Abstract: A vertical axis wind turbine with a symmetric airfoil having a concavely curved tail portion defining a trailing edge angle of between 0° and 5° on either side of the chord, a maximum thickness center point between 26% and 34% of the length of the chord from the leading edge, a leading edge curvature ratio (D1/D2) from 0.42 to 0.50, and a ratio of maximum thickness to chord length T/C from 0.12 to 0.19, preferably 0.16. Advantageously, the rotor may have helical blades defining a cylindrical swept envelope with a positive angle of attack and a solidity ratio NC/D from 0.125 to 0.270, and is governed at a tip speed ratio from 2.25 to 4.00.

Abstract: A vertical axis wind turbine with a symmetric airfoil having a concavely curved tail portion defining a trailing edge angle of between 0° and 5° on either side of the chord, a maximum thickness center point between 26% and 34% of the length of the chord from the leading edge, a leading edge curvature ratio (D1/D2) from 0.42 to 0.50, and a ratio of maximum thickness to chord length T/C from 0.12 to 0.19, preferably 0.16. Advantageously, the rotor may have helical blades defining a cylindrical swept envelope with a positive angle of attack and a solidity ratio NC/D from 0.125 to 0.270, and is governed at a tip speed ratio from 2.25 to 4.00.

Abstract: Vertical axis turbine apparatus is described in which a rotating blade turbine member mounted on a fixed base includes one to fifty, preferably two or three, upwardly and outwardly inclined spars. On each spar is set at least one aerofoil or hydrofoil section blade. If there is more than one spar, the spars are preferably held to one another via a plurality of guy wires.

Abstract: A vertical axis wind turbine has a stationary circular core and a rotor rotatably supported about the stationary core. The rotor has a radially extending rotor arm with a wind engaging blade locate at its distal end. The blade has at least two straight blade sections of which at least one blade section is inclined obliquely at a first angle.

Abstract: A shaftless vertical axis wind turbine has a stationary hollow core having inner and outer circular walls with a void between the inner and outer walls. A rotor is rotatably supported about the core and has a plurality of radially extending rotor arms each having a wind engaging rotor blade located at a distal end.

Abstract: A wind deflector for a wind turbine has a vertical wind deflecting surface movable in a circular path about the wind turbine for facing a prevailing wind direction.

Abstract: A wind turbine structure has a vertical core that supports multiple stages of rotor support frames and power generating units, each rotor support frame comprising an annular carousel rotatably located about the core and having at least two radially extending arms, and at least one pair of propeller-type rotors located respectively at distal ends of the radially extending arms. Each rotor support frame can rotate around the vertical core independently. Each rotor support frame further comprises a wind deflector.

Abstract: Vertical axis turbine apparatus is described in which a rotating blade turbine member mounted on a fixed base consists of one to fifty, preferably two or three, upwardly and outwardly inclined spars (F). On each spar is set at least one aerofoil or hydrofoil section blade (S). If there is more than one spar, the spars are preferably held to one another via a plurality of guy wires (T).