Wing tips and wing tip construction and design methods
An air-redirection formation for a tip portion of an aerofoil such as an aircraft wing includes: a first portion, which includes a first surface which forms a continuation of the aerodynamic lifting surface of the wing, and which is for directing vortices away from the aerofoil; and a second portion, which is spaced from the first portion and which is positioned to generate uplift due to the directed vortices.
1. An air-redirection formation for a tip portion of an aerofoil which includes:
a first portion, which includes a first surface which forms a continuation of an aerodynamic lifting surface of the aerofoil, and which is for directing vortices away from the aerofoil; and
a second portion which is connected to the first portion by a connection structure which is canted downwardly and swept back, the second portion including a second surface spaced from the first portion by the connection structure and which is positioned to interact with the directed vortices
wherein, defining a horizontal plane of the aerofoil by chords extending from the leading edge of the aerofoil to the training edge, the first surface is in the horizontal plane.
2. An air-direction formation according to claim 1 which is provided as a device which is separate from, but connectable to, a tip portion of the aerofoil.
3. An air-direction formation according to claim 1 which is connected to an aerofoil.
4. An air-redirection formation according to claim 3 further including a controllable actuator for controlling a rotational and/or translational position of the first and/or second portions of the formation relative to the aerofoil.
5. An air-redirection formation according to claim 4 in which the actuator is operative to control a rotational position of the first and/or second portions of the formation about a span-wise axis of the aerofoil.
6. An air-redirection formation according to claim 4 in which the actuator is operative to control a rotational position of the first and/or second portions of the formation about a chord-wise axis of the aerofoil.
7. An air-redirection formation according to claim 4 in which the actuator is operative to control a rotational position of the first and/or second portions of the formation about a yaw axis of the aerofoil.
8. An air-redirection formation according to claim 4 in which the actuator controls a said rotational and/or translational position about a rotational axis by deforming a portion of the formation.
9. An air-redirection formation according to claim 3 , in which the second surface is within 90 degrees of the horizontal plane.
10. An air-direction formation according to claim 3 in which the first and/or second portions of the air-redirection formation extend parallel to an elongation axis of the aerofoil.
11. An air-direction formation according to claim 3 in which at least the first portion of the air-redirection formation extends rearwardly from the main surface of the aerofoil in a direction opposite to a direction in which the aerofoil passes through ambient air.
12. An air-direction formation according to claim 3 in which the connection structure is connected to the first portion at a location on the first portion furthermost from the aerofoil.
13. An air-redirection formation according to claim 3 , in which the second surface is within 15 degrees of the horizontal plane.
14. An air-redirection formation according to claim 3 , in which the second surface is within 45 degrees of the horizontal plane.
15. An air-direction formation according to claim 1 which is connected to an aerofoil, and in which the connection structure has a smaller maximum chord length than the maximum chord length of the first and/or second portions of the air-redirection formation.
16. An air-direction formation according to claim 15 in which the connection structure comprises at least two joined connection elements,
a first one of the connection elements being connected to the first portion of the air-redirection formation, and having an elongation direction which extends away from the first portion of the air-redirection formation, and which has a component transverse to the horizontal plane in a first direction; and
a second of the connection elements being connected to the second portion of the air-redirection formation, and having an elongation direction which extends away from the second portion of the air-redirection formation, and which has a component transverse to the horizontal plane in the first direction.
17. An air-direction formation according to claim 1 attached to a anhedral wing.
18. An air-direction formation according to claim 1 wherein, in a direction away from the aerofoil, a sweep angle increases and, at the second portion, the sweep angle reduces again.
19. An air-direction formation according to claim 1 wherein, in a direction away from the aerofoil, both sweep angle and cant increase and then reduce for the second section.
20. An aircraft having a plurality of wings, a tip portion of each of the wings including a respective air-redirection formation which includes:
a first portion, which includes a first surface which forms a continuation of an aerodynamic lifting surface of the wing, and which is for directing vortices away from the wing, and
a second portion which is connected to the first portion by a connection structure which is canted downwardly and swept back, the second portion including a second surface spaced from the first portion by the connection structure and which is positioned to interact with the directed vortices
wherein, defining a horizontal plane of the wing by chords extending from the leading edge of the wing to the training edge, the first surface is in the horizontal plane.