DE102020134583B4 - Protection of helicopters against dynamic rollover - Google Patents

Abstract

Method for protecting a helicopter (1) having a landing gear (9) during a lateral translational movement from a dynamic rollover induced by contact of the landing gear (9) with an obstacle (11) on the ground, wherein counter-torques are applied in order to counteract a detected development of the helicopter (1) towards the dynamic rollover, characterized in that in order to detect the development of the helicopter (1) towards the dynamic rollover, rolling moments about roll axes running in the region of the landing gear (9) are detected using acceleration sensors (13) distributed on the landing gear (9).

Description

TECHNICAL FIELD OF THE INVENTION

The invention relates to a method for protecting a helicopter during a lateral translational movement from a dynamic rollover induced by contact of the long frame with an obstacle on the ground. More specifically, the invention relates to a method having the features of the preamble of independent patent claim 1.

The invention further relates to a helicopter with a device for protecting the helicopter from a dynamic rollover induced by contact of the long frame with an obstacle on the ground. More specifically, the invention relates to a helicopter with the features of the preamble of independent patent claim 8.

Helicopters that perform a lateral translational movement, i.e. a sideways movement, when taking off, landing or hovering extremely low above the ground are susceptible to an accident scenario called dynamic rollover. Specifically, the risk of a dynamic rollover exists when the lateral translational movement of the helicopter results in unintentional contact with the ground and the helicopter's landing gear touches or gets caught on an obstacle on the ground. The obstacle induces a rolling movement that causes the helicopter to tip over. As soon as a certain roll angle is exceeded, the rotor blades of the helicopter's main rotor touch the ground, destroying them due to the rotational energy stored in them. A dynamic rollover often occurs when landing on unpaved landing sites. Here the helicopter kicks up dust or snow and deprives the pilot of a direct view of the ground. The pilot is therefore no longer able to correctly assess the movement of the helicopter relative to the ground, so that he actually performs unwanted and unobserved translational movements relative to the ground.

In free flight, a helicopter rolls around its center of mass. However, if the landing gear of the helicopter gets stuck at a certain point during the hovering phase, the roll axis immediately runs through the contact point of the landing gear. This changes the roll dynamics of the helicopter abruptly. Depending on the type of helicopter, the moment of inertia around the new roll axis is greatly increased. The control inputs must be increased accordingly and compensating control inputs are less effective than for the free-flying helicopter. This makes it difficult for the pilot to counteract any rolling motion that occurs. The entire process also takes place in an extremely short time, which is often less than the pilot's reaction time.

STATE OF THE ART

To protect pilots from a dynamic rollover during operational use, flight assistance systems are used to navigate a helicopter close to the ground and in poor visibility conditions. However, if the helicopter does move sideways and its landing gear comes into contact with the ground, these assistance systems are useless.

From the US 8 095 269 B2 A method for preventing a dynamic rollover is known. If it is detected based on monitored vehicle parameters that a dynamic rollover is imminent, thrust generators are activated to counteract the dynamic rollover. The thrust generators are arranged in the upper area of the vehicle and aligned to the side. The monitored vehicle parameters include a vehicle roll angle, which is monitored to determine whether it or its rate of change exceeds a permissible limit. The known method is not only applicable to a military off-road vehicle, but also to other vehicles, including aircraft and even a helicopter. Information on the specific implementation of the known method in a helicopter or the particular problems of dynamic rollover in a helicopter can be found in the US 8 095 269 B2 cannot be removed.

From the US 3 177 655 A A device for terminating and reversing the thrust of a rocket engine is known.

In order to compensate for the recoil of guns, e.g. hand-held anti-tank weapons, it is known to generate a counter-rotating recoil by ejecting an auxiliary mass in the opposite direction to the fired projectile. The auxiliary mass can be, for example, high-density salt water, which is ejected using an ignited ejection charge. An auxiliary mass in the form of a liquid is associated with a lower risk of injury than a solid auxiliary mass ejected to generate the counter-rotating recoil.

From the US 2020 / 0 047 916 A1 A landing gear for a helicopter with a plurality of force sensors is known. During landing, the force sensors detect forces on the landing gear at a plurality of positions. The force sensors are located on the underside of the landing gear and record the forces that occur when the vehicle comes into contact with the ground. By comparing the forces that occur and those recorded by the force sensors, the suitability of a surface for landing can be determined.

From the EN 10 2012 101 705 A1 A method is known for determining the actual center of gravity of a helicopter, in which support forces are measured at several measuring positions at which a landing gear of the helicopter is in contact with a support surface. The actual center of gravity of the helicopter is calculated depending on the support forces and the respective position of the helicopter for which the measurement of the support forces was carried out.

From the US 2006 / 0 283 239 A1 An onboard device for measuring the mass and position of the center of gravity of an aircraft is known. All parts of the aircraft's landing gear are equipped with force sensors. An additional device is arranged in the aircraft's fuselage to determine the aircraft's roll angle.

From the US 2010 / 0 095 788 A1 A sensor for determining the load on a landing gear of a helicopter is known. The sensor is arranged centrally on a cross-strut of the landing gear.

From the US 2018 / 0 229 857 A1 A method for determining a dynamic rollover condition in a helicopter is known. A dynamic rollover condition is detected in various ways, such as when a contact element is in contact with the ground while other contact elements are not in contact with the ground, and when the helicopter accidentally gets stuck on the ground during takeoff.

From the EN 10 2010 020 445 A1 A device for determining the ground contact of the landing gear of a helicopter is known. The device has at least one sensor designed to detect at least partial deformation of the landing gear. Each of two parallel skids of the landing gear is assigned a sensor so that the ground contact of each of the two skids can be determined.

TASK OF THE INVENTION

The invention is based on the object of demonstrating a method for protecting a helicopter against a dynamic rollover that is effective in practice and a corresponding helicopter.

SOLUTION

The object of the invention is achieved by a method having the features of independent patent claim 1 and by a helicopter having the features of independent patent claim 8. The dependent patent claims relate to preferred embodiments of the method according to the invention and of the helicopter according to the invention.

DESCRIPTION OF THE INVENTION

In a method according to the invention for protecting a helicopter having a landing gear during a lateral translational movement from a dynamic rollover induced by contact of the landing gear with an obstacle on the ground, in which counter-torques are applied in order to counteract a detected development of the helicopter towards the dynamic rollover, in order to detect the development of the helicopter towards the dynamic rollover, rolling torques about roll axes running in the area of the landing gear are recorded with acceleration sensors arranged distributed on the landing gear and, optionally, asymmetric forces exerted on the landing gear by the obstacle are recorded with force sensors arranged distributed on the landing gear.

In the method according to the invention, a dynamic rollover that is recognized as imminent is counteracted with suitable means, ie the emerging rolling movement of the helicopter is counteracted with counter-moments that are effective around the current roll axis. Suitable means for this are generally known to the person skilled in the art from the prior art, see e.g. the US 8 095 269 B2 and also the much earlier US$ 3,580,354 A.

In order to detect the development of the helicopter towards the dynamic rollover, the method according to the invention uses acceleration sensors distributed along the landing gear to detect rolling moments around roll axes running in the area of the landing gear and, optionally, force sensors distributed along the landing gear to detect asymmetrical forces exerted by the obstacle on the landing gear. These rolling moments are the torques acting in the rolling direction of the dynamic rollover, and the asymmetrical forces are the forces causing this. These forces result from the inertia of the helicopter, which is prevented from continuing its lateral translational movement without disruption by the obstacle.

If, in the method according to the invention for detecting whether dynamic rollover is imminent, sensors distributed on the landing gear sensors, this implies that the forces are recorded by the sensors at different points in such a way that it is at least recognized whether these forces are asymmetrically distributed. By “asymmetric” we mean that the forces are distributed asymmetrically in relation to a longitudinal center plane of the landing gear. Such asymmetric forces result in rolling moments that are capable of causing a dynamic rollover. If, for example, a helicopter with its landing gear gets caught on an obstacle on the ground during a lateral translational movement relative to the ground, transverse forces supported by the obstacle act on the landing gear. On one side of the landing gear, these forces are directed towards its longitudinal center plane and on the other side of the landing gear, away from the longitudinal center plane; overall, they are highly asymmetrical. These transverse forces result in rolling moments on the helicopter about a roll axis in the area of its landing gear, which runs where the helicopter got caught on the obstacle in question.

In order to detect pure transverse forces on the helicopter's landing gear, sensors distributed across the landing gear would not be required. Rather, a central force sensor or a few central force sensors would be sufficient. However, with several sensors distributed across the landing gear and a difference calculation or other comparison of the signals from these sensors, the accuracy of detecting the asymmetric forces on the landing gear can be increased and the roll axis of an impending dynamic rollover can be localized.

The rolling moments that result from a dynamic rollover of a helicopter that gets stuck on an obstacle on the ground during a translational lateral movement with its landing gear, around a roll axis that runs through the point of getting stuck, can best be recorded at a point on the landing gear that is as far away from the roll axis as possible. This is especially true if the resulting accelerations of the landing gear are recorded to record the rolling moments. Acceleration sensors that can be used for this purpose are typically much more sensitive than conventional force sensors, which typically record elastic deformation, e.g. elastic deformation of the landing gear, using strain gauges. With acceleration sensors, rolling moments that occur can also be recorded more easily in a direction-dependent manner. Conversely, acceleration sensors are often more expensive than force sensors. In a method according to the invention, the asymmetric forces can be recorded with force sensors and the rolling moments are recorded with acceleration and force sensors.

Preferably, the rolling moments and possibly the asymmetrical forces on the landing gear are detected in the method according to the invention with sensors which are distributed over at least 80% and preferably at least 90% of a lateral width of the landing gear in order to achieve maximum sensitivity for detecting rolling moments and asymmetrical forces occurring around any roll axes running in the area of the landing gear.

In the method according to the invention, the counter moments are sensibly applied on the one hand in such a way that the recorded roll moments are balanced out, and on the other hand until the landing gear is again aligned vertically with its longitudinal center plane or at least until the helicopter straightens up again around the respective roll axis running in the area of the landing gear. Applying the counter moments in such a way that the recorded roll moments are balanced out does not mean increasing the counter moments until they apply a counter moment that is just as large as the respective roll moment, but rather that all previous roll moments are balanced out by corresponding counter moments in order to stop the rolling movement of the helicopter. In addition, the rolling movement of the helicopter around the respective roll axis running in the area of the landing gear is to be reversed so that it straightens up again. This is completed when the landing gear is again aligned vertically with its longitudinal center plane at least to the extent that the pilot can catch the helicopter even with control inputs that are reduced in their effectiveness. With the control inputs reduced in their effectiveness because the helicopter no longer performs its rolling movements around its center of mass but around the contact point of its landing gear with the obstacle on the ground, rolling movements can often only be compensated up to a small angle of inclination of the helicopter with respect to the vertical, which is usually less than ten degrees.

Specifically, in the method according to the invention, a first angular integral of the recorded roll moments can be determined, and the counter moments can then be applied in such a way that a second angular integral of the counter moments about the respective roll axis running in the area of the landing gear is equal to the first angular integral. The equality of the angular integrals means that they are at least essentially or approximately identical. With identical angular integrals, the roll movement of the helicopter about the respective axis running in the area of the landing gear would rolling axis is stopped. A slightly larger second angle integral leads to a counter moment that rights the helicopter again.

In the method according to the invention, the counter-torques can be applied by means of thrust, e.g. by igniting a propellant charge, and/or by means of recoil, e.g. by ejecting an auxiliary mass with an ejection charge. Preferably, as can be seen from the above explanations, the counter-torques are applied in a precisely dosed manner in order to slow down the helicopter with regard to its rolling movement and to right it again, but not to set it into a rolling movement in the opposite direction. However, a dynamic rollover can also be prevented if the counter-torques miss this ideal target, but nevertheless essentially compensate for the rolling moments that have occurred. This can also be achieved with counter-torques that cannot be dosed. However, it is advantageous if, for example, the application of the counter-torques can be deliberately stopped when the recorded rolling moments are balanced out and the helicopter rightes itself again.

In order to apply the counter-torques as efficiently as possible, they should be applied as far away as possible from the respective roll axis running in the area of the landing gear. At this greatest possible distance, the exact direction of counter-forces to achieve a maximum counter-torque to the roll moments is less important than closer to the respective roll axis. Preferably, the counter-forces for applying the counter-torques in the method according to the invention are applied parallel to a rotor plane of the helicopter, specifically at a just sufficient vertical safety distance below the rotor plane on a cell of the helicopter. For this purpose, suitable devices for applying the counter-torques can be arranged in the upper area of the cell of the helicopter, the function of which does not collide with the main rotor of the helicopter, for example by gases or auxiliary masses emitted by the devices passing through the rotor plane, which would pose a risk of damage to the rotor blades of the main rotor.

In a helicopter according to the invention with a landing gear and with a device for protecting the helicopter during a lateral translational movement from a dynamic rollover induced by contact of the landing gear with an obstacle on the ground, wherein the device is designed to apply counter-torques in order to counteract a detected development of the helicopter towards the dynamic rollover, the device comprises acceleration sensors arranged in a distributed manner on the landing gear, and it is designed to use the acceleration sensors to detect rolling torques about roll axes running in the region of the landing gear in order to detect the development of the helicopter towards the dynamic rollover. In addition, the device can comprise force sensors arranged in a distributed manner on the landing gear and be designed to detect asymmetrical forces exerted by the obstacle on the landing gear in order to detect the development of the helicopter towards the dynamic rollover.

The sensors are preferably distributed over at least 80%, more preferably at least 90% of a lateral width of the landing gear. This means that at least two sensors are arranged on the landing gear at a distance of 80% or 90% of the lateral width of the landing gear.

The sensors of the device include acceleration sensors and, if necessary, force sensors. Preferably, the sensors record both the height and the direction of the respective acceleration or force. With regard to the direction, what matters is the components of the respective acceleration or force at the location of the sensor in the transverse and vertical directions, less in the longitudinal direction of the helicopter.

The device can have at least one propellant charge to apply the counter-moments by means of thrust. Typically, the device has at least two propellants in order to be able to apply the thrust in two opposing directions by igniting one of the two propellants. In principle, however, the direction in which thrust is generated can also be varied with just a single propellant charge. Alternatively or additionally, the device can have at least one auxiliary mass and an ejection set for ejecting the auxiliary mass to apply the counter-moments by means of recoil. Typically, in this case, too, there are at least two auxiliary masses and two ejection sets for ejecting the two auxiliary masses in opposite directions. The respective auxiliary mass preferably consists at least predominantly of salt water, so that the auxiliary mass has a high density on the one hand, but on the other hand, even if it is ejected at a relatively high speed, there is no risk of damage to parts of the helicopter or objects in its surroundings.

Generally speaking, devices for applying the counter-torques in the helicopter according to the invention are typical oriented parallel to a rotor plane of the helicopter, preferably at a vertical safety distance below the rotor plane. In this way, the counterforces for applying the counter moments are generated as far away as possible and with a correspondingly large lever around the respective roll axis in the area of the landing gear, so that high counter moments around this roll axis result.

The device according to the invention can also have several different propellant charges and/or different auxiliary masses and/or different ejection sets for ejecting the auxiliary masses, which can be used either individually or in combination to apply counter-moments of a desired size and for a desired duration.

Advantageous developments of the invention emerge from the patent claims, the description and the drawings.

The advantages of features and combinations of several features mentioned in the description are merely exemplary and can be used alternatively or cumulatively without the advantages necessarily having to be achieved by embodiments according to the invention.

The following applies to the disclosure content - not the scope of protection - of the original application documents and the patent: Further features can be found in the drawings - in particular the geometries shown and the relative dimensions of several components to one another as well as their relative arrangement and operative connection. The combination of features of different embodiments of the invention or of features of different patent claims is also possible in deviation from the selected references of the patent claims and is hereby suggested. This also applies to features that are shown in separate drawings or are mentioned in their description. These features can also be combined with features of different patent claims. Likewise, features listed in the patent claims can be omitted for further embodiments of the invention, but this does not apply to the independent patent claims of the granted patent.

The number of features mentioned in the patent claims and the description is to be understood as meaning that exactly this number or a greater number than the number mentioned is present, without the need for an explicit use of the adverb "at least". For example, if one discharge set is mentioned, this is to be understood as meaning that exactly one discharge set, two discharge sets or more discharge sets are present. The features mentioned in the patent claims can be supplemented by further features or can be the only features that the respective method or device has.

The reference signs contained in the patent claims do not represent a limitation of the scope of the subject matter protected by the patent claims. They serve only the purpose of making the patent claims easier to understand.

BRIEF DESCRIPTION OF THE CHARACTERS

• 1 zeigt einen sich lateral auf ein am Boden befindliches Hindernis hin bewegenden Hubschrauber.
• 2 zeigt die Auswirkungen des mit seinem Landegestell an dem Hindernis hängenbleibenden Hubschraubers auf an seinem Landegestell angeordnete Beschleunigungssensoren.
• 3 zeigt die Auswirkungen des mit seinem Landegestell an dem Hindernis hängenbleibenden Hubschraubers auf an seinem Landegestell angebrachte Kraftsensoren, die nicht unter die unabhängigen Patentansprüche fallen.
• 4 zeigt das Aufbringen von Gegenmomenten zu Rollmomenten um Rollachsen im Bereich des Landegestells beim Hängenbleiben des Hubschraubers gemäß 2 oder 3.
• 5 zeigt den wiederaufgerichteten Hubschrauber beim Beenden des Aufbringens der Gegenmomente und
• 6 illustriert schematisch eine Einrichtung zum Aufbringen der Gegenmomente mittels Rückstoß.

In the following, the invention is further explained and described with reference to preferred embodiments shown in the figures.

• 1 shows a helicopter moving laterally towards an obstacle on the ground.
• 2 shows the effects of the helicopter getting stuck on the obstacle with its landing gear on the acceleration sensors arranged on its landing gear.
• 3 shows the effects of the helicopter getting caught on the obstacle with its landing gear on force sensors attached to its landing gear, which are not covered by the independent patent claims.
• 4 shows the application of counter-torques to roll moments around roll axes in the area of the landing gear when the helicopter gets stuck according to 2 or 3 .
• 5 shows the re-erected helicopter finishing the application of the counter torques and
• 6 schematically illustrates a device for applying counter-moments by means of recoil.

FIGURE DESCRIPTION

A in 1 The helicopter 1 shown has a main rotor 3 driven about a rotor axis 2. The main rotor 3 rotates in a rotor plane 4, which runs at a distance above a cell 5 of the helicopter 1. In the rear area of the helicopter 1, a driven tail rotor 6 is provided at the end of a tail boom 7. A tail unit 8 is also located on the tail boom 7. To set the helicopter 1 down on the ground, a landing gear 9 is attached to the underside of the cell 5, which in the embodiment according to 1 wheels. When the helicopter 1 moves laterally close to the ground 10, If it hits an obstacle 11 from the side, particularly with its landing gear 9, there is a risk of a dynamic rollover. In a dynamic rollover, the helicopter 1 rolls around a roll axis running in the area of the landing gear 9, which accelerates due to a different moment of inertia than the normal roll axis of the helicopter 1 and can lead to contact of the main rotor 3 with the ground 10 and destruction of the main rotor 3 or the entire helicopter 1.

In order to detect the danger of such a dynamic rollover at an early stage, sensors 12 are arranged on the landing gear 9 of the helicopter 1 in order to detect rolling moments about roll axes that run in the area of the landing gear 9 and occur as a result of lateral impact with the obstacle 11.

2 explains the effects on sensors 12 designed here as acceleration sensors 13, if the one here in a different embodiment than in 1 Helicopter 1 shown with one side of its landing gear, which in the embodiment according to 2 skids on which obstacle 11 gets stuck. This results in a rolling moment about a roll axis 14 in the area of the stuck landing gear. The stuck part of the landing gear 9 and the sensor 12 arranged there are greatly accelerated against the previous lateral direction of movement of the helicopter 1. It then remains at rest. The sensor 12 on the opposite side of the landing gear 5 is initially also greatly accelerated against the previous lateral direction of movement of the helicopter 1. This is followed by an acceleration of this sensor 12 on the opposite side of the landing gear 5 in the direction of an arrow 15 running diagonally upwards, i.e. along a tangent to a circular path around the roll axis 14. With the help of the acceleration sensors 13, the rolling moment around the roll axis 14 occurring in the area of the landing gear 9 can be recorded and from this it can be concluded that there is a risk of an impending dynamic rollover.

According to 3 the sensors 12 are in the area of the landing gear 9, which is also in the embodiment of the helicopter 1 according to 3 Skids, force sensors 16 that respond to deformations of the landing gear 9 as a result of acting forces. Here, in particular, the sensor 12 on the side on which the landing gear 9 gets caught on the obstacle 11 indicates a high acting force with which the landing gear 9 rests on the obstacle 11. In contrast, the sensor 12 on the opposite side of the landing gear 9 only indicates a lower force as a result of the acceleration of the landing gear 9 about the roll axis 14. These strongly asymmetrical forces are also an indication of an impending dynamic rollover.

4 illustrates how, by generating recoil by ejecting an auxiliary mass 17, a counter-moment to the roll moment about the roll axis 14 is caused on the helicopter 1 in order to slow down the roll movement of the helicopter 1 about the roll axis 14 and, ideally, to compensate it exactly. In this ideal case, the helicopter 1 is in the position according to 4 with its rotor axis 2 or a in the view according to 5 the longitudinal center plane 18 of its landing gear 9, which here again has wheels, is aligned vertically again and is thus in a stable flight state. The auxiliary mass 17 is ejected away from the helicopter 1 on the side of the helicopter 1 on which the helicopter 1 hits the obstacle 11 in order to apply the counter-moment to the roll moment about the roll axis 14 in the correct direction. Devices 19 which eject the auxiliary mass 17 are arranged in the upper area of the cell 5 at a safety distance below the rotor plane 4, i.e. with practically the maximum vertical distance to the landing gear 9. The devices 19 eject the auxiliary mass 17 on the respective side of the helicopter 1 parallel to the rotor plane 4. Devices for applying counter-moments which counteract a recognized development of the helicopter 1 towards the dynamic rollover are in the 2 and 3 Although not shown, it is also present on the helicopters 1 there.

6 is a schematic diagram of such a device 19. It comprises an ejection set 20. In front of the ejection set 20, the auxiliary mass 17 is arranged in an ejection tube 21 under a cover 22. A partition 23 is provided between the ejection set 20 and the auxiliary mass 17. The ejection tube 21 is normally closed off from the outside by a cover flap 24, which opens automatically when the ejection set 20 is ignited and the auxiliary mass 17 is then ejected. The auxiliary mass 17 preferably consists of salt water. It is understood that the ejection set 20 is ignited with the aid of an igniter (not shown separately here) in order to eject the auxiliary mass 17. When the device 19, with the aid of the ejection set 20, ejects the auxiliary mass 17 at an average speed, so that the ejected auxiliary mass 17 has an impulse equal to the product of the average speed and its physical mass, this results in a recoil of the same magnitude on the helicopter 1, which is converted into a rotational energy or an angular integral of a counter-moment to the rolling movement of the helicopter. screwdriver 1 about the roll axis 14. If several devices 19 with different ejection sets 20 and/or different auxiliary masses 17 are present in the helicopter 1, the ejection set 20 or the combination of ejection sets 20 can be ignited which is or are best suited to providing such counter-moments as are required to terminate the rolling movement of the helicopter 1 resulting from the determined roll moments.

LIST OF REFERENCE SYMBOLS

1

helicopter

2

Rotor axis

3

Main rotor

4

Rotor level

5

cell

6

Tail rotor

7

Rear boom

8th

Tail unit

9

Landing gear

10

Floor

11

obstacle

12

sensor

13

Accelerometer

14

Roll axis

15

Arrow

16

Force sensor

17

Auxiliary mass

18

Longitudinal center plane of the landing gear 9

19

Furnishings

20

Ejection rate

21

Ejection pipe

22

cover

23

separation

24

Cover flap

Claims (12)

Method for protecting a helicopter (1) having a landing gear (9) during a lateral translational movement from a dynamic rollover induced by contact of the landing gear (9) with an obstacle (11) on the ground, wherein counter-torques are applied in order to counteract a detected development of the helicopter (1) towards the dynamic rollover, characterized in that in order to detect the development of the helicopter (1) towards the dynamic rollover, rolling moments about roll axes running in the region of the landing gear (9) are detected using acceleration sensors (13) distributed on the landing gear (9). Procedure according to Claim 1 , characterized in that the rolling moments are detected by acceleration sensors (13) which are distributed over at least 80% and preferably at least 90% of a lateral width of the landing gear (9). Method according to one of the preceding claims, characterized in that additionally asymmetric forces exerted by the obstacle (11) on the landing gear (9) are detected by force sensors (16) arranged distributed on the landing gear (9). Method according to one of the preceding claims, characterized in that - the counter moments are applied in such a way that the detected rolling moments are compensated, and - the counter moments are applied until - the helicopter (1) straightens up again about the respective rolling axis running in the region of the landing gear (9) or - the landing gear (9) is again aligned vertically with its longitudinal center plane. Method according to one of the preceding claims, characterized in that a first angular integral of the detected rolling moments is determined and that the counter-moments are applied such that a second angular integral of the counter-moments about the respective rolling axis running in the region of the landing gear (9) is equal to the first angular integral. Method according to one of the preceding claims, characterized in that the counter-moments are applied by means of thrust, preferably by igniting a propellant charge, and/or by means of recoil, preferably by ejecting an auxiliary mass with an ejection charge. Procedure according to Claim 6 , characterized in that the thrust and/or the recoil is applied parallel to a rotor plane (4) of the helicopter (1), preferably at a vertical safety distance below the rotor plane (4). Helicopter (1) with a landing gear (9) and with a device for protecting the helicopter (1) during a lateral translation movement Protection against a dynamic rollover induced by contact of the landing gear (9) with an obstacle (11) on the ground, wherein the device is designed to apply counter-torques in order to counteract a detected development of the helicopter (1) towards the dynamic rollover, characterized in that the device comprises acceleration sensors (13) arranged distributed on the landing gear (9) and is designed to use the acceleration sensors (13) to detect roll moments about roll axes running in the region of the landing gear (9) in order to detect the development of the helicopter (1) towards the dynamic rollover. Helicopter (1) to Claim 8 , characterized in that the acceleration sensors (13) are distributed over at least 80% and preferably at least 90% of a lateral width of the landing gear (9). Helicopter (1) to Claim 8 or 9 , characterized in that the device comprises force sensors (16) distributed on the landing gear (9) and is additionally designed to detect with the force sensors (16) asymmetric forces exerted by the obstacle (11) on the landing gear (9) in order to detect the development of the helicopter (1) towards the dynamic rollover. Helicopter (1) after one of the Claims 8 until 10 , characterized in that the device has at least one propellant charge for applying the counter-moments by means of thrust and/or at least one auxiliary mass and an ejection charge for ejecting the auxiliary mass for applying the counter-moments by means of recoil, wherein the auxiliary mass preferably consists at least predominantly of salt water. Helicopter (1) to Claim 11 , characterized in that the device for applying the counter-torques is designed and arranged such that it generates the thrust and/or recoil parallel to a rotor plane (4) of the helicopter (1), preferably at a vertical safety distance below the rotor plane (4).

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