AIRCRAFT STRUCTURE COMPONENT FOR LAMINAR FLOW

Abstract

An aircraft structure component for laminar flow, the aircraft structure component having an outer skin with an aerodynamic surface, wherein the aerodynamic surface has a leading edge portion and a downstream portion adjacently downstream from the leading edge portion, and wherein the downstream portion of the aerodynamic surface includes a paint layer that is not present in the leading edge portion, so that an edge line is formed between the leading edge portion and the downstream portion by the beginning paint layer. An object, to provide an aircraft structure component that allows for a reduced aerodynamic drag, is achieved in that the edge line has a ramp-shaped cross section, wherein the thickness of the paint layer increases from a starting point over a predetermined ramp length to a saturation point where the full thickness of the paint layer is reached.

Claims

1. An aircraft structure component for laminar flow, the aircraft structure component having an outer skin with an aerodynamic surface, wherein the aerodynamic surface has a leading edge portion and a downstream portion adjacently downstream from the leading edge portion, and wherein the downstream portion of the aerodynamic surface comprises a paint layer or a foil layer that is not present in the leading edge portion, so that an edge line is formed between the leading edge portion and the downstream portion by the beginning paint layer or foil layer, and wherein the edge line has a ramp-shaped cross section, wherein a thickness of the paint layer or foil layer increases from a starting point over a predetermined ramp length to a saturation point where a full thickness of the paint layer or foil layer is reached.

2. The aircraft structure component according to claim 1, wherein the ramp length is at least as great as the full thickness of the paint layer or foil layer at the saturation point.

3. The aircraft structure component according to claim 1, wherein the ramp-shaped cross section of the edge line has a linear course, so that thickness of the paint layer or foil layer increases linearly from the starting point to the saturation point.

4. The aircraft structure component according to claim 1, wherein the ramp-shaped cross section of the edge line has a curved course, so that the thickness of the paint layer or foil layer increases nonlinearly from the starting point to the saturation point with an increasing slope or a decreasing slope.

5. The aircraft structure component according to claim 4, wherein the ramp-shaped cross section of the edge line has a double-curved course, so that the thickness of the paint layer or foil layer increases from the starting point to the saturation point with an increasing slope followed by a decreasing slope.

6. The aircraft structure component according to claim 1, wherein the edge line has a straight course along the aerodynamic surface.

7. The aircraft structure component according to claim 6, wherein an angle between the course of the edge line and a direction of incoming flow is greater than 30.

8. The aircraft structure component according to claim 1, wherein the edge line has a periodically curved course along the aerodynamic surface.

9. The aircraft structure component according to claim 8, wherein the edge line has a sinusoidal course along the aerodynamic surface.

10. The aircraft structure component according to claim 8, wherein an angle between a direction of incoming flow and a tangent to an inflection point present in the course of the edge line, is greater than 30.

11. The aircraft structure component according to claim 8, wherein all angles between a direction of incoming flow and tangents to the inflection points present in the course of the edge line, are equally great.

12. The aircraft structure component according to claim 8, wherein the course of the edge line defines a plurality of fore peaks and a plurality of aft peaks with respect to a direction of the incoming flow, wherein, while at an aft peak the ramp length is as great as full thickness of the paint layer or foil layer at the saturation point, at an adjacent fore peak the ramp length is between twice and 20 times as great as full thickness of the paint layer or foil layer at the saturation point.

13. The aircraft structure component according to claim 12, wherein, while at an aft peak the ramp length is as great as the full thickness of the paint layer or foil layer at the saturation point, at an adjacent fore peak the ramp length is between 5 and 10 times as great as the full thickness of the paint layer or foil layer at the saturation point.

14. A method for producing an aircraft structure component for laminar flow, the method comprising: providing an aircraft structure component having an outer skin with an aerodynamic surface, wherein the aerodynamic surface has a leading edge portion and a downstream portion adjacently downstream from the leading edge portion; applying a paint layer or foil layer onto the downstream portion of the aerodynamic surface without applying the paint layer or foil layer also to the leading edge portion, so that an edge line is formed between the leading edge portion and the downstream portion by the beginning paint layer or foil layer; and processing the paint layer or foil layer along the edge line, such that the edge line has a ramp-shaped cross section, wherein a thickness of the paint layer or foil layer increases from a starting point over a predetermined ramp length to a saturation point where the full thickness of the paint layer or foil layer is reached.

15. The method according to claim 14, wherein the paint layer or foil layer is processed along the edge line by removing material of the paint layer or foil layer.

16. The method according to claim 15, wherein the material of the paint layer or foil layer is removed by grinding, polishing or laser treatment, such as laser ablation.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Preferred embodiments of the present disclosure are described hereinafter in more detail by example drawings, where:

[0019] FIG. 1 is a perspective view of an aircraft structure component according to a first embodiment of the present disclosure;

[0020] FIG. 2 is a schematic cross-sectional view of the aircraft structure component of FIG. 1, wherein the edge line has a linear ramp-shaped cross section;

[0021] FIG. 3 is a schematic cross-sectional view of a second embodiment of the aircraft structure component according to the disclosure herein, wherein the edge line has a double-curved ramp-shaped cross section;

[0022] FIG. 4 a schematic top view of the aircraft structure component of FIG. 1 relative to the incoming flow, wherein the edge line has a straight course; and

[0023] FIG. 5 a schematic top view of a third embodiment of an aircraft structure component according to the present disclosure, wherein the edge line has a sinusoidal course.

DETAILED DESCRIPTION

[0024] In FIG. 1, a first embodiment of an aircraft structure component 1 for laminar flow is shown, in the present embodiment a slat. The aircraft structure component 1 has an outer skin 3 with an aerodynamic surface 5 adapted to be in contact with an aerodynamic flow. The aerodynamic surface 5 has a leading edge portion 7 that is directed towards the incoming flow 9 of an associated aircraft during flight and that is, thus, adapted for a laminar flow. The aerodynamic surface 5 further has a downstream portion 11 adjacently downstream from the leading edge portion 7 with respect to the incoming flow 9. The downstream portion 11 of the aerodynamic surface 5 comprises a paint layer 13 that is not present in the unpainted leading edge portion 7, so that an edge line 15 in the form of a thickness jump is present between the leading edge portion 7 and the downstream portion 11 by the beginning paint layer 13, wherein the edge line 15 extends transverse the incoming flow 9. As shown in FIG. 2, the edge line 15 has a ramp-shaped cross section 17 along the incoming flow 9, wherein the thickness of the paint layer 13 increases from a starting point 19 where the paint layer begins over a predetermined ramp length 21 in the direction of the incoming flow 9 to a saturation point 23 where the full thickness 25 of the paint layer 13 is reached.

[0025] As also shown in FIG. 2, the ramp length 21 is about three times as great as the full thickness 25 of the paint layer 13 at the saturation point 23. FIG. 2 also shows that the ramp-shaped cross section 17 of the edge line 15 has a linear course 27, so that the thickness of the paint layer 13 increases linearly from the starting point 19 to the saturation point 23.

[0026] In an alternative embodiment shown in FIG. 3, the ramp-shaped cross section 17 of the edge line 15 has a curved course, in particular a double-curved course 29, so that the thickness of the paint layer 13 increases from the starting point 19 to the saturation point 23 with an increasing slope 31 followed by a decreasing slope 33.

[0027] As shown in FIG. 4, the edge line 15 has a straight course 35 along the aerodynamic surface 5 in a direction transverse the incoming flow 9. The angle 37 between the course of the edge line 15 and the direction of the incoming flow 9 is greater than 30 degrees, in the present embodiment about 60 degrees.

[0028] According to an alternative embodiment shown in FIG. 5, the edge line 9 has a periodically curved course, in particular a sinusoidal course 39 along the aerodynamic surface 5 transverse the incoming flow 9. The angle 40 between the direction of the incoming flow 9 and a tangent 41 to any inflection point 43 present in the course of the edge line 15 is greater than 30 degrees, in the present embodiment between 30 and 45 degrees. It might also be preferred that all angles 40 between the direction of the incoming flow 9 and the tangents 41 to the inflection points 43 present in the course of the edge line 15 are equally great. In the embodiment shown in FIG. 5, the course of the edge line 15 defines a plurality of fore peaks 45 and a plurality of aft peaks 47 with respect to the direction of the incoming flow 9. While at an aft peak 47 the ramp length 21 is as great as the full thickness 25 of the paint layer 13 at the saturation point 23, at an adjacent fore peak 45 the ramp length 21 is between twice and twenty times, in the present embodiment five times as great as the full thickness of the paint layer 13 at the saturation point 23.

[0029] The aircraft structure components 1 as shown in FIGS. 1 through 5 can be produced in the following manner: First, an aircraft structure component 1 having an outer skin 3 with an aerodynamic surface 5 is provided, wherein the aerodynamic surface 5 has a leading edge portion 7 and a downstream portion 11 adjacently downstream from the leading edge portion 7 with respect to the incoming flow 9. Subsequently, a paint layer 13 is applied onto the downstream portion 11 of the aerodynamic surface 5 without applying the paint layer 13 also to the leading edge portion 7, so that an edge line 15 is formed between the leading edge portion 7 and the downstream portion 11 by the beginning paint layer 13. Finally, the paint layer 13 is processed along the edge line 15 by removing the material of the paint layer 13 through grinding, polishing or laser treatment, such that the edge line 15 has a ramp-shaped cross section 17 along the incoming flow 9, where the thickness of the paint layer 13 increases from a starting point 19 over a predetermined ramp length 21 to a saturation point 23, where the full thickness 25 of the paint layer 13 is reached.

[0030] 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, an 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.