Winglet
A winglet comprising a root connected to a distal end of a wing; an upwardly angled section; a tip; and a transition between the upwardly angled section and the tip at which an outboard cant angle of the winglet decreases relative to a reference plane of the wing. In one embodiment the winglet is continuously curved and includes a point of inflection at which the span-wise curvature of the winglet changes sign. In another embodiment the upwardly angled section is planar. The winglet generates a tip vortex when in flight. The tip vortex is displaced outboard from the winglet due to the decrease in outboard cant angle at the transition.
1. A wing/winglet combination comprising a wing having a distal end and a reference plane; and a winglet comprising a root connected to the distal end of the wing, an upwardly angled section, a tip positioned above the reference plane of the wings, and a transition between the upwardly angled section and the tip at which an outboard cant angle of the winglet decreases relative to the reference plane of the wing, wherein the outboard cant angle at the tip is at least 0 degrees.
2. The wing/winglet combination of claim 1 wherein at least part of the winglet is continuously curved and includes a point of inflection at which the span-wise curvature of the winglet changes sign.
3. The wing/winglet combination of claim 2 wherein the outboard cant angle of the winglet decreases continuously through the transition.
4. The wing/winglet combination of claim 1 wherein the winglet has a distal section between the transition and the tip, and wherein the distal section makes an angle of 90 degrees (+/−15 degrees) with the upwardly angled section of the winglet, when viewed perpendicular to a span-wise direction of the winglet.
5. The wing/winglet combination of claim 1 wherein the outboard cant angle decreases by 90 degrees (+/−15 degrees) through the transition.
6. The wing/winglet combination of claim 1 wherein the outboard cant angle of the winglet is less than 20 degrees at the tip.
7. The wing/winglet combination of claim 1 wherein the outboard cant angle of the winglet at the tip is lower than the average outboard cant angle of the winglet.
8. The wing/winglet combination of claim 1 wherein the span-wise curvature of the winglet reaches a maximum at the transition.
9. The wing/winglet combination of claim 1 wherein the winglet has a continuously curved leading edge and a continuously curved trailing edge.
10. The wing/winglet combination of claim 1 wherein the winglet is swept back relative to the wing.
11. A wing/winglet combination comprising a wing having a distal end and a reference plane; and a winglet comprising a root connected to the distal end of the wing, an upwardly angled section, a tip positioned above the reference plane of the wing, and a transition between the upwardly angled section and the tip at which an outboard cant angle of the winglet decreases relative to the reference plane of the wing, wherein the spanwise curvature of the winglet reaches a maximum at the transition and decreases between the transition and the tip.
12. A wing/winglet combination comprising a wing having a distal end and a reference plane; and a winglet comprising a root connected to the distal end of the wing, an upwardly angled section, a tip positioned above the reference plane of the wing, and a transition between the upwardly angled section and the tip at which an outboard cant angle of the winglet decreases relative to the reference plane of the wing, wherein a distance between the root and the tip in a spanwise direction of the reference plane is less than a distance between the root and the tip in a height direction perpendicular to the reference plane.
13. A wing/winglet combination comprising a wing having a distal end and a reference plane; and a winglet comprising a root connected to the distal end of the wing, an upwardly angled section, a tip positioned above the reference plane of the wing, and a transition between the upwardly angled section and the tip at which an outboard cant angle of the winglet decreases relative to the reference plane of the wing, wherein the upwardly angled section has a substantially constant cant angle.