Abstract: This invention relates to a vertical axis sail-type windmill power transfer device for efficiently harvesting wind power by increasing the effective surface of interaction with the wind where the sails are formed by a plurality of pairs of blades permanently attached to freely rotating horizontal rods penetrating the vertical output shaft with pivot offset of the center of the weight which causes the blades to self-adjust when impacted by wind so that one blade assumes a driving position while the other—a leeward position. The invention has a modular-type structure which permits for a variety of configurations and allows for photovoltaic cells to be placed on the blades in order to complement the production of wind energy with solar energy.

Abstract: This invention relates to a vertical axis sail-type windmill power transfer device for efficiently harvesting wind power by increasing the effective surface of interaction with the wind where the sails are formed by a plurality of pairs of blades permanently attached to freely rotating horizontal rods penetrating the vertical output shaft with pivot offset of the center of the weight which causes the blades to self-adjust when impacted by wind so that one blade assumes a driving position while the other—a leeward position. The invention has a modular-type structure which permits for a variety of configurations and allows for photovoltaic cells to be placed on the blades in order to complement the production of wind energy with solar energy.