An aircraft wing comprises a leading-edge slat, the slat including a main body portion and a slat extension arranged at a spanwise end of the main body portion. The cross-sectional area of the slat extension is less than the cross-sectional area of the main body portion. The slat extension may therefore provide some of the aerodynamic benefits of the slat, while enabling the volume of the leading-edge of the wing on which the slat is mounted, to be relatively large. The chord and thickness to chord ratio of the slat extension may be less than the equivalent dimensions on the slat.
1. An aircraft wing comprising a leading-edge slat, the slat including:
(i) a main body portion the front of which forms an aerodynamic surface exposed to free-stream airflow and the rear of which is shaped to complement the part of the wing behind the slat main body portion, and
(ii) a slat extension arranged at a spanwise end of the main body portion and projecting therefrom, the front of which slat extension forms an aerodynamic surface exposed to the free-stream airflow and the rear of which slat extension is shaped to complement the part of the wing behind the slat extension,
wherein the slat extension is fixed relative to the main body portion;
wherein the leading-edge profile of the aerodynamic surface of the slat extension is contiguous with at least part of the leading edge profile of the aerodynamic surface of the main body portion, and
wherein the rear of the slat extension is positioned forward of the rear of the slat main body portion such that the cross-sectional area of the slat extension, in a first vertical plane containing the aircraft wing chord, is less than the cross-sectional area of the main body portion, in a second vertical plane containing the aircraft wing chord.
2. An aircraft wing according to claim 1 wherein the cross-sectional area of the slat extension is less than 60% of the cross-sectional area of the main body portion.
3. An aircraft wing according to claim 2 wherein the cross-sectional area of the slat extension is less than 40% of the cross-sectional area of the main body portion.
4. An aircraft wing according to claim 1 wherein the cross-sectional area of the slat extension is more than 5% of the cross-sectional area of the main body portion.
5. An aircraft wing according to claim 1 , the slat extension having substantially constant cross-sectional area along substantially its entire length.
6. An aircraft wing according to claim 1 wherein the slat extension and the main body portion meet at a junction, the cross-sectional area of the slat varying sharply across the junction.
7. An aircraft wing according to claim 1 wherein the average chord of the slat extension is less than the average chord of the main body portion.
8. An aircraft wing according to claim 7 wherein the average chord of the slat extension is less than 60% of the average chord of the main body portion.
9. An aircraft wing according to claim 8 wherein the average chord of the slat extension is less than 40% of the average chord of the main body portion.
10. An aircraft wing according to claim 1 wherein the average thickness of the slat extension is less than the average thickness of the main body portion.
11. An aircraft wing according to claim 10 wherein the average thickness-to-chord ratio of the slat extension is between 80% and 150% of the average thickness-to-chord ratio of the main body portion.
12. An aircraft wing according to claim 1 , the wing further comprising an engine pylon, the slat extension being arranged at the spanwise end of the main body portion closest to the engine pylon.
13. A leading-edge slat for use on the aircraft wing according to claim 1 .
14. An aircraft wing, at least part of the fore region of the wing being shaped so as to receive, and be complementary with, a leading-edge slat according to claim 13 .
15. An aircraft wing according to claim 14 , wherein said part of the fore region of the wing includes first and second regions which are shaped such that, when the leading-edge slat is installed on the wing, the first region is complementary with the main body portion of the slat, and the second region is complementary with the slat extension, the second region protruding beyond the first region.
16. An aircraft comprising an aircraft wing according to claim 1 .