Sail with retractable air directing element.

摘要

A sailset comprising a leading aerofoil and a trailing aerofoil that pivots about an axis passing through the leading aerofoil. A third comparatively small aerofoil is retractable within the leading aerofoil and extendable downwind of the trailing edge of the leading aerofoil to provide a surface overlapping the leading edge of the trailing aerofoil.

Guides for the third aerofoil are preferably provided for both its leading and trailing edges, the guides comprising roller and roller tracks and/or sliding pivots.