Wing tip device

1. A wing tip device, or a wing having a wing tip device, for a fixed wing aircraft, comprising:

a first leading edge region having a first sweep angle,

a second leading edge region outboard of the first leading edge region in a spanwise direction and having a second sweep angle smaller than the first sweep angle, wherein the first leading edge region is blended into the second lead edge region by a concave junction,

a third leading edge region outboard of the second leading edge region in the spanwise direction and adjacent a tip end of the wing tip device, and having a third sweep angle greater than the first sweep angle,

wherein the second leading edge region is adapted to generate a first vortex, and

wherein the third leading edge region is adapted to generate a second vortex which builds towards the tip end of the wing tip device,

wherein a trailing edge of the wing tip device includes a convex portion, and

wherein the third leading edge connects a portion of the concave junction with the convex portion by a tip end and the second leading edge region of the wing tip device.

2. A wing tip device or a wing according to claim 1 , wherein the first, second and third leading edge regions are located along a single line when the wing tip device is viewed in the aircraft longitudinal direction.

3. A wing tip device or a wing according to claim 1 , wherein the first leading edge region and the second leading edge region are opposing.

4. A wing tip device or a wing according to claim 1 , wherein the first leading edge region is substantially straight.

5. A wing tip device or a wing according to claim 1 , wherein the first sweep angle is at least 20 degrees.

6. A wing tip device or a wing according to claim 1 , wherein the second and third sweep angles are each at least 35 degrees.

7. A wing tip device or a wing according to claim 1 , wherein the second leading edge region is forward swept.

8. A wing tip device or a wing according to claim 1 , wherein the third leading edge region is aft swept.

9. A wing tip device or a wing according to claim 1 , wherein a chord length of the wing tip device in the second leading edge region increases in the outboard spanwise direction.

10. A wing tip device or a wing according to claim 1 , wherein a chord length of the wing tip device in the third leading edge region decreases in the outboard spanwise direction.

11. A wing tip device or a wing according to claim 1 , wherein a trailing edge of the wing tip device includes a convex portion.

12. A wing tip device or a wing according to claim 11 , wherein the convex portion is at substantially the same spanwise location as the second and/or third leading edge regions.

13. A wing tip device or a wing according to claim 1 , wherein the second leading edge region is inboard of the tip end of the wing tip device in the spanwise direction.

14. A wing tip device or a wing according to claim 1 , wherein the second leading edge region is blended into the first leading edge region.

15. A wing tip device or a wing according to claim 1 , wherein the second leading edge region extends up to the third leading edge region.

16. A wing tip device or a wing according to claim 15 , wherein the second leading edge region and the third leading edge region meet to form a sharp leading edge cusp.

17. A wing tip device or a wing according to claim 15 , wherein the second leading edge region and the third leading edge region meet to form a smooth leading edge crest.

18. A wing tip device or a wing according to claim 1 , wherein the second leading edge region and the third leading edge region are separated by a notched leading edge region.

19. A wing tip device or a wing according to claim 1 , wherein a lower aerodynamic surface of the wing tip device and/or wing includes a concave portion adjacent the leading edge.

20. A wing tip device or a wing according to claim 19 , wherein the concave portion of the lower aerodynamic surface is provided in an aerofoil section that includes the second leading edge region or the third leading edge region.

21. A wing tip device or a wing according to claim 1 , wherein the second leading edge region and/or the third leading edge region is moveable between a retracted and a deployed state.

22. A wing tip device or a wing according to claim 1 , wherein the second and/or third leading edge regions are fixed.

23. A wing tip device or a wing according to claim 1 , wherein the wing tip device further comprises a downlet.

24. A wing tip device, or a wing according to claim 1 , wherein the wing tip device or wing comprises an alular-like projection.

25. A wing according to claim 1 , wherein the wing has a root end, a tip end, and a leading edge high lift device extending outboard in the spanwise direction up to adjacent the tip end of the wing.

26. A wing according to claim 1 , wherein the wing has a root end and a tip end, the wing tip device is coupled to the tip end of the wing, and the wing has a hinge intermediate the root end and the tip end for folding the tip end of the wing.