Leading-edge slat for an aircraft

Abstract

A leading-edge slat for an aircraft is proposed, which includes a front skin), a back skin, a spar and an air inlet for receiving air at an elevated temperature for de-icing or anti-icing. In the slat, at least one air chamber is created, which is supplied with said air. A first portion of the back skin is attached to the spar at a distance to the bottom section, wherein a second portion of the back skin is attached to the top section. Thereby, a region in front of the fixed leading edge is created, into which air from air outlets integrated into the back skin can be exhausted outside of the slat.

Claims

1. An aircraft leading-edge slat, comprising: a slat body having a front skin; a back skin; a spar; and an air inlet, wherein the front skin is curved about at least 120° around a spanwise axis to form a bottom section and a top section, wherein a leading edge of the slat body is arranged between the bottom section and the top section, and wherein the spar extends from the bottom section to the top section, wherein a first portion of the back skin is attached to the spar at a distance to the bottom section, wherein a second portion of the back skin is attached to the top section, wherein the back skin is bent away from the spar and comprises a directly adjacent outlet portion extending in a spanwise direction and directly facing the bottom section, wherein the front skin, the back skin and the spar enclose at least one air chamber in fluid communication with the air inlet, and wherein the outlet portion comprises a plurality of air outlets for letting air from the at least one air chamber exhaust through the air outlets.

2. The aircraft leading-edge slat of claim 1, wherein the outlet portion is substantially flat.

3. The aircraft leading-edge slat of claim 1, wherein each of the air outlets are configured to comprise a through-flow direction axis, wherein the through-flow direction axis and the spar enclose an angle of 45° at a maximum.

4. The aircraft leading-edge slat of claim 1, wherein the outlet portion is connected to a central portion of the spar, and wherein the central portion extends in a range of 20 percent above and 45 percent below the half height of the spar.

5. The aircraft leading-edge slat of claim 1, wherein the first portion is configured as a flange surface.

6. The aircraft leading-edge slat of claim 5, wherein the first portion extends along the spar towards the bottom section.

7. The aircraft leading-edge slat of claim 1, wherein the back skin is bent away from the spar through a kink.

8. The aircraft leading-edge slat of claim 1, wherein the back skin is bent away from the spar through a curved transition section.

9. The aircraft leading-edge slat of claim 8, wherein the curved transition section comprises a constant radius of curvature.

10. The aircraft leading-edge slat of claim 1, wherein the back skin is bent towards the front skin at a region directly adjacent to the outlet portion opposite to the spar.

11. An aircraft wing, having a fixed leading edge and a leading-edge slat according to claim 1, wherein the leading-edge slat is movable between a retracted position directly forward the fixed leading edge and at least one extended position at a further distance to the fixed leading edge.

12. The aircraft wing of claim 11, wherein the air outlets are configured to exhaust the air in a region in front of the fixed leading edge in the retracted position of the leading-edge slat.

13. The aircraft wing of claim 11, wherein the air outlets are arranged in front of the fixed leading edge.

14. An aircraft having at least one aircraft wing of claim 11, wherein the air inlet is in fluid communication with a source of heated air.

15. The aircraft of claim 14, further comprising at least one turbofan engine having at least one bleed air port, wherein the air inlet is in fluid communication with the at least one bleed air port, such that bleed air delivered by the at least one turbofan engine is the source of heated air.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other characteristics, advantages and potential applications of the present invention result from the following description of the exemplary embodiments illustrated in the figures. In this respect, all described and/or graphically illustrated characteristics also form the object of the invention individually and in arbitrary combination regardless of their composition in the individual claims or their references to other claims. Furthermore, identical or similar objects are identified by the same reference symbols in the figures.

(2) FIG. 1 shows a leading-edge slat and a fixed leading edge of a wing in a sectional view.

(3) FIG. 2 shows the leading-edge slat from a rear view.

(4) FIG. 3 shows a slightly modified leading-edge slat in a three-dimensional view.

(5) FIG. 4 shows a detail of an open region between the leading-edge slat and the fixed leading edge in a lateral view.

(6) FIG. 5 shows an aircraft.

DETAILED DESCRIPTION

(7) FIG. 1 shows a fixed leading edge 2 of a wing 4 and a leading-edge slat 6 in front of the fixed leading edge 2. In this illustration, the leading-edge slat 6 is in its retracted position. During certain flight phases, the leading-edge slat 6 can be moved to extended positions in a larger distance to the fixed leading edge 2. The leading-edge slat 6 comprises a slat body 8 having a front skin 10, a back skin 12, a spar 14 and an air inlet 16. The front skin 10 is significantly curved about an angle β of approximately 150° as an example and constitutes a forward delimitation of the wing 4 if the leading-edge slat is in the retracted position. In a region of strongest curvature, a leading edge 18 is located. During flight, the front skin 10 is exposed to an air flow.

(8) The front skin 10 forms a bottom section 20 and a top section 22, wherein the leading edge 18 is arranged therebetween. The spar 14 extends from the bottom section 20 to the top section 22. Consequently, a first air chamber 24 is created between the spar 14 and the front skin 10. Here, a tube 26, which may be a piccolo tube, extends along the leading edge 18. The piccolo tube is a tube having a plurality of openings in its circumferential surface. Air from an interior space of the piccolo tube can be discharged through the openings to the outside of the piccolo tube. Hence, air at an elevated temperature can be supplied into the tube 26 through the air inlet 16, such that it flows through the tube 26 into the first air chamber 24. As a result, the front skin 10 is heated up for conducting a de-icing or anti-icing function.

(9) The back skin 12 comprises a first portion 28, which is attached to the spar 14. Exemplarily, the first portion 28 is arranged in a central portion 30 of the spar 14. From there, the back skin 12 exemplarily extends to an upper end 32 of the front skin 10 to form a second portion 31, which is exemplarily attached to the front skin 10. Thus, a second air chamber 34 is created between the back skin 12, the front skin 10 and the spar 14.

(10) For attaching the spar 14 it comprises a lower flange 36, as well as an upper flange 38. In the first portion 28, the back skin 12 comprises an attachment flange 40, with which it is attached to the spar 14. In FIG. 1 it is clearly apparent that between the fixed leading edge 2, the spar 14 and the back skin 12 an open region 42 is present. As an upper delimitation of the open region 42, the back skin 12 comprises an outlet portion 44, which is further depicted in FIG. 2.

(11) FIG. 2 shows the spar 14 and the back skin 12 from another viewing direction. Here, it is clearly apparent that the back skin 12 is bent away from the spar 14 through a kink 46, wherein the outlet portion 44 is directly adjacent. The outlet portion 44 comprises a number of air outlets 48, through which air from the second chamber 34 can be exhausted. The outlet portion 44 is arranged in such a way that air exiting the second air chamber 34 flows in a direction that directly faces the bottom section 20. In the exemplary embodiment of FIG. 1, the outlet portion 44 is substantially flat, which allows to precisely determine the direction of flow of the air outlets 48.

(12) In addition, the back skin 12 is bent towards the front skin 10 at a region 50 directly adjacent to the outlet portion 44 opposite to the spar 14. In this example, this is conducted by a further kink 52, such that the outlet portion 44 is enclosed by two substantially parallel kinks 46 and 52.

(13) FIG. 3 shows a further illustration of the leading-edge slat 6 from a still further viewing direction. Here, a sealing device 54 is shown, which is arranged adjacent to the outlet portion 44 at a side opposite to the spar 14. The sealing device 54 allows to seal the space enclosed by the outlet portion 44, the spar 14 and the fixed leading edge 2, such that air that is exhausted from the second chamber 34 enters the open region 42 and exits into the surroundings of the aircraft afterwards.

(14) It is further apparent that the front skin 10 and the back skin 12 may be connected to a trailing edge device 56, which may be made from another material or by using a different manufacturing process. Hence, neither the front skin 10 nor the back skin 12 necessarily need to extend to an outer trailing edge 58 of the leading-edge slat 6.

(15) In FIG. 4 the flow direction of exhaust air 60 is shown from a lateral viewing direction. It is clearly apparent that the exhaust air 60 does not directly impinge the fixed leading edge 2. As a maximum, the exhaust air 60 flows tangentially along or just in front of the fixed leading edge 2. Each of the air outlets 48 is designed to comprise a through-flow direction axis 61. The spar 14 and the through-flow direction axis 61 enclose an angle α of approximately 15°. It may be advantageous to limit this angle α to 45° at a maximum in various designs, while in the exemplary embodiment it may be feasible to limit this angle to 20°, given the design of the fixed leading edge 2, the spar 14 and the outlet portion 44.

(16) In this illustration it is also apparent that the outlet portion 44 is bent away from the spar 14 through a curved transition section 59. Exemplarily, the transition section 59 has a constant radius of curvature, such that the shape and orientation of the attachment flange 40 in the first portion 28 is harmonically changing to the outlet portion 44. Stress or load peaks are thereby avoided. As an example, a similar transition section 63 is arranged at the opposed side of the outlet portion 44. A curved transition is a preferably option, if fiber-reinforced materials are used.

(17) Finally, FIG. 5 shows an aircraft 62, having a fuselage 64, wings 66 and turbofan engines 68, wherein the wings 66 are equipped with the leading-edge slats 6 explained above. The air inlets 16 of the leading-edge slats 6 may be supplied with bleed air taken from the turbofan engines 68.

(18) In addition, it should be pointed out that “comprising” does not exclude other elements or steps, and “a” or “an” does not exclude a plural number. Furthermore, it should be pointed out that characteristics or steps which have been described with reference to one of the above exemplary embodiments may also be used in combination with other characteristics or steps of other exemplary embodiments described above. Reference characters in the claims are not to be interpreted as limitations.

(19) 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.

REFERENCE NUMERALS

(20) 2 fixed leading edge

(21) 4 wing

(22) 6 leading-edge slat

(23) 8 slat body

(24) 10 front skin

(25) 12 back skin

(26) 14 spar

(27) 16 air inlet

(28) 18 leading edge

(29) 20 bottom section

(30) 22 top section

(31) 24 first air chamber

(32) 26 tube

(33) 28 first portion

(34) 30 central portion

(35) 31 second portion

(36) 32 upper end

(37) 34 second air chamber

(38) 36 lower flange

(39) 38 upper flange

(40) 40 attachment flange

(41) 42 open region

(42) 44 outlet portion

(43) 46 kink

(44) 48 air outlet

(45) 50 region

(46) 52 kink

(47) 54 sealing device

(48) 56 trailing edge device

(49) 58 trailing edge

(50) 59 transition section

(51) 60 exhaust air

(52) 61 through-flow direction axis

(53) 62 aircraft

(54) 63 transition section

(55) 64 fuselage

(56) 66 wing

(57) 68 turbofan engine

(58) α angle between spar and through-flow direction axis