Abstract: A rotational power transfer device includes a rotatable shaft, a plurality of arm structures attached to the shaft and extending radially outward from the shaft, a plurality of panel members attached to the arm structures and hanging downward therefrom, and an energy converting member for converting energy to electricity. Another vertical turbine is includes a rotatably driven power maker using panel members connected to a drive shaft such that the panel members are laterally disposed from the drive shaft in a spaced relation therefrom. A wind power generation system includes a turbine and roof top wind collector.