A method for forming a tail boom of a small unmanned helicopter

Abstract

The application discloses a forming method of a small unmanned helicopter vertical tail in the technical field of composite material preparation, and comprises the following steps: preparing a first vertical tail skin, a reinforced skin, a second vertical tail skin, a first vertical tail beam, a second vertical tail beam, a vertical tail adapter, a vertical tail trailing edge foam, a first vertical tail end foam and a second vertical tail end foam; connecting the second vertical tail skin, the first vertical tail beam, the second vertical tail beam, the reinforced skin, the vertical tail trailing edge foam, the first vertical tail end foam and the second vertical tail end foam together to form a vertical tail skin assembly two; connecting the first vertical tail skin and the vertical tail adapter together to form a vertical tail skin assembly one; and fixedly connecting the vertical tail skin assembly one to the upper side of the vertical tail skin assembly two; and the vertical tail with the composite material can be reliably prepared by using the application, and the vertical tail is light in weight and high in strength.

Description

Technical Field

[0001] This invention relates to the field of composite material preparation technology, and in particular to a method for forming the vertical tail of a small unmanned helicopter. Background Technology

[0002] Currently, small unmanned helicopters are widely used in urban traffic monitoring, agricultural and forestry seeding / spraying, and other fields. Composite materials, due to their advantages such as high specific strength, high specific stiffness, designability, and ease of large-area integral molding, have been applied in batches in areas such as wings and fuselage structures of small unmanned helicopters.

[0003] In the current technology, the main material for the vertical tail of small unmanned helicopters is aluminum alloy. The weight of this type of joint is higher than that of composite material joints. In order to give small unmanned helicopters more room for weight reduction, it is urgent to use composite materials to prepare the molding method of the vertical tail of small unmanned helicopters, so as to reduce the weight of the vertical tail while ensuring high strength. Summary of the Invention

[0004] The purpose of this section is to outline some aspects of embodiments of the present invention and to briefly describe some preferred embodiments. Simplifications or omissions may be made in this section, as well as in the abstract and title of this application, to avoid obscuring the purpose of these documents; however, such simplifications or omissions should not be construed as limiting the scope of the invention.

[0005] In view of the problems existing in the above and / or existing helicopter vertical tail manufacturing processes, the present invention is proposed.

[0006] Therefore, the purpose of this invention is to provide a molding method for a small unmanned helicopter vertical tail. This invention can reliably produce a helicopter vertical tail composed entirely of composite materials, which is lightweight and high-strength.

[0007] To solve the above-mentioned technical problems, the present invention provides the following technical solution: a method for forming a vertical tail of a small unmanned helicopter, comprising the following steps:

[0008] S1. Prepare the first tail skin, reinforcing skin, second tail skin, first tail beam, second tail beam, tail adapter, tail trailing edge foam, first tail end foam and second tail end foam.

[0009] S2. Connect the second tail skin, the first tail beam, the second tail beam, the reinforcing skin, the tail trailing edge foam, the first tail end foam, and the second tail end foam together to form the tail skin assembly two.

[0010] S3. Connect the first tail skin and the tail adapter together to form a tail skin assembly.

[0011] S4. Securely connect the tail skin assembly one to the upper side of the tail skin assembly two.

[0012] As a further improvement of the present invention, the step of preparing the first vertical tail skin is as follows:

[0013] Prepare the first tail skin forming mold, which has an upward-facing first laying groove.

[0014] Prepreg is laid in the first laying groove according to the set layer sequence to form the first outer skin;

[0015] Two first honeycomb cores spaced apart in the left-right direction are placed on the upper side of the first outer skin;

[0016] Prepreg is laid in sequence on the upper side of the first honeycomb core and the first outer skin to form the first inner skin;

[0017] Encapsulate and then place in an autoclave for curing;

[0018] Remove the cured part and machine a connection port on the part at a designated position to facilitate connection to the vertical tail adapter.

[0019] As a further improvement of the present invention, the step of preparing the second vertical tail skin is as follows:

[0020] Prepare the second tail skin forming mold, which has an upward-facing second laying groove.

[0021] In the second laying groove, the prepreg is laid in the set layup sequence to form the second outer skin;

[0022] The placement area of ​​the second honeycomb core is located according to the depression of the paving area. Epoxy structural adhesive film is laid in the corresponding area. After the adhesive film is laid, the second honeycomb core is placed according to the laser projection. Epoxy structural adhesive film is also laid on the upper surface of the second honeycomb core.

[0023] Prepreg is laid in a set layering sequence on the upper side of the second honeycomb core and the upper side of the second outer skin to form the second inner skin;

[0024] It is then packaged and placed in an autoclave for curing.

[0025] As a further improvement of the present invention, the step of preparing the first vertical tail beam is as follows:

[0026] Prepare the first beam forming mold, and the upper part of the first beam forming mold is provided with the first laying part;

[0027] Prepreg is laid on the outer edge of the first laying section according to the set layering sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-vacuuming time is not less than 15 minutes.

[0028] Encapsulate and then place in an autoclave for curing;

[0029] Remove the cured part and machine a first mounting groove at the designated position of this part to facilitate the installation of the tail connector.

[0030] As a further improvement of the present invention, the step of preparing the second vertical tail beam is as follows:

[0031] Prepare the second beam forming mold, which includes a base plate and a second laying part fixed on the upper side of the base plate;

[0032] Prepreg is laid along the outer edge of the second paving section in the layup sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-vacuuming time is not less than 15 minutes.

[0033] Encapsulate and then place in an autoclave for curing;

[0034] Remove the cured part and machine a second mounting groove at the designated position of this part to facilitate the installation of the other end of the vertical tail connector.

[0035] As a further improvement of the present invention, the steps for preparing the vertical tail adapter are as follows:

[0036] Prepare the adapter molding mold, which includes an upper insert and a lower insert. The upper insert has at least two positioning countersunk holes at its upward-facing end. The upper insert has several positioning holes that correspond one-to-one with the positioning countersunk holes. The lower insert can be inserted into the positioning pin through the positioning countersunk holes, and the upper insert can be inserted into the corresponding positioning pin through the positioning holes. The bottom surface of the upper insert can fit against the upper surface of the lower insert. The outer perimeter of the contact surface between the lower insert and the upper insert is the R zone, which is a set distance above the contact surface.

[0037] Prepreg is laid on the bottom surface of the upper insert according to the set layup sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-compacting time is not less than 15 minutes.

[0038] Prepreg is laid on the upper part of the lower insert according to the set layup sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-compacting time is not less than 15 minutes.

[0039] Based on the recessed positioning holes and countersunk hole areas of the paving area, divide the prepreg in the areas where the positioning holes and countersunk holes are located on the upper and lower inserts;

[0040] Several locating pins are inserted into the lower insert through the locating countersunk holes. The locating holes of the upper insert are aligned with the locating pins and inserted into the locating pins, so that the upper insert abuts against the lower insert, thus completing the combination of the upper and lower inserts. There is a gap between the bottom of the upper insert and the upper side of the lower insert.

[0041] The carbon wire is made by twisting prepreg into carbon wire, wrapping a layer of adhesive film on the outside of the carbon wire, placing the carbon wire in the core material groove, and pressing the carbon wire with a press. The initial pressure is 8MPa±0.1MPa. The mold is heated to 60℃±5℃ at a heating rate of no more than 1.5℃ / min. Under these conditions, the temperature and pressure are maintained for 0.5h±10min to produce a core material with the same shape as the gap.

[0042] Wrap the core material around the R area once, then vacuum and compact it.

[0043] Several layers of prepreg are laid on the side of the upper and lower inserts after assembly, then sealed and sent to an autoclave for curing.

[0044] During demolding, the upper and lower inserts are separated to complete the demolding of the part.

[0045] As a further improvement of the present invention, after the part is demolded, the prepared thin plate is taken out, the thin plate is glued, and the thin plate is glued to the downward end of the part. The thin plate covers all the hole areas on the part, thus completing the preparation of the vertical tail adapter.

[0046] As a further improvement to the present invention, the preparation step of the skin is strengthened as follows:

[0047] Prepare a reinforced skin forming mold, which includes a support block. A reinforced skin laying part is fixed on the upper side of the support block, and a laying segmentation layer is provided on the reinforced skin laying part.

[0048] Prepreg is laid on the outer edge of the reinforcing skin laying section above the laying segment according to the set lay sequence. Vacuum pre-compacting is performed once every 4 layers, and the pre-vacuuming time is not less than 15 minutes.

[0049] Encapsulate and then place in an autoclave for curing;

[0050] Remove the reinforcing skin molding mold, demold, and obtain the reinforcing skin.

[0051] As a further improvement of the present invention, the steps for preparing the second tail skin assembly are as follows:

[0052] Place the second tail skin on the surface of the second tail skin molding mold, and fix the edges with pressure-sensitive tape to make the second tail skin fit the second tail skin molding mold. Mark the positions of each tail beam and foam on the surface, and use release cloth to protect the non-adhesive areas around the perimeter.

[0053] Apply modeling clay to the upper and outer sides of the second tail skin, and cover the surface with a release film. Place the first and second tail beams on the upper surface of the second tail skin according to the marked positions. Place each foam at the corresponding position on the outer side of the second tail skin. Apply modeling clay to the side where the two foams are joined, the rear side of the foam at the end of the first tail, and the left and right sides of the first and second tail beams respectively, and cover the surface with a release film. After pre-vacuuming the bag, remove the reinforcing skin, each tail beam, and each foam. Depending on the compaction of the modeling clay, apply a layer of adhesive to the bonding surface of the second tail skin. Place each foam and each tail beam according to the marked positions. First, place the first and second tail beams at the corresponding positions on the upper side of the second tail skin. The first tail beam is in front of the second tail beam and joined to it. Place the leading edge foam of the tail beam in front of the first tail beam, and the trailing edge foam in front of the tail beam. Place the second tail beam behind the second tail beam. Based on the compaction of the clay, apply a layer of adhesive to the left and right sides of the leading edge foam of the tail beam, the left and right sides of the trailing edge foam of the tail beam, and the left and right sides of the first and second tail beams. Place the first tail end foam to the left of the leading edge foam of the tail beam, with the front side of the first tail end foam and the front side of the second tail skin flush. Place the reinforcing skin behind the first tail end foam, on the left side of the first and second tail beams, with the rear side of the reinforcing skin and the rear side of the second tail skin flush. Place the second tail end foam to the right of the leading edge foam, the right side of the first tail beam, the right side of the second tail beam, and the right side of the trailing edge foam, with the front and rear sides of the second tail end foam and the second tail skin flush. Pre-extract the bag, unpack and seal it after pre-extraction, transfer the second tail skin forming mold to an autoclave for curing, remove the second tail skin forming mold after curing, demold, and process to form the second tail skin assembly.

[0054] As a further improvement of the present invention, the step of connecting the tail skin assembly one to the tail skin assembly two is as follows:

[0055] When assembling the tail skin assembly, after passing the upper adapter of the tail adapter through the connection port, the upper side of the lower adapter on the lower side of the upper adapter is attached to the lower side of the first tail skin, and the lower adapter is fixedly connected to the first tail skin using fasteners.

[0056] Place the second tail skin assembly on the surface of the second tail skin molding mold, and fix the edges with pressure-sensitive adhesive tape to make the second tail skin fit the second tail skin molding mold. Lay a release film on the bonding surface of the second tail skin assembly, place modeling clay on the release film, place the assembled tail skin assembly on the second tail skin assembly, and use sandbags to compact it for a set time. When the set time is up, remove the tail skin assembly and observe the compaction of the modeling clay on the surface. According to the compaction, apply adhesive to the bonding surface of the second tail skin assembly, gradually lift the release film until the adhesive is applied and the release film is completely removed. Place the tail skin assembly on the corresponding position on the upper surface of the tail skin assembly. The front and rear ends of the lower adapter are respectively inserted into the first tail beam and the second tail beam through the first mounting groove and the second mounting groove.

[0057] Transfer the second tail skin forming mold to the effective temperature range of the autoclave, set the autoclave operating parameters according to the curing process parameters specified in the process document, and complete the curing process.

[0058] Remove the second tail skin forming mold, demold, and obtain the preliminary tail.

[0059] After curing, there is excess glue on the edges of the product. Use sandpaper to polish the surface of the initial tail to obtain the tail.

[0060] Compared with the prior art, the present invention has the following technical effects: Before bonding each component of the vertical tail skin assembly II and before bonding the vertical tail skin assembly I and the vertical tail skin assembly II, the present invention uses the step of placing and compacting modeling clay to verify that each area to be bonded needs to be bonded before bonding, and determines the bonding gap, thereby ensuring reliable bonding; The helicopter vertical tail prepared by the present invention is made entirely of composite materials, providing more space for weight reduction for small unmanned helicopters, while also having high strength; It can be applied to the preparation of helicopter vertical tails. Attached Figure Description

[0061] To more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. Wherein:

[0062] Figure 1 A three-dimensional structural diagram of the vertical tail prepared using the present invention is shown.

[0063] Figure 2 for Figure 1 A magnified view of a portion of point A in the middle.

[0064] Figure 3A three-dimensional structural diagram of the tail fin after concealing the first tail skin.

[0065] Figure 4 for Figure 3 A magnified view of a section at point B.

[0066] Figure 5 This is a three-dimensional structural diagram of the second vertical tail skin component in this invention.

[0067] Figure 6 This is the three-dimensional structure of the tail skin assembly in this invention. Figure 1 .

[0068] Figure 7 This is the three-dimensional structure of the tail skin assembly in this invention. Figure 2 .

[0069] Figure 8 This is a top view of the second vertical tail skin in this invention.

[0070] Figure 9 for Figure 8 The view at CC.

[0071] Figure 10 for Figure 9 A magnified view of a section at point D.

[0072] Figure 11 This is a top view of the first vertical tail skin in this invention.

[0073] Figure 12 for Figure 11 The view at EE.

[0074] Figure 13 for Figure 12 A magnified view of a section at point F.

[0075] Figure 14 This is a three-dimensional structural diagram of the second skin forming mold in this invention.

[0076] Figure 15 This is a three-dimensional structural diagram of the first vertical tail skin forming mold in this invention.

[0077] Figure 16 This is a three-dimensional structural diagram of the second beam forming mold in this invention.

[0078] Figure 17 This is a three-dimensional structural diagram of the first beam forming mold in this invention.

[0079] Figure 18 This is a three-dimensional structural diagram of the reinforcing skin forming mold in this invention.

[0080] Figure 19 This is a three-dimensional structural diagram of the lower insert in this invention.

[0081] Figure 20 This is a three-dimensional structural diagram of the upper insert in this invention.

[0082] Figure 21 This is a three-dimensional structural diagram of the molding die for the vertical tail adapter in this invention.

[0083] Figure 22 This is a structural diagram of the vertical tail adapter prepared using the present invention.

[0084] In the diagram: 100 Vertical tail skin assembly one, 101 Vertical tail adapter, 101-1 Lower adapter, 101-2 Upper adapter, 101-3 R zone, 102 First vertical tail skin, 102-1 First inner skin, 102-2 Second outer skin, 102-3 First honeycomb core; 200 Vertical tail skin assembly two, 201 First vertical tail end foam, 202 Second vertical tail skin, 202-1 Second inner skin, 202-2 Second honeycomb core, 202-3 Second outer skin, 203 Reinforcing skin, 204 First vertical tail beam, 204-1 First mounting groove, 205 Vertical tail leading edge foam, 206 Vertical tail trailing edge foam, 207 Second vertical tail beam, 207-1 Second mounting groove, 208 Second vertical tail end foam. 300 Second tail skin forming mold, 301 Second laying groove, 400 First tail skin forming mold, 401 First laying groove, 500 Second beam forming mold, 501 Base plate, 502 Second laying part, 600 First beam forming mold, 601 First laying part, 700 Reinforcing skin forming mold, 701 Support block, 702 Reinforcing skin laying part, 702-1 Laying dividing layer, 800 Tail adapter forming mold, 801 Lower insert, 801-1 Positioning countersunk hole, 802 Positioning pin, 803 Upper insert, 803-1 Positioning hole, 803-2 Bottom surface. Detailed Implementation

[0085] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings.

[0086] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0087] Secondly, the term "one embodiment" or "embodiment" as used herein refers to a specific feature, structure, or characteristic that may be included in at least one implementation of the present invention. The phrase "in one embodiment" appearing in different places in this specification does not necessarily refer to the same embodiment, nor is it a single or selective embodiment that is mutually exclusive with other embodiments.

[0088] Example 1: Refer to Figures 1 to 18 This is the first embodiment of the present invention, which provides a method for forming a small unmanned helicopter vertical tail. Using the present invention, a small unmanned helicopter vertical tail made of composite material can be reliably prepared, and the prepared product is lightweight and high-strength.

[0089] A method for forming the vertical tail of a small unmanned helicopter includes the following steps:

[0090] S1. Prepare the first tail skin, reinforcing skin, second tail skin, first tail beam, second tail beam, tail adapter, tail trailing edge foam, first tail end foam and second tail end foam.

[0091] S2. Connect the second tail skin, the first tail beam, the second tail beam, the reinforcing skin, the tail trailing edge foam, the first tail end foam, and the second tail end foam together to form the tail skin assembly two.

[0092] S3. Connect the first tail skin and the tail adapter together to form a tail skin assembly.

[0093] S4. Securely connect the tail skin assembly one to the upper side of the tail skin assembly two.

[0094] Before step S1, the process also includes preparing the first tail skin, the reinforcing skin, the second tail skin, the first tail beam, the second tail beam, and the tail adapter. Each foam (preferably polymethacrylimide (PMI) foam) is machined, which is prior art and not an improvement of this application.

[0095] The steps for preparing the first vertical tail skin are as follows:

[0096] Prepare the first tail skin forming mold, which has an upward-facing first laying groove.

[0097] Get carbon fiber unidirectional epoxy prepreg (T700 / E1302), carbon fiber fabric epoxy prepreg (T300P200 / E1302), epoxy structural film (LWF-2A), and aramid paper honeycomb core material (CNC2-1.83-48-3).

[0098] Using the CPD module of Catia software, the shape of each layer of prepreg is simulated and imported into the operating system of the automatic feeder. The prepreg is taken out of the cold storage 6 hours in advance to thaw and left to stand at room temperature until there is no moisture in the packaging bag. The thawed prepreg is placed on the tray of the automatic feeder and each piece is cut according to the program.

[0099] First, lay one layer of [0] direction carbon fiber fabric epoxy prepreg (T300P200 / E1302) in the first laying sink, then lay two layers of [45 / -45] carbon fiber unidirectional epoxy prepreg (T700 / E1302), vacuum pre-compact, the pre-vacuum time is ≥15min, the pre-vacuum time is calculated from the vacuum degree in the vacuum bag ≤-0.095MPa, the bag is removed, and the first outer skin is formed;

[0100] The aramid paper honeycomb core material (CNC2-1.83-48-3) was beveled using a honeycomb bevel template. After beveling, the surface was cleaned and dehumidified in an autoclave at 70±5°C for 1 hour to form the first honeycomb core.

[0101] According to the depression of the paving area, the honeycomb core area is positioned, and epoxy structural adhesive film (LWF-2A) is applied to the corresponding area. After the adhesive film is applied, the first honeycomb core is placed according to the laser projection. The first honeycomb core is placed on the upper side of the first outer skin, and epoxy structural adhesive film (LWF-2A) is also applied to the upper surface of the first honeycomb core.

[0102] Two layers of [45 / -45] carbon fiber unidirectional epoxy prepreg (T700 / E1302) are laid on the upper side of the first honeycomb core and the first outer skin to form the first inner skin;

[0103] The surface is covered with a peelable fabric, a non-porous release film, a breathable felt, and a vacuum bag. After sealing, it is cured in an autoclave (which is a conventional technique).

[0104] Remove the first tail skin forming mold, unpack the bag, demold, and obtain the preliminary first tail skin;

[0105] Remove the cured part and machine a connection port for easy connection of the tail adapter at a set position on the part to obtain the first tail skin.

[0106] The steps for preparing the second vertical tail skin are as follows:

[0107] Prepare the second tail skin forming mold, which has an upward-facing second laying groove.

[0108] Get carbon fiber unidirectional epoxy prepreg (T700 / E1302), carbon fiber fabric epoxy prepreg (T300P200 / E1302), epoxy structural film (LWF-2A), and aramid paper honeycomb core material (CNC2-1.83-48-3).

[0109] Using the CPD module of Catia software, the shape of each layer of prepreg is simulated and imported into the operating system of the automatic feeder. The prepreg is taken out of the cold storage 6 hours in advance to thaw and left to stand at room temperature until there is no moisture in the packaging bag. The thawed prepreg is placed on the tray of the automatic feeder and each piece is cut according to the program.

[0110] First, lay one layer of [0] direction carbon fiber fabric epoxy prepreg (T300P200 / E1302) in the second laying trough, then lay two layers of [45 / -45] carbon fiber unidirectional epoxy prepreg (T700 / E1302), vacuum pre-compact, the pre-vacuum time is ≥15min, the pre-vacuum time is calculated from the vacuum degree in the vacuum bag ≤-0.095MPa, after the pre-vacuum is completed, the bag is removed to form the second outer skin;

[0111] The placement area of ​​the second honeycomb core is located according to the depression of the paving area. Epoxy structural adhesive film is laid in the corresponding area. After the adhesive film is laid, the second honeycomb core is placed according to the laser projection. Epoxy structural adhesive film is also laid on the upper surface of the second honeycomb core.

[0112] The aramid paper honeycomb core material (CNC2-1.83-48-3) was chamfered using a honeycomb chamfering template. After chamfering, the surface was cleaned and dehumidified in an autoclave at 70±5° for 1 hour to obtain the second honeycomb core.

[0113] According to the depression of the paving area, locate the honeycomb core area and lay epoxy structural film (LWF-2A) in the corresponding area. After the film is laid, place the second honeycomb core according to the laser projection, and also lay epoxy structural film (LWF-2A) on the upper surface of the second honeycomb core.

[0114] Two layers of [45 / -45] carbon fiber unidirectional epoxy prepreg (T700 / E1302) are laid sequentially on the upper side of the second honeycomb core and the upper side of the second outer skin to form the second inner skin;

[0115] The surface is covered with a peelable fabric, a non-porous release film, a breathable felt, and a vacuum bag. After sealing, it is sent to an autoclave for curing (this is a conventional technique).

[0116] Remove the second skin forming mold, unpack the bag, demold, and obtain the second tail skin.

[0117] The steps for preparing the first vertical tail beam are as follows:

[0118] Prepare the first beam forming mold, and the upper part of the first beam forming mold is provided with the first laying part;

[0119] Collect carbon fiber unidirectional epoxy prepreg (T700 / E1302).

[0120] Using the CPD module of Catia software, the shape of each layer of prepreg is simulated and imported into the operating system of the automatic feeder. The prepreg is taken out of the cold storage 6 hours in advance to thaw and left to stand at room temperature until there is no moisture in the packaging bag. The thawed prepreg is placed on the tray of the automatic feeder and each piece is cut according to the program.

[0121] Eight layers of carbon fiber unidirectional epoxy prepreg (T700 / E1302) are sequentially laid on the outer edge of the first laying section. The laying sequence is [45 / 0 / -45 / 0 / 0 / -45 / 0 / 45]. Vacuum pre-compacting is performed every four layers. The pre-vacuuming time is not less than 15 minutes. The pre-vacuuming time is calculated from the point when the vacuum degree in the vacuum bag is ≤-0.095MPa.

[0122] The surface is covered with a peelable fabric, a non-porous release film, a breathable felt, and a vacuum bag. After sealing, it is sent to an autoclave for curing (this is a conventional technique).

[0123] Remove the solidified part, and machine a first mounting groove at the designated position of this part to facilitate the installation of the tail connector at one end, thus obtaining the first tail beam.

[0124] The steps for preparing the second vertical tail beam are as follows:

[0125] Prepare the second beam forming mold, which includes a base plate and a second laying part fixed on the upper side of the base plate;

[0126] Collect carbon fiber unidirectional epoxy prepreg (T700 / E1302).

[0127] Using the CPD module of Catia software, the shape of each layer of prepreg is simulated and imported into the operating system of the automatic feeder. The prepreg is taken out of the cold storage 6 hours in advance to thaw and left to stand at room temperature until there is no moisture in the packaging bag. The thawed prepreg is placed on the tray of the automatic feeder and each piece is cut according to the program.

[0128] Eight layers of carbon fiber unidirectional epoxy prepreg (T700 / E1302) are sequentially laid on the outer edge of the first laying section. The laying sequence is [45 / 0 / -45 / 0 / 0 / -45 / 0 / 45]. Vacuum pre-compacting is performed every four layers. The pre-vacuuming time is not less than 15 minutes. The pre-vacuuming time is calculated from the point when the vacuum degree in the vacuum bag is ≤-0.095MPa.

[0129] The surface is covered with a peelable fabric, a non-porous release film, a breathable felt, and a vacuum bag. After sealing, it is sent to an autoclave for curing (this is a conventional technique).

[0130] Remove the solidified part, and machine a second mounting groove at the designated position of this part to facilitate the installation of the other end of the tail connector, thus obtaining the second tail beam.

[0131] The preparation steps for strengthening the skin are as follows:

[0132] Prepare a reinforced skin forming mold, which includes a support block. A reinforced skin laying part is fixed on the upper side of the support block, and a laying segmentation layer is provided on the reinforced skin laying part.

[0133] Collect carbon fiber unidirectional epoxy prepreg (T700 / E1302).

[0134] Using the CPD module of Catia software, the shape of each layer of prepreg is simulated and imported into the operating system of the automatic feeder. The prepreg is taken out of the cold storage 6 hours in advance to thaw and left to stand at room temperature until there is no moisture in the packaging bag. The thawed prepreg is placed on the tray of the automatic feeder and each piece is cut according to the program.

[0135] According to the set layup sequence, lay 6 layers of prepreg on the outer edge of the reinforcing skin laying part on the upper side of the laying segment layer. The layup sequence is [45 / 0 / -45 / -45 / 0 / 45]. Vacuum pre-compact every 4 layers, and the pre-vacuum time is not less than 15 minutes.

[0136] Encapsulate and then place in an autoclave for curing;

[0137] Remove the reinforcing skin molding mold, demold, and obtain the reinforcing skin.

[0138] The steps for preparing the second vertical tail skin assembly are as follows:

[0139] Place the second tail skin on the surface of the second tail skin molding mold, and fix the edges with pressure-sensitive tape to make the second tail skin fit the second tail skin molding mold. Mark the positions of each tail beam and foam on the surface, and use release cloth to protect the non-adhesive areas around the perimeter.

[0140] Apply modeling clay to the upper and outer sides of the second tail skin, and cover the surface with a release film. Place the first and second tail beams on the upper surface of the second tail skin according to the marked positions. Place each foam at the corresponding position on the outer side of the second tail skin. Apply modeling clay to the side where the two foams are joined, the rear side of the foam at the end of the first tail, and the left and right sides of the first and second tail beams respectively, and cover the surface with a release film. After pre-vacuuming the bag, remove the reinforcing skin, each tail beam, and each foam. Depending on the compaction of the modeling clay, apply a layer of adhesive to the bonding surface of the second tail skin. Place each foam and each tail beam according to the marked positions. First, place the first and second tail beams at the corresponding positions on the upper side of the second tail skin. The first tail beam is in front of the second tail beam and joined to it. Place the leading edge foam of the tail beam in front of the first tail beam, and the trailing edge foam in front of the tail beam. Place the second tail beam behind the second tail beam. Based on the compaction of the clay, apply a layer of adhesive to the left and right sides of the leading edge foam of the tail beam, the left and right sides of the trailing edge foam of the tail beam, and the left and right sides of the first and second tail beams. Place the first tail end foam to the left of the leading edge foam of the tail beam, with the front side of the first tail end foam and the front side of the second tail skin flush. Place the reinforcing skin behind the first tail end foam, on the left side of the first and second tail beams, with the rear side of the reinforcing skin and the rear side of the second tail skin flush. Place the second tail end foam to the right of the leading edge foam, the right side of the first tail beam, the right side of the second tail beam, and the right side of the trailing edge foam, with the front and rear sides of the second tail end foam and the second tail skin flush. Pre-extract the bag, unpack and seal it after pre-extraction, transfer the second tail skin forming mold to an autoclave for curing, remove the second tail skin forming mold after curing, demold, and process to form the second tail skin assembly.

[0141] In this embodiment, before bonding each component in the vertical tail skin assembly 2, a step of placing and compacting modeling clay is used to verify that each area to be bonded needs to be bonded before bonding, and to determine the bonding gap, thereby ensuring reliable bonding between the components in the vertical tail skin assembly 1. The vertical tail skin assembly 2 prepared by this invention is made entirely of composite materials, providing more space for weight reduction for small unmanned helicopters, while also having high strength.

[0142] Example 2: As Figure 3 , Figure 4 , Figure 6 , Figure 7 and Figures 19-22 This is the second embodiment of the present invention, which provides a method for forming a small unmanned helicopter vertical tail, which further realizes the preparation of the adapter.

[0143] Specifically, the steps for preparing the vertical tail adapter are as follows:

[0144] Prepare the adapter molding mold, which includes an upper insert and a lower insert. The upper insert has at least two positioning countersunk holes at its upward-facing end. The upper insert has several positioning holes that correspond one-to-one with the positioning countersunk holes. The lower insert can be inserted into the positioning pin through the positioning countersunk holes, and the upper insert can be inserted into the corresponding positioning pin through the positioning holes. The bottom surface of the upper insert can fit against the upper surface of the lower insert. The outer perimeter of the contact surface between the lower insert and the upper insert is the R zone, which is a set distance above the contact surface.

[0145] Prepreg is laid on the bottom surface of the upper insert according to the set layup sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-compacting time is not less than 15 minutes.

[0146] Prepreg is laid on the upper part of the lower insert according to the set layup sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-compacting time is not less than 15 minutes.

[0147] Based on the recessed positioning holes and countersunk hole areas of the paving area, divide the prepreg in the areas where the positioning holes and countersunk holes are located on the upper and lower inserts;

[0148] Several locating pins are inserted into the lower insert through the locating countersunk holes. The locating holes of the upper insert are aligned with the locating pins and inserted into the locating pins, so that the upper insert abuts against the lower insert, thus completing the combination of the upper and lower inserts. There is a gap between the bottom of the upper insert and the upper side of the lower insert.

[0149] Carbon wire is formed by twisting prepreg into carbon wire, and a layer of adhesive film is wrapped around the carbon wire. The carbon wire is placed in the core material groove and pressed down with a press. The initial pressure is 8MPa±0.1MPa. The mold is heated to 60℃±5℃ at a heating rate of no more than 1.5℃ / min. Under these conditions, the temperature and pressure are maintained for 0.5h±10min to produce a core material with the same shape as the gap (the core material preparation technology is existing technology and is not an improvement of this application).

[0150] Wrap the core material around the R area once, then vacuum and compact it.

[0151] Several layers of prepreg are laid on the side of the upper and lower inserts after assembly, then sealed and sent to an autoclave for curing.

[0152] During demolding, the upper and lower inserts are separated to complete the demolding of the part;

[0153] Take out the prepared thin plate, apply adhesive to the thin plate, and attach the thin plate to the downward-facing end of the part. The thin plate covers all the areas where the holes are located on the part, thus completing the preparation of the vertical tail adapter.

[0154] The prepared vertical tail adapter, such as Figure 22 As shown, the adapter includes a lower adapter portion, and an upper adapter portion is fixed on the upper side of the lower adapter portion.

[0155] The steps for connecting tail skin assembly one to tail skin assembly two are as follows:

[0156] When assembling the tail skin assembly, after passing the upper adapter of the tail adapter through the connection port, the upper side of the lower adapter on the lower side of the upper adapter is attached to the lower side of the first tail skin, and the lower adapter is fixedly connected to the first tail skin using fasteners.

[0157] Place the second tail skin assembly on the surface of the second tail skin molding mold, and fix the edges with pressure-sensitive adhesive tape to make the second tail skin fit the second tail skin molding mold. Lay a release film on the bonding surface of the second tail skin assembly, place modeling clay on the release film, place the assembled tail skin assembly on the second tail skin assembly, and use sandbags to compact it for a set time. When the set time is up, remove the tail skin assembly and observe the compaction of the modeling clay on the surface. According to the compaction, apply adhesive to the bonding surface of the second tail skin assembly, gradually lift the release film until the adhesive is applied and the release film is completely removed. Place the tail skin assembly on the corresponding position on the upper surface of the tail skin assembly. The front and rear ends of the lower adapter are respectively inserted into the first tail beam and the second tail beam through the first mounting groove and the second mounting groove.

[0158] Transfer the second tail skin forming mold to the effective temperature range of the autoclave, set the autoclave operating parameters according to the curing process parameters specified in the process document, and complete the curing process.

[0159] Remove the second tail skin forming mold, demold, and obtain the preliminary tail.

[0160] After curing, there is excess glue on the edges of the product. Use sandpaper to polish the surface of the initial tail to obtain the tail.

[0161] In this application, the [0] direction is parallel to the length direction of the skin, the

[90] direction is perpendicular to the [0] direction, the 45° direction is the direction of the center line between [0] and

[90] , the [0] direction is the direction of the center line between 45 and -45°, and the ply direction is defined as conventional technology.

[0162] In this embodiment, before bonding the tail skin assembly 1 and the tail skin assembly 2, a step of placing and compacting modeling clay is used to verify and determine the bonding gap between the tail skin assembly 1 and the tail skin assembly 2. This clarifies the amount of adhesive required for each bonding area before bonding, ensuring reliable bonding between the tail skin assembly 1 and the tail skin assembly 2, and avoiding situations where the bonding is weak or excessive adhesive is used, which could compromise molding accuracy.

[0163] It should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A method for forming the vertical tail of a small unmanned helicopter, characterized in that: Includes the following steps, S1. Prepare the first tail skin, reinforcing skin, second tail skin, first tail beam, second tail beam, tail adapter, tail leading edge foam, tail trailing edge foam, first tail end foam and second tail end foam. S2. Connect the second tail skin, the first tail beam, the second tail beam, the reinforcing skin, the tail leading edge foam, the tail trailing edge foam, the first tail end foam and the second tail end foam together to form the tail skin assembly two. S3. Connect the first tail skin and the tail adapter together to form a tail skin assembly. S4. Fix the tail skin assembly one to the upper side of the tail skin assembly two. The steps for preparing the second vertical tail skin assembly are as follows: Place the second tail skin on the surface of the second tail skin molding mold, and fix the edges with pressure-sensitive tape to make the second tail skin fit the second tail skin molding mold. Mark the positions of each tail beam and foam on the surface, and use release cloth to protect the non-adhesive areas around the perimeter. Apply modeling clay to the upper and outer sides of the second tail cover, and cover the surface with a release film. Place the first and second tail beams on the upper surface of the second tail cover according to the marked positions. Place each foam at the corresponding position on the outer side of the second tail cover. Apply modeling clay to the side where the two foams are joined, the rear side of the foam at the end of the first tail, and the left and right sides of the first and second tail beams respectively, and cover the surface with a release film. After pre-vacuuming the bag, remove the reinforcing cover, each tail beam, and each foam. Apply a layer of adhesive to the bonding surface of the second tail cover according to the compaction of the modeling clay. Place each foam and each tail beam according to the marked positions. First, place the first and second tail beams at the corresponding positions on the upper side of the second tail cover. The first tail beam is in front of the second tail beam and joined to the second tail beam. Place the leading edge foam of the tail beam in front of the first tail beam and the trailing edge foam in front of the tail beam. On the rear side of the second tail beam, according to the compaction of the clay, apply a layer of adhesive to the left and right sides of the leading edge foam of the tail beam, the left and right sides of the trailing edge foam of the tail beam, and the left and right sides of the first and second tail beams. Place the first tail end foam on the left side of the leading edge foam of the tail beam, with the front side of the first tail end foam and the front side of the second tail skin flush. Place the reinforcing skin on the rear side of the first tail end foam, the left side of the first and second tail beams, with the rear side of the reinforcing skin and the rear side of the second tail skin flush. Place the second tail end foam on the right side of the leading edge foam of the tail beam, the right side of the first tail beam, the right side of the second tail beam, and the right side of the trailing edge foam, with the front and rear sides of the second tail end foam and the second tail skin flush. Pre-extract the bag, unpack and seal it after pre-extraction, transfer the second tail skin forming mold to the autoclave for curing, remove the second tail skin forming mold after curing, demold, and process to form the second tail skin component. The steps for preparing the vertical tail adapter are as follows: Prepare the adapter molding mold, which includes an upper insert and a lower insert. The upper insert has at least two positioning countersunk holes at its upward-facing end. The upper insert has several positioning holes that correspond one-to-one with the positioning countersunk holes. The lower insert can be inserted into the positioning pin through the positioning countersunk holes, and the upper insert can be inserted into the corresponding positioning pin through the positioning holes. The bottom surface of the upper insert can fit against the upper surface of the lower insert. The outer perimeter of the contact surface between the lower insert and the upper insert is the R zone, which is a set distance above the contact surface. Prepreg is laid on the bottom surface of the upper insert according to the set layup sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-compacting time is not less than 15 minutes. Prepreg is laid on the upper part of the lower insert according to the set layup sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-compacting time is not less than 15 minutes. Based on the recessed positioning holes and countersunk hole areas of the paving area, divide the prepreg in the areas where the positioning holes and countersunk holes are located on the upper and lower inserts; Several locating pins are inserted into the lower insert through the locating countersunk holes. The locating holes of the upper insert are aligned with the locating pins and inserted into the locating pins, so that the upper insert abuts against the lower insert, thus completing the combination of the upper and lower inserts. There is a gap between the bottom of the upper insert and the upper side of the lower insert. The carbon wire is made by twisting prepreg into carbon wire, wrapping a layer of adhesive film on the outside of the carbon wire, placing the carbon wire in the core material groove of the core material mold, and pressing the carbon wire with a press. The initial pressure is 8MPa±0.1MPa. The mold is heated to 60℃±5℃ at a heating rate of no more than 1.5℃ / min. Under these conditions, the temperature and pressure are maintained for 0.5h±10min to produce a core material with the same shape as the gap. Wrap the core material around the R area once, then vacuum and compact it. Several layers of prepreg are laid on the side of the upper and lower inserts after assembly, then sealed and sent to an autoclave for curing. During demolding, the upper and lower inserts are separated to complete the demolding of the part.

2. The method for forming the vertical tail of a small unmanned helicopter as described in claim 1, characterized in that: The steps for preparing the first vertical tail skin are as follows: Prepare the first tail skin forming mold, which has an upward-facing first laying groove. Prepreg is laid in the first laying groove according to the set layer sequence to form the first outer skin; Two first honeycomb cores spaced apart in the left-right direction are placed on the upper side of the first outer skin; Prepreg is laid in sequence on the upper side of the first honeycomb core and the first outer skin to form the first inner skin; Encapsulate and then place in an autoclave for curing; Remove the cured part and machine a connection port on the part at a designated position to facilitate connection to the tail adapter. The steps for preparing the second vertical tail skin are as follows: Prepare the second tail skin forming mold, which has an upward-facing second laying groove. In the second laying groove, the prepreg is laid in the set layup sequence to form the second outer skin; The placement area of ​​the second honeycomb core is located according to the depression of the paving area. Epoxy structural adhesive film is laid in the corresponding area. After the adhesive film is laid, the second honeycomb core is placed according to the laser projection. Epoxy structural adhesive film is also laid on the upper surface of the second honeycomb core. Prepreg is laid in a set layering sequence on the upper side of the second honeycomb core and the upper side of the second outer skin to form the second inner skin; It is then packaged and placed in an autoclave for curing.

3. The method for forming the vertical tail of a small unmanned helicopter as described in claim 1, characterized in that: The steps for preparing the first vertical tail beam are as follows: Prepare the first beam forming mold, and the upper part of the first beam forming mold is provided with the first laying part; Prepreg is laid on the outer edge of the first laying section according to the set layering sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-vacuuming time is not less than 15 minutes. Encapsulate and then place in an autoclave for curing; Remove the cured part and machine a first mounting groove at the designated position of this part to facilitate the installation of the tail connector.

4. The method for forming the vertical tail of a small unmanned helicopter as described in claim 1, characterized in that: The steps for preparing the second vertical tail beam are as follows: Prepare the second beam forming mold, which includes a base plate and a second laying part fixed on the upper side of the base plate; Prepreg is laid along the outer edge of the second paving section in the layup sequence. Vacuum pre-compacting is performed every 4 layers, and the pre-vacuuming time is not less than 15 minutes. Encapsulate and then place in an autoclave for curing; Remove the cured part and machine a second mounting groove at the designated position of this part to facilitate the installation of the other end of the vertical tail connector.

5. The method for forming the vertical tail of a small unmanned helicopter as described in claim 1, characterized in that: After the part is demolded, the prepared thin plate is taken out, the thin plate is glued, and the thin plate is glued to the downward-facing end of the part. The thin plate covers all the hole areas on the part, thus completing the preparation of the vertical tail adapter.

6. The method for forming the vertical tail of a small unmanned helicopter as described in claim 5, characterized in that: The preparation steps for strengthening the skin are as follows: Prepare a reinforced skin forming mold, which includes a support block. A reinforced skin laying part is fixed on the upper side of the support block, and a laying segmentation layer is provided on the reinforced skin laying part. Prepreg is laid on the outer edge of the reinforcing skin laying section above the laying segment according to the set lay sequence. Vacuum pre-compacting is performed once every 4 layers, and the pre-vacuuming time is not less than 15 minutes. Encapsulate and then place in an autoclave for curing; Remove the reinforcing skin molding mold, demold, and obtain the reinforcing skin.

7. The method for forming the vertical tail of a small unmanned helicopter as described in any one of claims 1 to 6, characterized in that: The steps for connecting tail skin assembly one to tail skin assembly two are as follows: When assembling the tail skin assembly, after passing the upper adapter of the tail adapter through the connection port, the upper side of the lower adapter on the lower side of the upper adapter is attached to the lower side of the first tail skin, and the lower adapter is fixedly connected to the first tail skin using fasteners. Place the second tail skin assembly on the surface of the second tail skin molding mold, and fix the edges with pressure-sensitive adhesive tape to make the second tail skin fit the second tail skin molding mold. Lay a release film on the bonding surface of the second tail skin assembly, place modeling clay on the release film, place the assembled tail skin assembly on the second tail skin assembly, and use sandbags to compact it for a set time. When the set time is up, remove the tail skin assembly and observe the compaction of the modeling clay on the surface. According to the compaction, apply adhesive to the bonding surface of the second tail skin assembly, gradually lift the release film until the adhesive is applied and the release film is completely removed. Place the tail skin assembly on the corresponding position on the upper surface of the tail skin assembly. The front and rear ends of the lower adapter are respectively inserted into the first tail beam and the second tail beam through the first mounting groove and the second mounting groove. Transfer the second tail skin forming mold to the effective temperature range of the autoclave, set the autoclave operating parameters according to the curing process parameters specified in the process document, and complete the curing process. Remove the second tail skin forming mold, demold, and obtain the preliminary tail. After curing, there is excess glue on the edges of the product. Use sandpaper to polish the surface of the initial tail to obtain the tail.

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