Propulsion unit for an aircraft

Abstract

The invention relates to a propulsion unit (10) for an aircraft, said propulsion unit (10) comprising:-an engine pylon (12),-a turbine engine (14) fixed to the engine pylon (12) and comprising a fluid system (18),-a fairing (16), the fairing comprises at least one panel (20) pivotally connected to the engine hanger (14) and carrying at least one surface heat exchanger (26), the at least one surface heat exchanger comprises a fluid circuit (26 ') connected to the fluid system (18), where the fluid circuit (26') is connected to the fluid system (18) by at least one rotary joint (30, 30 ') centered on the axis of rotation of the corresponding panel (20).

Description

Technical field

[0001] The present invention relates to a propulsion unit for an aircraft. Background art

[0002] The prior art includes documents FR-A1-3 094 750, US-A1-2020 / 049028, US-A1-2021 / 078380, FR-A1-2 567 081 and CN-U,207 854 371.

[0003] Figure 1 A propulsion unit 10 for an aircraft is shown.

[0004] In the present application, the "propulsion unit 10" for an aircraft refers to a component including an engine pylon 12, a turbomachine 14 and its nacelle 16.

[0005] The engine pylon 12 is a solid part for attaching the turbomachine 14 to an aircraft (for example, an aircraft wing). Thus, the engine pylon 12 includes elements for attaching to the aircraft and elements for attaching the turbomachine 14. The engine pylon 12 has a generally elongated shape and extends along a first axis A.

[0006] In the present application, the turbomachine 14 is located below or near the engine pylon 12. The turbomachine can be suspended on the engine pylon 12 and located below the aircraft wing. Alternatively, the turbomachine can be installed at the rear of the aircraft fuselage.

[0007] The turbomachine 14 has a generally elongated shape along a second axis B, and the second axis B can be parallel to the first axis A. The first axis A and the second axis B are located in the same plane P. The plane P can be vertical or inclined with respect to the vertical direction.

[0008] Similar to a watch face when viewed from the rear, the 12 o'clock position and the 6 o'clock position are positions of the components around the second axis B. The 12 o'clock position is located in the plane P and at the engine pylon 12, and the 6 o'clock position is located in the plane P and below the turbomachine 14.

[0009] The turbomachine 14 includes a lubrication system 18, and the lubrication system 18 lubricates the bearings of the turbomachine in particular by circulating lubricating oil.

[0010] The fairing 16 surrounds the turbomachine 14 and extends along a second axis B. The fairing 16 may include a plurality of parts and includes two panels 20 of generally semi-circular shape, the two panels 20 extending on either side of the plane P. These panels 20 include an upper longitudinal edge 22 and a lower longitudinal edge 24, the upper longitudinal edge 22 being fixed to the engine pylon 12 and arranged on either side of the plane P and near the 12 o'clock position, and the lower longitudinal edge 24 being generally fixed to each other and thus located at the 6 o'clock position.

[0011] These panels 20 rotate about their upper edges 22 such that the fairing 16 can be opened to allow access to the turbomachine 14, for example during ground maintenance operations. This connection can be achieved by hinges 25 for fixing the upper edges 22 of the panels 20 to the engine pylon 12. Each of the panels 20 rotates, for example, from a closed position to an open position about a third axis C, in the closed position, the lower edge 24 of the panel being located at the 6 o'clock position, and in the open position, the lower edge 24 of the panel being away from the 6 o'clock position, the third axis C being parallel to the second axis B.

[0012] The fairing 16 may carry at least one surface heat exchanger 26. This type of exchanger 26 includes an oil circuit 26' and an exchange surface, the oil circuit 26' being connected to the lubrication system 18, and the exchange surface being exposed to a cooling air flow. The heat exchange between the surface of the exchanger and the oil circuit 26' makes it possible to cool the oil from the lubrication system 18 before returning it to the lubrication system 18, as Figure 1 shown by the dashed arrow in.

[0013] At least a part of the fairing 16 may delimit internally an annular duct for the air flow around the turbomachine 14, such as a flow duct for a secondary flow, etc. In this case, the exchange surface of the heat exchanger 26 is swept by this air flow.

[0014] The heat exchanger 26 carried by the fairing 16 is connected to the lubrication system 18 by fluid connection means which must allow the panel 20 to be opened (in particular to be pivoted) without requiring the heat exchanger 26 to be disconnected from the lubrication system 18.

[0015] In the current state of the art, these connection means are flexible hoses 28, as Figure 2 shown. Each of these hoses 28 includes an end 28a and an opposite end 28b, the end 28a being fixed to the panel 20 and intended to be connected to the heat exchanger 26 carried by this panel 20, and the opposite end 28b being fixed to the engine pylon 12 and intended to be connected to the lubrication system 18 of the turbomachine 14. Whatever the position of the panel 20, due to the flexibility of the hoses 28, the oil circuit 26' of the exchanger 26 remains connected to the lubrication system 18. Figure 2Shows two different deformed states of the same hose 28 for two different positions of the panel 20.

[0016] This technique has its drawbacks. First, the environment around the hose 28 must be kept unused so as not to impede the movement of the hose 28 when the panel 20 is opened and closed. The hose 28 is also relatively long so that the hose can bend without causing stresses that would lead to breakage or permanent deformation. Thus, this technique is relatively bulky. In addition, these hoses 28 are oversized to have sufficient resistance and, in particular, have a large diameter due to the presence of a thick protective layer around these hoses 28 to resist fire and other assaults. Finally, this technique is relatively expensive and of high quality.

[0017] Climate change is also a major concern for many legislative and regulatory bodies around the world. States have adopted, are adopting, or will adopt various restrictions on carbon emissions. In particular, advanced standards apply both to new aircraft and to those already in circulation that need to implement technical solutions to comply with current regulations. For many years, civil aviation has been working to help combat climate change. Technical research work has significantly improved the environmental performance of aircraft. The applicant has taken into account the influencing factors at all stages of design and development in order to obtain aviation components and products that consume less energy, are more environmentally friendly, and whose integration and use in civil aviation have a moderate impact on the environment, with the aim of improving the energy efficiency of aircraft. Thus, the applicant is constantly striving to reduce the negative impact of civil aviation on the climate by adopting methods and using beneficial development and manufacturing methods, and to reduce greenhouse gas emissions to the lowest possible level in order to reduce the environmental footprint of civil aviation business. This ongoing research and development work focuses on a new generation of aircraft engines, which makes the aircraft lighter (especially through the materials used and lighter on-board equipment), the development of propulsion using electric technology, and the development of aviation biofuels as an important complement to technological progress.

[0018] The present invention provides a simple, effective, and economical solution to at least some of the above problems of the prior art. Summary of the Invention

[0019] The present invention is the result of a technical research aimed at significantly improving the performance of an aircraft and, in this sense, contributes to reducing the impact of the aircraft on the environment.

[0020] The present invention relates to a propulsion unit for an aircraft, the propulsion unit comprising:

[0021] - An engine pylon that extends along a first axis,

[0022] - A turbomachine fixed to the engine pylon that extends along a second axis, the first axis and the second axis extending in the same plane, the turbomachine comprising a fluid system,

[0023] - A fairing that extends along and around a second axis. The fairing includes at least one panel that has a generally semi-circular shape and extends around the second axis. The at least one panel includes a longitudinal edge that is fixed to the engine pylon by a hinge that defines a third pivot axis about which the panel pivots from a closed position to an open position. In the closed position, the panel extends around the turbomachine. In the open position, the panel moves away from the turbomachine. The at least one panel carries at least one surface heat exchanger, and the at least one surface heat exchanger includes a fluid circuit connected to the fluid system.

[0024] It is characterized in that the fluid circuit is connected to the fluid system by at least one rotary joint. The at least one rotary joint is centered on the third axis. The at least one rotary joint is connected to the fluid circuit by a first rigid conduit and to the fluid system by a second rigid conduit. The rotary joint includes a first member rigidly fixed to the first conduit and a second member rigidly fixed to the second conduit. The first member and the second member are assembled to be able to rotate relative to each other about the third axis, and the first member and the second member are assembled to ensure fluid communication between the first conduit and the second conduit regardless of the positions of the first member and the second member about the third axis.

[0025] Thus, the present invention proposes to connect the fluid circuit of the panel exchanger to the fluid system of the turbomachine by at least one rotary joint. A first specific characteristic of this rotary joint is that the rotary joint is centered on the third axis, that is, on the joint axis of the corresponding panel. Thus, there is no particular stress on the joint because the joint follows the movement of the panel when the panel moves. Different from the hoses of the prior art, another specific characteristic of the rotary joint is that the rotary joint is composed of rigid elements. The rotary joint includes rigid conduits and members for connecting and articulating these rigid conduits. The fluid connection between the fluid circuit and the fluid system is continuously ensured regardless of the position of the panel.

[0026] The propulsion unit according to the present invention may include one or more of the following features taken alone or in combination with each other:

[0027] - Each of the first member and the second member includes an L-shaped internal channel. A first end of the L-shaped internal channel is connected to the corresponding conduit, and a second end of the L-shaped internal channel is connected to the other member.

[0028] - One of the first member and the second member includes a convex end member that engages along the third axis in a concave end member of the other of the first member and the second member.

[0029] - At least one washer or sealing device is installed between the convex end member and the concave end member;

[0030] - The fluid circuit is connected to the fluid system through two rotary joints centered on the third axis. The first rotary joint among these rotary joints is connected to the inlet of the fluid circuit, and the second rotary joint among these rotary joints is connected to the fluid outlet of the circuit;

[0031] - The first rotary joint and the second rotary joint are spaced apart from each other by a distance;

[0032] - The first rotary joint and the first rotary joint are arranged side by side;

[0033] - At least one valve is installed between the fluid system and the second rigid conduit of the rotary joint or each rotary joint;

[0034] - The at least one panel includes a concave surface, and the at least one heat exchanger is located on the concave surface;

[0035] - The plane is vertical or inclined with respect to the vertical direction, and the first axis and the second axis extend in the plane;

[0036] - The fluid circuit is an oil circuit or a coolant circuit;

[0037] - The fluid circuit is connected to the fluid system through at least one double rotary joint. The at least one double rotary joint includes:

[0038] - A first rigid conduit that extends between the fluid circuit and the first member of the first joint,

[0039] - A second rigid conduit that extends between the second member and the third member of the first joint. The third member is rigidly fixed to one end of the second conduit,

[0040] - A third rigid conduit that extends between the fluid system and the fourth member. The fourth member is rigidly fixed to one end of the third conduit,

[0041] The third member and the fourth member form the second rotary joint. The third member and the fourth member are assembled to be able to rotate relative to each other about a fourth axis parallel to the third axis. The third member and the fourth member are assembled to ensure fluid communication between the second conduit and the third conduit regardless of the positions of the third member and the fourth member about the fourth axis,

[0042] - A fairing surrounds at least a part of the turbomachine,

[0043] - The fairing includes two panels of a generally semi-circular shape that extend on both sides of the main axis,

[0044] - Each of these panels includes an upper longitudinal edge and a lower longitudinal edge,

[0045] - The upper longitudinal edge of the panel or each panel is fixed by a hinge;

[0046] - Another panel among the panels carries another heat exchanger or another type of fluid device,

[0047] -- The turbomachine extends below or near the engine pylon,

[0048] -- The panel or each panel has a substantially semi-circular shape. Description of the Drawings

[0049] Other features and advantages will appear from the following description of non-limiting embodiments of the invention and with reference to the drawings, in which:

[0050] Figure 1 Figure 1 is a partial schematic perspective view of a propulsion unit for an aircraft,

[0051] Figure 2 Figure 2 is a schematic perspective view of a fluid connection device for fluidly connecting a heat exchanger to a fluid system according to the prior art of the invention,

[0052] Figure 3 Figure 3 is a schematic perspective view of the technology for a fluid connection device in the context of the invention,

[0053] Figure 4 Figure 4 is a schematic axial cross-sectional view of a fluid connection device in the context of the invention,

[0054] Figure 5 Figure 5 is a schematic axial cross-sectional half view of a propulsion unit for an aircraft and shows a first embodiment of the invention,

[0055] Figure 6 Figure 6 is a schematic axial cross-sectional half view of a propulsion unit for an aircraft and shows a second embodiment of the invention, and

[0056] Figure 7 Figure 7 is a schematic axial cross-sectional half view of a propulsion unit for an aircraft and shows a third embodiment of the invention. Detailed Description

[0057] The foregoing has been described​​​​​​​​​​​​​​Figure 1 and Figure 2 。

[0058] Figure 1 can be considered as showing a propulsion unit 10 within the meaning of the present invention, and thus the foregoing description related thereto Figure 1 can also be considered as related to the present invention.

[0059] For example, the propulsion unit 10 can be located below the wing of the aircraft or at the rear of the aircraft fuselage.

[0060] Furthermore, the propulsion unit 10 can be of any type, for example, a two-stream or three-stream turbojet engine, a turbofan engine with a ducted or unducted fan, a turboprop engine, an open rotor engine, etc.

[0061] Figure 2 shows a connection device of the prior art, which is located between a fluid or fluid circuit 26' of a heat exchanger 26 carried by a fairing panel 20 and a lubrication system 18 of a turbofan engine 14. These connection devices include flexible hoses 28 and have the above-mentioned disadvantages.

[0062] The present invention proposes different techniques for connecting the fluid circuit 26' of the exchanger 26 to the fluid system 18 of the turbofan engine 14.

[0063] For example, the fluid system 18 is a lubrication system, but alternatively can be a cooling system. For example, the fluid circuit 26' is an oil circuit, but alternatively can be a coolant circuit.

[0064] The principle of this technique is shown in Figure 3 and involves the use of one or more rotary joints 30. Figure 3 shows three rotary joints 30a, 30b, 30c connected to each other by rigid ducts.

[0065] The first rigid duct 32 extends between a valve 33 or faucet and the first joint 30a. The second rigid duct 34 extends between the first joint 30a and the second joint 30b. The third rigid duct 36 extends between the second joint 30b and the third joint 30c. Finally, the fourth rigid duct 38 extends between the third joint 30c and the fluid outlet 40.

[0066] Each of the joints 30a, 30b, 30c includes two members that are rigidly fixed to the corresponding ducts and are coupled to each other to ensure fluid connection between the ducts on the one hand and to enable the ducts to rotate relative to each other about an axis D on the other hand.

[0067] Thus, the member 42 attached to the end of the first conduit 32 is connected to the member 44 attached to the end of the second conduit 34. The members 42, 44 form a first rotary joint 30a about a first axis D1, and the members 42, 44 enable fluid communication between the conduits 32, 34 regardless of the positions of the members 42, 44 and the conduits 32, 34 relative to the axis D1.

[0068] The member 46 attached to the other end of the second conduit 34 is connected to the member 48 attached to the end of the third conduit 36. The members 46, 48 form a second rotary joint 30b about a second axis D2, and the members 46, 48 enable fluid communication between the conduits 34, 36 regardless of the positions of the members 46, 48 and the conduits 34, 36 relative to the axis D2.

[0069] The member 50 attached to the other end of the third conduit 36 is connected to the member 52 attached to the end of the fourth conduit 38. The members 50, 52 form a third rotary joint 30c about a second axis D3, and the members 50, 52 enable fluid communication between the conduits 36, 38 regardless of the positions of the members 50, 52 and the conduits 36, 38 relative to the axis D3.

[0070] The axes D1, D2, and D3 are parallel.

[0071] Figure 4 A cross-section of the rotary joint 30a is shown, and the other rotary joints 30b, 30c are similar.

[0072] The conduit 32 includes an internal passage 32a for fluid flow, which extends along its entire length and is connected to one end of the internal passage 42a of the member 42. The internal passage 42a of the member 42 is generally L-shaped, and the end of the internal passage 42a opposite to the conduit 32 is connected to one end of the L-shaped internal passage 44a of another member 44. The conduit 34 includes an internal passage 34a, which extends along its entire length and is connected to the opposite end of the internal passage 42a of the member 42.

[0073] The L-shaped passage includes two perpendicular portions, namely a first portion extending in one direction and a second portion extending in a direction perpendicular to the first portion, and the two portions are in fluid communication.

[0074] For example, as shown, the components 42, 44 can be assembled by means of a male-female interlocking connector. The interlocking takes place along the axis D1 and enables the joint 30a to be formed around this axis. In the example shown, the component 42 includes a female end part 42b through which a channel 42a passes, and the female end part 42b receives the male end part 44b of the component 44, which also passes through a channel 44a in this component 44.

[0075] A sealing device such as one or more annular seals 54 can be fitted to the end parts 42b, 44b.

[0076] Figure 5 A first embodiment of a propulsion unit 10 according to the present invention is shown. As described above, the propulsion unit 10 includes:

[0077] - an engine pylon 12,

[0078] - a turbomachine 14, the turbomachine 14 including a fluid system 18, and

[0079] - a nacelle 16, in the example shown, the nacelle 16 can surround the turbomachine 14.

[0080] In the example shown, the nacelle 16 includes two panels 20 of generally semi-circular shape, which extend on either side of the aforementioned plane P and include upper longitudinal edges 22 fixed to the engine pylon 12 by hinges 25. These upper edges 22 are substantially at the 12 o'clock position and are separated from each other by the engine pylon 12.

[0081] In the example shown, there are three hinges 25 arranged one after the other along the axis C. Thus, there is an upstream hinge, a middle hinge and a downstream hinge. Preferably, two of these hinges are fixedly mounted and the third hinge is floatingly mounted to ensure perfect alignment.

[0082] Each of the panels 20 is pivotally connected, for example, from a closed position to an open position about a third axis C (defined by the hinge 25). In the closed position, the lower edge (not visible) of the panel is substantially at the 6 o'clock position, and in the open position, the lower edge of the panel is away from the 6 o'clock position. The third axis C can be parallel to the second axis B. For example, the angular deflection between the two positions is greater than 30° about the axis C.

[0083] Each of the panels 20 carries at least one surface heat exchanger 26, the at least one surface heat exchanger 26 including a fluid circuit 26' and an exchange surface, the fluid circuit 26' being connected to the fluid system 18 and the exchange surface being exposed to the cooling gas flow 4.

[0084] In the example shown, the exchanger 26 is located on the concave curved surface of the panel 20, which is oriented towards the axis B and is thus the inner surface of the panel. This location is not exhaustive. Alternatively, for example, the heat exchanger 26 could be located on the outer convex surface of the panel 20.

[0085] In the context of the present invention, the panel 20 can be an inner panel or an outer panel of a turbomachine and a propulsion assembly, and the panel 20 can be traversed by a gas flow (in particular a secondary flow or a flow external to the turbomachine) on the inner or outer side of the panel. Thus, the heat exchanger 26 is located on the inner or outer side of the panel 20 and is thus on the inner or outer surface of this panel 20.

[0086] The fluid connection means for fluidly connecting the fluid circuit 26’ of each exchanger 26 to the fluid system 18 includes at least one rotary joint 30 as described above.

[0087] In the example shown, the fluid circuit 26’ includes a fluid inlet 26a and a fluid outlet 26b. The fluid system 18 includes a fluid inlet 18a and a fluid outlet 18b.

[0088] The fluid inlet 26a of the circuit 26’ is connected to the fluid outlet 18b of the system 18 by a first joint 30, the first joint 30 being centered on the pivot axis C of the panel 20, the panel 20 carrying the exchanger 26 having this circuit 26’. This first joint 30 is connected to the inlet 26a and the outlet 18b respectively by rigid conduits 32, 34, or to pipes connected to this inlet and outlet. In the example shown, the first joint is adjacent to one of the hinges 25, which is the intermediate hinge 25a in the example shown. Advantageously, a valve 33 is inserted between the joint 30 and the outlet 18b, i.e., just upstream of the joint 30. This valve 33 is also capable of being centered on the axis C. The figure shows the hinge 25a located between the valve 33 and the joint 30.

[0089] The fluid outlet 26b of the circuit 26’ is connected to the fluid inlet 18a of the system 18 by a second joint 30’, the second joint 30’ being centered on the pivot axis C of the panel 20, the panel 20 carrying the exchanger 26 having this circuit 26’. This second joint 30’ is connected to the outlet 26b and the inlet 18a respectively by rigid conduits 32, 34, or to pipes connected to this outlet and inlet. In the example shown, the second joint is adjacent to the other of the hinges 25, which is the downstream hinge in the example shown. Advantageously, a valve 33 is inserted between the joint 30’ and the inlet 18a, i.e., just downstream of the joint 30’. This valve 33 is also capable of being centered on the axis C. The figure shows the hinge 25b located between the valve 33 and the joint 30’.

[0090] Thus, the joints 30, 30' are spaced apart from each other along the axis C by a distance.

[0091] For example, one or more valves 33 can be used to isolate the fluid circuit so that the heat exchanger 26 or the panel 20 can be removed for maintenance.

[0092] Figure 6 The alternative design shown differs from the foregoing embodiment in that the two joints 30, 30' are positioned adjacent to each other rather than being spaced apart from each other by a distance.

[0093] As shown, the member 42 of the first joint 30 is inserted between the member 44 of the joint 30 and the member 42' of the second joint 30'.

[0094] The joints 30, 30' are located at the first hinge 25a, on one side of the hinge 25a. The valve 33 associated with the first joint 30 is located on the other side of the hinge 25a, and the joint is located between the hinge 25a and the other valve 33.

[0095] Figure 7 The embodiment shown differs from the foregoing embodiment in that Figure 7 the embodiment shown does not use a single rotary joint for each fluid connection, but instead uses a double rotary joint, which enables the double rotary joint to be aligned with the same axis of rotation as the hinge 25.

[0096] The fluid inlet 26a of the circuit 26' is connected to the fluid outlet 18b of the system 18 through a double joint. For example, the double joint includes Figure 3 joints 30a and 30b of the type shown. The first joint 30a is centered on the axis C, and the second joint 30b is centered on an axis parallel to the axis C.

[0097] The present invention has many advantages, including:

[0098] - The conduit is rigid, which is advantageous in terms of cost, weight, and maintenance.

[0099] - The diameter of the conduit is optimized and does not need to be excessive, which makes it easier to integrate the rotary joint into the environment.

[0100] - Except in the last variant and in the case of using a double rotary joint, there is no relative movement of the joints.

[0101] - The length of the rotary joint is also optimized.

[0102] - Maintenance is simplified and costs are lower because the disassembly of the fluid circuit is simpler and faster.

[0103] - The last variant allows misalignment with respect to the axis C of the hinge.

Claims

1. A propulsion unit (10) for an aircraft, the propulsion unit (10) comprising: - an engine pylon (12) extending along a first axis (A), - a turbomachine (14) fixed to the engine pylon (12), the turbomachine (14) extending along a second axis (B), the first axis and the second axis (A, B) extending in the same plane (P), the turbomachine (14) comprising a fluid system (18), - a nacelle (16) extending along the second axis (B) and around the second axis, the nacelle (16) comprising at least one panel (20) extending around the second axis, the at least one panel (20) comprising a longitudinal edge (22), the longitudinal edge being fixed to the engine pylon (14) by a hinge (25), the hinge defining a third pivot axis (C) about which the panel pivots from a closed position to an open position, in the closed position, the panel extends around the turbomachine (14), in the open position, the panel moves away from the turbomachine (14), the at least one panel (20) carrying at least one surface heat exchanger (26), the at least one surface heat exchanger comprising a fluid circuit (26') connected to the fluid system (18), characterized in that the fluid circuit (26') is connected to the fluid system (18) by at least one rotary joint (30, 30'), the at least one rotary joint being centered on the third axis (C), the at least one rotary joint being connected to the fluid circuit (26') by a first rigid conduit (32) and to the fluid system (18) by a second rigid conduit (34), the rotary joint (30, 30') comprising a first member (42) rigidly fixed to the first conduit (32) and a second member (44) rigidly fixed to the second conduit (34), the first member and the second member (42, 44) being assembled so as to be able to rotate relative to each other about the third axis (C), the first member and the second member being assembled so as to ensure fluid communication between the first conduit and the second conduit (32, 34) regardless of the position of the first member and the second member (42, 44) about the third axis (C).

2. The propulsion unit (10) according to claim 1, wherein, Each of the first member and the second member (42, 44) comprises an L-shaped internal channel (42a, 44a), a first end of the L-shaped internal channel being connected to the corresponding conduit (32, 34), and a second end of the L-shaped internal channel being connected to the other member (44, 42).

3. The propulsion unit (10) according to claim 1 or 2, wherein, One of the first member and the second member (42, 44) comprises a convex end part (44b) that engages, along the third axis (C), in a concave end part (42b) of the other of the first member and the second member (44, 42).

4. The propulsion unit (10) according to claim 3, wherein, At least one washer or sealing device (54) is installed between the convex end member and the concave end members (42b, 44b).

5. The propulsion unit (10) according to any one of the preceding claims, wherein, The fluid circuit (26’) is connected to the fluid system (18) by two rotary joints (30, 30’) centered on the third axis (C). The first rotary joint (30) of these rotary joints is connected to the inlet (26a) of the fluid circuit (26’), and the second rotary joint (30’) of these rotary joints is connected to the fluid outlet (26b) of the circuit (26’).

6. The propulsion unit (10) according to claim 5, wherein, The first rotary joint and the second rotary joint (30, 30’) are spaced apart from each other by a distance.

7. The propulsion unit (10) according to claim 5, wherein, The first rotary joint and the second rotary joint (30, 30’) are arranged side by side.

8. The propulsion unit (10) according to any one of the preceding claims, wherein, At least one valve (33) is installed between the fluid system (18) and the second rigid conduit (34) of the rotary joint or each rotary joint (30, 30’).

9. The propulsion unit (10) according to any one of the preceding claims, wherein, The fluid circuit (26’) is connected to the fluid system (18) by at least one double rotary joint (30a, 30b), and the at least one double rotary joint includes: - The first rigid conduit (32), which extends between the fluid circuit (26’) and the first member (42) of the first joint (30a), - The second rigid conduit (34), which extends between the second member (44) and the third member (46) of the first joint (30a). The third member is rigidly fixed to one end of the second conduit (34), and - The third rigid conduit (36), which extends between the fluid system (18) and the fourth member (48). The fourth member is rigidly attached to one end of the third conduit (36), The third member and the fourth member (46, 48) form the second rotary joint (30b). The third member and the fourth member are assembled to be able to rotate relative to each other about a fourth axis parallel to the third axis (C). The third member and the fourth member are assembled to ensure fluid communication between the second conduit and the third conduit (34, 36) regardless of the positions of the third member and the fourth member (46, 48) around the fourth axis.

10. The propulsion unit (10) according to claim 5, wherein, The at least one panel (20) includes a concave surface, and the at least one heat exchanger (26) is located on the concave surface.

11. The propulsion unit (10) according to any one of the preceding claims, wherein, The plane (P) is vertical or inclined relative to the vertical direction, and the first axis and the second axis extend in the plane.

12. The propulsion unit (10) according to any one of the preceding claims, wherein, The fluid circuit (26’) is an oil circuit or a coolant circuit.

13. The propulsion unit (10) according to any one of the preceding claims, wherein, The fairing (16) includes two panels (20) with a generally semi-circular shape, which extend on both sides of the main axis. Each of these panels has an upper longitudinal edge (22) and a lower longitudinal edge (24), and the upper longitudinal edge of the panel or each panel is fixed by the hinge (25).

14. The propulsion unit (10) according to the previous claim, wherein, The other panel of the panels (20) carries another heat exchanger or another type of fluid device.

15. The propulsion unit (10) according to any one of the preceding claims, wherein, The panel or each panel (20) has a substantially semi-circular shape.

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