Parallel stage separation free flight wind tunnel test device capable of providing normal separation speed

Abstract

The invention discloses a parallel interstage separation free flight wind tunnel test device capable of providing a normal separation speed. The parallel interstage separation free flight wind tunnel test device comprises 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 mounted on the first model, and the first model unlocking device is mounted in a concave cavity of the cover plate; the second model unlocking device is mounted in the second model; the tail end of the pull pin is connected with a pull pin rope; in a locking state, the second model is arranged on the cover plate; the two model unlocking devices are locked through a pull pin; during unlocking and separation, the pull pin is pulled out through external force acting on the pull pin rope, the two model unlocking devices are separated, and the second model is pushed out. According to the method, the two stages of models can be fixed into a whole before separation and can be quickly and effectively separated during separation, the shape is maintained to the greatest extent, and the problem that the normal initial speed capable of being safely separated cannot be provided due to the fact that the parallel interstage separation free flight model is small in longitudinal space is solved.

Description

Technical Field

[0001] The invention belongs to the technical field of model free-flight wind tunnel tests, and in particular relates to a parallel inter-stage separation free-flight wind tunnel test device capable of providing a normal separation velocity. Background Art

[0002] The model free-flying wind tunnel test is a commonly used research method for studying the dynamic aerodynamic characteristics of aircraft, and can also be used for the study of multi-body interference of aircraft. The basic method of the test is to launch the model at high speed against the direction of the airflow after the wind tunnel flow field is stable. The model will fly freely in the wind tunnel for a short period of time to test the safety of multi-stage aircraft separation. At the same time, the model is photographed through the observation window using high-speed photography to obtain the attitude trajectory of the aircraft model in free flight. The dynamic aerodynamic parameters of the aircraft can be obtained after data processing in the later stage.

[0003] The parallel interstage separation free flight wind tunnel test requires that the first model and the second model exist as a rigid whole before separation, and no relative motion degrees of freedom exist. After unlocking is completed, all degrees of freedom of the first model and the second model are released, and each performs independent six-degree-of-freedom motion. However, due to the compression of the aerodynamic force on the head of the parallel interstage separation model, in the absence of a normal separation speed, the parallel interstage separation is prone to collision after the release of the two-stage model's degrees of freedom, and safe separation cannot be achieved. This requires that the separation unlocking test device can meet the following requirements: ensure that the two-stage aircraft model is fixed together as a rigid whole before separation, provide a sufficiently large normal separation speed during separation, and after separation, the two-stage aircraft model each performs independent six-degree-of-freedom motion while avoiding damage to the aircraft model's appearance.

[0004] Since the longitudinal space of the parallel interstage aircraft model is small and there is not enough space for movement, the previous parallel interstage separation free flight wind tunnel test technology cannot provide the two-stage normal separation initial velocity, and collision will occur under many working conditions, and the safe separation of the parallel aircraft cannot be achieved. Therefore, it is necessary to develop a parallel interstage separation free flight wind tunnel test device that can provide the normal separation initial velocity. Summary of the invention

[0005] The technical problem solved by the present invention is: to overcome the shortcomings of the prior art and provide a parallel inter-stage separation free-flight wind tunnel test device that can provide a normal separation velocity, so that the two-stage aircraft model can be fixed as a rigid whole before separation, and a sufficient normal separation initial velocity can be provided during separation. After separation, the two-stage models each perform independent six-degree-of-freedom motion while avoiding damage to the aircraft model shape, so that the parallel aircraft can be safely separated in the wind tunnel and meet the test requirements.

[0006] In order to solve the above technical problems, the present invention discloses a parallel interstage separation free-flying wind tunnel test device capable of providing a normal separation speed, comprising: a first model, a second model, a pin pulling rope, a cover plate, a pin pulling, a first model unlocking device and a second model unlocking device;

[0007] 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 connected and fixed to the second model and installed in the second model; the end of the pull pin is connected to the pull pin rope;

[0008] In the locked state: the second model with the second model unlocking device installed is placed on the cover; the first model unlocking device and the second model unlocking device are locked by pulling out the pins;

[0009] When unlocking and separating: the pin is pulled out by utilizing the external force acting on the pin pulling rope, the first model unlocking device is separated from the second model unlocking device, and the second model is pushed out to realize the separation of the two-stage models.

[0010] In the above-mentioned parallel inter-stage separation free flight wind tunnel test device that can provide normal separation speed, it is characterized in that a cover plate mounting groove for mounting a cover plate is provided on the upper end surface of the first model, and a threaded hole a for connecting and fixing the cover plate is provided on the cover plate mounting groove.

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

[0012] In the above-mentioned parallel interstage separation free-flight wind tunnel test device capable of providing normal separation velocity,

[0013] The upper end surface 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 between the cover plate and the first model; the cylindrical protrusion is used to install and position the second model and constrain the freedom of the second model;

[0014] A concave cavity is provided in the middle of the cover plate; a circular through hole a is provided at the center of the bottom of the concave 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 to the concave cavity to limit the push rod and the spring as a whole in the concave cavity; the push rod can move up and down in the concave cavity and compress the spring;

[0015] A circular through hole b is provided on the side of the concave cavity; wherein, when the spring is compressed to a predetermined position, a pin is inserted from the circular through hole b to restrict the spring from popping out, thereby facilitating the installation of the second model and the second model unlocking device;

[0016] A circular through hole c is arranged on the side surface of the upper end of the cavity; wherein the circular through hole c is used to clamp the pull pin in the locked state.

[0017] In the above-mentioned parallel interstage separation free-flight wind tunnel test device capable of providing normal separation velocity,

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

[0019] A circular blind hole is arranged on the bottom of the second model; 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 interstage separation free-flight wind tunnel test device capable of providing a normal separation speed, the second model unlocking device comprises: an unlocking stud, a first rotating shaft, a second rotating shaft, a first torsion spring, a second torsion spring, a first support rod and a second support rod;

[0021] A thread a is provided on the top side of the unlocking stud for screwing with the threaded hole c; a stud groove is provided on the bottom of the unlocking stud to leave space for the first support rod and the second support rod to rotate; a circular through hole d and a circular through hole e are provided on the side of the stud groove, and the circular through hole d and the circular through hole e are symmetrically arranged along the axis of the unlocking stud for mounting the first rotating shaft and the second rotating shaft;

[0022] The first torsion spring is placed in the groove at the top of the first support rod, and the first rotating shaft passes through the circular through hole d and the first torsion spring, fixing one end of the first support rod in the groove of the stud; the second torsion spring is placed in the groove at the top of the second support rod, and the second rotating shaft passes through the circular through hole e and the second torsion spring, and the other end of the second support rod is fixed in the groove of the stud; wherein, in a natural state, under the action of the first torsion spring and the second torsion spring, the first support rod and the second support rod are in a horizontal state; after applying torque, the first support rod and the second support rod can rotate around the first rotating shaft and the second rotating shaft to a vertical state.

[0023] In the above-mentioned parallel interstage separation free-flight wind tunnel test device capable of providing normal separation velocity,

[0024] The side of the unlocking cover is provided with a thread b and a circular through hole f; wherein the thread b is used for screw connection with the concave cavity; and the circular through hole f is used for clamping 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 a 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 limit the spring from popping out, which facilitates the installation of the second model and the second model unlocking device.

[0026] A square hole is provided on the top of the unlocking cover, and square grooves are provided on both sides of the square hole; wherein the square hole is used to insert the first support rod and the second support rod; the square groove is convenient for the operator to rotate the unlocking cover to realize the screw connection between the unlocking cover and the concave cavity.

[0027] In the above-mentioned parallel interstage separation free-flight wind tunnel test device capable of providing a normal separation velocity, the first support rod and the second support rod are two support rods with the same structure and are symmetrically arranged along the axis of the unlocking stud; wherein:

[0028] The top of the support rod is provided with a circular chamfer to facilitate the rotation of the support rod around the axis;

[0029] A shaft mounting hole is provided on the top side of the support rod for mounting the shaft;

[0030] A torsion spring installation groove is provided on the top of the support rod for installing the torsion spring;

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

[0032] A limited groove is arranged on the side of the support rod to clamp the torsion spring wire and play a role in positioning and shape preservation.

[0033] In the above-mentioned parallel interstage separation free-flight wind tunnel test device capable of providing normal separation velocity,

[0034] During installation, the cover plate is fixed on the first model; the first model unlocking device is installed in the concave cavity of the cover plate; the second model unlocking device is connected and fixed to the second model; the first support rod and the second support rod are rotated to a vertical state and inserted into the square hole of the unlocking cover, the first support rod and the second support rod are constrained by the square hole and are in a vertical state, and the storage groove is sealed with a thin tin foil for shape preservation; the push rod compression spring is pressed downward to align the circular through holes at the bottom of the first support rod and the second support rod with the circular through holes f and c, and the pull pin is inserted to lock, and the device is in a locked state;

[0035] When unlocking and separating: use the external force acting on the pin pulling rope to pull out the pin, the spring releases the elastic potential energy, and pushes out the second model to achieve the separation of the two-stage model; after separation, the first support rod and the second support rod lose the constraint of the square hole, and rotate to a horizontal position under the action of the first torsion spring and the second torsion spring, penetrate the thin tin foil, and are stored in the storage groove to prevent the second model unlocking device from leaking out.

[0036] In the above-mentioned parallel interstage separation free flight wind tunnel test device that can provide normal separation speed, the first model is a scaled model of the first stage of the actual aircraft, and the second model is a scaled model of the second stage of the actual aircraft; the center of mass of the first model and the second model are located on the same axis, and the center of mass of the combination fixedly formed before the first model and the second model are separated is located inside the first model.

[0037] The present invention has the following advantages:

[0038] (1) The present invention discloses a parallel interstage separation free flight wind tunnel test device that can provide a normal separation velocity, which solves the problem that the previous parallel interstage separation free flight test could not provide the normal separation initial velocity. Since the longitudinal space of the parallel aircraft is small and there is not enough actuation space, the existing parallel interstage separation free flight wind tunnel test technology cannot provide the normal separation initial velocity and cannot simulate the separation condition with the normal separation initial velocity. The present 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 models each perform independent six-degree-of-freedom motion, which can effectively simulate the parallel interstage separation condition with the normal separation initial velocity.

[0039] (2) The present invention discloses a parallel interstage separation free flight wind tunnel test device that can provide a normal separation speed. While providing the normal separation initial velocity, it can also restore the model's appearance to the greatest extent. In addition to the need to provide the normal separation initial velocity, the parallel interstage separation free flight also requires that the two-stage aircraft before separation be fixed as a rigid whole, which inevitably leads to the need for some devices of the second model to be connected to the first model. The traditional piston-type separation device can be used to retract the connecting part into the first model to maintain its shape, but because the piston rod cannot be fixedly connected to the second model, the normal separation speed cannot meet the requirements. The present invention adopts a method of cooperating with a support rod and a torsion spring, which can make the connecting part retract into the second model to maintain its shape, while avoiding the piston impact process, thereby ensuring that the normal separation speed meets the requirements.

[0040] (3) The present invention discloses a parallel interstage separation free-fly wind tunnel test device that can provide a normal separation speed. The unlocking separation device remains inside the model after unlocking is completed, and the pulling pin quickly moves away from the test model along with the pulling pin rope, thereby 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) The present invention discloses a parallel interstage separation free-flying wind tunnel test device capable of providing a normal separation velocity, wherein springs of different types can be replaced to change the normal separation velocity. The required elastic potential energy is calculated according to the required normal separation velocity by using the law of conservation of momentum and the law of conservation of energy, thereby selecting the corresponding type of spring. BRIEF DESCRIPTION OF THE DRAWINGS

[0042] Figure 1 It is an axonometric diagram before unlocking and separation of a parallel interstage separation free-flying wind tunnel test device capable of providing a normal separation speed in an embodiment of the present invention;

[0043] Figure 2 It is a full cross-sectional view before unlocking and separation of a parallel interstage separation free-flying wind tunnel test device capable of providing a normal separation speed in an embodiment of the present invention;

[0044] Figure 3 It is a full cross-sectional view of a parallel interstage separation free-flying wind tunnel test device capable of providing a normal separation speed after unlocking and separation in an embodiment of the present invention;

[0045] Figure 4 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 is an exploded schematic diagram of a first model unlocking device and a second model unlocking device in an embodiment of the present invention;

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

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

[0049] Figure 8 It is an exploded schematic diagram of a second model unlocking device in an embodiment of the present invention. DETAILED DESCRIPTION

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

[0051] Reference Figures 1 to 3 In this embodiment, the parallel inter-stage separation free-flying wind tunnel test device that can provide a normal separation speed includes: a first model 1, a second model 2, a pin puller rope 3, a cover plate 4, a pin puller 5, a first model unlocking device and a second model unlocking device. Among them, the cover plate 4 is installed on the first model 1, and the first model unlocking device is installed in the concave 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 pin puller 5 is connected to the pin puller rope 3. In the locked state: the second model 2 equipped 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 pin puller 5. When unlocking and separating: the pin puller 5 is pulled out by the external force acting on the pin puller rope 3, the first model unlocking device is separated from the second model unlocking device, and the second model 2 is pushed out to achieve the separation of the two-stage model.

[0052] In this embodiment, the first model 1 is a scaled model of the first level of the real aircraft, and the second model 2 is a scaled model of the second level of the real aircraft; the center 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 combination fixedly formed before the first model 1 and the second model 2 are separated is located inside the first model 1.

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

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

[0055] In this embodiment, if Figures 2 to 4 As shown, the upper end 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 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 freedom of the second model 2. A concave cavity 404 is provided in the middle of the cover plate 4; a circular through hole a405 is provided at the bottom center of the concave cavity 404; one end of the push rod 7 passes through the inner circle of the spring 8 and is inserted into the circular through hole a405, and the circular through hole a405 can play the role of positioning and constraining the axial movement of the push rod 7; the unlocking cover 6 is screwed with the concave cavity 404 to limit the push rod 7 and the spring 8 as a whole in the concave cavity 404; the push rod 7 can move up and down in the concave 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 a predetermined position, the pin is inserted from the circular through hole b406 to restrict the spring 8 from popping out, thereby facilitating the installation of the second model 2 and the second model unlocking device. A circular through hole c403 is provided on the side of the upper end of the cavity 404; the circular through hole c403 is used to clamp the pull pin 5 in the locked state.

[0056] In this embodiment, if Figure 4 As shown, the bottom of the second model 2 is provided with a threaded hole c201 and a receiving groove 203 for installing the second model unlocking device; the threaded hole c201 is located at the center of the bottom of the second model 2, and the two receiving grooves 203 are respectively 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 freedom of the second model 2.

[0057] In this embodiment, if 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. Among them, the top side of the unlocking stud 9 is provided with a thread a901 for threaded connection with the threaded hole c201; the bottom of the unlocking stud 9 is provided with a stud groove 902 to leave space for the first support rod 14 and the second support rod 15 to rotate; the side of the stud groove 902 is provided with a circular through hole d903 and a circular through hole e904, which are symmetrically arranged along the axis of the unlocking stud 9 for mounting the first rotating shaft 10 and the second rotating shaft 11. The first torsion spring 12 is placed in the groove at the top of the first support rod 14, and 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 groove at the top of the second support rod 15, and the second rotating shaft 11 passes through the circular through hole e904 and the second torsion spring 13, and the other end of the second support rod 15 is fixed 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 the torque is applied, 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, if Figure 6 As shown, the side of the unlocking cover 6 is provided with a thread b601 and a circular through hole f605; the thread b601 is used to be screwed with the concave cavity 404; the circular through hole f605 is used to clamp the pull pin 5 in the locked state. The bottom side of the unlocking cover 6 is provided with 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. The pin is inserted from the circular through hole b406 into the circular through hole g602 to limit the spring 8 from popping out, which is convenient for the installation of the second model 2 and the second model unlocking device. 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 groove 604 facilitates the operator to rotate the unlocking cover 6 to achieve the screw connection between the unlocking cover 6 and the concave cavity 404.

[0059] In this embodiment, if Figures 7-8 As shown, the first support rod 14 and the second support rod 15 are two support rods with the same structure, which are symmetrically arranged along the axis of the unlocking stud 9. Among them: a circular chamfer 1401 is arranged on the top of the support rod to facilitate the support rod to rotate around the rotating shaft; a rotating shaft mounting hole 1402 is arranged on the side of the top of the support rod for mounting the rotating shaft; a torsion spring mounting groove 1403 is arranged on the top of the support rod for mounting the torsion spring; a circular through hole h1404 is arranged on the side of the bottom of the support rod for clamping the pull pin 5 in the locked state; a limiting groove 1405 is arranged on the side of the support rod for clamping the torsion spring wire to play a role in positioning and shape preservation.

[0060] In this embodiment, during installation, the cover plate 4 is fixed on the first model 1; the first model unlocking device is installed in the concave 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, and the storage groove 203 is sealed with a thin tin foil for shape preservation; the push rod 7 is pressed downward 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 hole f605 and the circular through hole c403, and the pull pin 5 is inserted to lock, and the device is in a locked state. When unlocking and separating: the pin 5 is pulled out by the external force acting on the pin pulling rope 3, and the spring 8 releases the elastic potential energy to push out the second model 2, thereby 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 a horizontal position under the action of the first torsion spring 12 and the second torsion spring 13, penetrate the thin tin foil, and are stored in the storage groove 203, so as to avoid leakage of the second model unlocking device, thereby ensuring that the second model 2 is as similar to the aerodynamic shape of the actual aircraft as possible.

[0061] In this embodiment, the required normal separation speed can be changed by replacing springs 8 of different types. The specific method for selecting spring 8 is as follows:

[0062] The normal separation velocity required for the test is v, the mass of the first model as a whole is m1, the mass of the second model as a whole is m2, and the mass of the push rod is ignored. Using the law of conservation of momentum, the normal velocity v1 of the first model as a whole and the normal velocity v2 of the second model as a whole are calculated:

[0063]

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

[0065]

[0066] After actual tests, it was found that in the case of energy loss, the required elastic potential energy of the spring is about twice that of the ideal case. Therefore, the elastic potential energy E that the selected spring needs to release in the concave space of the cover plate is 实际 =2E, the actuating space in the cavity is x, then the required spring stiffness k is:

[0067]

[0068] Then the spring is 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, and can provide sufficient normal separation initial velocity during separation. After separation, the two-stage models each perform independent six-degree-of-freedom motion while avoiding damage to the aircraft model shape, 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 as above in the form of a preferred embodiment, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solution of the present invention by using the methods and technical contents disclosed above without departing from the spirit and scope of the present invention. Therefore, any simple modifications, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention without departing from the content of the technical solution of the present invention shall fall within the protection scope of the technical solution of the present invention.

[0071] The contents not described in detail in the specification of the present invention belong to the common knowledge of professionals in the field.

Claims

1. A parallel interstage separation free-flight wind tunnel test device capable of providing a normal separation velocity, characterized in that: include: A first model (1), a second model (2), a pin pulling rope (3), a cover plate (4), a pin pulling (5), a first model unlocking device and a second model unlocking device; The cover plate (4) is installed on the first model (1), and the first model unlocking device is installed in the concave 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) equipped 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 pulling the pin (5); When unlocking and separating: the pin (5) is pulled out by utilizing the external force acting on the pin pulling rope (3), the first model unlocking device is separated from the second model unlocking device, and the second model (2) is pushed out, thereby realizing the separation of the two-stage models.

2. The parallel interstage separation free-flight wind tunnel test device capable of providing normal separation velocity according to claim 1, characterized in that: The upper end 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 interstage separation free-flight wind tunnel test device capable of providing normal separation velocity according to claim 2, characterized in that: The first model unlocking device comprises: an unlocking cover (6), a push rod (7) and a spring (8); wherein the spring (8) is sleeved on the push rod (7), and the push rod (7) and the spring (8) are integrally installed in a concave cavity (404) of a cover plate (4) through the unlocking cover (6).

4. The parallel interstage separation free-flight wind tunnel test device capable of providing normal separation velocity according to claim 3, characterized in that: The upper end surface 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 achieve 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 concave cavity (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 concave 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 a (405); the unlocking cover (6) is screwed to the concave cavity (404) to limit the push rod (7) and the spring (8) as a whole in the concave cavity (404); the push rod (7) can move up and down in the concave cavity (404) and compress the spring (8); A circular through hole b (406) is provided on the side of the concave cavity (404); when the spring (8) is compressed to a predetermined position, a pin is inserted from the circular through hole b (406) to prevent the spring (8) from popping out, thereby facilitating the installation of the second model (2) and the second model unlocking device; A circular through hole c (403) is provided on the side surface of the upper end of the concave cavity (404); wherein the circular through hole c (403) is used to clamp the pull pin (5) in the locked state.

5. The parallel interstage separation free-flight wind tunnel test device capable of providing 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) and a receiving groove (203) for installing the second model unlocking device; wherein the threaded hole c (201) is located at the center of the bottom of the second model (2), and the two receiving grooves (203) are respectively located on both sides of the threaded hole c (201); 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).

6. The parallel interstage separation free-flight wind tunnel test device capable of providing normal separation velocity according to claim 5, characterized in that: The second model unlocking device comprises: 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 a (901) for being screwed with the threaded hole c (201); the bottom of the unlocking stud (9) is provided with a stud groove (902) for leaving space for the first support rod (14) and the second support rod (15) to rotate; the side of the stud groove (902) is provided with a circular through hole d (903) and a circular through hole e (904), and the circular through hole d (903) and the circular through hole e (904) are symmetrically arranged along the axis of the unlocking stud (9) for mounting the first rotating shaft (10) and the second rotating shaft (11); The first torsion spring (12) is placed in the groove at the top of the first support rod (14), the first rotating shaft (10) passes through the circular through hole d (903) and the first torsion spring (12), and fixes one end of the first support rod (14) in the stud groove (902); the second torsion spring (13) is placed in the groove at the top of the second support rod (15), the second rotating shaft (11) passes through the circular through hole e (904) and the second torsion spring (13), and the other end of the second support rod (15) is fixed in the stud groove (902); wherein, in a 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.

7. The parallel interstage separation free-flight wind tunnel test device capable of providing normal separation velocity according to claim 6, characterized in that: The unlocking cover (6) is provided with a thread b (601) and a circular through hole f (605) on its side; wherein the thread b (601) is used for threading with the concave cavity (404); and the circular through hole f (605) is used for clamping the pull pin (5) in the locked state. A circular through hole g (602) is provided on the bottom side of the unlocking cover (6). When the spring (8) is compressed to a 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), so that the spring (8) is restricted from popping out, thereby facilitating the installation of the second model (2) and the second model unlocking device. A square hole (603) is provided at the top of the unlocking cover (6), and square grooves (604) are provided on both sides of the square hole (603); wherein the square hole (603) is used to insert the first support rod (14) and the second support rod (15); and the square grooves (604) facilitate the operator to rotate the unlocking cover (6) to achieve the screw connection between the unlocking cover (6) and the concave cavity (404).

8. The parallel inter-stage separation free-flight wind tunnel test device capable of providing normal separation velocity according to claim 7, characterized in that: The first support rod (14) and the second support rod (15) are two support rods with the same structure and are symmetrically arranged along the axis of the unlocking stud (9); wherein: The top of the support rod is provided with a circular chamfer (1401) to facilitate the support rod to rotate around the rotation axis; A rotating shaft mounting hole (1402) is provided on the top side of the support rod for mounting the rotating shaft; A torsion spring installation groove (1403) is provided at the top of the support rod for installing the torsion spring; A circular through hole h (1404) is provided on the side surface of the bottom of the support rod for clamping the pull pin (5) in the locked state; A limiting groove (1405) is arranged on the side of the support rod for clamping the torsion spring wire to play the role of positioning and shape preservation.

9. The parallel inter-stage separation free-flight wind tunnel test device capable of providing normal separation velocity according to claim 8, 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 concave 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, and the storage groove (203) is sealed with a thin tin foil for shape preservation; the push rod (7) is pressed downward 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 hole f (605) and the circular through hole c (403); the pull pin (5) is inserted to lock, and the device is in a locked state; When unlocking and separating: the pin (5) is pulled out by using the external force acting on the pin pulling rope (3), and the spring (8) releases the elastic potential energy to push out the second model (2), thereby realizing the separation of the two-stage 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 a horizontal position under the action of the first torsion spring (12) and the second torsion spring (13), penetrate the thin tin foil, and are stored in the storage groove (203), thereby preventing the second model unlocking device from leaking out.

10. The parallel inter-stage separation free-flight wind tunnel test device capable of providing normal separation velocity according to claim 1, characterized in that: The first model (1) is a scaled model of the first stage of the real aircraft, and the second model (2) is a scaled model of the second stage of the real 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 by the first model (1) and the second model (2) before separation is located inside the first model (1).

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