阅读说明：本技术 一种运动飞机的蒙皮维修方法 (Skin maintenance method for sports aircraft ) 是由 叶杨飞 翟欢乐 李笑瑜 朱莉凯 杨帆 李红燕 刘慎悦 于 2021-06-10 设计创作，主要内容包括：本发明公开了一种运动飞机的蒙皮维修方法。它包括以下步骤：A、以损伤部位为中心,将内外各层都打磨修正成具有圆角过渡的矩形,露出外层的碳纤或玻纤表面一层的边界距裂纹至少30mm形成所需修补部位；B、用砂纸将碳纤或玻纤表面一层打磨成中间略底四周略高的锥形修铺区；C、用溶剂彻底清洗所需修补部位,待溶剂彻底挥发后在该修补部位涂布环氧树脂并铺贴碳纤维补丁。优点是：避免了结构重量发生较大变化带来的影响飞机重心位置的问题。可以形成特定的侧重修补区域,使其修补的强度可以得到有效保证,从而避免了再次损伤的问题。修复简单快捷,省时省力、修补成本很低,可承受规定的强度和刚度,提高经济效率和使用寿命,大幅缩短维修成本。(The invention discloses a skin maintenance method of a moving aircraft. It comprises the following steps: A. polishing the inner layer and the outer layer by taking the damaged part as a center to modify the inner layer and the outer layer into a rectangle with fillet transition, and forming a part to be repaired by enabling the boundary of one layer of the surface of the carbon fiber or the glass fiber exposed out of the outer layer to be at least 30mm away from the crack; B. using sand paper to polish a layer of the surface of the carbon fiber or the glass fiber into a conical repairing area with a middle part and a slightly higher periphery; C. and (3) thoroughly cleaning the required repaired part by using a solvent, coating epoxy resin on the repaired part after the solvent is thoroughly volatilized, and paving a carbon fiber patch. The advantages are that: the problem of influence aircraft centre of gravity position that structural weight takes place great change and brings is avoided. The specific lateral repairing area can be formed, so that the repairing strength can be effectively ensured, and the problem of secondary damage is avoided. The repair is simple and quick, time and labor are saved, the repair cost is low, the specified strength and rigidity can be borne, the economic efficiency is improved, the service life is prolonged, and the maintenance cost is greatly reduced.)

1. A method of repairing a skin of a moving aircraft, comprising the steps of:

A. polishing the inner layer and the outer layer of the skin by taking the damaged part as a center to modify the inner layer and the outer layer of the skin into a rectangle with fillet transition, and enabling the boundary of one layer of the surface of the carbon fiber or the glass fiber exposed out of the outer layer of the skin to be at least 30mm away from the crack to form a part to be repaired;

B. polishing the surface of the skin into a conical repairing area with a middle, a bottom and a periphery which are slightly higher by using sand paper;

C. and (3) thoroughly cleaning the required repaired part by using a solvent, coating epoxy resin on the repaired part after the solvent is thoroughly volatilized, and paving a carbon fiber patch.

2. A method of repairing a skin of a sports aircraft as claimed in claim 1, wherein: and adding glass beads in the coating process of the epoxy resin to enhance the strength and rigidity of the repaired structure.

3. A method of repairing a skin of a moving aircraft as claimed in claim 1 or claim 2, wherein: and after the carbon fiber patch is paved, curing the epoxy resin, polishing and trimming the repaired carbon fiber patch after curing, and finally making a base coat and a finish coat.

4. A method of repairing a skin of a sports aircraft as claimed in claim 3, wherein: the coated epoxy resin is an epoxy resin mixed material which takes epoxy resin as a main raw material and is added with polysulfide rubber and m-xylylenediamine.

5. A method of repairing a skin of a sports aircraft as claimed in claim 4, wherein: the epoxy resin mixed material is also added with glass beads.

6. A method of repairing a skin of a moving aircraft as claimed in claim 1, 2 or 4, wherein: the proportioning method of the epoxy resin mixed material comprises the following steps: the components of the epoxy resin mixed material are added into a container for proportioning, mechanically stirred for 5-15 minutes and then kept stand for 3-10 minutes, and then the repairing operation can be carried out.

7. A method of repairing a skin of a sports aircraft as claimed in claim 5, wherein: and in the step B, if the damaged part comprises the composite material layer of the inner layer, cleaning and polishing the damaged composite material layer into a smooth repair area without cracks.

8. A method of repairing a skin of a sports aircraft as claimed in claim 6, wherein: the required repairing part is the damaged part of the fuselage, the wing or the empennage.

9. A method of repairing a skin of a sports aircraft as claimed in claim 7, wherein: the tail includes a horizontal tail and a vertical tail.

10. A method of repairing a skin of a sports aircraft as claimed in claim 8, wherein: the wing includes a main wing and flaps and ailerons.

Technical Field

The invention relates to an aircraft maintenance technology, in particular to a skin maintenance method of a moving aircraft.

Background

The sports aircraft mostly uses materials such as balsawood and the like as an internal framework, and then uses high-strength composite materials such as carbon fibers or glass fibers as body skins on the surfaces. The skin is often damaged during the use process, particularly the skin of a light-weight sport aircraft is more easily damaged, and the following problems can be generally caused after the skin is damaged: (1) destroying the good aerodynamic performance of the aircraft. (2) The strength, rigidity and durability of the skin at the damaged part are reduced, and the bearing capacity is reduced. (3) The flight safety can be endangered, so whether maintenance is needed to be judged according to damage conditions, in the prior art, the damage conditions mainly include scratch, deformation, crack, broken hole and the like, and the types mainly include two categories: scratch, deformation, crack and hole breaking.

When the skin is slightly blown, pitted or scratched in the scratching and deformation process and at some parts of the skin, the smooth surface of the skin is damaged due to the scratching, the deformation and the like, so that the skin needs to be maintained; the conventional repair method is to supplement resin base on the wound and fill the position.

The cracks and broken holes are divided into small cracks (< 8 cm), medium cracks (8-15 cm) and large cracks (> 15 cm), when the cracks and broken holes meet the small cracks (< 8 cm), the original covering and repairing material is usually cut into pieces and the patch pieces are cleaned, and the patch pieces are adhered to the covering by transparent Pattex contact adhesives; when a medium crack (8-15 cm) occurs, the larger crack must be sewed together with a saddle-shaped needle and a firm thread, and then repaired according to the repairing step of the small crack; when large cracks (> 15 cm) occur, if the wound is too large, the skin needs to be re-produced for replacement of the original skin, which is not in the scope of repair.

For these types of maintenance described above, the specific implementation steps are as follows:

in repair work, the minimum room temperature is guaranteed to be above 20 ℃ to ensure proper hardening of the laminate, since higher temperatures will accelerate the hardening process. Before the maintenance work is started, the wound must be cleaned, the repaired area can be thoroughly cleaned by wiping the wound with a silicon-removing cleaning agent or a grease solvent, and then the damaged area is ground with 60-80 grit paper and the adjacent coating (polyester gel coating) is removed; the fibre layers should be visible 30-50mm around the damaged area, and enough damaged laminate should be left as a mould for repair work if possible; if not possible, wide tapes and sheets (fiberglass, metal sheets, etc.) can be used to form the base for lamination; the sheet must be covered with a release agent, such as a wrapping tape, so that it can be removed after lamination, fig. 1 is a schematic view of the grinding of the laminate.

The next step is a maintenance preparation stage; the fibre fabric is partially cut, the top layer is smaller than the bottom layer, the fibre direction of each layer is the same as that of the bottommost layer, the fabric layer should overlap the repair area by about 30-50mm, the number of layers required depends on the kind of repair material used and the scale of damage, the repair area is then covered with resin, the largest fabric layer is placed in the fibre direction on the bottommost fabric layer, the fabric layer is then fully saturated with a brush, further fabric layers are applied and fully soaked in the same way, no resin can be applied on the last fabric layer, brush application ensures that sufficient resin is absorbed from the lower layer, finally, a PE foil is placed on the repair area and the laminate is allowed to harden, the hardening process can be assisted by uniform heating (about 60 ℃), for example using a heating foil. Once the hardening process has been completed (the upstanding fibres may be broken), the foil is removed and the repair area sanded to ensure a smooth transition of the edges. The repair area should be a few tenths of a millimeter deeper than the surrounding area. If the area is too deep, filling can be carried out, and finally, the repair area is painted to protect the repaired position from being oxidized, and a new laminated board is laid as shown in fig. 2.

Disclosure of Invention

The invention aims to solve the technical problem of providing a skin maintenance method of a sports aircraft, which has the advantages of simple and rapid repair, time and labor saving, low repair cost, proper repair range and small structural weight change after repair, thereby ensuring that the gravity center position of the aircraft is not influenced and the repair strength is ensured.

In order to solve the technical problem, the skin maintenance method of the moving aircraft comprises the following steps:

A. polishing and correcting the inner layer and the outer layer of the skin into a rectangle with a fillet transition by taking the damaged part as a center, and exposing a layer of boundary on the surface of the skin to form a part to be repaired at least 30mm away from the crack;

B. polishing the surface of the skin into a conical repairing area with a middle, a bottom and a periphery which are slightly higher by using sand paper;

C. and (3) thoroughly cleaning the required repaired part by using a solvent, coating epoxy resin on the repaired part after the solvent is thoroughly volatilized, and paving a carbon fiber patch.

And adding glass beads in the coating process of the epoxy resin to enhance the strength and rigidity of the repaired structure.

And after the carbon fiber patch is paved, curing the epoxy resin, polishing and trimming the repaired carbon fiber patch after curing, and finally making a base coat and a finish coat.

The coated epoxy resin is an epoxy resin mixed material which takes epoxy resin as a main raw material and is added with polysulfide rubber and m-xylylenediamine.

The proportioning method of the epoxy resin mixed material comprises the following steps: the components of the epoxy resin mixed material are added into a container for proportioning, mechanically stirred for 5-15 minutes and then kept stand for 3-10 minutes, and then the repairing operation can be carried out.

And in the step B, if the damaged part comprises the composite material layer of the inner layer, cleaning and polishing the damaged composite material layer into a smooth repair area without cracks.

The required repairing part is the damaged part of the fuselage, the wing or the empennage.

The tail includes a horizontal tail and a vertical tail.

The wing includes a main wing and flaps and ailerons.

The invention has the advantages that:

(1) the damage part is polished in a proper area and a proper repair part is set, so that the repair part is ensured to be properly controllable on the basis of effectively ensuring the repair quality, and the problem that the gravity center position of the airplane is influenced due to the fact that the structural weight is greatly changed is solved.

(2) Through the process of polishing the surface of the skin into the conical repairing area with the middle, the bottom and the periphery slightly higher, a specific side repairing area can be formed, the repairing strength can be effectively ensured, and the problem of secondary damage is avoided.

(3) On the basis of adopting the above-mentioned special treatment means, wash the necessary repair position completely with the solvent, after the solvent volatilizes completely directly at the repair position coat epoxy resin and spread the carbon fiber patch to get final product, its repair method is simple and swift, labour saving and time saving, repair cost very low, and because of adopting the special treatment means can further guarantee to coat epoxy resin and spread the firm degree of the carbon fiber patch, further improve the integral strength, make the damaged position repair to bear the intensity and rigidity stipulated, improved economic efficiency and life time at the same time, has shortened the maintenance cost by a wide margin.

Drawings

FIG. 1 is a schematic view of a conventional laminate grinding apparatus;

FIG. 2 is a schematic structural view of a conventional laminate laying;

FIG. 3 is a schematic top view of a skin repair for a sports aircraft according to the present invention;

fig. 4 is a front view of a skin repair of a sports aircraft according to the present invention.

Detailed Description

The skin maintenance method for the sports aircraft does not include the situations that the structural maintenance difficulty is too large due to the damage range of the structural component and the damage range is too large, the component exceeds the economic life, and the airworthiness state needs to be recovered in a short time, and the like.

As shown in the figure, the skin maintenance method of the sports aircraft is suitable for the sports aircraft adopting carbon fiber or glass fiber as the skin, the parts which can be repaired are damaged parts of a fuselage, wings or an empennage, the empennage comprises a horizontal empennage and a vertical empennage, and the horizontal empennage comprises a horizontal stabilizer and an elevator; the vertical tail also comprises a vertical stabilizer and a rudder; the wing comprises a main wing, a flap and an aileron, and as can be seen from the figure, the repair part in the embodiment is composed of a composite board surface 1 at the bottom layer, a primer layer 2 on the composite board surface and a high-strength fiber surface layer 3 on the primer layer, and a crack area 4 is arranged on the high-strength fiber surface layer, and the skin maintenance method of the sports aircraft comprises the following steps:

A. taking a damaged part as a center, polishing and correcting the inner layer and the outer layer (the composite material plate surface 1 and the high-strength fiber surface layer 3) of the skin into a rectangle 5 with fillet transition, wherein the radius of the fillet is larger than 12mm, and the boundary of the exposed high-strength fiber surface layer is at least 25mm away from the crack, so that the part to be repaired is formed, the stress on the damaged part of the skin is reduced for better stress of the structure, and the strength is improved;

B. polishing the surface layer of the high-strength fiber into a conical repairing area with a middle part slightly lower than the periphery by using abrasive paper, and if the damaged part comprises an inner composite material layer (light filling material), cleaning and polishing the damaged composite material layer into a crack-free smooth repairing area;

C. thoroughly cleaning the required repaired part by using a solvent, coating epoxy resin on the repaired part after the solvent is thoroughly volatilized, and paving a carbon fiber patch 6;

D. after the curing, the epoxy resin is cured, and after the curing, the repaired carbon fiber patch is polished and trimmed (the edge is polished to be flat, as shown in fig. 4), and finally, a base coat and a finish coat are made.

Furthermore, the glass beads 7 are added in the coating process of the epoxy resin, and the main function is still to ensure that the stress of the structure is stable so as to enhance the strength and rigidity of the repaired structure.

The epoxy resin coated in this embodiment may be an epoxy resin mixture, the epoxy resin mixture is prepared by using epoxy resin as a main raw material and adding polysulfide rubber, m-xylylenediamine and glass beads, that is, the glass beads are added to the epoxy resin mixture to improve the adhesiveness of the resin, and after the polysulfide rubber and the m-xylylenediamine are added in proportion, the auxiliary material improves the elasticity of the coating, so that the coating can form mechanical properties similar to those of the original skin.

The composite material (containing glass beads) of the room temperature curing epoxy resin is prepared by the following steps:

name of Material	Proportioning parts
		E-51 epoxy resin	100
201 polysulfide rubber	20
		Glass micro-bead (20um)	50
M-xylylenediamine	22

The proportioning process comprises the following steps:

under the room temperature environment, the humidity is within the range of 60-90%, the component materials are slowly added into a container for proportioning, the mechanical stirring is carried out for 10 minutes, the still standing is carried out for 5 minutes, and the epoxy resin for the proportioning and the repairing needs to be used within 30 minutes.