ES2984545T3 - Hybrid propulsion system for a helicopter - Google Patents

Abstract

The invention relates to a hybrid propulsion system (4) comprising controllers (5, 7, 11) and a transmission shaft (3) of a helicopter having a main rotor (1) connected to a gearbox and capable of stably maintaining a flight attitude predefined by a pilot. The hybrid propulsion system comprises a pilot controller (5) as well as an internal combustion engine (VM) (6) and an electric motor (EM) (10) which are directly coupled with the transmission shaft (3). The internal combustion engine (6) is connected to an internal combustion engine controller (7), and the electric motor (10) is connected to an electric motor controller (11). According to the invention, a torque sensor (17) and a tachometer (18) are respectively located on the transmission shaft (3), wherein both the internal combustion engine controller (7) and the electric motor controller (11) can respectively receive values of the current rotation speed (DZ) and the current torque (DM) during operation. Predefined values of the rotational speed (DZ0) and the torque (DM0), with which the internal combustion engine (6) can increase its optimum performance, are stored and can be retrieved for the electric motor controller (11), and the former (DZ0) can also be retrieved for the internal combustion engine controller (7). A first directive is stored in the electric motor controller (11) to always apply a driving or braking force from the electric motor (10) to the drive shaft (3), said force being such that the internal combustion engine (6), when it has reached or maintains the optimum rotational speed (DZ0) on the drive shaft (3), automatically generates, on said drive shaft (3), the torque (DM0) with which it reaches the optimum engine power. The invention also relates to a corresponding method. (Automatic translation with Google Translate, without legal value)

Description

DESCRIPTION

Hybrid propulsion system for a helicopter

Technical field

The invention relates to a hybrid propulsion system with controllers and a drive shaft of a helicopter with a main rotor connected to a transmission, capable of stably maintaining a flight behavior predetermined by a pilot, comprising a pilot controller, a combustion engine (VE) and an electric motor (EM), both directly coupled to the drive shaft (3). The VE is connected to a VE control, which can regulate the supply of fuel from a fuel tank to the VE to provide a desired propulsion force on the drive shaft, and the EM to an EM controller, which by discharging a battery can operate the EM or charge the battery by a mechanical power applied to the EM, allowing the drive shaft to be driven or braked respectively. The invention also relates to a method for operating such a hybrid propulsion system.

State of the art

As in the automotive industry, propulsion with an additional electric motor is also known in helicopters, particularly with hybrid propulsion.

A similar system to the one described above is known from US 2017/0225573 A1. It includes a combustion engine and an electric motor which is arranged between the combustion engine and the main rotor transmission. The same is true of US 2018/0354635 A1. This also describes a method regulating the distribution between the combustion engine and the electric motor with various computer systems.

Another hybrid system is known from EP 3162713, which operates a helicopter by means of an electric motor and an internal combustion engine. The aim of the control described there is to absorb power peaks via the electric motor, so that the combustion engine is preferably operated in “steady state” mode, also known as “moving average power”. To achieve this, the control signal used is split into a high-frequency part and a low-frequency part, with the faster, high-frequency signal being sent to the electric motor, and the slower, low-frequency signal being sent to the combustion engine. Rapid changes are therefore taken over by the electric motor, while the combustion engine only has to make power changes in a gradual, so to speak “damped” manner. The disadvantage of this split is safety in the event of failure of one of the engines. Since neither engine receives the full signal, the remaining engine cannot automatically take over the flight requirements. An additional monitoring system is required to detect engine failure and immediately ensure that the remaining engine receives the full signal. Each additional control or monitoring system required again increases the risk to flight safety.

Presentation of the invention

The present invention aims to describe a hybrid propulsion system that ensures the safest possible operation of the helicopter. It is also a further object of the invention to provide a method according to which the operation can be carried out safely. This safe operation should also take place with minimum fuel consumption.

The tasks are solved by the features of the first claims of the respective categories. Other advantageous embodiments are described in the dependent claims.

According to the present invention, in a hybrid propulsion system mentioned above, at least one torque sensor and a tachometer are arranged on the drive shaft, where both the VM controller and the EM controller can receive in operation the current values of the rotational speed DZ and the current torque DM.

In addition, predefined values of the rotational speed DZo and the torque DMo are stored at which the VM reaches its optimum efficiency. These values are accessible from the EM controller, the first of these values, DZo, being also accessible by the VM controller.

The VM controller is autonomously able, by adapting the VM power, to constantly reach and maintain the predetermined DZo rate of turn on the driveshaft, thus maintaining stable any flight behavior predetermined by the pilot controller. In addition, the EM controller, by using the EM, can additionally boost or brake the driveshaft, which changes the DZ rate of turn and the V<m>controller automatically adjusts the power to the VM to again reach and maintain the predetermined DZo rate of turn on the driveshaft.

A first directive is stored in the EM controller to always exert a driving or braking force of the EM on the drive shaft, which causes the VM, when it has reached or maintains the optimum rotational speed DZo on the drive shaft, to automatically generate the torque DMo on the drive shaft, at which it reaches the optimum motor power.

Preferably, the EM is located between the VM and the main rotor transmission 1. The rotational speed DZ can be measured at any point on the drive shaft, being the same everywhere. At least one of the torque sensors must be located between the VM and the EM to determine the load of the VM on the drive shaft. More torque sensors can be placed between the EM and the transmission to determine the total load on the drive shaft. However, the torque sensor between the VM and the EM is essential for the EM controller, as it indicates the power at the VM, which according to the first directive must be operated with maximum efficiency.

A direct data signal line can be established between the pilot controller and the VM controller used for takeoff and landing of the helicopter. During these phases, the first directive is not applied. The indirect connection always exists through the helicopter's flight behavior: when the pilot adjusts the pitch of the rotor blades to gain altitude, the DZ rotation speed on the drive shaft immediately decreases due to the higher load, and then the power demand in normal operation is aligned with the first directive.

In addition, a level gauge in the fuel tank and a state-of-charge gauge in the battery can be arranged, which can transmit their measurement data in operation to the EM controller. Via a computing unit, the energies available at any given time can be calculated. If necessary, the EM controller can follow a second directive that differs from the first directive. This can be intended to protect the battery against over- and undercharging, to save fuel and/or to temporarily operate the MV at lower power in order to reduce emissions.

It is important that the VM controller with the VM is always autonomously able to reach the required DZ turn rate on the drive shaft at any time, in order to achieve or maintain a stable flight behaviour predetermined by the pilot controller. This means that a helicopter with its VM can be retrofitted with an EM and an EM controller in this way without the need to intervene in the existing VM controller system. This results in that in the event of a system failure, if the EM and/or the EM controller fail, the helicopter can normally only fly with the VM.

The method according to the present invention for operating a hybrid propulsion system for a helicopter driveshaft ensures a flight behavior requested by the pilot using a hybrid propulsion system according to the invention with controls. It performs the following steps:

The current values of the speed DZ and the torque value DM are continuously measured on the drive shaft and transmitted to both the EM controller and the VM controller. The preset values of the speed DZ0 and the torque DM0 are stored, with both values DZo, DMo being accessible from the EM controller and at least the speed DZo from the VM controller. Both controllers always detect deviations of the measured values DZ, DM from the preset values DZ0, DMo known to them.

Once a pilot generates a changed power demand on the driveshaft via the pilot controller to achieve a desired flight behavior, a change in the DZ turn rate on the driveshaft also occurs. Due to a deviation of the current DZ turn rate from the preset DZo turn rate, the VM controller adjusts the power on the VM in a stepwise manner so that the preset DZo turn rate is reached again.

The following example explains this in more detail:

The VM controller is set up so that the VM always applies load to reach and maintain constant the optimal DZo rate of turn. If the pilot adjusts the rotor blades to gain altitude, the DZ rate of turn decreases accordingly. The VM responds to this decrease in DZ rate of turn with an increase in power, which increases the torque applied by it. This in turn causes the DZ rate of turn to increase. Once this is again reached and maintained constant at the predefined DZo value, the VM controller has no further reason to change the engine power. The VM continues to operate unchanged, but now with a higher DM torque than before adjusting the rotor blades. When the helicopter descends, the opposite occurs, the torque applied by the VM decreases.

In the method according to the present invention with the hybrid drive system, however, the EM controller acts according to its first directive. Due to a deviation of the current values of the rotational speed DZ and/or the torque DM from the corresponding predefined values DZo, DMo, it adjusts the power in the EM more quickly than the VM so that, after the VM has regulated its power to the predefined rotational speed DZo, it applies the predefined torque DMo, thus reaching the optimum efficiency. The EM controller achieves this either by charging the battery via the mechanical power in the EM or by driving the EM via the load in the battery. In the example mentioned above, the EM controller comes into play. The predefined values of the rotational speed DZo and the torque DMo are known to it, and it can determine the respective differences to the current values DZ, dM based on the measurement data it receives.

The EM controller initially operates according to its first directive. Therefore, if the pilot adjusts the rotor blades to gain altitude, the rate of turn is initially reduced, as described above. However, before the VM increases its power by increasing the torque, the EM, which reacts considerably faster, takes on the additional load, so that the required rate of turn DZo is immediately reached again. The VM control, which also constantly monitors the rate of turn, only perceives a slight, temporary deviation from the specified rate of turn DZo, which was immediately compensated for by the EM, as it applied the necessary load immediately. Due to the slower response of the VM, it does not increase its power, but keeps the originally applied torque DM constant.

The same occurs during a descent, when the pilot reduces the pitch of the rotor blades. The EM battery is charged by the EM braking on the drive shaft, before the VM compensates for the increase in yaw rate and can reduce its power.

This first directive of the EM controller therefore regulates, on the one hand, the rotational speed DZ0 on the drive shaft and keeps it constant by appropriately controlling the EM. This prevents changes in the load of the <m>C; its torque remains constant. This is desirable as long as this torque matches the specified torque DM0. As long as this is the case, the efficiency will always be optimal.

In addition, the EM controller always checks whether the torque currently generated on the drive shaft by the VM matches the specified torque DMo. Deviations can occur, for example, after takeoff, during ascent or descent, or after the EM has been idle, such as when the battery charge state is too low.

Upon detecting a deviation in torque, the first directive of the EM controller also adjusts this measured torque DM to the specified value DMo as follows: If the measured torque is too high, the EM controller increases the rotational speed slightly. The VM controller responds with a power reduction, which causes the torque applied by the VM to decrease steadily. The EM controller maintains the slight increase in rotational speed until the measured torque DM matches the specified torque DM0. Once this is achieved, the EM power is rapidly reduced until the specified rotational speed DZo is reached again. As a result, the specified torque DMo is maintained. The VM now operates at its optimum efficiency, while the EM controller keeps the rotational speed constant so that the VM continues to operate at its optimum power.

Therefore, in operation, the EM controller increases power due to insufficient rotation speed, when DZ < DZo, and/or due to excessive torque, when DM > DMo, and vice versa.

According to the present invention, in case the EM controller is suspended due to the regulation of the yaw rate to the specified value DZo, the VM controller automatically ensures a stable flight behavior by providing the required power via the VM. This does not require additional adjustments or monitoring.

In a preferred method, the EM controller can, based on measurement data from a fuel tank level gauge and/or a battery state-of-charge gauge, determine the available energies and accordingly temporarily deviate from the first directive and proceed according to a second directive. In this second directive, the battery can be selectively charged or discharged in order to protect it, to save fuel or to temporarily operate the VM with lower power in order to reduce emissions. This can prevent, for example, deep discharge or overcharging of the battery. On the other hand, at high altitudes, the EM can be used more intensively in a selective manner, since fuel consumption increases considerably there. Furthermore, during the take-off and/or landing phase, exclusively the EM can be operated to reduce noise and exhaust emissions in the landing area, or exclusively the VM, as required.

While in EP 3162713 the pilot signal is split into a high frequency and a low frequency control signal to achieve a desired power distribution between two engines, in the present invention the power split in normal operation is controlled by the first directive of the EM controller, by adjusting the measured rate of turn DZ and the measured torque DM to the stored desired values DZo and DMo. During the normal flight phase, excluding take-off and landing, the controls of both engines receive no signals from the pilot controller. The EM and the VM adjust their powers to maintain the specified rate of turn DZo constant, with the faster responding EM compensating for any deviation before the slower VM can respond. Furthermore, according to the first directive, the EM adjusts the torque applied by the VM to the specified value DM0 by providing additional power, either positive or negative. Therefore, this hybrid propulsion system described here is very simple to control and safe in its process, even if the VM suddenly fails.

In this way, the hybrid propulsion system always operates with the load distribution that uses the available fuel most efficiently. However, this is not achieved by complicated calculations, but directly and solely through knowledge of the current values of rotational speed DZ and torque DM, and knowledge of their specified values DZo, DMo.

In case of EM failure, the hybrid propulsion system of the present invention becomes a conventional VM propulsion, since the VM controller provides, through the VM, the exactly required torque needed on the drive shaft with a defined delay, necessary to reach or maintain the flight behavior specified by the pilot.

In the event of a VM failure, the rate of turn decreases, which is immediately compensated by the EM by means of additional power. By keeping the DZ rate of turn constant, flight safety is ensured. In addition, the EM controller detects that the DM torque provided by the VM has disappeared, which can only mean that the VM is out of service. The EM therefore takes over the entire service provision until the VM is operational again or until landing. A safe flight is guaranteed at all times.

Since both controllers receive the same information, generated directly by the flight behaviour, each of the engines can autonomously guarantee the required flight behaviour. The load distribution between the two engines is carried out completely automatically, as the EM quickly recognises and executes its part of the work, allowing the VM to always operate in the optimal range. In addition, when fuel is scarce, the EM controller can load the EM more heavily to save fuel. To avoid deep discharge or overcharging of the battery, it can also deviate from the first directive. In addition, the EM can be activated as a booster to provide additional power, for example when flying over a high mountain. On the other hand, at extreme altitudes or in high temperatures, where the VM's power is considerably reduced due to thin air, the EM can be used more intensively if the battery charge allows it, in order to increase the available power limit or save fuel. During the take-off and/or landing phase, only the EM may be operated to reduce noise and exhaust emissions in the take-off and/or landing area.

Once an exceptional situation is resolved, the first directive is activated again.

Brief description of the drawings

The invention is explained below with reference to the drawings. They are shown:

1 Fig. 1 a schematic representation of a hybrid propulsion system according to the invention;

2 a graph to describe the load distribution in different flight behaviors, such as climb, cruise flight and descent.

Forms of carrying out the invention

Figure 1 shows a hybrid propulsion system 4 according to the invention in a more detailed version than would be necessary for the description of the invention. It shows a part of a helicopter with a drive train 3, a main rotor gearbox 1 and also a tail rotor 2, which is not relevant to the subject matter of the invention. A combustion engine (VE) 6 and an electric motor (EM) 10 are arranged in parallel in the drive train 3, the EM 10 preferably being located between the VE 6 and the main rotor gearbox 1. Other arrangements are also possible.

A pilot controller 5 is responsible for receiving control commands from a pilot to adjust the main rotor blades, which indirectly results in the required engine power as the necessary turn rate DZo on the drive train 3. An optional data signal line 19 from the pilot 5 to the VM controller 7 can be used for takeoff and landing maneuvers.

The VM 6 is connected to a fuel tank 8 and this in turn to the VM controller 7, which can regulate the fuel supply from the fuel tank 8 to the VM 6 to provide the necessary propulsion force in the drive train 3. Furthermore, the EM 10 is connected to a battery 14, preferably via a current converter 12 and a charging unit 13, which can be equipped with a current peak absorber. The EM 10 can be operated by charging the battery 14, or the battery 14 can be charged by the mechanical power in the EM 10, which causes the drive train 3 to be driven or braked respectively. An EM controller 11 is at least indirectly connected, for example via a current converter 12, to the EM 10 and can control it to provide a necessary propulsion or braking force in the drive train 3.

Furthermore, a level gauge 9 in the fuel tank 8 and a state-of-charge gauge 15 in the battery 14 may be arranged to transmit their measurement data in operation to a computing unit 16.

At least one torque sensor 17 and a tachometer 18 are located in the drive train 3. The VM controller 7 and the EM controller 11 receive data from at least one torque sensor 17 and a tachometer 18 in operation. The computing unit 16 is connected to the EM controller 11 and the VM controller 7. It is used to calculate the available power, the required torque in the drive train 3 and/or to control the EM controller 11. It includes a data memory 20, in which values of a predefined rotational speed DZo and a torque DMo are stored, these values being those that achieve an optimal power coupling of the VM 6, the efficiency of the VM being highest at these values.

In operation, it is the EM 11 controller that causes the load distribution in the VM 6 and EM 10. This is shown schematically in Figure 2.

The dashed curve in the upper diagram represents the flight behavior as a function of time, as required by the pilot controller 5 in each case, in particular the flight altitude H. The flight altitude "0" here refers to the ground. The solid line represents the effective flight altitude H, which is slightly delayed. In the first phase (I), the helicopter climbs steadily until it reaches the desired flight altitude Hi. In the second phase (II), it flies steadily at this height, and in the third phase (III), it descends again. Between all flight phases, a time elapses until the newly set target is reached.

The curves in the middle diagram schematically represent the total load PH, i.e. the total moment on the main rotor (dotted line), the PVM load on the VM 6 (dotted-dash line) and the PEM load on the EM 10 (dotted line). The lower diagram shows the rotational speed DZ.

After the start-up process, the VM 6 operates at a constantly high level. In the first phase I, the EM 10 functions as an additional booster once the VM 6 reaches the predefined optimal PVM load, by applying the torque DMo. It assists the VM (6) during the climb phase in phase I until the desired flight altitude Hi is reached, i.e. until the pilot slightly reduces the pitch angle of the rotor blades. The start-up process can deviate from the first directive until the helicopter is safely airborne.

By reducing the pitch of the rotor blades at the beginning of phase II, the DZ rate of turn briefly increases, as shown in the diagram below. The EM 10 responds immediately and reduces its power until the DZ rate of turn matches the DZ0 setting again. The flight altitude now remains constant throughout phase II. The VM 6 is sluggish and therefore does not respond to this temporary change. In the example shown, the load on the EM 10 in phase II is negative, so as a generator it discharges the additional energy available from the excess power of the VM 6 back into the battery 14. The VM 6 also does not change its load in phase II.

When starting the descent, at the beginning of phase III, the pilot again slightly reduces the pitch of the rotor blades, the DZ rate of turn is again temporarily increased, the EM 10 responds again by reducing its power. However, this time it regulates to a DZ rate of turn that is slightly higher than the DZo setting, in accordance with its second directive. Now, the energy in the EM 6 is recovered even more strongly, as the EM 10 further brakes the drive train 3. Since the DZ rate of turn has increased slightly, the VM 6 now responds, continuously reducing its power. In the meantime, the EM 10 maintains the elevated DZ rate of turn, as shown by the lowest curve in phase III: The solid line, which represents the current DZ rate of turn, is higher than the dotted line, which indicates DZo.

As long as the current DZ turn rate is higher than the predefined DZo turn rate, the power in the VM 6 and thus the noise and gas emissions at the landing site are reduced. This is achieved by constantly reducing the electrically generated power in the EM 10, which reduces its braking effect.

According to the present invention, the rotational speed DZ of the drive train 3, after the first directive, is regulated solely by the EM 10 to keep the DMo of the VM 6 constant at the prescribed rotational speed DZo. After the second directive, as shown in phase III, there is a deviation from this to specifically reduce the load on the VM 6. Apart from the already mentioned emission reduction, there may be other reasons for deviating from the first directive. Specifically, selective storage or discharge of the battery 14 when its state of charge requires it. In addition, the EM 10 may be connected as a booster to temporarily provide higher power or to save fuel, for example, at higher altitudes.

The second directive can be regulated, for example, based on knowledge of the energy reserves, if the EM 11 controller has information about the state of charge of the battery 14 and the fuel supply, by noise requirements depending on the flight altitude and/or through pre-specification of the flight path.

Reference List:

1. Transmission with main rotor

2. Tail rotor

3. Transmission shaft

4. Hybrid propulsion system

5. Pilot Controller

6. Combustion engine (ME)

7. VM Controller

8. Fuel tank

9. Level sensor

10. Electric motor (EM)

11. EM Controller

12. Power converter

13. Load unit

14. Battery

15. State of charge meter

16. Unit of calculation

17. Torque sensor

18. Tachometer

19. Data signal line

20. Data storage unit with the value of the optimal VM spin speed

I. First phase, promotion

II. Second phase, constant altitude

III. Third phase, descent

t. Time

H. Current altitude

Hi. Desired altitude

P. Power (redundant with torque)

PH. Total power

PEM. Power in the EM

PVM. Power in the VM

DZ. Rotational speed on the drive shaft, measured

DZo. Optimal turning speed

DM. Torque on the drive shaft, measured

DMo. Default pair

Claims (9)

1. Hybrid propulsion system (4) with controllers (5, 7, 11) and a transmission shaft (3) of a helicopter with a main rotor (1) connected to a gearbox, capable of stably maintaining a flight behavior predetermined by a pilot, comprising: - a pilot controller (5), - a combustion engine (VM) (6) and an electric motor (EM) (10), both directly connected to the drive shaft (3), - where the VM (6) is connected to a VM controller (7), which can regulate the supply of fuel from a fuel tank (8) to the VM (6) to provide a desired propulsion force on the drive shaft (3); - and where the EM (10) is connected to an EM controller (11), which by discharging a battery (14) can operate the EM (10) or charge the battery (14) by a mechanical power applied to the EM (10), which would drive or brake the drive shaft (3) in each case, - where on the drive shaft (3) there are one or more torque sensors (17) and tachometers (18), and both the Vm controller (7) and the EM controller (11) can receive values of the current speed (DZ) and the current torque (DM) in operation, - and where the predetermined values of speed (DZo) and torque (DMo), at which the VM (6) can reach its optimum efficiency, are stored and accessible to the EM controller (11), where the first (DZo) is also accessible to the VM controller (7), - and that the VM controller (7), by adjusting the power of the VM (6), can at all times autonomously reach and maintain constant the predetermined speed (DZo) on the transmission shaft (3) to maintain stable any flight behavior predetermined by the pilot controller (5), - where the EM controller (11), by using the EM (10), can additionally drive or brake the drive shaft (3), allowing the VM controller (7) to automatically adjust the power to the VM (6) based on the current speed (DZ) to reach or maintain the predetermined speed (DZo) on the drive shaft (3), characterized because - a first directive is stored in the EM controller (11) to always exert a propulsion or braking force of the EM (10) on the drive shaft (3), resulting in the VM (6), when it reaches or maintains the optimum speed (DZo) on the drive shaft (3), automatically generating the torque (DMo) on the drive shaft (3), at which it reaches the optimum engine power. 2. Hybrid propulsion system (4) according to claim 1, characterized in that the EM (10) is arranged between the VM (6) and the main rotor gearbox (1). 3. Hybrid propulsion system (4) according to claim 1 or 2, characterized in that a direct data signal line (19) is established between the pilot controller (5) and the VM controller (7), for starting and landing of the helicopter. 4. Hybrid propulsion system (4) according to any of the preceding claims, further characterized in that a level gauge (9) is provided in the fuel tank (8) and a state of charge gauge (15) is provided in the battery (14), which can transmit their measurement data in operation to the EM controller (11). 5. Hybrid propulsion system (4) according to claim 4, characterized by a calculation unit (16) for calculating the energies still available and, if necessary, for calculating a second directive differing from the first directive, in order to protect the battery against overcharging and over-discharging, to save fuel and/or to temporarily operate the VM (6) with lower power to reduce emissions. 6. Method for operating a hybrid propulsion system (4) for a transmission shaft (3) of a helicopter, to ensure a flight attitude required by the pilot, using a hybrid propulsion system (4) with controls (5, 7, 11) according to any of the preceding claims, characterized by the following steps: - continuously measure the current speed and torque values (DZ, DM) on the drive shaft (3) and transmit them to both the EM controller (11) and the VM controller (7), - storing predetermined values for speed (DZo) and torque (DMo), where both values (DZo, DMo) are accessible by the EM controller (11) and at least the speed (DZo) is accessible by the VM controller (7), and where these controllers (7, 11) always detect deviations between the measured values (DZ, DM) and the predetermined values (DZo, DMo), - When a pilot generates a variable power request on the driveshaft (3) via the pilot controller (5) to achieve a desired flight attitude, a change in speed (DZ) also occurs on the driveshaft (3). - that the VM controller (7), due to a deviation of the current speed (DZ) from the predetermined speed (DZo), adjusts the power in the VM (6) slowly so that the predetermined speed (DZo) is reached, - that the EM controller (11), according to its first directive, due to a deviation of the current speed (DZ) and/or torque (DM) values from the corresponding predetermined values (DZo, DMo), adjusts the power in the EM (10) more quickly than in the VM (6) so that the VM (6), by regulating its power to the predetermined speed (DZo) after a delay, generates the predetermined torque (DMo) thus reaching its optimum efficiency, - allowing the battery (14) to be charged using the mechanical energy of the EM (10) or to operate the EM (10) using the energy stored in the battery (14), - and that in case of failure of the EM controller (11), the VM controller (7), by regulating the speed until reaching the predetermined value (DZo), automatically provides the required power through the VM (7), thus ensuring a stable flight position. 7. The method according to Claim 6 using a hybrid propulsion system (4) according to Claim 5, characterized in that the EM controller (11), based on measurement data from a level gauge (9) of the fuel tank (8) and/or a state-of-charge gauge (15) of the battery (14), determines the remaining available energy and, accordingly, deviates from the regulation of the first directive according to a second directive to specifically charge or discharge the battery (14), thus protecting the battery, saving fuel or temporarily operating the VM (6) with lower power to reduce emissions. 8. The method according to any of Claims 6 or 7, characterized in that during the take-off and/or landing phase, only the EM (10) is operated to reduce noise and gas emissions in the landing area. 9. The method according to any of Claims 6 to 8, characterized in that the EM controller (11) increases the power in the E<m>(10) during operation based on insufficient speed (DZ < DZo) and/or excessive torque (DM > DMo), and vice versa.