WO2024141644A1

WO2024141644A1 - Aircraft

Info

Publication number: WO2024141644A1
Application number: PCT/EP2023/087989
Authority: WO
Inventors: Christoph Fraundorfer
Original assignee: Tensor AG
Priority date: 2022-12-30
Filing date: 2023-12-29
Publication date: 2024-07-04

Abstract

The invention relates to an aircraft, preferably a rotary-wing aircraft (1), in particular a gyrocopter, helicopter or multicopter, and/or a tilt-rotor convertiplane, having at least one rotor (2), which comprises at least two rotor blades (3, 4), and having at least one rotor head (15) which is rotatable about an axis of rotation (5) and, for accommodating the rotor blades (3, 4), has at least one rotor blade bearing (16), by means of which the rotor blades (3, 4) can flap about at least one flapping axis (17) such that a centre of gravity (20) of the rotor (2) remains in the region of the axis of rotation (5). According to the invention, the rotor blade bearing (16) is arranged outside the flapping axis (17).

Description

Aircraft

The present invention relates to an aircraft, preferably a rotary wing aircraft, in particular a gyroplane, helicopter or multicopter, and/or a tilt-rotor convertible aircraft, with at least one rotor comprising at least two rotor blades, and with at least one rotor head which can be rotated about an axis of rotation and which has at least one rotor blade bearing for receiving the rotor blades, by means of which the rotor blades can beat about at least one axis of rotation, so that a rotor center of gravity of the rotor remains in the region of the axis of rotation.

DE 20 2012 104 809 U1 discloses an aircraft with a rotor arranged on a rotor head. The rotor head comprises a rotor blade carrier, which in turn has a flapping joint around which the rotor blades of the rotor can flap.

The object of the present invention is to create a compact rotor head.

The problem is solved by an aircraft and a rotor head having the features of the independent patent claims.

An aircraft is proposed. The aircraft can be, for example, a rotary wing aircraft, which in turn can be a gyroplane, a helicopter or a multicopter. Additionally or alternatively, the aircraft can also be a tilt-rotor aircraft. The aircraft comprises at least one rotor, which comprises at least two rotor blades. The gyroplane and the helicopter as a rotary wing aircraft or as an aircraft comprise only one rotor in the most common designs. The helicopter also has more than two rotor blades in most designs. The multicopter has several rotors that are offset from one another. For example, the multicopter can have four rotors arranged in a square or a rectangle. However, the multicopter can also have more rotors. The rotors can additionally or alternatively be arranged one above the other or in at least two levels arranged one above the other. The multicopter can also be a drone or something similar to a drone, which are generally remote-controlled aircraft. In the aircraft or rotary-wing aircraft described here, the rotors or the rotor heads explained below are arranged in such a way that they are arranged in an upper region of the aircraft.

In the case of a tilt-rotor aircraft, the rotor and/or the rotor head explained below can also be designed to be pivotable. This means that the rotor can be adjusted for take-off and/or landing of the tilt-rotor aircraft so that it acts like a helicopter, for example. The rotor generates lift so that the tilt-rotor aircraft can take off and/or land vertically. After take-off, the rotor is pivoted forwards so that the rotor generates propulsion. The rotor then acts like a propeller. Before landing, the rotor can be pivoted upwards again so that it generates lift again and a vertical landing of the tilt-rotor aircraft is enabled.

The aircraft further comprises at least one rotor head that can be rotated about an axis of rotation and that has a rotor blade bearing for holding the rotor blades, by means of which the rotor blades can swing about at least one axis of rotation. The rotor can rock about the axis of rotation so that it can tilt in relation to the direction of flight during flight. This means that the center of gravity of the rotor remains in the area of the axis of rotation. The area can be 1 - 10 mm, for example. As a result, imbalances in the rotor are reduced when rotating, so that vibrations are reduced and flight behavior, flight stability and, above all, flight comfort are improved. Furthermore, the rotor blade bearing is arranged outside the flapping axis. This allows the rotor head to be made more compact. The rotor head is shortened as the rotor blade bearing is arranged outside the flapping axis.

It is advantageous if the flapping axis is at a distance from the rotor. In this case, the flapping axis can be at a distance from the rotor in the direction of the axis of rotation. Additionally or alternatively, the flapping axis can be at a distance from the rotor in a vertical direction of the aircraft. In this case, the flapping axis can also be at a distance from a region of a blade root of the respective rotor blade in the direction of the axis of rotation and/or in the vertical direction of the aircraft. The at least two rotor blades are connected to one another in the area of the two blade roots. A blade tip of the rotor blade is opposite the blade root. The blade tip is the outer end of the rotor blade and has the highest rotational speed when rotating. The blade root is an inner region of the rotor blade when it is arranged in the rotor.

It is advantageous if the flapping axis is arranged in the direction of the axis of rotation and/or in the vertical direction of the aircraft above the rotor blade bearing.

It is advantageous if the flapping axis is arranged above the rotor in the direction of the axis of rotation and/or in the vertical direction of the aircraft. Additionally or alternatively, it is advantageous if the rotor blade bearing is arranged at least partially below the rotor in the direction of the axis of rotation and/or in the vertical direction of the aircraft.

It is also advantageous if the impact axis is located in the area of the rotor's center of gravity. The range can be, for example, 1 - 10 mm. This means that the rotor's center of gravity moves when the blade is impacting. Rotor or rotor blades only move slightly away from the axis of impact or remain in the area of the axis of impact. As a result, the imbalances are reduced or only small imbalances are formed.

It is advantageous if the rotor blade bearing comprises at least two joint elements, in particular inclined towards one another, on which the rotor blades and/or the rotor are arranged. For example, the extension lines of the joint elements can intersect in the flapping axis, at least in a rest position of the rotor, i.e. when it is oriented parallel to the horizontal direction. Additionally or alternatively, the extension lines can intersect above the rotor blade bearing. Additionally or alternatively, the extension lines can intersect above the rotor. The joint elements can be designed as joint rods, for example. Additionally or alternatively, the joint elements can support the rotor blades and/or the rotor in a movable and/or articulated manner.

It is advantageous if the rotor head comprises a support element on which the rotor blade bearing is arranged. The at least two joint elements can also be arranged on the support element.

It is advantageous if the rotor blade bearing, in particular in the direction of the axis of rotation and/or in the vertical direction of the aircraft, is arranged between the carrier element and the rotor and/or rotor blades.

It is advantageous if the carrier element is a rotor disk. Alternatively, it is advantageous if the carrier element is arranged by means of a rotor shaft extension and/or at a rotor shaft end. The rotor shaft extension can also be arranged on the rotor disk. Furthermore, the rotor shaft extension and a rotor shaft of the rotor head can be formed as one piece. It is advantageous if the rotor extends around the rotor shaft extension, wherein the rotor preferably comprises a sleeve that extends around the rotor shaft extension and/or around the rotor shaft. Additionally or alternatively, at least connecting elements of the rotor for connecting the at least two rotor blades can extend around the rotor shaft extension and/or around the rotor shaft. This allows the rotor to be spaced apart from the rotor shaft extension so that the rotor can move relative to the rotor shaft extension and/or the rotor shaft when striking.

It is advantageous if the rotor is arranged above or below the support element in the direction of the axis of rotation and/or in the vertical direction of the aircraft.

It is advantageous if the joint elements are connected in an articulated, in particular rotatable, manner to the carrier element and rotatably to the rotor. This allows the joint elements to move when the rotor strikes.

It is advantageous if the joint elements are connected to the rotor, the rotor blades and/or the support element in an articulated manner by means of joints. The joints can be rotary and/or swivel joints. Additionally or alternatively, the joints can also be ball joints. The joint elements can thus rotate and/or swivel and/or be moved relative to the rotor, the rotor blades and/or the support element. The rotor or the rotor blades can therefore flap as a result.

Furthermore, a rotor head for an aircraft is proposed, wherein the aircraft has at least one feature of the preceding and/or following description. In addition, the rotor head comprises at least one feature of the preceding and/or following description. The use of a rotor head for an aircraft is also proposed, wherein the aircraft has at least one feature of the preceding and/or following description. In addition, the rotor head comprises at least one feature of the preceding and/or following description.

Further advantages of the invention are described in the following embodiments. They show:

Figure 1 is a schematic side view of a gyroplane as an aircraft,

Figure 2 is a schematic view of a rotor head with rotor blades and flapping axis,

Figure 3 is a schematic view of the rotor head and a rotor tilted around the beat axis,

Figure 4 is a schematic view of the rotor head with the rotor blade bearing outside the flapping axis,

Figure 5 is a schematic view of the rotor head, in which the rotor blade bearing is outside the flapping axis, with the flapping rotor,

Figure 6 is a schematic view of the rotor head in which the rotor blade bearing is outside the flapping axis and in which the rotor is below the rotor blade bearing, and

Figure 7 is a schematic view of the rotor head, where the rotor blade bearing is outside the flapping axis and where the Rotor is below the rotor blade bearing, with rotor flapping.

Figure 1 shows a side view of an aircraft 1. The aircraft 1 can be a gyroplane, a helicopter or a multicopter. The gyroplane shown here, as well as the helicopter or the multicopter, are rotary wing aircraft. In the present embodiment, a gyroplane is shown. The aircraft 1 comprises at least one rotor 2, which further comprises at least two rotor blades 3, 4. In the gyroplane shown here, the rotor 2 can be set in autorotation. The multicopter is characterized in that it comprises several rotors 2. In the multicopter as a rotary wing aircraft or aircraft 1, these several rotors 2 can be arranged next to one another in a surface and/or one above the other in at least two planes. The rotor 2 is also mounted on a mast 6 of the aircraft 1 so as to be rotatable about an axis of rotation 5. The fact that the rotor 2 of the gyroplane can be set into autorotation means that it is not driven by a drive of the gyroplane 1 during a normal flight phase. The rotor 2 is set into rotation during flight by a headwind flowing in from the front, namely autorotation. This means that, for example, a torque-compensating tail rotor can be dispensed with. In addition, the autorotation ensures a very high level of flight safety, since the rotor 2 is constantly in autorotation. In the case of helicopters and multicopters as rotary wing aircraft or as aircraft 1, the rotor 2 or the rotors 2 are driven as rotary wing aircraft or aircraft 1, in contrast to the gyroplane. Additionally or alternatively, the aircraft 1 can also be a tilt-rotor convertible aircraft in which at least one rotor 2 and/or the rotor head 15 described below can be pivoted. The tilt-rotor convertible aircraft can therefore fly as an airplane in one flight mode and resemble a helicopter in another flight mode.

In the tiltrotor aircraft, the rotor 2 can be used for takeoff and/or Landing can be swiveled upwards so that the tilt-rotor aircraft flies as a helicopter and can take off and/or land vertically. During the flight phase, the rotor 2 can be swiveled forwards or backwards so that the rotor 2 acts like the propeller 12 explained below.

The aircraft 1 further comprises a passenger cabin 7 in which a pilot and/or other persons can sit. Additionally or alternatively, the passenger cabin 7 can also comprise a cargo hold for cargo and/or a sensor area for sensors. The aircraft 1 further comprises wheels 8 and/or skids and/or floats so that the aircraft 1 can take off and land on water. In order to improve the lift of the aircraft 1, it can, as shown here, have wings 9 which are arranged on both sides of the aircraft 1 or on the passenger cabin 7. At least one strut 10 extends rearward from the passenger cabin 7 or from the wings 9. A tail unit 11 is arranged on the at least one strut 10 in order to improve the stability and/or steerability of the aircraft 1.

In order to achieve forward travel in the gyroplane as a rotary wing aircraft or aircraft 1, in the embodiment shown here, a propeller 12 is arranged in the rear area of the passenger cabin 7, which is driven by a drive not shown here. Additionally or alternatively, the propeller 12 can also be arranged in the front area and/or in the side area. It can be advantageous if a propeller 12 is arranged to the left and right of the passenger cabin 7, for example on the wings 9. The propeller 12 generates the forward travel and thus the airstream with which the rotor 2 is set into autorotation.

In the case of multicopters and helicopters, the propeller 12 and its associated drive are not required. In the case of helicopters, a torque-compensating tail rotor is also used if the helicopter is used as a Rotary wing aircraft or aircraft 1 only has one rotor 2. In the case of a multicopter as a rotary wing aircraft or aircraft 1, the propeller 12 can also be dispensed with. In addition, the torque-compensating tail rotor is not required in the case of a multicopter as a rotary wing aircraft or aircraft 1, since it has several rotors 2. The multicopter as a rotary wing aircraft or aircraft 1 can, for example, have four rotors 2 arranged in a square or a rectangle. However, the multicopter can also have more rotors 2 arranged flatly. Additionally or alternatively, at least some rotors 2 can also be arranged one above the other. The multicopter as a rotary wing aircraft or aircraft 1 can have the shape of a drone. In the case of a tilt-rotor convertible aircraft, the rotor 2 serves as a propeller 12 when it is pivoted in the direction of flight or forwards or backwards during the flight or cruise phase.

With the propeller 12, the air flows essentially evenly from the front onto the propeller 12. A propeller plane of the propeller 12 is essentially perpendicular to the incoming air flow or the direction of flight. With the rotor 2, on the other hand, a rotor plane of the rotor 2 is parallel to the incoming air flow or the direction of flight. As a result, the rotor blade 3, 4 rotating forwards has a higher incoming air speed than the rotor blade 3, 4 rotating backwards, since with the rotor blade 3, 4 rotating forwards the flight speed and the rotation speed are added together and with the rotor blade 3, 4 rotating backwards they are subtracted. With the rotor 2, the incoming air flow speeds and thus the lift generated change cyclically during one rotation. With the propeller 12, the propeller blades are constantly flowed against at the same incoming air speed.

Here, a longitudinal direction 13 and a vertical direction 14 of the aircraft 1 are also shown. The aircraft 1 can roll or sway around the longitudinal direction 13, or longitudinal axis. The longitudinal direction 13 can also be referred to as the roll axis. Around the vertical direction 14, or Vertical direction, vertical axis or yaw axis, the aircraft 1 can yaw or roll.

Features that have already been described in at least one previous figure cannot be explained again for the sake of simplicity. Furthermore, features can also only be described in this or in at least one of the subsequent figures. Furthermore, for the sake of simplicity, the same reference numerals are used for identical features. Furthermore, for the sake of clarity, not all features can be shown in the following figures and/or provided with a reference numeral. However, features shown in one or more of the previous figures can also be present in this or in one or more of the subsequent figures. Furthermore, for the sake of clarity, features can also only be shown in this or in one or more of the subsequent figures and/or provided with a reference numeral. Nevertheless, features that are only shown in one or more of the subsequent figures can also already be present in this or a previous figure.

Figure 2 shows a rotor head 15 with the rotor 2 of the aircraft 1. The aircraft 1 can have several rotor heads 15. As explained for example for the multicopter as a rotary wing aircraft or aircraft 1, this can have several rotors 2, which are each arranged on a rotor head 15.

The rotor head 15 comprises a rotor blade bearing 16, by means of which the rotor 2 is mounted. Furthermore, the rotor 2 can beat about a beating axis 17 by means of the rotor blade bearing 16. This means that the rotor 2 can rock about the beating axis 17. Figure 3 shows the rotor 2, which is tilted or beating about the beating axis 17. Figures 2 and 3 show the rotor head 2 of the prior art. When the rotor 2 rotates, one rotor blade 3, 4 will always rotate forwards in the direction of flight and the other rotor blade 3, 4 will rotate backwards in the direction of flight. The rotor blade 3, 4 running forwards generates a higher lift than the rotor blade 3, 4 running backwards, because with the rotor blade 3, 4 running forwards, the movement forwards and the airstream add up, whereas with the rotor blade 3, 4 running backwards, the movement backwards and the airstream subtract. Without the flapping, forces would act on the rotor head that would have to be absorbed. By flapping the rotor 2 around the flapping axis 17, these forces can be avoided. The rotor blade 3, 4 pivoted upwards in the figures, i.e. away from the aircraft 1, is the front rotor blade 3, 4 in the direction of flight of the aircraft 1. Accordingly, the rotor blade 3, 4 pivoted downwards in the figures, i.e. towards the aircraft 1, is the rear rotor blade 3, 4 in the direction of flight of the aircraft 1.

As can be seen here, the two rotor blades 3, 4 are not aligned with each other. Rather, they are inclined towards each other, which is advantageous for the flight behavior of the aircraft 1. However, this shifts a rotor center of gravity 20 to the outside of the rotor 2.

The rotor head 15 comprises a rotor blade carrier 22, on which a flapping joint block 21 is arranged. The rotor 2 with at least two rotor blades 3, 4 is arranged on the flapping joint block 21. The flapping axis 17, around which the rotor 2 can flap, runs through the flapping joint block 21. As can be seen here, the rotor 2 or the two rotor blades 3, 4 are arranged below the flapping axis 17. This principle is also called underhanging and has the advantage that the rotor center of gravity 20, which, as can be seen here, is formed from the two blade centers of gravity 18, 19, is arranged in the flapping axis 17. Since the flapping axis 17 is always arranged in the axis of rotation 5, this can prevent the rotor center of gravity 20 from shifting sideways when the rotor 2 flaps, so that the rotor center of gravity 20 no longer runs through the axis of rotation 5. Rather, even when the rotor 2 is beating, the rotor's center of gravity 20 runs along the axis of rotation 5, as can be seen in Figure 3. This prevents an imbalance when the rotor 2 is beating, which is advantageous for a smooth flight of the aircraft 1.

The rotor head 15 further comprises a carrier element 23 on which the rotor blade bearing 16 is arranged. The carrier element 23 can be, for example, a rotor disk 25. Furthermore, the rotor head 15 has a rotor shaft 24 which is rotatably arranged in a rotor head carrier 28. The rotor head 15 can thus rotate about the axis of rotation 5 relative to the rest of the aircraft 1, for example relative to the mast 6. The rotor head carrier 28 shown here can be rotated about a pitch axis 26 and a roll axis 27, so that the rotor head 15 and the rotor 2 can also be tilted about the pitch axis 26 and the roll axis 27. The rotation or tilting of the rotor head 15 and the rotor 2 about the pitch axis 26 and the roll axis 27 can be used in the aircraft 1 and in particular in the gyroplane to control the rotorcraft 1. For example, if the rotor 2 is rotated or tilted about the roll axis 27, the aircraft 1 can be flown to the left or right. If the rotor 2 is rotated or tilted forwards in the direction of flight about the pitch axis 26, the aircraft can be flown forwards or faster. If the rotor 2 is rotated or tilted backwards about the pitch axis 26, the aircraft can be flown backwards or slower.

Figure 2 also shows a first and a second cosine angle 43, 44. The rotor blades 3, 4 are each inclined upwards by the corresponding cosine angle 43, 44 relative to a horizontal in the resting state. The cosine angles 43, 44 are also equal to one another and lie in a range between 1° and 10°. The two rotor blades 3, 4 are therefore not aligned with one another, but enclose an angle of 180° minus twice a cosine angle 43, 44. The cosine angles are determined based on a Superposition of centrifugal force and lift force of the rotor blades 3, 4. The force resulting from these two forces acts along the rotor blade 3, 4, so that mainly tensile forces act on the rotor blade 3, 4.

Figure 4 shows the rotor head 15 according to the invention. Figure 5 shows the rotor head 15 of Figure 4, in which the rotor 2 beats. In this, the rotor blade bearing 16 is arranged outside the beat axis 17. This allows the rotor head 15 to be made compact. In particular, the rotor head 15 is shortened. The beat joint block 21, as shown in Figures 2 and 3, can be dispensed with. As can be seen here, the beat axis 17 is in the same place as in Figures 2 and 3, so that even with this rotor head 15 or the rotor blade bearing 16, the rotor center of gravity 20 remains in the axis of rotation 5 even when the rotor 2 beats.

It is advantageous if the rotor blade bearing 16, as shown here, comprises at least two joint elements 29, 30. These are inclined towards one another so that their extension lines 31, 32 intersect. The two extension lines 31, 32 intersect when the rotor 2 is in the rest position, i.e. when the rotor 2 is parallel to the longitudinal direction 13, in the rotation axis 5, in the impact axis 17 and/or in the rotor center of gravity 20. Additionally or alternatively, the two extension lines 31, 32 can also intersect in the vertical direction 14 above the rotor blade bearing 16 and/or in the vertical direction 14 above the rotor 2. In the present embodiment, in which the rotor 2 is not tilted or does not impact, the two extension lines 31, 32 of the two joint elements 29, 30 intersect in the impact axis 17 and/or in the rotor center of gravity 20.

The two joint elements 29, 30 are furthermore articulated and preferably connected at both joint element ends 33, 34 to the rotor 2 and/or the Support element 23. As a result, the two joint elements 29, 30 can rotate relative to the support element 23 and/or relative to the rotor 2. This can cause the rotor 2 to strike.

Furthermore, the rotor blade bearing 16 can comprise at least one joint 39 - 42, by means of which the joint elements 29, 30 are connected in an articulated manner to the rotor 2, the rotor blades 3, 4 and/or the carrier element 23. Here, each joint element 29, 30 has a joint 39 - 42 at the respective joint element ends 33, 34. The joint elements 39 - 42 can thereby rotate or pivot and thereby enable the rotor 2 or the rotor blades 3, 4 to beat, as shown in Figure 5. The joints 39 - 42 can be rotary and/or swivel joints and/or designed as ball joints.

Furthermore, the rotor blades 3, 4 can also be arranged with further swivel joints, not shown here, on the rotor head 15. These further swivel joints allow the rotor blades 3, 4 to swivel forwards or backwards when rotating in the rotor plane of the rotor 2 or in the direction of rotation, so that Coriolis forces are balanced when the rotor blades 3, 4 rotate.

Figure 5 shows the beating rotor 2, in which the rotor blade bearing 16 is arranged outside the beating axis 17. As is achieved with the help of the rotor blade bearing 16, the rotor center of gravity 20 remains in the rotation axis 5 or in the area of the rotation axis 5, so that as a result an imbalance of the rotor 2 is avoided when rotating. As can be seen here, compared to the arrangement and orientation of the two joint elements 29, 30 in Figure 4, the first joint element 29 has straightened up or it has turned away from the rotation axis 5 and/or from the vertical direction 14. Since a length of the two joint elements 29, 30 is constant, the beating rotor 2 has pulled the first joint element 29 upwards. In addition, the second joint element 30 was pulled downwards by the beating rotor 2, ie in the direction of the carrier element 23. This movement ensures that the rotor center of gravity 20 remains in the axis of rotation 5. In the embodiments of Figures 4 and 5, the rotor 2 rests on the rotor blade bearing 16. The pivoting of the joint elements 29, 30 is made possible here by the joints 39 - 42. The joint elements 29, 30 can be pivoted with the help of the joints 39 - 42 relative to the rotor 2, the rotor blades 3, 4 and/or the carrier element 23. The joint elements 29, 30 also connect the rotor 2 or the rotor blades 3, 4 to the carrier element 23.

It is advantageous if the joint elements 29, 30 are unchangeable in length or have a constant length.

Figure 6 shows a further embodiment in which the rotor blade bearing 16 is arranged outside the flapping axis 17. For the sake of simplicity, only the essential differences from the previous figures will be discussed here. Here, the rotor blade bearing 16 is arranged on the carrier element 23, with the rotor head 15 here having the rotor disk 25 in addition to the carrier element 23. The carrier element 23 is arranged here on a rotor shaft extension 35. The rotor shaft extension 35 is an extension of the rotor shaft 24. The rotor shaft extension 35 and the rotor shaft 24 can be formed as one piece with one another. Alternatively, the rotor shaft extension 35 can also be connected to the rotor shaft 24 and/or the rotor shaft extension 35 can be arranged on the rotor disk 25. By means of the rotor shaft extension 35, the carrier element 23 can be spaced apart from the rotor disk 25 and/or from the rotor head carrier 28. In this embodiment, the rotor 2 and/or the rotor blade bearing 16 hangs on the carrier element 23. Furthermore, the carrier element 23 and/or the rotor disk 25 can be formed in one piece with the rotor shaft extension 35.

The rotor blade bearing 16 again comprises the two joint elements 29, 30, which are articulated, by means of the joints 39 - 42, to the carrier element 23 and/or are connected to the rotor 2 or the rotor blades 3, 4, as already described in the previous figures. This allows the rotor 2 to beat about the beat axis 17, with the rotor's center of gravity 20 remaining in the rotation axis 5.

Furthermore, the rotor 2 extends in a section around the rotor shaft 24 or the rotor shaft extension 35. For this purpose, the rotor 2 shown here comprises a sleeve 36 which is arranged between the two rotor blades 3, 4. The sleeve comprises a passage 37 through which the rotor shaft 24 or the rotor shaft extension 35 extends through the sleeve 36. The passage 37 also has a larger diameter in the longitudinal direction 13 than the diameter of the rotor shaft 24 or the rotor shaft extension 35 in the longitudinal direction 13. This allows the rotor 2 or the sleeve 36 to move in the longitudinal direction 13 relative to the rotor shaft 24 or the rotor shaft extension 35 when the rotor 2 strikes. The sleeve 36 can be annular and/or connect the two rotor blades 3, 4 to one another. As an alternative to the sleeve 36, the rotor 2 can also have at least one connecting element that connects the two rotor blades 3, 4 to one another and that extends laterally past the rotor shaft 24 or the rotor shaft extension 35. The rotor 2 advantageously comprises two connecting elements that extend past the rotor shaft 24 or the rotor shaft extension 35 on both sides. This also allows the rotor 2 to beat.

The carrier element 23 is arranged here at a rotor shaft end 38. The rotor shaft end 38 can be formed by the rotor shaft 24 if the rotor shaft 24 extends to the carrier element 23 shown here or if the rotor shaft 24 is extended by the rotor shaft extension 35.

It should be noted here, as in Figure 7, that only the sleeve 36 is shown in section. Figure 7 shows the embodiment of Figure 6, in which the rotor 2 is striking. With the help of the passage 37 in the sleeve 36, as shown here, the rotor 2 can move in the longitudinal direction 13 relative to the rotor shaft 24 or the rotor shaft extension 35, so that the rotor 2 can strike. With

The design shown here can be used to limit the impact of the rotor 2, since at a certain deflection of the rotor 2 the sleeve 36 hits the rotor shaft 24 or the rotor shaft extension 35 and further deflection during impact is prevented. The joints 39 - 42 again enable the pivoting of the joint elements 29, 30 and thus the impact of the rotor 2 or the rotor blades 3, 4.

The present invention is not limited to the embodiments shown and described. Modifications within the scope of the patent claims are possible, as is a combination of the features, even if these are shown and described in different embodiments.

List of reference symbols

1 aircraft

2 Rotor

3 first rotor blade

4 second rotor blade

5 Rotation axis

6 Mast

7 person cabin

8 wheels

9 Wing

10 struts

11 Tail unit

12 propellers

13 Longitudinal direction

14 Vertical direction

15 Rotor head

16 Rotor blade bearing

17 Impact axis

18 first leaf center of gravity

19 second leaf center of gravity

20 Rotor center of gravity

21 Impact joint block

22 Rotor blade carrier

23 Support element

24 Rotor shaft

25 Rotor disc

26 Pitch axis

27 Roll axis

28 Rotor head carrier

29 first joint element

30 second joint element 31 first extension line

32 second extension line

33 first joint element end

34 second joint element end 35 rotor shaft extension

36 sleeve

37 Implementation

38 Rotor shaft end

39 first joint 40 second joint

41 third joint

42 fourth joint

43 first cosine angle

44 second cosine angle

Claims

Patent claims

1. Aircraft, preferably a rotary wing aircraft (1), in particular a gyroplane, helicopter or multicopter, and/or tilt-rotor convertible aircraft, with at least one rotor (2) which comprises at least two rotor blades (3, 4), and with at least one rotor head (15) which can be rotated about an axis of rotation (5) and which has at least one rotor blade bearing (16) for receiving the rotor blades (3, 4), by means of which the rotor blades (3, 4) can beat about at least one axis of rotation (17), so that a rotor center of gravity (20) of the rotor (2) remains in the region of the axis of rotation (5), characterized in that the rotor blade bearing (16) is arranged outside the axis of rotation (17).

2. Aircraft (1) according to the preceding claim, characterized in that the flapping axis (17), in particular in the direction of the axis of rotation (5), is spaced from the rotor (2), in particular from a region of a blade root of the respective rotor blade (3, 4).

3. Aircraft (1) according to one or more of the preceding claims, characterized in that the flapping axis (17) is arranged in the direction of the rotation axis (5) above the rotor blade bearing (16).

4. Aircraft (1) according to one or more of the preceding claims, characterized in that the flapping axis (17) is arranged above the rotor (2) in the direction of the rotation axis (5) and/or that the rotor bearing (16) is arranged at least partially below the rotor (2) in the direction of the rotation axis (5).

5. Aircraft (1) according to one or more of the preceding claims, characterized in that the flapping axis (17) is arranged in the region of the rotor center of gravity (20).

6. Aircraft (1) according to one or more of the preceding claims, characterized in that the rotor blade bearing (16) comprises at least two joint elements (29, 30), in particular inclined towards one another, on which the rotor blades (3, 4) are arranged.

7. Aircraft (1) according to one or more of the preceding claims, characterized in that the rotor head (15) comprises a support element (23) on which the rotor blade bearing (16), in particular the joint elements (29, 30), are arranged.

8. Aircraft (1) according to one or more of the preceding claims, characterized in that the rotor blade bearing (16) comprises joints (39 - 42) by means of which the joint elements (29, 30) are connected in an articulated manner to the rotor (2), the rotor blades (3, 4) and/or to the carrier element (23).

9. Aircraft (1) according to one or more of the preceding claims, characterized in that the rotor blade bearing (16), in particular in the direction of the axis of rotation (5), is arranged between the carrier element (23) and the rotor (2) and/or the rotor blades (3, 4).

10. Aircraft (1) according to one or more of the preceding claims, characterized in that the carrier element (23) is a rotor disk (25) or that the carrier element (23) is arranged on a rotor shaft extension (35) and/or on a rotor shaft end (38).

11. Aircraft (1) according to one or more of the preceding claims, characterized in that the rotor (2) extends around the rotor shaft extension (35), wherein the rotor (2) preferably comprises connecting elements for connecting the rotor blades (3, 4) and/or a sleeve (36) extending around the rotor shaft extension (35).

12. Aircraft (1) according to one or more of the preceding claims, characterized in that the rotor (2) in the vertical direction

(14) of the aircraft (1) is arranged above or below the support element (23).

13. Aircraft (1) according to one or more of the preceding claims, characterized in that the joint elements (29, 30) are connected in an articulated, in particular rotatable, manner to the carrier element (23) and to the rotor (2).

14. Rotor head (15) for an aircraft (1) according to one or more of the preceding claims, wherein the rotor head (15) preferably has at least one feature mentioned in the preceding claims and/or relating to the rotor head (15).

15. Use of a rotor head (15) for an aircraft (1) according to one or more of the preceding claims, wherein the rotor head

(15) preferably has at least one feature mentioned in the preceding claims and/or relating to the rotor head (15).