Turboprop capable of providing an emergency wind turbine function and aircraft comprising such a turboprop

Abstract

The invention relates to a turboprop (10) comprising a propeller (12), a propeller shaft (13) carrying the propeller (12), the propeller (12) being a variable-pitch propeller having a propeller pitch, a rotating electrical machine (19), having at least a first configuration in which it is mechanically coupled to the propeller shaft (13), and at least one oil pump (21, 21B) configured to supply a hydraulic circuit for adjusting the pitch of the propeller (12). The oil pump is configured to be electrically driven. The invention further relates to an aircraft comprising such a turboprop (10) and the methods for controlling such a turboprop (10) and such an aircraft. Figure for abstract: Figure 2

Description

Title of the invention: Turboprop capable of providing an emergency wind turbine function and aircraft comprising such a turboprop Technical field

[0001] The invention relates to the field of turbomachines and more precisely that of turbopropellers.

[0002] The invention more specifically relates to a turboprop, an aircraft comprising such a turboprop and methods for controlling such a turboprop and aircraft. State of the prior art

[0003] In the event of an engine failure in flight of an aircraft, it is known to deploy a backup wind turbine, also known by the English terminology of "Ram air turbine", to provide an emergency source of energy to the aircraft and thus ensure the continuity of operation of essential onboard systems such as flight controls and critical flight instruments.

[0004] Such an emergency wind turbine comprises an autonomous propeller, a dedicated electric generator and a jack system which allows the wind turbine to be deployed when needed. As a result, the emergency wind turbine has a significant on-board mass, whereas, in normal operation of the aircraft, it is not used at all.

[0005] Therefore, it would be beneficial to remove such an emergency wind turbine in the event that, in the event of engine failure, it would be possible to supply energy from an alternative source. Statement of the invention

[0006] The invention thus aims to solve the problem set out above and thus aims to provide an alternative energy source to an emergency wind turbine, with a reduced on-board mass in comparison with an emergency wind turbine.

[0007] The invention relates to this end to a turboprop comprising: - a propeller, - a propeller shaft carrying the propeller, the propeller being a variable pitch propeller having a propeller pitch, - a rotating electrical machine having at least a first configuration in which it is mechanically coupled to the propeller shaft, and - at least one oil pump configured to supply a hydraulic circuit for adjusting the pitch of the propeller,

[0008] The oil pump being configured to be electrically driven.

[0009] Such an oil pump, by being configured to be electrically driven and unlike the oil pumps of the prior art, makes it possible to supply the hydraulic circuit for adjusting the pitch of the propeller, while the turboprop does not contribute to the propulsion. Thus, it is possible to adjust the pitch of the propeller in order to drive the propeller in rotation by windmill effect and therefore to rotate the propeller shaft and the electrical rotating machine which is mechanically coupled to it. Such rotation of the electrical rotating machine makes it possible to provide an emergency source of energy in the event of failure of the aircraft's turboprops without it being necessary to equip the aircraft with additional safety equipment. Thus, it is possible to limit the on-board mass of the aircraft.

[0010] It will be noted, moreover, that such a turboprop configuration, in addition to providing an emergency wind turbine function, allows fine adjustment of the propeller pitch. Thus, it is possible to adapt the propeller pitch to the speed of the aircraft and to provide sufficient energy production over a relatively large speed range of the aircraft.

[0011] the oil pump may be an engine oil pump configured to further be driven by a turbine of the turboprop, the engine oil pump preferably being mechanically coupled to said turbine by means of a freewheel.

[0012] In this way, it is possible to use the electrically driven turboprop engine oil pump in the turboprop's emergency wind mode while maintaining a conventional turboprop configuration when the latter participates in the propulsion of the aircraft.

[0013] It will be noted that in a conventional configuration the oil pump can be driven by the gas turbine, more precisely by its high pressure turbine and the high pressure shaft to which said high pressure turbine is mechanically coupled.

[0014] By engine oil pump, is meant above and in the rest of the invention, the pump of the turboprop configured to supply from an oil reservoir of the turboprop the various elements of the turboprop that need to be lubricated or supplied with oil pressure, including, in particular, the bearings and the hydraulic circuit for adjusting the pitch of the propeller. It will be noted that, in addition to the engine pump, the turboprop may comprise secondary pumps, called dedicated pumps, such as a dedicated pump of a propeller pitch management system or even an oil recovery pump.

[0015] The oil pump may be a hybrid engine oil pump configured to be driven either by the turbine or by an electric motor internal to the engine oil pump.

[0016] With such a configuration, the design of the engine oil pump does not have to be significantly adapted since its electrical drive is obtained by an external element, the electric motor, as is the case for a pump. engine oil of a prior art turboprop where it is the turbine which provides the drive.

[0017] The oil pump may be an auxiliary electric pump supplying the hydraulic circuit for adjusting a pitch of the propeller in parallel with a turboprop engine oil pump driven in rotation by a turbine of the turboprop.

[0018] In this way, the invention can easily be adapted to current turboprop engines by adding the auxiliary electric pump and the corresponding auxiliary oil circuit.

[0019] The turboprop may further comprise a propeller pitch management system comprising a dedicated oil pump and a servovalve, the dedicated oil pump and the servovalve being supplied with oil by the oil pump, the propeller pitch management system being arranged between the oil pump and the hydraulic circuit for adjusting the propeller pitch,

[0020] the turboprop further comprising a bypass system adapted to, when the oil pump is electrically driven, allow an oil supply to the hydraulic circuit for adjusting a pitch of the propeller via the servovalve by bypassing the dedicated oil pump of the propeller pitch management system.

[0021] Such a bypass system makes it possible to limit the oil pressure required to supply the hydraulic circuit for adjusting the propeller pitch and thus makes it possible to optimize the transition of the turboprop into emergency wind turbine mode.

[0022] The invention further relates to an aircraft comprising at least one turboprop according to the invention.

[0023] Such an aircraft, not having to include an emergency wind turbine, can have a reduced on-board mass in comparison with the aircraft of the prior art which must necessarily include an emergency wind turbine.

[0024] The invention further relates to a method for controlling a turboprop engine as an emergency wind turbine, in which the turboprop engine is a turboprop engine according to the invention, the method comprising the following steps: - drive the oil pump electrically so as to supply oil to the hydraulic circuit for adjusting the pitch of the propeller, - adjust the propeller pitch to generate the windmill effect to drive the propeller into rotation, - the rotating electrical machine being driven in rotation by the propeller shaft due to the mechanical coupling between them, generating electricity by the rotating electrical machine.

[0025] Such a method makes it possible, from a turboprop according to the invention, to switch said turboprop into an emergency wind turbine operating mode and thus to supply the aircraft with electricity when all of the aircraft's turboprop engines have ceased to function as propulsion.

[0026] The invention further relates to a method for controlling an aircraft comprising a plurality of turboprop engines according to the invention, comprising, while the aircraft is in flight, the following steps: - the plurality of turboprops having been stopped, receiving a request to place at least one turboprop in an emergency wind turbine type operating mode, - implementation by a turboprop of the plurality of turboprops of a control method according to the invention.

[0027] With such a method, it is possible to supply the aircraft with energy from at least one of the turboprop engines while the plurality of turboprop engines have stopped operating.

[0028] When implementing by a turboprop of the plurality of turboprops a control method according to the invention, the turboprop implementing the control method according to the invention may be the turboprop among the plurality of turboprops which is the last to have stopped.

[0029] It may further be provided: - in the case where, during the implementation of the control method by the last turboprop to have stopped, the latter proves incapable of switching to emergency wind turbine mode, identification among the other turboprops of the plurality of turboprops the one having the highest oil temperature, - implementation by the identified turboprop of the control method according to the invention.

[0030] In this way, with such possibilities, the turboprop switching to emergency wind turbine mode is the one with the best oil fluidity conditions for implementing the emergency wind turbine mode. Brief description of the drawings

[0031] The present invention will be better understood on reading the description of exemplary embodiments, given purely for informational purposes and in no way limiting, with reference to the appended drawings in which:

[0032] [Fig-1] illustrates a turboprop according to the invention.

[0033] [Fig.2] illustrates the kinematic diagram of the different elements of the turboprop during the initiation of an emergency wind turbine operating mode of the turboprop according to a first embodiment of the invention,

[0034] [Fig.3] illustrates the kinematic diagram of the different elements of the turboprop in emergency wind turbine operating mode of a turboprop according to the first embodiment of the invention.

[0035] [Fig.4] schematically illustrates the propeller pitch management system of a turboprop according to the first embodiment of the invention.

[0036] [Fig.5] illustrates the kinematic diagram of the different elements of the turboprop during the initiation of the emergency wind turbine operating mode of the turboprop according to a second embodiment of the invention in which the turboprop comprises a hybrid engine oil pump,

[0037] [Fig.6] illustrates the kinematic diagram of the different elements of the turboprop in emergency wind turbine operating mode of a turboprop according to the second embodiment of the invention.

[0038] [Fig.7] illustrates the kinematic diagram of the different elements of the turboprop during the initiation of the emergency wind turbine operating mode of the turboprop according to a third embodiment of the invention in which the turboprop comprises an auxiliary oil pump dedicated to the emergency wind turbine operating mode,

[0039] [Fig.8] illustrates the kinematic diagram of the different elements of the turboprop in emergency wind turbine operating mode of a turboprop according to the third embodiment of the invention.

[0040] [Fig.9] schematically illustrates the propeller pitch management system of a turboprop according to the third embodiment of the invention.

[0041] Identical, similar or equivalent parts of the different figures bear the same numerical references so as to facilitate the transition from one figure to another.

[0042] The different parts represented in the figures are not necessarily on a uniform scale, in order to make the figures more readable.

[0043] The different possibilities (variants and embodiments) must be understood as not being mutually exclusive and can be combined with each other.

[0044] Detailed presentation of particular production methods

[0045] [Fig.l] illustrates a turboprop 10, according to the invention which therefore has an operating mode of the emergency wind turbine type.

[0046] According to this present embodiment, the turboprop 10 is a free turbine turboprop. Thus, the turboprop 10 comprises a gas turbine 11 comprising a high-pressure turbine, not referenced, rotating a turbine shaft 14 and a compressor, not referenced, and a free turbine 111 which drives a secondary shaft, not referenced, of the gas turbine, concentric with the turbine shaft 14.

[0047] The turboprop 10 thus comprises, as shown in [Fig. 1], the gas turbine 11, a propeller 12, a propeller shaft 13, extending towards the gas turbine 11 and being coupled, as will be described later, to the free turbine 111 by means of a transmission. The propeller shaft 13 is surrounded by a protective casing 15. It is supported in the casing 15 by bearings 16 and 17. One of the bearings 16 is close to the propeller 12, and the other of the bearings 17 is adjacent to a toothed wheel 18 for driving the propeller shaft 13, which meshes with the transmission mentioned above. The rotating electrical machine 19 is, in this example of the invention, arranged concentrically around the propeller shaft 13, between the first bearing 16 and the toothed wheel 18, being surrounded by the casing 15.

[0048] Thus, in the present embodiment, the turboprop is a “conventional” turboprop.

[0049] It will be noted that, in the present embodiment, we are in a front-mounted configuration, such a configuration is of course provided as an illustration of the invention, it is not limited to this configuration alone. Thus, the invention is particularly applicable to turbochargers having a rear-mounted configuration.

[0050] In the present embodiment, the gas turbine 11 being of the free turbine type, it comprises the high pressure turbine and its turbine shaft 14, and the free turbine 111 and its secondary shaft. For more details concerning the drive kinematics provided by the turboprop in the context of the present embodiment of the invention, reference is made to the description of [Fig.2].

[0051] It will be noted, of course, that if the present configuration of the turboprop 10 described above is in accordance with the teaching of the document FR 3057029, it is not limited to this single configuration of the rotating electrical machine 19 in which the rotating electrical machine is arranged concentric with the propeller shaft 13. Thus, for example, the present teaching can easily be adapted to a remote configuration such as taught by the document US 2017 / 321601.

[0052] It will also be noted that, if the rotating electrical machine 19 is, in the context of this embodiment, a simple rotating electrical machine capable of providing a generator function, it is also conceivable, without departing from the invention, that such a rotating electrical machine 19 offers an electric propulsion function. Similarly, the rotating electrical machine 19 may have additional functions, such as those of powering a blade de-icing circuit according to the possibility taught by the document US 2019 / 233128. Indeed, given the similarities between the turboprop taught by the document FR 3057029 and that taught by the document US 2019 / 233128, the person skilled in the art is perfectly capable of applying the teaching of the document US 2019 / 233128 to the turboprop according to the present embodiment. For this purpose, it is possible to refer to the parts of document US 2019 / 233128 linked to [Fig.2] corresponding to paragraphs

[14] to

[20]

[0053] In order to supply fluid to the various bearings 22 of the turboprop 10 and a hydraulic circuit for adjusting a pitch of the propeller 12, the turboprop 10 according to this first embodiment comprises, as illustrated by the kinematic diagram of [Fig. 2], an engine oil pump 21. This engine oil pump 21 is, according to the principle of the invention, configured to be electrically driven. To do this, the turboprop 10 further comprises an auxiliary rotating electrical machine 21A mechanically coupled to the engine oil pump 21.

[0054] The rotating auxiliary electrical machine 21A is preferably coupled to the engine oil pump 21 so that in normal operation, the main oil pump 21 does not drive the electric pump 21A. Such a configuration can in particular be obtained by means of a freewheel not shown.

[0055] In the context of this first embodiment and according to a usual configuration of a turboprop, the engine oil pump 21 is further mechanically coupled to a turbine of the turboprop 10, here the gas turbine 11, i.e. the high-pressure turbine, of the turboprop. This mechanical coupling of the engine oil pump 21 is provided by means of a first freewheel 132 in such a way that the gas turbine drives the engine oil pump when the turboprop is in operation and in that the gas turbine 11 is mechanically decoupled from the engine oil pump 21 when the latter is driven by the auxiliary rotating electrical machine 21A.

[0056] It will be noted, moreover, as shown in [Fig. 2], in the context of initiating the emergency wind turbine type operating mode, that a bypass system is provided suitable for, when the engine oil pump 21 is electrically driven, authorizing, via the servovalve 26, a supply of oil to the hydraulic circuit 25 for adjusting a pitch of the propeller 12 by bypassing the dedicated oil pump 122 of a propeller pitch management system 121. Such a bypass makes it possible to optimize the supply of oil to the hydraulic adjustment circuit 25 as described below in connection with [Fig. 4].

[0057] Such a turboprop 10 is suitable for implementing a method of controlling the latter as an emergency wind turbine, the method comprising the following steps: - drive the engine oil pump 21 electrically by means of the auxiliary rotating electrical machine 21A so as to supply oil to the hydraulic circuit for adjusting the pitch of the propeller 12, - adjusting the pitch of the propeller in order to achieve the windmill effect to drive the propeller in rotation, this adjustment preferably being carried out in such a way as to maximize said windmill effect, - the rotating electrical machine 19 being driven in rotation by the propeller shaft 13 due to the mechanical coupling between them, generation of electricity by the rotating electrical machine 19.

[0058] It will be noted that the turboprop 10 comprises, for the implementation of such a method, a control unit, also known by the English acronym FADEC, for “Full Authority Digital Engine Control”, which is configured for the implementation of such a control method when the turboprop 10 is commanded to be placed in emergency wind turbine mode.

[0059] To do this during the step of driving the engine oil pump 21 electrically, the turboprop 10 can have the schematic kinetic configuration illustrated in [Fig.2].

[0060] Thus, as illustrated in [Fig. 2], in the context of initiating the emergency wind turbine mode, the rotating electrical machine 19 is directly coupled to the propeller shaft 13, and therefore to the propeller 12 by means of a set of gears to achieve speed matching between the rotating electrical machine 19 and the propeller shaft 13. Among this set of gears, the input gear of the propeller shaft 13 is also coupled to the free turbine 111 of the gas turbine 11, through a second freewheel 133, and to the propeller control unit 121. It will be noted that, for reasons of simplification of the kinematic diagram, the free turbine 111 is artificially separated from the gas turbine, since the free turbine 111 is rotationally decoupled from the turbine shaft 14.The engine oil pump 21 is mechanically coupled to the auxiliary rotating electrical machine 21A such that the engine oil pump 21 is electrically driven by the auxiliary rotating electrical machine 21A. The engine oil pump 21 is also mechanically coupled to the gas turbine 11, or more precisely to the high-pressure turbine and to the turbine shaft 14, by means of the first freewheel 132.

[0061] With such freewheels 132, 133, it is not necessary to use selective coupling systems when switching from the conventional propulsion mode, provided by the gas turbine 11, to the emergency wind turbine mode. The drive mechanism is therefore simplified and therefore presents simplified maintenance. Thus, these freewheels 132, 133 make it possible to decouple the engine oil pump 21 from the gas turbine 11 when it is electrically driven and to decouple the propeller shaft 13 from the free turbine 111, when the turbojet 10 operates in emergency wind turbine mode.

[0062] As indicated above, in the context of this first embodiment, the bypass system allows an oil supply, via the servovalve 26, illustrated in [Fig. 4], to the hydraulic circuit 25 for adjusting the pitch of the propeller 12 by bypassing the dedicated oil pump 122 of the propeller pitch management system 121 which, being driven by the propeller shaft 13, is stopped as long as the propeller 12 is not set in rotation.

[0063] It will be noted that, according to this embodiment, in accordance with a usual configuration of a turboprop 10, the dedicated oil pump 122 is part of a turboprop control unit (propeller pitch management system 121, also known by the acronym PCU for “propeller control unit”), or of a turboprop control and protection unit (also known by the acronym PCPU for “propeller control and protection unit”, also referred to in the present text as “propeller pitch management system 121”). Similarly, the rotating electrical machine 19 may be included in a power and accessory gearbox (also known by the acronym PAGB for “Power and Accessory Gear Box”).

[0064] This driving of the engine oil pump 21 by the rotating electrical machine 21A thus allows the hydraulic circuit for adjusting the pitch of the propeller 12 to be supplied with oil via the propeller pitch management system 121 and therefore a modification of the pitch of the propeller 12. It will be noted that in this configuration, the engine oil pump 21 also allows the bearings 22 of the turboprop 10 to be supplied. Once the adjustment of the pitch of the propeller allows the windmill effect driving the propeller into rotation to be taken advantage of, the emergency wind turbine mode is initiated and the propeller 12 begins to rotate.

[0065] Thus, in the emergency wind turbine mode, the propeller having started to turn, the kinematic diagram of the turboprop 10 evolves and becomes consistent with the diagram shown in [Fig. 3]. It can be seen that this kinematic diagram is different from that of the priming illustrated in [Fig. 2]: the dedicated oil pump 122 of the propeller pitch management system 121, being driven in rotation, no longer presents an obstacle to the passage of oil coming from the engine oil pump 21. As a result, as described below in connection with [Fig. 4], the bypass circuit is made inactive and the servovalve 26 is supplied through the dedicated oil pump 123 allowing the supply of the hydraulic adjustment circuit 25 and, as a result, an adapted adjustment of the pitch of the propeller 12.

[0066] In the context of this kinematic diagram, the rotating electrical machine 19, being driven in rotation by the propeller 12, provides a generation of electricity to power, according to the principle of an emergency wind turbine, the equipped aircraft and thus ensure the continued operation of essential aircraft systems such as flight controls and critical flight instruments.

[0067] [Fig. 4] illustrates the oil circuit of the turboprop 10 according to this first embodiment. It can be seen that, according to a usual configuration of a turboprop 10, the engine oil pump 21 makes it possible to recover the oils collected in the bottom of the accessory box 27 in order to reinject them into the oil circuit. Thus, a portion of this oil is transmitted to the servovalve 26 through the dedicated oil pump 122 of the propeller pitch management system 121. The bypass system, in order to allow the servovalve 26 to be supplied while the dedicated gearbox oil pump 122 is stopped, comprises a bypass valve 123 controlled as a function of the oil pressure supplied by the oil pump 122 of the propeller pitch management system 121.Thus, when the oil pressure supplied by the dedicated oil pump 122 of the propeller pitch management system 121 is lower than a certain value, that is to say that the dedicated oil pump 122 of the propeller pitch management system 121 is stopped or is rotating little, the bypass valve 123 is opened to allow supply of the servovalve 26 by bypassing the dedicated oil pump 122 of the propeller pitch management system 121. After initiating the emergency wind turbine mode, the dedicated oil pump 122 of the propeller pitch management system 121 being driven in rotation by the propeller shaft, the oil pressure supplied by the dedicated oil pump 122 of the propeller pitch management system 121 increases.When the oil pressure supplied by the dedicated oil pump 122 becomes greater than a certain value deemed sufficient, for example greater than or equal to 2, or even 4 bars, the bypass valve 123 can be closed and thus only keep the oil supply to the servovalve 26 by the dedicated oil pump 122 of the propeller pitch management system 121.

[0068] It will be noted that, in Figures 4 and 9, a servovalve 26 is shown, controlled by a control unit of the turboprop 10 in order to adjust the hydraulic pressure transmitted to the actuator, not shown, making it possible to adjust the pitch of the propeller 12.

[0069] The oil circuit of the turboprop 10 may also comprise, as illustrated in [Fig. 4] a pressure relief valve 125 adapted to recirculate the flow of oil generated by the dedicated oil pump 122 of the propeller pitch management system 121 which is in excess compared to the oil consumption required by the propeller 12. Such a pressure relief valve 125 may thus, for example, be adjusted to limit the pressure applied to the hydraulic circuit for adjusting the pitch of the propeller to a value lower than 50 bars, or even 35 bars, or even 25 bars.

[0070] Such a turboprop 10 makes it possible, when it equips an aircraft, to provide an emergency wind turbine function. When an aircraft is equipped with a plurality of turboprops 10 according to the invention, it can be configured to implement a control method comprising, while the aircraft is in flight, the following steps:

[0071] - all of the turboprops 10 of the plurality of turboprops having passed when stopped, receiving a request to place at least one turbomachine in an emergency wind turbine type operating mode,

[0072] - implementation, by one of the turboprops 10 of the plurality of turboprops, of a method for controlling the latter as an emergency wind turbine, as mentioned above, this turboprop 10 being preferably the turboprop 10 among the plurality of turboprops which is the last to have stopped.

[0073] It will be noted that, in the case where, during the implementation of the control method by the last turboprop to have stopped, the latter proves incapable of switching to emergency wind turbine mode, it can be identified among the other turboprops of the plurality of turboprops 10 that having the highest oil temperature. Once said turboprop 10 having the highest oil temperature has been identified, the latter can be configured to implement the control method according to the invention to be placed in emergency wind turbine mode.

[0074] Whether for the identification of the last turboprop 10 to have stopped, or the identification of the turboprop 10, among the other turboprops 10, the one having the highest oil temperature, each turboprop 10 can have its control unit configured to communicate with the control units of the other turboprops of the aircraft. According to this possibility, the control units can communicate with each other status information such as an operating status, to know that it is the last turboprop to have stopped, and an oil temperature, to identify the turboprop 10, among the other propellers 10, the one having the highest oil temperature.

[0075] It will be noted that, as a variant, it may be a control unit of the aircraft or a pilot of the aircraft who determines that it is the turboprop 10 to switch to emergency wind turbine mode and who controls said turboprop 10 to implement the control method already described.

[0076] Figures 5 and 6 illustrate the kinematic diagrams of the initiation of the emergency wind turbine mode and the emergency wind turbine mode in the context of a second embodiment of the invention in which the engine oil pump 21 is a hybrid pump configured to be driven both electrically and by the gas turbine.

[0077] Thus, a turbomachine 10 according to this second embodiment differs from a turboprop 10 according to the first embodiment in that the engine oil pump is a hybrid pump and in that no auxiliary rotating electrical machine 21 A is provided.

[0078] In this way, in accordance with the first embodiment and as illustrated in [Fig. 5], when initiating the emergency wind turbine mode of the turboprop, the engine oil pump 21 is electrically driven by an internal electric motor and makes it possible to supply both the bearings 22 of the turboprop 10 and the hydraulic adjustment circuit 25. The bypass system, according to a configuration similar to that illustrated in [Fig. 4], makes it possible to supply the hydraulic adjustment circuit 25 by bypassing the dedicated oil pump 122 of the propeller pitch management system 121.

[0079] As illustrated in [Fig.6], once the wind turbine mode has been initiated and the propeller has been set into rotation, the dedicated oil pump 122 of the propeller pitch management system 121 being driven by the propeller shaft 13, the bypass system becomes inoperative and the servovalve 26 is supplied by the engine oil pump 21 through the dedicated oil pump 122 of the propeller pitch management system 121 as described in the context of the first embodiment.

[0080] A turboprop 10 according to this second embodiment can be placed in an emergency wind turbine mode according to a control method identical to that of the first embodiment.

[0081] Figures 7 and 8 illustrate the kinematic diagrams of the initiation of the emergency wind turbine mode and the emergency wind turbine mode within the framework of a third embodiment of the invention in which an auxiliary electric oil pump 21B is provided, adapted to be electrically driven and to supply oil to the servovalve 26 and the bearings 22 of the turboprop 10.

[0082] A turboprop 10 according to this third embodiment differs from a turboprop 10 according to the first embodiment in that it comprises the auxiliary electric oil pump 21B in parallel with the engine oil pump 21 and in that no auxiliary rotating electric machine 21A is provided.

[0083] In this way, in accordance with the first embodiment and as illustrated in [Fig. 7], when the emergency wind turbine mode of the turboprop 10 is initiated, while the engine oil pump 21 is stopped, the auxiliary electric oil pump 21B is electrically driven and makes it possible to supply both the bearings 22 of the turboprop 10 and the servovalve 26 of the propeller pitch management system 121 and then the hydraulic adjustment circuit 25. A bypass system, according to a configuration which is described below in connection with [Fig. 9], here again makes it possible to supply the hydraulic adjustment circuit 25 via the servovalve 26 by bypassing the oil pump 122 of the propeller pitch management system 121.

[0084] In the same way as for the first and second embodiments and as illustrated in [Fig.8], once the wind turbine mode has been started and the propeller has been set into rotation, the dedicated oil pump 122 of the propeller pitch management system 121 being driven by the propeller shaft 13, the bypass system becomes inoperative and the supply of the hydraulic adjustment circuit 25 is carried out by the auxiliary electric oil pump 21B through the dedicated oil pump 122 and the servovalve 26 of the propeller pitch management system 121 as described in the context of the first embodiment.

[0085] [Fig. 9] illustrates the oil circuit of the turboprop 10 according to this third embodiment. Such an oil circuit differs from an oil circuit according to the first embodiment in that two oil supply circuits are provided in parallel with each other, one supplied by the engine oil pump 21 and the other by the auxiliary electric oil pump 21B to supply both the servovalve 26 of the propeller pitch management system 121 and the bearings 22 of the turboprop 10. Thus, as shown in [Fig. 9], each of the engine oil pump 21 and the auxiliary electric oil pump 21B makes it possible to recover the oils collected in the bottom of the accessory box 27 in order to reinject them into the oil circuit.

[0086] In order to avoid a loss of pressure in the inactive pump, among the engine oil pump 21 and the auxiliary electric oil pump 21B, a non-return valve system 126A, 126B is provided on each of the supply circuits supplied by the engine oil pump 21 and the auxiliary electric oil pump 21B.

Claims

Claims

1. Turbopropeller (10) comprising: - a propeller (12), - a propeller shaft (13) carrying the propeller (12), the propeller (12) being a variable-pitch propeller having a propeller pitch, - a rotating electrical machine (19) having at least a first configuration in which it is mechanically coupled to the propeller shaft (13), and - at least one oil pump (21, 21B) configured to supply a hydraulic circuit for adjusting the pitch of the propeller (12), configured to be electrically driven. the turbopropeller (10) being characterized in that the oil pump is also configured to supply fluid to bearings (22) of the turbopropeller (10).

2. Turboprop (10) according to claim 1, wherein the oil pump (21) is an engine oil pump configured to further be driven by a turbine (11) of the turboprop (10), the engine oil pump (21) being preferentially mechanically coupled to said turbine (11) by means of a freewheel (132).

3. The turboprop (10) of claim 2, wherein the oil pump (21) is a hybrid engine oil pump configured to be driven either by the turbine (11) or by an electric motor internal to the engine oil pump (21).

4. Turboprop (10) according to claim 1, in which the oil pump (21B) is an auxiliary electric pump (21B) supplying the hydraulic circuit (25) for adjusting a pitch of the propeller (12) in parallel with an engine oil pump (21) of the turboprop (10) driven in rotation by a turbine (11) of the turboprop (10).

5. A turboprop (10) according to any one of claims 1 to 4 further comprising a propeller pitch management system (121) comprising a dedicated oil pump (122) and a servovalve (26), the dedicated oil pump (122) and the servovalve (36) being supplied with oil by the oil pump (21, 21B), the propeller pitch management system (121) being arranged between the oil pump (21, 21B) and the hydraulic circuit (25) for adjusting the pitch of the propeller (12), wherein the turboprop (10) further comprises a bypass system adapted for, when the oil pump (21, 21B) is electrically driven, allowing an oil supply to the hydraulic circuit for adjusting a propeller pitch (12) via the servovalve (26) bypassing the dedicated oil pump (122) of the propeller pitch management system (121).

6. Aircraft comprising at least one turboprop (10) according to any one of claims 1 to 5.

7. A method of controlling a turboprop (10) as a backup wind turbine, wherein the turboprop (10) is a turboprop according to any one of claims 1 to 5, the method comprising the following steps: - driving the oil pump (21, 21B) electrically so as to supply oil to the hydraulic circuit (25) for adjusting a pitch of the propeller (12) and the bearings (22) of the turboprop (10), - adjusting the pitch of the propeller (12) in order to generate the windmill effect to drive the propeller (12) in rotation, - the rotating electrical machine (19) being driven in rotation by the propeller shaft (13) due to the mechanical coupling between them, generating electricity by the rotating electrical machine (19).

8. A method of controlling an aircraft comprising a plurality of turboprops (10) according to any one of claims 1 to 5, comprising, while the aircraft is in flight, the following steps: - the plurality of turboprops (10) having come to a standstill, receiving a request to place at least one turboprop (10) in an operating mode of the emergency wind turbine type, - implementing by a turboprop (10) of the plurality of turboprops a control method according to claim 7

9. / . A control method according to claim 8, wherein, when a turboprop (10) of the plurality of turboprops implements a control method according to claim 7, the turboprop (10) implementing the control method according to claim 7 is the turboprop (10) among the plurality of turboprops (10) which is the last to have stopped.

10. Control method according to claim 9, in which it is further provided: - in the case where during the implementation of the control method by the last turboprop (10) to have stopped, the latter proves incapable of switching to emergency wind turbine mode, identifying among the other turboprops (10) of the plurality of turboprops (10) the one having the highest oil temperature, - implementation by the identified turboprop (10) of the control method according to claim 7.

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