Large vertical-axis variable-pitch wind turbine

A large vertical-axis variable-pitch wind turbine, comprising a tower structure, a vertical turbine shaft supported by said tower structure, a hub structure affixed on said turbine shaft and carrying radially disposed horizontal struts, vertical blades pivotally attached to said horizontal struts, and a tail structure with a vane and a system for cyclical change of blade pitch-angle at each turbine turn, wherein the improvement comprises:

• a support means for said tail structure which support means is mounted on said hub structure;
• a tail-axle held in bearings by said support means and positioned above of and co-axial with said vertical turbine shaft, and carrying said tail structure;
• a steering mechanism in a case affixed to lower end portion of said tail-axle in the space above said hub structure, for driving a steering pivot to various positions differently eccentric to said turbine shaft along a line generally parallel with the wind direction;
• said steering pivot carrying a rotatably mounted hub for fastening a plurality of connecting means;
• and
• said connecting means between said steering pivot and each turbine blade, for blade pitch-angle control;
• whereby magnitude of cyclical variation of blade pitch-angle is dependent on eccentricity of said steering pivot position, controled by said steering mechanism, so
• that it varies at any significant change of actual wind speed, to hold the wind-to-blade incidence angle to achieve highest possible efficiency.