Leading edge slat

Abstract

The present invention provides an aircraft wing (102, Figure 2), which includes a leading edge slat (110') and a fixed airfoil part (104). The leading edge slat (110') is capable of moving between a stowed position and a deployed position. In the deployed position, the trailing edge of the leading edge slat includes a sealed portion (112) and an unsealed portion (114). The sealed portion (112) forms a seal with the fixed airfoil part, and the unsealed portion provides an air flow gap between the leading edge flap and the fixed airfoil part. The present invention provides substantially the same benefits as a sealed leading edge slat while improving the stall control characteristics in the local area around the unsealed portion.

Description

Technical Field

[0001] The present invention relates to a leading edge slat for an aircraft wing. The present invention also relates to an aircraft wing having a leading edge slat, and an aircraft including an aircraft wing having a leading edge slat. The leading edge slat can be configured to reduce drag at some locations on the aircraft wing, and to assist in controlling the stall characteristics at other locations. Background Art

[0002] A leading edge slot is provided on an aircraft wing to increase the lift provided by the aircraft wing during takeoff and / or landing. The leading edge slat is typically provided with a retracted position and a deployed position, and during normal flight operations, the leading edge slat is in the retracted position, and the leading edge slat moves to the deployed position for takeoff and / or landing.

[0003] It is known that the leading edge slat is provided with a seal such that in the deployed position, the leading edge slat seals against the main airfoil structure of the wing. Such an arrangement is shown in US8899528B2. Providing a sealed leading edge slat can reduce the drag generated by the leading edge slat when in the deployed position, which can also reduce the noise generated during takeoff and / or landing, and also has fuel efficiency benefits. However, there are also benefits to an unsealed leading edge slat, which can provide better stall control benefits than a sealed leading edge slat. Currently, choosing between a sealed leading edge slat and an unsealed leading edge slat represents a compromise.

[0004] The present invention seeks to alleviate one or more of the above problems. Summary of the Invention

[0005] According to a first aspect, the present invention provides an aircraft wing including a leading edge slat and a fixed airfoil portion, the leading edge slat being movable between a retracted position and a deployed position, wherein in the deployed position, the trailing edge of the leading edge slat includes a sealed portion and an unsealed portion, the sealed portion forming a seal with the fixed airfoil portion, and the unsealed portion providing an air flow gap between the leading edge flap and the fixed airfoil portion.

[0006] The sealed portion may extend across at least 75%, 80%, 85%, 90%, or 95% of the trailing edge of the leading edge slat. The direction in which the sealed portion extends may be in the spanwise direction of the leading edge slat.

[0007] The leading edge slat may include an inner end and an outer end, the inner end being positioned towards the root of the aircraft wing, and the outer end being positioned towards the tip of the aircraft wing. The unsealed portion may be located at the inner end or the outer end of the leading edge slat.

[0008] An aircraft wing may include a seal positioned to provide a sealed portion for a leading edge slat. The seal may be located on one or both of the leading edge slat and the fixed airfoil portion. In an alternative arrangement, the sealed portion may simply include a portion of the leading edge slat and a portion of the fixed airfoil portion that remain in contact such that the sealed portion is provided.

[0009] The unsealed portion may include a trailing edge of the leading edge slat that can be manipulated to form an air flow gap. For example, the trailing edge of the leading edge slat may be stepped to form an air flow gap. Alternatively or additionally, the profile of the fixed airfoil portion may be manipulated to form an air flow gap. For example, the profile of the fixed airfoil portion may be stepped or reduced in order to form an air flow gap.

[0010] The leading edge slat may be fully sealed against the fixed airfoil portion when in the stowed position. Full sealing means that the leading edge slat is sealed along 100% of the span of the leading edge slat. An aircraft wing may include a seal configured to seal the leading edge slat in the stowed position.

[0011] The unsealed portion may be configured to manipulate the air flow between the trailing edge of the leading edge slat and an associated portion of the fixed airfoil structure. For example, the unsealed portion may include one or more vortex generators.

[0012] The unsealed portion may be positioned adjacent to or near a portion of the aircraft wing that disrupts the air flow. For example, such a component may be a wing tip device or a wing-mounted engine. The inventors have recognized that at wing locations such as at wing tip devices or engine installations, the benefits of a sealed leading edge slat may be reduced or eliminated. These locations may also be potential stall points of the air flow. It has been found that positioning the unsealed portion at a location adjacent to or near these locations improves the stall characteristics at a location near the local aircraft wing structure.

[0013] The deployed position may be the takeoff position. There may be another position where the leading edge slat is deployed such that no seal is formed between the leading edge slat and the fixed airfoil portion. Such a position may be the landing position. The stowed position may be the "normal flight" position. For example, during cruise flight of the aircraft, the leading edge slat may be stowed.

[0014] According to a second aspect, the present invention provides an aircraft including an aircraft wing according to the first aspect of the present invention.

[0015] According to a third aspect, the present invention provides a leading edge slat for an aircraft wing according to the first aspect of the present invention.

[0016] The aircraft can be a passenger aircraft. The passenger aircraft can include a passenger cabin, and the passenger cabin includes multiple rows and columns of seat units for accommodating a large number of passengers. The aircraft can have a capacity of at least 20 passengers, at least 50 passengers, or more than 50 passengers. The aircraft can be a powered aircraft. The aircraft can include an engine for propelling the aircraft. The aircraft can include wing-mounted engines, such as under-wing engines.

[0017] Of course, it will be understood that features described in connection with one aspect of the present invention can be incorporated into other aspects of the present invention. For example, the methods of the present invention can incorporate any features described with reference to the apparatus of the present invention, and vice versa.

[0018] Unless the context otherwise requires, the term "or" shall be construed as "and / or". BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Embodiments of the present invention will now be described by way of example only with reference to the accompanying schematic drawings, in which:

[0020] Figure 1 An aircraft having an aircraft wing including a first embodiment of the present invention is shown;

[0021] Figure 2 As shown Figure 1 A plan view of a portion of the aircraft wing as shown therein;

[0022] Figure 3 Shown Figure 2 A schematic view of the aircraft wing as shown therein;

[0023] Figure 4 A variant of the first embodiment of the present invention is shown;

[0024] Figure 5 A cross-sectional view of a sealed portion of a wing according to the first embodiment of the present invention is shown;

[0025] Figure 6 A cross-sectional view of an unsealed portion of a wing according to the first embodiment of the present invention is shown;

[0026] Figure 7 A cross-sectional view of an unsealed portion of a wing according to the second embodiment of the present invention is shown;

[0027] Figure 8 A plan view of the first embodiment of the present invention is shown, and Figure 9 Shown along Figure 8 A cross-sectional view taken along different axes as shown therein;

[0028] Figure 10Shows a plan view of a third embodiment of the present invention, and Figure 11 shows a cross-sectional view taken along Figure 10 the different axes shown in Detailed Description

[0029] Figure 1 Shows an aircraft 100. The aircraft 100 includes a first aircraft wing and a second aircraft wing 102. Since the aircraft wings 102 are mirror images of each other, only the elements associated with a single wing 102 will be described. Those skilled in the art will understand that the elements described with respect to one wing are present as mirror images on the other wing 102. The wing 102 includes a body 104 and a wingtip device 106. The body 104 is the conventional fixed airfoil portion of the aircraft wing 102. The wingtip device 106 may be movable to reduce the wingspan of the aircraft 100, or the wingtip device 106 may be fixed. Two under-wing engines 108 are mounted to the wing 102. A plurality of leading-edge slats 110 are provided at the leading edge of the wing 102. As is conventional and readily understood by those skilled in the art, the leading-edge slats 110 have a deployed position in which the leading-edge slats 110 move forward and tend to move downward relative to the overall wing 102 such that, compared to when the leading-edge slats 110 are in a stowed position flush with the overall wing 102, the leading-edge slats 110 form a wing 102 with a higher lift. When the aircraft 100 takes off or lands, the leading-edge slats 110 move to the deployed position to allow a sharper angle of attack for these maneuvers. Once the aircraft 100 has taken off and is no longer climbing steeply, or has entered a level flight state, the leading-edge slats 110 move to the stowed position to reduce drag compared to the deployed position, thereby allowing for more efficient flight. The leading-edge slats 110 may remain in the stowed position during the initial stages of descent and only move to the deployed position when the descent angle increases to a certain value or the speed of the aircraft is sufficiently reduced. As will be understood by those skilled in the art, various different actuators and actuation methods may be used to move the leading-edge slats 110 between the deployed position and the stowed position. Accordingly, no further description of the actuators or actuation methods will be provided.

[0030] As can be seen, the leading-edge slats 110 extend across most of the leading edge of the wing. This results in multiple portions of the leading-edge slats 110 being located at positions close to potential stall points where the airflow may be disrupted and move over the wing. Such points include positions close to the under-wing engines 108 and the position where the wingtip device 106 is connected to the body 104. Figure 2 Shows a section of the leading-edge slat 110' at the distal end of the wing 102, at the point where the wingtip device 106 is connected to the body 104. In Figure 2 this, the leading-edge slat 110' is in the stowed position. Figure 3A perspective view of a leading edge slat 110' in the deployed position is shown. The leading edge slat 110' is divided into two parts, a sealed part 112 and an unsealed part 114. When the leading edge slat 110' is in the deployed position, the sealed part 112 seals against the body 104. The sealed leading edge slat can provide advantages such as reduced drag, lower fuel consumption, and / or reduced noise compared to an unsealed leading edge slat. When the leading edge slat 110' is in the deployed position, the unsealed part does not seal against the body 104 and provides an air flow gap 116 between the leading edge slat 110' and the body 104. The air flow gap 116 can cause the air flow passing through the gap to accelerate, which results in an improvement in the air flow in the vicinity of the air flow gap. However, since the air flow gap only exists in a specified part of the leading edge slat 110', the benefits of providing a sealed leading edge slat are generally maintained. In Figure 2 In the embodiment shown, it can be seen that the unsealed part 114 is formed by reducing the chord length of the leading edge slat 110' such that in the deployed position, the trailing edge of the leading edge slat 110' does not contact the body 104. In contrast, when in the deployed position, the trailing edge of the sealed part 112 of the leading edge slat 110' contacts the body 104. One or more sealing strips or sealing elements extending from the leading edge slat 110' or the body 104 can be provided to ensure a good seal between the sealed part 112 of the leading edge slat 110' and the body 104. Alternatively, the seal can be provided by a direct contact portion between the leading edge slat 110' and the body 104.

[0031] To maintain the benefits of the sealed leading edge slat, the unsealed part 114 forms a small part of the leading edge slat 110'. For example, the unsealed part can include approximately 10% of the wingspan of the leading edge part 110', with the remaining 90% being composed of the sealed part 112. Those skilled in the art will recognize that the benefits of the present invention can still be obtained when the unsealed part 114 constitutes 5% to 25% of the wingspan of the leading edge part 110' such that the sealed part 112 constitutes the remainder.

[0032] The leading edge slat 110' is shaped such that when in the stowed position, the entire trailing edge of the slat seals against the body 104. This may also require the body 104 to be appropriately shaped, or different sealing strips or sealing elements to be provided to allow the above solution.

[0033] Figure 4 An alternative embodiment is shown, which is substantially similar to the embodiment described with reference to Figures 1 to 3 If similar elements are provided, the same reference numerals are used. Figure 4The difference shown in [Figure] is that the unsealed portion 114 of the leading-edge slat 310 further includes three vortex generators 118. The vortex generators can further improve the airflow at the point where the main body 104 meets the wingtip device 106.

[0034] Figure 5 A cross-sectional view taken perpendicular to the leading edge of the leading-edge slat of the wing according to the first embodiment of the present invention is shown. The starting view shows the stowed position and how the leading-edge slat 110' is positioned relative to the main body 104. The second view shows the leading-edge slat 110' in the deployed takeoff position. The trailing edge of the leading-edge slat 110' remains in contact with the main body 104. The third view shows the leading-edge slat 110' in the deployed landing position. In this case, the trailing edge of the leading-edge slat does not contact the fixed airfoil portion, and the leading-edge slat 110' has extended beyond the deployed takeoff position.

[0035] Figure 6 A cross-sectional view taken perpendicular to the leading edge of the leading-edge slat of the non-sealed portion of the wing according to the first embodiment of the present invention is shown. The starting view shows the leading-edge slat in the stowed position, where the trailing edge of the leading-edge slat 110' is in contact with the main body 104. The second view shows the leading-edge slat in the deployed takeoff position, with a clear gap between the trailing edge of the leading-edge slat 110' and the main body 104. In this case, the main body 104 has a uniform cross-section along the entire length of the leading-edge slat 110, and the leading-edge slat 110 includes a removed section to provide an unsealed portion. A uniform cross-section does not imply that the cross-sections are the same, as the dimensions will taper as the main body moves out along the wingspan direction, and a uniform cross-section means that any such taper is smoothly graduated. The third view shows the leading-edge slat 110 in the deployed landing position. As in Figure 5 [Figure], there is a clear gap between the trailing edge of the leading-edge slat 110' and the main body 104.

[0036] Figure 7 A cross-sectional view taken perpendicular to the leading edge of the leading-edge slat of the non-sealed portion of the wing according to the second embodiment of the present invention is shown. In this embodiment, the unsealed portion is formed by shaping the main body 104 to provide a gap between the main body and the leading-edge flap 710. The dashed line represents the cross-sectional profile of the main body 104 along the entire sealed portion of the leading-edge slat 710, and is the same as that shown with reference to Figure 5 [Figure]. It can be seen that in the takeoff position, the trailing edge of the leading-edge slat 710 remains in contact with the main body 104. As in Figure 9As can be better seen, contrary to the first embodiment, the trailing edge of the leading edge slat 710 is uniformly shaped along the entire length of the leading edge slat 710. The starting view shows the leading edge slat in the retracted position, where the trailing edge of the leading edge slat 710 contacts the main body 104. The second view shows the leading edge slat in the deployed takeoff position, where there is a clear gap between the trailing edge of the leading edge slat 710 and the main body 104. The third view shows the leading edge slat 710 in the deployed landing position. As Figure 5 shown, when in the deployed landing position, there is a clear gap between the trailing edge of the leading edge slat 710 and the main body 104.

[0037] Figure 8 and Figure 9 show a plan view of the first embodiment of the present invention and a cross-sectional view taken along the first line A-A - which shows the unsealed portion - and a cross-sectional view taken along the second line B-B - which shows the sealed portion. The leading edge portion 110’ is in the deployed position. Figure 8 The plan view in shows the leading edge slat in the deployed takeoff position, and the arrow indicates the airflow through the unsealed portion.

[0038] Figure 10 and Figure 11 show a plan view of the second embodiment of the present invention and a cross-sectional view taken along the first line A-A - which shows the unsealed portion - and a cross-sectional view taken along the second line B-B - which shows the sealed portion. The leading edge portion 710 is in the deployed position. Figure 10 The plan view in shows the leading edge slat in the deployed takeoff position, and the arrow indicates the airflow through the unsealed portion.

[0039] As will be understood by those skilled in the art, alternative arrangements may be provided. For example, the leading edge slat may be positioned such that the unsealed portion is close to an alternative portion of the wing. Such a position may be close to the bottom engine 108.

[0040] In the foregoing description, when referring to a whole or an element having known, obvious or foreseeable equivalents, such equivalents are incorporated herein as if set forth separately. The true scope of the present invention should be determined with reference to the claims, and the true scope of the present invention should be construed to include any such equivalents. The reader will also understand that the overall components or features of the present invention described as being preferred, advantageous, convenient, etc. are optional and do not limit the scope of the independent claims. Further, it should be understood that such optional wholes or features that may be beneficial in some embodiments of the present invention may be undesirable and thus may not be present in other embodiments.

Claims

1. An aircraft wing, the aircraft wing comprising a leading edge slat and a fixed airfoil portion, the leading edge slat being movable between a retracted position and a deployed position, wherein, In the deployed position, the trailing edge of the leading edge slat includes a sealed portion and an unsealed portion, the sealed portion forming a seal with the fixed airfoil portion, and the unsealed portion providing an air flow gap between the leading edge slat and the fixed airfoil portion. Wherein, the leading edge slat includes an inner end and an outer end, the inner end being positioned towards the root of the aircraft wing, and the outer end being positioned towards the tip of the aircraft wing. Wherein, the unsealed portion is located at the outer end of the leading edge slat and is close to the portion of the aircraft wing that disrupts the air flow, and The sealed portion extends at least across 75% of the spanwise length of the trailing edge of the leading edge slat, wherein the spanwise length extends from the inner end of the leading edge slat to the outer end of the leading edge slat.

2. The aircraft wing according to claim 1, comprising a seal configured to provide the sealed portion of the leading edge slat.

3. The aircraft wing according to claim 2, wherein, The seal is located on one or both of the leading edge slat and the fixed airfoil portion.

4. The aircraft wing according to claim 1, wherein, The sealed portion includes a direct contact portion located between the trailing edge of the leading edge slat and the fixed airfoil portion.

5. The aircraft wing according to claim 1, wherein, The unsealed portion includes the trailing edge of the leading edge slat shaped to form the air flow gap.

6. The aircraft wing according to claim 5, wherein, The trailing edge of the leading edge slat is stepped to form an air flow gap.

7. The aircraft wing according to claim 1, wherein, The profile of the fixed airfoil portion is shaped to form the air flow gap.

8. The aircraft wing according to any one of claims 1 to 7, wherein, The leading edge slat is completely sealed against the fixed airfoil portion when in the stowed position.

9. The aircraft wing according to any one of claims 1 to 7, comprising a seal configured to seal the leading edge slat in the stowed position.

10. The aircraft wing according to any one of claims 1 to 7, wherein, The unsealed portion is configured to manipulate the air flow between the trailing edge of the leading edge slat and the associated portion of the fixed airfoil structure.

11. The aircraft wing according to claim 10, wherein, The unsealed portion includes a vortex generator.

12. An aircraft, the aircraft comprising the aircraft wing according to any one of claims 1 to 11.

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