Apparatus for attaching an aerodynamic function film and method of use of the apparatus

Abstract

The invention relates to a device for attaching an aerodynamic functional film (14.1-5) to a surface (4) of a body (1) around which a flow occurs, and to a method of using such a device. The device comprises a self-adhesive, removable positioning film (11) having positioning aids (12) for precisely positioning the positioning film (11) on the surface (4) of the body (1) around which a flow occurs, and at least one application zone (13.1-5) for the aerodynamic functional film (14.1-5) to be applied. The device is used by: a) applying the positioning aids (11) of the device to the surface (4) of the body (1) around which a flow occurs in the positions defined by the positioning aids (12); b) applying the aerodynamic functional film (14.1-5) to the surface (4) of the body (1) around which a flow occurs in the application zones (13.1-5) of the positioning film (11); and c) removing the positioning film (11).

Description

TECHNICAL FIELD

[0001] The invention relates to a device for attaching an aerodynamic functional film to a surface of a body through which an air flow passes and to a method of using such a device. BACKGROUND

[0002] Aerodynamic functional films are known from the prior art in different embodiments and areas of application and are generally used to reduce the wall shear stress on a surface of a body through which an air flow passes. For this purpose, the aerodynamic functional films generally have a microstructured surface.

[0003] A common microstructure is the so-called riblet structure, which has very small ribs extending essentially in the main flow direction. The riblet structure is located, for example, on the outside of an aircraft, but also on the rotor blades of a wind turbine, on the hull plates of a ship or on the outer surface of a high-speed train. Such structures are likewise used on the inside of, for example, a pipe.

[0004] In order to enable the aerodynamic functional film and in particular the riblet structure to reduce the wall shear stress to the greatest possible extent, it is necessary to align the film as precisely as possible with respect to the local main flow direction, i.e. the direction in which the air flow above the surface in the region of the film is expected to pass through primarily. In an aircraft, the main flow direction on the outer wall, which can locally vary well over the entire outer wall of the aircraft, is the result of the flow around the aircraft, for example in cruising flight.

[0005] In the prior art, the aerodynamic functional films in the form of standard, approximately rectangular or square patches are bonded directly adhesively to the body through which an air flow passes. In this respect, they have to be positioned manually on the body and, if appropriate, they are further processed by being cut to size. In order to achieve the positioning as precisely as possible, complex and in particular lengthy initial measurements are required. In a vehicle such as an aircraft or a high-speed train, this means that the downtime for attaching the aerodynamic functional films is undesirably long. SUMMARY

[0006] It is an object of the invention to improve the attachment of an aerodynamic functional film to a surface of a body through which an air flow passes, so that the disadvantages known from the prior art no longer occur or only to a reduced extent.

[0007] This object is achieved by the device according to the invention and by the method of using the device according to the invention.

[0008] The present invention therefore relates to a device for attaching an aerodynamic functional film to a surface of a body around which an air flow passes, comprising a self-adhesive, releasable positioning film, which has positioning aids for precisely positioning the positioning film on the surface of the body around which an air flow passes, and which has at least one application zone for an aerodynamic functional film to be applied.

[0009] The present invention also relates to a method for attaching an aerodynamic functional film to a surface of a body around which an air flow passes, using a positioning aid according to the invention, having the following steps:

[0010] a) applying the positioning film of the device to the surface of the body around which an air flow passes in a position predefined by the positioning aids;

[0011] b) applying the aerodynamic functional film to the surface of the body around which an air flow passes in the application zone of the positioning film; and

[0012] c) removing the positioning film.

[0013] Within the meaning of the present invention, a film is "self-adhesive" if its position and positioning are substantially fixed after application to the surface. It is not excluded here that the self-adhesive film can also be removed again from the surface, if necessary, preferably non-destructively. For example, in order to produce a static adhesive connection with the surface, the self-adhesive film can be self-adhesive or can be magnetic. The film can be self-adhesively connected to the surface over its entire surface area or selectively.

[0014] The present invention has recognised that the use of a device in the form of a positioning film can greatly simplify and accelerate the attachment of an aerodynamic functional film to a surface in the correct position and alignment without reducing the positioning accuracy of the aerodynamic functional film in the process. The positioning film is configured as a releasable self-adhesive film, for example a sticky film, for positioning one or more aerodynamic functional films on the surface of a body. The positioning film is temporarily attached to the same surface for positioning one or more aerodynamic functional films on the surface of a body, but is also removed again after the one or more aerodynamic functional films have been applied.

[0015] In this respect, the positioning film has positioning aids which allow the positioning film to be precisely positioned on the surface of the body around which an air flow passes. The positioning aids can be edges of the positioning film which come into contact or are at least aligned with protrusions or the like on the surface of the body around which an air flow passes. In addition or as an alternative, markings can also be provided on the positioning film which are intended to be aligned with specific predetermined features, for example screws, holes or joints, on the surface of the body around which an air flow passes. If the positioning film is applied to the surface of the body around which an air flow passes in accordance with the positioning aids, correct positioning of the positioning film is ensured.

[0016] Correct positioning of the positioning film also ensures that at least one application zone of the positioning film is correctly positioned on the surface of the body surrounded by the air flow through. In this respect, the application zone is the zone of the surface of the body surrounded by the air flow through to which the aerodynamic functional film is to be applied or to which it is applied.

[0017] In a first configuration of the application, at least one self-adhesive aerodynamic functional film is arranged in the region of at least one application zone on the self-adhesive side of the positioning film, for example provided with adhesive, which adheres to the surface of the body surrounded by the air flow through upon attachment of the positioning film and remains on the surface of the body surrounded by the air flow through upon subsequent removal of the positioning film. In other words, in the initial state, the aerodynamic functional film and the positioning film form a multi-layer unit which makes it possible for the aerodynamic functional film to be directly adhesively bonded to the surface when the positioning film is ensured to be applied in the correct position by the positioning aid. In this respect, the position of the aerodynamic functional film on the surface can be directly determined from the position of the film on the positioning film. It is of course also possible to provide more than one application zone and / or aerodynamic functional film on the positioning film in order to provide aerodynamic functional films for a plurality of regions of the surface of the body surrounded by the air flow through.

[0018] If the positioning film is applied to the surface of the body surrounded by the air flow through together with one or more aerodynamic functional films in one or more application zones, there is a corresponding adhesive connection between the positioning film and the surface, in particular remote from the application zone, and between the one or more aerodynamic functional films and the surface, in the region of the application zone, wherein in particular the adhesive connection between the positioning film and the surface is releasable. In contrast, the connection between the one or more aerodynamic functional films and the surface is configured substantially so as not to be easily releasable. If this material-bonded connection between the one or more aerodynamic functional films and the surface of the body surrounded by the air flow through is not releasable or at least has a relatively high adhesion, it is possible for the one or more aerodynamic functional films to be held in the desired position on the surface of the body surrounded by the air flow through in the event of the positioning film being pulled away from the surface.

[0019] Preferably, when the aerodynamic functional film has to be aligned on the surface of the body surrounded by the air flow through, for example because it involves a rib film to be aligned in the main flow direction, if the aerodynamic functional film is arranged on the positioning film, this makes it possible for the aerodynamic functional film to have the desired alignment after the aerodynamic functional film is attached and the positioning film is subsequently removed.

[0020] In at least one of these aerodynamic functional films, openings in the form of cutouts and / or slits can be provided for keeping free positions on the surface of the body through which there is a flow of air. If the aerodynamic functional film is arranged, for example, in the region of a flap on the surface of the body through which there is a flow of air, the functionality of the flap can still be ensured by a plurality of suitable slits in the aerodynamic functional film. Other orifices or sensors on the surface of the body through which there is a flow of air can also be kept free by suitable openings in the aerodynamic functional film.

[0021] In a second configuration of the application, an application window is provided in the region of at least one application zone, within which application window the at least one aerodynamic functional film can be applied to the surface of the body through which there is a flow of air after attachment of the releasable adhesive film. The application window is an opening in the positioning film which, after the positioning film has been attached to the surface of the body through which there is a flow of air, specifies the position of the aerodynamic functional film to be applied in a further step, and wherein the aerodynamic functional film can be applied directly. If the aerodynamic functional film is applied completely within one or more application windows, the positioning film can be removed again.

[0022] Preferably, the positioning film has an alignment aid in the region of the application window for aligning the aerodynamic functional film to be applied. The alignment aid may, for example, be a marking on the positioning film which specifies how the aerodynamic functional film to be applied must be aligned, for example because the aerodynamic functional film is a rib film to be aligned in the local main flow direction.

[0023] Furthermore or as an alternative, the contour of the at least one application window can match the shape of the aerodynamic functional film to be attached within the at least one application window, wherein the contour of the at least one application window is preferably asymmetrical. In other words, the contour of the application window thus preferably corresponds to the contour of the film to be applied, so that said film can be applied to the surface of the body through which there is a flow of air through the application window only in a few possible alignments, as a result of which the risk of misalignment of the aerodynamic functional film can be reduced. This can also be the case whenever a plurality of film portions are applied substantially through the application window in order to integrally form a desired region with an aerodynamic effect on the surface of the body through which there is a flow of air, to the extent that the film portions forming the contour of the region can each be positioned only in a few positions within the application window.

[0024] If the contour of the application window and thus preferably the contour of the film to be applied through the application window also has an asymmetric configuration, the risk of misalignment of the aerodynamic functional film can be almost completely eliminated. In this case, the film can be applied through the application window in alignment only in a single instance. This can also apply again whenever a plurality of film portions are applied substantially through the application window in order to form the desired region with the aerodynamic effect on the surface of the body through which there is an air flow.

[0025] It is also possible to use a second positioning film designed according to the first configuration of the application instead of an aerodynamic functional film having a contour which matches the edge of the application window directly. The positioning aid of the second positioning film on which the final aerodynamic functional film is arranged can then match the edge of the application window of the (first) positioning film.

[0026] In addition or as an alternative, the positioning film according to the application can also be used for positioning so-called cutting tapes - also known as knifeless tapes.

[0027] The respective cutting tape is usually applied to the surface of the body through which there is an air flow before the aerodynamic functional film. After the aerodynamic functional film has been applied, the cutting tape is pulled out, as a result of which the aerodynamic functional film is cut to size along the cutting tape. The so-called cutting tape thus makes it possible to easily match the aerodynamic functional film to the interrupted surface, for example through an entry opening on the fuselage of an aircraft.

[0028] In order to precisely position the cutting tape, they can be applied to the surface of the body through which there is an air flow using the positioning film according to the application.

[0029] In this case, at least one cutting tape is preferably applied to the surface of the body through which there is an air flow at the edge of the application region. After the positioning film has been pulled out, the cutting tape remains on the surface of the body through which there is an air flow. The aerodynamic functional film can then be applied. Subsequently, the aerodynamic functional film is cut at the location overlapping the cutting tape by pulling out the cutting tape.

[0030] The method of use according to the application is explained with reference to the above embodiments. BRIEF DESCRIPTION OF DRAWINGS

[0031] The application will now be described by way of example on the basis of advantageous embodiments with reference to the accompanying drawings, in which:

[0032] Figure 1 : a schematic plan view of an aircraft wing which is to be provided with an aerodynamic functional film in a specific region is shown;

[0033] Figure 2: a set is shown, which comprises a device for attaching an aerodynamic functional film to a wing of an aircraft according to Figure 1 ;

[0034] Figures 3a to 3c : a schematic view of a method of using a set for attaching an aerodynamic functional film to a wing of an aircraft according to Figure 2 ; Figure 1

[0035] Figures 4a to 4b : a schematic view showing details of a variant of the attachment of an aerodynamic functional film using a device from Figure 2 . DETAILED DESCRIPTION

[0036] Figure 1 A plan view of a wing 1 of a passenger aircraft 2 in the form of a body surrounded by an air flow is shown schematically. On the wing 1 a marking 3 is provided, which identifies a region 4 of the wing 1 that can be accessed. Precisely in this tread region 4 there are provided areas 5.1 - 5.5, which are provided with an aerodynamic functional film, in particular a rib film. In the area 5.3 there extends a flap 6, which when opened allows access to the suspension of an engine 7. The function of the flap 6 must not be adversely affected by the aerodynamic functional film to be attached in the area 5.3 under discussion.

[0037] Figure 2 A set 10 is shown, with which an aerodynamic functional film can be quickly and positionally precisely attached in the desired areas 5.1 - 5.5 on the wing 2.

[0038] The set 10 comprises a positioning film 11, the top side of which is shown and which is self-adhesive on the bottom side, so that the positioning film 11 can also be detached again from the surface to which it is attached without residue. In the exemplary embodiment shown, the positioning film 11 is self-adhesive, but fundamentally it can also be statically or magnetically self-adhesive. The following embodiments with regard to the self-adhesive properties of the positioning film 11 apply analogously.

[0039] The positioning film 11 has three edges in terms of a positioning aid 12, which in the state of use can be aligned with the marking 3 of the airfoil tread surface 4, the positioning film 11 shown is intended for this airfoil tread surface and this airfoil tread surface is shown as in Figure 1 , the result of which is to ensure the correct alignment of the positioning film 11.

[0040] ​Furthermore, the positioning film 11 also has a plurality of application zones 13.1-13.5, which correspond to the regions 5.1-5.5 of the wing 1 that are to be provided with an aerodynamic functional film. The application zones 13.1-13.5 are respectively in the shape of the regions 5.1-5.5, and coincide with the regions when the positioning film 11 is properly attached to the wing 1.

[0041] The application zone 13.1 is in the form of an application window, i.e. an opening in the positioning film 11 with an asymmetric profile. The application zone 13.1 is provided with an aerodynamic functional film 14.1, which can be applied to the wing 1 only in a predetermined position within the application window. The application window thus also directly predefines the alignment of the aerodynamic functional film 14.1 on the wing 1, which is the reason why the film 14.1 has a rib structure in the region 5.1 that corresponds to the intended main flow direction.

[0042] The application zone 13.2 is also in the form of an application window, i.e. an opening in the positioning film 11. However, due to the size of the application zone 13.2, the main flow direction over this region is no longer considered constant. To take this into account, two aerodynamic functional films 14.2', 14.2'' are provided, which together completely cover the region 5.2, but whose rib structures are not aligned. Nonetheless, to be able to achieve joint application of the two films 14.2', 14.2'', a second positioning film 15 is provided, on the self-adhesive bottom side of which the two films 14.2', 14.2'' are arranged in correct alignment relative to each other. The adhesive layer of the films 14.2', 14.2'' is provided on the side facing away from the positioning film 15. The use of the second positioning film 15 for applying the two aerodynamic functional films 14.2', 14.2'' will be explained in more detail below.

[0043] In the application zone 13.3, the positioning film 11 is continuous and has no openings. For this purpose, the aerodynamic functional film 14.3 is arranged directly on the bottom side of the positioning film 11, the adhesive layer of which is arranged on the side facing away from the positioning film 11. The aerodynamic functional film 14.3 has a plurality of slots 16, which correspond to the boundaries of the flap 6 on the wing 1, with the result that the flap 6 can still be opened even after the aerodynamic functional film 14.3 has been attached in the region 5.3. The attachment of the film 14.3 on the wing 1 will be described in more detail below.

[0044] The application zones 13.4 and 13.5 are rectangular application windows in the positioning film 11, which correspond to the areas 5.4 and 5.5, respectively. For these application zones 13.4 and 13.5, a plurality of smaller portions of the aerodynamic functional film 14.4 / 5 of standard size are provided, which areas 5.4 and 5.5 are to be equipped in a tiling manner. In order to ensure that the plurality of portions of the aerodynamic functional film 14.4 / 5 are applied in the areas 5.4 and 5.5 in the correct orientation to the wing 1, an alignment aid 17 is provided on the positioning film 11, on the basis of which the aerodynamic functional film 14.4 / 5 to be applied can be aligned.

[0045] Reference will now be made to Figures 3a to 3c the use of the device 10 according to Figure 2 to attach the aerodynamic functional films 14.1 to 14.5 in the areas 5.1 to 5.5 provided for this purpose on the wing 1 of the aircraft 2 according to Figure 1 .

[0046] In the first step shown in Figure 3a , the positioning film 11 is adhesively bonded to the wing 1, it being noted that the edges 12 of the positioning film 11 provided for this purpose correspond exactly to the markings 3 of the zones 4 on the wing 1. If the positioning film 11 is applied to the wing 1 correspondingly exactly, the application zones 13.1 to 13.5, which correspond to the areas 5.1 to 5.5, respectively, are provided for the attachment of the aerodynamic functional films 14.1 to 14.5. In the area 5.3, the film 14.3 provided for this purpose is even already applied or adhesively bonded directly and in the correct position and orientation to the wing 1 when the positioning film 11 is attached. In this case, the slot 16 in the film 14.3 corresponds to the edge of the flap 6.

[0047] In the remaining areas of the areas 5.1, 5.2, 5.4 and 5.5, the respective films 14.1, 14.2, 14.4 / 5 are applied in subsequent steps (cf. Figure 3b ).

[0048] In the area 5.1, the film 14.1 is adhesively bonded within the application zone 13.1 in the only possible orientation as a result of the asymmetrical preliminary cut. The same applies to the films 14.2' and 14.2'' fastened to the second positioning film 15. The second positioning film 15 directly positions the films 14.2' and 14.2'' correctly by being applied to the wing 1 in the position and orientation indicated by the possible positioning aid with respect to the application zone 13.2.

[0049] In the regions 5.4 and 5.5, these individual film portions 14.4 / 5 are adhesively bonded one after the other, as a result of which a continuous region of the aerodynamic functional film 14 is ultimately produced, which fills the entire region 5.4 and 5.5. When attaching the film portions 14.4 / 5, it should be noted that the film portions 14.4 / 5 are oriented according to the alignment aids 17.

[0050] Finally, the positioning film 11, 15 is removed, and the aerodynamic functional film 14.1-5 remains on the wing 1.

[0051] Of course, these aerodynamic functional films 14.1 to 14.5 can still be reworked after the final adhesion to the wing 1 and before or after the removal of the positioning film 11, 15, for example in order to ensure the functioning of additional flaps or sensors (not shown).

[0052] Figure 4a 、 Figure 4b The attachment and detachment of the positioning film 11, 15 is shown, wherein the aerodynamic functional film 14.2 / 3 is arranged directly on this positioning film.

[0053] As shown in Figure 4a , the positioning film 11 / 15 with its adhesive layer 11' / 15' (designed to be releasable) is adhesively bonded to the region 4 of the wing 1, on which the aerodynamic functional film 14.2 / 3 is arranged directly in the part that ultimately forms the application region 13.3. The aerodynamic functional film 14.2 / 3 is releasably connected to the positioning film 11 / 15 by means of the adhesive layer 11' / 15', which is additionally provided for fastening to the wing 1, and the film 14.2 / 3 itself has an adhesive layer 18 and is irreleasably connectable to the wing 1 by means of this adhesive layer.

[0054] The multi-layer arrangement of the positioning film 11 / 15 and the aerodynamic functional film 14.2 / 3 is attached in a known manner, for example, as shown in Figure 4a , by gradually pulling out the non-adhesive carrier 19 and pressing the arrangement onto the wing 1.

[0055] If the positioning film 11 / 15 is completely attached, it can be removed again. Due to the releasable adhesive layer 11' / 15', this positioning film 11 / 15 can be removed without residue, the aerodynamic functional film 14.2 / 3 remaining on the wing 1 due to the non-releasable adhesive layer 18.

Claims

1. A kit of parts for attaching an aerodynamic functional film to a surface (4) of a body (1) around which an air flow passes, comprising: a device for attaching an aerodynamic functional film to a surface of the body, the device comprising a self-adhesive, releasable positioning film (11) having positioning aids (12) for precisely positioning the positioning film (11) on a surface (4) of the body (1) around which an air flow passes, and having at least one application zone for the aerodynamic functional film to be applied; and at least one self-adhesive aerodynamic functional film, which is arranged in the area of at least one application zone on the side of the positioning film (11) provided with adhesive (11'), which, when the positioning film (11) is attached, adheres to a surface (4) of the body (1) around which an air flow passes, and which, when the positioning film (11) is subsequently removed, remains on a surface (4) of the body (1) around which an air flow passes.

2. The kit of parts according to claim 1, characterized in that the aerodynamic functional film (14.3) is arranged on the positioning film (11) in such a way that, after the aerodynamic functional film (14.3) is attached and the positioning film (11) is subsequently removed, the desired alignment of the aerodynamic functional film (14.3) is achieved, when the aerodynamic functional film (14.3) needs to be aligned on a surface (4) of the body (1) around which an air flow passes.

3. The kit of parts according to claim 1 or 2, characterized in that the aerodynamic functional film (14.3) has a plurality of openings and / or slots (13) in the form of cutouts for keeping free positions on a surface (4) of the body (1) around which an air flow passes.

4. A method of using the kit of parts according to any one of claims 1 to 3 for attaching an aerodynamic functional film to a surface (4) of a body (1) around which an air flow passes, having the following steps: a) applying the positioning film (11) of the device to a surface (4) of the body (1) around which an air flow passes in a position predefined by positioning aids (12); b) applying the aerodynamic functional film to a surface (4) of the body (1) around which an air flow passes in the application zone of the positioning film (11); and c) removing the positioning film (11).

5. The method of use according to claim 4, characterized in that steps a) and b) are carried out simultaneously.

6. The method of use according to claim 4 or 5, characterized in that the aerodynamic functional film is a rib film, and / or the body around which an air flow passes is an aircraft (2) or an aircraft wing.

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