An aircraft with a fuselage, wings, tail, and surface structure including lightning protection devices.

Abstract

An aircraft (2) is provided, comprising an aircraft fuselage (4), wing groups (6), and tail (8), and a surface structure (10) including a lightning protection device (12), the surface structure being arranged on the aircraft fuselage (4), the wing groups (6), and the tail (8). The lightning protection device (12) has a plurality of conductive elements (14), the conductive elements being arranged in the surface structure (10) in at least a group (16, 20, 21) of elements (14), wherein the conductive elements (14) belonging to the group (16, 20, 21) are arranged at least in a segmental parallel manner and have different spacings (d1, d2, d3, e1, e2, e3) between each other in at least two regions.

Description

Technical Field

[0001] The present invention relates to an aircraft having an aircraft fuselage, wings and tail, and a surface structure including a lightning protection device. Background Technology

[0002] The aircraft is protected from lightning strikes by a lightning protection system. The aircraft is designed with conductive surfaces, allowing current to conduct near the surface and significantly reducing the risk of current penetration through the aircraft structure. This system typically utilizes foils made of highly conductive materials integrated into or within the aircraft's structure. This prevents damage to the fuselage structure.

[0003] Lightning strikes on aircraft typically manifest as lightning hitting one end. For example, the lightning strike may enter the nose radar or the tip of the wing, and the resulting current is conducted along the aircraft and typically discharges into the atmosphere or ground through other ends (such as rudder caps or APU exhaust pipes). Given that such lightning strikes primarily occur in similar forms, specific lightning protection zones are usually defined, and these zones are particularly susceptible to lightning strikes and therefore have lightning protection devices.

[0004] DE 10 2016 121 923A1 illustrates, for example, a material combination that can also be used in the production of lightning arresters in aircraft.

[0005] DE 10 2007 057 491A1 discloses a component for an aircraft having a resin matrix embedded in carbon nanotubes to achieve high electrical conductivity. Summary of the Invention

[0006] Known devices can be used to provide different areas of locally adapted lightning protection on the surface of an aircraft. Therefore, the object of the present invention is to provide an aircraft equipped with alternative lightning protection devices that can be locally adapted, particularly advantageously and flexibly, to different lightning risks.

[0007] This objective is achieved by an aircraft according to the invention. Advantageous improvements are derived from the following description.

[0008] An aircraft is provided, comprising an aircraft fuselage, wing groups, and a tail, and a surface structure including a lightning protection device. The surface structure is arranged on the aircraft fuselage, the wing groups, and the tail. The lightning protection device has a plurality of conductive elements, which are arranged in the surface structure in at least a group of elements. The conductive elements belonging to the group are arranged at least in sections parallel to each other and have different spacings from each other in at least two regions.

[0009] The aircraft can have any structural form and consists of basic main components (fuselage, wing groups, and tail). This does not mean excluding other elements or components. The wing groups and tail may also be combined with each other and are not necessarily implemented in a separate and spaced-out manner. The aircraft fuselage, wing groups, and tail may also have an integrated form, with the aircraft fuselage transitioning into the wing groups, or vice versa.

[0010] In the context of this invention, a surface structure can be understood as the surface configuration of an aircraft's near-surface. This surface structure may include, for example, a fuselage skin, wing skin, or tail skin, with a lightning protection device disposed thereon and one or more protective layers disposed thereon. Therefore, the concept of a surface structure can also vary depending on the type of aircraft and the materials of the fuselage, wing groups, and tail. However, for the core of this invention, the exact composition of the surface structure is not important. It should be noted that arranging a lightning protection device does not aerodynamically affect the outer surface of the aircraft. Of course, an aerodynamically advantageous surface should be maintained without sacrificing the advantageous arrangement of the lightning protection device. The thickness of the conductive elements, their embedding in the surface structure, and the cover plates with one or more protective layers can be adapted to each other in a way that allows the outer surface to be designed in a desired manner and, in particular, to be flat.

[0011] A key aspect of lightning protection devices lies in the use of multiple conductive elements located within a surface structure and capable of conducting current. To prevent damage to the aircraft structure, these conductive elements can conduct the current generated by a lightning strike at the surface structure in a near-surface manner. Here, the conductive elements of the lightning protection device together form at least one group, and these conductive elements can extend parallel to each other, at least in sections. Different spacing between the individual conductive elements can be used to locally adapt to the lightning protection effect.

[0012] Of course, multiple sets of conductive elements can also be arranged in the surface structure. These conductive elements may be located side by side, sequentially, or overlappingly in the surface structure (i.e., in an overlapping arrangement).

[0013] In areas where lightning protection requirements are significantly higher, the spacing between the conductive elements can, for example, be smaller than in other areas. If the spacing between the individual conductive elements is set to zero, this may correspond to a conventional solution with foil or metal mesh. These areas may be located particularly on the front or top of the aircraft.

[0014] In areas where the need for lightning protection is significantly lower, the spacing between the conductive elements may be chosen to be significantly greater than in other areas. This could involve the sides of the aircraft or the front half of the lower fuselage.

[0015] Therefore, the entire surface structure of an aircraft may be equipped with lightning arresters, which can be locally adapted to different lightning protection requirements. Thus, even if the main part of the aircraft is covered, material and weight can be saved in general, and lightning protection can be ideally adapted to the requirements (i.e., without changing the thickness of the metal foil, etc.).

[0016] In an advantageous embodiment, the conductive element is implemented in a strip-like manner. In this respect, the conductive element is elongated and flat, having a main extending direction and being constrained by two opposing edge regions. The width of the conductive element, i.e., the spacing between the opposing edge regions, is significantly smaller than its length. Therefore, the conductive element can extend in strip form within the surface structure of an aircraft, wherein multiple strips extend at least segmentally parallel to each other. More complex surface structure covering shapes can also be achieved by using strip-like conductive elements. It is not necessary to prepare and implement predetermined geometries; rather, the strips can be arranged in a zigzag shape or with specific arcuate shapes during the fabrication of the surface structure.

[0017] Preferably, the conductive element extends continuously within the surface structure. Alternatively, individual elements may be present, either interrupted in the direction or spaced apart from other elements along the direction.

[0018] The conductive element can be made of a metallic material. This metallic material is particularly likely to be copper, copper-based alloys (such as bronze), aluminum, or other metallic materials. Sufficiently high specific conductivity and sufficient achievable current density should be considered in the selection process.

[0019] The conductive element may also have a plastic with a conductive coating. The plastic may be in the form of a coated strip or tape. The strip or tape can typically be composed of a single type of plastic or a layered structure containing multiple plastics. Here, the surface of the conductive element may have interruptions, openings, notches, recesses, etc. The type of plastic is not important here, as long as the coating provides sufficient current strength or conductivity. It may be proposed to use strips formed of thermoplastic or thermosetting plastics, which are flexible and possess bending elasticity, thus allowing them to follow the deformation of the aircraft during flight. Of course, polyamide, Kevlar, or other materials can also be used. The coating can be achieved, for example, by metal vapor deposition.

[0020] Furthermore, it is conceivable to use carbon allotropes that can be incorporated into the surface structure. These carbon allotropes could be implemented, for example, in the form of carbon nanotubes or graphite.

[0021] In one advantageous embodiment, the conductive element has various fibers that are formed into nonwoven fabrics, textiles, woven fabrics, knitted fabrics, braided fabrics, or crocheted fabrics. This type of structure allows for the creation of surface textures that can be very flexibly adapted to desired shapes and orientations in surface structures. This surface structure has fibers that exist regularly or irregularly in the form of weaving, spinning, or stitching together. These structural types can particularly involve plastic fibers with conductive coatings, or fibers with metallic properties.

[0022] However, in an advantageous embodiment, the conductive element can also be solid. Such variations particularly involve strip-shaped segments that are not composed of individual fibers but are made of a solid material. To reduce a certain weight, this solid material may be processed by mechanical methods. It may be proposed to provide a plate or foil with openings and stretch it. This forms an extended metal with a grid-like structure. Copper foil processed in this way is also known under the term "expanded copper foil" (ECF).

[0023] In an advantageous embodiment, a first set of conductive elements is designed, extending parallel to the longitudinal axis of the aircraft fuselage and distributed circumferentially on the fuselage. Therefore, each conductive element in the first set can extend substantially longitudinally along the fuselage. These conductive elements do not necessarily have to have a strictly straight orientation completely parallel to the longitudinal axis. However, the overall extension direction of the conductive elements can preferably extend significantly along the longitudinal axis. Here, for example, one can envision two straight and parallel envelopes arranged opposite each other, surrounding the conductive elements along their main extension direction, and extending parallel to or forming an angle of up to 25° with the longitudinal direction. Local angular deviations from the longitudinal axis may exist. For example, the conductive elements can extend along the longitudinal axis and have one or more arcuate portions surrounding one or more windows in the aircraft fuselage. Generally, the conductive elements can also have a zigzag structure or bend in arrangement. However, it is proposed that all conductive elements in an associated set are arranged such that they have substantially equal spacing between adjacent conductive elements.

[0024] The circumferential distribution of conductive elements can be implemented such that conductive elements extending substantially along the longitudinal axis are arranged at positions distributed throughout the entire circumference of the aircraft fuselage.

[0025] A second set of conductive elements can be designed, which surround the aircraft fuselage circumferentially and are distributed along the longitudinal axis of the aircraft fuselage. Advantageously, the second set is arranged on a fuselage section that also includes the wing root. Similar to the first set shown above, the second set of conductive elements can be arranged such that two adjacent conductive elements are spaced equally apart. Therefore, the conductive elements can be arranged in a ring or spiral pattern, and these conductive elements are not arranged in a single location, but rather in multiple locations along the longitudinal axis.

[0026] A third set of conductive elements can be designed, extending from the aircraft fuselage toward the wingtips. Depending on the wingtips' sweep angle, this third set of conductive elements can be arranged substantially transversely to the longitudinal axis. This allows current to be conducted between the wingtips. The individual conductive elements in this third set can be parallel to each other. Alternatively, this set of elements can also extend parallel to the chords along the wingspan, which belong to their respective, relative wing depths. Zigzag or sawtooth structures can also be present, and straight, parallel envelopes can be parallel to each other or extend along the chords. The conductive elements can also partially overlap with the conductive elements in the second set, for example, on the underside of the wingtips.

[0027] It can be proposed that at least two sets of conductive elements overlap or cross in the lightning protection device. In an advantageous embodiment, the elements of the overlapping sets can be interconnected. In particular, this can be done in the area of ​​the surface structure including the transition from the wing root to the fuselage. For example, current conducted along the wing chord direction along the wing group can be conducted to elements extending longitudinally along the aircraft fuselage. The connection between the elements should have the lowest possible resistance. In this scenario, the current can be spread over a larger surface area, where the cost of repairs after a lightning strike may be lower.

[0028] In an equally advantageous embodiment, the elements of the overlapping groups can be mutually insulated. Here, the current during a lightning strike is concentrated on a smaller surface. This, in particular, reduces manufacturing and maintenance costs.

[0029] The spacing between the conductive elements can be adapted to different requirements. For example, it may be proposed to equip specific areas with surge protectors that are superior to those in other areas of the surface structure. For instance, the aircraft may have at least one wire located radially inward from the surface structure, wherein the spacing between the conductive elements in the radially adjacent area of ​​the surface structure is smaller than the spacing in the more distantly spaced areas of the surface structure. Therefore, the surge protection immediately adjacent to the radially outer area of ​​the wire is locally enhanced relative to the adjacent area.

[0030] The at least one wire may be, for example, a conductive bus.

[0031] The aircraft fuselage may also have an outer skin whose thickness is not constant in the circumferential direction, wherein the spacing between the conductive elements is greater in areas of greater thickness than in areas of less thickness. The likelihood of damage from a lightning strike is lower in areas of greater material thickness than in areas of less thickness. Therefore, it may be proposed that the coverage of the areas in question be adapted to the material thickness in the aforementioned manner.

[0032] Finally, at least one of the aircraft fuselage, wing group, and tail can be at least partially made of plastic. The plastic can be thermoplastic or thermosetting, and optionally fiber-reinforced. The surge arrester is particularly proposed for structures made of non-conductive materials or containing conductive materials, but which are not suitable for absorbing and conducting stronger currents. Deeper, and if necessary, conductive structural layers can be protected by, for example, an external surface structure made of carbon fiber composite material. Attached Figure Description

[0033] Other features, advantages, and application possibilities of the invention will become apparent from the following description of the embodiments and accompanying drawings. Hereinafter, all described and / or illustrated features, in themselves and in any combination, constitute the subject matter of the invention, regardless of their relationship to individual embodiments or embodiments cited herein. Furthermore, the same reference numerals in the drawings represent the same or similar objects.

[0034] Figure 1 A side view shows an aircraft with conductive elements arranged schematically.

[0035] Figure 2a and 2b The detailed design of the conductive components is shown.

[0036] Figure 3 The aircraft is shown in a split top view, which includes conductive elements arranged schematically.

[0037] Figure 4 The aircraft fuselage is shown in a cross-sectional view, which includes conductive elements arranged schematically. Detailed Implementation

[0038] Figure 1 An aircraft 2 with a fuselage 4, wing group 6, and tail 8 is shown. Exemplarily, the aircraft 2 is implemented as a transportation aircraft that may be subject to lightning strikes under corresponding weather conditions.

[0039] A lightning protection device 12 is arranged schematically on the surface structure 10, extending exemplarily along the main part of the aircraft 2. The lightning protection device 12 has a plurality of conductive elements 14 implemented in a strip shape. In the detailed view and partial cross-sectional view, the flat, strip-shaped structure can be seen.

[0040] For example, there is a first group of 16 conductive elements 14 extending along the longitudinal axis 18 of the aircraft 2. Here, the conductive elements 14 may extend parallel to the longitudinal axis 18, or at least substantially along the longitudinal axis 18. This means that the general direction of extension of the conductive elements 14 is along the longitudinal direction 18. Overall, it may form an angle with the longitudinal axis, for example, up to 25 degrees. However, if necessary, this angle may be larger locally.

[0041] There are spacings d1, d2, d3, etc., between the various conductive elements 14. Depending on the lightning protection requirements, the spacings d1 to d3 can be different from each other. In areas of the surface structure 10 that require stronger lightning protection, the corresponding spacings d1, d2, or d3 can be reduced, while in other areas the spacing can be increased.

[0042] Figure 2a Two conductive elements 14, spaced apart and extending parallel to each other, are shown as an example, having a zigzag orientation. Each element 14 may be surrounded by a straight envelope 15 that contacts the edge of the element 14. The envelope extends parallel to each other, and may extend parallel to the longitudinal axis 18. As shown above, the envelope 15 may also form an angle of up to 25° with the longitudinal axis 18.

[0043] Figure 2b Another example of a conductive element 14 arranged near window 17 is shown. The conductive element 14 may have, for example, an arcuate portion 19 surrounding window 17. But in general, the conductive element may extend along longitudinal axis 18.

[0044] exist Figure 3 The upper half of the drawing plane is shown exemplarily in the upper part, and the lower half is shown exemplarily in the lower part. Here, in addition to the first group of 16 conductive elements 14, a second group of 20 conductive elements 14 is also provided, extending circumferentially along the fuselage 4 of the aircraft. Therefore, the elements 14 surround the fuselage 4 and also partially surround the area of ​​the wing group 6 or wing root 25. These elements of the second group 20 are spaced apart by distances e1, e2, and e3. The distances e1, e2, or e3 between the individual elements 14 can also be adjusted to adapt lightning protection to local requirements. The second group is mainly located in the area of ​​the surface structure 10 of the fuselage 4, which also includes the wing root 25.

[0045] As from Figure 3 As can be seen, the conductive elements 14 of the second group 20 can overlap with the conductive elements of the first group 16, thereby forming multiple intersection points. These elements of the overlapping groups 16 and 20 can achieve mutual conductive connections at these intersection points to generate current over a larger area. This may reduce maintenance costs following a lightning strike.

[0046] Alternatively, the crossover point can be made insulated to concentrate the current. This can reduce manufacturing and maintenance costs.

[0047] Two third groups 21 extending on the wing group 6 are also shown. Each conductive element 14 extends, exemplarily, within the entire span of the respective half of the wing group 6 and contacts the wing tip 23. As shown here, the conductive elements 14 may extend parallel to the respective wing chords and, here, follow the relative wing depths. In the region of the wing root 25, the conductive elements 14 of the third group 21 may coincide with or be supplemented by the conductive elements of the second group 20. Thus, intersections may also be formed between the elements 14 of the first group 16 or the second group 20, which, according to the aforementioned criteria, may be implemented as either insulated or conductive.

[0048] Figure 4 A simplified schematic diagram shows the cross-section of the aircraft fuselage 4. It should be reiterated that the outer surface of the aircraft fuselage 4 is not stepped or corrugated, but is aerodynamically advantageous, harmonious, and especially smooth. Figure 4 The illustration should only illustrate that the material thickness of the aircraft fuselage 4 can be changed, and that conductive elements 14 can be installed at different locations on the aircraft fuselage.

[0049] The aircraft fuselage 4 has an outer skin 22 with varying material thicknesses. In the lower section 24, the material thickness of the fuselage outer skin 22 is greater than, for example, in the upper section 26. To accommodate the variable material thickness, the spacing d1 to d12 of the individual conductive elements 14 can be selected to be smaller than that at the lower side 24. Here, d1 to d12 represent the spacing between elements 14 for each side of the fuselage 4, where d1 represents the spacing between the uppermost conductive element 14 and the element 14 following it in the circumferential direction, and d12 represents the spacing between the two lowermost elements 14.

[0050] Exemplarily shown, spacings d8, d9, d10, d11, and d12 belong to the lower half of the fuselage 24 and are significantly larger than spacings d1 to d7 in the upper half of the fuselage 26. Additionally, exemplarily, multiple conductive busbars 28 are arranged radially inward on both sides of the aircraft fuselage 4, with spacings d3, d4, and d5 significantly smaller in the adjacent radially outer region than in all other regions. This minimizes the impact of lightning strikes on the busbars 28.

[0051] Additionally, it should be noted that "having" does not exclude other elements or steps, and "an" or "a" does not exclude multiple. Furthermore, it should be noted that combinations of features already described with reference to one of the above embodiments, as well as other features of the other embodiments described above, may be used. Reference numerals in the embodiments should not be considered limiting.

Claims

1. An aircraft (2) having an aircraft fuselage (4), wing groups (6) and a tail (8) and a surface structure (10) including a lightning protection device (12), the surface structure being disposed on the outer skin of the aircraft fuselage (4), the outer skin of the wing groups (6) and the outer skin of the tail (8), the lightning protection device (12) having a plurality of conductive elements (14), the conductive elements being disposed in the surface structure (10) in at least a group (16, 20, 21) of elements (14), wherein the conductive elements (14) belonging to a group (16, 20, 21) are arranged at least in a segmental parallel manner and have different spacings (d1, d2, d3, e1, e2, e3) between each other in at least two regions. It also has at least one wire (28) located radially inward from the surface structure (10), wherein the spacing (d1, d2, d3, e1, e2, e3) between the conductive elements (14) in the region of the surface structure (10) radially adjacent to the at least one wire (28) is smaller than the spacing in the region of the surface structure (10) further apart from the at least one wire (28).

2. The aircraft (2) according to claim 1, wherein the conductive element (14) is implemented in a strip-like manner.

3. The aircraft (2) according to claim 1 or 2, wherein the conductive element (14) is made of a metallic material.

4. The aircraft (2) according to claim 1 or 2, wherein the conductive element (14) has a plastic with a conductive coating.

5. The aircraft (2) according to claim 1 or 2, wherein the conductive element (14) has a variety of fibers, the fibers forming a nonwoven fabric or textile.

6. The aircraft (2) according to claim 1 or 2, wherein the conductive element (14) has a variety of fibers, the fibers forming woven fabric, knitted fabric, braided fabric or crocheted fabric.

7. The aircraft (2) according to claim 1 or 2, wherein the conductive element (14) is solid.

8. The aircraft (2) according to claim 1 or 2, wherein a first group (16) of conductive elements (14) are provided, the conductive elements extending parallel to the longitudinal axis (18) of the aircraft fuselage (4) and distributed in a circumferential direction on the aircraft fuselage (4).

9. The aircraft (2) according to claim 1 or 2, wherein a second set (20) of conductive elements (14) is provided, the conductive elements being arranged around the fuselage (4) in a circumferential direction and distributed on the fuselage along a longitudinal axis (18).

10. The aircraft (2) according to claim 1 or 2, wherein a third set (21) of conductive elements is provided, the conductive elements extending from the fuselage (4) toward the wing tip (23).

11. The aircraft (2) according to claim 1 or 2, wherein at least two sets (16, 20, 21) of conductive elements (14) are overlapping, wherein the elements (14) of the overlapping sets (16, 20, 21) are interconnected.

12. The aircraft (2) according to claim 1 or 2, wherein at least two sets (16, 20, 21) of conductive elements (14) are overlapping, wherein the elements (14) of the overlapping sets (16, 20, 21) are insulated from each other.

13. The aircraft (2) according to claim 1 or 2, wherein the at least one wire (28) is a conductive bus.

14. The aircraft (2) according to claim 1 or 2, wherein the thickness of the outer skin (22) of the aircraft fuselage (4) is not constant in the circumferential direction, and wherein the spacing between the conductive elements (14) is greater in the region of greater thickness than in the region of less thickness.

15. The aircraft (2) according to claim 1 or 2, wherein at least one of the aircraft fuselage (4), the wing group (6) and the tail fin (8) is at least partially made of plastic.

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