Abstract: A rotary aircraft includes a cylindrically tubular hub mounting a plurality of outwardly extending, resiliently flexible blades. The blades are uniformly spaced around the hub and its central axis and fixed in pitch. Outer tips on each of the blades are downwardly turned and outwardly turned sufficiently to balance the lift generated by the blades from air striking the aircraft horizontally when the aircraft is in hover to provide passive stability to the aircraft. A pair of propellered electric motors are mounted on a diametrically opposing pair of the blades, pitched transversely to the central axis of the hub and to a plane perpendicular to the central axis, to simultaneously provide both lift and rotation. A battery supplies all power used by the aircraft while radio control circuitry in the hub permits variation of the power supplied to the motors for altitude control of the aircraft.

Abstract: A flight system capable of passively stable hover comprises an apparatus defining a vertical axis, and including multiple upright ducts spaced about the axis; fluid momentum generators in the ducts to effect flow of fluid downwardly in the ducts; and fluid flow deflector structure in the path of the downwardly flowing fluid, and angled to deflect the fluid flow away from the axis, in such manner as to provide stability in hover of the apparatus.

Abstract: A flight system capable of passively stable hover and horizontal translatory flight, comprises an apparatus defining a vertical axis, and including multiple ducts with substantially vertical axes in hover mode, spaced the axis; fluid momentum generators in the ducts to effect flow of fluid downwardly in the ducts in hover; and fluid flow deflector structure in the path of the flowing duct fluid, and angled to deflect the fluid flow away from the axis, in such manner as to provide stability in hover of the apparatus, as well as stability when the entire device is tilted through approximately 90.degree. to execute horizontal translatory flight.

Abstract: A water turbine for open stream use featuring a vertical-axis cross-flow turbine in which cyclically-pitching blades are supported from one end only to permit the supporting structure and power generation gear to be supported out of the water. In preferred embodiments, there is independent pitch control of the turbine blades to make the blades responsive to the instantaneous flow in their vicinities.

Abstract: A wind turbine apparatus in which a plurality of wind responsive elements are movably mounted, such as by being pivotally mounted, on a movable means which produces rotary motion. The positions of the wind responsive elements are arranged to provide a drag force on at least one of the elements in response to the wind when the speed of rotary motion is below a predetermined level so as to produce a starting force to initiate and maintain the rotary motion. When the speed of the rotary motion exceeds such predetermined level the positions of such wind responsive elements are such that a lift force is provided thereon in response to the wind so that the rotary motion can achieve speeds which are considerably higher than those achieved by the starting force.