LEADING EDGE STRUCTURE FOR A FLOW CONTROL SYSTEM OF AN AIRCRAFT

Abstract

A leading edge structure (11) for a flow control system of an aircraft (1) including a leading edge panel (13) surrounding a plenum (17) that extends in a span direction (19). The leading edge panel (13) has a first side portion (21) extending from a leading edge point (23) to a first attachment end (25) and a second side portion (27) opposite the first side portion (21), extending from the leading edge point (23) to a second attachment end (29), wherein the leading edge panel (13) comprises an inner surface (33) facing the plenum (17) and an outer surface (37) in contact with an ambient flow (39), and wherein the leading edge panel (13) comprises a plurality of micro pores (45) forming a fluid connection between the plenum (17) and the ambient flow (39).

Claims

1. A leading edge structure for a flow control system of an aircraft, the leading edge structure comprising a leading edge panel that surrounds a plenum in a curved manner, the plenum extending in a span direction, wherein the leading edge panel has a first side portion extending from a leading edge point to a first attachment end, wherein the leading edge panel has a second side portion opposite the first side portion, extending from the leading edge point to a second attachment end, wherein the leading edge panel comprises an inner surface facing the plenum and an outer surface in contact with an ambient flow, and wherein the leading edge panel comprises a plurality of micro pores forming a fluid connection between the plenum and the ambient flow, wherein the plenum is separated by a partition wall into a leading edge plenum section in an area adjacent the leading edge point, and a downstream plenum section downstream from the leading edge plenum section, the leading edge plenum section is connected to a first air outlet via a first duct, the downstream plenum section is connected to a second air outlet via a second duct, and the first air outlet is separate from the second air outlet and the first duct is separate from the second duct.

2. The leading edge structure according to claim 1, wherein the first air outlet comprises a pivotal first door that opens in a rearward direction, wherein the first door is configured to be set to an opened position for letting out a predefined mass flow rate of air adapted for flow control in the area of the leading edge.

3. The leading edge structure according to claim 1, wherein the first air outlet comprises a pivotal first door that opens in a rearward direction, wherein the first door is configured to be set to a first opened position for letting out a predefined first mass flow rate of air adapted for flow control in the area of the leading edge, and to a second opened position for letting out a predefined second mass flow rate of air adapted for cleaning the micro pores in the area of the leading edge.

4. The leading edge structure according to claim 3, wherein the second mass flow rate is between 200% and 400% greater than the first mass flow rate.

5. The leading edge structure according to claim 1, wherein the second air outlet comprises a pivotal second door that opens in a rearward direction, wherein the second door is configured to be set to a first opened position for letting out a predefined third mass flow rate of air adapted for flow control in the area downstream from the leading edge area, and to a second opened position for letting out a predefined fourth mass flow rate of air adapted for cleaning the micro pores in the area downstream from the leading edge area.

6. The leading edge structure according to claim 5, wherein the fourth mass flow rate is between 200% and 400% greater than the third mass flow rate.

7. The leading edge structure according to claim 1, wherein the second air outlet is formed as a combined air inlet/outlet device configured for both letting in air from the ambient flow and discharging air into the ambient flow.

8. The leading edge structure according to claim 7, wherein the air inlet/outlet device comprises a pivoting inlet door opening in a forward direction to let in air from the ambient flow, and an outlet door opening in a rearward direction to discharge air into the ambient flow, wherein the inlet door is configured to be set to an opened position for letting in a predefined mass flow rate of air adapted for cleaning the micro pores in the area downstream from the leading edge area, and wherein the outlet door is configured to be set to an opened position for letting out a predefined mass flow rate of air adapted for flow control in the area downstream from the leading edge area.

9. The leading edge structure according to claim 8, wherein the inlet door and the outlet door are formed integrally or are mounted to one another.

10. A vertical tail plane for an aircraft comprising a vertical tail plane box having a first lateral panel with a first attachment portion and an opposite second lateral panel with a second attachment portion; a leading edge structure including: a curved leading edge panel at least partially surrounding a plenum extending in a span direction; wherein the leading edge panel has a first side portion extending from a leading edge point to a first attachment end; wherein the leading edge panel has a second side portion opposite the first side portion, extending from the leading edge point to a second attachment end; wherein the leading edge panel comprises an inner surface facing the plenum and an outer surface in contact with an ambient flow; wherein the leading edge panel comprises a plurality of micro pores forming a fluid connection between the plenum and the ambient flow; wherein the plenum is separated by a partition wall into a leading edge plenum section in an area adjacent the leading edge point, and a downstream plenum section downstream from the leading edge plenum section; wherein the leading edge plenum section is connected to a first air outlet via a first duct, wherein the downstream plenum section is connected to a second air outlet via a second duct, and the first air outlet is separate from the second air outlet and the first duct is separate from the second duct, wherein the first attachment end is attached to the first attachment portion, and wherein the second attachment end is attached to the second attachment portion, so that the first side portion of the leading edge panel forms a continuous flow surface with the first lateral panel of the vertical tail plane box, and the second side portion of the leading edge panel forms a continuous flow surface with the second lateral panel of the vertical tail plane box.

11. The vertical tail plane according to claim 10, wherein the first air outlet and/or the second air outlet is arranged in the first lateral panel and/or in the second lateral panel and/or in another leading edge panel arranged beside the leading edge structure in the span direction.

12. An aircraft comprising the leading edge structure according to claim 10.

13. The aircraft according to claim 12, further comprising a control unit configured to control the aircraft to operate in a flow control mode by setting the first door to the opened position, the inlet door to the closed position, and the outlet door to the opened position, and in a cleaning mode by setting the first door to the opened position, the inlet door to the opened position, and the outlet door to the closed position.

14. A vertical tail plane for an aircraft comprising a vertical tail plane box having a first lateral panel including a first attachment portion and a second lateral panel with a second attachment portion, wherein the second lateral panel is opposite to the first later panel; a leading edge structure attached to the vertical tail plane box, the leading edge structure including a first leading edge panel extending from a leading edge of the vertical tail plane to the first attachment portion, and a second leading edge panel extending from the leading edge to the second attachment portion, wherein the second leading edge panel is opposite the first leading edge panel; a plenum defined, at least partially, by inner surfaces of the first and second leading edge panels, wherein the plenum includes a leading edge plenum section adjacent the leading edge, a partition wall aft of the leading edge and extending between the first and second leading edge panels, and a downstream plenum section aft of the partition wall; micro pores in the first and second leading edge panels, the micro pores configured for fluid communication between ambient air flowing over the leading edge structure and air within the leading edge plenum section and the downstream plenum section; a first air outlet in fluid communication with the leading edge plenum via a first duct; and a second air outlet in fluid communication with the downstream plenum via a second duct, wherein the second air outlet and the second duct are from the first air outlet and the first duct.

15. The vertical tail plane of claim 14, wherein the first air outlet includes a first door on an outer surface of the vertical tail plane and configured to open to form an opening into the first duct downstream of the first door.

16. The vertical tail plane of claim 15, wherein the first door is configured to open to a first opened position and a second open position, wherein an air mass flow rate through the first duct is 200% and 400% greater while the first door is in the second position as compared to a mass flow rate through the first duct while the first door is in the first position.

17. The vertical tail plane of claim 14, wherein the second air outlet includes a second door configured to form an opening to the second duct, wherein the second door is configured to be opened to a first position in which the second door deflects ambient air into the second duct and to a second position in which the second door deflects ambient air away from the second duct.

18. The vertical tail plane of claim 17, wherein the second door is for both directing ambient air into the second duct and for discharging air from the plenum into the ambient flow.

19. The vertical tail plane of claim 17, wherein the second door configured to, while in the first position, open in a forward direction to face the ambient air and thereby direct ambient air into the second duct, and, while in the second position, open in a rearward direction such that the opening to the second duct is downstream of the second door.

20. The vertical tail plane of claim 19, wherein second door includes an inlet door to be opened in the first position and the outlet door to be opened in the second position.

Description

SUMMARY OF THE DRAWINGS

[0027] An embodiment(s) of the present invention is described hereinafter in more detail by means of a drawing. The drawing shows in

[0028] FIG. 1 a perspective view of an aircraft according to the invention,

[0029] FIG. 2 a side view of a vertical tail plane according to the invention, and

[0030] FIG. 3 a cross sectional view across the span direction of a leading edge structure according to the invention.

DETAILED DESCRIPTION OF AN EMBODIMENT(S) OF THE INVENTION

[0031] In FIG. 1 an aircraft 1 according to an embodiment of the present invention is shown. The aircraft comprises a fuselage 3, wings 5, a horizontal tail plane 7, and a vertical tail plane 9 according to an embodiment of the invention. The vertical tail plane 9 is shown in more detail in FIG. 2. The vertical tail plane 9 comprises a leading edge structure 11 according to an embodiment of the invention. The leading edge structure 11 is shown in more detail in FIG. 3.

[0032] The leading edge structure 11 is configured for a hybrid laminar flow control system and comprises a leading edge panel 13 and a back wall 15. The leading edge panel 13 surrounds a plenum 17 in a curved manner. The plenum 17 extends in a span direction 19 through the leading edge structure 11. When viewed in a cross section across the span direction 19, the leading edge panel 13 has a first side portion 21 extending from a leading edge point 23 to a first attachment end 25 on a first side of the leading edge structure 11. Further, the leading edge panel 13 has a second side portion 27 opposite the first side portion 21, wherein the second side portion 27 extends from the leading edge point 23 to a second attachment end 29 on a second side of the leading edge structure 11 opposite the first side. The back wall 15 connects the first attachment end 25 to the second attachment end 29 of the leading edge panel 13, thereby enclosing the plenum 17 on a side opposite the leading edge point 23.

[0033] The leading edge panel 13 has a double-walled form including an inner wall element 31 having an inner surface 33 facing the plenum 17, and an outer wall element 35 having an outer surface 37 in contact with an ambient flow 39. Between the inner and outer wall elements 31, 35 the leading edge panel 13 comprises a plurality of elongate stiffeners 41 extending in the span direction 19 and spaced apart from one another, so that between each pair of adjacent stiffeners 41 a hollow chamber 43 is formed between the inner and outer wall elements 31, 35. The stiffeners 41 are formed integrally with the inner wall element 31 in a sandwich form and have a solid, trapezoid-shaped cross section. The inner wall element 31 is formed of a fiber reinforced plastic (FRP). The outer wall element 35 is formed as a titanium sheet and comprises a plurality of micro pores 45 forming a fluid connection between the hollow chambers 43 and the ambient flow 39. The inner wall element 31 comprises openings 47 forming a fluid connection between the hollow chambers 43 and the plenum 17.

[0034] As shown in FIG. 3, the plenum 17 is separated by a partition wall 49 into a leading edge plenum section 51 in the area of the leading edge point 23, and a downstream plenum section 53 downstream from the leading edge plenum section 51. The partition wall 49 extends in parallel to the span direction 19 and is formed as a membrane of fiber reinforced plastic. Both plenum sections 51, 53 are sealed from one another, so that the pressure in the leading edge plenum section 51 does not affect the pressure in the downstream plenum section 53. The leading edge plenum section 51 is connected to a first air outlet 55 via a first duct 57 for discharging air to the ambient flow 39. Further, the downstream plenum section 53 is connected to a second air outlet 59 via a second duct 61 for discharging air to the ambient flow 39. The first air outlet 55 is separate from the second air outlet 59 and the first duct 57 is separate from the second duct 61.

[0035] The first air outlet 55 comprises a pivotal first door 62 that opens in a rearward direction and that is configured to be set to a closed position, where no mass flow of air can pass to the ambient flow 39, and to an opened position corresponding to a predefined opening angle for letting out a predefined mass flow rate of air from the leading edge plenum section 51 adapted for flow control.

[0036] The second air outlet 59 is formed as combined air inlet/outlet devices 63 configured for both letting in air from the ambient flow 39 and discharging air into the ambient flow 39. The air inlet/outlet device 63 comprises a pivotal inlet door 64 opening in a forward direction to let in air from the ambient flow 39 and pass it to the downstream plenum section 53 and finally blow it out through the micro pores 45. The air inlet/outlet device 63 further comprises a pivotal outlet door 66 opening in a rearward direction to discharge air from the downstream plenum section 53 into the ambient flow 39. The inlet door 64 is configured to be set to a closed position where any mass flow of air from the ambient flow 39 to the second duct 61 is inhibited, and to an opened position corresponding to a predefined opening angle for letting in a predefined mass flow rate of air adapted for cleaning the micro pores 45 in the area downstream from the leading edge area from liquid and other contaminants during take-off and landing approach of the associated aircraft 1. Likewise, the outlet door 66 is configured to be set to a closed position where any mass flow of air from the second duct 61 to the ambient flow 39 is inhibited, and to an opened position corresponding to a predefined opening angle for letting out a predefined mass flow rate of air adapted for flow control in the area downstream from the leading edge area. The inlet door 64 and the outlet door 66 are formed integrally as one common door that is pivotable inwards to the inside of the vertical tail plane 9 as well as outwards into the ambient flow 39.

[0037] As shown in FIGS. 2 and 3, the vertical tail plane 9 comprises a vertical tail plane box 65 and the leading edge structure 11 is mounted to the vertical tail plane box 65. The vertical tail plane box 65 has a first lateral panel 67 with a first attachment portion 69 and an opposite second lateral panel 71 with a second attachment portion 73. The first attachment end 25 of the leading edge structure 11 is attached to the first attachment portion 69 and the second attachment end 29 is attached to the second attachment portion 73, so that the first side portion 21 of the leading edge panel 13 forms a continuous flow surface with the first lateral panel 67 of the vertical tail plane box 65 and the second side portion 27 of the leading edge panel 13 forms a continuous flow surface with the second lateral panel 71 of the vertical tail plane box 65. The first air inlet 55 and the second air inlet 59 are arranged on opposite sides in another leading edge panel 75 beside the leading edge structure 11 with respect to the span direction 19. The first and second ducts 57, 61 extend through the space between the vertical tail plane box 65 and the other leading edge panel 75.

[0038] The aircraft further comprises a control unit 77 configured to control the aircraft 1 to operate in a flow control mode by setting the first door 62 to the opened position, the inlet door 64 to the closed position, and the outlet door 66 to the opened position, and in a cleaning mode by setting the first door 62 to the opened position, the inlet door 64 to the opened position, and the outlet door 66 to the closed position.

[0039] 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.