The present invention pertains to an apparatus to improve the efficiency and performance of an aerodynamic lift structure for use on sailing devices. A two-sided, spaced apart sail structure is provided with resiliently deformable struts for each side, attached at one end to a beam, fixed to the mast of the sailing device, the mast being rotatable about its vertical axis in either direction relative to vertical planes along the longitudinal axes of the sailing device and the boom in a manner whereby a cam action is produced by the beam to deform or bend the struts in a manner so as to vary the camber of the wing sail, the amount of camber of one side of the wing sail being greater than the concave curvature of the opposed side thus producing an airfoil configuration. Provisions are made to permit translation of the two main surfaces of the wing sail as well as the surfaces at the clew corner while maintaining proper tension in the surfaces, and an aerodynamic seal is provided along the trailing edge of the wing sail. A horizontal control bar is attached to the mast to control the pivotal movement of the mast by a block and tackle attached between each end of the bar and the boom.

A hydraulic drive system for a wing sail on a vessel, comprising a rotatable frame at the base of the mast and hydraulic cylinders connected between the frame and the ship's structure to cause rotation of the frame in either direction through a limited angle, and a brake is provided on the frame for transmitting rotation of the frame to the mast when the frame is rotating in a direction that it is desired for the mast to rotate, and a brake is provided for preventing rotation of the mast when the frame rotates in the opposite direction, whereby the mast may be rotated through a desired angle by oscillatory movement of the rotatable frame.

A wingsail structure wherein the sail comprises a plurality of ribs encircling the mast and is guided slidably along the mast. A fabric skin is wrapped around the ribs. In a preferred embodiment, the mast is provided with at least two opposed, parallel longitudinal grooves forming respective guides for running carts attached to the ribs and is formed by a pair of parallel slats interconnected by cross-beams, said slats having an airfoil shaped cross-section.

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.

A sail assembly of variable profile, reversible and collapsible, comprising a mast on which are mounted ribs set apart one from the other, each one being constituted of two flexible laths joined together by hinge members, the ribs being covered with a supple material, such as for example sail cloth. Each rib includes a slide piece on which are pivotally mounted the two flexible laths and on which a mast is slidably mounted, the mast being fast in rotation with the slide and being adapted to be driven in rotation, the slide piece being provided at the back with a first cam which is fast with a shaft driven in rotation and comprising two arms connected together by transmission members pivotally mounted on the rear portion of the flexible laths. The invention finds an application in the production of sail assemblies of variable profile.