engine failure training method on a hybrid-powered rotorcraft

Abstract

The present invention relates to a method for simulating an autorotation phase of a simulated rotorcraft (90). This method comprises a training phase carried out with a training rotorcraft (1) comprising a single training combustion engine (10) for rotating a training lift rotor (5). The training phase comprises an assignment by a regulator (45) to a regulation limit of a stored training value and a regulation of the training combustion engine (5) by the regulator (45) by maintaining the torque parameter of the training rotorcraft (1) less than or equal to the regulation limit, said training value being less than a nominal value so that the training combustion engine (10) develops a power equal to a reference power developed by a simulated electric motor (92). Abstract figure: figure 1

Description

Title of the invention: Engine failure training method on a hybrid-powered rotorcraft

[0001] The present invention relates to a method of training for engine failure on a hybrid-powered rotorcraft, and an aircraft applying this method.

[0002] A rotorcraft usually comprises a power plant for setting in motion at least one rotor participating in its lift. Such a rotor is referred to as a "lift rotor" for convenience hereinafter. For example, a helicopter may comprise a lift rotor and a tail rotor which participates in controlling the yaw movement of the aircraft.

[0003] The power plant may comprise at least one combustion engine. The expression "combustion engine" designates, for convenience, an engine requiring the combustion of a fuel to produce mechanical energy, such as a turbo-engine or a piston engine for example. The expression "combustion engine" is to be contrasted with the expression "electric motor" qualifying engines transforming electrical energy into mechanical energy.

[0004] In the event of a combustion engine failure on a conventional single-engine rotorcraft, the lift rotor is no longer driven by this combustion engine. The rotation of the lift rotor then undergoes a significant deceleration. The aircraft must then enter, under the control of its pilot, into an autorotation flight phase to limit the drop in the rotation speed of the lift rotor.

[0005] This entry into the autorotation flight phase must be made within a very short time, of the order of 1 to 2 seconds after the onset of the combustion engine failure in order to maintain an acceptable rotation speed of the lifting rotor. An autorotation flight phase corresponds to a particular flight phase in which the aircraft flies in descent without engine power.

[0006] On a helicopter of the type described above, the lift rotor is then rotated by the relative wind. The lift rotor remains the seat of sufficient stabilized lift to brake and control the descent of the aircraft until landing. To apply this particular piloting procedure, the pilot must enter the autorotation phase by rapidly lowering the collective pitch of the lift rotor blades to maintain a rotation speed of the lift rotor within permissible limits.

[0007] This particular procedure requires great precision and appropriate and recurring training on the part of the aircraft pilot. Such training is in fact difficult to implement. During such training, a pilot places the combustion engine in an idle speed to simulate engine failure, said engine then being driven at a minimum power insufficient to provide power to the rotor. The pilot operates, for example, a throttle handle to a mechanical idle stop, or controls an idle speed via a switch connected to the engine control box.

[0008] Solutions have been considered to assist the pilot of a single-engine rotorcraft by providing additional energy to carry out an autorotation flight phase.

[0009] Thus, document FR 2994687 describes an aircraft having a power transmission box moving at least one main lift rotor. According to this document, the operation of the combustion engine moving the power transmission box is monitored during a flight in order to detect a failure. When a failure of the combustion engine is detected, an electric motor is controlled to provide auxiliary power to the main lift rotor. This supply of auxiliary power then makes it possible to reduce the deceleration of the main lift rotor, which offers the pilot greater flexibility in the maneuver. Entering the aircraft into the autorotation flight phase is then faster and easier for the pilot.

[0010] Document FR 3 090 576 also describes a method for assisting a pilot of a single-engine rotary-wing aircraft during an autorotation flight phase, by using an electric motor.

[0011] The use of an auxiliary electric motor to facilitate the work of a pilot at the time of an engine failure in a single-engine rotorcraft is interesting. However, training a pilot for this autorotation phase can then be complicated. Indeed, only aircraft equipped with such an electric motor actually allow a pilot to be trained for the failure of the combustion engine on such a type of aircraft.

[0012] Furthermore, the electrical power sources of an aircraft of this type do not allow for numerous successive training sessions to be carried out during the same flight. The pilot must return to his base to recharge or change electric batteries in order to carry out several training sessions.

[0013] Documents relating to training for failure of a combustion engine on an aircraft comprising several combustion engines operating differently are far removed from this problem.

[0014] For example, document US 20230019379 describes combustion engine failure training on an aircraft with several different combustion engines. The aircraft has a main engine and a less powerful additional power unit. During training, the additional power unit provides a first power lower than the emergency power to be developed in case actual main engine failure, and the main engine is slowed down so that the sum of the power developed by the main engine and the power developed by the supplementary power unit equals the emergency power.

[0015] Patent application CN 115762292 describes a helicopter engine control system intended for training pilots in autorotation.

[0016] The present invention therefore aims to propose a method for training a pilot in the event of an engine failure which may occur on a single-engine rotorcraft having a rotary wing, this single-engine aircraft having an electric assistance motor capable of providing additional power to the rotary wing during the autorotation phase.

[0017] The invention thus aims at a method for simulating an autorotation phase that may occur on a simulated rotorcraft. The simulated rotorcraft comprises a single simulated combustion engine for rotating a simulated lift rotor in the absence of a failure and a simulated electric motor for rotating said simulated lift rotor during said autorotation phase.

[0018] The term "simulated" is associated with objects whose operation is to be simulated. The method therefore aims to simulate, with various types of rotorcraft, the operation of a rotorcraft called a "simulated rotorcraft" having a single combustion engine to rotate a lift rotor except in the event of a failure, and an electric motor to automatically provide engine torque to the lift rotor during an autorotation phase if necessary.

[0019] Conversely, the term "training" is associated with objects of a rotorcraft making it possible to simulate such behavior and on which the present method is applied. The training rotorcraft may be different or identical to the simulated rotorcraft.

[0020] This method then comprises a training phase carried out with a training rotorcraft, the training rotorcraft comprising a single training combustion engine for rotating a training lift rotor, the training combustion engine being regulated by a regulator of a piloting system by maintaining a torque parameter of the training rotorcraft less than or equal to a regulation limit, the training phase comprising:

[0021] - activation of the training phase by the operation of a human interface- input machine of the control system,

[0022] - in response to said activation, assignment by the regulator to the regulation limit of a stored drive value, and regulating the drive combustion engine by the regulator while maintaining the torque parameter of the drive rotorcraft less than or equal to the regulation limit, said drive value being less than a nominal value assigned to the regulation limit before said activation, so that the drive combustion engine develops a power equal to a reference power developed by the simulated electric motor during an autorotation phase within the simulated rotorcraft.

[0023] The term "assignment" means that the parameter concerned becomes equal to the value concerned.

[0024] As a result, this method does not involve an electric motor to simulate the desired behavior. According to this method, during the drive phase the regulator lowers the value of the regulation limit of the drive combustion engine by assigning it the predetermined drive value instead of the nominal value.

[0025] Therefore, the drive value being much lower than the nominal value, for example so that the combustion engine develops a power of the order of 20% of the power developed before the drive phase, the torque parameter becomes higher than the regulation limit. Consequently, the regulator closes the metering valve supplying fuel to the drive combustion engine. The power developed by the drive combustion engine will then decrease. The drive value is defined so that the drive combustion engine provides a power substantially equal to the reference power of the simulated electric motor. This reference power can be a maximum power for example.The term "power equal to a reference power" means that the driving combustion engine delivers power equal to the reference power of the simulated electric motor within a safety margin, for example plus or minus 10 percent.

[0026] As a result, the trainer rotorcraft actually behaves similarly to the simulated rotorcraft when the simulated combustion engine fails and the simulated electric motor takes over.

[0027] This method makes it possible to simulate in particular the initiation of an autorotation phase on such a simulated rotorcraft, without having to resort to an electric motor, or even on another type of rotorcraft. Thus, the training can be carried out multiple times successively during the same session without using an electric motor, surprisingly both with a conventional rotorcraft without such an electric motor and with a rotorcraft including autorotation assistance having such an electric motor.

[0028] The method may further comprise one or more of the following features, taken alone or in combination.

[0029] According to one possibility, the torque parameter may be an engine power or an engine torque transmitted to an element of the training rotorcraft.

[0030] For example, the torque parameter is measured on a shaft of the combustion engine. Thus, it is possible to determine, by calculations or tests or simulations for example, the value that the torque parameter must have to provide the drive lift rotor with substantially the same power as using the simulated electric motor.

[0031] According to a possibility compatible with the previous ones, the training rotorcraft may comprise an electric drive motor capable of rotating said training lift rotor and not used during the training phase or may comprise only the training combustion engine to set the training lift rotor in motion.

[0032] The training rotorcraft may be identical to the simulated rotorcraft. In this case, the electric motor does not need to be used to be simulated, which makes it possible to carry out the training phase several times during the same flight, without having to recharge the aircraft's electric batteries.

[0033] Alternatively, the training rotorcraft may be a conventional rotorcraft surprisingly capable of simulating entry into an autorotation phase within the simulated rotorcraft.

[0034] According to a possibility compatible with the previous ones, the regulation of the driving combustion engine can comprise a regulation of the driving combustion engine by applying a regulation law dedicated to the driving phase, and an inhibition of this regulation law as long as the torque parameter is greater than or equal to the driving value.

[0035] The regulator is configured to apply a control law in order to determine an order to be transmitted to the fuel meter. Outside the training phase, the control law takes the form of a usual nominal law. During the training phase, the nominal law is replaced by the dedicated regulation law. This dedicated regulation law may be of the type of the regulation law of the simulated electric motor. For example, the regulator applies the regulation law described in document FR 2 994 687 or document FR 3 090576.

[0036] According to a possibility compatible with the previous ones, the training rotorcraft can comprise an instrument of the piloting system displaying an operating limit determined by a display law as a function of the nominal value; the training phase comprising a replacement of the nominal value by the training value to determine the operating limit.

[0037] By way of illustration, the training rotorcraft includes a first limitation instrument also called "First Limitation Instrument" in English. This instrument considers several monitoring parameters and their limits. With regard to the torque parameter, this instrument then takes into consideration, during the training phase, the training value instead of the nominal value.

[0038] According to a possibility compatible with the previous ones, said regulation of said engine combustion engine may include maintaining a current power developed by the combustion engine greater than a power achieved at idle speed.

[0039] The drive combustion engine is thus not idled to simulate the operation of an electric assistance motor, for example by developing sufficient non-zero power to drive the rotor in rotation, unlike the procedure described previously applied to a conventional single-engine rotorcraft.

[0040] According to a possibility compatible with the preceding ones, the training phase may comprise a display of at least one of the following information: an indication of an action to be carried out on a collective pitch of blades of the drive lift rotor; a current rotation speed of said drive lift rotor; a rotation speed target of said drive lift rotor; a simulated state of charge, as a function of an operating time of the drive combustion engine and successive values ​​of the torque parameter during this operating time during the training phase, of a simulated electric battery electrically supplying the simulated electric motor; a symbol illustrating the implementation of the training phase.

[0041] According to a possibility compatible with the previous ones, the method can comprise an output from the training phase, said regulation limit being equal to the nominal value at the end of said output.

[0042] The exit represents a transition phase allowing the rotorcraft to be returned to the normal conditions present before the training phase.

[0043] According to a possibility compatible with the previous ones, the method may comprise a maneuver of a human-machine output interface of the control system, said output being carried out in response to said maneuver of the human-machine output interface.

[0044] A pilot can thus manually exit the training phase.

[0045] According to a possibility compatible with the previous ones, said output can be engaged automatically: - when a rotational speed of the training lift rotor is lower than a first speed threshold and at the same time a height of the training rotorcraft is higher than a height threshold, or - when the rotational speed of the training lift rotor is less than or equal to a second speed threshold and at the same time the height of the training rotorcraft is less than or equal to the height threshold, the first speed threshold being greater than the second speed threshold.

[0046] For example, the first speed threshold may be a predetermined threshold. The first speed threshold may also be entered in the aircraft flight manual for this procedure.

[0047] For example, the height threshold may be a predetermined threshold. For example, the height threshold is set to be greater than the height of a high point of the height-speed diagram of the aircraft. The height-speed diagram is a graph illustrating the safe and dangerous flight zones for a specific aircraft, and for example a helicopter. Said high point is the highest point associated with an area to be avoided.

[0048] For example, the second speed threshold may be of the order of 75% of a predetermined nominal speed.

[0049] Therefore, the control system can automatically exit the training phase depending on the rotational speed of the training lift rotor and the height of the training rotorcraft.

[0050] Indeed, when entering the autorotation flight phase, if the rotational speed of the drive lift rotor becomes lower than the first speed threshold, the pilot has not succeeded in entering this autorotation phase in the required manner. The drive phase must therefore be stopped so that the drive combustion engine provides sufficient power to rotate the drive lift rotor safely. Entry into the autorotation phase generally takes place at a height above the ground above the height threshold.

[0051] Conversely, just before landing, and therefore close to the ground, the pilot must increase the collective pitch of the blades of the training lift rotor in order to reduce the descent speed of the training rotorcraft. This action also has the effect of significantly reducing the rotation speed of the training lift rotor. However, this rotation speed of the training lift rotor must remain above the second speed threshold for the training lift rotor to provide sufficient lift. This landing phase takes place close to the ground, the height of the training rotorcraft relative to the ground being less than or equal to the height threshold.

[0052] Automatic mode and manual exit mode may be available on the same rotorcraft.

[0053] According to a possibility compatible with the previous ones, said output can comprise an allocation to the regulation limit of a value which increases according to a predetermined transition law from the drive value to the nominal value during a transition phase.

[0054] This feature makes it possible to gradually increase the regulation limit of the drive combustion engine, thus avoiding too abrupt a change in this regulation limit in order to preserve the mechanical transmission chain connecting the drive combustion engine to the drive lift rotor and / or not to disturb the pilot by a potential yaw jerk.

[0055] In addition to a method, the present invention relates to a computer program comprising instructions which, when said program is executed by a control system, cause said control system to implement this method.

[0056] The present invention also relates to a rotorcraft implementing this method. The present invention then relates to a training rotorcraft for training a pilot to enter an autorotation phase following an engine failure within a simulated rotorcraft, the training rotorcraft comprising a single drive combustion engine for rotating a training lift rotor. This training rotorcraft comprises a piloting system configured to implement this method.

[0057] The invention and its advantages will appear in more detail in the context of the description which follows with examples given for illustrative purposes with reference to the appended figures which represent:

[0058] [Fig.l], a schematic view showing a training rotorcraft capable of simulating the autorotation operation of a simulated rotorcraft, and

[0059] [Fig.2], a schematic view explaining the simulation method of the invention.

[0060] Elements present in several distinct figures are assigned a single reference.

[0061] The invention relates to a simulation method, as well as a computer program and a training rotorcraft capable of implementing this method.

[0062] According to [Fig.l] such a training rotorcraft 1 comprises at least one lift rotor, called training lift rotor 5. This training lift rotor 5 participates in particular in the lift of the training rotorcraft 1. For example, the training rotorcraft 1 is a helicopter.

[0063] The drive lift rotor 5 comprises at least one blade 6. In addition, the training rotorcraft 1 may comprise a pitch modification system for modifying on command the pitch of the blade(s) 6, in particular a collective pitch component for example. Such a pitch modification system may be of a conventional type and is not detailed so as not to unnecessarily weigh down [Fig.l]. Such a pitch modification system is known to those skilled in the art and may comprise, for example, a set of swashplates connected to each blade 6 by a pitch connecting rod.

[0064] In addition, the training rotorcraft 1 comprises a single combustion engine, called the driving combustion engine 10, for rotating the driving lift rotor 5. The driving combustion engine 10 comprises a power shaft 13.

[0065] According to the illustrated example, the drive combustion engine 10 may comprise a gas generator 11 followed by a power turbine 12 kinematically connected to the power shaft 13. Alternatively, the drive combustion engine 10 may include a piston engine.

[0066] Whatever the nature of the drive combustion engine 10, the power shaft 13 may be connected to a power transmission chain 8 which is connected to the drive lift rotor 5. For example, the power transmission chain 8 may in particular comprise a main power transmission box 80. The main power transmission box 80 may comprise a first input shaft 81 connected directly or indirectly to the power shaft 13, and / or a rotor mast 82 connected directly or indirectly to the drive lift rotor 5.

[0067] Optionally, the training rotorcraft 1 may comprise an electric drive motor 20 capable of participating punctually in the rotation of the drive lift rotor 5. Such an electric drive motor 20 may be, according to the example illustrated, connected to an input shaft of the power transmission box 80. Such an electric drive motor 20 is optional. The electric drive motor 20 may be an electric machine capable of operating in motor and electric generator modes or may operate solely in motor mode.

[0068] Furthermore, the training rotorcraft 1 is equipped with a piloting system 30 configured to allow the simulation of an autorotation phase which would take place on a simulated rotorcraft 90. The training rotorcraft 1 therefore allows the simulation of the behavior of a particular rotorcraft called "simulated rotorcraft 90" and represented in small in a bubble in broken lines for illustration. This simulated rotorcraft 90, the behavior of which is to be simulated with the training rotorcraft 1, comprises a single simulated combustion engine 91 for rotating a simulated lift rotor 93 except in the event of a failure and a simulated electric motor 92 for rotating said simulated lift rotor 93 during said autorotation phase. The performance of the simulated rotorcraft 90 is in fact known.

[0069] The control system 30 may in particular comprise a computer program 46 comprising instructions which, when the computer program 46 is executed, cause the control system 30 to implement the simulation method described below.

[0070] In particular, the control system 30 comprises a regulator 45. The regulator 45 may comprise one or more computers dedicated or not to this application and capable of applying said computer program 46. The term “computer” designates a unit which may comprise for example at least one processor and at least one memory, at least one integrated circuit, at least one programmable system, at least one logic circuit, these examples not limiting the scope given to the term “computer”. The term processor may designate both a central processing unit processing known by the acronym CPU, a graphics processing unit GPU, a digital unit known by the acronym DSP, a microcontroller...For example, the regulator 45 includes a calculator known by the expression "engine control unit" or "engine control unit" in English.

[0071] The regulator 45 can control a metering device 47 of the piloting system 30. The metering device 47 controls the fuel flow which supplies the drive combustion engine 10. For this purpose, the regulator 45 applies stored laws in order to transmit a control signal to the metering device 47 as a function of input data provided by usual sensors. For example, the regulator 45 communicates with a speed sensor 48 evaluating a current rotation speed NGCUR of the drive lift rotor 5 and / or a torque sensor 50 evaluating an engine torque developed by the drive combustion engine 10, and / or a height sensor 55 measuring a height of the drive rotorcraft 1 relative to an overflown surface. These sensors of the piloting system 30 are of a usual type known to those skilled in the art.For example, the height sensor includes a radiosonde, the torque sensor includes a torque meter, or even the speed sensor includes a position sensor and a derivator.

[0072] The regulator 45 can control the metering device 47 to make the rotation speed of the drive lift rotor 5 or of the power shaft 13 tend towards a speed setpoint for example.

[0073] In addition, the regulator 45 controls the metering device 47 so as not to exceed pre-established regulation limits of the drive combustion engine 10 or of the power transmission chain 8. The drive combustion engine 10 is thus regulated by the regulator 45 so that a torque parameter of the drive rotorcraft 1 is less than or equal to a regulation limit. The torque parameter is a driving power or an engine torque within an element of the drive rotorcraft 1, for example at the power shaft 13, the first input shaft 81, the rotor mast 82 or a cog of the power transmission box 80.

[0074] Furthermore, the regulator 45 can communicate with an instrument 70. Such an instrument 70 can be configured to display an operating limit 71 determined with a display law depending in particular on the regulation limit, or even other limits such as a temperature limit or rotation speed of the combustion engine. For example, this instrument 70 is of the type called IPL or First Limitation Instrument and displays a mark relative to an operating limit carrying the monitored parameter closest to its limit.

[0075] Furthermore, the regulator 45 can communicate with a display 75. This display 75 can comprise one or more screens making it possible to display one or more data described below.

[0076] Finally, the regulator 45 may be in wired or wireless communication with an input human-machine interface 31 and / or an output human-machine interface 32. These interfaces 31, 32 may constitute a single interface. For example, a two-position button represents the input human-machine interface 31 when the button is in a first position and the output human-machine interface 32 when the button is in a second position.

[0077] [Fig.2] illustrates the simulation method of the invention, this method being able to be implemented by the training rotorcraft 1 of [Fig.l] for example.

[0078] In flight, the regulator 45 controls the drive combustion engine 10, via the metering device 47, so that the drive lift rotor 5 rotates at a nominal rotational speed. The regulator 45 is configured to control the metering device 47 by applying a control law taking the form of a nominal law, and taking care that the torque parameter does not exceed the regulation limit. The regulation limit is then equal to a nominal value.

[0079] The method therefore comprises the activation STP1 of the PTRAIN training phase by operating the input human-machine interface 31. This input human-machine interface 31 transmits a signal, analog or digital, to the regulator 45. This signal carries an order to initiate the PTRAIN training phase.

[0080] In response to this activation STP1, the simulation method comprises an assignment STP2 of a stored drive value to the regulation limit. The regulator 45 is configured so that the regulation limit becomes equal to the drive value and no longer to the nominal value. The drive value is less than this nominal value.

[0081] The simulation method then comprises the STP3 regulation of the drive combustion engine 10 while maintaining the torque parameter of the drive rotorcraft 1 less than or equal to the new value of the regulation limit, namely the drive value.

[0082] The regulator 45 can in particular control the drive combustion engine 10 by placing it in a speed different from the idle speed, so as to develop a power greater than a power reached during an idle speed.

[0083] In particular, this regulation step STP3 of the drive combustion engine 10 may comprise a regulation STP32 of the drive combustion engine 10 by assigning to the control law no longer the nominal law, but a regulation law dedicated to the drive phase PTRAIN, and an inhibition STP33 of this dedicated regulation law as long as the torque parameter is greater than or equal to the drive value.

[0084] As long as the torque parameter is less than the drive value, the regulator 45 can use the dedicated regulation law to determine the position of the metering device 47 of fuel to be achieved. This dedicated regulation law may be similar or even identical to the law regulating the simulated electric motor 92. When the torque parameter is greater than or equal to the drive value, the regulator 45 may close the metering valve 47, with no fuel flow then supplying the drive combustion engine 10.

[0085] Thus, upon activation of the drive phase STP1, the regulation limit is suddenly significantly reduced. The torque parameter becomes greater than the regulation limit which is now equal to the drive value, which induces a closure of the fuel metering valve 47. The power developed by the drive combustion engine 10 suddenly drops, which induces a drop in the rotational speed of the drive lift rotor 5. When the torque parameter reaches the drive value, the drive combustion engine 10 is then regulated by the regulator 45 in a manner substantially equivalent to the simulated electric motor 92.

[0086] As a result, this method makes it possible to simulate the behavior of the simulated rotorcraft 90 with a training rotorcraft 1 which may or may not have an electric motor.

[0087] In parallel or subsequently, the method may, if necessary, include a STPR replacement of the nominal value by the drive value within the instrument 70. The simulation method then includes a STPC determination, with the instrument 70, of the operating limit using a new limit value for the torque parameter when applying the stored display law. During a STPAFF step, the method includes a display of the operating limit calculated by taking into account not the nominal value initially assigned to the torque parameter, but the drive value.

[0088] In parallel or subsequently, the method may, if necessary, include a STPINFO display of at least one item of information on the display 75.

[0089] Such information may be an ACT indication of action to be performed on a collective pitch of blades 6 of the drive lift rotor 5. For example, the regulator may transmit a signal to the display 75 to: request the display of a symbol indicating that the collective pitch must be increased if the current rotation speed of the drive lift rotor 5 is greater than a high threshold, of a symbol indicating that the collective pitch must be reduced if the current rotation speed of the drive lift rotor 5 is less than a low threshold, the low threshold being less than the high threshold, of a symbol indicating that the collective pitch must be maintained if the current rotation speed of the drive lift rotor is between the low threshold inclusive and the high threshold inclusive.

[0090] Such information may be a current rotation speed NRCUR of the drive lift rotor 5 measured with the speed sensor and transmitted di- directly or via regulator 45.

[0091] Such information may be an objective NR* of rotation speed of said drive lift rotor 5 established or stored by the regulator 45.

[0092] Such information may be a simulated state of charge 86 of a simulated electric battery 94, this state of charge 86 being calculated by the regulator 45 as a function of an operating time of the drive combustion engine 10 and the successive values ​​of the torque parameter during this operating time.

[0093] Such information can be illustrated by a TRAIN symbol signaling the implementation of the PTRAIN training phase, the input human-machine interface 31 or the regulator 45 transmitting to the display 75 an analog or digital signal carrying this information.

[0094] Furthermore, the method may comprise a test step for evaluating whether the training phase must be interrupted and whether a STPEXIT output of this training phase must be undertaken. Thus, the STPEXIT output of the training phase may be initiated by the regulator 45 in the presence of:

[0095] - of an STPCOM maneuver of the output human-machine interface 32, this output human-machine interface 32 sending a signal, analog or digital, to the regulator 45 carrying the required stop,

[0096] - when the regulator 45 determines (STPCOND1) that the rotation speed of the rotor of training lift 5 is lower than a first predetermined speed threshold, or even stored in the regulator 45, and that jointly a height of the training rotorcraft 1 is higher than a predetermined height threshold, or even stored in the regulator 45, or

[0097] - when the regulator 45 determines (STPCOND2) that the rotation speed of the rotor training lift 5 is less than a second speed threshold and that jointly the height of the training rotorcraft 1 is less than or equal to the height threshold, the first speed threshold being greater than the second speed threshold.

[0098] At the end of the output phase, the regulator 45 assigns to the regulation limit the nominal value at the end of a transition period and can apply the nominal law applied before the training phase.

[0099] On the other hand, during a transient period, the output step STPEXIT may comprise the assignment STPTRANS to the regulation limit of a value which increases according to a predetermined transition law from the drive value to the nominal value. The regulation law dedicated to the drive phase, the nominal regulation law used before or after the drive phase or another law may be applied by the regulator 45, while limiting the power developed by the drive combustion engine 10 by maintaining the torque parameter lower than or equal to the regulation limit.

[0100] Naturally, the present invention is subject to numerous variations. It is of course possible to replace a means described by an equivalent means without departing from the scope of the present invention and the claims.

Claims

Claims

1. Method for simulating an autorotation phase that may occur on a simulated rotorcraft (90) comprising a single simulated combustion engine (91) for rotating a simulated lift rotor (93) in the absence of a failure and a simulated electric motor (92) for rotating said simulated lift rotor (93) during said autorotation phase, characterized in that the method comprises a training phase (PTRAIN) carried out with a training rotorcraft (1), the training rotorcraft (1) comprising a single driving combustion engine (10) for rotating a driving lift rotor (5), the driving combustion engine (10) being regulated by a regulator (45) of a piloting system (30) by maintaining a torque parameter of the training rotorcraft (1) less than or equal to a regulation limit,the training phase (PTRAIN) comprising: - activation (STP1) of the training phase (PTRAIN) by the operation of an input human-machine interface (31) of the piloting system (30), - in response to said activation (STP1), assignment (STP2) by the regulator (45) to the regulation limit of a stored training value and regulation (STP3) of the training combustion engine by the regulator (45) by maintaining the torque parameter of the training rotorcraft (1) less than or equal to the regulation limit, said training value being less than a nominal value assigned to the regulation limit before said activation, so that the training combustion engine (10) develops a power equal to a reference power developed by the simulated electric motor (92) during an autorotation phase within the simulated rotorcraft (90).,

2. A method according to claim 1, characterized in that the torque parameter is a driving power or a motor torque transmitted to an element of the training rotorcraft.

3. Method according to any one of claims 1 to 2, characterized in that the training rotorcraft (1) comprises an electric drive motor (20) capable of rotating said training lift rotor (5) and not used during the training phase (PTRAIN) or comprises only the motor drive combustion (10) for driving the drive lift rotor (5).

4. Method according to any one of claims 1 to 3, characterized in that said regulation (STP3) of said drive combustion engine (10) comprises a regulation (STP32) of the drive combustion engine (10) by applying a regulation law dedicated to the drive phase (PTRAIN), and an inhibition (STP33) of this regulation law as long as the torque parameter is greater than or equal to the drive value.

5. Method according to any one of claims 1 to 4, characterized in that said training rotorcraft (1) comprises an instrument (70) of the piloting system (30) displaying an operating limit (71) determined, outside the training phase, by a display law as a function of the nominal value; the training phase (PTRAIN) comprising a replacement (STPR) of the nominal value by the training value to determine the operating limit.

6. Method according to any one of claims 1 to 5, characterized in that said regulation (STP3) of said drive combustion engine (10) comprises maintaining a current power developed by the drive combustion engine (10) greater than a power reached during an idling speed.

7. Method according to any one of claims 1 to 6, characterized in that the training phase (PTRAIN) comprises a display (STPINFO) of at least one of the following information: an indication (ACT) of an action to be carried out on a collective pitch of blades (6) of the drive lift rotor (5); a current rotation speed (NRCUR) of said drive lift rotor (5); a rotation speed target (NR*) of said drive lift rotor (5); a simulated state of charge (86), as a function of an operating time of the drive combustion engine (10) and successive values ​​of said torque parameter during said operating time during the training phase (PTRAIN), of a simulated electric battery (94) electrically supplying the simulated electric motor (92); a symbol (TRAIN) illustrating the implementation of the training phase (PTRAIN).

8. Method according to any one of claims 1 to 7, characterized in that the method comprises an output (STPEXIT) of the training phase (PTRAIN), said regulation limit being equal to the nominal value at the end of said output.

9. Method according to claim 8, characterized in that said method comprises a maneuver (STPCOM) of an output human-machine interface (32) of the control system, said output (STPEXIT) being carried out in response to said maneuver of the output human-machine interface.

10. Method according to any one of claims 8 to 9, characterized in that said output (STPEXIT) is automatically engaged: - when a rotational speed of the training lift rotor (5) is less than or equal to a first speed threshold and jointly a height of the training rotorcraft (1) is greater than a height threshold, or - when the rotational speed of the training lift rotor (5) is less than a second speed threshold and jointly the height of the training rotorcraft (1) is less than or equal to the height threshold, the first speed threshold being greater than the second speed threshold.

11. Method according to any one of claims 8 to 10, characterized in that said output (STPEXIT) comprises an assignment (STPTRANS) to the regulation limit of a value which increases according to a predetermined transition law from the drive value to the nominal value during a transition phase.

12. A computer program (46) comprising instructions which, when said program is executed by a control system (30), cause said control system (30) to implement the method according to any one of claims 1 to 11.

13. A training rotorcraft (1) for training a pilot to enter an autorotation phase following an engine failure within a simulated rotorcraft (90), the training rotorcraft (1) comprising a single drive combustion engine (10) for rotating a drive lift rotor (5), characterized in that said training rotorcraft (1) comprises a piloting system (30) configured to implement the method according to any one of claims 1 to 11.

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