Vertical axis sail bladed wind turbine

In a vertical axis turbine comprising a vertically extending, rotatable shaft;

• upper and lower blade attachment means for attaching at least one blade to said shaft, and a power absorbing load device coupled to said shaft;
• the improvement wherein said at least one blade comprises a flexible sail blade, made of fabric or film so as to have no substantial resistance to bending and thus to be limp under no load, and so that in operation, said blade cambers inwardly towards the axis of rotation of the shaft when the blade is in an upwind position and cambers outwardly away from said axis of rotation when the blade is in a downwind position, and attached at the ends thereof to said shaft by said upper and lower blade attachment means and deployed and stabilized in operation by the centrifugal forces produced in response to rotation of said blades about the vertical axis of said shaft, whereby, in operation, aerodynamic forces acting on said sail blades can be transmitted to shaft without generating bending moments, said blade having at least one flyweight secured thereto.