Vtol aircraft propulsion system

Abstract

The invention relates to an aircraft propulsion system comprising a stator and a rotor (1), which is configured to rotate relative to the stator about an axis. The rotor (1) comprises a hub (5) and a blade (7) mounted on the hub (5) so as to be able to pivot between at least a first position and a second position. The rotor (1) further comprises a pitch device (19) capable of moving the blade (7) between its first position and its second position. The pitch device (19) comprises an inertial device, which is connected to the blade (7) and arranged so as to move relative to the hub (5) between at least a position close to the axis (3), in which the pitch device (19) constrains the blade (7) in the first position, and a position away from the axis (3), in which the pitch device (19) constrains the blade (7) in the second position. The pitch device (19) further comprises an elastic member, which returns the inertial device to the position close to the axis. The pitch device (19) is configured such that, when the speed of rotation of the rotor (1) relative to the stator exceeds a threshold value, the inertial device moves from the position close to the axis to the position away from the axis by centrifugal effect.

Description

VTOL aircraft propulsion system

[0001] The invention relates to the field of vertical take-off and landing aircraft, also referred to as VTOL in the art (from the English equivalent "Vertical Take-Off and Landing"). More particularly, the invention relates to a VTOL aircraft propulsion system.

[0002] A VTOL aircraft generally includes a propulsion system having a plurality of rotors, each rotor configured to rotate about an axis of rotation relative to a respective stator. Each rotor has a drive plane, which extends generally perpendicular to its axis of rotation. Typically, the rotors each include a hub equipped with a plurality of blades, generally at least six blades.

[0003] The rotating rotors are capable of jointly producing a primarily vertical movement of the aircraft, particularly during takeoff and landing. A VTOL aircraft can take off from and land on a limited ground infrastructure. This makes it particularly suitable for use in highly constrained environments, such as cities, and reduces the footprint required for its operation.

[0004] A first configuration of VTOL aircraft is known, in which the rotation of the rotors alone provides the aircraft's lift, not only in the vertical flight phases, but also in the forward flight phases. This is the case, for example, of the configuration of the aircraft known as "Volocity" from the Volocopter company. The aircraft is then generally wingless. However, aircraft in this first configuration have a fairly low forward flight speed, low energy autonomy and significant noise pollution.

[0005] This is why a second configuration is generally preferred, in which aircraft are equipped with wings. These wings produce most of the aircraft's lift in forward flight, while in vertical flight, this lift remains mainly generated by the rotors.

[0006] According to a first type of aircraft with this second configuration, the rotors are installed on the wings, in such a way that the blades of these rotors protrude from the wings. This is the case, for example, of the aircraft known as "VX-4" from the company Vertical Aerospace. In forward flight, these rotors can either be folded so as to participate in the forward flight, or left as they are. In the first case, the implementation of the folding leads to additional mechanical complexity, without necessarily being accompanied by a significant gain in performance. In the second case, significant drag is generated.

[0007] According to a second type of aircraft having this second configuration, the wings comprise a fairing provided with through ducts, each of these ducts connecting the lower surface of the wing to the upper surface of the latter. The rotors are each housed in a respective duct.

[0008] For aircraft of this type, the aim is to design a propulsion system that achieves high lift in vertical flight, while generating low drag in forward flight. As is known, the use of pitching devices can help achieve this objective. The pitching devices are connected to the rotor blades and configured to modify their orientation relative to the airflow entering the through ducts.

[0009] Such pitching devices vary the inclination of the blades relative to their respective hubs. More specifically, the pitching devices vary the pitch angles, or "pitch," of the blades. The pitch of a blade corresponds to the angle formed between its chord line and the drive plane of its respective rotor.

[0010] The blade pitch depends on the flight phase. In particular, the blade pitch is determined based on the general direction of the airflow around the aircraft during the flight phase, and based on the role of the rotors during this phase.

[0011] In vertical flight, a generally vertical airflow flows around the aircraft. The rotors are operational. The pitching devices cause the blades to assume an initial position relative to their hub, called the "operational position". For example, this operational position corresponds, for each blade, to a high pitch value.

[0012] In forward flight, a generally horizontal airflow flows around the aircraft. The rotors are stationary, and the aim is to minimize the drag induced by the blades. The pitching devices cause the blades to assume a second position relative to their hub, called the "feathered position." For example, this feathered position corresponds, for each blade, to a low pitch value, or at least lower than that of the operational position.

[0013] Wedging devices are known comprising one or more actuators, for example of the electric or hydraulic type.

[0014] A first type of stall device comprises, for each rotor, an actuator and an assembly formed of an inertial device and a spring. The assemblies formed of the inertial devices and the springs exert a restoring force on the blades, which forces the latter into the feathered position. The actuators are configured so as to oppose this restoring force and to force the blades into the operational position during the vertical flight phase.

[0015] A second type of stall device comprises, for each rotor, an actuator arranged so as to alternately constrain the blades, either in the feathered position during the forward flight phase, or in the operational position during the vertical flight phase.

[0016] Such shim devices are both bulky and heavy, especially since the rotors with which these devices are associated have a high number of blades. In particular, these devices are rarely used for rotors with more than ten blades.

[0017] Furthermore, such pitch control devices are usually designed to be connected to a central aircraft control system, which provides a pitch control function for the rotor blades. It is therefore necessary to integrate these devices directly onto the aircraft.

[0018] Finally, the presence of actuators is a risk factor in terms of maintenance. Indeed, if one of the actuators is poorly maintained and breaks down or malfunctions, the aircraft's drag is significantly impacted.

[0019] The invention improves the situation. To this end, an aircraft propulsion system is proposed, which comprises a stator and a rotor, configured to rotate relative to the stator about an axis. The rotor comprises a hub and a blade, mounted on the hub so as to be able to pivot between at least a first position and a second position. The rotor further comprises a wedging device, capable of moving the blade between its first position and its second position. The wedging device comprises an inertial device, connected to the blade and arranged so as to move relative to the hub between at least one position close to the axis, in which the wedging device forces the blade into the first position, and a position remote from the axis, in which the wedging device forces the blade into the second position. The wedging device further comprises an elastic member, which returns the inertial device towards the position close to the axis.The stall device is configured so that when the rotational speed of the rotor relative to the stator exceeds a threshold value, the inertial device moves from the position close to the axis to the position far from the axis by centrifugal effect.

[0020] The system according to the invention is lighter and more compact than prior art solutions, in particular due to the absence of actuators and a central control system. The compactness of the timing device associated with each blade makes this propulsion system easily transposable for rotors with more than ten blades.

[0021] The system's stalling device according to the invention operates passively, i.e., the device is actuated without the need for an external energy source. Such a device is particularly advantageous because it eliminates a potential cause of failure and is therefore more reliable. This makes it possible, in particular, to facilitate the certification procedure for the propulsion system.

[0022] Optional features of the invention, complementary or substitutive, are set out below: the inertial device is arranged so as to pivot relative to the hub between the position close to the axis and the position far from the axis; the wedging device further comprises a stop surface for the inertial device, active when the inertial device is in the position close to the axis or in the position far from the axis; the wedging device comprises an opening, capable of receiving at least part of the inertial device, and which has an edge, which forms a stop surface for the inertial device, which is active when the inertial device is in the position close to the axis or in the position far from the axis;the wedging device comprises an opening, capable of receiving at least part of the inertial device, and which has a pair of mutually opposite edges, which form abutment surfaces for the inertial device, one being active when the inertial device is in the position close to the axis, the other being active when the inertial device is in the position far from the axis; the inertial device is arranged to pivot relative to the hub between the position close to the axis and the position far from the axis, the opening being shaped as a rotation guide for the inertial device; the inertial device and the blade are arranged to pivot relative to the hub about the same axis of rotation between the position close to the axis, respectively the first position, and the position far from the axis, respectively the second position;the blade comprises an end portion, by means of which the blade is connected to the hub, and the inertial device comprises a flyweight and a pair of flanges, each of which connects the flyweight to the end portion, the flyweight being shaped as a spacer for the pair of flanges and the end portion; the elastic member is shaped as a torsion spring, wound around at least part of the end portion, and which has a pair of branches, one of these branches being arranged to cooperate with the hub, the other of these branches being arranged to cooperate with one of the flanges of the inertial device; the inertial device and the blade are integral with each other;the wedging device further comprises a locking element, capable of cooperating with the inertial device so as to maintain the latter in an intermediate position between the position close to the axis and the position far from the axis relative to the hub, which corresponds to a position of the intermediate blade between its first position and its second position relative to the hub; the rotor comprises an additional blade, mounted on the hub so as to be able to pivot between at least a first position and a second position, as well as an additional wedging device, capable of moving the additional blade between its first position and its second position, and the wedging device and the additional wedging device are mutually connected so as to synchronize the movement of the blade and the additional blade between their respective first position and second position.;

[0023] Other characteristics and advantages of the invention are set out in detail in the description below, made with reference to the appended drawings, in which:1 represents a propulsion system according to the invention, in side view;1 is a sectional view of the system of the;1 is an isometric perspective view of the system of the;1 is an exploded view of a section of the system of the;1 is similar to the;1 represents a detail of a wedging device according to the invention, in isometric perspective;1 is similar to the;1 is similar to the;1 is an isometric perspective view of a wedging device and a blade of the system according to the invention, the blade being in a first position;1 is a front view of the wedging device and the blade of the;1 is similar to the, the blade being in a second position;1 is a front view of the wedging device and the blade of the.

[0024] The drawings and the description below contain, for the most part, elements of a certain character. They may therefore not only serve to better understand the present invention, but also contribute to its definition, if necessary.

[0025] Reference is made to Figures 1 to 5.

[0026] These figures represent a propulsion system for a VTOL type aircraft.

[0027] Typically, the VTOL type aircraft has a wing (not shown), which includes a fairing. The fairing has an upper surface shaped into an upper surface and a lower surface shaped into a lower surface. The upper surface and the lower surface are mutually opposed in a direction of the wing, here the transverse direction of the wing. The wing further comprises at least one through-duct, arranged in the fairing and connecting the lower surface to the upper surface.

[0028] The propulsion system comprises a rotor 1, typically housed at least partly in the through duct of the wing, and a drive device 17, shaped so as to support the rotor 1 on the fairing and to drive this rotor 1 in rotation about an axis of rotation 3. The rotation speed of the rotor 1 can be controlled to different values ​​during flight.

[0029] Here, the drive device 17 comprises an electric motor part 171, mechanically connected to the rotor 1, and a stator shaped in platinum 173, forming a mechanical interface between the electric motor 171 and the fairing. The drive device 17 further comprises an encoder 177, electrically connected to the electric motor 171, and a connector part 175, ensuring liquid cooling of the electric motor 171.

[0030] Typically, the rotor 1 is held in the through duct in such a way that its axis of rotation 3 forms with the transverse direction of the wing a rotor inclination angle of between approximately 0° and approximately 30°, preferably between 0° and 5°. For example, this angle is close to 1.5° or 3°. The inclination of the axis of rotation 3 of the rotor 1 relative to the transverse direction of the wing portion 1 improves yaw control. Any plane orthogonal to the axis of rotation 3 of the rotor 1 is called the rotor plane.

[0031] The rotor 1 comprises a hub 5 and a plurality of blades 7 each mounted on the hub 5 with the possibility of pivoting. Here, the rotor 1 comprises eleven blades 7. The blades 7 are distributed around the axis of rotation 3.

[0032] Each blade 7 has a main portion or active portion 43, arranged so as to be in contact with the air flows entering the through duct during the flight phases. The active portion 43 of each blade 7 has an end or tip 13, opposite the hub 5, which is free. Each blade 7 also has a root 15, connected to its active portion 43, opposite the tip 13 of the latter. Here, the active portion 43 and the root 15 of each blade 7 are made in a single piece.

[0033] Each blade 7 further has an end portion or fork 39, connected to its root 15. Here, each blade 7 is connected to the hub 5 via its fork 39. Here, the forks 39 are produced in the form of separate parts and assembled integrally to the root 15 of one of the blades 7, so as to facilitate the maintenance of these blades 7.

[0034] Here, the hub 5 has a pair of flanges shaped as carbon discs 9 (hidden on the), mutually opposite along the axis of rotation 3. The hub 5 also has a plurality of pairs of jaws 11, held between the carbon discs 9. The jaws 11 are assembled integrally with the carbon discs 9, here by screwing. Each pair of jaws 11 grips one of the blades 7 while allowing the latter to pivot relative to the hub 5. Here, each pair of jaws 11 grips the fork 39 of one of the blades 7.

[0035] Each blade 7 extends along a main direction, or longitudinal axis. For each blade 7, the longitudinal axis coincides with the axis of rotation of this blade 7 relative to the hub 5. The longitudinal axes of the blades 7 are arranged radially relative to the axis of rotation 3 of the rotor 1. The longitudinal axes of the blades 7 extend in one of the planes of the rotor, which is called the drive plane.

[0036] Each blade 7 has a front portion shaped into a leading edge and a rear portion shaped into a trailing edge. The leading edge and the trailing edge are mutually opposite relative to the longitudinal axis of this blade 7. Each blade 7 has, according to a cross-section to its longitudinal axis, a profile. On this profile, the shortest of the straight lines which connect the leading edge to the trailing edge is called the chord line. The chord line of the profile at the root of the blade 15 and the chord line of the profile at the tip of the blade 13 form between them a twist angle for this blade 7. In a known manner, the blades 7 may have a twist, that is to say that their respective twist angle is non-zero. For example, this twist angle is between 10° and 15°.

[0037] For each blade 7, the chord line of the root profile 15 forms an angle with the drive plane, called the pitch angle or pitch. The rotation of the blades 7 relative to the hub 5 varies their respective pitch. The blades 7 are said to have variable pitch.

[0038] The rotor 1 further comprises at least one wedging device 19, configured so as to rotate one of the blades 7 relative to the hub 5. Here, the rotor 1 comprises a plurality of wedging devices 19, configured so as to each rotate one of the blades 7 relative to the hub 5.

[0039] The rotor 1 further has a cover 61 (shown transparently in Figures 1 and 3), also known in the prior art as a "spinner". This cover 61 covers its hub 5, at least an upper part thereof. The wedging devices 19 may, as here, be arranged under the cover 61, so as to be protected from any external aggression and to have improved aerodynamic performance.

[0040] Reference is made to Figures 6 to 12.

[0041] These figures represent details of the propulsion system according to the invention, and in particular details of the wedging devices 19 and the blades 7. In figures 6 and 9 to 12, the jaws 11 are shown in transparency.

[0042] An embodiment of one of the wedging devices 19 according to the invention is described below. Here, all of the wedging devices 19 of the propulsion system are produced in a similar manner.

[0043] The wedging device 19 comprises an inertial device 33, which is connected to one of the blades 7, close to the root 15 thereof. Here, the inertial device is connected to the fork 39 of this blade 7. The inertial device 33 is arranged so as to move relative to the hub 5 when the rotational speed of the rotor 1 relative to the stator crosses a threshold value. The inertial device 33 is movable between at least a first position, close to the axis of rotation 3 of the rotor 1, and a second position, distant from this axis. In Figures 9 and 10, the inertial device 33 is in its first position. In Figures 1 to 8, 11 and 12, the inertial device 33 is in its second position.

[0044] The inertial device 33 is arranged so as to constrain the blade 7 into a first position relative to the hub 5, corresponding to a first pitch value, when this inertial device 33 is in its first position. The inertial device 33 is further arranged so as to constrain the blade 7 to which this inertial device 33 is connected into a second position relative to the hub 5, corresponding to a second pitch value, when this inertial device 33 is in its second position. The inertial device 33 is configured so as to move from the first position to the second position under the centrifugal effect generated by the rotation of the rotor 1 relative to the stator when the speed of this rotation crosses a threshold value.

[0045] The wedging device 19 further comprises an elastic member, connected to the inertial device 33 and to the blade 7. The elastic member exerts a force which tends to return the inertial device 33 to its first position, which tends to return this blade 7 to its first position.

[0046] Here, the first position of the blade 7 corresponds to a feathered position, while the second position of this blade 7 corresponds to an operational position. Here, this corresponds to a first low pitch value, for example between 0° and 15°, and to a second high pitch value, for example between 25° and 45°, in particular between 30° and 40°.

[0047] In forward flight of the aircraft, a generally horizontal airflow flows around the aircraft. The rotor 1 is stationary relative to the stator. The inertial device 33 is in its first position, i.e. close to the axis of rotation 3 of the rotor, so as to constrain the blade 7 in its first position, here its feathered position. The drag induced by the rotor 1 is thus reduced.

[0048] In vertical flight of the aircraft, a flow of air in a generally vertical direction flows around the aircraft. The rotor 1 is rotating relative to the stator, at a rotational speed at least greater than a speed called the minimum operational speed. Here, this minimum operational speed is at least greater than 500 rpm, for example of the order of 2000 rpm. The inertial device 33 is in its second position, i.e. away from the axis of rotation 3 of the rotor, so as to constrain the blade 7 in its second position, here its operational position. The lift induced by the rotor 1 is thus increased.

[0049] The centrifugal effect generated by the rotation of the rotor 1 tends to move the inertial device 33 from its first position to its second position, while the return force of the elastic member tends to maintain the inertial device 33 in its first position, or to return it to it. When the rotational speed of the rotor 1 increases, the intensity of the centrifugal effect exerted on the inertial device 33 increases. This intensity exceeds the intensity of the return force when the rotational speed of the rotor 1 crosses the threshold value.

[0050] The inertial device 33 and the elastic member are dimensioned so that the threshold value is adapted to the use cases of the aircraft. In particular, the inertial device 33 and the elastic member are dimensioned so that this threshold value is far from the natural operating modes of the aircraft. Here, the inertial device 33 and the elastic member are dimensioned so that the threshold value is between 500 rpm and the minimum operational speed, here 2000 rpm. For example, the threshold value is of the order of 500 rpm. The dimensioning of the setting device 19 can be refined by taking into account the aerodynamic contribution of the air flows on the active portion 43 of the blade 7.

[0051] The wedging device 19 has a first stop surface 25 for the inertial device 33, active when the inertial device 33 is in its first position. The wedging device 19 further has a second stop surface 27 for the inertial device 33, active when the inertial device 33 is in its second position.

[0052] The wedging device 19 may further have additional stop surfaces for the inertial device 33, corresponding to additional positions of the inertial device 33 and the blade 7 relative to the hub 5. These additional positions may, for example, correspond to intermediate positions of the inertial device 33 between its first position and its second position. The wedging device 19 then comprises a locking element, capable of cooperating with the inertial device 33 so as to maintain the latter in these additional positions.

[0053] The inertial device 33 may, as here, be arranged so as to be able to rotate relative to the hub 5, between its first position and its second position. The rotation of the inertial device 33 from its first position to its second position causes the rotation of the blade 7 from its first position to its second position, and vice versa. Here, the axis of rotation of the inertial device 33 relative to the hub 5 coincides with the axis of rotation 37 of the blade 7 relative to the hub 5. Here, the inertial device 33 and the blade 7 are assembled integrally with each other.

[0054] The elastic member can, as here, be shaped into a torsion spring 23. The torsion spring 23 is wound on at least part of the fork 39 of the blade 7. The torsion spring 23 has a first branch 51, connected to the inertial device 33, and a second branch 53, connected to the hub 5, for example to one of its carbon discs 9.

[0055] At least part of the blade 7 and the inertial device 33 can be arranged on either side of one of the carbon discs 9 of the hub 5, here the upper carbon disc 9. The wedging device 19 has an opening 31, arranged on this carbon disc 9, and capable of receiving at least part of the inertial device 33. The opening 31 corresponds in shape to at least part of the inertial device 33, so as to allow the latter to move between its first position and its second position.

[0056] The opening 31 is delimited by a pair of mutually opposite edges, which can further form, for the inertial device 33, its first abutment surface 25 or its second abutment surface 27. Here, one of these edges forms the first abutment surface 25 while the other forms its second abutment surface 27.

[0057] The inertial device 33 may comprise, as here, a central portion or flyweight 21, and a pair of flanges, each of which connects one of the ends of the flyweight 21 to a portion of the blade 7. Here, the flanges each connect one of the ends of the flyweight 21 to a corresponding end of the fork 39 of the blade 7. Here, the flyweight 21 is assembled integrally to each of the flanges, here by screwing. Here, the flyweight 21 is shaped as a spacer for the flanges and the fork 39. Here, the flyweight 21 has a generally cylindrical shape, with an axis generally parallel to the rotor drive plane.

[0058] The opening 31 can form, as here, a rotation guide for the inertial device 33. The opening 31 is in cooperation in shape with one of the flanges, called the inner flange 29, which is engaged in this opening 31. The other of the flanges, called the outer flange 49, is projecting from the hub 5. Here, the opening 31 is shaped as a slot delimited, at one of its ends, by the first stop surface 25, and, at the other of its ends, by the second stop surface 27.

[0059] Here, the inner flange 29 and the outer flange 49 are made of carbon, which reduces the weight of the system. Alternatively, the inner flange 29 and the outer flange 49 can be made of aluminum.

[0060] Here, the blade 7 is assembled in a solid manner to the inner flange 29 and to the outer flange 49, by means of its fork 39.

[0061] Here, the fork 39 has a disc portion 41, which projects from the jaws 11, on the side of the latter opposite the active portion 43 of the blade 7. This disc portion 41 is assembled in a fixed manner to the inner flange 29, here by means of a pair of screws 47. Here, this disc portion 41 has the general shape of a truncated cone, with an axis corresponding to the axis of rotation 37 of the blade 7 relative to the hub 5. This disc portion 41 has a lug 35, which extends along this axis, in the direction of the axis of rotation 3 of the rotor 1. The inner flange 29 has an orifice, corresponding in shape to the lug 35. The inner flange 29 is assembled to the fork 39 by the lug 35 fitting into its orifice.

[0062] The torsion spring 23 is wound around the lug 35. The first branch 51 of the torsion spring 23 is arranged to cooperate with one of the screws 47 when the inertial device 33 moves from its first position to its second position, so as to constrain the torsion spring 23.

[0063] Here, the fork 39 further has a stirrup 59, which projects from its disc portion 41. The stirrup 59 is arranged so as to receive the root 15 of the blade 7. The stirrup 59 and the root 15 of the blade 7 are fixed to each other by screwing. The stirrup 59 is assembled securely to the outer flange 49, here by screwing.

[0064] The wedging device 19 further comprises one or more rolling devices, arranged so as to reduce the friction between the jaws 11 and the blade 7 during the rotation of this blade 7 relative to the hub 5. Here, these rolling devices are arranged so as to reduce the friction between the jaws 11 and the fork 39.

[0065] Here, the wedging device 19 comprises a ball bearing 55, which has an inner ring and an outer ring, mutually in contact and capable of rotating relative to each other. The inner ring is assembled to the stirrup 59 of the blade root 15 while the outer ring is assembled on the jaws 11.

[0066] Here, the wedging device 19 further comprises a needle bearing 57, which has a first washer and a second washer, mutually in contact and capable of rotating relative to each other. The first washer is arranged in abutment against an inner face of the jaws 11 while the second washer is assembled to the disc portion 41 of the fork 39.

[0067] The timing devices 19 of the rotor 1 may be connected to each other, so as to synchronize the positioning of the blades 7 relative to the hub 5. In particular, the timing devices 19 may be connected to each other by means of rods connecting the mutually adjacent inertial devices 33 together. In this way, if one of the timing devices 19 should have a malfunction, the corresponding blade 7 is oriented appropriately by the joint action of the other timing devices 19.

[0068] The invention is not limited to the embodiments described above, but encompasses all variants conceivable by those skilled in the art. In particular, the inertial device of the wedging device may be shaped in a different manner, in particular in relation to the shape of the associated blade. This blade may, for example, have a part of its active portion configured to extend in an offset manner relative to its axis of rotation. This offset portion then contributes to the operation of the inertial device, which makes it possible to reduce the mass of the flyweight thereof, and therefore to reduce the overall mass of the propulsion system.

Claims

Aircraft propulsion system, which comprises a stator and a rotor (1), configured to rotate relative to the stator about an axis (3), the rotor (1) comprising a hub (5) and a blade (7), mounted on the hub (5) so as to be able to pivot between at least a first position and a second position, the rotor (1) further comprising a wedging device (19), capable of moving the blade (7) between its first position and its second position, characterized in that the wedging device (19) comprises an inertial device (33), connected to the blade (7) and arranged so as to move relative to the hub (5) between at least one position close to the axis (3), in which the wedging device (19) constrains the blade (7) in the first position, and a position remote from the axis (3), in which the wedging device (19) constrains the blade (7) in the second position, the wedging device (19) further comprises an elastic member (23),which returns the inertial device (33) to the position close to the axis (3), and the wedging device (19) is configured so that, when the rotational speed of the rotor (1) relative to the stator exceeds a threshold value, the inertial device (33) moves from the position close to the axis to the position far from the axis (3) by centrifugal effect, andthe blade (7) comprises an end portion (39), by means of which the blade (7) is connected to the hub (5), and the inertial device (33) comprises a flyweight (21) and a pair of flanges (29,49), which each connect the flyweight (21) to the end portion (39), the flyweight (21) being shaped as a spacer for the pair of flanges (29,49) and the end portion (39)., System according to claim 1, wherein the inertial device (33) is arranged to pivot relative to the hub (5) between the position close to the axis (3) and the position far from the axis (3). System according to one of claims 1 and 2, in which the wedging device (19) further comprises a stop surface (25, 27) for the inertial device (33), active when the inertial device (33) is in the position close to the axis (3) or in the position far from the axis (3). System according to one of the preceding claims, in which the wedging device (19) comprises an opening (31), capable of receiving at least part of the inertial device (33), and which has an edge, which forms a stop surface (25, 27) for the inertial device (33), which is active when the inertial device (33) is in the position close to the axis (3) or in the position far from the axis (3). System according to one of the preceding claims, in which the wedging device (19) comprises an opening (31), capable of receiving at least part of the inertial device (33), and which has a pair of mutually opposite edges, which form abutment surfaces (25, 27) for the inertial device (33), one being active when the inertial device (33) is in the position close to the axis (3), the other being active when the inertial device (33) is in the position far from the axis (3). System according to one of claims 4 and 5, wherein the inertial device (33) is arranged so as to pivot relative to the hub (5) between the position close to the axis (3) and the position far from the axis (3), the opening (31) being shaped as a rotation guide for the inertial device (33). System according to one of the preceding claims, in which the inertial device (33) and the blade (7) are arranged so as to pivot relative to the hub (5) around the same axis of rotation (37) between the position close to the axis (3), respectively the first position, and the position far from the axis (3), respectively the second position. System according to one of the preceding claims, in which the elastic member (23) is shaped as a torsion spring, wound around at least part of the end part (39), and which has a pair of branches, one of these branches being arranged so as to cooperate with the hub (5), the other of these branches being arranged so as to cooperate with one of the flanges (29) of the inertial device (33). System according to one of the preceding claims, in which the inertial device (33) and the blade (7) are integral with each other. System according to one of the preceding claims, in which the wedging device (19) further comprises a locking element, capable of cooperating with the inertial device (33) so as to maintain the latter in an intermediate position between the position close to the axis (3) and the position far from the axis (3) relative to the hub (5), which corresponds to a position of the blade (7) intermediate between its first position and its second position relative to the hub (5). System according to one of the preceding claims, wherein the rotor (1) comprises an additional blade (7), mounted on the hub (5) so as to be able to pivot between at least a first position and a second position, as well as an additional wedging device (19), capable of moving the additional blade (7) between its first position and its second position, and the wedging device (19) and the additional wedging device (19) are mutually connected so as to synchronize the movement of the blade (7) and the additional blade (7) between their respective first position and second position.

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