Protective device for an aircraft fuselage

Abstract

This invention relates to a protective device for an aircraft fuselage. To provide protection with the lowest possible weight and good integration into the fuselage, a protective insert (10) is provided for the tail region of the aircraft. The protective insert has a protective panel (12), an absorber (14) supporting the protective panel, and a force transmission device (16) for holding the absorber. The protective panel is configured to slide into contact with the landing / takeoff runway under applied pressure during a tail impact. The protective panel transmits the pressure acting during a tail impact to the absorber. The absorber is implemented in a force-buffering manner to absorb the pressure, wherein a portion of the energy generated by the acting pressure can be absorbed and converted into elastic and / or plastic deformation of at least a portion of the absorber. The force transmission device is configured to hold the protective insert under the tail region of the aircraft and has multiple fastening areas (18).

Description

Technical Field

[0001] This invention relates to a protective device for the fuselage of an aircraft, for example, in the event of a tailstrike. The invention particularly relates to a protective insert for the tail region of an aircraft, a protective system for the tail region of an aircraft, and an aircraft. Background Technology

[0002] During takeoff or landing, unintentional contact / collision between the tail and the runway may occur, for example, when the angle between the aircraft and the runway is too large. Contact with the runway surface can occur by applying different forces to the tail region of the aircraft fuselage. This contact is also referred to as a tail impact or tail strike. Protective measures can be implemented to protect the fuselage. For example, a tail skid can be provided on the underside of the fuselage. The tail skid can be configured as a friction skid or a small tail wheel, for example. Structural reinforcement devices can also be provided for protection. For example, DE 19848122 A1 describes a protective device for the tail of an aircraft fuselage, in which a reinforcement bracket transfers the load to the fuselage load-bearing structure. However, protective measures, especially in commercial passenger aircraft, are often accompanied by additional weight and / or considerably high structural costs. Summary of the Invention

[0003] Therefore, the object of the present invention is to provide a protective measure that has the smallest possible weight and can be well integrated into the fuselage.

[0004] The stated objective is achieved through the subject matter of this invention. Other examples are given herein. The aspects described below are also applicable to protective inserts for the tail region of an aircraft, protective systems for the tail region of an aircraft, aircraft and methods for protecting the fuselage of an aircraft, and the use of protective inserts for tail collisions of aircraft.

[0005] According to the present invention, a protective insert for the tail region of an aircraft is provided. The protective insert has a protective panel, an absorber supporting the protective panel, and a force transmission device for retaining the absorber. The protective panel is configured to slide into contact with the landing runway under applied pressure during a tail impact. The protective panel transmits the pressure acting during the tail impact to the absorber. The absorber is implemented in a force-buffering manner to absorb the pressure, wherein a portion of the energy generated by the acting pressure can be absorbed and converted into elastic and / or plastic deformation of at least a portion of the absorber. The force transmission device is configured to hold the protective insert underside of the tail region of the aircraft and has multiple fastening areas.

[0006] Replaceable tail impact regions enable rapid and simple replacement of structures affected by tail impacts. These regions allow for the integration of tail impact areas, enabling replacement without aircraft-specific tolerances.

[0007] According to one aspect, a new design principle for shock absorption in standard fuselages is provided.

[0008] The fuselage panel can be used in a shape-fitting manner for reinforcement.

[0009] According to one aspect, the force is introduced into the insert and there is partially absorbed by the deformation of the insert or its material structure, so that it is then buffered and further transmitted evenly. Thus, the insert serves both as a means of force introduction and uniform transmission, and as a means of vibration damping.

[0010] The insert is designed to ensure a form-fit connection even when the tail touches the ground and during deformation. The integrity of force transmission during the form fit is always maintained.

[0011] In one example, the plug-in shape fits snugly within the frame or housing.

[0012] In another example, the housing is shaped to fit within the frame of the load-bearing structure, for example, between the partition and the stringers.

[0013] In yet another embodiment, not only the insert but also the receiving portion is shaped to fit together.

[0014] According to one approach, forces undesirably acting on the tail region, such as those occurring upon tail contact during landing, are not directly transmitted to the fuselage structure but are instead absorbed, i.e., buffered, by damping elements. These damping elements are, for example, configured as replaceable protective inserts and are used to absorb forces that occur rather pointwise and transmit them, for example, to a surface, so that the forces can then be directed to the fuselage structure via the frame.

[0015] Protective plug-ins can have shapes such as circles, ellipses, or rectangles.

[0016] According to one example, the absorber includes an absorbent insert having a material structure with multiple cavities. At least a portion of the energy generated by the applied pressure can be absorbed through the elastic and / or plastic deformation of the material structure. The material structure is configured as at least one of the following: a foam structure; a mesh structure; and a foam-like organization.

[0017] According to one example, the absorbent is constructed in a pad-like shape and has a sheath containing a filling portion. The sheath is held at the force transmission device and forms a first side and a second side opposite to the first side, with a protective panel abutting the first side. The filling portion is designed to transmit the pressure transmitted through the protective panel on the first side to the second side of the sheath, such that the force can be transmitted as a tensile force to the force transmission device via the second side of the sheath.

[0018] According to one example, the filling portion is configured as an absorbing filling portion, and at least a portion of the energy generated by the applied pressure can be absorbed by the elastic and / or plastic deformation of the absorbing filling portion.

[0019] According to one example, the absorbent filling is configured as an absorbent insert having a material structure with multiple cavities. At least a portion of the energy generated by the applied pressure can be absorbed through the elastic and / or plastic deformation of the material structure. The material structure is configured as a foam structure, a mesh structure, or a foam-like organization, or a combination thereof, for example, consisting of a foam structure / mesh structure, a foam structure / foam-like organization, a mesh structure / foam-like organization, or a foam structure / mesh structure / foam-like organization.

[0020] According to one example, the protective panel is made of a composite material having a matrix and reinforcing fibers embedded in the matrix, wherein at least a portion of the reinforcing fibers is made of S-glass.

[0021] According to one example, the protective plug has a thermal insulation portion, which reduces the heat input from the external protective panel toward the internal area of ​​the housing.

[0022] According to the present invention, a protection system for the tail region of an aircraft is also proposed. The protection system has a protective insert and a receiving frame according to any of the examples described above. The receiving frame is configured to receive the protective insert and to transfer the force acting on the receiving frame via the protective insert into the fuselage structure of the aircraft. The receiving frame has a receiving portion for the protective insert and multiple connection points for fastening to a load-bearing element on the fuselage structure.

[0023] According to one example, the protective insert remains openable with the housing frame installed. The housing frame is configured to form an access opening to the interior of the fuselage for inspection, maintenance, and / or repair purposes when the protective insert is open or removed.

[0024] According to one aspect, the so-called manhole cover has a dual function. In its first function, the cover is used to close the opening, allowing access to the interior of the fuselage by personnel passing through it. In its second function, the cover is used to prevent the tail from hitting the ground, i.e., a so-called tail-ramming.

[0025] The plate, also known as a plug, can be load-bearing under normal operating conditions, i.e., under flight and ground load conditions, and can be designed to allow for favorable load transfer in the event of a tail impact. For example, the load can be transferred from the impact area of ​​the tail to the surrounding fuselage structure, potentially causing damage to the impact area of ​​the tail impact, which may be replaceable.

[0026] The defined area for tail impact protection is incorporated into the perforated plate. Therefore, tail impact protection is provided within this designated area of ​​the fuselage. This enables the implementation of aircraft-specific repair procedures following a tail impact.

[0027] For example, the fastening device of the protective plug, i.e. the manhole cover, can still function normally after (limited) plastic deformation, such as plastic deformation caused by tail impact.

[0028] For example, the fastening device of the manhole cover fulfills the sealing function. The manhole cover may optionally include a thermal insulation function to protect the hydrogen tank from thermal effects, such as thermal effects caused by tail impact.

[0029] According to one example, the housing frame is disposed in the fuselage panel, which is configured as a removable structural panel to allow for the insertion and removal of larger components, including hydrogen tanks, sections of hydrogen tanks, systems and components of the systems for hydrogen tanks, and hydrogen-driven devices within the fuselage.

[0030] According to the present invention, an aircraft is also proposed. The aircraft has an aircraft fuselage, wings fastened to the aircraft fuselage, and a tail fin fastened to the aircraft fuselage. The aircraft fuselage has a tail region. A protection system according to any of the examples described above is provided on the underside of the tail region.

[0031] In addition, a method for protecting the fuselage of an aircraft and the use of a protective plug for tail collisions of an aircraft are also proposed.

[0032] According to one aspect, the force is introduced into the insert and there is partially absorbed by the deformation of the insert or its material structure, so that it is then buffered and further transmitted evenly. Thus, the insert serves both as a means of force introduction and uniform transmission, and as a means of vibration damping.

[0033] According to one aspect, the protective insert is configured as an absorbent pad formed by two outer sheathing surfaces and a filling portion, so as to transmit the impact force from one sheathing surface to the other sheathing surface via the filling portion. The impact force acting as pressure on one sheathing surface is converted into a tensile force acting in the other sheathing surface via the filling portion. The tensile force can be evenly distributed and transmitted to the frame via the other sheathing surface.

[0034] In the event of a collision, the second side of the sheath is a stretched membrane. The resulting membrane stress is transferred to the frame.

[0035] The protective insert is formed by a flexible core in the sleeve and a cover on the outside.

[0036] It should be noted that the features of the embodiment of the protective plug for the tail region of an aircraft are also applicable to the implementation of the protection system for the tail region of an aircraft, the aircraft, and the method for protecting the aircraft fuselage, and vice versa. Furthermore, features not explicitly mentioned herein can be freely combined with each other. Attached Figure Description

[0037] Embodiments of the invention are discussed in detail below with reference to the accompanying drawings.

[0038] Figure 1 An example of a protective plug-in for the tail area of ​​an aircraft is shown schematically.

[0039] Figure 2 Another example of a protection plugin is shown schematically.

[0040] Figure 3 An example of a protection system for the tail area of ​​an aircraft is shown schematically.

[0041] Figure 4 An example of a protection system at the tail of an aircraft is shown in a side view.

[0042] Figure 5 Shown in vertical cross-section of the aircraft tail Figure 3 An example of a protection system.

[0043] Figure 6 Another example of a protection system at the tail of an aircraft is shown in a side view.

[0044] Figure 7 Shown in vertical cross-section of the aircraft tail Figure 5 An example of a protection system.

[0045] Figure 8 An example of an aircraft is schematically shown in a side view combined with a takeoff / landing runway. Detailed Implementation

[0046] Figure 1An example of a protective insert 10 for the tail region of an aircraft is schematically shown. The protective insert 10 has a protective panel 12, an absorber 14 supporting the protective panel, and a force transmission device 16 holding the absorber. The protective panel 12 is configured to slide into contact with the landing / takeoff runway under applied pressure during a tail impact. The protective panel 12 transmits the pressure acting during a tail impact to the absorber 14. The absorber 14 is implemented in a force-buffering manner to absorb the pressure. A portion of the energy generated by the acting pressure can be absorbed and converted into elastic and / or plastic deformation of at least a portion of the absorber 14. The force transmission device 16 is configured to hold the protective insert 14 underside the tail region of the aircraft and has multiple fastening areas 18.

[0047] exist Figure 1 In the diagram, the protective insert is shown in cross-section, for example, similar to the fuselage cross-section in the case of subsequent installation.

[0048] The term "protective plug-in" refers to a component designed as a protective measure against tail impacts at the tail of an aircraft.

[0049] The term "protective panel" refers to a protective device located at the rear of the fuselage. The protective panel 12 is a plate-like component that may have a curved profile, such as a single or double curve. The protective panel 12 is located externally relative to the fuselage to be protected.

[0050] The protection plug-in 10 can also be called a protection panel. Then, the aforementioned protection panel 12 is a protection device or protection accessory.

[0051] The term "absorbing body" refers to the main component of the protective insert 10 that at least partially absorbs impact forces when, for example, when placed at the tail end on a landing / takeoff runway. The absorbing body 14 may also be referred to as an absorbing core or absorbing structure.

[0052] The term "force transmission device" refers to a holding device also designed to transmit the unabsorbed portion of force.

[0053] Tail-end collision refers to an undesirable impact or collision with the tail of an aircraft. Tail-end collision is also known as a tail ramming.

[0054] The forces acting on the fuselage during a tail impact have a horizontal component arising from the forward motion of the aircraft relative to the landing runway. Friction generated by the contact acts against this forward motion between the protective panel 12 and the surface of the landing runway. The forces acting on the fuselage during a tail impact also have a vertical component arising from the relative downward motion of the tail relative to the takeoff / landing runway. This downward motion of the tail impact can occur, for example, if the angle between the aircraft and the landing runway is too large during landing, or if the angle between the aircraft and the takeoff runway is too large during takeoff.

[0055] The protective panel 12 is designed to slide or rub along the takeoff / landing runway. Therefore, the protective panel 12 is preferably configured with abrasion-resistant surfaces. However, in addition to minimizing material wear, the protective panel 12 is also configured to withstand high temperatures that may arise from intense friction, for example, from considerably high speeds and considerable pressures.

[0056] Absorption means that the vertical deceleration during a tail-end collision is transmitted to the aircraft's structure in a reduced manner. This has a particularly favorable effect when the aircraft carries hydrogen tanks.

[0057] In one example, the protection plug-in 10 is circular. In another example, the protection plug-in 10 is oval or elliptical. In yet another example, the protection plug-in 10 is rectangular or polygonal.

[0058] As an optional solution, Figure 1 As shown, the absorber 14 includes an absorbent insert 20 having a material structure with multiple cavities. At least a portion of the energy generated by the applied pressure can be absorbed through the elastic and / or plastic deformation of the material structure. The material structure is configured as at least one of the group consisting of: foam structures, mesh structures, and foam-like structures.

[0059] The term "absorption plug" refers to the portion of the absorber 14 designed for absorption. The absorption plug 20 can be inserted into the retaining structure or can be configured as a separate body.

[0060] The material structure is characterized by a large number of relatively small connecting regions. These connecting regions can undergo elastic deformation to a certain extent, and also plastic deformation. Through these numerous connecting regions, the relatively large pressure acting on the absorbing plug 20 can be converted into deformation energy and thus absorbed.

[0061] In one example, the material structure can deform elastically and return to its initial state after the force is removed. In another example, the material structure can deform plastically and does not return to its initial state after the force is removed. In yet another example, the material structure can deform both elastically and plastically and does not fully return to its initial state after the force is removed.

[0062] Under conditions of elastic and / or plastic deformation of the material structure, impact energy is converted into deformation energy. This results in a reduction in the transmission of impact impulse to the fuselage structure.

[0063] Figure 2Another example of the protective insert 10 is schematically shown. The absorbent 14 is configured as a pad 22 and has a sleeve 24 in which a filling portion 26 is provided. The sleeve is held at the force transmission device 16 (not shown) and forms a first side 28 and a second side 30 opposite to the first side, with the protective panel abutting against the first side. The filling portion 26 is designed to transmit the pressure transmitted through the protective panel 12 on the first side 28 to the second side 30 of the sleeve 24, so that the force can be transmitted as a tensile force through the second side 30 of the sleeve 24 to the force transmission device 16.

[0064] The term "cushion-like" refers to the form of the absorbent filler 32 within the sheath that holds the filler.

[0065] The term "enclosure" refers to the structure that surrounds the absorbent filler 32. The enclosure can be configured as a membrane or a mesh. The enclosure is used for absorbing and dissipating forces.

[0066] The term "filler" refers to an insert or body section within the enclosure. The filler can be a self-supporting structure or be held in place by the enclosure.

[0067] The pad shape is particularly suitable for the spherical area on the underside of the fuselage at the tail of an aircraft.

[0068] As an optional solution, Figure 2 As shown, the filling portion 26 is configured to absorb the filling portion 32, and at least a portion of the energy based on the applied pressure can be absorbed by the elastic and / or plastic deformation of the absorbing filling portion 32.

[0069] In one alternative embodiment, the absorbent filling portion 32 is configured as an absorbent insert having a material structure with multiple cavities. At least a portion of the energy based on the applied pressure can be absorbed through the elastic and / or plastic deformation of the material structure. The material structure is configured as a foam structure and / or a mesh structure and / or a foam-like organization.

[0070] The term "absorbing filler" refers to a structure that absorbs or cushions at least a portion of the force in the event of a collision, such as the force of a rear-end collision.

[0071] The configuration of the absorbent pad provides a fluid-supported membrane bearing element that buffers and transmits impact forces. For example, impact forces are transmitted to the aircraft's bearing structure, i.e., the fuselage structure, in a buffered or even weakened manner.

[0072] For example, in one alternative, the protective panel 12, in addition to protecting against contact with the landing runway, also at least partially undertakes the function of distributing forces to the absorbent pad. The absorbent pad absorbs the force and further transmits it along the surface through the back of the membrane. Only tensile forces can be transmitted here. This transmission occurs along the surface within the frame of the retaining pad. In one example, the force is transmitted uniformly into the frame.

[0073] In one example, the absorbent filling 32 is configured as an absorbent insert having a material structure with multiple cavities. At least a portion of the energy generated by the applied pressure can be absorbed through the elastic and / or plastic deformation of the material structure. The material structure is configured as at least one of the following: foam structure, mesh structure, and foam-like organization.

[0074] In another alternative, the second side of the sheath is additionally or alternatively configured as an absorbent surface to the absorbent filler. At least a portion of the pressure can be absorbed through the elastic and / or plastic deformation of the absorbent surface.

[0075] The material structure is characterized by a large number of relatively small connecting regions. These connecting regions can undergo elastic deformation to a certain extent, and also plastic deformation. Through these numerous connecting regions, the relatively large pressure acting on the absorbing plug can be converted into deformation energy and thus absorbed.

[0076] In one example, the material structure can elastically deform and return to its initial state after the force is removed.

[0077] In another example, the material structure can undergo plastic deformation and does not return to its initial state after the force is removed.

[0078] In yet another example, the material structure can undergo both elastic and plastic deformation and does not fully recover its initial state after the force is removed.

[0079] Under conditions of elastic and / or plastic deformation of the material structure, impact energy is converted into deformation energy. This results in a reduction in the transmission of impact impulse to the fuselage structure.

[0080] In an alternative, the absorber 14 is held by a truss or rib structure. For example, the absorber mass presses against a surface held by the truss, the force is transferred from the surface into the truss, and then the truss distributes the force evenly to the frame.

[0081] In another alternative, the absorber 14 comprises a multi-dimensional rib structure, wherein force is directed from one face to the ribs. The ribs are configured, for example, as a multi-level hierarchical mesh: smaller ribs are held at larger ribs, and the larger ribs are held at even larger ribs. The ribs form a mesh structure. Through deformation, such as elastic and / or plastic deformation, the impact energy can be at least partially converted into deformation energy, i.e., at least partially absorbed. For example, some of the force can be absorbed via the filling portion, and another portion can be absorbed via the mesh.

[0082] The forces generated during a tail impact are distributed to the frame or ring structure so that they can be transferred to the fuselage from there.

[0083] In one alternative, the protective insert and force transmission device are hermetically held within a housing frame, which in turn is hermetically held within the fuselage structure and designed for pressure loading of internal fuselage areas. In one example, the rear region housing the protective system is pressure-loaded. In another example, the rear region housing the protective system is not pressure-loaded, but is located behind a pressure baffle in the direction of travel, separating the pressure-loaded area from the unpressure-loaded area.

[0084] As a further alternative, in Figure 2 (and also) Figure 3 and Figures 4-7 As shown in the figure, the absorber 14 has a raised cross-sectional shape in the vertical direction.

[0085] In one alternative, the absorber 14 is proposed to have a rounded shape in the horizontal direction.

[0086] In one example, the absorber is raised. In the horizontal direction, the absorber has a rounded shape.

[0087] In another example, the absorber is not raised, but protrudes as a truncated pyramid, truncated prismatic pyramid, or truncated cuboid. In the horizontal direction, the absorber has a rounded shape.

[0088] In one example, the absorber is raised. Horizontally, the absorber has a polygonal or rectangular shape.

[0089] In yet another example, the absorber protrudes as a truncated pyramid, truncated prism, or truncated cuboid, and has a polygonal or rectangular shape in the horizontal direction.

[0090] The term "bulge" refers to a convex, outward-curving shape on both sides. Therefore, a slightly protruding area is formed on the outer side, which ensures that force is directed into the protective insert 10 during a tail impact, and that the surrounding fuselage area does not come into contact with the landing / takeoff runway under different flight maneuvers. On the inner side, the shape provides the advantage of converting externally applied pressure into tensile stress, which is then transferred to the frame.

[0091] The term "rounded" refers to a shape that allows for the most uniform force input possible, such as a shape that does not have angled intersecting edges. Rounded shapes can be, for example, circular, oval, elliptical, or egg-shaped, or rounded in a different way.

[0092] The absorber 14 is configured as a spherical pad, for example, having a lenticular cross-section.

[0093] The vertical direction refers to the subsequent installation or the main force of the impact. For example, the vertical direction extends laterally to the protective panel. The horizontal direction refers to the subsequent installation or the main force of the impact. For example, the horizontal direction extends parallel to the protective panel 12.

[0094] As an alternative not shown in detail, the protective panel 12 is proposed to be made of a composite material having a matrix and reinforcing fibers embedded in the matrix, wherein at least a portion of the reinforcing fibers is made of S-glass.

[0095] The term "S-glass" refers to a type of glass fiber characterized by very high strength, very high stiffness, and a very high melting point. Typically, S-glass has the highest strength, stiffness, and melting point values ​​among commercially available glass reinforcing fibers. S-glass fibers are also used, for example, in lightweight ballistic protective structures.

[0096] For example, reinforcing fibers are designed for high mechanical requirements, even at high temperatures.

[0097] For example, the reinforcing fibers are made of aluminosilicate glass with magnesium oxide additives.

[0098] The protective panel 12 is characterized by high abrasion resistance. This abrasion resistance is designed for a wide temperature range, from -30°C to 120°C or higher. Low temperatures are caused, for example, by winter conditions in the landing and takeoff runway areas, but also by the low temperatures that the external protective panel may cool to during flight operations at common cruising altitudes. High temperatures are caused by heat generated during friction, but also to some extent by summer conditions and, particularly, by sunlight exposure and the high surface temperatures present in the landing and takeoff runway areas.

[0099] As another alternative, Figure 2 As shown in dashed lines, the protective plug 10 may have a thermal insulation portion 34, which reduces the heat input of the external protective panel 12 toward the internal area of ​​the housing.

[0100] The term "heat input" here primarily refers to the heat generated by the tail impact at the protective panel.

[0101] The term "thermal insulation" refers to measures that reduce heat loss to the interior of the fuselage, where, for example, hydrogen tanks may be located. In one example, the thermal insulation 34 has a lower thermal conductivity than the absorbing structure. In another example, the thermal insulation 34 has reduced heat radiation. In yet another example, the thermal insulation 34 has targeted heat dissipation laterally into the fuselage structure. In still another example, the thermal insulation has an active cooling section.

[0102] For example, the thermal insulation part 34 is configured as a layer in the protective plug 10.

[0103] In another example, thermal insulation 34 is applied as a layer on the inside of protective plug 10.

[0104] In an alternative embodiment, the thermal insulation part 34 is connected to the frame structure of the retaining protective plug 10. Through, for example, the annular screw portion of the frame structure, heat can be introduced as evenly as possible, in addition to the retaining force.

[0105] In one example, the absorber 14, which is configured as a pad, has a metal wall or metal sheath or metal film on its outer side and a thermally insulating wall or film sheath on its inner side.

[0106] The outer side is the side that points outward, and is covered, for example, by a protective layer. The inner side is the side that points inward when the fuselage is in the installed state, and is covered, for example, by additional thermal insulation.

[0107] In one example, the thermal insulation is formed by the absorber itself.

[0108] In another example, the thermal insulation is integrated with the absorber.

[0109] In yet another example, the thermal insulation portion is configured as a separate component as a supplement to the absorber.

[0110] Figure 3 An example of a protection system 100 for the tail region of an aircraft is schematically shown. The protection system 100 has an example of a protective insert 10 according to any of the examples described above, and a receiving frame 102. The receiving frame 102 is configured to receive the protective insert 10 and to direct the forces acting on the receiving frame 102 via the protective insert 10 into the fuselage structure of the aircraft. The receiving frame 102 has a receiving portion 104 for the protective insert and a plurality of connection points 106 for fastening to a load-bearing element on the fuselage structure.

[0111] The term "protection system" refers to measures used to protect the fuselage in the event of a rear-end collision. Protective measures may be designed, for example, as systems in which components are designed to be replaceable.

[0112] The term "retaining frame" refers to a retaining device used to protect the plug. For example, the retaining device may be configured as a wraparound frame.

[0113] In another example, the device is configured as a partially wraparound frame.

[0114] The housing frame 102, for example, has multiple connecting pieces for fastening to the frame and stringers.

[0115] The housing frame 102 is designed to distribute and uniformly direct forces into the fuselage as much as possible.

[0116] According to one aspect, a defined interface is provided for tail-impact protection measures. The receiving frame 102 forms a predetermined connection between the absorber / protection element and the aircraft fuselage.

[0117] The size of the protective plug is configured to cover potential collision points at the tail.

[0118] In one example, the protective insert can only be inserted into the receiving frame 102 in a predetermined insertion direction designed for the intended action direction of a rear-end collision.

[0119] exist Figure 3 In the diagram, the protection system 100 is shown in conjunction with a schematically illustrated fuselage structure having a fuselage shell 110 and a load-bearing structure 112 located behind the shell. Furthermore, for better understanding, a takeoff / landing runway 114 is schematically shown. Different forces act upon contact with the protection insert 10, for example, during a tail-impact collision. Contact or collision is indicated by broad arrows 116. The first arrow 118 shows the downward force of gravity acting on the aircraft; the second arrow 120 indicates the direction of flight, and the third arrow 122 indicates the frictional force at the contact surface.

[0120] In an alternative embodiment of the protection system 100, not shown in detail, the protection insert 10 remains openable with the housing frame 102 installed. The housing frame 102 is configured to form an access opening toward the interior of the fuselage for inspection, maintenance, and / or repair purposes when the protection insert 10 is open or removed.

[0121] The term "retains openability" refers to the possibility of opening and closing the protection plug 10. One example is a protection plug 10 that is movable and retained. Another example is a protection plug that is detachably retained. Detachability means that the installed protection plug 10 can be removed and subsequently reinstalled.

[0122] The protective insert 10 is, for example, part of a cover or maintenance cover, so that actual disassembly is not required.

[0123] In another example, the protective plug 10 is detachably held for opening, i.e., it is removably held so that temporary disassembly can be performed.

[0124] The protective plug 10 is removable when the housing frame 102 is installed and secured. After being detached, the protective plug 10 can be re-secured. Therefore, the protective plug 10 is reinstallable with the housing frame 102 installed.

[0125] The term "access opening" refers to an opening designed to allow personnel access to areas of the fuselage. For example, access openings are also designed to allow materials and tools to be inserted and removed through the opening.

[0126] The protective insert 10 forms a dual-function component. On one hand, the protective insert serves as a replaceable component, designed for optimal protection and replaceable upon wear. On the other hand, the protective insert serves as an openable closure for inspecting the passageway.

[0127] Therefore, it is proposed to integrate the protective plug 10 into the opening maintenance cover, i.e., to protect the panel function. The opening maintenance cover can also be called a "manhole".

[0128] The opening edge is designed to direct force into the fuselage structure.

[0129] The protection plug-in 10 can integrate i) channel, ii) protection and iii) damping functions.

[0130] The protective plug 10 serves as a load-bearing panel, for example, under normal flight conditions, to withstand basic loads and forces during flight operations. Simultaneously, the panel can receive and partially absorb the load when the tail section touches the ground.

[0131] For example, the housing frame 102 is held in place at the fuselage structure by means of a non-detachable connecting device, such as a rivet. The protective insert 10 is held in place at the housing frame 102 by means of a detachable connecting device.

[0132] The removability enables a second function: by removing the protective plug 10, a temporary access opening to the tail area can be provided, for example, for maintenance and repair purposes.

[0133] Removability provides the protection device with replaceability. For example, the protection plug 10 can be replaced at regular intervals or according to usage frequency or load conditions.

[0134] In one example, it is proposed that the protective plug 10 can also be detached and disassembled in the event of plastic deformation of the absorber 14, so that it can be accessed through the opening, for example, to reach the hydrogen tank for inspection purposes.

[0135] In one example, the protection system 100 is inserted between two partitions. In another example, the length of the protection system 100 in its installed state is greater than the net distance between the two partitions. Therefore, an interruption is inserted into the partition to allow the installation of the protection system 100. The interruption forms a frame for redirecting the circumferential force within the interrupted partition.

[0136] A tail-impact protection measure is proposed that can be easily integrated into the existing fuselage structure and can be implemented with relatively low structural costs. Another advantage is the small added weight. This is particularly important in future propulsion systems, such as fuel cells or other propulsion units with a higher component weight than conventional propulsion systems and common kerosene tanks, as well as onboard hydrogen tanks. The proposed tail-impact protection measure contributes to minimizing the weight of the fuselage structure.

[0137] Figure 4 An example of a protection system 100 located at the tail 150 of an aircraft is shown in a side view. The aircraft is exemplarily shown as having a hydrogen tank 152. The protection system is located in the rear region on the lower side of the tail.

[0138] Figure 5 Shown in vertical cross-section of the tail section 150 of the aircraft Figure 3 An example of the protection system 100 in the aircraft. The aircraft has a fuselage structure 154, schematically shown, which includes, for example, surrounding stringers and bulkheads (not shown in detail) extending transversely to them in the longitudinal direction. The fuselage structure 154 is covered by an outer shell 156.

[0139] Figure 6 Another example of the protection system 100 is shown in a side view at another example of the tail section 150 of the aircraft.

[0140] As an optional solution Figure 6 and Figure 7 As shown, the housing frame 102 of the protection system 100 is disposed in the fuselage panel, which is configured as a removable structural panel 108 to allow for the insertion and removal of larger components, including hydrogen tanks, hydrogen tank sections and systems, and components of the system for the hydrogen tanks and hydrogen drive devices within the fuselage.

[0141] The removable structural panel 108 can be connected to the rest of the fuselage structure, for example, via a defined interface 109.

[0142] Figure 7 Shown in vertical cross-section of the aircraft tail Figure 5 An example of a protection system.

[0143] The term "fuselage panel" refers to a plate-like component inserted into the fuselage. Fuselage panels can have a curved shape. The external shape of the fuselage panel can conform to the orientation of the fuselage's load-bearing structural members, i.e., bulkheads and stringers. The fuselage panel has a load-bearing structure, for example, similar to the adjacent remaining fuselage area or section. The fuselage panel may also have an outer shell.

[0144] The term "structural panel" refers to the load-bearing characteristics of a panel. For example, a fuselage panel is part of the main structure of an aircraft.

[0145] One variant proposes integrating the protective insert into the fuselage housing, for example, in conjunction with the function of a maintenance cover. However, to accommodate and remove larger structures within the fuselage, such as cases, the fuselage does not have large removable panels; instead, it can be opened via a so-called orbital joint. An orbital joint is, for example, a detachable, wraparound connection between two fuselage sections.

[0146] As an alternative, the protection system is configured to allow for the replacement of protective inserts, which can be inserted from one aircraft into another. This requires high precision and small clearances in the fastening interfaces, such as holes. This so-called "interchangeability" offers advantages in maintenance, service, and repair.

[0147] Figure 8 An example of an aircraft 200 is schematically shown in a side view combined with a takeoff / landing runway. The aircraft 200 has an aircraft fuselage 202, wings 204 fixed to the aircraft fuselage, and a tail fin 206 fixed to the aircraft fuselage. The aircraft fuselage has a tail region 208. An example of a protection system 100 according to any of the above examples is provided on the lower side 210 of the tail region 208.

[0148] The aircraft is shown exemplarily with its landing gear 212 lowered.

[0149] The protection system 100 is suitable for aircraft, for example, those with hydrogen tanks located in the tail area. The shock-absorbing effect of the protection module specifically means a reduction in the forces acting on the fuel tank retaining device.

[0150] In one alternative, a fuselage structure for an aircraft is proposed. The fuselage structure has multiple frames and multiple stringers. The frames and stringers are connected to each other and form a retaining shell to enclose the internal fuselage region. The fuselage structure has a tail region. A protection system according to any of the examples described above is provided on the underside of the tail region of the fuselage structure. The protection system directs the impact force during a tail collision into the fuselage structure. The frames may also be referred to as bulkheads.

[0151] In practical applications, measures are proposed to prevent tail-end collisions, such as through pilot intervention or control measures. For example, control interventions can be implemented to prevent aircraft from taking excessive angles relative to the takeoff / landing runway during takeoff, landing, or go-around maneuvers.

[0152] In one alternative, the protection plug-in or the protection system according to any of the examples above is located on the underside of the aircraft.

[0153] Therefore, if an unintended contact between the tail and the takeoff / landing runway does occur, i.e., a tail strike, and if the tail area of ​​the aircraft still touches the ground during takeoff or landing despite other measures, at least a portion of the absorber's elastic and / or plastic deformation and the transmission of the cushioning pressure to the aircraft fuselage may occur.

[0154] In another alternative, a protective insert for tail impact of an aircraft is proposed. The protective insert has an external protective panel for sliding contact with the landing runway under applied pressure, and an absorber supporting the protective panel. The protective panel transmits the pressure exerted during a tail impact to the absorber. The absorber is implemented in a force-buffering manner to absorb the pressure and includes an absorber insert having a material structure with multiple cavities, wherein at least a portion of the energy generated by the applied pressure can be absorbed through elastic and / or plastic deformation of the material structure. The material structure is configured as at least one of the following: foam structure, mesh structure, and foam-like organization.

[0155] In another alternative, the use of a protective plug-in for tail collisions of an aircraft is proposed, according to any of the examples above.

[0156] The above embodiments can be combined in different ways and methods. In particular, aspects of the device can also be used in the implementation of the method, and vice versa.

[0157] Additionally, it should be noted that "comprising" does not exclude any other elements or steps, and "a" does not exclude multiple. Furthermore, it should be noted that the features or steps described with reference to one of the above embodiments can also be used in combination with other features or steps of the other embodiments described above. Reference numerals in the claims should not be construed as limiting.

Claims

1. A protective plug-in (10) for the tail region of an aircraft, said protective plug-in having: - Protective panel (12); - The absorber (14) supporting the protective panel; and - A force transmission device (16) that maintains the absorber; The protective panel is configured to slide into contact with the landing / takeoff runway under applied pressure during a tail impact; and the protective panel will transfer the pressure exerted during a tail impact to the absorber. The absorber is implemented in a force-buffering manner to absorb the pressure, wherein a portion of the energy generated by the applied pressure can be absorbed and converted into elastic and / or plastic deformation of at least a portion of the absorber; and The force transmission device is configured to hold the protective plug at the underside of the tail region of the aircraft and has multiple fastening areas (18).

2. The protective insert according to claim 1, wherein the absorber comprises an absorbent insert (20) having a material structure with multiple cavities, wherein at least a portion of the energy generated by the applied pressure can be absorbed through the elastic and / or plastic deformation of the material structure, and The material structure is configured to be at least one of the following groups: - Foam structure; - Grid structure; as well as - Foamy tissue.

3. The protective plug-in according to claim 1 or 2, wherein the absorbent is formed in a pad-like shape and has a sleeve (24) in which a filling portion (26) is provided. The sheath is held at the force transmission device and forms a first side (28) and a second side (30) opposite to the first side, with the protective panel abutting against the first side; and The filling portion is designed to transfer the pressure transmitted through the protective panel on the first side to the second side of the sleeve, so that the force can be transmitted as a tensile force to the force transmission device via the second side of the sleeve.

4. The protective plug according to claim 1, 2 or 3, wherein the filling portion is configured as an absorbent filling portion (32), and at least a portion of the energy generated by the applied pressure can be absorbed by the elastic and / or plastic deformation of the absorbent filling portion.

5. The protective insert of claim 4, wherein the absorbent filling portion is configured as an absorbent insert having a material structure with a plurality of cavities, wherein at least a portion of the energy generated by the applied pressure can be absorbed by the elastic and / or plastic deformation of the material structure, and wherein the material structure is configured as at least one of the following groups: Foam structure, mesh structure and foam-like tissue.

6. The protective plug according to any one of the preceding claims, wherein the absorber has a raised cross-sectional shape in the vertical direction; and The absorber has a rounded shape in the horizontal direction.

7. The protective plug-in according to any one of the preceding claims, wherein the protective panel is made of a composite material having a matrix and reinforcing fibers embedded in the matrix, wherein at least a portion of the reinforcing fibers is made of S-glass.

8. The protective plug-in according to any one of the preceding claims, wherein the protective plug-in has a thermal insulation portion (34) by means of which the heat input from the external protective panel toward the interior area of ​​the housing is reduced.

9. A protection system (100) for the tail region of an aircraft, the protection system having: - The protection plug-in (10) according to any one of the preceding claims; and - Retaining frame (102); The receiving frame is configured to receive the protective plug and to transfer the forces acting on the receiving frame via the protective plug into the fuselage structure of the aircraft. and The housing frame has a housing portion (104) for the protective plug and multiple connection points (106) for fastening to the load-bearing elements of the fuselage structure.

10. The protection system of claim 9, wherein the protection plug remains openable with the installed receiving frame in place; and The receiving frame is configured to form an access opening into the interior of the fuselage for inspection, maintenance and / or repair purposes when the protective insert is opened or removed.

11. The protection system according to claim 9 or 10, wherein the housing frame is disposed in the fuselage panel, the fuselage panel being configured as a removable structural panel (108) to enable the insertion and removal of larger components, the larger components including a hydrogen tank, a section of the hydrogen tank, a system and components of the system for the hydrogen tank and a hydrogen drive device within the fuselage.

12. An aircraft (200) comprising: - Aircraft fuselage (202); - The wing (204) fastened to the fuselage of the aircraft; and - Tail fin (206) fastened to the fuselage of the aircraft. The aircraft fuselage described therein has a tail region (208); and A protection system (100) according to any one of claims 9 to 11 is provided on the lower side (210) of the tail region.

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