| 摘要 |
This invention relates to an adjustable airfoil which in one embodiment includes a pivotal mast having laterally extending spaced upper and lower arms. Between the arms is a vane which is rotatably mounted on the mast and has a luff slot at its aft end for receiving the forward end of spaced battens connected to flexible sail panels. The panels are provided with inserts at their forward ends sewed in such a manner as to cause the panels to fold in accordion fashion when they are lowered. The sail is raised and lowered by a halyard which may be either in the form of an endless loop mounted adjacent a positioning cable extending between the aft ends of the arms or it may extend forwardly and down through the mast and back to a control station, such as the helm of a sailboat. Contouring arms are pivoted between the aft end of the vane and travelers moveable along tracks mounted in the upper and lower arms for increasing or decreasing the contour of the airfoil so as to be able to form a configuration similar to a spinnaker when sailing before the wind. In one embodiment, luff flaps extend between the vane and the forward end of the sail panels to form a smooth contoured surface on the airfoil at this position for smooth laminar airflow. In another embodiment, a double luff slot arrangement in the vane includes a forward luff slot to receive the ends of battens between the panels and an aft luff slot to receive the luff edge of the sail panels. A plurality of spaced shackles contour the sail panels to change the contour of the airfoil to fit different sailing conditions.
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