A split ventral fin connection structure and connection method

Abstract

The present invention discloses a split ventral fin connection structure and connection method, which divides the ventral fin into two sections, front and rear. The front ventral fin is installed in advance, and the rear ventral fin is not installed until the rudder is installed. Then the rear section of the ventral fin is installed through an external connection. The front ventral fin is integrally formed by molded quartz / phenolic material and ventral fin metal core, which ensures that the surface of the ventral fin structure is resistant to high temperature and that the strength of the ventral fin structure itself meets flight conditions. At the same time, the connection holes on the bottom surface of the ventral fin metal core can ensure the reliability of the connection between the ventral fin structure and the cabin. The rear ventral fin is integrally formed by molded quartz / phenolic material. The front and rear ventral fin sections are connected by molded quartz phenolic bolts, which can be completely completed by operation outside the cabin and is not affected by the space inside the cabin. It avoids the constraints of the product assembly form on the appearance of the ventral fin and the air rudder, improves the aerodynamic and control characteristics of the aircraft, and enhances the overall performance of the aircraft.

Description

Technical Field

[0001] The invention belongs to the field of aircraft design and relates to a split ventral fin connection structure and a connection method. Background Art

[0002] With the advancement of technology, high-speed aircraft are flying at ever-increasing speeds. These high-altitude, high-speed flight conditions place particular demands on the aircraft's aerodynamic shape. To ensure the aircraft's aerodynamic control characteristics, the rudder must have a wedge-shaped design. To reduce heat flux and ablation on the rudder surface, a gap of no more than 6mm exists between the front of the rudder and the ventral fin. The rudder rotates, and the rudder is typically installed after the fixed components on the cabin are installed. However, this rudder shape cannot be installed with the ventral fin already installed. If the rudder is installed first, the cabin will be completely cluttered with equipment, leaving insufficient space for the ventral fin. Furthermore, if the rudder is to be removed, the cabin equipment must be disassembled before the ventral fin can be successfully removed. Summary of the Invention

[0003] The technical problem solved by the present invention is: to overcome the shortcomings of the existing technology, propose a split ventral fin connection structure and connection method, avoid the shape constraints of the ventral fin and air rudder caused by the product assembly form, improve the aerodynamic and control characteristics of the aircraft, and enhance the overall performance of the aircraft.

[0004] The solution of the present invention is:

[0005] A split ventral fin connection structure comprises a front section of the ventral fin and a rear section of the ventral fin; the axial length of the rear section of the ventral fin is less than 1 / 10 of the total length of the ventral fin; the front section of the ventral fin is mounted on a hull; the front section of the ventral fin is made of a molded quartz phenolic material, the core of which is embedded with a metal core, and a connecting section protrudes from the rear end of the front section of the ventral fin; the rear section of the ventral fin is made of a molded quartz phenolic material, and a groove is machined at the front end; when assembled into the overall ventral fin structure, the connecting section protruding from the front section of the ventral fin extends into the groove at the front end of the rear section of the ventral fin, and the connecting section protruding from the front section of the ventral fin is connected to the outer wall of the groove at the front end of the rear section of the ventral fin by bolts.

[0006] Preferably, the bolt is machined from molded quartz phenolic material, and the bolt head and nut are cylindrical, with a diameter twice the diameter of the screw.

[0007] Preferably, the bolt hole in the rear section of the ventral fin is a circular through hole, and the vertical distance between the center of the bolt hole and the protruding connecting section of the front section of the ventral fin is not less than 2 times the diameter of the bolt hole.

[0008] Preferably, the diameter of the bolt hole in the rear section of the ventral fin is the same as the diameter of the bolt head and the nut.

[0009] Preferably, after the screw is tightened, a high-temperature resistant sealant is applied to the surface of the bolt to smooth the surface.

[0010] Preferably, the connecting section is made of molded quartz phenolic material and is integrally formed with the front section of the ventral fin.

[0011] Preferably, the single-side thickness of the molded quartz phenolic material of the front section of the ventral fin is not less than twice the thickness of the metal core, and the single-side thickness of the outer wall of the groove at the front end of the rear section of the ventral fin is not less than the width of the groove.

[0012] The connection method of the split ventral fin connection structure includes:

[0013] (1) Install the front section of the ventral fin on the cabin; the connection method is as follows: the front section of the ventral fin is designed with three connecting bosses connected to the metal core, the connecting bosses are in contact with the metal shell of the cabin, the metal core of the front section of the ventral fin is machined with holes and tapped, screws are passed through the metal shell of the cabin, the connecting bosses are fastened with the corresponding holes and tapped;

[0014] (2) Install the rudder on the cabin and simultaneously install the cabin servo control system inside the cabin;

[0015] (3) The rear segment of the pelvic fin is inserted from bottom to top between the rudder and the front segment of the pelvic fin, and the protruding connecting segment of the front segment of the pelvic fin extends into the groove at the front end of the rear segment of the pelvic fin;

[0016] (4) The protruding connecting section of the front section of the ventral fin is connected to the outer wall of the groove at the front end of the rear section of the ventral fin by multiple bolts.

[0017] Preferably, after the front section of the ventral fin is installed on the cabin, it is no longer necessary to disassemble or assemble the front section of the ventral fin during the entire aircraft assembly process.

[0018] Preferably, the rudder is made of a braided quartz / phenolic material wrapped around a metal rudder core by RTM composite.

[0019] The beneficial effects of the present invention compared with the prior art are:

[0020] The present invention divides the ventral fin into two sections, front and rear. The front section is installed in advance, while the rear section is not installed until the rudder is installed. The rear section is then installed through an external connection. The front section is integrally formed from a molded quartz / phenolic material and a ventral fin metal core. This ensures that the surface of the ventral fin structure is resistant to high temperatures and that the strength of the ventral fin structure itself meets flight conditions. At the same time, the connection holes on the bottom surface of the ventral fin metal core ensure the reliability of the connection between the ventral fin structure and the cabin. The rear section is integrally formed from a molded quartz / phenolic material. The front and rear sections of the ventral fin are connected by molded quartz phenolic bolts, which can be completed entirely outside the cabin without being affected by the space inside the cabin.

[0021] The present invention avoids the shape constraints of the ventral fin and the air rudder caused by the product assembly form through the split ventral fin connection structure, improves the aerodynamic and control characteristics of the aircraft, and enhances the overall performance of the aircraft. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 Schematic diagram of the installation position of the ventral fin and rudder;

[0023] Figure 2 Install top view for ventral fin and rudder;

[0024] Figure 3 side view of the installation for the ventral fin and rudder;

[0025] Figure 4 This is a cross-sectional view of the symmetrical center of the pelvic fin;

[0026] Figure 5 This is the AA section view of the cabin;

[0027] Among them, 1-rudder, 2-rear section of ventral fin, 3-bolt, 4-front section of ventral fin, 5-hull, 6-metal core. DETAILED DESCRIPTION

[0028] The present invention will be further described below in conjunction with the embodiments.

[0029] The present invention divides the ventral fin structure into two sections, front and rear, to facilitate smooth assembly and disassembly of the rudder. The ventral fin structure is subject to heat flux several times greater than that of a larger area. The present invention's connection structure ensures that the ventral fin segments meet both thermal protection requirements and sufficient connection strength.

[0030] The present invention divides the ventral fin into two sections, front and rear. The front section is installed in advance, while the rear section is not installed until the rudder is installed. The rear section is then installed through an external connection. The front section is integrally formed from a molded quartz / phenolic material and a ventral fin metal core. This ensures that the surface of the ventral fin structure is resistant to high temperatures and that the strength of the ventral fin structure itself meets flight conditions. At the same time, the connection holes on the bottom surface of the ventral fin metal core ensure the reliability of the connection between the ventral fin structure and the cabin. The rear section is integrally formed from a molded quartz / phenolic material. The front and rear sections of the ventral fin are connected by molded quartz phenolic bolts, which can be completed entirely outside the cabin without being affected by the space inside the cabin.

[0031] Figures 1 to 5 Shown is a schematic diagram of the split ventral fin connection introduced in the present invention.

[0032] A split ventral fin connection structure comprises a front ventral fin section 4 and a rear ventral fin section 2. The axial length of the rear ventral fin section 2 is less than 1 / 10 of the total ventral fin length. The front ventral fin section 4 is mounted on a hull 5. The front ventral fin section 4 is made of molded quartz phenolic material, with a metal core 6 embedded in the core. A connecting section protrudes from the rear end of the front ventral fin section 4. The connecting section is molded quartz phenolic material and is integrally formed with the front ventral fin section. The rear ventral fin section 2 is also made of molded quartz phenolic material and has a groove machined into the front end. When assembled into the entire ventral fin structure, the protruding connecting section of the front ventral fin section 4 extends into the groove at the front end of the rear ventral fin section 2. The protruding connecting section of the front ventral fin section 4 is connected to the outer wall of the groove at the front end of the rear ventral fin section 2 via a bolt 3. The bolt 3 is machined from the molded quartz phenolic material. The bolt hole in the rear ventral fin section is circular, with the center of the bolt hole at a vertical distance of no less than twice the diameter of the bolt hole from the protruding connecting section of the front ventral fin section. The bolt 3 is machined from molded quartz phenolic material. The bolt head and nut are cylindrical, and the bolt head and nut have the same diameter, which is twice the diameter of the screw.

[0033] The thickness of the molded quartz phenolic material on one side of the front section 4 of the ventral fin is not less than twice the thickness of the metal core, and the thickness of the outer wall of the groove at the front end of the rear section 2 of the ventral fin is not less than the width of the groove.

[0034] The connection method of the split ventral fin connection structure is as follows:

[0035] (1) The ventral fin is made of molded quartz phenolic material, with the core embedded in a metal frame 6. The bolts 3 connecting the front and rear sections of the ventral fin are machined from molded quartz phenolic material. The rudder 1 is made of a braided quartz / phenolic material wrapped around a metal rudder core using RTM (resin transfer molding). The air rudder and ventral fin are both mounted on the hull 5 by mechanical connections.

[0036] (2) The ventral fin is a split structure consisting of two segments (front and back) Figure 3 The middle 4 is the front section of the ventral fin, and the 2 is the rear section of the ventral fin) and are connected by bolts 3.

[0037] (3) After the cabin 5 and ventral fins are produced and delivered, the ventral fin front section 4 is now installed on the cabin. The ventral fin front section 4 contacts the cabin metal shell through three connecting bosses. The connecting holes on the metal core of the ventral fin front section 4 are tapped, and screws are passed through the cabin metal shell and the connecting bosses and connected to the corresponding tapped holes. The screwing process is done inside the cabin, and the ventral fin front section 4 does not need to be disassembled and assembled during the entire aircraft assembly process.

[0038] (4) At this time, the front end of the rudder 1 can be smoothly installed on the cabin because the rear section 2 of the ventral fin has not been installed yet. At the same time, the servo control system in the cabin can be installed in the cabin at the same time.

[0039] (5) After the rudder is installed, the ventral fin rear section 2 is inserted from bottom to top into the predetermined position using the protrusion of the connecting section extending from the ventral fin front section 4 as a guide, and then fastened with four M15 molded quartz / phenolic bolts 3. The spacing between the bolts is about 70 mm. The number of connecting screws can be adjusted as the height of the ventral fin changes.

[0040] (6) Since the bolts are exposed on the outer surface of the aircraft and there should be no obvious step or gap between them and the rear section of the ventral fin, the bolt holes in the rear section of the ventral fin are all Round hole, bolt head and nut are also Circular holes. Two φ3mm blind holes are drilled in the screw head and nut, respectively, allowing for smooth assembly and disassembly using cylindrical pliers of equal diameter. The small surface aperture effectively prevents excessive erosion by high-temperature airflow. After tightening the screw, a high-temperature sealant can be applied to the bolt surface for surface smoothing.

[0041] The present invention aims to circumvent the shape constraints of the ventral fin and the air rudder caused by the product assembly form through a split ventral fin connection structure, thereby improving the aerodynamic and control characteristics of the aircraft and enhancing the overall performance of the aircraft.

[0042] Although the present invention has been disclosed above in terms of preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art may make possible changes and modifications to the technical solutions 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 solutions of the present invention shall fall within the scope of protection of the technical solutions of the present invention.

Claims

1. A method for connecting a split ventral fin connection structure, characterized in that: The split ventral fin connection structure comprises a ventral fin front section (4) and a ventral fin rear section (2); the axial length of the ventral fin rear section (2) is less than 1 / 10 of the total length of the ventral fin; the ventral fin front section (4) is mounted on the cabin (5); the ventral fin front section (4) is made of molded quartz / phenolic material, the core is embedded in the metal core (6), and a connecting section protrudes from the rear end of the ventral fin front section (4); the ventral fin rear section (2) is made of molded quartz / phenolic material, and a groove is machined at the front end; when the ventral fin is assembled into the overall structure, the connecting section protruding from the ventral fin front section (4) extends into the groove at the front end of the ventral fin rear section (2), and the connecting section protruding from the ventral fin front section (4) is connected to the outer wall of the groove at the front end of the ventral fin rear section (2) by a bolt (3); The connection method includes: S1 installs the front section of the ventral fin (4) on the cabin; the connection method is as follows: the front section of the ventral fin (4) is designed with three connecting bosses connected to the metal core, the connecting bosses are in contact with the metal shell of the cabin, the metal core of the front section of the ventral fin (4) is processed with a thread, and the screws pass through the metal shell of the cabin, the connecting bosses and the corresponding hole tappings are fastened; S2 installs the rudder (1) on the cabin and simultaneously installs the cabin servo control system inside the cabin; The rear section of the S3 ventral fin (2) is inserted from bottom to top between the rudder and the front section of the ventral fin (4), and the protruding connecting section of the front section of the ventral fin (4) extends into the groove at the front end of the rear section of the ventral fin (2); The protruding connecting section of the front section (4) of the S4 ventral fin is connected to the outer wall of the front end groove of the rear section (2) of the ventral fin by means of a plurality of bolts (3).

2. The method for connecting a split ventral fin connection structure according to claim 1, characterized in that: The bolt (3) is machined from molded quartz / phenolic material, and the bolt head and nut are cylindrical with a diameter twice the diameter of the screw.

3. The method for connecting a split ventral fin connection structure according to claim 1, wherein: The bolt hole at the rear section of the ventral fin is a circular through hole, and the vertical distance between the center of the bolt hole and the protruding connecting section of the front section of the ventral fin is not less than 2 times the diameter of the bolt hole.

4. The method for connecting a split ventral fin connection structure according to claim 3, wherein: The diameter of the bolt hole at the rear section of the ventral fin is the same as the diameter of the bolt head and nut.

5. The method for connecting a split ventral fin connection structure according to claim 4, characterized in that: After tightening the screws, apply high-temperature resistant sealant on the surface of the bolts to smooth the surface.

6. The method for connecting a split ventral fin connection structure according to claim 4, characterized in that: The connecting section is made of molded quartz / phenolic material and is integrally formed with the front section of the ventral fin.

7. The method for connecting a split ventral fin connection structure according to claim 1, characterized in that: The thickness of the molded quartz / phenolic material on one side of the front section (4) of the ventral fin is not less than twice the thickness of the metal core, and the thickness of the outer wall of the groove at the front end of the rear section (2) of the ventral fin is not less than the width of the groove.

8. The method for connecting a split ventral fin connection structure according to claim 1, characterized in that: After the front section of the ventral fin (4) is installed on the cabin, it is no longer necessary to disassemble the front section of the ventral fin (4) during the entire aircraft assembly process.

9. The method for connecting a split ventral fin connection structure according to claim 1, characterized in that: The rudder (1) is made of a braided quartz / phenolic material wrapped around a metal rudder core by RTM composite.

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