the first wing arrangement (110) around the fuselage axis (101) for enabling the hover flight,

extending or pulling in an extendible lift increasing system which is arranged to the first wing arrangement (110) for selectively amending a lift area of the first wing arrangement (110) in the fixed-wing flight mode and the hover flight mode.