Projectile small angle water entry test launcher and method

Abstract

The present application relates to a kind of small-angle water entry test launching device and method of projectile, including support plate, support plate is fixedly installed with launch tube, launch tube is used to launch projectile;Support plate is fixedly installed in test pool one side;Arc guide rail, arc guide rail is located on support plate, support plate and arc guide rail sliding connection;Locking structure, locking structure is used to detachably fixedly connected with support plate and support plate;Wherein, the sliding-bore axis direction of launch tube always passes through the track center of arc guide rail, the water entry point of projectile is track center, the length of arc guide rail and the adjustment range of water entry angle of projectile are adapted, to reduce the requirement of water area range to water entry test, improve test efficiency under the condition of low cost.

Description

Technical Field

[0001] This invention relates to the field of testing and experimental technology, and in particular to a launching device and method for a small-angle water entry test of a projectile. Background Technology

[0002] Supercavitating projectiles launched from above the water surface can significantly reduce velocity decay upon entry, thus maintaining their effective destructive power. However, as the projectile passes through the water surface from the air, it undergoes a rapid change in environmental density, involving complex gas-liquid multiphase flow and fluid-structure interaction issues. Especially when the projectile's entry angle is small, ricocheting is prone to occur. Therefore, achieving a stable water-entry cavitation bubble and a stable trajectory across the free surface requires specialized projectile design and trajectory planning.

[0003] In past research, theoretical analysis and numerical simulation have been the main research methods. In order to obtain the water cavitation, water entry trajectory stability and underwater target depth residual velocity of the projectile after entering the water at different velocities within a small angle range through experiments, it is necessary to design a projectile water entry launching device with an adjustable angle within a small angle range for experimental research.

[0004] Existing test launchers often adjust the launch angle by rotating the launch barrel at a specific position. This method results in significant variations in the water entry point of projectiles launched at small angles. In laboratory settings with limited water area, it is difficult to provide a wide water area for small-angle water entry tests. Furthermore, the limited measurement range of the measuring equipment makes it difficult to fully cover the changing water entry point. To reduce the investment cost of the measuring equipment, the measurement position of the measuring equipment needs to be adjusted according to the changes in the projectile's water entry position, which greatly increases the time required for the test. Summary of the Invention

[0005] In response to the shortcomings of the existing production technology, the applicant provides a launching device and method for a small-angle water entry test of a projectile, thereby reducing the requirements for the water area range of the water entry test and improving the test efficiency under low cost conditions.

[0006] The technical solution adopted in this invention is as follows:

[0007] A projectile launcher for a small-angle water entry test, comprising:

[0008] A tray, on which a launching tube is fixedly mounted, the launching tube being used to launch the projectile;

[0009] A support plate, which is fixedly installed on one side of the test water tank;

[0010] An arc-shaped guide rail is located on the support plate, and the support plate is slidably connected to the arc-shaped guide rail;

[0011] A locking structure is provided for detachably and securely connecting the tray to the support plate.

[0012] The smoothbore axis of the launch tube always passes through the center of the trajectory of the arc-shaped guide rail, the water entry point of the projectile is the center of the trajectory, and the length of the arc-shaped guide rail is adapted to the adjustment range of the water entry angle of the projectile.

[0013] As a further improvement to the above technical solution:

[0014] It also includes an auxiliary adjustment structure, which includes a pull rod and a tension assembly mounted on the upper part of the support plate. One end of the pull rod is hinged to the support plate, and the other end of the pull rod is connected to the tension assembly. Changing the length of the pull rod below the tension assembly adjusts the size of the water entry angle.

[0015] The tension assembly includes a lifting ring with one end rotatably connected to the support plate, a pull rod slidably connected to a through hole on the lifting ring, the pull rod being a screw rod, and a first nut being screwed onto the pull rod. The first nut cooperates with the lifting ring to limit the length of the pull rod below the tension assembly.

[0016] It also includes a second nut that is screwed to the pull rod. The second nut and the first nut are located on both sides of the lifting ring, and the pull rod is fixedly connected to the lifting ring when the first nut and the second nut are in contact with the lifting ring at the same time.

[0017] The arc-shaped guide rail includes an arc-shaped through hole on the support plate, and two guide posts corresponding to an arc-shaped through hole are spaced apart on the support plate, with each guide post slidably connected to the arc-shaped through hole.

[0018] One end of the guide post is a threaded section, and the other end of the guide post is a limiting head. The locking structure includes a third nut that is screwed to the threaded section. When the third nut is tightened, the support plate is fixedly connected to the support plate.

[0019] The guide post is a standard bolt.

[0020] The number of arc-shaped guide rails is two, and they are arranged concentrically.

[0021] The tray is equipped with a clamp, which is used to detachably and securely connect the launch tube to the tray.

[0022] A method for testing projectiles entering water at a small angle includes the following steps:

[0023] Determine the location of the projectile's entry point into the water;

[0024] Install the above-mentioned projectile small-angle water entry test launching device according to the location of the water entry point, and arrange the measuring equipment according to the location of the water entry point;

[0025] With the support plate and the support plate disconnected, slide the support plate on the arc-shaped guide rail, adjust the water entry angle of the projectile, and then fix the support plate and the support plate together.

[0026] The projectile is launched, and the measuring device measures the performance data of the projectile during its entry into the water.

[0027] The beneficial effects of this invention are as follows:

[0028] This invention features a compact and reasonable structure and is easy to operate. By setting an arc-shaped guide rail on the support plate, the support plate for mounting the launch tube slides on the arc-shaped guide rail, ensuring that the axis of the launch tube always passes through the center of the arc-shaped guide rail's trajectory. The center of the trajectory is used as the water entry point of the projectile. Water entry tests at different angles are conducted using a fixed-point water entry method, thereby reducing the requirements for the water area range of the water entry test and improving test efficiency under low-cost conditions.

[0029] Furthermore, the present invention also has the following advantages:

[0030] (1) An arc-shaped through hole is used as a circular arc guide rail, which combines the sliding structure and locking structure of the tray with the circular arc guide rail, simplifying the structure and manufacturing cost of the launching device.

[0031] (2) By setting a lifting ring that is rotatably connected to the support plate as a limiting support component at one end of the pull rod, and by screwing the first nut on the pull rod, the support plate is suspended on the lifting ring after the fixed connection with the support plate is released. The water entry angle can be adjusted by adjusting the position of the first nut on the pull rod. In addition, the rotational displacement is converted into the displacement in the length direction of the pull rod during the rotation of the first nut, so that the water entry angle can be adjusted not only by a single person, but also by fine adjustment.

[0032] (3) Using gunpowder as the launching power, the water entry speed can be quantitatively controlled by precisely adjusting the weight of the ignition powder. The fixed-point water entry method allows the small-angle water entry test of the projectile to be unrestricted by the size of the test pool, reducing the requirements for measuring equipment. When adjusting the water entry angle, rotating the first nut converts the rotational displacement into the displacement of the length direction of the pull rod, making the water entry angle adjustment more precise and allowing for single-person operation, improving the continuity of test condition parameters, increasing test efficiency and the richness of test data. Attached Figure Description

[0033] Figure 1 This is a schematic diagram of the structure of the present invention.

[0034] Figure 2 This is a schematic diagram of the structure of the present invention (another state).

[0035] Figure 3 This is the front view of the present invention.

[0036] Figure 4 This is a side view of the present invention.

[0037] Figure 5 for Figure 4 Enlarged view of a portion of point A in the middle.

[0038] Figure 6 for Figure 4 Enlarged view of section B in the middle.

[0039] in:

[0040] 1. Support plate; 11. Support; 12. Horizontal fixings; 13. Horizontal struts; 14. Lateral fixings;

[0041] 2. Arc-shaped guide rail; 3. Support plate; 31. Guide post; 32. Third nut;

[0042] 4. Launch tube; 41. Power unit; 42. Tube body; 43. Clamp;

[0043] 5. Tie rod; 51. Fourth nut; 52. Hinge shaft;

[0044] 6. Tension assembly; 61. First nut; 62. Eye; 63. Fifth nut; 64. Stud;

[0045] 7. Projectile firing;

[0046] 8. Second nut. Detailed Implementation

[0047] This application provides a launching device and a water entry test method for a projectile with a small angle of entry. Addressing the limitations of existing technologies, such as the limited water area in laboratory conditions making it difficult to provide a wide water area for small-angle water entry tests, and the limited measurement range of measuring equipment making it difficult to fully cover changing entry points, this method reduces the investment cost of measuring equipment and improves test efficiency. During the water entry test, the entry point of the projectile 7 is kept at a fixed position while adjusting its entry angle. This fixes the installation location of the measuring equipment, facilitating its arrangement and reducing the requirements for its detection range.

[0048] To better understand the above technical solutions, the following will provide a detailed explanation of the technical solutions in conjunction with the accompanying drawings and specific implementation methods.

[0049] Example 1:

[0050] like Figures 1-4 As shown, the projectile small-angle water entry test launching device of this embodiment includes a support plate 3, a launching tube 4, a support plate 1, an arc-shaped guide rail 2, and a locking structure. The support plate 3, the support plate 1, the arc-shaped guide rail 2, and the locking structure form an angle adjustment structure, which is used to adjust the direction of the smoothbore axis of the launching tube 4, thereby adjusting the water entry angle of the projectile 7.

[0051] The launch tube 4 is fixedly installed on the tray 3. The launch tube 4 is used to launch the projectile 7.

[0052] Support plate 1 is fixedly installed on one side of the test water tank;

[0053] The arc-shaped guide rail 2 is located on the support plate 1, and the support plate 3 is slidably connected to the arc-shaped guide rail 2;

[0054] The locking structure is used to detachably and securely connect the tray 3 to the support plate 1;

[0055] The axial direction of the smoothbore of the launch tube 4 always passes through the center of the trajectory of the arc-shaped guide rail 2, the water entry point of the projectile 7 is the center of the trajectory, and the length of the arc-shaped guide rail 2 is adapted to the adjustment range of the water entry angle of the projectile 7.

[0056] Specifically, the launch tube 4 is a smoothbore launch tube, which includes a tube body 42. A power unit 41 is installed at one end of the tube body 42. The projectile 7 is placed inside the tube body 42. The power unit 41 is gunpowder type. The high-pressure gas generated by the gunpowder propels the projectile 7 out of the tube body 42. By controlling the amount of gunpowder, the projectile 7 can have different launch velocities. The water entry velocity of the projectile 7 can be adjusted and controlled within the range of 50 to 300 m / s. The projectile 7 is a projectile model.

[0057] By adjusting the position of the support plate 3 on the arc-shaped guide rail 2, the projectile 7 can have different water entry angles, thereby achieving adjustable and controllable water entry speed and water entry angle of the projectile 7 within a certain range.

[0058] Before the test, the entire launching device needs to be installed at a certain height in the test pool, with the entry point at the water surface. The installation position is adjusted by changing the distance between the launching device and the water surface. Figure 2 As shown, the smoothbore axis of the launch tube 4 is placed flat on the water surface, so the center of the trajectory of the arc-shaped guide rail 2 is located at a point on the water surface.

[0059] like Figure 3 , Figure 4As shown, the support plate 1 is a vertically arranged flat plate structure. A support 11 is provided at the lower part of the support plate 1, and the support 11 is detachably and fixedly connected to a horizontal fixing element 12. The upper part of the support plate 1 is detachably and fixedly connected to a lateral fixing element 14 via a horizontal strut 13. Both the horizontal fixing element 12 and the lateral fixing element 14 are structures relatively fixed to the test water tank, providing a position for the launch device. The position of the water inlet is determined by adjusting the position of the support plate 1 relative to the horizontal fixing element 12 and the lateral fixing element 14. The horizontal fixing element 12 and the lateral fixing element 14 can be steel structures connected to the test water tank wall by welding, and the launch device is fixedly connected to them using fasteners.

[0060] After the launching device is installed, adjust the water entry angle of the projectile 7. After the fixed connection between the support plate 3 and the support plate 1 is released, let the support plate 3 slide along the trajectory of the arc-shaped guide rail 2. Use an angle meter to measure the angle between the smooth bore axis of the launching tube 4 and the horizontal plane. When the angle meets the water entry angle required for the test, fix the support plate 3 and the support plate 1 again.

[0061] The tail cap of the power unit 41 contains gunpowder, and the ignition wire is led out through the airtight wire connector of the latch body and connected to the test equipment. Before the test, the water entry speed is quantitatively controlled by precisely adjusting the weight of the ignition powder. The projectile 7 is inserted into one end of the tube body 42. At this time, the projectile 7 is fixed to the tube wall of the tube body 42 by friction through the O-ring.

[0062] During the test, the gunpowder was ignited, and projectile 7 was launched into the water. The measuring equipment measured the performance data of projectile 7 during its water entry process. The performance data included water entry cavitation, water entry trajectory stability, and underwater target depth residual velocity.

[0063] Typically, the measuring equipment used in the water entry test of a projectile includes a buffer tank, a light source, a high-speed video recorder, and an industrial control computer. The water entry angle for a small-angle water entry test is adjustable from 0 to 30 degrees. The arc-shaped guide rail 2 in this embodiment allows for continuous adjustment of the water entry angle. Because the launching device in this embodiment can enter the water at a fixed point, it does not require high-spec video recorders and light sources with wide coverage, thus reducing equipment investment costs.

[0064] By setting an arc-shaped guide rail 2 on the support plate 1, the support plate 3 for mounting the launch tube 4 slides on the arc-shaped guide rail 2, so that the axial direction of the smoothbore of the launch tube 4 always passes through the center of the trajectory circle of the arc-shaped guide rail 2, and the center of the trajectory circle is used as the water entry point of the projectile 7. Water entry tests at different angles are carried out by using a fixed-point water entry method, thereby reducing the requirements of the water area for water entry tests and improving test efficiency under low cost conditions.

[0065] The arc-shaped guide rail 2 can be a standard slide rail fixedly installed on the support plate 3. In order to reduce the manufacturing cost of the equipment, such as... Figures 1-3 As shown, the arc-shaped guide rail 2 in this embodiment includes an arc-shaped through hole on the support plate 1, and two guide posts 31 corresponding to an arc-shaped through hole are spaced apart on the support plate 3. Each guide post 31 is slidably connected to the arc-shaped through hole.

[0066] Specifically, the number of arc-shaped guide rails 2 on the tray 3 can be one or two, such as... Figure 1 , Figure 2 As shown, there are two concentric arc-shaped guide rails 2, which increases the connection stability between the support plate 3 and the support plate 1. When the arc-shaped through hole is used as the guide rail structure, in order to ensure that the axial direction of the slide tube 4 on the support plate 3 always passes through the center of the trajectory circle of the arc-shaped guide rail 2 during the attitude change process when the support plate 3 slides on the arc-shaped guide rail 2, the number of guide posts 31 corresponding to one arc-shaped through hole should be at least two. When there are two guide posts 31, the line connecting the center of the cross-section of the two guide posts 31 is perpendicular to the axial direction of the slide tube 4.

[0067] Regarding the structure of guide post 31, as follows: Figure 4 , Figure 6 As shown, one end of the guide post 31 is a threaded section, and the other end of the guide post 31 is a limiting head. The locking structure includes a third nut 32 that is screwed to the threaded section. When the third nut 32 is locked, the support plate 3 is fixedly connected to the support plate 1.

[0068] Specifically, the portion of the guide post 31 that contacts the arc-shaped through hole can be a light column, such as... Figure 6 As shown, when the third nut 32 is loosened, the distance between the third nut 32 and the limiting head is greater than the total thickness of the support plate 1 and the support plate 3, and the guide post 31 can slide in the arc-shaped through hole. When the third nut 32 is locked, the distance between the third nut 32 and the limiting head is equal to the total thickness of the support plate 3 and the support plate 1, and the support plate 3 is fixedly connected to the support plate 1.

[0069] An arc-shaped through hole is used as the arc-shaped guide rail 2. The sliding and locking structures of the support plate 3 and the arc-shaped guide rail 2 are combined to simplify the structure and reduce the manufacturing cost of the launching device.

[0070] Guide post 31 uses standard bolts, reducing manufacturing costs.

[0071] like Figure 4 , Figure 5 As shown, a clamp 43 is provided on the tray 3, which is used to detachably and fix the launch tube 4 to the tray 3.

[0072] Example 2:

[0073] Because the fixed connection between the support plate 3 and the support plate 1 needs to be released during the adjustment of the water entry angle, the overall weight of the support plate 3 and the launch tube 4 mounted on the support plate 3, as well as the installation structure of the support plate 3, dictate that multiple people are required to work together to adjust the angle of the smoothbore axis of the launch tube 4. When the requirements for the incident angle are strict and the gradient division of the incident angle is fine, the manpower and time costs of the experiment will increase significantly.

[0074] Furthermore, such as Figures 3-5 As shown, the projectile small-angle water entry test launching device of this embodiment, based on the first embodiment, also includes an auxiliary adjustment structure. The auxiliary adjustment structure includes a pull rod 5 and a tension assembly 6 installed on the upper part of the support plate 1. One end of the pull rod 5 is hinged to the support plate 3, and the other end of the pull rod 5 is connected to the tension assembly 6. By changing the length of the pull rod 5 below the tension assembly 6, the size of the water entry angle can be adjusted.

[0075] The tension assembly 6 includes a lifting ring 62 with one end rotatably connected to the support plate 1, a pull rod 5 slidably connected to a through hole on the lifting ring 62, the pull rod 5 is a screw rod, and a first nut 61 is screwed onto the pull rod 5. The first nut 61 cooperates with the lifting ring 62 to limit the length of the pull rod 5 below the tension assembly 6.

[0076] It also includes a second nut 8 that is screwed to the pull rod 5. The second nut 8 and the first nut 61 are located on both sides of the lifting ring 62. When the first nut 61 and the second nut 8 are in contact with the lifting ring 62 at the same time, the pull rod 5 is fixedly connected to the lifting ring 62.

[0077] Specifically, one end of the pull rod 5 is provided with a hinge hole, and a hinge shaft 52 is fixedly provided on the support plate 3. The hinge hole fits onto the hinge shaft to hinge the pull rod 5 to the support plate 3. A fourth nut 51 is installed on the hinge shaft 52 to prevent the hinge hole from disengaging from the hinge shaft 52. The lifting ring 62 is a component similar to a lifting ring bolt structure. The lifting ring 62 includes a ring body with a through hole in the middle. A stud 64 is fixedly provided on one side of the ring body. The stud 64 passes through a circular through hole in the upper part of the support plate 1. Figure 5 As shown, a fifth nut 63 is installed at the end of the stud 64 to limit the stud 64 so that it does not come out of the circular through hole. At the same time, the lifting ring 62 can rotate relative to the support plate 1. The axis of rotation of the lifting ring 62, i.e. the axis of the stud 64, is perpendicular to the axis of the pull rod 5.

[0078] During the test preparation phase, when adjusting the water entry angle of projectile 7:

[0079] Step 1: After loosening the four nuts 32, 8, 51, and 63, the support plate 3 can slide on the arc-shaped guide rail 2. At this time, due to the effect of gravity and the limiting effect of the lifting ring 62 on the pull rod 5 through the first nut 61, the length of the pull rod 5 below the tension assembly 6 is a fixed value. When the pull rod 5 is pulled upward, the first nut 61 disengages from the lifting ring 62, and the support plate 3 can slide upward.

[0080] The second step is to adjust the water entry angle by operating the second nut 8 according to the target value and the current water entry angle. When the current water entry angle is less than the target value, use a tool to rotate the second nut 8 so that the second nut 8 moves toward the support plate 3, reducing the length of the pull rod 5 below the tension assembly 6 until the water entry angle is equal to the target value. When the current water entry angle is greater than the target value, use a tool to rotate the second nut 8 so that the second nut 8 moves away from the support plate 3, increasing the length of the pull rod 5 below the tension assembly 6 until the water entry angle is equal to the target value.

[0081] When there is a large difference between the target value and the current water entry angle, before proceeding to the second step, the pull rod 5 can be slid upward in the hole of the lifting ring 62 by lifting the support plate 3, and the position of the first nut 61 on the pull rod 5 can be roughly adjusted by rotating the first nut 61. After the first nut 61 contacts the lifting ring 62, the angle can be finely adjusted by using the method in the second step.

[0082] Third step: After the angle adjustment is completed, tighten the four third nuts 32 to fix the support plate 1 and the support plate 3 in the plate thickness direction. After rotating the second nut 8 upward, the first nut 61 and the second nut 8 will contact the lifting ring 62 at the same time to fix the pull rod 5 to the lifting ring 62. The position of the support plate 3 relative to the support plate 1 is restricted from the direction of movement of the support plate 3. Therefore, the locking structure also includes the second nut 8.

[0083] Fourth step: Tighten the fourth nut 51 and the fifth nut 63 to reduce the possibility of the pull rod 5 shaking and further improve the stability of the water entry angle.

[0084] The above-mentioned adjustment of the water entry angle of projectile 7 allows for single-person operation.

[0085] By setting a lifting ring 62 that is rotatably connected to the support plate 1 as a limiting support component at one end of the pull rod 5, and by screwing a first nut 61 onto the pull rod 5, the support plate 3 is suspended on the lifting ring 62 after the fixed connection with the support plate 1 is released. The water entry angle can be adjusted by adjusting the position of the first nut 61 on the pull rod 5. In addition, the rotational displacement is converted into the displacement in the length direction of the pull rod 5 during the rotation of the first nut 61, so that the water entry angle can not only be operated by a single person, but also can be adjusted with precision.

[0086] Example 3:

[0087] The projectile small-angle water entry test method of this embodiment includes the following steps:

[0088] Determine the location of the water entry point for projectile 7;

[0089] Install the small-angle water entry test launching device according to the location of the water entry point, and arrange the measuring equipment according to the location of the water entry point;

[0090] With the support plate 3 and the support plate 1 disconnected, slide the support plate 3 on the arc-shaped guide rail 2, adjust the water entry angle of the projectile 7, and then fix the support plate 3 and the support plate 1 in place.

[0091] Launch projectile 7, which enters the water from the entry point. The measuring equipment measures the performance data of projectile 7 during its entry into the water.

[0092] Before launching Projectile 7, after confirming that the wiring is correct, connect the ignition wire to the industrial control computer and measure the resistance. Then, activate the recording and backlighting via the industrial control computer, and set the high-speed recorder to a ready-to-trigger state.

[0093] When launching projectile 7, the industrial control computer simultaneously provides the voltage signal for the propellant and the trigger signal for the high-speed video recorder, and begins data acquisition at the same time. Projectile 7 enters the water at a certain speed and angle. After the predetermined time is reached, the lights and the high-speed video recorder are turned off, and the test is completed. The acquired data can then be processed.

[0094] The launch method of projectile 7 using high-pressure gas catapults such as hydrogen cannons leads to unstable initial launch velocity. The small-angle water entry test method of this embodiment uses gunpowder as the launch power. The water entry velocity can be quantitatively controlled by precisely adjusting the weight of the ignition powder. The fixed-point water entry method eliminates the size limitations of the test pool, reducing the requirements for measuring equipment. When adjusting the water entry angle, rotating the first nut 61 converts the rotational displacement into the length displacement of the pull rod 5, making the adjustment of the water entry angle precise and allowing for single-person operation. This improves the continuity of test condition parameters, increases test efficiency, and enhances the richness of test data.

[0095] The above description is an explanation of the present invention and not a limitation thereof. The scope of the present invention is defined by the claims. Within the scope of protection of the present invention, any form of modification may be made.

Claims

1. A launching device for a small-angle water entry test of a projectile, characterized in that: include A tray (3) is fixedly mounted with a launch tube (4), which is used to launch the projectile (7). Support plate (1), which is fixedly installed on one side of the test water tank; An arc-shaped guide rail (2) is located on the support plate (1), and the support plate (3) is slidably connected to the arc-shaped guide rail (2). A locking structure is provided for detachably and fixedly connecting the tray (3) to the support plate (1); The smoothbore axis of the launching tube (4) always passes through the center of the trajectory of the arc-shaped guide rail (2), the water entry point of the projectile (7) is the center of the trajectory, and the length of the arc-shaped guide rail (2) is adapted to the adjustment range of the water entry angle of the projectile (7); It also includes an auxiliary adjustment structure, which includes a pull rod (5) and a tension assembly (6) installed on the upper part of the support plate (1). One end of the pull rod (5) is hinged to the support plate (3), and the other end of the pull rod (5) is connected to the tension assembly (6). By changing the length of the pull rod (5) below the tension assembly (6), the size of the water entry angle can be adjusted. The tension assembly (6) includes a ring (62) with one end rotatably connected to the support plate (1), a pull rod (5) slidably connected to a through hole on the ring (62), the pull rod (5) is a screw rod, and a first nut (61) is screwed onto the pull rod (5). The first nut (61) cooperates with the ring (62) to limit the length of the pull rod (5) below the tension assembly (6).

2. The projectile small-angle water entry test launching device as described in claim 1, characterized in that: It also includes a second nut (8) screwed to the pull rod (5). The second nut (8) and the first nut (61) are located on both sides of the lifting ring (62). When the first nut (61) and the second nut (8) are in contact with the lifting ring (62) at the same time, the pull rod (5) and the lifting ring (62) are fixedly connected.

3. The projectile small-angle water entry test launching device as described in claim 1, characterized in that: The arc-shaped guide rail (2) includes an arc-shaped through hole on the support plate (1), and two guide posts (31) corresponding to an arc-shaped through hole are spaced apart on the support plate (3). Each guide post (31) is slidably connected to the arc-shaped through hole.

4. The projectile small-angle water entry test launching device as described in claim 3, characterized in that: One end of the guide post (31) is a threaded section, and the other end of the guide post (31) is a limiting head. The locking structure includes a third nut (32) screwed to the threaded section. When the third nut (32) is locked, the support plate (3) is fixedly connected to the support plate (1).

5. The projectile small-angle water entry test launching device as described in claim 4, characterized in that: The guide post (31) is a standard bolt.

6. The projectile small-angle water entry test launching device as described in claim 3, characterized in that: The number of the arc-shaped guide rails (2) is two, and they are arranged concentrically.

7. The projectile small-angle water entry test launching device as described in claim 1, characterized in that: The tray (3) is provided with a clamp (43), which is used to detachably and fix the launching tube (4) to the tray (3).

8. A method for testing projectiles entering water at a small angle, characterized in that: Includes the following steps: Determine the location of the water entry point of the projectile (7); Install the projectile small-angle water entry test launching device as described in claim 1 according to the location of the water entry point, and arrange the measuring equipment according to the location of the water entry point; When the support plate (3) and the support plate (1) are disconnected, slide the support plate (3) on the arc-shaped guide rail (2), adjust the water entry angle of the projectile (7), and then fix the support plate (3) and the support plate (1) together. The projectile (7) is launched, and the measuring device measures the performance data of the projectile (7) during its entry into the water.

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