Parallel stage separation free-flight wind tunnel test apparatus can be provided for normal separation speed

Abstract

The application discloses a parallel interstage separation free-flight wind tunnel test device which can provide normal separation speed, comprising a first model, a second model, a pull pin rope, a cover plate, a pull pin, a first model unlocking device and a second model unlocking device; the cover plate is installed on the first model, and the first model unlocking device is installed in the concave cavity of the cover plate; the second model unlocking device is installed in the second model; the pull pin rope is connected to the tail end of the pull pin; in the locked state, the second model is placed on the cover plate; the two model unlocking devices are locked through the pull pin; when unlocking and separating, the pull pin is pulled out by external force acting on the pull pin rope, the two model unlocking devices are separated, and the second model is pushed out; the application can ensure that the two-stage model is fixed as a whole before separation, and the separation is quickly and effectively carried out, and the shape is preserved to the maximum extent, thereby solving the problem that the longitudinal space of the parallel interstage separation free-flight model is small, and the normal initial speed which can ensure safe separation cannot be provided.

Description

Technical Field

[0001] This invention belongs to the field of model free-flight wind tunnel testing technology, and particularly relates to a parallel-stage separation free-flight wind tunnel testing device that can provide normal separation velocity. Background Technology

[0002] Wind tunnel testing of free-flight models is a commonly used method for studying the dynamic aerodynamic characteristics of aircraft, and it can also be used to study multi-body interference. The basic method involves launching the model at high speed against the airflow direction after the wind tunnel flow field has stabilized. The model will then fly freely in the wind tunnel for a short period, verifying the safety of multi-stage separation. Simultaneously, high-speed photography is used to capture the model's free-flight attitude trajectory through an observation window, allowing for the acquisition of the aircraft's dynamic aerodynamic parameters after data processing.

[0003] The wind tunnel test for free-flight between parallel stages requires that the first and second models exist as a rigid whole before separation, with no relative degrees of freedom. After unlocking, all degrees of freedom of the first and second models are released, allowing each to perform independent six-degree-of-freedom motion. However, due to the aerodynamic compression of the head of the parallel-stage separation model, without a normal separation velocity, collisions are likely to occur after releasing the degrees of freedom of the two stages, making safe separation impossible. This necessitates that the separation unlocking test device meet the following requirements: ensuring that the two-stage aircraft models are fixed together as a rigid whole before separation; providing a sufficiently large normal separation velocity during separation; allowing each stage to perform independent six-degree-of-freedom motion after separation; and avoiding damage to the shape of the aircraft models.

[0004] Because the longitudinal space of parallel-stage aircraft models is small, there is insufficient maneuvering space, making it impossible for previous wind tunnel testing techniques for parallel-stage separation to provide initial normal separation velocities for both stages. This often results in collisions under various conditions, making safe separation of the parallel aircraft impossible. Therefore, there is a need to develop a wind tunnel testing device for parallel-stage separation that can provide initial normal separation velocities. Summary of the Invention

[0005] The technical problem solved by this invention is to overcome the shortcomings of the prior art and provide a wind tunnel test device for parallel-stage separation free flight that can provide normal separation velocity. Before separation, it can ensure that the two-stage aircraft model is fixed as a rigid whole. During separation, it can provide sufficient normal separation initial velocity. After separation, the two-stage model performs independent six-degree-of-freedom motion, while avoiding damage to the shape of the aircraft model. This allows the parallel aircraft to separate safely in the wind tunnel and meets the test requirements.

[0006] To solve the above-mentioned technical problems, the present invention discloses a parallel stage separation free-flying wind tunnel test device that can provide normal separation velocity, comprising: a first model, a second model, a pull pin rope, a cover plate, a pull pin, a first model unlocking device, and a second model unlocking device.

[0007] The cover plate is installed on the first model, and the unlocking device of the first model is installed in the cavity of the cover plate; the unlocking device of the second model is connected and fixed to the second model and installed inside the second model; the end of the pull pin is connected to the pull pin rope.

[0008] In the locked state: The second model, equipped with the second model unlocking device, is placed on the cover plate; the first model unlocking device and the second model unlocking device are locked by a pull pin;

[0009] During unlocking and separation: the external force acting on the pull pin rope is used to pull out the pull pin, the first model unlocking device is separated from the second model unlocking device, and the second model is pushed out, thus realizing the separation of the two-stage model.

[0010] In the above-mentioned parallel-stage separation free-flying wind tunnel test device that can provide normal separation velocity, the first model is characterized by having a cover plate mounting groove on its upper end face for mounting a cover plate, and the cover plate mounting groove is provided with a threaded hole a for connecting and fixing the cover plate.

[0011] In the above-mentioned parallel-stage free-flight wind tunnel test device that can provide normal separation velocity, the first model unlocking device includes: an unlocking cover, a push rod, and a spring; wherein, the spring is fitted on the push rod, and the push rod and the spring are installed together in the cavity of the cover plate through the unlocking cover.

[0012] In the aforementioned parallel-stage free-flight wind tunnel test apparatus that can provide normal separation velocity,

[0013] The upper end face of the cover plate is provided with a threaded hole b and a cylindrical protrusion; wherein, the threaded hole b cooperates with the threaded hole a to realize the connection and fixation of the cover plate and the first model; the cylindrical protrusion is used to install and position the second model and constrain the degree of freedom of the second model;

[0014] The cover plate has a recessed cavity in the middle; a circular through hole a is provided at the center of the bottom of the recessed cavity; one end of the push rod passes through the inner ring of the spring and is inserted into the circular through hole a; the unlocking cover is screwed into the recessed cavity to limit the push rod and the spring as a whole in the recessed cavity; the push rod can move up and down in the recessed cavity and compress the spring.

[0015] A circular through hole b is provided on the side of the cavity; when the spring is compressed to a predetermined position, the pin is inserted through the circular through hole b to prevent the spring from popping out, which facilitates the installation of the second model and the unlocking device of the second model.

[0016] A circular through hole c is provided on the upper side of the cavity; wherein, the circular through hole c is used to hold the pull pin in the locked state.

[0017] In the aforementioned parallel-stage free-flight wind tunnel test apparatus that can provide normal separation velocity,

[0018] The bottom of the second model is provided with a threaded hole c for installing the unlocking device of the second model and a storage groove; wherein, the threaded hole c is located at the center of the bottom of the second model, and the two storage grooves are located on both sides of the threaded hole c;

[0019] The bottom of the second model is provided with a circular blind hole; when the second model is placed on the cover plate, the cylindrical protrusion is inserted into the circular blind hole to install and position the second model and constrain the degree of freedom of the second model.

[0020] In the above-mentioned parallel-stage separation free-flying wind tunnel test device that can provide normal separation velocity, the second model unlocking device includes: unlocking stud, first rotating shaft, second rotating shaft, first torsion spring, second torsion spring, first support rod and second support rod;

[0021] The top side of the unlocking stud is provided with a thread 'a' for screwing into the threaded hole 'c'; the bottom of the unlocking stud is provided with a stud groove to provide space for the rotation of the first and second support rods; the side of the stud groove is provided with circular through holes 'd' and 'e', ​​which are symmetrically arranged along the axis of the unlocking stud for installing the first and second rotating shafts.

[0022] A first torsion spring is placed in the groove at the top of the first support rod. A first rotating shaft passes through a circular through hole d and the first torsion spring, fixing one end of the first support rod in the stud groove. A second torsion spring is placed in the groove at the top of the second support rod. A second rotating shaft passes through a circular through hole e and the second torsion spring, fixing the other end of the second support rod in the stud groove. In its natural state, under the action of the first and second torsion springs, the first and second support rods are horizontal. After applying torque, the first and second support rods can rotate around the first and second rotating shafts to a vertical state.

[0023] In the aforementioned parallel-stage free-flight wind tunnel test apparatus that can provide normal separation velocity,

[0024] The unlocking cover has a thread b and a circular through hole f on its side; the thread b is used to screw into the cavity; the circular through hole f is used to lock the pull pin in the locked state.

[0025] A circular through hole g is provided on the bottom side of the unlocking cover. When the spring is compressed to the predetermined position, the circular through hole g is coaxial with the circular through hole b. The pin is inserted from the circular through hole b into the circular through hole g to restrict the spring from popping out, which facilitates the installation of the second model and the unlocking device of the second model.

[0026] The top of the unlocking cover has a square hole, and square grooves are provided on both sides of the square hole; the square hole is used to insert the first support rod and the second support rod; the square grooves make it easy for the operator to rotate the unlocking cover to achieve the screw connection between the unlocking cover and the cavity.

[0027] In the aforementioned parallel-stage free-flight wind tunnel test apparatus that can provide normal separation velocity, the first and second support rods are two support rods with identical structures, symmetrically arranged along the axis of the unlocking stud; wherein:

[0028] The top of the support rod is provided with a rounded chamfer to facilitate the rotation of the support rod around the pivot.

[0029] The top side of the support rod is provided with a pivot mounting hole for mounting the pivot;

[0030] The top of the support rod is provided with a torsion spring mounting groove for mounting a torsion spring;

[0031] A circular through hole h is provided on the bottom side of the support rod to lock the pull pin in the locked state;

[0032] The support rod has a limiting groove on its side to hold the torsion spring wire, which serves to position and maintain its shape.

[0033] In the aforementioned parallel-stage free-flight wind tunnel test apparatus that can provide normal separation velocity,

[0034] During installation, the cover plate is fixed to the first model; the first model unlocking device is installed in the cavity of the cover plate; the second model unlocking device is connected and fixed to the second model; the first and second support rods are rotated to a vertical position and inserted into the square hole of the unlocking cover. The first and second support rods are constrained by the square hole and are in a vertical position. The receiving groove is sealed with thin tin foil to maintain its shape; the push rod is pressed down to compress the spring, so that the circular through holes at the bottom of the first and second support rods are aligned with the circular through holes f and c. The pull pin is inserted to lock the device in the locked state.

[0035] During unlocking and separation: the external force acting on the pull pin rope is used to pull out the pull pin, the spring releases elastic potential energy, and pushes out the second model, realizing the separation of the two models; after separation, the first and second support rods lose the constraint of the square hole, and rotate to the horizontal position under the action of the first and second torsion springs, piercing the thin tin foil and being put into the storage groove, preventing the second model unlocking device from being exposed.

[0036] In the above-mentioned parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity, the first model is a scaled-down model of the first stage of a physical aircraft, and the second model is a scaled-down model of the second stage of a physical aircraft; the centers of mass of the first model and the second model are located on the same axis, and the center of mass of the combined body formed before the separation of the first model and the second model is located inside the first model.

[0037] The present invention has the following advantages:

[0038] (1) This invention discloses a wind tunnel test device for parallel-stage separation free-flight that can provide a normal separation velocity, solving the problem that previous parallel-stage separation free-flight tests could not provide a normal separation initial velocity. Due to the small longitudinal space of parallel aircraft, there is not enough room for maneuver, making it impossible for existing parallel-stage separation free-flight wind tunnel test technology to provide a normal separation initial velocity and to simulate separation conditions with a normal separation initial velocity. This invention can ensure that the two-stage aircraft model is fixed as a rigid whole before separation, and can provide a sufficient normal separation initial velocity during separation. After separation, the two-stage model performs independent six-degree-of-freedom motion, which can effectively simulate the parallel-stage separation condition with a normal separation initial velocity.

[0039] (2) This invention discloses a wind tunnel test device for parallel-stage separation free-flight that can provide a normal separation velocity. While providing an initial normal separation velocity, it can also restore the model's shape to the greatest extent possible. Besides providing an initial normal separation velocity, parallel-stage separation free-flight also requires the two stages of the aircraft to be fixed as a rigid whole before separation. This inevitably leads to some parts of the second model needing to be connected to the first model. Traditional piston-type separation devices can retract the connecting parts into the first model to maintain their shape, but because the piston rod cannot be fixedly connected to the second model, the required normal separation velocity cannot be achieved. This invention uses a combination of a support rod and a torsion spring, which allows the connecting parts to retract into the second model to maintain their shape while avoiding piston impact, ensuring that the required normal separation velocity is achieved.

[0040] (3) This invention discloses a parallel stage separation free-flying wind tunnel test device that can provide normal separation velocity. After the unlocking separation device is unlocked, it remains inside the model. The pull pin moves away from the test model quickly with the pull pin rope, avoiding the risk of the unlocking device popping out of the model and moving in the flow field, interfering with the test or even colliding with the model.

[0041] (4) This invention discloses a parallel-stage free-flying wind tunnel test device that can provide normal separation velocity. Different types of springs can be replaced to change the normal separation velocity. Using the laws of conservation of momentum and energy, the required elastic potential energy is calculated based on the required normal separation velocity, thereby selecting the appropriate type of spring. Attached Figure Description

[0042] Figure 1 This is an isometric view of a parallel-stage separation free-flying wind tunnel test device that can provide normal separation velocity in an embodiment of the present invention before unlocking and separation;

[0043] Figure 2 This is a full cross-sectional view of a parallel-stage free-flying wind tunnel test device that can provide normal separation velocity before unlocking and separation, according to an embodiment of the present invention.

[0044] Figure 3 This is a full cross-sectional view of a parallel-stage free-flying wind tunnel test device that can provide normal separation velocity after unlocking and separation, according to an embodiment of the present invention.

[0045] Figure 4 This is a schematic diagram of the installation of a first model, a cover plate, and a second model in an embodiment of the present invention;

[0046] Figure 5 This is an exploded schematic diagram of a first model unlocking device and a second model unlocking device according to an embodiment of the present invention;

[0047] Figure 6 This is a schematic diagram of the structure of an unlocking cover in an embodiment of the present invention;

[0048] Figure 7 This is a schematic diagram of the operation of a second model unlocking device in an embodiment of the present invention;

[0049] Figure 8 This is an exploded schematic diagram of a second model unlocking device in an embodiment of the present invention. Detailed Implementation

[0050] To make the objectives, technical solutions, and advantages of the present invention clearer, the embodiments disclosed in the present invention will be described in further detail below with reference to the accompanying drawings.

[0051] Reference Figures 1-3 In this embodiment, the parallel-stage separation free-flight wind tunnel test device that provides normal separation velocity includes: a first model 1, a second model 2, a pull pin rope 3, a cover plate 4, a pull pin 5, a first model unlocking device, and a second model unlocking device. The cover plate 4 is mounted on the first model 1, and the first model unlocking device is installed within a cavity 404 of the cover plate 4. The second model unlocking device is connected and fixed to the second model 2 and installed within the second model 2. The pull pin 5 is connected at its end to the pull pin rope 3. In the locked state: the second model 2, with the second model unlocking device installed, is placed on the cover plate 4; the first and second model unlocking devices are locked together by the pull pin 5. During unlocking and separation: the pull pin 5 is pulled out using an external force acting on the pull pin rope 3, separating the first and second model unlocking devices and pushing out the second model 2, thus achieving the separation of the two-stage models.

[0052] In this embodiment, the first model 1 is a scaled-down model of the first stage of the physical aircraft, and the second model 2 is a scaled-down model of the second stage of the physical aircraft; the centers of mass of the first model 1 and the second model 2 are located on the same axis, and the center of mass of the combined body formed before the separation of the first model 1 and the second model 2 is located inside the first model 1.

[0053] In this embodiment, as Figure 4As shown, the upper surface of the first model 1 is provided with a cover plate mounting groove 102 for mounting the cover plate 4, and the cover plate mounting groove 102 is provided with a threaded hole a101 for connecting and fixing the cover plate 4.

[0054] In this embodiment, as Figure 3 The first model unlocking device shown mainly includes: an unlocking cover 6, a push rod 7, and a spring 8. The spring 8 is mounted on the push rod 7, and the push rod 7 and the spring 8 are installed together in the cavity 404 of the cover plate 4 through the unlocking cover 6.

[0055] In this embodiment, as Figures 2-4 As shown, the upper surface of the cover plate 4 is provided with a threaded hole b401 and a cylindrical protrusion 402; the threaded hole b401 cooperates with the threaded hole a101 to realize the connection and fixation of the cover plate 4 and the first model 1; the cylindrical protrusion 402 is used to install and position the second model 2 and constrain the degree of freedom of the second model 2. A cavity 404 is provided in the middle of the cover plate 4; a circular through hole a405 is provided at the center of the bottom of the cavity 404; one end of the push rod 7 passes through the inner ring of the spring 8 and is inserted into the circular through hole a405, which can play the role of positioning and constraining the axial movement of the push rod 7; the unlocking cover 6 is screwed to the cavity 404 to limit the push rod 7 and the spring 8 as a whole in the cavity 404; the push rod 7 can move up and down in the cavity 404 and compress the spring 8. A circular through hole b406 is provided on the side of the cavity 404; when the spring 8 is compressed to the predetermined position, the pin is inserted through the circular through hole b406 to prevent the spring 8 from popping out, which facilitates the installation of the second model 2 and the second model unlocking device. A circular through hole c403 is provided on the upper side of the cavity 404; the circular through hole c403 is used to hold the pull pin 5 in the locked state.

[0056] In this embodiment, as Figure 4 As shown, the bottom of the second model 2 is provided with a threaded hole c201 for installing the second model unlocking device and a storage groove 203; the threaded hole c201 is located at the center of the bottom of the second model 2, and the two storage grooves 203 are located on both sides of the threaded hole c201. A circular blind hole 202 is provided on the bottom of the second model 2; when the second model 2 is placed on the cover plate 4, the cylindrical protrusion 402 is inserted into the circular blind hole 202 to install and position the second model 2 and constrain the degree of freedom of the second model 2.

[0057] In this embodiment, as Figure 5As shown, the second model unlocking device mainly includes: an unlocking stud 9, a first rotating shaft 10, a second rotating shaft 11, a first torsion spring 12, a second torsion spring 13, a first support rod 14, and a second support rod 15. The top side of the unlocking stud 9 is provided with a thread a901 for screwing into a threaded hole c201; the bottom of the unlocking stud 9 is provided with a stud groove 902 to provide space for the rotation of the first support rod 14 and the second support rod 15; the side of the stud groove 902 is provided with circular through holes d903 and e904, which are symmetrically arranged along the axis of the unlocking stud 9 for installing the first rotating shaft 10 and the second rotating shaft 11. The first torsion spring 12 is placed in the top groove of the first support rod 14. The first rotating shaft 10 passes through the circular through hole d903 and the first torsion spring 12, fixing one end of the first support rod 14 in the stud groove 902. The second torsion spring 13 is placed in the top groove of the second support rod 15. The second rotating shaft 11 passes through the circular through hole e904 and the second torsion spring 13, fixing the other end of the second support rod 15 in the stud groove 902. In its natural state, under the action of the first torsion spring 12 and the second torsion spring 13, the first support rod 14 and the second support rod 15 are in a horizontal state. After applying torque, the first support rod 14 and the second support rod 15 can rotate around the first rotating shaft 10 and the second rotating shaft 11 to a vertical state.

[0058] In this embodiment, as Figure 6 As shown, the unlocking cover 6 has a threaded hole b601 and a circular through hole f605 on its side; the threaded hole b601 is used to screw into the cavity 404; the circular through hole f605 is used to hold the pull pin 5 in the locked state. The bottom side of the unlocking cover 6 has a circular through hole g602. When the spring 8 is compressed to a predetermined position, the circular through hole g602 is coaxial with the circular through hole b406. Inserting the pin from the circular through hole b406 into the circular through hole g602 restricts the spring 8 from popping out, facilitating the installation of the second model 2 and the unlocking device of the second model. The top of the unlocking cover 6 has a square hole 603, and square grooves 604 are provided on both sides of the square hole 603; the square hole 603 is used to insert the first support rod 14 and the second support rod 15; the square grooves 604 facilitate the operator to rotate the unlocking cover 6, achieving the screwed connection between the unlocking cover 6 and the cavity 404.

[0059] In this embodiment, as Figures 7-8 As shown, the first support rod 14 and the second support rod 15 are two support rods with identical structures, symmetrically arranged along the axis of the unlocking stud 9. Specifically: the top of the support rod has a circular chamfer 1401 to facilitate rotation around the pivot; the top side of the support rod has a pivot mounting hole 1402 for mounting the pivot; the top of the support rod has a torsion spring mounting groove 1403 for mounting the torsion spring; the bottom side of the support rod has a circular through hole h1404 to hold the pull pin 5 in the locked state; and the side of the support rod has a limiting groove 1405 to hold the torsion spring wire, serving a positioning and shape-preserving function.

[0060] In this embodiment, during installation, the cover plate 4 is fixed to the first model 1; the first model unlocking device is installed in the cavity 404 of the cover plate 4; the second model unlocking device is connected and fixed to the second model 2; the first support rod 14 and the second support rod 15 are rotated to a vertical state and inserted into the square hole 603 of the unlocking cover 6. The first support rod 14 and the second support rod 15 are constrained by the square hole 603 and are in a vertical state. The receiving groove 203 is sealed with thin tin foil to maintain its shape; the push rod 7 is pressed down to compress the spring 8, so that the circular through holes at the bottom of the first support rod 14 and the second support rod 15 are aligned with the circular through holes f605 and c403. The pull pin 5 is inserted to lock the device in a locked state. During unlocking and separation: the external force acting on the pull pin rope 3 is used to pull out the pull pin 5, the spring 8 releases elastic potential energy, and pushes out the second model 2, realizing the separation of the two-stage model; after separation, the first support rod 14 and the second support rod 15 lose the constraint of the square hole 603, and rotate to the horizontal position under the action of the first torsion spring 12 and the second torsion spring 13, piercing the thin tin foil and being put into the storage groove 203, preventing the second model unlocking device from being exposed, thereby ensuring that the second model 2 is as similar as possible to the aerodynamic shape of the real aircraft.

[0061] In this embodiment, the required normal separation speed can be changed by replacing the spring 8 with a different model. The specific selection method for the spring 8 is as follows:

[0062] The required normal separation velocity for the experiment is v. The total mass of the first model is m1, and the total mass of the second model is m2. Neglecting the mass of the push rod, the normal velocities v1 and v2 of the first and second models are calculated using the law of conservation of momentum:

[0063]

[0064] Using the law of conservation of energy and neglecting energy losses such as friction, the required elastic potential energy E is:

[0065]

[0066] Through actual experiments, it was found that, under actual conditions with energy loss, the required elastic potential energy of the spring is approximately twice that under ideal conditions. Therefore, the elastic potential energy E that the selected spring needs to release within the concave space of the cover plate is... 实际 =2E, the working space inside the cavity is x, then the required spring stiffness k is:

[0067]

[0068] Then, springs are selected based on stiffness and size.

[0069] In summary, the two-part unlocking device can ensure that the two-stage aircraft model is fixed as a rigid whole before separation, provide sufficient initial normal separation velocity during separation, and allow the two-stage model to perform independent six-degree-of-freedom motion after separation, while avoiding damage to the shape of the aircraft model, so that the parallel aircraft can be safely separated in the wind tunnel and meet the test requirements.

[0070] Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make possible changes and modifications to the technical solutions of the present invention by utilizing the methods and techniques disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solutions of the present invention shall fall within the protection scope of the technical solutions of the present invention.

[0071] The contents not described in detail in this specification are common knowledge to those skilled in the art.

Claims

1. A parallel-stage free-flight wind tunnel test device that can provide normal separation velocity, characterized in that, include: First model (1), second model (2), pull pin rope (3), cover plate (4), pull pin (5), first model unlocking device and second model unlocking device; wherein, the cover plate (4) is installed on the first model (1), and the first model unlocking device is installed in the cavity (404) of the cover plate (4); the second model unlocking device is connected and fixed to the second model (2) and installed in the second model (2); the end of the pull pin (5) is connected to the pull pin rope (3); in the locked state: the second model (2) with the second model unlocking device is placed on the cover plate (4); the first model unlocking device and the second model unlocking device are locked by the pull pin (5); when unlocking and separating: the pull pin (5) is pulled out by the external force acting on the pull pin rope (3), the first model unlocking device and the second model unlocking device are separated, and the second model (2) is pushed out, realizing the separation of the two models; The second model unlocking device includes: an unlocking stud (9), a first rotating shaft (10), a second rotating shaft (11), a first torsion spring (12), a second torsion spring (13), a first support rod (14), and a second support rod (15); wherein, the top side of the unlocking stud (9) is provided with a thread a (901) for screwing into the threaded hole c (201) at the bottom of the second model (2); the bottom of the unlocking stud (9) is provided with a stud groove (902) to provide space for the rotation of the first support rod (14) and the second support rod (15); the side of the stud groove (902) is provided with a circular through hole d (903) and a circular through hole e (904), which are symmetrically arranged along the axis of the unlocking stud (9) for installing the first rotating shaft (10) and the second rotating shaft (11). The first torsion spring (12) is placed in the top groove of the first support rod (14), and the first rotating shaft (10) passes through the circular through hole d (903) and the first torsion spring (12) to fix one end of the first support rod (14) in the stud groove (902); the second torsion spring (13) is placed in the top groove of the second support rod (15), and the second rotating shaft (11) passes through the circular through hole e (904) and the second torsion spring (13) to fix the other end of the second support rod (15) in the stud groove (902); in the natural state, under the action of the first torsion spring (12) and the second torsion spring (13), the first support rod (14) and the second support rod (15) are in a horizontal state; after applying torque, the first support rod (14) and the second support rod (15) can rotate around the first rotating shaft (10) and the second rotating shaft (11) to a vertical state.

2. The parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity according to claim 1, characterized in that, The upper surface of the first model (1) is provided with a cover plate mounting groove (102) for mounting the cover plate (4), and the cover plate mounting groove (102) is provided with a threaded hole a (101) for connecting and fixing the cover plate (4).

3. The parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity according to claim 2, characterized in that, The first model unlocking device includes: an unlocking cover (6), a push rod (7) and a spring (8); wherein the spring (8) is fitted on the push rod (7), and the push rod (7) and the spring (8) are installed together in the cavity (404) of the cover plate (4) through the unlocking cover (6).

4. The parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity according to claim 3, characterized in that, The upper end face of the cover plate (4) is provided with a threaded hole b (401) and a cylindrical protrusion (402); wherein, the threaded hole b (401) cooperates with the threaded hole a (101) to realize the connection and fixation between the cover plate (4) and the first model (1); the cylindrical protrusion (402) is used to install and position the second model (2) and constrain the degree of freedom of the second model (2); A recess (404) is provided in the middle of the cover plate (4); a circular through hole a (405) is provided at the center of the bottom of the recess (404); one end of the push rod (7) passes through the inner ring of the spring (8) and is inserted into the circular through hole a (405); the unlocking cover (6) is screwed to the recess (404) to limit the push rod (7) and the spring (8) as a whole in the recess (404); the push rod (7) can move up and down in the recess (404) and compress the spring (8); A circular through hole b (406) is provided on the side of the cavity (404); wherein, when the spring (8) is compressed to the predetermined position, the pin is inserted from the circular through hole b (406) to restrict the spring (8) from popping out, which facilitates the installation of the second model (2) and the second model unlocking device; A circular through hole c (403) is provided on the upper side of the cavity (404); wherein, the circular through hole c (403) is used to hold the pull pin (5) in the locked state.

5. The parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity according to claim 4, characterized in that, The bottom of the second model (2) is provided with a threaded hole c (201) for installing the second model unlocking device and a storage groove (203); wherein, the threaded hole c (201) is located at the center of the bottom of the second model (2), and the two storage grooves (203) are located on both sides of the threaded hole c (201); The second model (2) has a circular blind hole (202) at its bottom; when the second model (2) is placed on the cover plate (4), the cylindrical protrusion (402) is inserted into the circular blind hole (202) to install and position the second model (2) and constrain the degree of freedom of the second model (2).

6. The parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity according to claim 5, characterized in that, The unlocking cover (6) has a thread b (601) and a circular through hole f (605) on its side; wherein, the thread b (601) is used to screw into the cavity (404); the circular through hole f (605) is used to hold the pull pin (5) in the locked state. The bottom side of the unlocking cover (6) is provided with a circular through hole g (602). When the spring (8) is compressed to the predetermined position, the circular through hole g (602) is coaxial with the circular through hole b (406). The pin is inserted from the circular through hole b (406) into the circular through hole g (602) to restrict the spring (8) from popping out, which facilitates the installation of the second model (2) and the unlocking device of the second model. The top of the unlocking cover (6) is provided with a square hole (603), and square grooves (604) are provided on both sides of the square hole (603); the square hole (603) is used to insert the first support rod (14) and the second support rod (15); the square grooves (604) facilitate the operator to rotate the unlocking cover (6) to realize the screw connection between the unlocking cover (6) and the cavity (404).

7. The parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity according to claim 6, characterized in that, The first support rod (14) and the second support rod (15) are two support rods with the same structure, symmetrically arranged along the axis of the unlocking stud (9); wherein: The top of the support rod is provided with a rounded chamfer (1401) to facilitate the rotation of the support rod around the pivot. The top side of the support rod is provided with a pivot mounting hole (1402) for mounting the pivot; The top of the support rod is provided with a torsion spring mounting groove (1403) for mounting a torsion spring; A circular through hole h (1404) is provided on the bottom side of the support rod to lock the pull pin (5) in the locked state. The support rod has a limiting groove (1405) on its side to hold the torsion spring wire, which serves to position and maintain its shape.

8. The parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity according to claim 7, characterized in that, During installation, the cover plate (4) is fixed on the first model (1); the first model unlocking device is installed in the cavity (404) of the cover plate (4); the second model unlocking device is connected and fixed to the second model (2); the first support rod (14) and the second support rod (15) are rotated to the vertical position and inserted into the square hole (603) of the unlocking cover (6). The first support rod (14) and the second support rod (15) are constrained by the square hole (603) and are in a vertical position. The receiving groove (203) is sealed with thin tin foil to maintain its shape. The push rod (7) is pressed down to compress the spring (8) so that the circular through hole at the bottom of the first support rod (14) and the second support rod (15) are aligned with the circular through hole f (605) and the circular through hole c (403). The pull pin (5) is inserted to lock the device in the locked state. When unlocking and separating: the external force acting on the pull pin rope (3) is used to pull out the pull pin (5), the spring (8) releases elastic potential energy, and pushes out the second model (2) to achieve the separation of the two models; after separation, the first support rod (14) and the second support rod (15) lose the constraint of the square hole (603), and rotate to the horizontal position under the action of the first torsion spring (12) and the second torsion spring (13), piercing the thin tin foil and being stored in the storage groove (203) to prevent the second model unlocking device from being exposed.

9. The parallel-stage separation free-flight wind tunnel test device that can provide normal separation velocity according to claim 1, characterized in that, The first model (1) is a scaled-down model of the first stage of the physical aircraft, and the second model (2) is a scaled-down model of the second stage of the physical aircraft. The center of mass of the first model (1) and the second model (2) are located on the same axis. The center of mass of the combined body formed before the separation of the first model (1) and the second model (2) is located inside the first model (1).

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