Patent Application
20250002134
This application claims the benefit of French Patent Application Number 2306863 filed on Jun. 29, 2023, the entire disclosure of which is incorporated herein by way of reference.
The present invention relates to an aircraft having an attachment system with a fitting for fastening an element such as a pipe or a skid to a fuselage of the aircraft.
An aircraft conventionally has a fuselage to which two wings are fastened and each wing supports at least one engine, in particular a jet engine. At the central part of the fuselage, the latter is covered with a belly fairing.
Certain elements are fastened to the outside of the fuselage, such as air pipes that run along the fuselage between the fuselage and the belly fairing. It may happen that one of these pipes is partly outside the belly fairing and is then in contact with external elements, such as the engines, and if lightning strikes the engine, an induced electric current can then flow through the pipe.
In order to prevent the current from propagating to the fuselage, or even to the inside of the latter, the fastening of the pipe to the fuselage requires the use of specific materials that may be relatively expensive.
It is therefore necessary to define an arrangement that makes it possible to reduce the cost necessary for fastening a fitting, in particular a metal fitting, to the outside of the fuselage while at the same time ensuring electrical insulation.
In the same way, in order to reduce the damage to the fuselage during a crash landing, for example without landing gear, skids are provided that are fastened to the outside of the fuselage, and these skids then slide on the tarmac. This sliding generates heating of the skid and it is therefore desirable to prevent this heating from being transmitted to the fuselage and to the inside thereof. In order to avoid this heating, specific and expensive materials are used.
It is therefore necessary to define an arrangement that makes it possible to reduce the cost necessary for fastening a fitting, in particular a metal fitting, to the outside of the fuselage while at the same time ensuring thermal insulation.
In general, it is necessary to find an arrangement that makes it possible to limit the passage of disturbances such as an electric current or a heat flow towards the fuselage.
An object of the present invention is to propose an aircraft having an attachment system with a metal fitting for fastening an element to the outside of the fuselage of the aircraft.
To this end, an aircraft having a fuselage, an element and at least one attachment system for fastening the element to the outside of said fuselage is proposed, the attachment system having:
With such an attachment system, this makes it possible to limit the passage of disturbances such as an electric current or a heat flow towards the fuselage by incorporating a buffer plate.
Advantageously, the plate is constituted of an electrically insulating material arranged to prevent the passage of current.
Advantageously, the plate is constituted of a thermally insulating material arranged to limit the passage of heat.
Advantageously, the attachment system has an intermediate plate disposed against the second face of the plate and intended to be disposed against the fuselage.
Advantageously, the intermediate plate is constituted of the same material as the material constituting the plate.
Advantageously, the plate is fastened to the fuselage by bolts, wherein each one has a screw with a head and a nut, for each bolt, the plate has a through-piercing and the fuselage has a through-orifice aligned with the piercing, for each bolt, the screw of said bolt passes through a piercing and the associated orifice so as to sandwich the plate and the fuselage between the head of the screw of said bolt and the nut of said bolt, and the piercings of the plate are arranged such that there is no contact between the shoe and the heads of the screws.
Advantageously, the plate is wider than the shoe and the piercings are on the outside of and at a distance from the shoe.
The above-mentioned features of the invention, along with others, will become more clearly apparent upon reading the following description of one exemplary embodiment, said description being given with reference to the appended drawings, in which:
In the following description, terms relating to a position are considered in relation to an aircraft in a position of forward movement, i.e. as shown in
In the following description, and by convention, the X direction is the longitudinal direction of the engine 102, with positive orientation in the direction of forward movement of the aircraft 100, the Y direction is the transverse direction of the aircraft 100, which is horizontal when the aircraft 100 is on the ground, and the Z direction is the vertical direction or vertical height when the aircraft 100 is on the ground, these three directions X, Y and Z being mutually orthogonal.
In the embodiment of the invention that is presented here, the element 206 is a pipe, such as an air pipe supplying, for example, an engine 102, but it may be another element. For example, the element 206 may be a skid, intended to ensure that the aircraft 100 slides on the tarmac in the event of landing without landing gear, for example.
The element 206 is fastened to the fuselage 101 by at least one fitting 208 as one with the fuselage 101. In the embodiment of the invention that is presented in
The fitting 208 in this case takes the form of a female clevis in which the element 206 is fastened, in this case by way of a bar 210. The fitting 208 in this case has a shoe 209 that is in this case a flat wall that allows the fitting 208 to be fastened to the fuselage 101 using fastening bolts 304 described below.
The attachment system 300 has the fitting 208 and a plate 302.
The plate 302 has a first face 302a and a second face 302b. The second face 302b is oriented towards the fuselage 101 and on the outside of the latter.
The plate 302 is fastened to the fuselage 101 by any suitable fastening means, such as threaded fasteners, rivets, welding spots, etc.
In the embodiment of the invention that is presented here, the plate 302 is fastened to the fuselage 101 by way of a plurality of bolts 306, wherein each one has a screw 306a with a head and a nut 306b. To this end, the plate 302 has through-piercings 303 and the fuselage 101 has orifices 305 that are likewise through-orifices positioned in alignment with the piercings 303 when the plate 302 is pressed against the fuselage 101. For each bolt 306, the screw 306a of said bolt 306 passes through a piercing 303 and the associated orifice 305 and the plate 302 and the fuselage 101 are thus sandwiched between the head of the screw 306a of said bolt 306 and the nut 306b of said bolt 306. In the embodiment of the invention that is presented in
In order to prevent the passage of current or heat between the shoe 209 and the bolts 306, the piercings 303 in the plate 302 are arranged so that there is no contact between the shoe 209 and the heads of the screws 306a in the assembled position. In the embodiment of the invention that is presented here, the plate 302 is wider than the shoe 209 and the piercings 303 are on the outside of and at a distance from the shoe 209.
The shoe 209 of the fitting 208 has a contact face 208a that is in contact with the first face 302a of the plate 302. The plate 302 is thus between the fitting 208 and the fuselage 101.
The attachment system 300 also has at least one fastening bolt 304, wherein each one has a screw 304a and a nut 304b.
For each fastening bolt 304, the plate 302 has, on the side of the second face 302b, a hole 308 passing through the plate 302 and which, in the form illustrated, is in this case a countersunk hole, in which the head of the screw 304a is housed so as to be flush with the second face 302b which thus remains flat.
Each nut 304b is screwed to the associated screw 304a, sandwiching the plate 302 and the fitting 208. Each nut 304b is thus against a bearing face 208b that is the face of the shoe 209 opposite the contact face 208a.
With such an assembly, it is possible to protect the fuselage 101 from possible disturbances coming from the element 206 through the fitting 208, such as an electric current or a heat flow. The plate 302 thus constitutes a screen, preventing disturbances (current, heat) from reaching the fuselage 101.
The head of the screw 304a does not pass through the fuselage 101 and it is integrated in the plate 302 such that said head is flush with the second face 302b of the plate 302 and does not extend beyond it.
The screws 304a and the nuts 304b of the fastening bolts 304 make it possible to fasten the plate 302 to the fitting 208 and therefore to the element 206 without passing though the fuselage 101, the plate 302 being fastened to the fuselage 101 by the screws 306a and nuts 306b of the bolts 306.
For example, in the case in which the element 206 is a skid, the plate 302 is advantageously constituted of a material that is arranged to limit the passage of heat and thus heating of the skid will lead to limited heating of the fuselage 101. Such a material thus acts as a thermal insulator, and it can be made of mica, glass fiber reinforced polymers, titanium alloy, carbon fiber reinforced polymers, etc.
For example, in the case in which the element 206 is a pipe liable to receive a lightning strike that could induce a current in the pipe and in the fitting 208, in particular when it is a metal fitting, the plate 302 is advantageously constituted of a material that is arranged to prevent the passage of the current and thus a lightning strike does not reach the fuselage 101. Such a material thus acts as an electrical insulator, and it can be made of ABS, glass fiber reinforced polymers, etc.
As a result of the presence of the belly fairing 202, the bolts 306 cannot be reached directly by a potential lightning strike.
According to one particular embodiment, the plate 302 has a minimum electrical resistance of 1 ohm.
In order to further limit the passage of any electric currents between the fitting 208 and the fuselage 101, the attachment system 400 has an intermediate plate 402 that is disposed between the second face 302b of the plate 302 and the fuselage 101, so as to separate the heads of screw 304a of each fastening bolt 304 from the fuselage 101. The intermediate plate 402 is thus against the second face 302b of the plate 302 on one side and against the fuselage 101 on the other side.
For each bolt 306, the intermediate plate 402 has a through-bore 403 into which the screw 306a of said bolt 306 is introduced.
Although this second embodiment is more particularly suitable in the case of induced currents, it can be implemented for the case relating to heat transfer.
Depending on the circumstances, the intermediate plate 402 is constituted of the same material as the material constituting the plate 302, i.e. a thermally insulating material or an electrically insulating material.
In the embodiments of the invention that are presented in
While at least one exemplary embodiment of the present invention(s) is disclosed herein, it should be understood that modifications, substitutions and alternatives may be apparent to one of ordinary skill in the art and can be made without departing from the scope of this disclosure. This disclosure is intended to cover any adaptations or variations of the exemplary embodiment(s). In addition, in this disclosure, the terms “comprise” or “comprising” do not exclude other elements or steps, the terms “a” or “one” do not exclude a plural number, and the term “or” means either or both. Furthermore, characteristics or steps which have been described may also be used in combination with other characteristics or steps and in any order unless the disclosure or context suggests otherwise. This disclosure hereby incorporates by reference the complete disclosure of any patent or application from which it claims benefit or priority.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2306863 | Jun 2023 | FR | national |
