a vertical windmill employing aerodynamic lift includes stators that form an omnidirectional diffuser and can rotate out of the wind to reduce the destructive tendencies in high winds . a braking mechanism included in the windmill uses rotation of the airfoils to reduce the lift caused by the wind and disengagement of the airfoils to reduce nearly all lift on the airfoils . centrifugal force is used to activate the brake in high winds , both to slow the rotor speed and , in extreme winds , to stop the rotor . a motor is provided to drive the windmill to simplify controls and increase energy production .