Method for manufacturing an aerodynamic panel for an aircraft propulsion assembly

Abstract

The invention relates to a method for manufacturing an aerodynamic panel (32) for an aircraft propulsion assembly (10), the method comprising the following steps: a) applying at least one reinforcement plate (38, 42, 44) to a first face (34a) of a wall (34); b) rigidly attaching the reinforcement plate (38, 42, 44) to the wall (34, 36) by friction stir welding; c) producing through-holes (50) through the wall (34) and the reinforcement plate (38, 42, 44), these holes (50) being formed through the weld seam (40); and d) fitting screws (52, 54, 56) into the holes (50), these screws (52, 54, 56) comprising countersunk heads (58) that have a thickness (H) greater than the thickness (E1) of the wall (34) and less than the thickness (E3) of the weld seam (40).

Description

[0001] DESCRIPTION

[0002] TITLE: METHOD FOR MANUFACTURING AN AERODYNAMIC PANEL FOR AN AIRCRAFT PROPULSION ASSEMBLY

[0003] Technical field of the invention

[0004] The present invention relates to a method of manufacturing an aerodynamic panel for an aircraft propulsion assembly, as well as an aerodynamic panel obtained by this method.

[0005] Technical background

[0006] The technical background includes in particular documents US-B2-9,845,728, US-A1 -2015 / 291273 and US-B1 -6,213,379.

[0007] A propulsion unit comprises a turbomachine surrounded by a nacelle. The propulsion unit comprises aerodynamic panels which are panels intended in operation to be swept by one or more gas flows flowing along the propulsion unit. These panels may be cowls of the nacelle intended to be swept by a gas flow external to the propulsion unit, or casings of the turbomachine intended to be swept by a secondary flow for example.

[0008] An aerodynamic panel comprises an aerodynamic face capable of being swept by the gas flow. This panel is fixed to the nacelle or the turbomachine by screws which pass through the panel. Elements can also be fixed to a panel of this type by screws.

[0009] The panel should preferably be as thin as possible to limit its mass. However, this thickness should not be too thin at the screws to withstand the forces in the areas where the panel or elements are fixed.

[0010] To get around this problem, it is known to use a thick panel and machine it so as to leave excess thickness only in the fixing areas with holes for the fixing screws.

[0011] Another solution could be to attach a reinforcement plate to the wall. The reinforcement plate would be attached to the face of the panel opposite its aerodynamic face, and this reinforcement plate would include holes aligned with the holes in the wall, for the passage of the fixing screws.

[0012] The screws are countersunk screws, i.e. screws whose heads have a generally truncated cone shape and are intended to be engaged in flared parts of the holes located on the side of the aerodynamic face of the wall. The larger the diameter of the screws, the greater the axial dimension or thickness of their countersunk heads. In current technology, it is not possible to use screws whose countersunk heads have a thickness or axial dimension greater than 2 / 3 of the thickness of the panel because the resulting assembly would not be optimal since the panel would not be correctly tightened by the screws on the reinforcement plate.

[0013] The present invention provides a simple, effective and economical solution to this problem.

[0014] Summary of the invention

[0015] The present invention relates to a method for manufacturing an aerodynamic panel for an aircraft propulsion assembly, the method comprising the following steps: a) applying at least one reinforcing plate to a first face of a wall, the reinforcing plate covering a portion of this first face and the wall comprising a second face, opposite the first face, which is a face capable of being swept by a gas flow when the panel is mounted in a propulsion assembly, b) securing the reinforcing plate and the wall by friction stir welding using a tool comprising a welding head which is moved over the second face so as to create a weld bead which extends in thickness from the second face over an entire thickness of the wall and over at least a portion of a thickness of the reinforcing plate, c) making through holes through the wall and the reinforcing plate, these holes being formed through the weld bead,and (d) mounting screws in the holes, these screws having countersunk heads which are located on the side of said second face and aligned with this face, these countersunk heads having a thickness or axial dimension less than said thickness of the weld bead.,

[0016] In the present application, the (axial) thickness or axial dimension of the countersunk heads is measured along the axes of elongation of the screws. To the extent that the screws pass through the wall and the reinforcing plate, they extend into the thicknesses of these elements. It is therefore understood that the thicknesses of the wall, the reinforcing plate, the weld bead, and the screws are measured in directions parallel and generally perpendicular to the faces of the wall.

[0017] A first advantage of the invention is linked to the fact that the thickness of the countersunk heads, and therefore the diameter of the screws, is not limited by the thickness of the wall. This means that thinner walls than in the prior art can be used within the scope of the present invention, which is also advantageous in terms of mass and cost. The thickness of the weld bead is determined, on the one hand as a function of the thickness of the wall and on the other hand as a function of the thickness or axial dimension of the countersunk heads of the screws. The thickness of the weld bead is greater than the thickness of the wall so that the weld bead extends into the reinforcing plate and secures it to the wall. The thickness of the weld bead is also greater than the thickness or axial dimension of the countersunk heads of the screws so that they are entirely housed in thickness in the weld bead.Finally, the thickness or axial dimension of the countersunk heads of the screws is greater than the thickness of the wall to ensure optimal support of the wall and the reinforcement plate.

[0018] Advantageously, the countersunk heads have a thickness or axial dimension greater than 2 / 3 of the thickness of the weld bead.

[0019] According to the invention, the welding is carried out by friction stir welding (or FSW, which is the acronym for Friction Stir Welding). This type of welding is advantageous because it does not require filler material. Furthermore, this type of welding does not generate a protruding weld bead. On the contrary, the weld bead produced is relatively flat and generally has a free external surface which is aligned with the face of the wall over which the head of the welding tool is moved. The face of the wall may, however, undergo a sanding and / or finishing operation to perfect its surface condition.

[0020] The double fixing of the wall and the reinforcement plate, by means of the welding bead and the screws, improves the transmission of forces and therefore the lifespan of the panel.

[0021] The method according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another:

[0022] - the weld bead is made in a single pass in step b);

[0023] - the method comprises, after step d), a step e) of fixing an element on the reinforcement plate, on the side opposite said wall, this element comprising holes crossed by said screws which receive nuts which are screwed onto the screws and which bear on the element;

[0024] - the element is a fitting or a fishplate;

[0025] - the method comprises, between steps b) and c), a step i) of sanding a free external surface of the weld bead;

[0026] - the panel has a thickness, preferably constant, of between 1 and 3 mm, and preferably between 1.5 and 2 mm;

[0027] - the welding codon has a width between 5 and 15 mm;

[0028] - the welding codon has a thickness between 1.5 and 4 mm, and preferably between 1.5 and 3 mm;

[0029] - the countersunk heads have a thickness or axial dimension greater than 2 / 3 (two thirds) of the said thickness of the weld bead;

[0030] - the wall and the reinforcing plate are made of metallic materials, and are for example made of the same metallic alloy; -- the reinforcing plate has a thickness greater than that of the wall; alternatively, its thickness could be identical or less;

[0031] -- the reinforcement plate has a thickness, preferably constant, between 2 and 4 mm.

[0032] The present invention also relates to an aerodynamic panel for an aircraft propulsion unit, this panel being obtained by the method described above and comprising: - a wall comprising a first face and a second face opposite the first face, this second face being capable of being swept by a flow of gas when the panel is mounted in a propulsion unit,

[0033] - a reinforcing plate which covers part of this first face and which is secured to the wall by a weld bead, this weld bead comprising a free external surface which is aligned with said second face, this weld bead comprising holes passing through the wall and the reinforcing plate, and

[0034] - screws mounted in the holes and comprising countersunk heads which are located on the side of said second face and aligned with this face and the free external surface of the weld bead, these countersunk heads having a thickness or axial dimension greater than a thickness of the wall and less than a thickness of the weld bead.

[0035] The panel according to the invention may comprise one or more of the following characteristics, taken in isolation from one another or in combination with one another:

[0036] -- the panel has a thickness, preferably constant, of between 1 and 3 mm, and preferably between 1.5 and 2 mm;

[0037] -- the welding bead has a width between 5 and 15mm;

[0038] -- the welding bead has a thickness between 1.5 and 4 mm, and preferably between 1.5 and 3 mm;

[0039] -- the countersunk heads have a thickness or axial dimension greater than 2 / 3 (two-thirds) of the said thickness of the weld bead;

[0040] -- the wall and the reinforcing plate are made of metallic materials, and are for example made of the same metallic alloy; -- the reinforcing plate has a thickness greater than that of the wall; alternatively, its thickness could be identical or less;

[0041] -- the reinforcement plate has a thickness, preferably constant, between 2 and 4 mm.

[0042] The present invention also relates to an aircraft propulsion assembly, comprising an aerodynamic panel as described above.

[0043] Brief description of the figures Other characteristics and advantages of the invention will appear during the reading of the detailed description which follows for the understanding of which one will refer to the appended drawings in which:

[0044] [Fig.1] Figure 1 is a half schematic view in axial section of an aircraft propulsion unit,

[0045] [Fig.2] Figure 2 is a schematic perspective view of an embodiment of an aerodynamic panel according to the invention,

[0046] [Fig.3] Figure 3 is a block diagram illustrating an embodiment of a manufacturing method according to the invention,

[0047] [Fig.4] Figure 4 is a sectional view of the panel of Figure 2,

[0048] [Fig.5] Figure 5 is an enlarged view of part of Figure 3, [Fig.6] Figure 6 is a view similar to that of Figure 4 and showing dimensions,

[0049] [Fig.7a] Figure 7a is a schematic view of a countersunk head of a first embodiment of a fixing screw, and

[0050] [Fig.7b] Figure 7b is a schematic view of a countersunk head of a second embodiment of a fixing screw.

[0051] Detailed description of the invention

[0052] Figure 1 shows a propulsion unit 10 for an aircraft, this propulsion unit 10 comprising a turbomachine 12 surrounded by a nacelle 14.

[0053] The turbomachine 12 is here of the double flow type. This is not however limiting and the turbomachine 12 can be of another type, such as for example a turboprop.

[0054] The turbomachine 12 extends along a longitudinal axis X and comprises from upstream to downstream, in the direction of gas flow, a fan 16, one or more compressor stages (for example a low-pressure compressor 18 and a high-pressure compressor 20), an annular combustion chamber 22, one or more turbine stages (for example a high-pressure turbine 24 and a low-pressure turbine 26), and a gas exhaust nozzle 28.

[0055] The blower 16, the low-pressure compressor 18 and the low-pressure turbine 26 are connected to a low-pressure shaft extending along the longitudinal axis X. The high-pressure compressor 20 and the high-pressure turbine 24 are connected to a high-pressure shaft arranged around the low-pressure shaft. The low-pressure turbine 26 drives the low-pressure shaft to rotate, while the high-pressure turbine 26 drives the high-pressure shaft to rotate.

[0056] The nacelle 14 is centered on the longitudinal axis X and defines an annular vein around the turbomachine 12.

[0057] The gas flow F which passes through the fan 16 inside the nacelle 14 is divided downstream of the fan 2 into two annular and coaxial flows. A first flow, called primary flow F1, flows into the turbomachine and is compressed in the compressors 18, 20, mixed with fuel and burned in the combustion chamber 22, then expanded in the turbines 24, 26, to finally be discharged through the nozzle 28. A second flow, called secondary flow F2, flows in the annular vein around the turbomachine 12 and can provide the majority of the thrust of the turbomachine in particular when the latter is of the high bypass ratio type.

[0058] Furthermore, a flow of gas F3 flows around the nacelle 14 in operation.

[0059] The propulsion assembly 10 comprises aerodynamic panels which are panels intended in operation to be swept by one or more gas flows flowing along the propulsion assembly 10. These panels may be cowls of the nacelle 14 intended to be swept by the gas flow F3, casings of the turbomachine 12 intended to be swept by the secondary flow F2, etc.

[0060] The present invention provides an improvement to such a panel, as well as to its manufacturing method.

[0061] Figure 2 illustrates an embodiment of a panel 32 according to the invention and Figure 3 illustrates an example of a method of manufacturing this panel 32.

[0062] The panel 32 comprises a wall 34 comprising a first face 34a and a second face 34b opposite the first face 34a. This second face 34b is capable of being swept by a gas flow when the panel 32 is mounted in the propulsion assembly 10, as mentioned above. The panel 32 may comprise one or more other walls 36. It may for example comprise another adjacent wall 36, which is arranged next to the wall 34 and aligned with it. The two walls 34, 36 are for example intended to be fixed or secured to each other.

[0063] As is the case with the wall 34, the wall 36 comprises a first face 36a and a second face 36b opposite the first face 36a. This second face 36b is capable of being swept by a gas flow when the panel 32 is mounted in the propulsion assembly 10, as mentioned above. The faces 34b and 36b are intended to be aligned together.

[0064] Walls 34 and 36 may be identical.

[0065] The or each wall 34, 36 has a generally parallelepiped shape in the example shown, even if this aspect is not limiting.

[0066] The or each wall 34, 36 has a thickness, preferably constant, of between 1 and 3 mm, and preferably between 1.5 and 2 mm. This thickness is noted E1 in figure 6.

[0067] The or each wall 34, 36 is made of metallic materials. They are preferably made of the same metallic alloy, for example based on aluminum or titanium.

[0068] The or each wall 34, 36 may be flat, as in the example shown, or curved.

[0069] The panel 32 further comprises at least one reinforcing plate 38 which covers a portion of the first face 34a of the wall 34 and which is secured to this wall 34 by a weld bead 40.

[0070] The reinforcing plate 38 therefore extends over only part of the face 34a, and is therefore located in an area which must be reinforced. The plate 38 therefore locally reinforces the wall 34.

[0071] The panel 32 may comprise one or more other reinforcing plates 42, 44. It may for example comprise another reinforcing plate 42 which is arranged on the face 34a of the wall 34, along an edge adjacent to the wall 36, and another reinforcing plate 44 which is arranged on the face 36a of the wall 36, along an edge adjacent to the wall 34.

[0072] Each of the reinforcing plates 38, 42, 44 is secured to the wall 34, 36 by a weld bead 40. Each of the reinforcing plates 38, 42, 44 has a first face applied against the face 34a, 36a of the wall 34 or 36, and a second face 40b opposite the first face (see figures 4 and 5).

[0073] This second face 40b is capable of receiving an element to be fixed.

[0074] In the example shown, the second face 40b of the reinforcing plate 38 receives a fitting 46, and the second faces 40b of the reinforcing plates 42, 44 receive a fishplate 48 which is applied to these two faces 40b.

[0075] The or each reinforcing plate 38, 42, 44 has a generally parallelepiped shape in the example shown, even if this aspect is not limiting.

[0076] The or each reinforcing plate 38, 42, 44 has a thickness, preferably constant, and advantageously greater than the thickness E1 of the or each wall 34, 36. The or each reinforcing plate 38, 42, 44 has a thickness preferably between 2 and 4 mm. This thickness is noted E2 in figure 6.

[0077] The or each reinforcing plate 38, 42, 44 is made of metallic materials. They are preferably made of the same metallic alloy as the walls 34, 36, for example based on aluminum or titanium.

[0078] The or each reinforcing plate 38, 42, 44 may be flat, as in the example shown, or curved.

[0079] The panel 32 further comprises holes 50 for mounting screws 52, 54, 56 for fixing the aforementioned elements, such as the fitting 46 and the fishplate 48.

[0080] The holes 50 are through and are formed in the or each wall 34, 36 and in the or each reinforcing plate 38, 42, 44, as well as in the elements to be fixed.

[0081] In the example shown, the reinforcing plate 38 comprises two holes 50 which are aligned with two holes 50 of the wall 34 and two holes of the fitting 46. These holes 50 receive fixing screws 52. The reinforcing plate 42 comprises eight holes 50 which are aligned with eight holes of the wall 34 and eight holes of the fishplate 48. These holes 50 receive fixing screws 54. The reinforcing plate 44 comprises eight holes 50 which are aligned with eight holes of the wall 36 and eight other holes of the fishplate 48. These holes 50 receive fixing screws 56. Each of the screws 52, 54, 56 is of the countersunk head type and comprises a countersunk head 58 located at one end of a rod 60 which is at least partly threaded (see FIG. 5). The rod 60 passes through the holes 50 and the countersunk head 58 is housed in a flare 50a of the hole 50 formed in the wall 34, 36.The countersunk head 58 is intended to be entirely housed in this flare 50a, as can be seen in the drawings, so that its end surface 58b is aligned with the face 34b, 36b of the wall 34, 36.

[0082] As can be seen in Figures 7a and 7b, this end surface 58b may comprise a hollow imprint 61 to allow engagement with a tightening / loosening tool of the screw 52, ​​54, 56, in particular when the latter is of the disassembly type. Alternatively, the screw 52, ​​54, 56 is of the non-disassemblable type and does not comprise an imprint on its end surface 58b which is then smooth.

[0083] The rod 60 of each screw 52, ​​54, 56 receives a nut 62 which is screwed and tightened against the element to be fixed. In the case where the screw 52, ​​54, 56 is of the non-removable type, the end of the rod 60, opposite the countersunk head 58, may comprise an imprint 61 for engagement with a tool for immobilizing the screw in rotation during the screwing and tightening of the nut 62 (see figure 5). The or each screw 52, ​​54, 56 has a diameter denoted D in figure 6, this diameter being that of its rod 60. The diameter of the screw head 58 is denoted A.

[0084] The countersunk head 58 of the or each screw 52, ​​54, 56 has a thickness or axial dimension (along the axis of elongation of the screw) which is noted H.

[0085] Preferably, H is greater than E1 and is between E1 and E1+E2.

[0086] The panel 32 further comprises weld beads 40 for securing the reinforcing plates 38, 42, 44 to the walls 34, 36, as mentioned above.

[0087] In the example shown, a first weld bead 40 is formed between the wall 34 and the reinforcing plate 38. A second weld bead 40 is formed between the wall 34 and the reinforcing plate 42, along the aforementioned edge of the wall 34, and a third weld bead 40 is formed between the wall 36 and the reinforcing plate 44, along the aforementioned edge of the wall 36.

[0088] Each of the weld beads 40 has a generally elongated shape. Each weld bead 40 may be made in a single pass. Alternatively, the weld bead 40 could be made in two or more passes.

[0089] The particularity of each weld bead 40 is that it is formed by friction stir welding (or FSW welding). This welding technique is known to those skilled in the art of welding and will not be described in detail in the following.

[0090] The weld bead 40 has a free external surface 40a which is aligned with the second face 34b, 36b of the corresponding wall 34, 36. The weld bead 40 extends in thickness from this face 34b, 36b over the entire thickness E1 of the wall 34, 36 and over at least a portion of the thickness E2 of the reinforcing plate 38, 42, 44 (Figures 5 and 6).

[0091] The thickness of the weld bead 40 is noted E3 in figure 6. It is for example between 1.5 and 4 mm, and preferably between 1.5 and 3 mm.

[0092] The weld bead 40 has a width (measured in a direction transverse to the axis of elongation of the weld bead) which is greater than D and A. D and A may be between 4 and 12 mm. The width, denoted L in FIG. 6, of the weld bead 40 is preferably between 5 and 15 mm.

[0093] Preferably, H is less than or equal to E3 and more preferably strictly less than E3.

[0094] Preferably, H is greater than 2 / 3 of E3.

[0095] Preferably, H is greater than or equal to E1 + 1 / 3 x E1.

[0096] According to the invention, the holes 50 are formed in the weld bead 40, as shown in the drawings. The holes 50 are therefore formed in the panel 32 after welding.

[0097] Figure 3 illustrates a method of manufacturing a panel 32 according to one embodiment of the invention.

[0098] The process includes several steps, some of which are optional.

[0099] The method comprises in particular the following steps: a) applying at least one reinforcing plate 38, 42, 44 to a first face 34a of a wall 34, the reinforcing plate 38, 42, 44 covering a portion of this first face 34a and the wall 34 comprising a second face 34b, opposite the first face, which is a face capable of being swept by a gas flow when the panel 32 is mounted in a propulsion unit, b) securing the reinforcing plate 38, 42, 44 and the wall 34 by friction stir welding using a tool comprising a welding head which is moved over the second face 34b so as to create a weld bead 40 which extends in thickness from the second face 34b over an entire thickness E1 of the wall 34 and over at least a portion of a thickness E2 of the reinforcing plate 38, 42, 44, c) making through holes 50 through the wall 34 and the reinforcement plate 38, 42, 44, these holes 50 being formed through the weld bead 40,and d) mounting screws 52, 54, 56 in the holes 50, these screws 52, 54, 56 comprising countersunk heads 58 which are located on the side of the second face 34b and aligned with this face 34b, these countersunk heads 58 having a thickness H or axial dimension greater than the thickness E1 of the wall 34 and less than the thickness E3 of the weld bead 40.,

[0100] As mentioned above, the weld bead 40 can be made in a single pass in step b).

[0101] The method may comprise, after step d), a step e) of fixing an element on the reinforcing plate 38, 42, 44, on the side opposite the wall 34, this element comprising holes 50 crossed by the screws 52, 54, 56 which receive nuts 62 which are screwed onto the screws 50 and which bear on the element. The element is for example a fitting 46 or a fishplate 48.

[0102] The method may comprise, between steps b) and c), a step i) of sanding the free external surface 40a of the weld bead 40.

[0103] The present invention makes it possible in particular to obtain optimized panels meeting the right needs in terms of mass, cost and integration of fixings.

Claims

CLAIMS 1. Method for manufacturing an aerodynamic panel (32) for an aircraft propulsion unit (10), the method comprising the following steps: a) applying at least one reinforcing plate (38, 42, 44) to a first face (34a) of a wall (34), the reinforcing plate (38, 42, 44) covering a portion of this first face (34a) and the wall (34) comprising a second face (34b), opposite the first face (34a), which is a face capable of being swept by a gas flow when the panel (32) is mounted in a propulsion unit (10), b) securing the reinforcing plate (38, 42, 44) and the wall (34, 36) by friction stir welding using a tool comprising a welding head which is moved over the second face (34b) so as to create a weld bead (40) which extends in thickness from the second face (34b) over an entire thickness (E1) of the wall (34) and over at least part of a thickness (E2) of the reinforcement plate (38, 42, 44),c) making through holes (50) through the wall (34) and the reinforcement plate (38, 42, 44), these holes (50) being formed through the weld bead (40), and d) mounting screws (52, 54, 56) in the holes (50), these screws (52, 54, 56) having countersunk heads (58) which are located on the side of said second face (34b) and aligned with this face (34b), these countersunk heads (58) having a thickness (H) or axial dimension greater than said thickness (E1) of the wall (34) and less than said thickness (E3) of the weld bead (40)., 2. Method according to claim 1, in which the weld bead (40) is produced in a single pass in step b).

3. Method according to claim 1 or 2, in which it comprises, after step d), a step e) of fixing an element on the reinforcing plate (38, 42, 44), on the side opposite to said wall (34), this element comprising holes (50) crossed by said screws (52, 54, 56) which receive nuts (62) which are screwed onto the screws (52, 54, 56) which bear on the element.

4. Method according to claim 3, in which the element is a fitting (58) or a fishplate (60).

5. Method according to one of the preceding claims, in which it comprises, between steps b) and c), a step i) of sanding a free external surface (40a) of the weld bead (40).

6. Method according to one of the preceding claims, in which the panel (34) has a thickness (E1), preferably constant, of between 1 and 3 mm, and preferably between 1.5 and 2 mm.

7. Method according to one of the preceding claims, in which the welding codon (40) has a width (L) of between 5 and 15 mm.

8. Method according to one of the preceding claims, in which the welding codon (40) has a thickness (E3) of between 1.5 and 4 mm, and preferably between 1.5 and 3 mm.

9. Method according to one of the preceding claims, in which the countersunk heads (58) have a thickness (H) or axial dimension greater than 2 / 3 of said thickness (E3) of the weld bead (40).

10. Method according to one of the preceding claims, in which the wall (34) and the reinforcing plate (38, 42, 44) are made of metallic materials, and are for example made of the same metallic alloy.

11. Aerodynamic panel (32) for an aircraft propulsion unit (10), this panel (32) being obtained by the method according to one of the preceding claims and comprising: - a wall (34) comprising a first face (34a) and a second face (34b) opposite the first face (34a), this second face (34b) being capable of being swept by a flow of gas when the panel (32) is mounted in a propulsion unit (10), - a reinforcing plate (38, 42, 44) which covers a part of this first face (34a) and which is secured to the wall (34) by a weld bead (40), this weld bead (40) comprising a free external surface (40a) which is aligned with said second face (34b), this weld bead (40) comprising holes (50) passing through the wall (34) and the reinforcing plate (38, 42, 44), and - screws (50) mounted in the holes (50) and comprising countersunk heads (58) which are located on the side of said second face (34b) and aligned with this face (34b) and the free external surface (40a) of the weld bead (40), these countersunk heads (58) having a thickness (H) or axial dimension greater than a thickness (E1) of the wall (34) and less than a thickness (E3) of the weld bead (40).

12. Aircraft propulsion assembly (10), comprising an aerodynamic panel (32) according to claim 11.

Images