Patent Application
20120132752
This invention refers to an interface arrangement between two components of an aircraft structure having an aerodynamic contour and, more in particular, to an interface arrangement for maintaining the continuity of the aerodynamic contour in the interface.
As is well known, weight is a fundamental aspect in the aeronautic industry and therefore there is a current trend to use composite materials instead of metallic materials for aircraft structures with an aerodynamic contour such as lifting surfaces and fuselages.
The composite materials that are most used in the aeronautical industry consist of fibers or fiber bundles embedded in a matrix of thermosetting or thermoplastic resin, as a preimpregnated or “prepreg” material. Their main advantages refer to:
Their high specific strength with respect to metallic materials. It is the strength/weight equation.
Their excellent behavior before fatigue loads.
The possibilities of structural optimization due to the anisotropy of the material and the possibility of combining fibers with different orientations, allowing the design of the elements with different mechanical properties to be adjusted to the different needs in terms of applied loads.
The main structure for aircraft lifting surfaces consists of a leading edge, a torsion box, a trailing edge a root joint and a tip. The torsion box consists of several structural elements: upper and lower skins stiffened by stringers on one side; spars and ribs on the other side. Typically, the structural elements forming the torsion box are manufactured separately and are joined with the aid of complicated tooling to achieve the necessary tolerances, which are given by the aerodynamic, assembly and structural requirements.
The interface between those components whose outer surface belongs to the aircraft aerodynamic contour such as a skin an a leading edge panel in the case of a lifting surface shall be arranged to comply with the aerodynamic requirements in terms of continuity, smoothness and drag, in the interface area.
In the prior art is well known the use of aerodynamic smoothing sealants covered by a paint layer to seal the gaps involved in said interfaces. These sealants are typically uncured pastes suitable for application by extrusion gun or spatula. They can cure at low temperatures and have a good adhesion to common aircraft substrates. However, when the gaps have certain dimensions the application and maintenance of said sealants raise several problems such as cracking, loosening or even detachment. These problems arise more often when the components joined are composite parts because their joints usually involve bigger gaps than metallic interfaces.
This invention is focused on the solution of this problem.
One objective of the present invention is to provide a smoother interface arrangement between components of an aircraft structure with an aerodynamic contour that assures the continuity of the aerodynamic contour in that interface area, as well as an easy maintenance, filling the gap associated to the interface.
Another objective of the present invention is to provide an interface arrangement between components of an aircraft structure with an aerodynamic contour that assures the continuity of the aerodynamic contour in the interface area reducing significantly the amount of aerodynamic smoothing sealant applied to seal the gap associated to the interface.
In one aspect these and other objectives are met by an interface arrangement between a first component and a second component of an aircraft structure having an aerodynamic contour, the first component having a joggle so that it includes a first area which surface belongs to the aircraft aerodynamic contour and a second area where the joint with the second component takes place, the second component having a surface belonging to the aircraft aerodynamic contour, in which a sealing part, suitable shaped to maintain the continuity of the aircraft aerodynamic contour in the interface area between said components as well as to fill the expected gap between said components, is joined to the second component.
In a preferred embodiment, said sealing part is made of an elastomeric material. Hereby it is achieved a sealing part able to be prefabricated and easy to install over said second component.
In another preferred embodiment the gap filled with said sealing part has a width W comprised between 10-15 mm and a height H greater than 3 mm. Hereby it is achieved an interface arrangement applicable to many aircraft structures.
In another preferred embodiment said first and second components are composite parts. Hereby it is achieved a suitable smooth aerodynamic interface arrangement of components involving gaps of certain dimensions.
In another preferred embodiment, said sealing part is joined to the second component in a detachable manner so that it can be easily replaced when deteriorated or damaged. Hereby it is achieved a sealing part that can be easily assembled and disassembled on the second component helping the maintenance.
In another preferred embodiment the sealing part comprises a laminar-shaped section to help its join to the second component and a wedge-shaped section to fill said gap, and the second component comprises a joggled area in the joint with the first component to maintain the continuity of the aircraft aerodynamic contour along the whole second component where said sealing part with said laminar-shaped section is joined to the second component. Hereby it is achieved a sealing part that also provides a protection of the edge of the second component in the join area.
In another aspect, the above-mentioned objectives are met by a procedure to carry out the aforementioned joint arrangement comprising steps of: a) join the sealing part to the second component; b) join the second component to the first component. Hereby it is achieved a procedure that helps the assembly of said first and second components.
One particular field of application of the present invention is the interface between a skin and a leading edge panel or a trailing edge panel in an aircraft lifting surface such as a wing or an horizontal tail plane.
Another particular field of application of the present invention is the interface between circumferential sections of an aircraft fuselage.
This invention is applicable to interfaces between composite parts and also to interfaces between metallic parts.
Other characteristics and advantages of the present invention will be clear from the following detailed description of embodiments illustrative of its object in relation to the attached figures.
A detailed description of the invention for an interface arrangement between a wing skin and a wing leading edge panel follows.
The main structure for aircraft lifting surfaces consists of a leading edge, a torsion box, a trailing edge, a root joint and a tip. A torsion box structurally consists of spars, ribs and upper and lower skins with several stringers. The upper and lower skins are joined to the leading edge and the trailing edge panels forming the upper and lower wing aerodynamic contour.
This interface arrangement creates a gap 25 of width W and height H which can not be sealed satisfactorily using an aerodynamic smoothing sealant when H is bigger than 10 mm. On the other hand, said sealant raise several maintenance problems due to certain defects (particularly cracking) or to its detachment from the wing skin 11.
According to the present invention, the gap 25 is filled with a sealing part 31 (see
The sealing part 31, which in a preferred embodiment is made of an elastomeric material, can therefore be dismounted when needed and replaced by a new sealing part 31 facilitating thus its maintenance.
The sealing part 31 is made with a suitable shape for filling the gap 25 (whose shape is determined by the geometric features of the wing skin 11 in the intermediate zone between said first and second areas 13, 17) taking into account the tolerance margins in the assembly of the leading edge panel 21 with the wing skin 11. It is therefore possible to have several sets of sealing parts 31 for different tolerance and manufacture margins to choose the right one in the assembly line.
In a preferred embodiment, the gap 25 filled with said sealing part 31 has a width W comprised between 10-15 mm and a height H greater than 3 mm.
In the preferred embodiment shown in
The sealing part 31 according to this embodiment fills the gap 25 and provides an additional protection to the edge of the leading edge panel 21 against strikes or impacts; if they occur it is the sealing part 31 and not the leading edge panel 21 the part to be repaired.
The procedure to carry out the joint arrangement of the present invention comprises a first step where the sealant part 31 is joined to the leading edge panel 21 previously to the step of joining the leading edge panel 21 to the wing skin 11. Their assembly is therefore facilitated when compared with a joint arrangement using an aerodynamic smoothing sealant.
Although the present invention has been fully described in connection with preferred embodiments, it is evident that modifications may be introduced within the scope thereof, not considering this as limited by these embodiments, but by the contents of the following claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 201031768 | Nov 2010 | ES | national |
