Abstract: Arrays of parallel, substantially fore and aft oriented vortex generators are positioned on the keel and rudder of a sailboat to induce vortices at the surfaces of the keel and rudder for the purpose of reenergizing the boundary layers in the water flow past the keel and the rudder to increase the lateral lift in the horizontal plane and to thereby avoid increase in drag associated with keel and rudder stall at high angles of attack with the relative water flow. Similar arrays for the same purpose may be attached to other underwater stabilizing members such as skegs, keel winglets, centerboards, etc.

Abstract: A cam cleat having opposed rotatable rope-gripping cams can be remotely operated by the action of the free end of the rope on an open rope-engaging face of a cam actuating arm, there being a rope-restraining lip overlying the rope-engaging face of the arm.

Abstract: A solar collector is disclosed comprising a glass member having a solar selective coating thereon, and a molded, glass-reinforced concrete member bonded to the glass member and shaped to provide a series of passageways between the glass member and the fiber-reinforced concrete member capable of carrying heat exchanging fluid therethrough. The fiber-reinforced concrete member may be formed by spraying a thin layer of concrete and chopped fibers such as chopped glass fibers onto a mold to provide an inexpensive and lightweight, thin-walled member. The fiber-reinforced concrete member may have a lightweight cellular concrete backing thereon for insulation purposes. The collector is further characterized by the use of materials which have substantially matching thermal coefficients of expansion over the temperature range normally encountered in the use of solar collectors.

Abstract: Ink droplets for ink-jet printing are formed in a conductive, ink by flowing ink having a ion magnetic susceptibility between the poles of a pulsed electro-magnet thereby periodically inducing eddy currents in bodies of the ink which oppose ink flow and stimulate perturbations of an ink stream having an orifice so that discrete droplets of ink are formed at a uniform distance from the orifice.

Abstract: A heliostat apparatus includes a frame which is rotatable about an axis which is parallel to the aperture plane of an elongate receiver. A plurality of flat flexible mirror elements are mounted to the frame between several parallel, uniformly spaced resilient beams which are pivotally connected at their ends to the frame. Channels are mounted to the sides of the beams for supporting the edges of the mirror elements. Each of the beams has a longitudinally varying configuration designed to bow into predetermined, generally circular curvatures of varying radii when the center of the beam is deflected relative to the pivotally connected ends of the beams. All of the parallel resilient beams are simultaneously deflected by a cam shaft assembly extending through openings in the centers of the beams, whereby the mirror elements together form an upwardly concave, cylindrical reflecting surface.