RU2796081C2 - Aircraft propulsion system - Google Patents

Abstract

FIELD: aircrafts.

SUBSTANCE: propulsion system (100) for the aircraft includes a rotor (110) and a gondola cowl located around the rotor (110). The gondola cowl is divided into sectors and contains a fixed sector (130a, 130b) and sectors (141a, 141b) retractable in the circumferential (F1, F2) direction relative to the rotation axis (X) of the rotor (110). The retractable sectors comprise the first row of sectors (141a, 142a) telescopically retracting inward or onto said fixed sector (130a), the second row of sectors (141b, 142b) telescopically retracting inward or onto the fixed sector (130a, 130b). Said fixed sector (130a, 130b) has an angular dimension around said axis (X) less than or equal to 90°.

EFFECT: improvement of aerodynamic and acoustic characteristics of aircraft is achieved.

15 cl, 16 dwg

Description

The field of technology to which the invention belongs

The present invention relates to the field of aircraft propulsion systems. In particular, it concerns a propulsion system with a retractable nacelle fairing.

State of the art

The prior art is represented, in particular, by documents CH-A2-711721, US-A1-2006/284007, US-A1-2016/023754 and WO-A1-2017/154552.

The aircraft propulsion system comprises at least one rotor or propeller having a plurality of blades mounted on a rotating shaft.

There are aircraft, in particular vertical take-off and landing (VTOL or VTOL - short for Vertical Take-Off and Landing in English), having propulsion systems with simple rotors when they contain only one rotor, or with rotors of the opposite rotation, when they contain rotors combined in pairs and rotating in opposite directions.

These propulsion systems are either canned rotor systems (with the rotor surrounded by an annular nacelle fairing) or open rotor systems, whereby the propulsion systems and in particular the rotors (open or canned) can be mounted on a rotary shaft providing orientation of the propulsion systems. and hence the rotors between a vertical position and a horizontal position, such as a vertical orientation for vertical takeoff or landing, and a horizontal orientation for normal flight or aircraft mode.

Hooded rotors have the following advantages:

- a significant reduction in the sound signature of the rotor with direct radiation;

- protection of rotor blades against surrounding obstacles;

- improvement of rotor performance, in particular during the hover mode of the aircraft or at low speed.

Indeed, the cowled nacelle provides the rotor with additional thrust in hover, during takeoff or at low speed, due to the influence of the cowled nacelle on the airflow at the outlet of the rotor relative to the direction of passage of this airflow on the cowled nacelle, also called the flow tube. In particular, in the absence of a nacelle fairing, in the case of an open rotor, the airflow at the outlet of the rotor undergoes a natural contraction towards the inside. In other words, the diameter of the flow pipe decreases towards the outlet, reaching a diameter equal to half the rotor section.

On the other hand, in the case of a shrouded rotor, the outlet section of the nacelle fairing determines the shape of the airflow tube, namely a substantially constant cylindrical shape at the outlet of the nacelle fairing, which prevents its natural narrowing.

The traction balance depends on the outlet section of the nacelle fairing, and the larger the outlet section of the nacelle fairing, the greater the traction balance. Indeed, the thrust generated in the presence of the nacelle fairing is generated at the level of the leading edge of said fairing due to the local rarefaction associated with the passage of the air flow around the nacelle fairing. The greater the flow rate of air entering the propulsion system, in other words, the greater the outlet section of the nacelle fairing, the stronger this rarefaction and, consequently, the greater the generated thrust.

However, at high speeds, the traction efficiency of the canned rotor decreases. Indeed, as the forward speed of the aircraft increases, the efficiency of the cowled rotor decreases due to the rapid increase in drag caused by the presence of the nacelle fairing. Thus, the traction efficiency decreases depending on the rotation mode and on the size of the rotor.

In the case of a shrouded rotor, noise emission masking and safety at the perimeter of the rotor are favored at the expense of propulsion efficiency in flight at the cruising speed of the aircraft, i.e. at high speed.

On the other hand, in the case of an open rotor propulsion system (without a nacelle fairing around the rotor), there is no drag that could be created by a nacelle fairing, so the propulsion efficiency is optimal, providing, in particular, higher flight altitudes or providing a longer flight duration. .

However, the absence of a fairing around the rotors results in more noise emissions and therefore a significant negative noise impact. In addition, in this case, the rotor blades are not protected, which increases the risk of collision with an obstacle and, therefore, reduces the safety of the rotor, which is, in particular, a risk during phases of flight near the ground or landing infrastructure. Finally, in the absence of a nacelle fairing for an open rotor, the thrust effect of the nacelle fairing in hover mode or at low speed is lost.

Thus, open rotors and canned rotors have additional advantages. Indeed, it is important to be able to combine the advantage of the thrust effect of the nacelle fairing and the reduction of noise during the low speed or hover phases of flight by equipping the propulsion system with a nacelle fairing acting as a shield over the rotors and the advantage of an open rotor propulsion system having better Efficiency during higher speed flight phases or when the flight environment does not force rotor protection or noise requirements.

Currently, there are gas turbine engines having an adjustable hood at the inlet of the nacelle fairing surrounding the rotor of the gas turbine engine (in the direction of the air flow during operation of the gas turbine engine). This hood is axially movable relative to the longitudinal axis of the gas turbine engine to change the inlet geometry of the nacelle fairing and thus increase thrust and reduce noise. The bonnet comprises a plurality of segments which may be positioned radially outward at the inlet of the nacelle fairing and retracted relative to the longitudinal axis of the gas turbine engine so that at low speed during takeoffs or during landings of an aircraft equipped with such a gas turbine engine, the hood is fully extended, while at high speed, the hood is completely retracted.

This solution, while meeting the challenge of optimizing the acoustics of the rotor and the aerodynamic flight characteristics of the aircraft, does not solve all of the aforementioned problems, since the nacelle with the fairing remains around the rotor, thus creating additional drag at high speed.

Rotor nacelle fairings for aircraft have also been proposed, partially retractable in a circumferential direction around the rotor. Such a nacelle fairing comprises a fixed wall and a movable wall movable relative to the fixed wall in order to partially open the rotor, in particular during landing phases of the aircraft, in order to limit the clearance of the rotor, with the open part of the rotor facing the ground. However, the nacelle cowl retracting corner portion remains small with respect to the nacelle fairing corner portion which remains stationary around the rotor, so this solution also fails to solve the above problems.

Therefore, there is a need for a simple and effective solution to the above problems.

The present invention aims to provide a solution to easily and quickly adapt the propulsion system of aircraft in order to optimize their aerodynamic and acoustic performance depending on the phases of flight and the environment in which they move, while ensuring the safety of the rotors.

Disclosure of invention

To do this, the invention proposes a propulsion system for an aircraft, containing at least one rotor and a nacelle having a fairing located around said at least one rotor, this nacelle fairing is divided into sectors and contains at least one fixed sector and sectors retractable in the circumferential direction relative to the axis of rotation of the rotor, characterized in that the retractable sectors contain at least one row of sectors, telescopically retractable inside or on the said at least one fixed sector, and at least one second row of sectors, telescopically retractable inside or on the said at least one fixed sector, wherein said at least one fixed sector has an angular dimension around said axis less than or equal to 90°.

Thus, the claimed propulsion system allows, depending on the needs of the aircraft, to simply and quickly use either a cowled rotor or an open rotor.

According to an exemplary embodiment, the retractable sectors of the first row of sectors can retract telescopically one inside the other or inside said at least one fixed sector, and the retractable sectors of the second row of sectors can retract telescopically one inside the other or inside said at least one fixed sector.

Preferably, the retractable sectors are configured to trigger their retract either automatically depending on predetermined flight conditions of the aircraft, or upon a specific user command.

Preferably, the retractable sectors have an overall tubular shape and each have transverse dimensions that decrease from one circumferential end to the opposite circumferential end, allowing them to easily fit into each other in the retracted position and simultaneously telescopically move during their deployment or retraction. This truncated end shape also provides a seal between two adjacent sectors.

Preferably, each of the rows of sectors comprises:

- end sector; And

- at least one intermediate sector;

wherein the end sector of the first row of sectors comprises end guiding and locking means configured to interact with complementary end guiding and locking means equipped with the end sector of the second row of sectors to lock the nacelle fairing in the closed position.

Thus, the nacelle fairing is securely held in the deployed position.

Preferably, at least some of the sectors contain sealing means, for example, at the level of their circumferential ends, made with the possibility of ensuring tightness with the adjacent sector or adjacent sectors.

These sealing means, in addition to ensuring the tightness of the nacelle fairing, ensure the supply of hot air to the interior of the sectors to combat icing, if necessary.

Preferably, the propulsion system comprises a device for activating the deployment or retraction of sectors of each row, this device comprising a bi-directional system with a yoke for telescopic deployment and retraction of said sectors, from the fixed sector or into the fixed sector or onto the fixed sector.

According to a preferred exemplary embodiment, the bi-directional drive system comprises gears and rack segments driven by a single electric motor, wherein the bi-directional system is configured to engage the pinion with at least one end sector gear rack, then subsequently engaging the gears with the racks. of each intermediate sector, from one to another, from the fixed sector in the case of deploying the nacelle fairing or to the fixed sector in the case of retracting the nacelle fairing.

Preferably, the sectors comprise at least one yoke segment having a U-shaped cross section.

Thus, they can be deployed in the circumferential direction, ensuring good deployment of the nacelle fairing also in the circumferential direction.

The subject of the present invention is also a method for controlling the fairing of the nacelle of the claimed propulsion system for an aircraft from the open, respectively closed position of the fairing of said nacelle. characterized in that the retractable sectors are telescopically deployed, respectively go into each other in the circumferential direction relative to the axis of rotation of the rotor, from the said at least one fixed sector or into it or onto it.

According to an exemplary embodiment of the claimed control method, deploying the nacelle fairing from the nacelle fairing opening position comprises the following steps:

- detecting a predetermined flight condition for automatic control or manual control of the closing of the nacelle fairing;

- transmitting a request for deploying sectors to the control and management unit;

- command to extend the bidirectional drive system to deploy the nacelle fairing in the circumferential direction around the rotor from the fixed sector or each fixed sector;

- blocking the fairing of the nacelle in the deployed position by means of blocking the end sector or each end sector;

- detect active lock conditions in the deployed position and notify the user about them.

Preferably, the predetermined condition for the automatic control of closing the nacelle fairing is an aircraft hovering phase or an aircraft speed less than or equal to 180 km/h.

According to another exemplary embodiment of the claimed control method, retracting the nacelle fairing from the nacelle fairing closing position comprises the following steps:

- detecting a predetermined flight condition for automatic control or manual control of the opening of the nacelle fairing;

- transmitting a request for removing sectors to the monitoring and control unit;

- submit a shortening command to the bidirectional drive system to retract the nacelle fairing in the circumferential direction around the rotor until the sectors completely overlap each other in the fixed sector or each fixed sector;

- block the fairing of the gondola in the retracted position;

- detect active interlock conditions in the retracted position and notify the user about them.

Preferably, the predetermined condition for the automatic control of the opening of the nacelle fairing is the speed of the aircraft in excess of 180 km/h.

As stated above, transitioning a propulsion system to an open rotor or canopied rotor configuration is simple, quick and safe.

Finally, the object of the present invention is an aircraft, characterized in that it contains at least one propulsion system having any of the above features, while the propulsion system is installed with the possibility of rotation on the aircraft by means of a rotary shaft, remote or through relative to the rotor.

Thus, the aircraft can easily change from the classic mode to the vertical takeoff or landing mode, easily adapting to the environment in which it must fly.

Brief description of the figures

Other features and advantages of the invention will become more apparent from the following detailed description with reference to the accompanying drawings, in which:

Fig. 1 is a schematic perspective view of a first exemplary embodiment of the claimed propulsion system, showing the fairing nacelle in a deployed position with the propulsion system in a horizontal position.

Fig. 2 is a view similar to FIG. 1 showing the propulsion system in a vertical position.

Fig. 3 is a view similar to FIG. 1 showing the nacelle fairing during retraction.

Fig. 4 is a view similar to FIG. 1, where the nacelle fairing is almost completely retracted.

Fig. 5 is a schematic view of an aircraft equipped with the claimed propulsion systems, the nacelles of which are shown with the fairing in a deployed position around the rotors.

Fig. 6 is a view similar to FIG. 5, where some nacelles are shown with their fairings in the retracted position and others are shown with their fairings in the deployed position.

Fig. 7 is a schematic perspective view of a second exemplary embodiment of the claimed propulsion system, showing the fairing nacelle in a deployed position, with the propulsion system in a horizontal position.

Fig. 8 is a view similar to FIG. 7, where the nacelle fairing is almost completely retracted.

Fig. 9a is a schematic view showing two adjacent sectors of a nacelle fairing fitting into each other.

Fig. 9b is a detailed unsized sectional view showing the drive collars of two adjacent sectors of the nacelle fairing.

Fig. 10 is a schematic detailed view of an exemplary embodiment of the end sector.

Fig. 11 is a schematic detailed view of a set of nacelle fairing sectors and their drive system in accordance with the invention.

Fig. 12 is a perspective view of a set of yoke segments of the inventive drive system in a deployed position.

Fig. 13 is a partial detailed front sectional view showing the yoke segments of the claimed drive system in the retracted position.

Fig. 14 is a detailed view of the gear system with the drive system play shown in FIG. eleven.

Fig. 15 is a detailed view of a gear/rack rack tooth offset device according to the invention.

Detailed description

In this application, the terms "distal" and "proximal" are used to denote the position of the sectors of each row with respect to the fixed sector of that row. The terms "internal" and "external" are used to refer to the constituent elements of each sector.

As a rule, the propulsion system includes:

- gondola;

- engine and its control and monitoring system;

- and, in the case of propeller or rotor propulsion, the propeller or rotor(s).

The gondola is an element that allows the engine to be integrated into the aircraft, and it contains:

- fairings (allowing you to close the engine, cowl the rotors, trap air in the form of a stream during the operation of the aircraft, create a thrust effect, reverse thrust on turbojet engines, ...);

- equipment installed on the engine (such as the engine casing, which combines electrical, hydraulic, pneumatic networks, known by the abbreviation EBU for the English Engine Build-up Unit); And

- mounting systems on the aircraft.

In FIG. 1-4 show in simplified form a first embodiment of a propulsion system 100 for an aircraft in accordance with the invention.

The propulsion system 100 comprises in this case at least one rotor 110 and a nacelle fairing 120 disposed around said at least one rotor 110. The propulsion system 100 can be fixedly mounted on the aircraft 1. The propulsion system 100 can also be mounted on a rotary shaft 10, which is placed relative to the axis of rotation X of the rotor 110. The rotary shaft 10 is fixed by any means on the propulsion system 100 on the one hand, and on the aircraft 1 on the other hand, and provides orientation of the propulsion system 100 on the aircraft 1, allowing the propulsion system 100 to rotate about the longitudinal axis L1 of the rotary shaft 10 in the direction of the arrow F by known drives between the horizontal position shown in FIG. 1 and the vertical position shown in FIG. 2. This rotation allows the aircraft 1 to change from classic airplane mode to runway or helicopter mode.

The rotor 110 of the propulsion system 100 is connected to the aircraft 1 via a rack 111 on which a motor 112, such as an electric motor, drives the rotor 110 through a power shaft, as is known per se. According to the non-limiting example shown, each rotor 110 includes two blades 113.

The nacelle fairing 120 is divided into a plurality of sectors. According to the example shown in FIG. 1-4, the nacelle fairing 120 is divided into eight sectors divided into two rows, with the sectors belonging to the first row being indicated by the letter “a” and the sectors belonging to the second row being indicated by the letter “b”.

Thus, the nacelle fairing 120 contains:

- two fixed sectors 130a, 130b;

- four intermediate sectors 141a, 142a, 141b, 142b; And

- two end sectors 150a, 150b.

The sectors are thus arranged in rows, with the first row containing a fixed sector 130a, two intermediate sectors 141a, 142a and an end sector 150a, and the second row containing a fixed sector 130b, two intermediate sectors 141b, 142b and an end sector 150b. The first row and the second row are configured to interact with each other so as to form the fairing 120 of the nacelle.

The fairing 120 of the nacelle of the propulsion system 100 may be mounted directly on the wing or fuselage section of the aircraft 1 or on the rotary shaft 10 via fixed sectors 130a, 130b.

The intermediate sectors and end sectors are retractable in a circumferential direction relative to the rotational axis X of the rotor 110. In particular, according to the first embodiment, the end sector 150a can be telescopically retracted into the distal intermediate sector 142a, which, in turn, can be telescopically retracted into the proximal intermediate sector 141a, which in turn can be telescopically retracted inside the fixed sector 130a. Similarly, end sector 150b can be telescopically retractable into distal intermediate sector 142b, which in turn can be telescopically retractable into proximal intermediate sector 141b, which in turn can be telescopically retractable into fixed sector 130b.

According to another (not shown) embodiment, the sectors can be retracted on top of each other and onto the fixed sector. In other words, the end sector 150a can be telescopically retracted onto the distal intermediate sector 142a, which, in turn, can be telescopically retracted onto the proximal intermediate sector 141a, which, in turn, can be telescopically retracted onto the stationary sector 130a. Similarly, end sector 150b can be telescopically retracted onto distal intermediate sector 142b, which in turn can be telescopically retracted onto proximal intermediate sector 141b, which in turn can be telescopically retracted onto fixed sector 130b.

In the following text of this application, retraction is presented (with reference to the drawings) according to an embodiment in which the retractable sectors are made with the possibility of telescopic retraction into each other from the most distal to the most proximal, then into a fixed sector, although this example is not restrictive.

It is possible to provide only one fixed sector 130ab, common to rows “a” and “b”, instead of two fixed sectors 130a and 130b, in which case the fairing 120 of the nacelle will be divided into seven sectors.

In this way, the nacelle fairing 120 can transition from a fully deployed position around the rotor shown in FIG. 1 and 2 to the fully retracted position shown in FIG. 4, in which case the rotor 110 can be equated to an open rotor. Indeed, in this example, the sum of the angular dimensions of the fixed sectors 130a, 130b around the X-axis of rotation of the rotor 110 is less than or equal to 90°, so that in the retracted position of the nacelle fairing 120, the rotor 110 of the propulsion system 100 is similar to an open rotor.

In FIG. 5 and 6 show an aircraft 1 comprising four propulsion systems 100 with twin counter-rotating rotors 110. In FIG. 5, all propulsion systems 100 are shown with the nacelle fairing 120 fully deployed around the rotors 110. In FIG. 6, two propulsion systems 100 are shown with nacelle fairings 120 fully deployed around their respective rotors 110, while two other propulsion systems 100 are shown with nacelle fairings 120 whose retractable sectors are fully retracted within fixed sectors 130ab.

In this case, the aircraft 1 is shown in the classic mode, that is, in the forward flight mode or in the "airplane" mode. However, the rotary shaft 10 allows the aircraft 1 to enter the vertical flight mode, providing lift to the aircraft.

In the examples shown, some of the propulsion systems 100 are mounted on the upper surface of the wings of the aircraft 1. However, these propulsion systems 100 may also be mounted on the inner surface of the wings of the aircraft.

In FIG. 7 and 8 show a second embodiment of an aircraft propulsion system 200 in accordance with the invention.

Similar to the first embodiment, the propulsion system 200 comprises in this case at least one rotor 210 and a nacelle fairing 220 disposed around said at least one rotor 210. The propulsion system 200 may be fixedly mounted on the aircraft. The propulsion system 200 can also be mounted on a rotary shaft 20 passing through the rotor 210 perpendicular to the axis of rotation X of the rotor 210. The rotary shaft 20 is fixed by any means to the propulsion system 200 on the one hand, and on the aircraft 1 on the other hand. , and ensures the orientation of the propulsion system 200 on the aircraft 1, allowing the propulsion system 200 to rotate about the longitudinal axis L2 of the rotary shaft 20 in the direction of the arrow F by known actuators between the horizontal position shown in FIG. 7 or 8, and a vertical position (not shown). This rotation allows the aircraft to transition from classic airplane mode to runway or helicopter mode.

The rotor 210 of the propulsion system 200 is connected to the aircraft by means of a rack 211 on which is mounted a motor 212, such as an electric motor, driving the rotor 210 through a power shaft, as is known per se. According to the illustrated embodiment, the leg 211 of the rotor 210 coincides with the rotary shaft 20. According to the non-limiting example shown, each rotor 210 includes two blades 213.

The nacelle fairing 220 is divided into a plurality of sectors. According to the example shown in FIG. 7 and 8, the nacelle fairing 220 is divided into ten sectors divided into four rows, which are labeled “a”, “b”, “c”, and “d”.

Thus, the nacelle fairing 220 comprises:

- two fixed sectors 230ad, 230bc;

- four intermediate sectors 240a, 240b, 240c and 240d; And

- four end sectors 250a, 250b, 250c and 250d.

The sectors are arranged in rows, with the first row containing a portion of the fixed sector 230ad, an intermediate sector 240a and an end sector 250a; the second row contains a portion of the fixed sector 230bc, the intermediate sector 240b and the end sector 250b; the third row comprises a fixed sector portion 230bc, an intermediate sector 240c, and an end sector 250c, and the fourth row comprises a fixed sector portion 230ad, an intermediate sector 240d, and an end sector 250d. The four rows are configured to interact in pairs to form a nacelle fairing 220.

In this embodiment, fixed sector 230ad is common to rows of sectors “a” and “d”, and fixed sector 230bc is common to rows of sectors “b” and “c”. It is possible to provide that each row has its own fixed sector, in which case the fairing 220 of the nacelle will be divided into twelve sectors.

The fairing 220 of the nacelle of the propulsion system 200 may be mounted directly on the wing or fuselage section of the aircraft or on the rotary shaft 20 via its fixed sectors 230ad, 230bc.

The intermediate sectors and end sectors can be retracted in a circumferential direction relative to the axis of rotation X of the rotor 210. In particular, according to the first non-limiting embodiment, the end sector 250a can be telescopically retracted inside the intermediate sector 240a, which, in turn, can be telescopically retracted inside the fixed sector 230ad. Similarly, the end sector 250b can be telescopically retracted inside the intermediate sector 240b, which, in turn, can be telescopically retracted inside the fixed sector 230bc; the end sector 250c can be telescopically retracted inside the intermediate sector 240c, which, in turn, can be telescopically retracted inside the fixed sector 230bc; and the end sector 250d can be telescopically retracted into the intermediate sector 240d, which in turn can be telescopically retracted into the fixed sector 230ad.

As mentioned above, it is possible to provide another embodiment, not shown in the figures, in which the retractable sectors 240a and 250d-240d, respectively 250b-240b and 250c-240c, are telescopically retracted onto the fixed sectors 230ad, respectively 230bc.

In this way, the nacelle fairing 220 can transition from a fully deployed position around the rotor shown in FIG. 7 to the fully retracted position shown in FIG. 8, in which case the rotor 210 can be equated to an open rotor. Indeed, in this example, the sum of the angular dimensions of the fixed sectors 230ad, 230bc around the X axis of rotation of the rotor 210 is less than or equal to 90°, so in the retracted position of the nacelle fairing 220, the rotor 210 of the propulsion system 200 is similar to an open rotor.

For ease of understanding, in the following text of the present application, common to the two above-mentioned embodiments, the fixed sectors will be indicated by the position 30, the intermediate sectors will be indicated by the position 40, and the end sectors will be indicated by the position 50.

The number of sectors forming the nacelle fairing 120, 220 can be selected depending on aerodynamic and mechanical requirements.

In FIG. 9a, 9b and 10 show retractable sectors. In particular, in FIG. 2a shows two intermediate sectors 40a, 40b, FIG. 9b is a detailed view of FIG. 9a and FIG. 10 shows the end sector 50.

As noted above, the figures illustrate an embodiment in which the retractable sectors 50, 40a, 40c are configured to retract into each other from the most distal to the most proximal and into the fixed sector 30. However, the above features can be adapted for an embodiment in which retractable sectors are made with the ability to retract each other from the most distal to the most proximal and onto the fixed sector.

Intermediate 40A, 40b and end 50 retractable sectors, as well as the fixed sector 30 have a common tubular shape (that is, have an internal cavity), having a main longitudinal axis and cross-sections.

The sectors 30, 40a, 40b and 50 each have transverse dimensions that decrease from the so-called proximal circumferential end 30', 40a', 40b', 50' to the opposite so-called distal circumferential end 30”, 40a”, 40b”, 50". In other words, the section of the proximal circumferential end 30”, 40a”, 40b”, 50” of sectors 30, 40a, 40b, 50 is larger than the section of the distal circumferential end 30', 40a', 40b', 50' of sectors 30, 40a, 40b, 50, which gives them a truncated cone shape, allowing them to easily fit into each other in the retracted position. Accordingly, in an embodiment in which the retractable sectors overlap each other and onto the fixed sector, the sectors each have transverse dimensions that decrease from the so-called distal circumferential end to the opposite so-called proximal circumferential end, which gives them the shape of a truncated cone, allowing them to easily go over each other in the retracted position.

To ensure such a landing, each sector has a size smaller than the size of the sector into which it must enter. Accordingly, each sector has dimensions that exceed the dimensions of the sector on which it should be planted. For example, according to the first embodiment, the distal intermediate sector 40b is smaller than the proximal intermediate sector 40a. All retractable sectors 40a, 40b, 50 are designed to fit into the fixed sector 30, and therefore this fixed sector 30 is sized to contain all other sectors in the retracted position. Therefore, the end sector 50 is the sector that has the smallest dimensions.

The shape of the sectors 30, 40a, 40b and 50 in the form of a truncated cone ensures that they follow each other telescopically during their deployment or retraction. The term "telescopic" means that each distal sector enters, respectively deploys, into the adjacent proximal sector, respectively from the adjacent proximal sector by sliding the distal sector into the proximal sector, respectively by sliding the distal sector out of the proximal sector.

The circumferential ends of each sector have a collar (FIG. 9b) to connect two adjacent sectors to each other during deployment or retraction operations of the fairing 120, 220 of the nacelle. For example, the intermediate sector 40a contains on its inner surface at the level of its distal circumferential end 40a" an annular collar 41a, and the intermediate sector 40b contains on its inner surface at the level of its proximal circumferential end 40b' an annular collar 41b, while the collar 41a of sector 40a is made with the ability to interact with the shoulder 41b sector 40b to ensure the connection of the two sectors 40a, 40b between them during deployment or retraction of the fairing 120, 220 gondola. This connection can be made by any other suitable means.

The retractable sectors 40a, 40b, 50 are configured to be deployed or retracted automatically according to the flight conditions of the aircraft 1 or by a specific user action on command, as will be described below.

The truncated cone shape of the sectors 30, 40a, 40b and 50 also provides a seal between two adjacent sectors.

Preferably, the sectors 30, 40a, 40b and 50 have an airfoil adapted to the passage of the air flow during operation of the propulsion system 100, 200.

Since the sectors 30, 40a, 40b and 50 form the corner section of the fairing 120, 220 of the annular nacelle, they also have a curved shape.

Sectors 30, 40a, 40b and 50 are made of structural material of sufficient strength, such as, for example, aluminum alloy or carbon fiber composite. Preferably, the structure forming the sectors 30, 40a, 40b and 50 may also have acoustic absorption properties to reduce the noise of the rotor 110, 210 when the nacelle fairing 120, 220 is deployed.

At its distal end, the end sector 50 has a platform 51 configured to rest on the end sector platform of another row of sectors to ensure contact between the two rows of sectors during the deployment of the fairing 120, 220 of the nacelle. In order to guide the end sectors 50 of the two rows as they come into contact at the end of the deployment, each end sector 50 may also comprise an end direction device 52. For example, this end direction device 52 may include a pin located on the end sector 50 of one of the rows and configured to interact with a cutout made on the end sector 50 of the other of the rows.

The end sector 50 of the first row of sectors also contains locking means 53 configured to interact with the complementary locking means that the end sector of the second row of sectors is equipped with, such as, for example, an electrically controlled electromagnetic latch to lock the nacelle fairing in the closed position, as well as to improve tightness and aerodynamic fairing 120, nacelle 220.

However, this embodiment assumes the presence of wires inside the nacelle fairing 120, 220, for which it is necessary to provide winding or unwinding systems simultaneously with the deployment and retraction movements of the nacelle fairing 120, 220, or to provide a set of electrical tracks performed directly in the constituent elements of the nacelle fairing 120, 220 ( for example, in gear racks, which will be described below).

Thus, another preferred embodiment of the locking means 53 is a mechanical latch, in which the application of a first push secures the lock and a second push unlocks.

For obvious safety reasons, it is necessary to ensure that the fairing 120, 220 of the nacelle is well locked in the deployed position. Thus, the propulsion system 100, 200 may include a lock-in-deploy control device for the nacelle fairing 120, 220, such as an analog switch, for example. This control device may preferably be configured to alert the user or computing device of the active locking of the fairing 120, 220 of the nacelle in the deployed position. Similarly, if the analog switch detects a bad locking of the nacelle fairing 120, 220 in the deployed position, an alarm signal (eg, by means of an audible or light signal) can be transmitted to the user of the aircraft, for example, on the instrument panel of the cockpit of the aircraft.

In order to improve the tightness of the nacelle fairing, and in particular the tightness between two adjacent sectors, at least some of these sectors 30, 40a, 40b and 50 are also equipped with sealing means (not shown), for example, at the level of their circumferential ends.

These sealing means are, for example, brush pads located on the outer surface of each sector 30, 40a, 40b and 50 at the level of their circumferential ends and configured to interact with the inner surface of each sector 30, 40a, 40b and 50, which is opposite these brush pads during the deployment or retraction of the fairing 120, 220 gondola. This solution is advantageous because, in addition to sealing with the adjacent sector or sectors, these brush pads do not interfere with the supply of hot air to the interior of the tubular sectors 30, 40a, 40b and 50 to de-ic them if necessary.

The tightness can also be provided by any other means or by precise fitting of sectors 30, 40a, 40b and 50, but this solution is not preferred.

In order to allow the sectors 30, 40a, 40b and 50 to be telescopically deployed or retracted by sequentially pairing the sectors 30, 40a, 40b and 50 into each other, each row of sectors 30, 40a, 40b and 50 is equipped with a drive device, such as a bi-directional drive system 2 with a jack-type link with a gear rack. In FIG. 11-15 show such a bi-directional drive system in detail for fairing 120, 220 comprising eight sectors distributed in two rows of four sectors 30, 40a, 40b, 50 in this example.

The bi-directional drive system 2 comprises a plurality of gears 3a, 3b, 3c and a plurality of rack segments 4a, 4b, 4c connected respectively to the link segments 6a, 6b, 6c.

Pairs of pinion-toothed rack are driven by one electric motor 5.

As shown in FIG. 11 and 14, the rack 4a of the end sector 50 has simple teeth and is designed to cooperate with a single gear 3a. On the other hand, the rack 4b of the distal intermediate sector 40a has double teeth and is designed to cooperate with two gears 3b. Similarly, the rack 4c of the proximal intermediate sector 40b has double teeth and is designed to interact with two gears 3c.

The bi-directional drive system 2 is configured to be located in the internal cavities of the tubular sectors 30, 40a, 40b and 50. The yoke segment 6a is connected to the end sector 50. The yoke segment 6b is connected to the distal end sector 40a. Segment 6c of the wings is connected to the proximal end sector 40b. The last gate segment 6d is associated with the fixed sector 30. However, several gate segments may serve the same sector.

As shown in FIG. 11, segments 6a, 6b, 6c, 6d of the wings are concentric. They have a U-shaped cross-section and are curved so as to follow the curved shape of the sectors 30, 40a, 40b and 50. sliding into each other.

Preferably, the yoke segments 6a, 6b, 6c, 6d can be sized to provide mechanical strength to the fairing 120, 220 in all configurations when subjected to aerodynamic, gravitational, and dynamic forces.

Preferably, the surfaces of these yoke segments moving relative to each other may have a self-lubricating coating to prevent the risk of jamming or excessive wear.

Segments 4a, 4b, 4c, 4d of the toothed rack are sized and made in such a way as to go into each other in pairs by sliding in each other, like sectors 30, 40a, 40b and 50.

The bi-directional system 2 is sized and configured to avoid any contact with the rotors 110, 210 during deployment or retraction of the nacelle fairing 120, 220.

The bi-directional system 2 is configured to drive the gears 3a, 3b and 3c connected in rotation to the electric motor 5 via the same shaft. The gear 3a of the end sector 50 engages with the rack segment 4a to move the respective linkage segment 6a, then sequentially with the gears of each intermediate sector 40a, 40b from one to the other, from the most distal to the most proximal from the fixed sector 30 in the case of deploying the fairing 120, 220 nacelles or to the fixed sector 30 in the case of retracting the fairing 120, 220 of the nacelle. In other words, the gear of the distal intermediate sector 40b engages with the rack segment 4b to move the corresponding yoke segment 6b, then the gear 3c of the proximal intermediate sector 40a engages with the rack segment 4c to move the corresponding yoke segment 6c.

Segment 6d scenes associated with the fixed sector 30, but not connected to any rack, remains stationary.

The bi-directional drive system 2 also comprises means 7b, 7c, 7d for locking in the deployed position the yoke segments 6a, 6b, 6c and hence the retractable sectors 40a, 40b, 50. These locking means include, for example, mechanical means comprising two elements , made with the ability to interact (like a cam and a latch or a pin and a cutout) and located, in the case of one of the elements, at the proximal end of the segments 4a, 4b, 4c of the rack and, in the case of the other of the elements, at the distal end of the segments 6b, 6c, 6d backstage, which allows you to mechanically connect or disconnect the rack segments associated with adjacent sectors. These locking means 7b, 7c, 7d may be of the electromechanical type.

The deployment and retraction of the gate segments 6a, 6b, 6c, 6d and hence the sectors 30, 40a, 40b, 50 is carried out sequentially by successively blocking adjacent segments by means of blocking devices 7b, 7c, 7d.

Thus, during the deployment of the sectors 30, 40a, 40b, 50 around the rotors 110, 220, the electric motor 5 rotates in the first direction and drives the set of gears 3a, 3b, 3c. In the first stage, the pinion 3a engages with the teeth of the rack segment 4a to move the respective yoke segment 6a out of the yoke segment 6b until the yoke segment 6a is connected to the yoke segment 6b by the locking means 7b. The gears 3b then engage with the teeth of the rack segment 4b to move the coupled yoke segments 6a and 6b, and specifically move the yoke segment 6b outside of the yoke segment 6c until the yoke segment 6b is connected to the yoke segment 6c by the locking means 7c. Finally, the gears 3c mesh with the teeth of the rack segment 4c to move the connected yoke segments 6a, 6b and 6c and in particular move the yoke segment 6c outside of the yoke segment 6d until the yoke segment 6c is connected to the yoke segment 6d by means 7d blocking.

Similarly, while retracting the sectors 30, 40a, 40b, 50 around the rotors 110, 210, the electric motor 5 rotates in a second direction opposite to the first direction and drives the set of gears 3a, 3b, 3c. In a first step, the locking means 7d is unlocked and the gears 3c are engaged with the teeth of the rack segment 4c to move the yoke segments 6a, 6b and 6c connected by the locking means 7b and 7c until the yoke segment 6c enters the yoke segment 6d. The locking means 7c is then unlocked and the gears 3b mesh with the teeth of the yoke segment 4b to move the yoke segments 6a and 6b connected by the locking means 7b until the yoke segment 6b enters the yoke segment 6c. Finally, the locking means 7b is released and the gear 3a engages with the teeth of the rack segment 4a to move the yoke segment 6a until the yoke segment 6a enters the yoke segment 6b.

The gears 3a, 3b, 3c can advantageously comprise a known tooth offset sampling system 8, which allows only one rotation shaft to be provided for all the gears 3a, 3b and 3c. For example, the system 8 sampling the displacement of the teeth includes cotter pins, going into the stop position in the grooves made in the gears 3a, 3b and 3c.

The deployment and retraction of the sectors around the rotors 110, 210 can also be carried out using other methods, for example, using special pneumatic systems.

Thus, deployment of the fairing 120, 220 of the nacelle of the propulsion system 100, 200 from the opening position of the fairing 120, 220 of the nacelle (in other words, when the retractable sectors 40a, 40b and 50 of the fairing 120, 220 of the nacelle are completely in the fixed sectors 30) can occur either manually command, or automatically upon detection of a predetermined flight condition requiring the propulsion system 100, 200 to transition from an open rotor configuration to a shrouded rotor configuration. Indeed, if it is necessary to reduce the sound impact as the aircraft 1 flies over populated areas, or if the environment contains obstacles that could be dangerous to the rotors, the user can manually activate the deployment of the nacelle fairing 120, 220. In automatic mode, the deployment of the nacelle fairing 120, 220 may be triggered if a hover phase is detected, in other words, if the aircraft 1 is stationary in the air under the action of lift without support and support, or if a low speed of the aircraft 1 is detected, then there is a time when nacelle fairing thrust should be preferred. Closing of the fairing 120, 220 of the nacelle can occur automatically if the speed of the aircraft 1 is less than or equal to 180 km/h.

Thus, when such a manual command is given, or when such a condition is detected, a deployment request for sectors 40a, 40b and 50 is sent to the control unit that controls the extension of the bi-directional drive system 2 to deploy the nacelle fairing 120, 220.

The gear-rack pairs 4a-4a, 4b-4b and 3c-4c are driven as described above.

Therefore, the sectors 40a, 40b, 50 are deployed in the circumferential direction around the rotor 110, 210 (in the direction of the arrows F1 in Fig. 1-4 and 7 and 8) from the end sector 50, which slides beyond the distal intermediate sector 40a, then the distal intermediate sector 40a is slid out of proximal intermediate sector 40b and finally proximal intermediate sector 40b is slid out of fixed sector 30.

The retractable sectors are deployed in this way until the contact of the end sectors 50 of each row of sectors, which are made with the possibility of pairwise interaction. At the end of the deployment stroke, the guide means 52 of the end sectors 50 direct the latter to bring their respective platforms 51 against each other. The locking means 53 of each end sector 50 are then actuated to lock the nacelle fairing 120, 220 in the closing position. In this case, the rotor 110, 210 becomes a canned rotor.

Similarly, the retraction of the nacelle fairing 120, 220 of the propulsion system 100, 200 from the closing position of the nacelle fairing 120, 220 (in other words, when the nacelle fairing is fully deployed around the rotor 110, 210) can occur either by a manual command or automatically upon detection of a predetermined flight conditions requiring the transition of the propulsion system 100, 200 from a cowled to an open rotor configuration, for example, when a high speed of the aircraft 1 is detected, i.e., propulsion efficiency should be preferred. According to an exemplary embodiment, retracting or opening the fairing 120, 220 of the nacelle can take place automatically if the speed of the aircraft 1 exceeds 180 km/h.

Thus, upon detection of such a manual command or such a condition, the locking means 53 of the end sectors 50 are released to ensure the separation of the rows of sectors that were previously associated with their respective end sector 50. A request is sent to remove the sectors 40a, 40b and 50 to the control unit and control, which commands the shortening of the bi-directional drive system 2 to remove the fairing 120, 220 nacelle.

The gear-rack pairs 4a-4a, 4b-4b and 3c-4c are driven as described above.

Therefore, the sectors 40a, 40b, 50 are retracted circumferentially around the rotor 110, 210 (in the direction of arrows F2 in FIGS. 1-4 and 7 and 8), starting from the end sector 50, which enters the distal intermediate sector 40a, then the distal intermediate sector 40a extends into proximal intermediate sector 40b and finally proximal intermediate sector 40b extends into fixed sector 30.

When all the retractable sectors 40a, 40b and 50 of a row enter into each other and into the stationary sector 30 of that row, the rotor 110, 210 can be likened to an open rotor.

The claimed propulsion system 100, 200 also includes locking means in the opening position of the fairing 120, 220 of the gondola, in other words, when all the retractable sectors 40a, 40b and 50 of the row come from each other and into the fixed sector 30 of this row. These means are, for example, complementary mechanical means located on the fixed sector 30 and on the end sector 50, and these complementary means are configured to connect the end sector 50 to the fixed sector 30 and, therefore, all intermediate sectors. Another solution for blocking the sectors in the retracted position may be to block the rotation of the electric motor 5.

In this case, for the same obvious safety reasons, it is necessary to be able to ensure that the fairing 120, 220 of the nacelle is well locked in the retracted position. Therefore, the propulsion system 100, 200 may preferably be equipped with a monitoring device, such as an analog switch, configured to alert the user or computing device that the nacelle fairing 120, 220 is actively locked in a retracted position. Similarly, if the analog switch detects poor locking of the nacelle fairing 120, 220 in the retracted position, an alarm signal (eg, by means of an audible or light signal) can be transmitted to the aircraft user, for example, on the instrument panel of the aircraft cockpit.

Thus, the claimed propulsion system 100, 200 makes it possible to simply and quickly, depending on the needs of the aircraft 1, use either cowled rotors or open rotors. When the nacelle fairing 120, 220 is fully deployed around the rotors 110, 210, the rotor is fully cowled. Thus, the nacelle fairing 120, 220 of the claimed propulsion system 100, 200 can, due to its shape, its construction and the materials of which it is made, act as an acoustic shield against the noise produced by the rotation of the rotors 110, 210, guaranteeing a better attenuation of acoustic emissions, as well as provide increased safety of the rotors in relation to possible obstacles and at the same time use the thrust effect of the nacelle fairing during hover or low speed flight. When the nacelle fairing 120, 220 is retracted into fixed sectors, drag from the presence of a possible nacelle fairing is substantially eliminated, and propulsive efficiency at low speed is greatly improved, while the rotors 110, 210 are open.

Thus, an advantage of the claimed aircraft is that, depending on the needs, it can have cowled rotors or open rotors.

Claims (28)

1. Propulsion system (100, 200) for an aircraft, containing at least one rotor (110, 210) and a gondola having a fairing (120, 220) located around said at least one rotor (110, 210), moreover this nacelle fairing (120, 220) is divided into sectors and contains at least one fixed sector (30, 130a, 130b, 130ab, 230ad, 230bc) and sectors (40a, 40b, 50, 141a, 141b, 142a, 142b, 150a , 150b, 240a, 240b, 240c, 240d, 250a, 250b, 250c, 250d), retractable in the circumferential direction (F1, F2) relative to the axis of rotation (X) of the rotor (110, 210), with the retractable sectors (141a, 141b, 142a, 142b, 150a, 150b, 240a, 240b, 240c, 240d, 250a, 250b, 250c, 250d) contain at least one first row of sectors (141a, 142a, 150a; 240a, 250a; 240d, 250d ), telescopically retractable inside or on said at least one fixed sector (130a; 130ab; 230ad), and characterized in that said retractable sectors (141a, 141b, 142a, 142b, 150a, 150b, 240a, 240b, 240c, 240d, 250a, 250b , 250c, 250d) also contain at least one second row of sectors (141b, 142b, 150b; 240b, 250b; 240c, 250c) telescopically retracting inward or onto said at least one fixed sector (130b; 130ab; 230bc), while said at least one fixed sector (30, 130a, 130b, 130ab, 230ad, 230bc) has an angular size around said axis (X), less than or equal to 90°. 2. Propulsion system (100, 200) according to the previous paragraph, in which the retractable sectors (141a, 142a, 150a; 240a, 250a; 240d, 250d) of the first row of sectors are telescopically retractable one inside the other and inside said at least one fixed sector (130a; 130ab; 230ad), and retractable sectors (141b, 142b, 150b; 240b, 250b; 240c, 250c) of the second row of sectors are telescopically retractable one inside the other and inside said at least one fixed sector (130b; 130ab; 230bc ). 3. The propulsion system (100, 200) according to one of the previous paragraphs, in which the retractable sectors (40a, 40b, 50) are made with the possibility of triggering their retraction either automatically, depending on predetermined flight conditions of the aircraft (1), or according to a special user command. 4. Propulsion system (100, 200) according to the previous paragraph, in which the retractable sectors (141a, 141b, 142a, 142b, 150a, 150b, 240a, 240b, 240c, 240d, 250a, 250b, 250c, 250d) have a common tubular shape and each have transverse dimensions that decrease from one circumferential end to the opposite circumferential end. 5. Propulsion system (100, 200) according to any of the previous paragraphs, in which each of the rows of sectors contains: - end sector (50; 150a, 150b; 250a, 250b, 250c, 250d) and - at least one intermediate sector (40a, 40b; 141a, 141b, 142a, 142b; 240a, 240b, 240c, 240d); while the end sector (50; 150a, 150b; 250a, 250b, 250c, 250d) of the first row of sectors contains the means of the final direction (52) and blocking (53), made with the possibility of interacting with complementary means of the final direction (52) and blocking ( 53) with which the end sector (50; 150a, 150b; 250a, 250b, 250c, 250d) of the second row of sectors is equipped to lock the fairing (120,220) of the nacelle in the closed position. 6. Propulsion system (100, 200) according to one of the previous paragraphs, in which at least some of the sectors (30, 40a, 40b, 50) contain sealing means, for example, at the level of their circumferential ends, made with the possibility of ensuring tightness with adjacent sector or adjacent sectors. 7. Propulsion system (100, 200) according to one of the previous paragraphs, containing a device for activating the deployment or retraction of sectors (40a, 40b, 50, 141a, 141b, 142a, 142b, 150a, 150b, 240a, 240b, 240c, 240d, 250a , 250b, 250c, 250d) of each row, and this device contains a bi-directional drive system (2) with a link for telescopic deployment and removal of the said sectors, from the fixed sector, or inside the fixed sector, or onto the fixed sector (30, 130a, 130b, 130ab, 230ad, 230bc). 8. Propulsion system (100, 200) according to the previous paragraph, in which the bi-directional drive system (2) contains gears (3a, 3b, 3c) and segments (4a, 4b, 4c) of the rack driven by one electric motor (5 ), wherein the bidirectional system (2) is configured to engage the pinion (3a) with at least one toothed rack (4a) of the end sector (50), then, sequentially, engage the gears (3b, 3c) with the toothed racks of each intermediate sector (40a, 40b), from one to the other, from the fixed sector (30) in case of deploying the nacelle fairing (120, 220) or to the fixed sector (30) in case of retracting the nacelle fairing (120, 220). 9. Propulsion system (100, 200) according to the previous paragraph, in which the sectors (30, 40a, 40b, 50) contain at least one segment (6a, 6b, 6c, 6d) of the wings having a U-shaped cross section. 10. The method of controlling the fairing (110, 210) of the nacelle of the propulsion system (100, 200) for the aircraft (1) according to any one of paragraphs. 1-9, from the open, respectively closed position of said nacelle fairing (120, 220), characterized in that the retractable sectors (40a, 40b, 50, 141a, 141b, 142a, 142b, 150a, 150b, 240a, 240b, 240c, 240d, 250a, 250b, 250c, 250d) are telescopically deployed, respectively go into each other in the circumferential direction (F1, respectively F2) relative to the axis of rotation (X) of the rotor (110, 210), from, respectively, inside or on the mentioned at least one fixed sector (130a, 130b; 130ab; 230ad; 230bc). 11. The control method according to claim 10, wherein deploying the nacelle fairing (120, 220) from the nacelle fairing (120, 220) opening position comprises the following steps: - detecting a predetermined flight condition for automatic control or manual control of closing the fairing (120, 220) of the gondola; - transmit a request for the deployment of sectors (40a, 40b, 50) to the control and management unit; - command to extend the bidirectional drive system (2) to deploy the fairing (120, 220) nacelle in the circumferential direction (F1) around the rotor (110, 210) from the fixed sector or each fixed sector (30); - blocking the fairing (120, 220) of the nacelle in the deployed position by means (53) of blocking the end sector or each end sector (50); - detect active lock conditions in the deployed position and notify the user about them. 12. The control method according to the previous paragraph, in which a predetermined condition for automatic control of the closing of the fairing (120, 220) of the gondola is the phase of the hover mode of the aircraft (1) or the speed of the aircraft (1), less than or equal to 180 km/h. 13. The control method according to claim 10, wherein retracting the nacelle fairing (120, 220) from the nacelle fairing (120, 220) closing position comprises the following steps: - detecting a predetermined flight condition for automatic control or manual control of the opening of the fairing (120, 220) of the gondola; - transmit a request to remove sectors (40a, 40b, 50) to the monitoring and control unit; - a shortening command is given to the bidirectional drive system (2) to retract the fairing (120, 220) of the nacelle in the circumferential direction (F2) around the rotor (110, 210) until the sectors completely enter the fixed sector or each fixed sector (30); - block the fairing of the gondola in the retracted position; - detect active interlock conditions in the retracted position and notify the user about them. 14. The control method according to the previous paragraph, wherein the predetermined condition for automatically controlling the opening of the fairing (120, 220) of the nacelle is the speed of the aircraft (1) exceeding 180 km/h. 15. Aircraft (1), characterized in that it contains at least one propulsion system (100, 200) according to any one of paragraphs. 1-9, while the propulsion system (100, 200) is installed with the possibility of rotation on the aircraft (1) using a rotary shaft (10, 20), which is remote or through relative to the rotor (110, 210).

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