A method of bonding a helicopter tail structure

Abstract

The application provides a bonding method of a helicopter tail structure, which separates a diagonal beam structure or a duct structure according to a process separation surface of a framework and a skin, determines a bonding reference of the structure, and sequentially designs a pre-assembly process and a bonding process according to an inside-out sequence after the reference is determined. All framework parts (which can contain a single-sided skin) are bonded for the first time, the skin is bonded for the second time, the structure is closed, a closed cavity structure is formed, an elastic pin is used for pressing between the bonding surfaces of the bonded parts, the pressing force acts on the bonding surface, and stress is avoided between the tooling and the parts and between the parts and the parts during the pressing process. No stress release occurs during the pressing process, so no bonding deformation occurs after bonding. During the elastic pin pressing process, the pressure and the softening thickness of the adhesive film change, the adaptive continuous pressing is achieved, and the bridging phenomenon is avoided.

Description

Technical Field

[0001] This invention belongs to the field of composite material bonding technology, and specifically relates to a bonding method for a helicopter tail structure. Background Technology

[0002] Because helicopter tail rotors come in various forms, including conventional tail rotors, ducted tail rotors, and tail rotorless tail rotors, helicopter tail structures are typically either conventional tail structures or ducted tail structures, depending on the type of tail rotor.

[0003] The conventional tail section structure consists of a tail beam tube and a diagonal beam structure connected by a T-shaped machined frame. The diagonal beam structure comprises 27 parts, including the front beam, rear beam, support ribs 1-6, end ribs, reinforcing ribs, skin, and tail reduction platform. All parts are made of composite materials and are bonded together using a medium-temperature adhesive film. The diagonal beam structure is the key and challenging aspect of manufacturing the conventional tail section structure.

[0004] The ducted tail section structure consists of a tail beam, duct structure, and vertical stabilizer connected by composite material or T-shaped machined frames. The duct structure typically comprises 30 parts, including a leading edge cone (or front beam), left skin, right skin, lower skin, inner ring, duct diagonal ribs, duct middle ribs, duct rear ribs, upper tail ribs, tail rear edge strips, upper support ribs, lower support ribs, upper sleeve ribs, lower sleeve ribs, sleeve rib reinforcing angle boxes, and sleeve rib reinforcing components. All parts are made of composite materials and are bonded together using a medium-temperature adhesive film bonding process. The duct structure is the key and challenging aspect of manufacturing the ducted tail section structure.

[0005] Both inclined beam and culvert structures are fully composite enclosed structures composed of beams, support ribs, skin, and reinforcing ribs. Traditional culvert bonding and inclined beam component bonding techniques involve pressurizing each bonding surface with an actuator during the bonding process, requiring air supply connections and actuator mounting platforms at each bonding surface. Traditional culvert bonding requires five bonding stages, as follows:

[0006] First bonding: bonding the anterior vertebral body to the inner third rib; Second bonding: bonding the inner ring to the anterior sixth rib; Third bonding: bonding the components after the first bonding, the components after the second bonding, and the posterior sixth rib; Fourth bonding: bonding the components after the third bonding to the left skin; Fifth bonding: bonding the components after the fourth bonding to the right skin.

[0007] The problems existing in the prior art include the following aspects:

[0008] (1) Pressing the adhesive surface with an actuating cylinder requires high precision of the pressurizing device. The pressurizing path of the actuating cylinder and the profile of the pressure strip must be completely consistent with the adhesive surface. This places high demands on the manufacturing of the tooling. Slightly poor precision will cause the pressure strip to fail to press the adhesive surface, instead causing bridging of the adhesive surface and resulting in pressurization failure and product debonding.

[0009] (2) The pressure of the actuator is finally applied to the clamping plate of the fixed rib or other parts. The pressure of the actuator is relatively large. After long-term use, the tooling clamping plate is prone to deformation and displacement under stress. The tooling has a short service life and poor durability, requiring frequent maintenance and repair, and also causing poor product condition consistency.

[0010] (3) Pressurizing the actuator requires the installation of air source connection ports and actuator mounting platforms at each bonding surface. Due to the presence of these devices, the number of parts that can be bonded at one time is limited, requiring at least 5 bonding operations. The large number of bonding operations necessitates a large number of bonding fixtures and extensive coordination between them. Furthermore, the multiple datum conversions during bonding operations lead to significant error and stress accumulation, resulting in poor product accuracy.

[0011] (4) Five bonding processes have a significant impact on product performance; five bonding processes result in a long manufacturing cycle and high manufacturing costs; the tooling is bulky and the operation is cumbersome; and rapid trial production cannot be achieved. Summary of the Invention

[0012] This invention provides a bonding method for helicopter tail structures, aiming to find a new bonding method that achieves high precision, fewer bonding operations, high quality, and simple tooling. The new bonding method is applicable to both the bonding of the inclined beam assembly in conventional tail structures and the bonding of the ducted assembly in ducted tail rotor types.

[0013] This invention provides a method for bonding a helicopter tail section structure, comprising:

[0014] Step 1: Manufacture the beams, skin support ribs, and reinforcing ribs for the helicopter tail structure;

[0015] Step 2: Prepare the components, adhesive film, and tooling required for bonding the inclined beam structure or culvert structure before bonding.

[0016] Step 3: Perform the first adhesive bonding pre-assembly of the inclined beam structure or culvert structure;

[0017] Step 4: Drilling pin holes – Drill φ3.0mm process holes with a spacing of 40-50mm, and clamp them with elastic pins;

[0018] Step 5: Perform pre-bonding treatment on the bonding surfaces;

[0019] Step 6: Laying the adhesive film – Lay the adhesive film on all bonding surfaces of the parts;

[0020] Step 7: Assembly – Assemble and position the parts on the tooling according to the pre-assembly steps, and use elastic pins to connect and pressurize the glued parts;

[0021] Step 8: First bonding and curing – The parts that have been assembled and fixed on the tooling are placed in the curing oven for curing.

[0022] Step 9: Demolding – Remove the elastic pins from the cured parts, remove the tooling clamps and positioning parts, and remove the glued and assembled components from the tooling.

[0023] Step 10: Position and clamp the skin on the tooling using the shape clamp and positioning holes. Observe and measure the fit between each beam, rib and skin and make adjustments to achieve the second adhesive bonding pre-assembly.

[0024] Step 11: Drill the pin holes;

[0025] Step 12: Laying the adhesive film – Lay the adhesive film on all the bonding surfaces of the parts;

[0026] Step 13: Assembly – Assemble and position the parts on the tooling according to the pre-assembly steps, and use elastic pins to connect and pressurize the glued parts.

[0027] Step 14: Second bonding and curing;

[0028] Step 15: Define the positioning holes – After curing, define the positioning holes according to the adhesive clamp for positioning during subsequent assembly;

[0029] Step 16: Demolding – Remove the elastic pins from the cured parts, remove the tooling clamps and positioning parts, and remove the assembled duct assembly from the tooling.

[0030] Step 17: Clean up any excess gelatinous material.

[0031] Optionally, the front and rear beams of the inclined beam structure are manufactured using Invar steel assembly tooling and a vacuum bag-assisted molding process.

[0032] Optionally, the heat shrinkage ratio of the inner ring tooling in the duct structure is determined through iterative experiments.

[0033] Optional, initial adhesive bonding pre-assembly, including:

[0034] S11. Position and clamp the front beam, rear beam, end rib assembly of the inclined beam, tail reduction platform assembly, ribs 2-4 of the inclined beam, tail rotor servo assembly, and right skin of the inclined beam on the adhesive bonding fixture.

[0035] S12. Check the gaps between the rear beam, ribs 2-6 and the outer profile plate; check the gaps between the front and rear beams and ribs 2-6, the tail reduction platform, and the inclined beam end rib assembly; and record the gap values.

[0036] Optional, initial adhesive bonding pre-assembly, including:

[0037] S21. Position the inner ring of the duct structure on the adhesive clamp;

[0038] S22. Position the upper support rib, lower support rib, upper sleeve rib, lower sleeve rib, box-shaped part, reinforcing part, diagonal rib, and middle end rib of the culvert structure on the adhesive bonding fixture.

[0039] S23. Position the front beam, upper rib, rear rib, and lower skin of the culvert structure on the adhesive clamp;

[0040] S24. Position the right skin of the duct on the bonding fixture.

[0041] Optionally, the upper sleeve rib, lower sleeve rib, box-shaped part, reinforcing part, oblique rib, and middle end rib are positioned on the adhesive bonding fixture, using the web surface and the shape of the adhesive bonding surface for positioning;

[0042] The upper and lower support ribs are positioned using the external shape, web surface, positioning holes, and process tail pipe.

[0043] Optionally, pretreatment of the bonding surfaces may be performed, including:

[0044] Use 150-180 grit sandpaper to polish, and then wipe with a wiping paper soaked in solvent.

[0045] Optionally, flexible pins are used to connect and pressurize the bonded parts, including:

[0046] For smooth adhesive surfaces and thin adhesive components, flexible insert-type flexible pins are used.

[0047] For adhesive surfaces with large curvature and thick adhesive layers, spiral pressure type elastic pins are used.

[0048] This invention provides a method for bonding a helicopter tail section structure, which has the following advantages:

[0049] (1) The number of bonding times for the duct structure is reduced from the traditional 5 times to 2 times, which greatly shortens the manufacturing cycle;

[0050] (2) Simplify the structure of the adhesive bonding fixtures for inclined beam structures and culvert structures, and reduce the number of fixtures;

[0051] (3) Simplify the operation process and improve operability;

[0052] (4) Improve product quality and precision;

[0053] (5) Achieve rapid trial production of the tail section structure. Attached Figure Description

[0054] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0055] Figure 1 This is a schematic diagram of the inclined beam structure of the present invention;

[0056] Figure 2 This is a schematic diagram of the duct structure of the present invention;

[0057] Figure 3 This is a schematic diagram of the adhesive bonding and pressure application method of the present invention;

[0058] Explanation of reference numerals in the attached figures:

[0059] 1 - Tail reduction platform components

[0060] 2—First Front Beam

[0061] 3—Right skin of the sloping beam

[0062] 4-2 Rib

[0063] 5 - Rear Beam

[0064] Ribs 6-3

[0065] Ribs 7-4

[0066] Ribs 8-5

[0067] 9—Tail rotor servo assembly

[0068] Ribs 10-6

[0069] 11—Slanted beam end rib assembly;

[0070] 12 - Upper Rib

[0071] 13——Middle rib

[0072] 14 - Second Front Beam

[0073] 15 - Diagonal Rib

[0074] 16 - Inner Ring Road

[0075] 17 - Upper sleeve rib

[0076] 18 - Lower sleeve rib

[0077] 19 - Lower Skin

[0078] 20 - Lower Support Rib

[0079] 21—Left skin of duct

[0080] 22 - Rear Rib

[0081] 23 - Upper Support Rib

[0082] 24 - Adhesive Film

[0083] 25—First Adhesive Joint

[0084] 26—Second adhesive joint

[0085] 27 - Flexible pin. Detailed Implementation

[0086] The adhesive bonding method for the helicopter tail section structure provided by the present invention will be further described below with reference to the accompanying drawings.

[0087] This invention provides a bonding method for a helicopter tail section structure, which involves directly pressing the bonding surface with pressure, and the pressure can be automatically adjusted to adapt to the softening and overflow of the adhesive film during the curing process.

[0088] The new pressurization method has the following effects: 1) After precise positioning, pressure is applied directly between the surfaces to be bonded instead of the pressure being borne by the tooling plate; 2) It reduces the accumulation of errors and stress; 3) It frees up the space available for tooling work and increases the number of parts that can be bonded in a single operation; 4) It improves the quality of bonding.

[0089] This invention employs elastic pins to apply pressure between the bonding surfaces of the bonded parts. The pressure is applied directly to the bonding surfaces, preventing stress from being generated between the tooling and the parts, or between the parts themselves, during the pressure application process. Since there is no stress release during the pressure application process, no bonding deformation occurs after bonding. During the elastic pin pressure application process, the pressure adapts to changes in the softening thickness of the adhesive film, allowing for continuous and adaptive pressure application and preventing bridging.

[0090] This invention achieves the completion of inclined beam or culvert structures with no more than two adhesive bonding processes by rationally designing the tooling structure and bonding sequence.

[0091] The purpose of rationally setting the tooling structure and bonding sequence is: 1) to simplify the tooling structure, simplify the operation process, and reduce the number of tooling; 2) to reduce the number of times the adhesive enters the furnace, so that the bonding of the inclined beam structure or culvert structure can be completed in no more than 2 furnace entries.

[0092] This invention uses a frame-type adhesive bonding fixture. Each clamping plate only positions and initially clamps the parts, without participating in the pressure transmission and bearing of pressure during the pressurization process, thus achieving stress-free connection between the parts and the fixture, and between the parts themselves.

[0093] This invention divides the inclined beam structure or culvert structure into process separation surfaces according to the skeleton and skin, determines the benchmark for structural bonding, and designs the pre-assembly process and bonding process in sequence from the inside to the outside after the benchmark is determined.

[0094] The first bonding is performed on all skeleton parts (including single-sided skin). During this bonding, after determining the reference (usually beams and inner ring parts), each rib and corner piece is assembled in turn. During this process, the space in each link is open and the passage is usually open, and non-destructive testing of the bonding surface can be achieved at the same time.

[0095] The second bonding of the skin seals the structure, forming a closed cavity. It is important to ensure that critical positioning points are established from the initial positioning and that the reference datum is not changed. Alternatively, the positioning holes can be gradually enlarged with each bonding pass to compensate for any discrepancies.

[0096] The specific implementation steps of the adhesive bonding method for the helicopter tail section structure provided by this invention include:

[0097] Step 1: Manufacture beams, skin support ribs, reinforcing ribs, and other parts;

[0098] The first front beam 2 and the rear beam 5 are the benchmarks of the inclined beam structure, and the manufacturing precision of the first front beam 2 and the rear beam 5 is the foundation of the entire inclined beam structure manufacturing. The first front beam 2 and the rear beam 5 are manufactured using Invar steel combined tooling and a vacuum bag-assisted molding process to ensure the precise manufacturing of the first front beam 2 and the rear beam 5.

[0099] The second front beam 14 and the inner ring 16 are the reference points for the duct structure. The inner ring is the central component of the duct structure, and its manufacturing accuracy is the foundation of the entire duct structure manufacturing. The heat shrinkage ratio of the inner ring tooling was determined through iterative experiments to ensure the precise manufacturing of the inner ring parts.

[0100] Step 2: Preparation before bonding - Prepare the components, adhesive film, tooling, etc. required for bonding inclined beam or culvert structures.

[0101] Some small components, such as the tail rotor servo assembly, can be pre-assembled into smaller units to facilitate subsequent operations.

[0102] Step 3: First bonding and pre-assembly

[0103] The first bonding and pre-assembly process of the inclined beam structure:

[0104] S11. Position and clamp the first front beam 2, rear beam 5, inclined beam end rib assembly 11, tail reduction platform assembly 1, inclined beam ribs 2, 3, 6 and 4, tail rotor servo assembly 9 connector, and inclined beam right skin 3 on the adhesive bonding fixture using tooling clamps or positioning parts.

[0105] S12. Check the gaps between the rear beam, rib 4 of No. 2, rib 6 of No. 3, rib 7 of No. 4, rib 8 of No. 5, rib 10 of No. 6 and the outer clamping plate. Check the gaps between the first front beam 2, the rear beam 5 and ribs 2-6, the tail reduction platform assembly, and the inclined beam end rib assembly, and record the gap values.

[0106] First bonding and pre-assembly process of culvert structure:

[0107] S21. Position the inner ring of the duct on the adhesive clamp.

[0108] The inner ring of the duct is positioned on the adhesive bonding fixture using tooling plates or positioning parts. The positioning method of the inner ring is: external positioning + hole positioning.

[0109] S22. Position the upper support rib 23, lower support rib 20, upper sleeve rib 17, lower sleeve rib 18, box-shaped part, reinforcing part, oblique rib 15, and middle end rib 13 on the adhesive bonding fixture using tooling clamps or positioning parts.

[0110] Specifically, the upper sleeve rib 17, lower sleeve rib 18, box-shaped part, reinforcing part, oblique rib, and middle end rib 13 are positioned on the adhesive bonding fixture using tooling plates or positioning parts, and are positioned using the shape of the web surface and the adhesive bonding surface; the upper support rib and lower support rib are positioned using the shape, web surface, positioning hole, and process tail pipe.

[0111] S23. Position the second front beam 14, upper rib 12, rear rib 22, and lower skin 19 on the adhesive bonding fixture using a tooling clamp or positioning piece.

[0112] Specifically, the positioning methods for the front beam, upper rib, and rear rib are: web surface positioning holes + external shape positioning; the positioning method for the lower skin is: external positioning lugs + external shape positioning.

[0113] S24. Position the right skin of the duct (not shown in the figure) on the bonding fixture using a tooling clamp or positioning piece.

[0114] The positioning method for the right skin of the duct is: positioning hole + outline. A margin is left on the skin for localized adjustments during subsequent handover.

[0115] Step 4: Drill the pin holes.

[0116] Specifically, drill φ3.0mm process holes with a spacing of 40-50mm, and clamp them using elastic pins. Thoroughly inspect the gaps between each adhesive surface and record the details.

[0117] For example, the process hole can be borrowed from the rivet hole. It should be noted that the process hole should be smaller than the rivet hole diameter to allow for a certain amount of subsequent riveting compensation and avoid the appearance of a figure-eight hole during riveting.

[0118] Step 5: Perform pre-bonding treatment on the bonding surfaces;

[0119] For example, use 150-180 grit sandpaper for sanding, and then wipe with a wiping paper dipped in solvent to ensure that the surfaces to be bonded are clean and free of contamination.

[0120] Step 6: Laying the adhesive film – Lay the adhesive film 24 on all bonding surfaces of the parts;

[0121] Calculate the required number of adhesive film layers based on the gap value during pre-assembly. Note that the adhesive film thickness should be slightly larger than the gap value to ensure an interference fit during curing and pressurization, thereby ensuring that there are no defects such as insufficient adhesive or debonding on the bonding surface, while also allowing for a certain amount of adhesive overflow.

[0122] Step 7: Assembly – Assemble and position the parts on the tooling using tooling clamps or positioning parts according to the pre-assembly steps, and connect and press the glued parts using elastic pins 27.

[0123] After each component is assembled and positioned on the tooling, check for assembly stress. If the assembly stress is too high, the thickness of the adhesive film needs to be adjusted.

[0124] Example amount, such as Figure 3 As shown, an adhesive film 24 is laid between the first adhesive component 25 and the second adhesive component 26, and the adhesive components are connected and pressurized using elastic pins 27.

[0125] There are two types of flexible pins. The flexible insert type has a smaller clamping force and is suitable for bonding surfaces with gentle curves and thin parts. The spiral pressurized flexible pin is suitable for bonding surfaces with large curvature and thick parts.

[0126] Step 8: First bonding and curing – The parts that have been assembled and fixed on the tooling are placed in the curing oven for curing.

[0127] The curing parameters are matched with the adhesive film used.

[0128] Step 9: Demolding – Remove the elastic pins from the cured parts, remove the tooling clamps and positioning parts, and remove the glued and assembled components from the tooling.

[0129] Step 10: Second pre-assembly - Position and clamp the remaining parts, mainly the left skin of the inclined beam (not shown in the figure) or the left skin of the duct 21, on the tooling using the shape clamp and positioning holes. Observe and measure the fit relationship between each beam, rib and skin and make adjustments.

[0130] Step 11: Drilling pin holes – Drill φ3.0mm process holes on all adhesive surfaces of the pre-assembled parts in their pre-assembled state, with a spacing of 40-50mm between the process holes, and clamp them with elastic pins.

[0131] Process holes can be made using rivet holes. Note that the process hole should be smaller than the rivet hole diameter to allow for subsequent riveting compensation and avoid the appearance of figure-eight holes during riveting.

[0132] Step 12: Laying the adhesive film – Lay the adhesive film on all the bonding surfaces of the parts;

[0133] Calculate the required number of adhesive film layers based on the gap value during pre-assembly. Note that the adhesive film thickness should be slightly larger than the gap value to ensure an interference fit during curing and pressurization, thereby ensuring that there are no defects such as insufficient adhesive or debonding on the bonding surface, while also allowing for a certain amount of adhesive overflow.

[0134] Step 13: Assembly – Assemble and position the parts on the tooling according to the pre-assembly steps, and use elastic pins to connect and pressurize the glued parts.

[0135] After each component is assembled and positioned on the tooling, check for assembly stress. If the assembly stress is too high, the thickness of the adhesive film needs to be adjusted.

[0136] Step 14: Second curing - The parts that have been assembled and fixed on the tooling are placed in the curing oven for curing.

[0137] Step 15: Define the positioning holes – After curing, define the positioning holes according to the adhesive clamp for positioning during subsequent assembly.

[0138] Step 16: Demolding – Remove the elastic pins from the cured parts, remove the tooling clamps and positioning parts, and remove the assembled duct assembly from the tooling.

[0139] Step 17: Cleaning – Remove excess gelatinous tissue.

[0140] The bonding method for the helicopter tail section structure provided by this invention comprises:

[0141] (I) Adhesive bonding pressure method

[0142] Elastic pins are used to apply pressure between the bonding surfaces of the bonded parts. The pressure is applied directly to the bonding surfaces, preventing stress from being generated between the tooling and the parts, or between the parts themselves, during the pressure application process. Since there is no stress release during the pressure application process, no bonding deformation will occur after bonding. During the elastic pin pressure application process, the pressure can be continuously applied adaptively as the adhesive film softens and thickens, preventing bridging.

[0143] (II) Tooling Structure

[0144] Using frame-type adhesive bonding fixtures, the fixture plates or positioning components used for part positioning and clamping do not participate in the pressure transmission and bearing during the pressurization process, thus achieving stress-free interaction between parts and fixtures, and between parts themselves.

[0145] (III) Bonding Sequence

[0146] The inclined beam structure or culvert structure is divided into two bonding processes (i.e. process separation surface) according to the skeleton and skin. The benchmark for structural bonding is determined. After the benchmark is determined, the pre-assembly process and bonding process are designed in sequence from the inside to the outside.

[0147] The first bonding is performed on all skeleton parts (including single-sided skin). During this bonding, after determining the reference (usually beams and inner ring parts), each rib and corner piece is assembled in turn. During this process, the space in each link is open and the passage is usually open, and non-destructive testing of the bonding surface can be achieved at the same time.

[0148] The second bonding of the skin seals the structure, forming a closed cavity. It is important to ensure that critical positioning points are established from the initial positioning and that the reference datum is not changed. Alternatively, the positioning holes can be gradually enlarged with each bonding pass to compensate for any discrepancies.

Claims

1. A method for bonding a helicopter tail section structure, characterized in that, include: Step 1: Manufacture the beams, skin support ribs, and reinforcing ribs for the helicopter tail structure; Step 2: Prepare the components, adhesive film, and tooling required for bonding the inclined beam structure or culvert structure before bonding. Step 3: Perform the first adhesive bonding pre-assembly of the inclined beam structure or culvert structure; Step 4: Drilling pin holes – Drill φ3.0mm process holes with a spacing of 40-50mm, and clamp them with elastic pins; Step 5: Perform pre-bonding treatment on the bonding surfaces; Step 6: Laying the adhesive film – Lay the adhesive film on all bonding surfaces of the parts; Step 7: Assembly – Assemble and position the parts on the tooling according to the pre-assembly steps, and use elastic pins to connect and pressurize the glued parts; Step 8: First bonding and curing – The parts that have been assembled and fixed on the tooling are placed in the curing oven for curing. Step 9: Demolding – Remove the elastic pins from the cured parts, remove the tooling clamps and positioning parts, and remove the glued and assembled components from the tooling. Step 10: Position and clamp the skin on the tooling using the shape clamp and positioning holes. Observe and measure the fit between each beam, rib and skin and make adjustments to achieve the second adhesive bonding pre-assembly. Step 11: Drill the pin holes; Step 12: Laying the adhesive film – Lay the adhesive film on all the bonding surfaces of the parts; Step 13: Assembly – Assemble and position the parts on the tooling according to the pre-assembly steps, and use elastic pins to connect and pressurize the glued parts. Step 14: Second bonding and curing; Step 15: Define the positioning holes – After curing, define the positioning holes according to the adhesive clamp for positioning during subsequent assembly; Step 16: Demolding – Remove the elastic pins from the cured parts, remove the tooling clamps and positioning parts, and remove the assembled duct assembly from the tooling. Step 17: Clean up any excess gelatinous material.

2. The bonding method for the helicopter tail structure according to claim 1, characterized in that, The front and rear beams of the inclined beam structure are manufactured using a combination of Invar steel tooling and a vacuum bag-assisted molding process.

3. The bonding method for the helicopter tail structure according to claim 1, characterized in that, The heat shrinkage ratio of the inner ring tooling in the duct structure was determined through iterative experiments.

4. The bonding method for the helicopter tail structure according to claim 1, characterized in that, The first pre-assembly with adhesive bonding includes: S11. Position and clamp the front beam, rear beam, end rib assembly of the inclined beam, tail reduction platform assembly, ribs 2-4 of the inclined beam, tail rotor servo assembly, and right skin of the inclined beam on the adhesive bonding fixture. S12. Check the gaps between the rear beam, ribs 2-6 and the outer profile plate; check the gaps between the front and rear beams and ribs 2-6, the tail reduction platform, and the inclined beam end rib assembly; and record the gap values.

5. The bonding method for the helicopter tail structure according to claim 1, characterized in that, The first pre-assembly with adhesive bonding includes: S21. Position the inner ring of the duct structure on the adhesive clamp; S22. Position the upper support rib, lower support rib, upper sleeve rib, lower sleeve rib, box-shaped part, reinforcing part, diagonal rib, and middle end rib of the culvert structure on the adhesive bonding fixture. S23. Position the front beam, upper rib, rear rib, and lower skin of the culvert structure on the adhesive clamp; S24. Position the right skin of the duct on the bonding fixture.

6. The bonding method for the helicopter tail structure according to claim 5, characterized in that, The upper sleeve rib, lower sleeve rib, box-shaped part, reinforcing part, oblique rib, and middle end rib are positioned on the adhesive bonding fixture, using the web surface and the shape of the adhesive bonding surface for positioning; The upper and lower support ribs are positioned using the external shape, web surface, positioning holes, and process tail pipe.

7. The bonding method for the helicopter tail structure according to claim 1, characterized in that, Pre-treatment of the bonding surfaces includes: Use 150-180 grit sandpaper to polish, and then wipe with a wiping paper soaked in solvent.

8. The bonding method for the helicopter tail structure according to claim 1, characterized in that, Using flexible pins to connect and pressurize glued parts includes: For smooth adhesive surfaces and thin adhesive components, flexible insert-type flexible pins are used. For adhesive surfaces with large curvature and thick adhesive layers, spiral pressure type elastic pins are used.

Images