Device for an aircraft for stopping at least one rotor of the aircraft rotating in a rotor circle, propulsion system and unmanned aircraft

Abstract

Device for an aircraft (501) for stopping at least one rotor (103) of the aircraft (501), in particular a drone rotor, rotating in a rotor circle (115), in the event of a collision of the aircraft (501) with an obstacle, wherein the at least one rotor (103) can be brought from a rotating state to a standstill state by means of a stopping device (102) in the event of a collision of the aircraft (501) with the obstacle, characterized in that the stopping device (102) has a catch device (123, 223) facing the at least one rotor (103) and a mechanically activatable release device (109, 231), wherein the mechanically activatable release device (109, 231) is operatively connected to the catch device (123, 223) and wherein the catch device (123, 223) is mechanically activated by the collision in the event of a collision of the aircraft (501) by means of the release device. (109,231) is moved into the respective rotor circle (115) and can be brought into engagement with at least one rotor (103), so that at least one rotor (103) is mechanically stopped by means of the catch device (123, 223).

Description

[0001] The invention relates to a device for an aircraft for stopping at least one rotor of the aircraft, in particular a drone rotor, rotating in a rotor circuit upon a collision of the aircraft with an obstacle. The at least one rotor can be converted from a rotating state to a stationary state by means of a stopping device upon a collision of the aircraft with the obstacle. Furthermore, the invention relates to a propulsion system for an unmanned aircraft having at least one rotor and such a device, as well as to an unmanned aircraft having a device or a propulsion system.

[0002] Aircraft, especially unmanned aerial vehicles (UAVs or AUS), such as drones, are often equipped with one or more rotors to generate lift and / or propulsion for their flight. It is not always possible to avoid a person coming into contact with a rotor, especially when interacting with people. Likewise, a collision with an object is sometimes unavoidable, for example, when using a drone to search for people in unfamiliar territory.

[0003] Common unmanned aircraft often only have conventional motor control available, for example, to bring the rotor(s) to a standstill. This would require complex sensor technology. Alternatively, drone rotors are enclosed in a rotor protection ring, which, however, only offers lateral protection. Interference along the rotor axis, thus injuring a person, is still possible.

[0004] DE 10 2019 135 246 B4 describes an aircraft and a method for intercepting a drone. The drone fires or throws threads into the rotor circuit of another drone to be intercepted, using the threads to prevent the drone from continuing its flight.

[0005] DE 10 2015 008 365 A1 discloses a defense drone which can prevent a drone to be intercepted from continuing its flight by means of hanging lines and possibly additional hooks, by inserting the lines into a rotor circuit of the drone to be intercepted while flying over the drone to be intercepted.

[0006] DE 10 2016 211 371 A1 discloses an interception device that is also suitable for intercepting drones. Using a firing device, an arrow with a net can be fired toward the drone.

[0007] WO 2018 / 112275 A1 discloses a net-shooting device that can also be used to intercept drones. It is also disclosed that the net-shooting device can be mounted on a drone in order to take action against a drone that is to be intercepted.

[0008] US 783 727 S, US 944 118 S and US 853 279 S each concern drones with protective devices around the respective rotors.

[0009] US 2017 / 0 259 914 A1 describes a drone with a folding mechanism, in which the respective support arms for the rotors are arranged so that they can be folded at an oblique spatial angle.

[0010] US 2019 / 0 367 166 A1 describes an autopilot for a drone, in which an operator can choose between a hover mode and a flight mode. A surrounding protective frame for the rotors contains sensors for operator contact.

[0011] JP 2019 - 123 419 A discloses a holding arrangement for securing the rotors of a drone. The holding arrangement serves to transport the drone with the rotors secured in the holding arrangement.

[0012] The object of the invention is to reduce the risk potential of an aircraft to objects and / or persons in the event of a collision with an obstacle.

[0013] The object is achieved by a device for an aircraft for stopping at least one rotor of the unmanned aircraft, in particular a drone rotor, rotating in a respective rotor circuit in the event of a collision of the aircraft with an obstacle, wherein the respective rotor can be transferred from a rotating state to a standstill state by means of a stopping device in the event of a collision of the aircraft with the obstacle, wherein the stopping device has a arresting device facing the respective rotor and a mechanically activatable triggering device, wherein the mechanically activatable triggering device is operatively connected to the arresting device and wherein the arresting device, in the event of a collision of the aircraft, is moved into the respective rotor circuit by means of the triggering device mechanically activated by the collision and can be brought into engagement with the respective rotor, such that the rotor is mechanically stopped by means of the arresting device.

[0014] Such an arresting device, together with the mechanically activated triggering device, can directly, immediately, and especially without electronic sensors, bring the rotor to a mechanical standstill within a partial revolution, at best, thus eliminating any further potential danger to objects and / or persons. Due to the mechanically active components, the device according to the invention is very simple in design and inexpensive to manufacture.

[0015] The following terms are explained in this context: In this context, a "stopping device" refers to any technical device capable of decelerating or completely stopping a "rotor," i.e., a rotating device capable of providing lift and / or propulsion and generating thrust, for example, through the angle of attack of a respective rotor blade, in such a way that it no longer poses any danger. "Stopping" in this context describes both the deceleration and the complete halting of the rotational movement of such a rotor. Deceleration must then be achieved at least to the extent that the remaining speed and the associated kinetic energy are below a damage limit. Such a rotor typically has one, two, or more of these so-called rotor blades, which rotate in a "rotor circle." The rotor circle describes the area swept by the rotor blades of the rotor while rotating.

[0016] An "aircraft" in this context is, for example, a drone, a helicopter, or another aircraft, such as a remote-controlled or self-navigating one. A drone is also known as an "unmanned aerial system" (UAS), "unmanned aerial vehicle" (UAV), or with multiple rotors as a "multicopter," as well as specifically according to the number of rotors, for example, a "quadrocopter" with four rotor blades, a "hexacopter" with six rotor blades, or an "octocopter" with eight rotor blades. It should be noted in this context that the invention is not limited to unmanned aircraft, but can be advantageously used particularly with such unmanned aircraft.The invention can also be used for manned aircraft, provided that the abrupt stopping of one of, for example, several rotors does not endanger flight safety or, for example, control means or safety devices are available which deactivate a corresponding device for necessary rotors if, for example, such a device has been triggered for an individual rotor.

[0017] In common parlance, such unmanned aerial vehicles are known as “drones,” which is why the rotor in the context of this invention can also be referred to as a “drone rotor.”

[0018] A "collision" with an obstacle refers, for example, to the aircraft approaching this obstacle and then making mechanical contact with it. Even minimal contact with the obstacle can be considered a collision. The decisive factor here is that in such a collision, for example, the rotor endangers the obstacle itself or a person. An "obstacle" in this context is any physical structure, such as an object or a person. It should be mentioned in this context that the triggering device can also have a trigger threshold, i.e. it is only triggered when a mechanical force acting on the obstacle is exceeded, and collisions below this trigger threshold are ignored.

[0019] A "stopping device" is the device or arrangement that can transition the rotor from a "rotating state," i.e., its typical, lift-generating motion, to a "standstill state." The standstill state, for example, represents a stationary rotor, but can also refer to a reduction in rotor speed to a level below a hazard threshold for, for example, a person.

[0020] A "safety device" refers, for example, to a mechanical device that engages with the rotor or with an individual rotor blade and is capable of mechanically bringing the rotor to a standstill. The safety device engages, for example, with the tip of a rotor blade and is attached to a fixed point so that the energy still present in the rotating rotor can be dissipated by the safety device. The safety device can remain undamaged after the rotor has stopped, or permanent damage can be tolerated.

[0021] A "mechanically activated triggering device" describes, for example, a sensing device directed toward the obstacle or a snap-action device triggered by contact with the obstacle, which then causes the safety gear to be moved into the rotor circuit through an operative connection with the triggering device. This then engages the safety gear with the rotor, stopping the rotor.

[0022] The "release device" is "operably connected" to the arresting device, meaning it is designed to mechanically act on the arresting device and move it into the respective rotor circuit. If the arresting device is then "engaged" with the rotor, the arresting device can act mechanically on the rotor and dissipate or dissipate its rotational energy, ultimately bringing the rotor to a standstill. It should be noted that the release device, for example, mechanically coupled with other arresting devices or arresting means for the respective rotors of the respective aircraft, can also cause several or all rotors to stop.For this purpose, for example, a pull cable or pull band guide and / or a hydraulic or pneumatic force transmission can be routed from the respective stopping device to several arresting devices of the respective rotors, so that when a respective triggering device is triggered, several or all arresting devices assigned to such an aircraft and a respective rotor are simultaneously engaged with the respective rotor. This can achieve a safe condition for all rotors. Furthermore, the control of a drone or UAS would attempt to compensate for the stop of only one of several existing rotors, thus causing an uncontrollable flight attitude.

[0023] The core idea of ​​the invention is, in particular, that the rotor or several rotors are brought to a standstill purely mechanically or primarily mechanically, in particular exclusively mechanically. While this involves a very robust and forceful deceleration of the respective rotor or several or all of them, it also ensures particularly safe and rapid deceleration of the rotor.

[0024] In order to integrate the stopping device within existing components, for example those present in a drone, the triggering device can be designed such that the triggering device has a rotor protection ring that is arranged such that it can move relative to the rotor circuit, in particular a flexible one, or is arranged or received on such a rotor protection ring. The arresting device is arranged on an inner side of the rotor protection ring facing the rotor circuit, and the rotor protection ring that is arranged such that it can move relative to the rotor circuit, in particular a flexible one, is moved or deformed in the direction of the rotor circuit by the collision. For example, thanks to the flexibility of the rotor protection ring, the triggering device can be designed as a single piece with the rotor protection ring without the need for additional components.The arresting device can then, for example, be attached to the inside of the rotor protection ring, so that the deformation of the rotor protection ring causes it to engage with the rotor circuit. If stopping all or several rotors of an aircraft is to be achieved, the arresting device can also be mechanically coupled to other arresting devices for other rotors in such a way that the engagement of one arresting device automatically causes all arresting devices to engage with the respective rotors.

[0025] A "rotor protection ring" describes, for example, a ring typically arranged around the rotor circuit and extending along a rotational axis of the rotor, which at least makes mechanical intervention in the rotor difficult. Such rotor protection rings are now common, for example, in autonomously or semi-autonomously flying drones, although in known drones they are usually rigid and stationary. Similar to a flexible rotor protection ring, the rotor protection ring itself can also be arranged so that it can move relative to, for example, the rotor axis, in particular by means of spring elements, so that moving the rotor protection ring relative to the axis and thus relative to the rotor circuit also causes the arresting device to engage.

[0026] In one embodiment, the catching device is arranged on a support structure facing the rotor circuit, in particular on a foam, wherein the catching device is in particular glued, sewn and / or stapled onto the support structure or the foam.

[0027] For example, a support structure that is not harmful to the rotor but provides mechanical support can be provided, which at least partially dissolves upon contact with the rotor circuit, i.e. with the rotating rotor, and releases the safety gear. In particular, a foam can be applied to the inside of a rotor protection ring, to which the safety gear is glued or sewn, or foamed into the foam, or glued between two foam strips. If the rotor protection ring is then displaced or deformed in the direction of the rotor circuit, the safety gear is brought into engagement with the respective rotor blade as the foam dissolves upon contact with the rotor blades, and can exert the braking and / or stopping effect.

[0028] To adapt the arresting system to different rotor blades and, for example, to provide a universal arresting system for different rotor blades, the arresting system features flexibly designed arresting elements. Such "arresting elements" include fibers, ropes, or straps, which are part of the arresting system and, in particular, engage with or become entangled around the rotor blades when the arresting system is deployed.

[0029] In one embodiment, the catching device has loop-shaped and / or ladder-shaped catching means.

[0030] Such loops or parts and / or arresting devices that are repeatedly formed along a longitudinal direction in the form of a ladder can become particularly easily caught with a corresponding rotor blade and thus cause the rotor to slow down very quickly.

[0031] Regardless of the embodiment, the device according to the invention can have a control unit that records a flight state of the aircraft using sensors, for example an altitude sensor or a position sensor. The control unit can then transfer the arresting device to an activated state in a first flight state, for example a takeoff or landing phase, and to a deactivated state in a second flight state, for example after reaching a specified flight altitude or reaching a specified distance from an operator, in particular a remote control location. This allows the arresting device to be used in a targeted manner in the activated state during corresponding critical flight states. The deactivated state can then be used to deactivate the arresting device in a targeted manner during flight phases in which, for example, there is a high risk of the aircraft falling freely.For this purpose, the control unit, for example, activates or deactivates the triggering device and / or couples and decouples the triggering device from the respective arresting device.

[0032] Additionally, particularly in the deactivated state of the device achieved by means of the control unit, or also as a respective independent embodiment, the triggering device can be assigned a particularly mechanical triggering means for triggering a safety device. The triggering means is activated, for example, simultaneously or with a time delay with the triggering device and thus activates the safety device. The safety device can be a parachute, a complete rescue system, or an airbag. The safety device is activated and thus ready for use, particularly in the deactivated state of the respective arresting device, for example in free flight. Likewise, the safety device can also be activated permanently and thus in addition to the respective arresting device.

[0033] To enable flexible use of the safety catch and, for example, to activate it only in specific situations, the safety catch is arranged in a guide system along a circumference of the rotor circle. The safety catch is arranged so that it can move along the guide system between a stowed position and an activated position. In the stowed position, it can be securely disengaged from the rotor and engaged with the rotor in the activated position. The stowed position can, for example, implement the deactivated state of the respective safety catch, and the activated position can implement the activated state of the respective safety catch, as described above.

[0034] For example, the safety catch is arranged to slide around a circumference of the rotor circuit, so that it can be moved like a curtain within the interior of the rotor circuit from the stowed position to the activated position. The "stowed position" is a position in which the safety catch is expressly not engageable with the rotor circuit. For example, the safety catch is hidden behind a protective device, such as a cover piece, in this position. The "activated position" describes a position analogous to the previously described examples, in which the safety catch is engageable with the rotor.

[0035] In one embodiment, the guide system is arranged, for example, in a sliding guide arranged on a circumference of the rotor circle, wherein the sliding guide is guided in particular on the inside of the rotor protection ring. Such a "sliding guide" can, for example, be a rail with corresponding sliders, in which, for example, the safety catch is arranged in a motor-driven manner.

[0036] To make the arresting device particularly robust and resilient, the arresting means are made of thermoplastic, thermosetting, and / or elastomeric material, and / or the arresting device or means comprise(s) an aramid and / or a polyamide, in particular aramid fibers and / or polyamide fibers. Other suitable fibers can be metallic, for example, steel fibers, or mineral, for example, glass fibers. Such fibers, which are known as synthetic fibers for ballistic applications, for example, exhibit not only high tensile strength but also acceptable extensibility, so that the force required to stop the rotor is at least partially absorbed and dampened by the elasticity of the fibers.

[0037] In a further aspect, the object is achieved by a drive system for an unmanned aircraft having a rotor for generating lift and / or propulsion and a device according to one of the previously described embodiments.

[0038] Such a drive system can, for example, be provided in the form of a drive set for drones fully equipped with a motor, a rotor and the device according to the invention, so that a safety system is provided which is inherently safe and not dependent on external sensors and which can be mounted on different drones.

[0039] In a further aspect, the object is achieved by an aircraft having a device according to one of the previously described embodiments or a drive system according to the previously described embodiment.

[0040] Such an aircraft is intrinsically safe without additional sensors and has, for example, several rotors which are equipped with the system according to the invention and / or the device according to the invention for stopping the rotor or also several or all rotors.

[0041] The invention will be explained in more detail below using exemplary embodiments. Fig. 1 a schematic representation of a drive for a drone with an emergency stop device in a side view, Fig. 2a a schematic representation of the emergency stop device of the Fig. 1, Fig. 2b a schematic representation of an alternative emergency stop device analogous to the emergency stop device of the Fig. 1, Fig. 3 a safety catch of the emergency stop device described above, Fig. 4 the drive of the Fig. 1 in a partially sectioned plan view, as well as Fig. 5 an unmanned aerial vehicle with an emergency stop device with several coupled arresting devices.

[0042] A drive 101, which is used, for example, for a drone, has an emergency stop device 102. Furthermore, a rotor 103 with several rotor blades 104 and a motor 105 in the drive 101 is provided for generating lift for the drone. For this purpose, the motor 105 and the rotor 103 are mounted on struts 107 within a protective ring 109. The protective ring is mounted on the struts 107 by means of springs 111, so that the protective ring 109 is arranged so as to be movable relative to an axis 106 of the rotor 103. Foam 121 is arranged on an inner side of the protective ring 109 and is applied as a thin coating to the protective ring 109. A catching device 123 is glued to the foam 121.

[0043] The catching device 123 has a catching line 125, which is designed as a loop 127 and has a plurality of catching webs 129 inside the loop, so that the catching device 123 is overall designed in a ladder shape from a flexible material, for example aramid yarn.

[0044] Each rotor blade 104 has a hook 141 at one end facing the protective ring 109, which is designed such that, during a rotational movement of the rotor along a direction of rotation 181, the capture device 123 can generally be picked up. However, this hook is not absolutely necessary for the intended use of the capture device, so that the rotor blades 104 can also be designed without such hooks 141. It should be noted that a single rotor blade or only a few or some rotor blades can be equipped with such a hook 141. If the drone, which has the drive 101, is now steered towards an obstacle, the protective ring 109 is moved in the direction of the rotor 103 by means of the springs 111. The capture device 123 thus enters a rotor circuit 115 in which the rotor 103 rotates.

[0045] The hook 141 of each rotor blade 104 then dips into the foam 121 and simultaneously engages the arresting device 123, so that, for example, the loop 127 or one of the arresting webs 129 decelerates the rotor blade 109 and brings it to a stop. In detail, this triggers the following sequence: If the rotor 103 approaches the arresting device 123 with a rotor blade 104 and touches it, the arresting device 123 is pulled along a short distance by the rotor 104. The arresting device 123 does not necessarily have to catch exactly on the rotor blade 104 that the arresting device 123 touches. By pulling the arresting device 123 along with the rotor blade 104, even if only a short distance, the diameter of an effective circle of the arresting device 123 is reduced and the respective arresting line 125 with the loop 127 and / or the arresting webs 127 are pulled into the rotor circle 115 of the rotor 103 and thus into the effective range of all other rotor blades 104.The effective radius of the arresting device 123 has thus become significantly smaller, and the loop 127 and / or the arresting webs 129 are thus pulled onto the rotor blades 104. The arresting webs 129 wrap around the rotor 103 and stop it.

[0046] An emergency stop device 202, whose function is analogous to the emergency stop device 102, has a holder 221, which is connected to a trigger 231 by means of a connector 232 through a protective ring 209. A catching device 223, similar to the catching device 123, is attached to the inside of the holder 221, for example by means of threads provided as a predetermined breaking point. If the drone now flies towards an obstacle, the trigger 231 is moved, for example against the force of a spring (not shown), in the direction of the respective rotor blade 104 of the rotor 103, thus engaging the catching device 223 with the rotor 103, similar to the previous example, so that the rotor 103 is brought to a stop at the respective rotor blade 104.

[0047] Furthermore, the emergency stop device 102 can also be modified (not shown) such that the safety catch 123 is accommodated in guide means, for example, sliding guides, on the protective ring 109 and can thus be guided around the protective ring 109. If a cover is then provided on a partial area of ​​the circumference of the protective ring 109, the safety catch 123 can be guided behind this cover and is thus deactivated. Only when the safety catch 123 is pulled out around the circumference, analogous to the previously described arrangement, can it fulfill its intended function.

[0048] A drone 501 is described as an example of a chained function of corresponding capture devices as follows: The drone 501 has a fuselage 503. A controller 505 is arranged centrally within the fuselage 503, which performs all control functions for the drone 501. Also arranged centrally within the fuselage 503 is an overall rescue system 507, which can deploy a parachute in an upward flight position and an air cushion in a downward flight position to cushion the impact of the drone 501 on the ground (neither described nor shown in detail).

[0049] Rotors 521, 523, 525, and 527 are arranged symmetrically on the fuselage 503 in rotor circles 511, 513, 515, and 517. During operation of the drone 501, the respective rotors rotate along a respective rotational direction 591, 593, 595, and 597.

[0050] At the respective corners of the fuselage 503, triggers 571, 573, 575, and 577 are assigned to a respective rotor and a respective rotor circuit. Upon contact with an obstacle, the respective triggers are pushed inward toward the respective rotor circuit and thereby act on a safety catch 541 for the rotors 521 and 527, as well as a safety catch 543 for the rotors 523 and 525 (see Fig. 5). The respective safety catches are designed to function according to the example above. Thus, if a safety catch engages a particular rotor, it can stop that particular rotor.

[0051] For this purpose, the drone 501 has channels 531, 533, 535, and 537 in its fuselage 503, through which the arresting devices 541 and 543 are mechanically connected to one another by pull cables or, alternatively, by hydraulic or pneumatic lines. If, for example, the arresting device 541 is brought into engagement with the rotor 521 by contact of the drone 501 at the trigger 571, this arresting device 541 is pulled along the direction of rotation 591 and pulls the arresting device 541 through the respective channels into the counter-rotating rotor 527, as well as the arresting device 543 into the counter-rotating rotors 523 and 525 via the cables guided through the channels 535 and 537. Thus, if a single trigger is triggered against any obstacle, all rotors of the drone 501 are forcibly stopped.

[0052] The controller 505 can further detect a triggering of the respective arresting device via sensors (not shown) and then, depending on a flight altitude detected by a further sensor (not shown), optionally trigger the parachute of the overall rescue system 507 to arrest a falling movement and / or the air cushion to cushion an impact on the ground. List of reference symbols 101 Drive 102 Emergency stop device 103 Rotor 104 rotor blade 105 engine 106 Axis 107 Strut 109 Protective ring 111 spring 115 Rotor circuit 121 foam 123 arresting device 125 fishing line 127 Loop 129 Fishing jetty 141 hooks 181 Direction of rotation 202 Emergency stop device 209 Protective ring 221 holders 223 arresting device 231 triggers 232 connectors 501 Drone 503 fuselage 505 Control 507 Total rescue system 511 rotor circuit 513 rotor circuit 515 rotor circuit 517 Rotor circuit 521 Rotor 523 Rotor 525 rotor 527 Rotor 531 channel 533 Channel 535 channel 537 Channel 541 arresting device 543 arresting device 571 triggers 573 triggers 575 triggers 577 triggers 591 Direction of rotation 593 Direction of rotation 595 Direction of rotation 597 Direction of rotation

Claims

[1] Device for an aircraft (501) for stopping at least one rotor (103) of the aircraft (501), in particular a drone rotor, rotating in a rotor circuit (115) in the event of a collision of the aircraft (501) with an obstacle, wherein the at least one rotor (103) can be transferred from a rotating state to a stationary state by means of a stopping device (102) in the event of a collision of the aircraft (501) with the obstacle, characterized byin that the stopping device (102) has a catching device (123, 223) facing the at least one rotor (103) and a mechanically activatable triggering device (109, 231), wherein the mechanically activatable triggering device (109, 231) is operatively connected to the catching device (123, 223) and wherein, in the event of a collision of the aircraft (501), the catching device (123, 223) is moved into the respective rotor circuit (115) by means of the triggering device (109, 231) mechanically activated by the collision and can be brought into engagement with the at least one rotor (103), so that the at least one rotor (103) is mechanically stopped by means of the catching device (123, 223). [2] Device according to claim 1, characterized byin that the triggering device (109, 231) has a rotor protection ring (109, 209) which is arranged to be movable relative to the rotor circuit (115), in particular a flexible rotor protection ring, wherein the catching device (123, 223) is arranged on an inner side of the rotor protection ring (109, 209) facing the rotor circuit (115), and the rotor protection ring (109, 209) which is arranged to be movable relative to the rotor circuit (115), in particular a flexible rotor protection ring, is movable, in particular deformable, in the direction of the rotor circuit (115) as a result of the collision. [3] Device according to claim 1 or 2, characterized by that the catching device (123, 223) is arranged on a support structure (121) facing the rotor circuit (115), in particular on a foam material (121), wherein the catching device (123, 223) is in particular glued, sewn and / or stapled onto the support structure (121). [4] Device according to one of the preceding claims, characterized bythat the catching device (123, 223) has catching means (125, 127, 129), in particular flexible catching means. [5] Device according to one of the preceding claims, characterized by that the catching device (123, 223) has loop-shaped (127) and / or ladder-shaped (129) arranged catching means (125, 127, 129). [6] Device according to one of the preceding claims, characterized by in that the catching device (123, 223) is arranged in a guide system along a circumference of the rotor circle, wherein the catching device (123, 223) is arranged to be movable along the guide system between a stowed position and an activated position and can be brought into engagement with the rotor (103) in a secured manner in the stowed position and into engagement with the rotor (103) in the activated position. [7] Device according to claim 6, characterized bythat the guide system has a sliding guide arranged on a circumference of the rotor circle (115), wherein the sliding guide is guided in particular on the inside of the rotor protection ring (109, 209). [8] Device according to one of the preceding claims, characterized by that the capture device (123, 223) comprises an aramid and / or a polyamide, in particular aramid fibers and / or polyamide fibers and / or polyethylene fibers, a fiber reinforcement, in particular with carbon fibers or glass fibers. [9] Device according to one of the preceding claims, characterized bythat the catching device (123, 223, 541) for one rotor (521, 527) is mechanically coupled to another catching device (543) or to other catching devices (543) for other rotors (523, 525), wherein by means of the mechanical coupling an engagement of one catching device (123, 223, 541) causes an engagement of another catching device (543), other catching devices (543) or all catching devices (543) with other rotors (523, 525) or all rotors (521, 523, 525, 527). [10] Device according to claim 9, characterized by that the arresting device (123, 223, 541) is coupled to the other arresting device (543) or to the other arresting devices (543) by means of a tension cord, in particular by means of a tension cable or by means of a tension band and / or hydraulically or pneumatically. [11] Propulsion system (101) for an aircraft (501) with at least one rotor (103) for generating lift and / or propulsion and a device according to one of the preceding claims. [12] Aircraft (501) with a device according to one of claims 1 to 10 or a propulsion system (101) according to claim 11.

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