Rocket engine assembly tool and assembly method

Abstract

The invention relates to the technical field of rocket final assembly, and discloses a rocket engine assembly tool and method.The rocket engine assembly tool comprises a rolling stand vehicle and a rolling supporting body, the rolling supporting body is provided with a central axis and arranged on the rolling stand vehicle in a rolling mode along the central axis, and the central axis is parallel to the ground; the rocket tail section is detachably fixed to the rolling supporting body, the axis of the rocket tail section coincides with the central axis, the multiple engine installation positions on the rocket tail section comprise the central engine installation position and the multiple peripheral engine installation positions, and the central engine installation position is used for assembling a central engine and rotates along with rotation of the rolling supporting body. And the position of the center engine installation position is not changed, and the multiple peripheral engine installation positions sequentially reach the preset assembly positions so that all the peripheral engines can be in butt joint assembly with the rocket tail section at the preset assembly positions. The engine assembly efficiency is high, and the assembly precision is high.

Description

Technical Field

[0001] The present invention relates to the technical field of rocket assembly, and in particular to a rocket engine assembly tool and an assembly method. Background Art

[0002] With the rapid development of commercial aerospace, the pursuit of high thrust in the form of recyclable liquid rockets has gradually shifted from the original development of high-thrust engines and increased boost to the parallel connection of multiple engines, which improves the carrying capacity while reducing the difficulty of single engine development and production processing. It has the advantages of high thrust, high reliability, low launch cost, and high flexibility. There are many problems with multiple engines in parallel, among which the difficulty of assembly will be greatly increased, the layout between engines will be closer, and the number of electrical cables and pipelines will increase exponentially, which greatly increases the difficulty of hoisting, assembly and testing.

[0003] Therefore, there is an urgent need for a rocket engine assembly tool and assembly method to solve the above problems. Summary of the invention

[0004] Based on the above, the purpose of the present invention is to provide a rocket engine assembly tool and assembly method, which has high engine assembly efficiency and high assembly accuracy.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] A rocket engine assembly tool, used for assisting multiple engines to be assembled one by one to multiple engine installation positions on a rocket tail section, characterized in that the rocket engine assembly tool comprises:

[0007] Rolling frame car;

[0008] A rolling support body has a central axis, and the rolling support body is rolled along the central axis and placed on the rolling frame vehicle, and the central axis is parallel to the ground. The rocket tail section is detachably fixed to the rolling support body, and the axis of the rocket tail section coincides with the central axis. The multiple engine mounting positions on the rocket tail section include a central engine mounting position and multiple peripheral engine mounting positions, and the central engine mounting position is used to assemble a central engine. As the rolling support body rotates, the position of the central engine mounting position remains unchanged, and the multiple peripheral engine mounting positions reach preset assembly positions in sequence, so that each peripheral engine can be docked and assembled with the rocket tail section at the preset assembly position.

[0009] As a preferred solution for a rocket engine assembly tool, the rolling support body includes a front frame and a rear frame spaced apart along the central axis, the front frame and the rear frame are both annular structures, a plurality of support rods are circumferentially connected between the front frame and the rear frame, the front frame and the rear frame are rolled on the rolling frame, and the rocket tail section is detachably fixed to the rear frame.

[0010] As a preferred solution for a rocket engine assembly tool, a plurality of first connecting members are circumferentially spaced apart on the rear frame, and a plurality of second connecting members distributed circumferentially are provided on the rocket tail section. The plurality of second connecting members are detachably connected to the plurality of first connecting members in a one-to-one correspondence.

[0011] As a preferred solution for a rocket engine assembly tool, an auxiliary positioning component is provided in the front frame, and the auxiliary positioning component includes a plurality of auxiliary positioning plates, and the plurality of auxiliary positioning plates are directly opposite to the plurality of engine mounting positions.

[0012] As a preferred solution for a rocket engine assembly tool, a first connecting rod is connected between every two of the auxiliary positioning plates, and a second connecting rod is connected between at least one of the auxiliary positioning plates and the front frame.

[0013] As a preferred solution for a rocket engine assembly tool, the rolling frame vehicle includes at least two arc-shaped frames spaced apart along a first direction, each of the arc-shaped frames is mounted with at least two rollers, each of the rollers is rotatably arranged on the arc-shaped frame along the axis of the roller, the axis of the roller is parallel to the central axis, and the rolling support body is supported on a plurality of the rollers.

[0014] As a preferred solution for a rocket engine assembly tool, the rolling frame also includes a plurality of driving sources, and the plurality of driving sources drive and connect the plurality of rollers in a one-to-one correspondence.

[0015] As a preferred solution for a rocket engine assembly tool, the rolling frame vehicle also includes a base frame, each of the arc-shaped frame bodies is arranged on the base frame, and a plurality of running wheels are arranged at the bottom of the base frame.

[0016] As a preferred solution for a rocket engine assembly tool, each of the arc-shaped frames is positionally adjustable on the base frame along a second direction, and the second direction is perpendicular to the central axis and parallel to the ground.

[0017] A rocket engine assembly method, based on the rocket engine assembly tooling described in any of the above technical solutions, the method comprises the following steps:

[0018] S1: fixing the rocket tail section on the rolling support body;

[0019] S2: Lay the central engine flat and hoist it to the central engine installation position of the rocket tail section, and then connect and fix the central engine to the rocket tail section;

[0020] S3: rotating the rolling support body so that one of the peripheral engine mounting positions on the rocket tail section is located at the preset assembly position;

[0021] S4: hoisting one of the peripheral engines to the peripheral engine installation position aligned with the preset assembly position, and connecting and fixing the peripheral engine to the rocket tail section;

[0022] S5: Repeat the above steps S3 and S4 until all engines are assembled.

[0023] A rocket engine assembly method,

[0024] The beneficial effects of the present invention are:

[0025] The present invention provides a rocket engine assembly tool, which enables a rocket tail section fixedly connected to the rolling support body to stably and reliably rotate around its own axis by rollingly supporting a rolling support body on a rolling frame, so that a plurality of peripheral engine mounting positions on the rocket tail end can be rotated to fixed preset assembly positions in sequence, which facilitates the assembly of the plurality of peripheral engines with the rocket tail end after being hoisted to fixed positions in sequence, thereby improving assembly accuracy, and effectively overcoming assembly difficulties caused by space limitations during assembly, which is beneficial to improving assembly efficiency and maintainability; at the same time, when assembling the engine, the power pipeline can be assembled at the same time, and the rotatable adjustment of the rocket tail section is beneficial to reducing the difficulty of assembling the power pipeline and improving assembly efficiency.

[0026] The present invention also provides a rocket engine assembly method, which is simple and easy to implement, reduces the difficulty of engine assembly, and is beneficial to improving assembly efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments of the present invention. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on the contents of the embodiments of the present invention and these drawings without paying any creative work.

[0028] Figure 1 It is a structural schematic diagram of a rocket engine assembly tool assisting engine assembly at one viewing angle provided by an embodiment of the present invention;

[0029] Figure 2is a schematic structural diagram of a rocket engine assembly tool assisting engine assembly from another perspective provided by an embodiment of the present invention;

[0030] Figure 3 is a schematic structural diagram of a rocket engine assembly tool provided by an embodiment of the present invention;

[0031] Figure 4 is a schematic structural diagram of a rolling frame vehicle provided by an embodiment of the present invention at a viewing angle;

[0032] Figure 5 is a schematic structural diagram of a rolling frame vehicle provided by an embodiment of the present invention from another perspective;

[0033] Figure 6 It is a flow chart of a rocket engine assembly method provided by an embodiment of the present invention.

[0034] In the figure:

[0035] 1. Rolling frame; 11. Arc frame; 12. Roller; 13. Driving source; 14. Base frame; 15. Traveling wheel; 16. Screw rod; 17. Hand wheel; 2. Rolling support body; 21. Front frame; 22. Rear frame; 23. Support rod; 24. First connecting member; 25. Second connecting member; 26. Auxiliary positioning plate; 27. First connecting rod; 28. Second connecting rod;

[0036] 100. Rocket tail section; 200. Central engine; 300. Peripheral engine. DETAILED DESCRIPTION

[0037] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It is to be understood that the specific embodiments described herein are only used to explain the present invention, rather than to limit the present invention. It should also be noted that, for ease of description, only parts related to the present invention, rather than all structures, are shown in the accompanying drawings.

[0038] In the description of the present invention, unless otherwise clearly specified and limited, the terms "connected", "connected", and "fixed" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0039] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0040] In the description of the present embodiment, the terms "upper", "lower", "left", "right" and other directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings, and are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific direction, be constructed and operated in a specific direction, and therefore cannot be understood as a limitation of the present invention. In the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more. In addition, the terms "first" and "second" are only used to distinguish in the description and have no special meaning.

[0041] like Figures 1 to 5As shown, this embodiment provides a rocket engine assembly tool, which is used to assist multiple engines to be assembled one by one to multiple engine installation positions on the rocket tail section 100, wherein the rocket tail end has a central engine installation position and multiple peripheral engine installation positions arranged around the periphery of the central engine installation position at intervals, the central engine 200 is used for the assembly of the central engine 200, and the peripheral engine installation position is used for the assembly of the peripheral engine 300. Specifically, the rocket engine assembly tool includes a rolling frame 1 and a rolling support body 2, the rolling support body 2 has a central axis, the rolling support body 2 is rolled along the central axis and placed on the rolling frame 1, the central axis is parallel to the ground, the rocket tail section 100 is detachably fixed to the rolling support body 2, the axis of the rocket tail section 100 coincides with the central axis, with the rotation of the rolling support body 2, the position of the central engine installation position remains unchanged, and the multiple peripheral engine installation positions reach the preset assembly position in sequence, so that each peripheral engine 300 can be docked and assembled with the rocket tail section 100 at the preset assembly position. Compared with the prior art of vertically hoisting engines, each engine has a different hoisting position during assembly, which not only affects the alignment accuracy, but also easily causes interference between the assembled engine and the engine to be assembled. The rocket engine assembly tooling provided in this embodiment rolls the rolling support body 2 on the rolling frame 1, so that the rocket tail section 100 fixedly connected to the rolling support body 2 can stably and reliably rotate around its own axis, so that the multiple peripheral engine installation positions on the tail end of the rocket can be rotated to the fixed preset assembly position in turn, which is convenient for assembling the multiple peripheral engines 300 with the rocket tail end after being hoisted to the fixed position in turn, improving the assembly accuracy, and effectively overcoming the assembly difficulties caused by space limitations during assembly, which is conducive to improving assembly efficiency and maintainability. At the same time, when assembling the engine, the power pipeline can be assembled at the same time, and the rotatable adjustment of the rocket tail section 100 is conducive to reducing the difficulty of assembling the power pipeline and improving assembly efficiency. Among them, the preset assembly position is preferably the highest point that the peripheral engine mounting position can reach during the entire rotation process, that is, each peripheral engine 300 is assembled at a fixed highest point, so that each peripheral engine 300 has more sufficient assembly space during assembly, reducing the difficulty of assembly and improving assembly efficiency.

[0042] More specifically, if Figures 1 to 3As shown, the rolling support body 2 includes a front frame 21 and a rear frame 22 spaced apart along the central axis, and the front frame 21 and the rear frame 22 are both annular structures. A plurality of support rods 23 are connected between the front frame 21 and the rear frame 22 along the circumferential direction. The front frame 21 and the rear frame 22 are rolled on the rolling frame 1, and the rocket tail section 100 is detachably fixed to the rear frame 22. The annular frame structure of the front frame 21 and the rear frame 22, while realizing stable rolling support on the rolling frame 1 so as to drive the rocket tail section 100 to roll stably, facilitates the engine to be hoisted between the front frame 21 and the rear frame 22 to be aligned and assembled with the rocket tail section 100, and also facilitates the central engine 200 to be hoisted and inserted between the front frame 21 and the rear frame 22. Among them, the number of support rods 23 is, for example, three, four, five, etc., which is specifically set according to actual needs to ensure the structural stability and strength of the rolling support body 2.

[0043] In this embodiment, a plurality of first connecting members 24 are arranged at intervals along the circumferential direction on the rear frame 22, and a plurality of second connecting members 25 are arranged along the circumferential direction on the rocket tail section 100, and the plurality of second connecting members 25 are detachably connected to the plurality of first connecting members 24 in a one-to-one correspondence. Before assembly, the rocket tail section 100 is placed in the rear frame 22, and the plurality of second connecting members 25 are made to correspond to the plurality of first connecting members 24 in a one-to-one correspondence, and then the first connecting members 24 and the second connecting members 25 are connected one by one to realize the fixed connection between the rocket tail section 100 and the rear frame 22, that is, the rocket tail section 100 rolls with the rolling support body 2; after the engine assembly is completed, the connection between the first connecting member 24 and the second connecting member 25 is removed, and the rocket tail section 100 can be removed from the rear frame 22.

[0044] Preferably, the rear frame 22 includes a plurality of arc segments, which are detachably connected to each other, and the plurality of arc segments are connected to form a ring-shaped rear frame 22. The detachable connection of the plurality of arc segments facilitates smooth separation from the rear frame 22 after the engine is assembled on the rocket tail section 100. For example, the rear frame 22 is composed of two semicircular segments, which are detachably connected to each other. After the engine is assembled, the connection between the first connecting member 24 and the second connecting member 25 and the connection between the two semicircular segments are removed, and the rocket tail section 100 can be smoothly separated from the rear frame 22.

[0045] Exemplarily, the first connecting member 24 is a connecting seat, and the second connecting member 25 is a connecting ear. The connecting seat and the connecting ear are fixedly connected by bolts, which is convenient for disassembly and assembly, and has high structural stability. Of course, in other embodiments, the first connecting member 24 and the second connecting member 25 can also be other, for example, the first connecting member 24 and the second connecting member 25 are both threaded holes.

[0046] In order to further improve the alignment accuracy of the engine, an auxiliary positioning member is provided in the front frame 21, and the auxiliary positioning member includes a plurality of auxiliary positioning plates 26, and the plurality of auxiliary positioning plates 26 are aligned with the plurality of engine mounting positions one by one. When assembling the engine, the engine is hoisted between the front frame 21 and the rear frame 22 until both ends of the engine are aligned with the preset assembly position and the auxiliary positioning plates 26 that are aligned with the preset assembly position, respectively, so that the spatial position of the engine is more accurate and reliable, which is conducive to improving the assembly accuracy.

[0047] Preferably, a first connecting rod 27 is connected between every two auxiliary positioning plates 26, and a second connecting rod 28 is connected between at least one auxiliary positioning plate 26 and the front frame 21. The first connecting rod 27 and the second connecting rod 28 enable the multiple auxiliary positioning plates 26 to be stably connected to the front frame 21. For example, the multiple auxiliary positioning plates 26 include a central auxiliary positioning plate 26 and multiple peripheral auxiliary positioning plates 26, the central auxiliary positioning plate 26 corresponds to the central engine installation position, and the multiple peripheral auxiliary positioning plates 26 correspond to multiple peripheral engine installation positions. A second connecting rod 28 is connected between each peripheral auxiliary positioning plate 26 and the front frame 21 to ensure the structural stability of the auxiliary positioning components.

[0048] Furthermore, if Figure 4 and Figure 5 As shown, the rolling frame vehicle 1 includes at least two arc-shaped frames 11 spaced apart along a first direction, each arc-shaped frame 11 is mounted with at least two rollers 12, each roller 12 is rotatably arranged on the arc-shaped frame 11 along the axis of the roller 12, the axis of the roller 12 is parallel to the central axis, and the rolling support body 2 is supported on a plurality of rollers 12. The curvature of the inner edge of the arc-shaped frame 11 is adapted to the curvature of the front frame 21 and the rear frame 22. The front frame 21 and the rear frame 22 supported thereon are driven to rotate by the rolling of the rollers 12, so the structure is simple and the cost is low.

[0049] In this embodiment, the rolling frame also includes a plurality of driving sources 13, and the plurality of driving sources 13 drive and connect the plurality of rollers 12 one by one, that is, each driving source 13 drives one roller 12 to rotate. For example, the driving source 13 is a motor, which is installed on the side of the arc-shaped frame 11 and drives and connects the rollers 12 to achieve automatic rolling, saving time and effort. Preferably, the rocket engine assembly tool also includes a controller, which is electrically connected to the plurality of driving sources 13, and is used to control the simultaneous start and stop of the plurality of driving sources 13, to ensure the rotation synchronization of the plurality of rollers 12, that is, to ensure the rolling stability of the rolling support 2.

[0050] Specifically, the rolling frame vehicle 1 further includes a base frame 14, each arc-shaped frame body 11 is arranged on the base frame 14, and a plurality of running wheels 15 are arranged at the bottom of the base frame 14. The arrangement of the running wheels 15 facilitates the movement of the rocket engine assembly tool, that is, facilitates the transportation of the rocket engine assembly tool or adjusts the position of the rocket engine assembly tool.

[0051] Optionally, each arc-shaped frame 11 is positionally adjustable on the base frame 14 along a second direction, and the second direction is perpendicular to the central axis and parallel to the ground, thereby improving the flexibility of use of the rocket engine assembly tool.

[0052] Exemplarily, the base frame 14 includes two support base plates connected at intervals, each support base plate is provided with two first connection plates, and each arc-shaped frame body 11 is provided with a second connection plate at both ends, and the two second connection plates correspond to the two first connection plates one by one and are connected by a screw rod 16. The length of the two screw rods 16 extends along the second direction, and the position of the arc-shaped frame body 11 on the support base plate can be adjusted by rotating the screw rod 16. Preferably, a hand wheel 17 is provided at the end of the screw rod 16 to facilitate the application of force to rotate the screw rod 16.

[0053] like Figures 1 to 6 As shown, this embodiment also provides a rocket engine assembly method. Based on the above rocket engine assembly tool, the method includes the following steps:

[0054] S1: Fixing the rocket tail section 100 on the rolling support 2;

[0055] At this time, the axis of the rocket tail section 100 is parallel to the ground and coincides with the central axis of the rolling support body 2, that is, when the rolling support body 2 rotates, it drives the rocket tail section 100 to rotate along its own axis, so that each peripheral engine mounting position on the rocket tail section 100 can be rotated to the highest point.

[0056] S2: Lay the central engine 200 horizontally and hoist it to the central engine installation position of the rocket tail section 100, and then connect and fix the central engine 200 to the rocket tail section 100;

[0057] S3: rotating the rolling support body 2 so that a peripheral engine mounting position on the rocket tail section 100 is located at a preset assembly position;

[0058] Preferably, the preset assembly position is the highest position that can be reached during the rotation of the peripheral engine mounting position, which facilitates the assembly operation.

[0059] S4: hoisting a peripheral engine 300 to a peripheral engine installation position aligned with a preset assembly position, and connecting and fixing the peripheral engine 300 to the rocket tail section 100;

[0060] Among them, when assembling each peripheral engine 300, the power pipeline assembly can be carried out at the same time, saving assembly time, and the rotating setting of the rocket tail section 100 is convenient for adjusting the position when assembling the power pipeline, reducing the difficulty of assembly.

[0061] S5: Repeat the above steps S3 and S4 until all engines are assembled.

[0062] To assemble multiple peripheral engines 300, it is only necessary to hoist each peripheral engine 300 to the same position, which can save the space occupied by hoisting, and assemble them horizontally at the top, so that the effective space during assembly is larger, the operation difficulty is reduced, and the assembly efficiency is improved.

[0063] Note that the above are only preferred embodiments of the present invention and the technical principles used. Those skilled in the art will understand that the present invention is not limited to the specific embodiments described herein, and that various obvious changes, readjustments and substitutions can be made by those skilled in the art without departing from the scope of protection of the present invention. Therefore, although the present invention has been described in more detail through the above embodiments, the present invention is not limited to the above embodiments, and may include more other equivalent embodiments without departing from the concept of the present invention, and the scope of the present invention is determined by the scope of the appended claims.

Claims

1. A rocket engine assembly tool, used to assist in assembling multiple engines one by one to multiple engine installation positions on the rocket tail section, characterized in that: The rocket engine assembly tool comprises: Rolling frame car; A rolling support body has a central axis, and the rolling support body is rolled along the central axis and placed on the rolling frame vehicle, and the central axis is parallel to the ground. The rocket tail section is detachably fixed to the rolling support body, and the axis of the rocket tail section coincides with the central axis. The multiple engine mounting positions on the rocket tail section include a central engine mounting position and multiple peripheral engine mounting positions, and the central engine mounting position is used to assemble a central engine. As the rolling support body rotates, the position of the central engine mounting position remains unchanged, and the multiple peripheral engine mounting positions reach preset assembly positions in sequence, so that each peripheral engine can be docked and assembled with the rocket tail section at the preset assembly position.

2. The rocket engine assembly tool according to claim 1, characterized in that: The rolling support body includes a front frame and a rear frame spaced apart along the central axis, the front frame and the rear frame are both annular structures, a plurality of support rods are circumferentially connected between the front frame and the rear frame, the front frame and the rear frame are rolled on the rolling frame, and the rocket tail section is detachably fixed to the rear frame.

3. The rocket engine assembly tool according to claim 2, characterized in that: A plurality of first connecting members are arranged at intervals along the circumferential direction on the rear frame, and a plurality of second connecting members distributed along the circumferential direction are provided on the tail section of the rocket. The plurality of second connecting members are detachably connected to the plurality of first connecting members in a one-to-one correspondence.

4. The rocket engine assembly tool according to claim 2, characterized in that: The front frame is provided with an auxiliary positioning component, which includes a plurality of auxiliary positioning plates, and the plurality of auxiliary positioning plates are directly opposite to the plurality of engine mounting positions one by one.

5. The rocket engine assembly tool according to claim 4, characterized in that: A first connecting rod is connected between every two of the auxiliary positioning plates, and a second connecting rod is connected between at least one of the auxiliary positioning plates and the front frame.

6. The rocket engine assembly tool according to claim 1, characterized in that: The rolling frame vehicle includes at least two arc-shaped frames spaced apart along a first direction, each of the arc-shaped frames is mounted with at least two rollers, each of the rollers is rotatably arranged on the arc-shaped frame along the axis of the roller, the axis of the roller is parallel to the central axis, and the rolling support body is supported on a plurality of the rollers.

7. The rocket engine assembly tool according to claim 6, characterized in that: The rolling frame also includes a plurality of driving sources, and the plurality of driving sources are connected to the plurality of rollers in a one-to-one driving manner.

8. The rocket engine assembly tool according to claim 6, characterized in that: The rolling frame vehicle also includes a base frame, each of the arc-shaped frame bodies is arranged on the base frame, and a plurality of walking wheels are arranged at the bottom of the base frame.

9. The rocket engine assembly tool according to claim 8, characterized in that: Each arc-shaped frame body is positionally adjustable on the base frame along a second direction, wherein the second direction is perpendicular to the central axis and parallel to the ground.

10. A rocket engine assembly method, based on the rocket engine assembly tool according to any one of claims 1 to 9, characterized in that: The method comprises the following steps: S1: fixing the rocket tail section on the rolling support body; S2: Lay the central engine flat and hoist it to the central engine installation position of the rocket tail section, and then connect and fix the central engine to the rocket tail section; S3: rotating the rolling support body so that one of the peripheral engine mounting positions on the rocket tail section is located at the preset assembly position; S4: hoisting one of the peripheral engines to the peripheral engine installation position aligned with the preset assembly position, and connecting and fixing the peripheral engine to the rocket tail section; S5: Repeat the above steps S3 and S4 until all engines are assembled.

Images