Aircraft nacelle cowling

Abstract

A nacelle cowling (6a, 7) for an aircraft incorporating a propulsion unit is proposed. The nacelle cowling comprises an inner skin (11a, 11b) made of composite materials and configured to cover at least part of a turbomachine of the propulsion unit, and an outer skin (12a, 12b) made of composite materials and opposed to the inner skin. At least one first main housing (17, 22) is formed between the inner and outer skins, the first main housing opening onto a first side (13a, 13c) of the cowling and housing a first main connecting means configured to fix the cowling to an element of the propulsion unit. Figure for the abstract: Fig 6

Description

Title of the invention: Aircraft nacelle cowling technical field

[0001] The invention relates generally to bodywork elements for an aircraft.

[0002] It relates more particularly to nacelle hoods for aircraft. Previous techniques

[0003] Climate change is a major concern for many legislative and regulatory bodies worldwide. Indeed, various restrictions on carbon emissions have been, are being, or will be adopted by various states. In particular, an ambitious standard applies to both new types of aircraft and those already in service, requiring the implementation of technological solutions to bring them into compliance with current regulations. Civil aviation has been actively working for several years now to contribute to the fight against climate change.

[0004] Technological research efforts have already led to very significant improvements in the environmental performance of aircraft. The Applicant takes into account the factors impacting all phases of design and development in order to obtain less energy-intensive and more environmentally friendly aeronautical components and products, whose integration and use in civil aviation have moderate environmental consequences, with the aim of improving the energy efficiency of aircraft.

[0005] Consequently, the Applicant is constantly working to reduce its negative climate impact by using methods and operating virtuous development and manufacturing processes that minimize greenhouse gas emissions to the minimum possible in order to reduce the environmental footprint of its activity.

[0006] This sustained research and development work focuses on new generations of aircraft engines, the weight reduction of aircraft, in particular through the materials used and lighter on-board equipment, the development of the use of electrical technologies to provide propulsion, and, as essential complements to technological progress, aviation biofuels.

[0007] An aircraft generally includes at least one turbomachine to provide its propulsion.

[0008] The turbomachine and auxiliary systems are generally housed in a nacelle held by a pylon or mast to structural elements of the aircraft.

[0009] The nacelle includes a casing formed by one or more hoods.

[0010] Fittings are arranged on the hoods and the nacelle to hold the hoods on the nacelle and to hold the hoods together in the closed position.

[0011] The fittings generally include latches and hinges so that the hoods can be moved to provide access to the turbomachine and auxiliary systems.

[0012] The fittings are generally arranged on the inside side of the hoods facing the turbomachine and are made of titanium or steel to withstand flames generated by the turbomachine during a critical failure.

[0013] The fittings are further covered with thermal protections, each comprising a thermal insulator covered with a sheet, for example, of titanium.

[0014] The thermal shields overlap between the cowlings to provide thermal protection for the fittings. However, the fittings and thermal shields are bulky, requiring space between the fittings and thermal shields and the turbomachine environment.

[0015] In addition, thermal protections and fittings made of steel or titanium increase the mass of the aircraft. Description of the invention

[0016] The aim of the invention is to overcome all or part of these disadvantages, in particular by proposing nacelle hoods with a reduced mass while being flame resistant.

[0017] To this end, the invention is the result of technological research aimed at significantly improving aircraft performance and, in this sense, contributes to reducing the environmental impact of aircraft.

[0018] For this purpose, the invention relates to a nacelle cowl for an aircraft comprising a propulsion unit, the cowl comprising an inner skin made of composite materials and configured to cover at least part of a turbomachine of the propulsion unit, and an outer skin made of composite materials and opposed to the inner skin.

[0019] At least one first main housing is formed between the inner skin and the outer skin, the first main housing opening onto a first side of the hood and housing a first main connecting means configured to fix the hood to an element of the propulsion assembly.

[0020] The inner skin of the nacelle hood made of composite materials protects the first main connecting means or fitting from a fire starting in a turbomachine housed in the nacelle or near the turbomachine.

[0021] Since the main connecting means is protected from fire, it can be made of aluminium so that the mass of the fitting is reduced.

[0022] Preferably, the nacelle hood has at least one second main housing formed between the inner skin and the outer skin, the second main housing opening onto a second side of the hood opposite the first side and housing a second main connecting means configured to fix the hood to another hood of the nacelle.

[0023] Advantageously, the second main linking means includes a receptacle configured to cooperate with a hook.

[0024] Preferably, the second main linking means includes a hook configured to cooperate with a receptacle.

[0025] Advantageously, a first wall of each main housing is formed by the inner skin and a second wall of each main housing is formed by the outer skin.

[0026] Preferably, a seal or seal compressor is disposed on the inner skin and on each side of the hood.

[0027] Advantageously, the first main connecting means includes a joint configured to form a pivot connection between the hood and the element of the propulsion assembly.

[0028] Advantageously, the nacelle hood further comprises at least one inspection window, an inspection hatch, and a first secondary housing formed between the inner and outer skin and a second secondary housing formed between the inner and outer skin, the first secondary housing opening onto a first side of the inspection window and the second secondary housing opening onto a second side of the inspection window, the second side being opposite the first side, the first secondary housing housing an auxiliary linking means configured to fix the inspection hatch on the hood and the second secondary housing housing a joint configured to form a pivot link between the inspection hatch and the hood so that the inspection hatch closes the inspection window.

[0029] Preferably, each connecting means includes a fastening means fixed to the external skin to hold said connecting means in its housing.

[0030] Advantageously, the fastening means is fixed only on the external skin. Brief description of the drawings

[0031] Other objects, features and advantages of the invention will become apparent from the following description, given solely by way of non-limiting example and made with reference to the accompanying drawings in which:

[0032] - Figure [Fig. 1] schematically illustrates an example of an aircraft according to a example of the invention,

[0033] - Figure [Fig.2] schematically illustrates an example of the realization of an assembly propulsive according to the invention,

[0034] - Figures [Fig.3], [Fig.4] and [Fig.5] schematically illustrate an example of manufacturing of nacelle hoods according to the invention,

[0035] - Figures [Fig.6] and [Fig.7] schematically illustrate a partial view of a first example of the realization of a first main connecting means according to the invention,

[0036] - Figures [Fig.8] and [Fig.9] schematically illustrate a partial view of a second example of an embodiment of the first main connecting means according to the invention,

[0037] - Figures [Fig. 10] and [Fig. 11] schematically illustrate a partial view of a example of an embodiment of a second main connecting means according to the invention, and

[0038] - Figures [Fig. 12] and [Fig. 13] schematically illustrate an example of an embodiment of an inspection window according to the invention. Detailed description

[0039] Reference is made to [Fig.1] which schematically illustrates an example of an embodiment of an aircraft 1, such as represented as an airplane, comprising two propulsion units 2 arranged on either side of the fuselage of the airplane.

[0040] Each propulsion unit 2 is fixed under a wing 3 of the aircraft 1.

[0041] According to another embodiment of aircraft 1, the propulsion units 2 are fixed to the fuselage and on either side of the fuselage.

[0042] Figure 2 schematically illustrates an example of an embodiment of the assembly propulsive 2.

[0043] The propulsion assembly 2 comprises a nacelle 4, a turbomachine 5 housed in the nacelle 4 and a mast 6 having means for fixing the propulsion assembly 2 under the wing 3.

[0044] The nacelle 4 further comprises movable hoods 7, 8, 9, 10 and a fixed hood 6a connected to the mast 6.

[0045] The hoods 7, 8, 9, 10 are held on an element of the propulsion assembly 2, such as the mast 6 or the fixed hood 6a connected to the mast 6, by first main connecting means (not shown in this figure).

[0046] The fixed hood 6a is for example fixed on a first hood of the mast 6.

[0047] A first movable cover 7 and a second movable cover 8 are held on the fixed hood 6a by the first main connecting means, and a third movable hood 9 and a fourth movable hood 10 are held on the mast 6 by the first main connecting means.

[0048] The first hood 7 and the second hood 8 are held together by second main connecting means, and the third hood 9 and the fourth hood 10 are held together by second main connecting means (not shown in this figure). As the structure of the movable hoods 7, 8, 9, 10 is identical, only the first and second hoods 7, 8 are detailed below.

[0049] Figures 3, 4 and 5 illustrate an example of an embodiment of the first and second movable hoods 7, 8 connected to the fixed hood 6a.

[0050] Reference is made more particularly to [Fig. 3], which schematically illustrates an exploded view of the example embodiment of the first and second movable hoods 7, 8 connected to the fixed hood 6a. The first and second movable hoods 7, 8 are hinged relative to the fixed hood 6a.

[0051] The fixed hoods 6a and movable hoods 7, 8 each comprise an inner skin 1 la, 11b, 1 le covering a part of the turbomachine 5 and an outer skin 12a, 12b, 12c opposite the inner skin 1 la, 11b, 1 le.

[0052] The outer skin 12a, 12b, 12c is located outside the aircraft 1.

[0053] The inner skins 11a, 11b, 11c and the outer skins 12a, 12b, 12c are not made of metallic material; they are, for example, made of composite materials, such as carbon fibers. For each fixed hood 6a and movable hood 7, 8, the inner skin 11a, 11b, 11e and the outer skin 12a, 12b, 12c are preferably formed from a single piece ensuring material continuity to allow for fireproofing in the event of a fire, for example, in the turbomachine 5 when the hoods are in the closed position (the first and second movable hoods 7, 8 are connected to each other).

[0054] The fixed hood 6a comprises a first side 13a and a second side 13b opposite the first side 13a.

[0055] Each movable cover 7, 8 comprises a first side 13c, 13d and a second side 14a, 14b.

[0056] The first side 13a of the fixed hood 6a is connected to the first side 13c of the first movable hood 7 by the first main connecting means 151.

[0057] The second side 13b of the fixed hood 6a is connected to the first side 13d of the second movable hood 8 by the first main connecting means 152.

[0058] The first main connecting means 151 linking the first side 13a of the fixed hood 6a to the first side 13c of the first movable hood 7 each comprise a first fitting 15a connected to the first movable hood 7 and a second fitting 15b connected to the fixed hood 6a.

[0059] The first main connecting means 152 linking the second side 13b of the fixed hood 6a to the first side 13d of the second movable hood 8 each comprise a first fitting 15c connected to the second movable cover 8 and a second fitting 15d connected to the fixed cover 6a.

[0060] The first and second fittings of each first main connecting means 151, 152 form an articulation between the movable hood 7, 8 and the fixed hood 6a.

[0061] The second side 14a, 14b of the first and second movable hoods 7, 8 are connected to each other by second main connecting means 16 comprising a first fitting 16a disposed on the first movable hood 7 and a second fitting 16b disposed on the second movable hood 8.

[0062] Figures 4 and 5 respectively illustrate a schematic view of the example embodiment of the first and second movable hoods 7, 8 connected to the fixed hood 6a in open and closed positions (when the first and second movable hoods 7, 8 are not connected to each other by the second main connecting means 16).

[0063] As the first main connecting means 151, 152 respectively linking the first movable hood to the first fixed hood and the second movable hood to the second fixed hood are identical, only the first main connecting means 151 linking the first movable hood to the first fixed hood is detailed in what follows.

[0064] Figure 6 schematically illustrates a partial view of a first example of the first main connecting means 151 linking the first movable cover to the first fixed cover when the covers 6, 7, 8 are in the closed position. The first fitting 15a of the first main connecting means 151 is inserted into a first main housing 17 of the first movable cover 7 formed between the inner skin 11b and the outer skin 12b of the first movable cover 7.

[0065] The first main housing 17 opens onto the first side 13c of the first movable cover 7.

[0066] A first wall 18 of the first main housing 17 is formed by the inner skin 11b and a second wall 19 of the first main housing 17 is formed by the outer skin 12b. The first movable cover 7 further includes a seal 20 disposed on the inner skin 11b and on the first side 13a of the first cover 7.

[0067] The first wall 18 of the first main housing 17 extends towards the interior of the nacelle.

[0068] The first wall 18 may include two chamfers having an angle between 20° and 90°, the joint 20 covering said chamfers.

[0069] The first main connecting means 151 further includes a fixing means 21 fixed only on the outer skin 12b of the first movable cover 7 to hold the first fitting 15a in the first main housing 17.

[0070] Securing the first fitting 15a by means of the fastening 21 to the outer skin 12b of the first cover 7 avoids piercing the inner skin 11b so that the inner skin 11b is without an opening to ensure the fire tightness of the inner skin 11b.

[0071] The second fitting 15b of the first main connecting means 151 is inserted into a first main housing 22 of the fixed cover 6a formed between the inner skin 1la and the outer skin 12a of the fixed cover 6b.

[0072] The first main housing 22 opens onto the first side 13a of the fixed hood 6a.

[0073] A first wall 23 of the first main housing 22 is formed by the inner skin 1la and a second wall 24 of the first main housing 22 is formed by the outer skin 12a. The fixed cover 6a further includes a seal compressor 25 disposed on the inner skin 1la and on the first side 13a of the fixed cover 6a.

[0074] The seal compressor 25 cooperates with the seal 20 to ensure the seal between the hoods 6a, 7 in the closed position.

[0075] Alternatively, the seal 20 is disposed on the inner skin 11a of the fixed hood 6a and the seal compressor 25 is disposed on the inner skin 11b of the first movable hood 7.

[0076] The first main connecting means 151 further includes a fixing means 26 fixed only on the outer skin 12a of the fixed cover 6a to hold the second fitting 15b in the first main housing 22.

[0077] The fixing of the second fitting 15b by the fixing means 22 on the outer skin 12a of the fixed cover 6a makes it possible to avoid piercing the inner skin 1 la so that the inner skin 1 la is without an opening to guarantee the fire tightness of the inner skin lia.

[0078] The first and second fittings 15a, 15b are connected to each other by an axis 27 passing through a hole in each fitting 15a, 15b to form a pivot joint in order to articulate the first movable cover 7 relative to the fixed cover 6a.

[0079] The first movable hood 7 is articulated around the pivot joint to free up space in order to carry out, for example, maintenance of the turbomachine 5.

[0080] Fig. 7 schematically illustrates the first hood 7 in the open position around the pivot joint.

[0081] Fig. 8 schematically illustrates a partial view of a second example of the first main connecting means 151 linking the first movable hood to the first fixed hood when the hoods 6, 7 are in the closed position.

[0082] In this embodiment, the first fitting 15a includes a hook 28 and the second fitting 15b includes a stop 29.

[0083] In addition, the second side 14a of the first movable hood 7 is connected to an element of the propulsion assembly 2 by a pivot joint (not shown).

[0084] When the hoods 6a, 7 are in the closed position, the hook 28 fits into the stop 29.

[0085] When the hood 7 is opened to the open position ([Fig.9]), the hook 28 disengages via the pivot link connecting the second side 14a of the first movable hood 7 to the element of the propulsion assembly 2.

[0086] The hook 29 allows for the support of circumferential structural forces and reduces the overall size of the joint compared to a pivot joint. Figure 10 schematically illustrates a partial view of an example embodiment of the second main connecting means 16 linking the first and second movable covers 7, 8 in the closed position.

[0087] The first fitting 16a of the second main connecting means 16 is inserted into a second main housing 30 of the first movable cover 7 formed between the inner skin 11b and the outer skin 12b of the first movable cover 7.

[0088] The second main housing 30 opens onto the second side 14a of the first movable cover 7.

[0089] A first wall 31 of the second main housing 30 is formed by the inner skin 11b and a second wall 32 of the second main housing 30 is formed by the outer skin 12b.

[0090] The first hood 7 further includes a seal 32 disposed on the inner skin 11b and the second side 14a of the first hood 7.

[0091] The first wall 31 of the second main housing 30 extends into the nacelle.

[0092] The first wall 31 may include two chamfers having an angle between 20° and 90°, the joint 32 covering said chamfers.

[0093] The second main connecting means 16 further includes a fixing means 33 fixed only on the outer skin 12b of the first movable cover 7 to hold the first fitting 16a in the second main housing 30.

[0094] The fixing of the first fitting 16a by the fixing means 33 on the outer skin 12 of the first cover 7 makes it possible to avoid piercing the inner skin 11b so that the outer skin 11b is without an opening to guarantee the fire tightness of the inner skin 11b.

[0095] The second fitting 16b of the second main connecting means 16 is inserted into a second main housing 34 of the second movable cover 8 formed between the inner skin 11 and the outer skin 12c of the second movable cover 8.

[0096] The second main housing 34 opens onto the second side 14b of the second movable cover 8.

[0097] A first wall 35 of the second main housing 34 is formed by the inner skin 1a and a second wall 36 of the second main housing 34 is formed by the outer skin 12a. The second movable cover 8 further comprises a seal compressor 36 disposed on the inner skin 1 la and on the second side 14b of the second movable hood 8.

[0098] The seal compressor 36 cooperates with the seal 32 to ensure the seal between the first and second movable covers 7, 8 in the closed position.

[0099] Alternatively, the seal 32 is disposed on the inner skin 11a of the second movable cover 8 and the seal compressor 36 is disposed on the inner skin 11b of the first movable cover 7.

[0100] The second main connecting means 16 further includes a fixing means 37 fixed only on the outer skin 12a of the second movable cover 8 to hold the second fitting 16b in the second main housing 34.

[0101] The fixing of the second fitting 16b by the fixing means 37 on the outer skin 12a of the second movable cover 8 makes it possible to avoid piercing the inner skin 1 le so that the inner skin 1 le is without an opening to guarantee the fire tightness of the inner skin 11c.

[0102] The first fitting 16a includes a hook 38 and the second fitting 16b includes a receptacle cooperating with the hook 38 so that the hook engages in the receptacle to hold the movable hoods 7, 8 together.

[0103] The hook 38 includes a lever.

[0104] The outer skin 12b of the first movable cover 7 further includes a window (not shown) arranged under the lever of the hook 30 to allow manipulation of the lever through the window.

[0105] Fig. 11 schematically illustrates the first and second hoods 7, 8 in the open position.

[0106] The first movable hood 7 and / or the second movable hood 8 may include an inspection window closed by a hatch to access the interior of the nacelle by opening the hatch.

[0107] Maintenance and inspection operations can be carried out through the inspection window when the hatch is removed.

[0108] Fig. 12 schematically illustrates an example of the realization of an inspection window 40 closed by a hatch 41 arranged in the first movable cover 7.

[0109] A first secondary housing 42 and a second secondary housing 43 are formed between the inner skin 11b and the outer skin 12b of the first movable cover 7.

[0110] The first secondary housing 42 opens onto a first side 40a of the inspection window 40 and the second secondary housing 43 opens onto a second side 40b of the inspection window 40, the second side 40b being opposite the first side 40a.

[0111] A first wall 44 of the first secondary housing 42 is formed by the inner skin 11b and a second wall 45 of the first secondary housing 42 is formed by the outer skin 12b.

[0112] A first wall 46 of the second secondary housing 43 is formed by the inner skin 11b and a second wall 47 of the second secondary housing 43 is formed by the outer skin 12b.

[0113] The first secondary housing 42 houses an auxiliary linking means for fixing the inspection hatch 41 on the first movable cover 7, and the second secondary housing 43 houses a joint forming a pivot link between the inspection hatch 41 and the first movable cover 7 so that the inspection hatch 41 closes the inspection window 40.

[0114] The first connecting means comprises a first fitting 48 fixed on the outer skin 12b and forming a stop, and a second fitting 49 fixed on the hatch 41 and comprising a lock.

[0115] The joint comprises a first fitting 52 fixed on the outer skin 12b, and a second fitting 53 fixed on the hatch 41, the first fitting 52 and a second fitting 53 being connected by an axle 52.

[0116] The lock 49 comes to rest against the first fitting 48 so that the inspection window 40 is closed by a hatch 41 (closed position).

[0117] Seals 53 are arranged on the sides of the inspection window 40 and are compressed by the hatch 41 in the closed position.

[0118] In the open position ([Fig. 13]), when the lock 42 is released, the hatch 41 pivots around the pivot joint and releases the inspection window 40 allowing access into the gondola.

[0119] The inner skin 1 la, 11b, 1 le of the nacelle hoods 6a, 7, 8 made of composite protects the fittings from a fire starting in or near the turbomachine.

[0120] As the fittings are protected from fire, the main connecting means, the second main connecting means and the auxiliary connecting means can be made of aluminium so that the mass of the fittings is reduced and the costs of the fittings are reduced.

[0121] Furthermore, as the internal skin 1 la, 11b, 1 le of the nacelle hoods 6a, 7, 8 made of composite acts as fire protection and the joint is not interrupted by the fittings, the thermal screen known from the prior art can be removed, freeing up space in the nacelle and reducing the aircraft's onboard mass.

[0122] In addition, like the means for fixing the main connecting means, the second main connecting means and the auxiliary connecting means are fixed on the outer skin 12a, 12b, 12c of the hoods 6a, 7, 8, the fittings are cooled by conduction by the ambient air.

[0123] As the fittings are arranged on the outer skin, the fitting of the fittings is simplified.

[0124] Of course, the inner skin 1 la, 11b, 1 le may include a thermal screen.

[0125] According to another embodiment, the inner skin 1 la, 11b, 1 le can report on the external skin 12a, 12b, 12c.

Claims

Demands

1. A nacelle (4) cowl (6a, 7, 8, 9, 10) for an aircraft (1) comprising a propulsion unit (2), the cowl comprising an inner skin (1la, 11b, 1le) made of composite materials and configured to cover at least a part of a turbomachine (5) of the propulsion unit, and an outer skin (12a, 12b, 12c) made of composite materials and opposed to the inner skin, characterized in that at least one first main housing (17, 22) is formed between the inner skin and the outer skin, the first main housing opening onto a first side (13a, 13c) of the cowl and housing a first main connecting means (151, 152) configured to fix the cowl to an element of the propulsion unit (2).

2. Hood according to claim 1, comprising at least a second main housing (30, 34) formed between the inner skin (11) and the outer skin (12), the second main housing opening onto a second side (14a, 14b) of the hood opposite the first side and housing a second main connecting means (16) configured to fix the hood to another hood of the nacelle.

3. Hood according to claim 2, wherein the second main connecting means (16) includes a receptacle (39) configured to cooperate with a hook (38).

4. Hood according to claim 2, wherein the second main connecting means (16) includes a hook (38) configured to cooperate with a receptacle (39).

5. Hood according to any one of claims 1 to 4, wherein a first wall (23, 18) of each main housing (20, 26) is formed by the inner skin (11) and a second wall (24, 19) of each main housing is formed by the outer skin (12).

6. Hood according to any one of claims 1 to 5, wherein a seal (20, 32) or a seal compressor (25, 36) is disposed on the inner skin and on each side of the hood (13a, 13c, 14a, 14b).

7. Hood according to any one of claims 1 to 6, wherein the first main connecting means (151, 152) comprises a joint (15a, 15b, 27, 29) configured to form a pivot connection between the hood (7, 8) and the element of the propulsion assembly (6, 6a).

8. A hood according to any one of claims 1 to 7, further comprising at least one inspection window (40), an inspection hatch (41), a

9.

10. first secondary housing (42) formed between the inner skin (11b) and the outer skin (12b) and a second secondary housing (43) formed between the inner skin (11b) and the outer skin (12b), the first secondary housing (42) opening onto a first side (40a) of the inspection window and the second secondary housing (43) opening onto a second side (40b) of the inspection window, the second side being opposite the first side, the first secondary housing (42) housing an auxiliary linking means (48, 49) configured to fix the inspection hatch (41) on the hood (7) and the second secondary housing (43) housing a hinge (50, 51, 52) configured to form a pivot link between the inspection hatch (41) and the hood (7) so that the inspection hatch closes the inspection window. Hood according to any one of claims 1 to 8, wherein each connecting means (16, 48, 49, 50, 51, 52, 151, 152) comprises a fastening means (21, 26, 33, 37) fixed to the outer skin (12b, 12c) to hold said connecting means in its housing. Hood according to claim 9, wherein the fastening means (21, 26, 33, 37) is fixed only on the outer skin (12b, 12c).

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