AIRCRAFT BASIC BODY

Description

[0001] The invention relates to an aircraft body made of fiber-reinforced composite material and a method for manufacturing the aircraft body, wherein the aircraft body has a supporting structure designed as an elongated fuselage, wherein a pair of wings consisting of two wings is arranged laterally on the elongated fuselage, wherein the wings are designed such that, during horizontal flight in a horizontal flight direction parallel to a longitudinal axis of the fuselage, a lift force is generated for the aircraft, wherein several receiving devices for receiving propulsion devices are formed on the wings, wherein the aircraft body is formed from an upper shell and a lower shell, wherein the upper shell and the lower shell are connected to each other along a common connecting surface.wherein a tail assembly is arranged at the rear of the fuselage and wherein the tail assembly is formed by a pair of tail surfaces, wherein the guide surfaces of the tail surface pair are oriented in a V-shape towards each other in a horizontal flight direction.

[0002] In the aerospace industry, aircraft components and structural parts are frequently manufactured from fiber-reinforced composites, including fiber-reinforced plastics. These composites consist of fibers embedded in a polymer matrix. For example, carbon fiber reinforced plastics (CFRP) are commonly used in aerospace, where carbon fibers are embedded in a polymer matrix. The matrix serves to bind the fibers and fill the spaces between them. Epoxy resin is frequently used as the matrix material, although thermosets or thermoplastics are also employed. Carbon fiber reinforced plastics are characterized by their low mass and high stiffness.Glass fiber reinforced plastics, in which the fibers embedded in a plastic matrix are made of glass fiber, are also applicable in the field of aviation.

[0003] A component made from carbon fiber reinforced plastics typically exhibits so-called anisotropic properties, meaning that strength and stiffness are significantly higher in the fiber direction than perpendicular to it. To achieve isotropic, i.e., direction-independent, properties, the fiber layers can be oriented and arranged so that they point in several different directions. Furthermore, the desired strength and stiffness in specific directions and component areas can be achieved by predetermining the arrangement and orientation of the fiber layers.

[0004] In aircraft construction, the so-called prepreg manufacturing process is used to produce components from fiber-reinforced plastics or fiber-reinforced plastic composites. In this process, pre-impregnated fabrics or prefabricated textile semi-finished products are soaked in synthetic resins and only thermally treated to a slight degree of hardening, making them manageable layer by layer. Such a sheet-like or layered prepreg semi-finished product typically exhibits a certain degree of adhesion and can therefore be easily arranged in appropriate molds or layer by layer until the desired component shape is achieved. Once the desired layers of the prepreg semi-finished product are arranged, they can be (thermally) cured.To cure these prepreg components, so-called autoclaves are used, in which the prepreg components are treated under overpressure of up to 10 bar and for several hours at temperatures of 120 °C to 200 °C, thereby achieving complete curing of the evacuated prepreg components.

[0005] In aircraft construction, including the production of remotely controlled aircraft such as drones, aircraft bodies are frequently manufactured using a variety of materials and processes. Highly stressed load-bearing structures, such as the elongated fuselage and the wing pairs attached to it, are often made of carbon fiber reinforced plastic, with the prepreg manufacturing process being employed for such large-area aircraft components. Since the prepreg manufacturing process typically involves lining molds with prepreg semi-finished products, usually only semi-shell-shaped parts of an aircraft body can be produced. A typical aircraft body is thus divided into two halves: an upper shell and a lower shell. The upper and lower shells are each manufactured separately in their respective molds.The hardened prepreg components are then shaped by cutting off excess prepreg semi-finished products that protrude when lining the mold, so that the cut prepreg components form the upper shell and the lower shell.

[0006] In order to create a particularly stable connection between the wings and the fuselage, the wings and the upper shell or the lower shell of the fuselage are often already joined in the prepreg manufacturing process by appropriately arranged prepreg semi-finished products to form a prepreg component, so that the curing takes place into a monolithic component.

[0007] Control surface components, such as control surfaces, are also manufactured using the prepreg manufacturing process. However, depending on the shape and arrangement of the individual aircraft or control surface components, the production of a monolithic control surface is not possible. Instead, the aircraft or control surface components, manufactured separately and individually from fiber-reinforced plastics, must subsequently be assembled into an aircraft fuselage or control surface. For this purpose, the control surface components are joined, for example, to the upper shell of the aircraft fuselage or control surface. This assembly is achieved, for example, through a joining process such as gluing, riveting, or screwing. Joined joints or areas created by such joining processes generally exhibit lower strength compared to the strength of the aircraft component itself.Furthermore, such joining areas exhibit a significant mass due to the local accumulation of adhesive, rivets, or screws used to create the respective joint. The use of a large number of joining points and areas thus increases the overall weight of the aircraft, thereby reducing its flight time or range due to the increased power requirements of the propulsion units resulting from the greater mass.

[0008] US patent 7,699,261 B2 discloses an unmanned aerial vehicle (UAV) designed for low-speed, low-altitude, and long-duration operations. The UAV's structure is configured to be essentially insensitive to small arms fire and also exhibits a very low radar cross-section. The aircraft has a modular design, with the main wing and empennage assembly being particularly quick and easy to detach from the fuselage.

[0009] CN 107 738 457 A describes an integrated forming process for the fuselage of an unmanned aerial vehicle (UAV). Carbon fiber prepregs and lightweight foam are used as starting materials, which are applied to the inner walls of a combined double negative mold using an integral layer build-up technique. This is followed by integral curing and forming through an autoclave process.

[0010] US patent 2020 / 0172236 A1 discloses a vertical take-off and landing (VTOL) aircraft. The aircraft comprises a fuselage, a pair of aerodynamic wings, and several pivotable rotors mounted on the fuselage, adjustable between a substantially vertical and a substantially horizontal position. The wings can be modular and detachably connected to the fuselage, allowing for replacement with alternative wing pairs.

[0011] The object of the present invention is therefore considered to be to provide a particularly lightweight and at the same time stable aircraft.

[0012] This problem is solved by manufacturing the upper and lower shells as single pieces, and by positioning the control surfaces directly at the tail and merging into it, so that the empennage is either part of the upper shell or part of the lower shell. This reduces the number of joints, allowing for the production of a particularly lightweight aircraft. Furthermore, the monolithic upper shell provides exceptional stiffness and strength to both the upper shell and the aircraft as a whole. Manufacturing the upper and lower shells as single pieces allows for the creation of aerodynamically shaped outer surfaces in the horizontal flight direction.

[0013] Because the empennage is either an integral part of the upper or lower shell, even a system consisting of several different components can be manufactured as a single piece. The resulting reduction in the number of joints allows for the production of a particularly lightweight aircraft. If the empennage is part of the upper shell, the surfaces of the V-shaped control surfaces face upwards. This allows the empennage to be manufactured as a single piece with the upper shell. If the empennage is part of the lower shell, the surfaces of the control surfaces face downwards, allowing the empennage to be manufactured as a single piece with the lower shell.

[0014] To produce an aircraft body with particularly high strength and low weight, an advantageous embodiment of the invention provides that the upper and lower shells are made of a fiber-reinforced plastic composite. Advantageously, the upper and lower shells are made of a carbon fiber-reinforced plastic, which falls under the category of fiber-reinforced plastic composites. Compared to other fiber-reinforced composite materials, such as glass fiber-reinforced plastics, carbon fiber-reinforced plastics have a particularly low specific weight. Therefore, the upper and / or lower shells made of the carbon fiber-reinforced plastic can be designed to be particularly lightweight, enabling the production of a significantly lighter aircraft body.

[0015] To enable the production of a particularly lightweight aircraft body, an advantageous embodiment of the aircraft body provides that the upper and lower shells are designed and can be connected to each other along the connecting surface in such a way that an internal volume is enclosed by the upper and lower shells, thus creating a hollow aircraft body. Advantageously, the electrical and control-related equipment necessary for the operation of the aircraft can be housed within this hollow aircraft body. In addition to GPS receivers, radio transmitters, radio receivers, cameras, batteries, and drive motors, electrical cables can also be housed within the hollow body and protected from environmental influences such as rain, wind, and impacts.

[0016] The problem initially posed is also solved by a method for manufacturing an aircraft body according to claims 1 to 4, wherein the aircraft body is formed by an upper shell and a lower shell, wherein, in a lamination process, the shape of the upper shell and the lower shell is replicated by forming and arranging one or more layers of a curable material, wherein, in a subsequent curing process, the one or more layers are cured by the application of pressure and temperature, thereby forming the upper shell and the lower shell. Advantageously, the curable material used is prepreg semi-finished products pre-impregnated with an impregnating resin, wherein these prepreg semi-finished products exhibit a certain degree of adhesion and dimensional stability, such that the prepreg component formed from the prepreg semi-finished products can be shaped.

[0017] To enable particularly rapid replication of the aircraft body shape, an advantageous implementation of the invention provides that the upper shell and / or the lower shell are shaped by lining a mold with one or more layers of the curable material. Lining the mold advantageously allows the shape of the upper shell and / or the lower shell to be reproduced. Furthermore, the one or more layers of the curable material can be arranged particularly uniformly next to or on top of each other, enabling the production of a particularly thin-walled upper shell and / or lower shell, and thus a particularly lightweight aircraft body or aircraft.

[0018] In an advantageous embodiment of the invention, the laminate consists of one or more layers of a prepreg semi-finished product. This allows the thickness of the aircraft body to be determined within different areas of the upper and / or lower shell during the lamination process.

[0019] In order to completely and uniformly line all areas of the mold, an advantageous embodiment of the invention provides that the prepreg semi-finished products have a predetermined shape. Larger pieces allow for particularly rapid lining of large areas of the mold. Using smaller pieces, specific areas of the mold can be reinforced with one or more layers of the prepreg semi-finished product, thus achieving the desired stiffness and / or strength of the aircraft body.

[0020] To achieve the desired stiffness and / or strength of the aircraft body, an advantageous embodiment of the method according to the invention provides that the prepreg semi-finished product has different thicknesses within the blank. Furthermore, the prepreg semi-finished products can be prepared in such a way that the lamination process for lining the mold with the prepreg semi-finished products can be carried out particularly quickly, since only one layer of the prepreg semi-finished product is required to achieve the desired stiffness and / or strength of the aircraft body.

[0021] In order to completely line all areas of the mold, an advantageous embodiment of the invention provides that, for defined areas of the upper and lower shells, the mold is lined with pre-cut prepreg blanks during the lamination process. These blanks are precisely cut to fit the respective defined areas. This allows for a particularly uniform lining of curves, bulges, or transitions of the mold with the prepreg blanks. Consequently, a particularly uniform thickness of the aircraft body can be achieved.

[0022] For particularly uniform curing of the curable material, an advantageous embodiment of the invention provides for the curing process to be carried out in an autoclave. However, according to the invention, the curing process is also possible and provided for in a conventional oven, thus requiring less effort for the preparation of the prepreg semi-finished products placed in the mold. Furthermore, curing can also be carried out within heated molds. This allows for particularly fast and uniform curing of the curable material.

[0023] For a particularly simple connection between the upper and lower shells, an advantageous embodiment of the invention provides that the upper and lower shells are joined together in a joining process following the curing process. Advantageously, the upper and lower shells are joined by adhesive bonding, resulting in a continuous and uniform bonding surface. This allows for a particularly uniform stiffness and / or strength of the aircraft body.

[0024] To simplify the production of a monolithic component, an advantageous implementation of the invention provides that the upper and lower shells are joined in an uncured state in a joining process preceding the curing process. This joining can be achieved by thermally softening the curable material in the desired connection areas of the upper and / or lower shells, bringing the softened connection areas into contact with each other so that they bond or at least form a certain adhesive bond. In the subsequent curing process, a solid, cured bond between the upper and lower shells is created.

[0025] In an advantageous embodiment of the method according to the invention, it is provided that during the lamination process, the one or more layers of the curable material of the upper shell and the lower shell can be brought into contact with each other within an overlap area, so that during the curing process the upper shell and the lower shell bond to form a monolithic aircraft body. Within the overlap area, an overlap of the one or more layers of the curable material of the upper shell with the one or more layers of the curable material of the lower shell is achieved solely by a corresponding arrangement and orientation of the curable material. No upstream or downstream joining process is required. Furthermore, no joining points are necessary for connecting the upper shell and the lower shell, thus enabling the production of a particularly lightweight aircraft body.

[0026] Further advantageous embodiments of the invention are explained with reference to exemplary embodiments illustrated in the drawings. These show: Figure 1 a schematic representation of the aircraft body in a perspective view, Figure 2 a schematic representation of the aircraft body consisting of the upper and lower shells in a sectional view along the in Figure 1 shown section line AA, Figure 3 a schematic representation of a section of the tool mold for manufacturing the upper shell with prepreg semi-finished products inserted into the tool mold in the area of ​​the tail assembly of the aircraft body in a top view and Figure 4 A schematic representation of the tool mold with prepreg semi-finished products inserted into the tool mold for the production of the upper shell in the area of ​​the tail assembly of the aircraft fuselage in a sectional view along the Figure 3Section line BB shown.

[0027] In Figure 1 Figure 1 shows a schematic representation of the aircraft body 1 of the aircraft 2 in a perspective view. The aircraft body 1 is made of carbon fiber reinforced plastic. The aircraft body 1 has a supporting structure designed as an elongated fuselage 3. A pair of wings, consisting of two wings 4, is arranged laterally on the elongated fuselage 3. The wings 4 are designed such that, during horizontal flight in a horizontal flight direction parallel to a longitudinal axis 5 of the fuselage 3, a lift force is generated for the aircraft 2. Several mounting devices 6 for receiving [unclear text] are located on the wings 4. Figure 1 propulsion systems not shown. The aircraft body 1 consists of an upper shell 7 and a [missing information] Figure 1The lower shell 8 (not shown) is formed. The upper shell 7 and the lower shell 8 are connected along a Figure 1 The two sections are connected by a common connecting surface 9 (not shown). A tail assembly 11 is located at the rear 10 of the fuselage 3, formed by a pair of tail surfaces 12 consisting of guide vanes 13. The guide vanes 13 of the tail surface pair 12 are oriented in a V-shape relative to each other and are part of the upper shell 7.

[0028] In Figure 2 is a schematic representation of the aircraft body 1, consisting of the upper shell 7 and lower shell 8, in a sectional view along the in Figure 1The section line AA is shown. The upper shell 7 and the lower shell 8 are connected to each other along the common connecting surface 9. The upper shell 7 and the lower shell 8 are designed and connected to each other along the connecting surface 9 such that an internal volume 14 is enclosed by the upper shell 7 and the lower shell 8, so that the aircraft body 1 is designed as a hollow body. The guide surfaces 13 of the tail wing pair 12 are oriented in a V-shape to each other and are part of the upper shell 7. In a joining process, the upper shell 7 and the lower shell 8 are joined to each other by means of a joining process. Advantageously, the upper shell 7 and the lower shell 8 are joined to each other by means of adhesive bonding, which creates a continuous and uniform connecting surface 9.

[0029] In Figure 3Figure 1 shows a schematic top view of a section of a mold 15 for manufacturing the upper shell 7, with prepreg semi-finished products 16 inserted into the mold 15 in the area of ​​the tail assembly 11 of the aircraft body 1. By lining the mold 15, the shape of the upper shell 7 and / or the lower shell 8 can be advantageously reproduced. The one or more layers of prepreg semi-finished products 16 can be arranged particularly uniformly next to or on top of each other and adapted to the mold very easily. The prepreg semi-finished products 16 consist of several different predefined blanks 17. Using large blanks 17, large areas of the mold 15 can be lined particularly quickly, and using small blanks 17, specific areas of the mold 15 can be lined with particular precision.

[0030] In Figure 4Figure 1 is a schematic representation of the tool mold 15 for manufacturing the upper shell 7 with prepreg semi-finished products 16 inserted into the tool mold 15 in the area of ​​the tail assembly 11 of the aircraft body 1 in a sectional view along the Figure 3 The section line BB is shown. The shape of the tail assembly 11 or the guide surfaces 13 is replicated by lining the tool mold 15. To achieve the desired stiffness and / or strength of the aircraft body 1, the invention provides that the prepreg semi-finished product 16 has different thicknesses within the blank.

Claims

1. Base body (1) of an aerial vehicle of an aerial vehicle made of fiber-reinforced composite material, wherein the base body (1) of the aerial vehicle comprises a supporting structure configured as an elongated fuselage (3), wherein a wing pair consisting of two wings is arranged laterally on the elongated fuselage (3), wherein the wings (4) are configured such that, during a horizontal flight movement in a horizontal flight direction parallel to a longitudinal axis (5) of the fuselage (3), a lift force for the aerial vehicle (2) is generated, wherein a plurality of receiving devices for receiving drive devices are formed on the wings, wherein the base body (1) of an aerial vehicle is formed from an upper shell (7) and a lower shell (8), wherein the upper shell (7) and the lower shell (8) are connected to one another along a common connecting surface (9), wherein an empennage (11) is arranged at a tail (10) of the fuselage (3), and wherein the empennage (11) is formed by an empennage surface pair (12), wherein stabilizing surfaces (13) of the empennage surface pair are aligned in a V-shape relative to one another in a horizontal flight direction, wherein the upper shell (7) and the lower shell (8) are each manufactured in one piece, characterized in that the stabilizing surfaces (13) are arranged directly on the tail (10) and merge into the tail (10), such that the empennage (11) constitutes either a component of the upper shell (7) or a component of the lower shell (8).

2. Base body (1) of an aerial vehicle according to claim 1, characterized in that the upper shell (7) and the lower shell (8) are made of a fiber-plastic composite.

3. Base body (1) of an aerial vehicle according to any one of the preceding claims, characterized in that the upper shell (7) and the lower shell (8) are configured such and can be brought into connection with one another along the connecting surface (9) such that an internal volume (14) is enclosed by the upper shell (7) and by the lower shell (8), such that the base body (1) of an aerial vehicle is configured as a hollow body.

4. Method for producing an base body (1) of an aerial vehicle of an aerial vehicle (2) according to claims 1 to 3, wherein the body of the aerial vehicle is formed by an upper shell (7) and a lower shell (8), wherein, in a laminating process, a shape of the upper shell (7) and of the lower shell (8) is reproduced by shaping and arranging one or more layers of a curable material, wherein, in a subsequent curing process, the one or the plurality of layers are cured by application of pressure and temperature, whereby the upper shell (7) and the lower shell (8) are formed.

5. Method according to claim 4, characterized in that the shaping of the upper shell (7) and / or of the lower shell (8) is carried out by lining a tool mold (15) with one or more layers of the curable material.

6. Method according to any one of claims 4 or 5, characterized in that the laminate consists of one or more layers of a prepreg semi-finished product (16).

7. Method according to claim 6, characterized in that the prepreg semi-finished products (16) have a predetermined cut-to-size blank (17).

8. Method according to claim 7, characterized in that the prepreg semi-finished product (16) has different thicknesses within the cut-to-size blank (17).

9. Method according to any one of claims 7 or 8, characterized in that, for defined regions of the upper shell (7) and of the lower shell (8), the tool mold (15) is lined in the laminating process with the laminate by means of predetermined cut-to-size blanks (17) of the prepreg semi-finished product (16) fitting the respective defined regions.

10. Method according to any one of claims 4 to 9, characterized in that the curing process is carried out in an autoclave.

11. Method according to any one of claims 4 to 10, characterized in that the upper shell (7) and the lower shell (8) are connected to one another by means of a joining method in a joining process downstream of the curing process.

12. Method according to any one of claims 4 to 10, characterized in that the upper shell (7) and the lower shell (8) are joined together in an uncured state in a joining process upstream of the curing process.

13. Method according to any one of claims 4 to 10, characterized in that, in the laminating process, the one or more layers of the curable material of the upper shell (7) and of the lower shell (8) can be brought into contact with one another within an overlap region, such that, in the curing process, the upper shell (7) and the lower shell (8) connect to form a monolithic base body (1) of an aerial vehicle.