Aircraft engine nacelle middle section skin

Abstract

An aircraft engine nacelle middle-section skin comprises a middle-section upper wall plate, a middle-section left wall plate, a middle-section right wall plate and a mounting beam, and the mounting beam is of a U-shaped structure and is arranged at the front ends of the middle-section upper wall plate, the middle-section left wall plate and the middle-section right wall plate; the left end of the middle-section upper wall plate is connected with the middle-section left wall plate through a quick-release lock, the right end of the middle-section upper wall plate is connected with the middle-section right wall plate through a quick-release lock, and the front end of the middle-section upper wall plate is connected with the mounting beam through a quick-release lock; the mounting beam is located below the upper wallboard skin, the left wallboard skin and the right wallboard skin, and the front end of the left wallboard skin and the front end of the right wallboard skin are connected with the mounting beam through rivets. Through the arrangement, when the engine needs to be overhauled, the middle section upper wall plate is convenient to disassemble, and the working efficiency is greatly improved.

Description

Technical Field

[0001] The utility model belongs to the technical field of aircraft manufacturing, and particularly relates to a front skin of a short nacelle of an aircraft engine. Background Technique

[0002] An aircraft skin refers to a conical member that surrounds the aircraft frame structure and is fixed to the frame with an adhesive or rivets to form the aerodynamic shape of the aircraft. The aircraft skin consists of multiple parts, and the connection of the skins of each part ensures the overall stiffness and strength of the aircraft, while maintaining the aerodynamic shape of the aircraft, thereby ensuring the aerodynamic performance of the aircraft. In the prior art, the skins of various parts of the aircraft are mostly connected by riveting to provide stable connection performance throughout the service life of the aircraft. However, at the position of the short nacelle of the aircraft engine, since the engine needs to be frequently overhauled, the upper part of the middle-section skin of the engine nacelle needs to be disassembled. In the prior art, all parts of the aircraft engine nacelle are connected by rivets, which is time-consuming and laborious for disassembly and assembly, and reduces work efficiency. Content of the Utility Model

[0003] In view of this, the utility model discloses a middle-section skin of an aircraft engine nacelle, which realizes quick disassembly and assembly of the middle-section skin of the engine nacelle and improves the installation efficiency. The specific scheme is as follows:

[0004] A middle-section skin of an aircraft engine nacelle includes a middle-section upper wall panel, a middle-section left wall panel, a middle-section right wall panel, and an installation beam. The installation beam is of a U-shaped structure and is arranged at the front ends of the middle-section upper wall panel, the middle-section left wall panel, and the middle-section right wall panel;

[0005] The middle-section upper wall panel includes an upper wall panel skin;

[0006] The middle-section left wall panel includes a left wall panel skin and a first connecting plate. The first connecting plate is arranged on the lower surface of the left wall panel skin through rivets, and the right part of the first connecting plate protrudes from the right end of the left wall panel skin and extends below the upper wall panel skin, and is connected to the upper wall panel skin through a quick-release lock;

[0007] The middle-section right wall panel includes a right wall panel skin and a second connecting plate. The second connecting plate is arranged on the lower surface of the right wall panel skin through rivets, and the left part of the second connecting plate protrudes from the left end of the right wall panel skin and extends below the upper wall panel skin, and is connected to the upper wall panel skin through a quick-release lock;

[0008] The installation beam is located below the upper wall panel skin, the left wall panel skin, and the right wall panel skin, and the front ends of the upper wall panel skin, the left wall panel skin, and the right wall panel skin are all connected to the installation beam through quick-release locks.

[0009] As a supplement to the technical solution of the present utility model, the upper wall panel of the middle section further includes upper wall panel longitudinal beams and upper wall panel cross beams. There are three groups of the upper wall panel longitudinal beams, namely the first longitudinal beam, the second longitudinal beam, and the third longitudinal beam. The three groups of upper wall panel longitudinal beams are arranged in sequence from left to right on the lower bottom surface of the upper wall panel skin, and are all connected to the upper wall panel skin by rivets;

[0010] The upper wall panel cross beam includes a first short beam and a second short beam. The left end of the first short beam is connected to the first longitudinal beam, and the right end of the first short beam is connected to the second longitudinal beam; the left end of the second short beam is connected to the second longitudinal beam, and the right end of the second short beam is connected to the third longitudinal beam.

[0011] As a supplement to the technical solution of the present utility model, the second longitudinal beam includes a second longitudinal beam web. Bends are provided at both the upper end and the lower end of the second longitudinal beam web, so that the second longitudinal beam as a whole has a structure with a "U" - shaped cross - section with a notch, and the notch of the second longitudinal beam faces the direction of the first short beam;

[0012] The first short beam includes a first short beam web. Bends are provided at both the upper end and the lower end of the first short beam web, so that the cross - section of the first short beam is a "Z" - shaped structure; the bend provided at the upper end of the first short beam web is riveted to the skin. The right end of the first short beam is located within the notch of the second longitudinal beam. The bend at the upper end of the first short beam web is located below the bend at the upper end of the second longitudinal beam web, and the bend at the upper end of the first short beam web, the bend at the upper end of the second longitudinal beam web, and the upper wall panel skin are riveted;

[0013] The bend at the lower end of the first short beam web is located above the bend at the lower end of the second longitudinal beam web, and the bend at the lower end of the first short beam web and the bend at the lower end of the second longitudinal beam web are riveted.

[0014] As a supplement to the technical solution of the present utility model, the second short beam includes a second short beam web. Bends are provided at both the upper end and the lower end of the second short beam web. The bend at the upper end of the second short beam web is riveted to the upper wall panel skin, and the bend at the lower end of the second short beam web is connected to the bend at the lower end of the second longitudinal beam web through a connecting plate.

[0015] As a supplement to the technical solution of the present utility model, the upper wall panel cross beam further includes a first cross beam and a second cross beam. The first cross beam and the second cross beam are riveted to the lower bottom surface of the upper wall panel skin. The first cross beam is located at the front end of the first longitudinal beam, the second longitudinal beam, and the third longitudinal beam, and the second cross beam is located at the rear end of the first longitudinal beam, the second longitudinal beam, and the third longitudinal beam;

[0016] A bend is provided at the lower end of the first cross beam. The bend at the lower end of the first cross beam is located below the second longitudinal beam, and the bend at the lower end of the second longitudinal beam web is riveted to the bend at the lower end of the first cross beam;

[0017] The lower end of the second cross beam is provided with a bent edge, and the bent edge at the lower end of the second cross beam is located below the second longitudinal beam. The bent edge at the lower end of the web of the second longitudinal beam is riveted to the bent edge at the lower end of the second cross beam.

[0018] As a supplement to the technical solution of the present utility model, the left end of the first short beam is connected to the first longitudinal beam through an angle piece, and the right end of the second short beam is connected to the third longitudinal beam through an angle piece.

[0019] As a supplement to the technical solution of the present utility model, it further includes a left cabin door panel, a right cabin door panel, a left cabin door hinge, and a right cabin door hinge;

[0020] The left cabin door panel and the right cabin door panel have the same structure. The left cabin door panel includes a cabin door skin, cabin door ribs, and a cabin door hinge installation beam. The cabin door ribs are arranged inside the cabin door skin and are connected to the cabin door skin through rivets; the cabin door hinge installation beam is riveted to the inner surface of the left cabin door skin and is located at the upper end of the left cabin door skin, and the upper end of the cabin door ribs is riveted to the cabin door hinge installation beam;

[0021] The middle section left wall panel further includes a left wall panel hinge installation beam, and the left wall panel hinge installation beam is riveted to the inner surface of the left wall panel skin and is located at the lower end of the left wall panel skin,

[0022] The cabin door hinge installation beam and the left wall panel hinge installation beam are connected through a left cabin door hinge;

[0023] The middle section right wall panel further includes a right wall panel hinge installation beam, and the right cabin door panel is connected to the middle section right wall panel through a right cabin door hinge.

[0024] As a supplement to the technical solution of the present utility model, it further includes a tail cross beam. The tail cross beam is arranged at the rear ends of the middle section upper wall panel, the middle section left wall panel, and the middle section right wall panel. The rear ends of the upper wall panel skin, the left wall panel skin, and the right wall panel skin are all connected to the tail cross beam through quick-release locks.

[0025] Beneficial effects: By designing the middle section upper wall panel in the middle section skin of the aircraft engine nacelle to be detachably connected to the middle section left wall panel and the middle section right wall panel, when performing maintenance on the engine, only the quick-release lock for installing the upper wall panel skin needs to be disassembled to remove the middle section upper wall panel, improving work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 It is a three-dimensional structural schematic diagram of the present utility model.

[0027] Figure 2 It is a three-dimensional structural schematic diagram of the present utility model.

[0028] Figure 3 It is a three-dimensional structural schematic diagram of the present utility model.

[0029] Figure 4 This is a three-dimensional structural schematic diagram of the present utility model.

[0030] Figure 5 This is a structural schematic diagram of the upper wall plate in the middle section.

[0031] Figure 6 This is a bottom view structural schematic diagram of the upper wall plate in the middle section.

[0032] Figure 7 This is a bottom view structural schematic diagram of the upper wall plate in the middle section.

[0033] Figure 8 This is a bottom view structural schematic diagram of the upper wall plate in the middle section.

[0034] Figure 9 This is a structural schematic diagram of the second longitudinal beam.

[0035] Figure 10 This is a structural schematic diagram of the first short beam.

[0036] Figure 11 This is a structural schematic diagram of the second short beam.

[0037] Figure 12 This is a structural schematic diagram of the left wall plate in the middle section.

[0038] Figure 13 This is a schematic diagram of the left cabin door panel.

[0039] In the figure: 1. Upper wall plate in the middle section, 2. Left wall plate in the middle section, 3. Right wall plate in the middle section, 4. Installation beam, 5. Skin of the upper wall plate, 6. Skin of the left wall plate, 7. First connecting plate, 8. Skin of the right wall plate, 9. Second connecting plate, 10. First longitudinal beam, 11. Second longitudinal beam, 12. Third longitudinal beam, 13. First short beam, 14. Second short beam, 15. Web of the second longitudinal beam, 16. Web of the first short beam, 17. Web of the second short beam, 18. First cross beam, 19. Second cross beam, 20. Left cabin door panel, 21. Right cabin door panel, 22. Skin of the cabin door, 23. Rib of the cabin door, 24. Installation beam for the cabin door hinge, 25. Installation beam for the left wall plate hinge, 26. Tail cross beam. Detailed implementation manners

[0040] In the description of the present utility model, it should be understood that the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In the description of the present utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise specifically defined.

[0041] In the present utility model, unless otherwise clearly defined and limited, terms such as "installation", "connection", "linkage", "fixation", etc. shall be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral one; it can be a mechanical connection, an electrical connection, or communication with each other; it can be directly connected, or indirectly connected through an intermediate medium, and can be the communication inside two components or the interaction relationship between two components, unless otherwise clearly defined. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0042] As Figures 1 to 13 shown, a skin for the middle section of an aircraft engine nacelle includes an upper wall panel 1 for the middle section, a left wall panel 2 for the middle section, a right wall panel 3 for the middle section, and a mounting beam 4. The left end of the upper wall panel 1 for the middle section is detachably connected to the left wall panel 2 for the middle section, and the right end of the upper wall panel 1 for the middle section is detachably connected to the right wall panel 3 for the middle section. The mounting beam 4 is of a U-shaped structure and is arranged at the front end of the upper wall panel 1 for the middle section, the left wall panel 2 for the middle section, and the right wall panel 3 for the middle section.

[0043] The upper wall panel 1 for the middle section includes an upper wall panel skin 5.

[0044] The left wall panel 2 for the middle section includes a left wall panel skin 6 and a first connecting plate 7. The first connecting plate 7 is arranged on the lower surface of the left wall panel skin through rivets, and the right part of the first connecting plate 7 protrudes from the right end of the left wall panel skin 6 and extends below the upper wall panel skin 5, and the upper wall panel skin 5 is connected to the first connecting plate 7 through a quick-release lock.

[0045] The right wall panel 3 for the middle section includes a right wall panel skin 8 and a second connecting plate 9. The second connecting plate 9 is arranged on the lower surface of the right wall panel skin through rivets, and the left part of the second connecting plate 9 protrudes from the left end of the right wall panel skin 8 and extends below the upper wall panel skin 5, and the upper wall panel skin 5 is connected to the second connecting plate 9 through a quick-release lock.

[0046] The mounting beam 4 is located below the upper wall panel skin 5, the left wall panel skin 6, and the right wall panel skin 8. The front end of the upper wall panel skin 5 is detachably connected to the mounting beam 4 through a quick-release lock, and the front ends of the left wall panel skin 6 and the right wall panel skin 8 are connected to the mounting beam 4 through quick-release locks.

[0047] Through the above settings, a convenient detachable connection is achieved between the upper wall panel skin 5 of the upper wall panel 1 for the middle section, the left wall panel 2 for the middle section, the right wall panel 3 for the middle section, and the mounting beam 4. The disassembly and assembly are simple and fast through the setting of the quick-release lock. When the engine is overhauled, only the quick-release lock for installing the upper wall panel skin 5 needs to be disassembled to remove the upper wall panel 1 for the middle section.

[0048] In the prior art, the middle-section skin of the engine nacelle is a single-piece skin. Corresponding to the present utility model, the middle-section skin is a single-piece plate consisting of the middle-section left wall plate 2, the middle-section right wall plate 3, and the middle-section upper wall plate 1. When the engine is operating, shear forces are generated by the gas-dynamic process inside the engine and the interaction with the overall aerodynamic layout of the aircraft, and the middle-section skin of the engine nacelle acts as a shear plate. However, in the present utility model, since the middle-section upper wall plate 1 is detachably connected to the middle-section left wall plate 2 and the middle-section right wall plate 3, the original shear plate structure of the middle-section skin is damaged.

[0049] In view of this, the middle-section upper wall plate 1 further includes upper wall plate longitudinal beams and upper wall plate cross beams. There are three groups of the upper wall plate longitudinal beams, namely the first longitudinal beam 10, the second longitudinal beam 11, and the third longitudinal beam 12. The three groups of upper wall plate longitudinal beams are sequentially arranged from left to right on the lower bottom surface of the upper wall plate skin 5 and are all connected to the upper wall plate skin 5 by rivets.

[0050] The upper wall plate cross beams include a first short beam 13 and a second short beam 14. The left end of the first short beam 13 is connected to the first longitudinal beam 10, and the right end of the first short beam 13 is connected to the second longitudinal beam 11;

[0051] The left end of the second short beam 14 is connected to the second longitudinal beam 11, and the right end of the second short beam 14 is connected to the third longitudinal beam 12.

[0052] Through the arrangement of the three groups of upper wall plate longitudinal beams and the upper wall plate cross beams, the effect that the middle-section upper wall plate 1 acts as a shear plate is achieved. At the same time, through the above arrangement of the upper wall plate cross beams, the structural stiffness of the windward surface of the partial skin of the middle-section upper wall plate 1 is improved, and the technical problem of deformation of the upper wall plate skin 5 during the flight of the aircraft is avoided.

[0053] As a supplement to the above technical solution, the second longitudinal beam 11 includes a second longitudinal beam web 15. Bends are provided at both the upper end and the lower end of the second longitudinal beam web 15, so that the second longitudinal beam 11 is a U-shaped beam structure as a whole, and the notch of the second longitudinal beam 11 faces the direction of the first short beam 13.

[0054] The first short beam 13 includes a first short beam web 16. Bends are provided at both the upper end and the lower end of the first short beam web 16, so that the first short beam 13 is a Z-shaped beam structure as a whole. The bend provided at the upper end of the first short beam web 16 is used for riveting with the skin to support the skin, and the bend at the lower end of the first short beam web 16 is used to jointly increase the structural strength of the first short beam web 16 with the bend at the upper end of the first short beam web 16. The right end of the first short beam 13 is bent downward and inserted into the notch of the second longitudinal beam 11. The upper bend of the first short beam web 16 is located below the upper bend of the second longitudinal beam web 15, and the upper bend of the first short beam web 16, the upper bend of the second longitudinal beam web 15, and the upper wall plate skin 5 are riveted by rivets.

[0055] The lower bent edge of the first short beam web 16 is located above the lower bent edge of the second longitudinal beam web 15, and the lower bent edge of the first short beam web 16 and the lower bent edge of the second longitudinal beam web 15 are riveted together.

[0056] As a supplement to the above technical solution, the second short beam 14 has the same structure as the first short beam 13, including a second short beam web 17. Both the upper end and the lower end of the second short beam web 17 are provided with bent edges, making the second short beam 14 an overall Z-shaped beam structure. The upper bent edge of the second short beam web 17 is used for riveting with the skin to support the skin. The left end of the second short beam 14 abuts against the second longitudinal beam 11, and the bent edge at the lower end of the second short beam web 17 is connected to the bent edge at the lower end of the second longitudinal beam web 15 through a connecting plate. The connecting plate is of a flat plate structure. One end of the connecting plate is riveted to the bent edge at the lower end of the second short beam web 17, and the other end of the connecting plate is riveted to the bent edge at the lower end of the second longitudinal beam web 15.

[0057] In the above technical solution, the connection methods of the first short beam 13, the second short beam 14 and the second longitudinal beam 11 are different. The main reason is that the second longitudinal beam 11 is a U-shaped beam structure, so there is only one side provided with a notch. If it is necessary to have notches on both sides of the second longitudinal beam 11, the second longitudinal beam 11 needs to be set as an I-shaped beam structure. However, the I-shaped beam structure design will increase the material consumption of the second longitudinal beam 11 and at the same time increase the weight of the second longitudinal beam 11. In view of this, by connecting the second longitudinal beam 11 and the second cross beam 19 through a connecting plate, both the connection strength and the weight reduction effect of the second longitudinal beam 11 can be achieved.

[0058] As a supplement to the above technical solution, the left end of the first short beam 13 is connected to the first longitudinal beam 10 through an angle piece, and the right end of the second short beam 14 is connected to the third longitudinal beam 12 through an angle piece. The above angle piece can be an L-shaped angle piece. Taking the connection between the first short beam 13 and the first longitudinal beam 10 as an example, the first part of the angle piece is riveted to the first short beam web 16 through a rivet, and the second part of the angle piece is riveted to the first longitudinal beam 10 through a rivet. The connection method between the second short beam 14 and the third longitudinal beam 12 is the same as the connection method between the first short beam 13 and the first longitudinal beam 10.

[0059] As a preferred technical solution of the present utility model, the upper wall panel cross beam further includes a first cross beam 18 and a second cross beam 19. The first cross beam 18 and the second cross beam 19 are riveted to the lower bottom surface of the upper wall panel skin 5. The first cross beam 18 is located at the front end of the first longitudinal beam 10, the second longitudinal beam 11, and the third longitudinal beam 12 to support the front part of the upper wall panel skin 5. The second cross beam 19 is located at the rear end of the first longitudinal beam 10, the second longitudinal beam 11, and the third longitudinal beam 12 to support the rear part of the upper wall panel skin 5.

[0060] The lower end of the first cross beam 18 is provided with a bent edge, and the bent edge at the lower end of the first cross beam 18 is located below the second longitudinal beam 11. The bent edge at the lower end of the longitudinal web of the second longitudinal beam 11 is riveted to the bent edge at the lower end of the first cross beam 18.

[0061] The lower end of the second cross beam 19 is provided with a bent edge, and the bent edge at the lower end of the second cross beam 19 is located below the second longitudinal beam 11. The bent edge at the lower end of the longitudinal web of the second longitudinal beam 11 is riveted to the bent edge at the lower end of the second cross beam 19.

[0062] As a supplement to the above technical solution, the upper wall panel longitudinal beam and the upper wall panel cross beam are both provided with weight reduction holes to reduce the weight of the upper wall panel longitudinal beam and the upper wall panel cross beam.

[0063] As a preferred technical solution of the present invention, it further includes a left cabin door panel 20, a right cabin door panel 21, a left cabin door hinge, and a right cabin door hinge. The upper end of the left cabin door panel 20 is connected to the middle left wall panel 2 through the left cabin door hinge, and the upper end of the right cabin door panel 21 is connected to the middle right wall panel 3 through the right cabin door hinge.

[0064] The left cabin door panel 20 and the right cabin door panel 21 have the same structure. The left cabin door panel 20 includes a cabin door skin 22, cabin door rib plates 23, and a cabin door hinge mounting beam 24. The cabin door rib plates 23 are arranged inside the cabin door skin 22 and are connected to the cabin door skin 22 by rivets for supporting the cabin door skin 22.

[0065] The cabin door hinge mounting beam 24 is arranged at the upper part of the left cabin door skin 22.

[0066] The cabin door hinge mounting beam 24 is riveted to the inner surface of the left cabin door skin 22 and is located at the upper end of the left cabin door skin 22 to provide structural strength for the cabin door hinge mounting beam 24.

[0067] The middle left wall panel 2 further includes a left wall panel hinge mounting beam 25. The left wall panel hinge mounting beam 25 is riveted to the inner surface of the left wall panel skin 6 and is located at the lower end of the left wall panel skin 6. The left wall panel hinge mounting beam 25 is provided for connecting with the left cabin door panel 20 and at the same time increasing the structural strength of the left wall panel skin 6.

[0068] The left cabin door hinge includes a first leaf, a second leaf, and a hinge shaft. The first leaf and the second leaf are connected by the hinge shaft. The first leaf is connected to the left wall panel hinge mounting beam 25, and the second leaf is connected to the cabin door hinge mounting beam 24. Through the above structure, the flipping function of the left cabin door panel 20 relative to the middle left wall panel 2 is realized.

[0069] Correspondingly, the middle right wall panel 3 further includes a right wall panel hinge mounting beam 4. The right cabin door panel is connected to the middle right wall panel 3 through the right cabin door hinge, and the connection method is the same as the connection method between the left cabin door panel and the middle right wall panel 3.

[0070] As a supplement to the above technical solution, a weight-reducing hole is provided on the hatch rib 23 for reducing the weight of the hatch rib 23.

[0071] As a supplement to the above technical solution, a tail cross beam 26 is further included. The tail cross beam 26 is arranged at the rear ends of the upper middle wall panel 1, the left middle wall panel 2, and the right middle wall panel 3. The rear end of the upper wall panel skin 5 is connected to the tail cross beam 26 through a quick-release lock, and the rear ends of the left wall panel skin 6 and the right wall panel skin 8 are connected to the tail cross beam 26 through quick-release locks.

[0072] The above is only a preferred specific implementation manner of the present utility model, but the protection scope of the present utility model is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present utility model, according to the technical solution and the inventive concept of the present utility model, makes equivalent substitutions or changes, and should be covered by the protection scope of the present utility model.

Claims

1. An intermediate section skin of an aircraft engine nacelle, characterized in that, It includes a middle-section upper wall panel (1), a middle-section left wall panel (2), a middle-section right wall panel (3), and a mounting beam (4). The mounting beam (4) is of a U-shaped structure and is arranged at the front ends of the middle-section upper wall panel (1), the middle-section left wall panel (2), and the middle-section right wall panel (3). The middle-section upper wall panel (1) includes an upper wall panel skin (5). The middle-section left wall panel (2) includes a left wall panel skin (6) and a first connecting plate (7). The first connecting plate (7) is arranged on the lower surface of the left wall panel skin (6) by rivets, and the right part of the first connecting plate (7) protrudes from the right end of the left wall panel skin (6) and extends below the upper wall panel skin (5), and is connected to the upper wall panel skin (5) by a quick-release lock. The middle-section right wall panel (3) includes a right wall panel skin (8) and a second connecting plate (9). The second connecting plate (9) is arranged on the lower surface of the right wall panel skin (8) by rivets, and the left part of the second connecting plate (9) protrudes from the left end of the right wall panel skin (8) and extends below the upper wall panel skin (5), and is connected to the upper wall panel skin (5) by a quick-release lock. The mounting beam (4) is located below the upper wall panel skin (5), the left wall panel skin (6), and the right wall panel skin (8). The front ends of the upper wall panel skin (5), the left wall panel skin (6), and the right wall panel skin (8) are all connected to the mounting beam (4) by quick-release locks.

2. The mid-section skin of an aircraft engine nacelle according to claim 1, wherein, The middle-section upper wall panel (1) further includes upper wall panel longitudinal beams and upper wall panel cross beams. There are three groups of upper wall panel longitudinal beams, namely the first longitudinal beam (10), the second longitudinal beam (11), and the third longitudinal beam (12). The three groups of upper wall panel longitudinal beams are arranged in sequence from left to right on the lower bottom surface of the upper wall panel skin (5), and are all connected to the upper wall panel skin (5) by rivets. The upper wall panel cross beams include a first short beam (13) and a second short beam (14). The left end of the first short beam (13) is connected to the first longitudinal beam (10), and the right end of the first short beam (13) is connected to the second longitudinal beam (11). The left end of the second short beam (14) is connected to the second longitudinal beam (11), and the right end of the second short beam (14) is connected to the third longitudinal beam (12).

3. The mid-section skin of an aircraft engine nacelle according to claim 2, characterized in that, The second longitudinal beam (11) includes a second longitudinal beam web (15). Bends are provided at both the upper end and the lower end of the second longitudinal beam web (15), so that the second longitudinal beam (11) is of an overall structure with a notch and a "U"-shaped cross-section, and the notch of the second longitudinal beam (11) faces the direction of the first short beam (13). The first short beam (13) includes a first short beam web (16). Bends are provided at both the upper end and the lower end of the first short beam web (16), so that the first short beam (13) has a "Z"-shaped cross-section. The bend provided at the upper end of the first short beam web (16) is riveted to the skin. The right end of the first short beam (13) is located within the notch of the second longitudinal beam (11). The bend at the upper end of the first short beam web (16) is located below the bend at the upper end of the second longitudinal beam web (15). The bend at the upper end of the first short beam web (16), the bend at the upper end of the second longitudinal beam web (15), and the upper wall panel skin (5) are riveted together. The lower bent edge of the first short beam web (16) is located above the lower bent edge of the second longitudinal beam web (15), and the lower bent edges of the first short beam web (16) and the second longitudinal beam web (15) are riveted together.

4. The middle skin of the nacelle of an aircraft engine according to claim 3, characterized in that The second short beam (14) includes a second short beam web (17). Bent edges are provided at both the upper and lower ends of the second short beam web (17). The upper bent edge of the second short beam web (17) is riveted to the upper wall panel skin (5), and the bent edge at the lower end of the second short beam web (17) is connected to the bent edge at the lower end of the second longitudinal beam web (15) through a connecting plate.

5. The mid-section skin of an aircraft engine nacelle according to claim 2, characterized in that, The upper wall panel cross beam further includes a first cross beam (18) and a second cross beam (19). The first cross beam (18) and the second cross beam (19) are riveted to the lower bottom surface of the upper wall panel skin (5). The first cross beam (18) is located at the front end of the first longitudinal beam (10), the second longitudinal beam (11), and the third longitudinal beam (12). The second cross beam (19) is located at the rear end of the first longitudinal beam (10), the second longitudinal beam (11), and the third longitudinal beam (12). A bent edge is provided at the lower end of the first cross beam (18). The bent edge at the lower end of the first cross beam (18) is located below the second longitudinal beam (11), and the bent edge at the lower end of the second longitudinal beam web (15) is riveted to the bent edge at the lower end of the first cross beam (18). A bent edge is provided at the lower end of the second cross beam (19). The bent edge at the lower end of the second cross beam (19) is located below the second longitudinal beam (11), and the bent edge at the lower end of the second longitudinal beam web (15) is riveted to the bent edge at the lower end of the second cross beam (19).

6. The mid-section skin of an aircraft engine nacelle according to claim 1, characterized in that, The left end of the first short beam (13) is connected to the first longitudinal beam (10) through an angle piece, and the right end of the second short beam (14) is connected to the third longitudinal beam (12) through an angle piece.

7. The mid-section skin of an aircraft engine nacelle according to claim 1, characterized in that, It further includes a left cabin door panel (20), a right cabin door panel (21), a left cabin door hinge, and a right cabin door hinge. The left cabin door panel (20) and the right cabin door panel (21) have the same structure. The left cabin door panel (20) includes a cabin door skin (22), cabin door rib plates (23), and a cabin door hinge mounting beam (24). The cabin door rib plates (23) are arranged on the inner side of the cabin door skin (22) and are connected to the cabin door skin (22) through rivets. The cabin door hinge mounting beam (24) is riveted to the inner surface of the left cabin door skin (22) and is located at the upper end of the left cabin door skin (22). The upper ends of the cabin door rib plates (23) are riveted to the cabin door hinge mounting beam (24). The middle section left wall panel (2) further includes a left wall panel hinge mounting beam (25). The left wall panel hinge mounting beam (25) is riveted to the inner surface of the left wall panel skin (6) and is located at the lower end of the left wall panel skin (6). The cabin door hinge mounting beam (24) and the left wall panel hinge mounting beam (25) are connected through a left cabin door hinge. The middle section right wall panel (3) further includes a right wall panel hinge mounting beam (4). The right cabin door panel (21) is connected to the middle section right wall panel (3) through a right cabin door hinge.

8. The middle section skin of an aircraft engine nacelle according to claim 1, characterized in that, It further includes a tail crossbeam (26), and the tail crossbeam (26) is arranged at the rear ends of the middle-section upper wall panel (1), the middle-section left wall panel (2), and the middle-section right wall panel (3). The rear ends of the upper wall panel skin (5), the left wall panel skin (6), and the right wall panel skin (8) are all connected to the tail crossbeam (26) through quick-release locks.

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