Abstract: A vertical axis windmill features a wind vane assembly freely rotatable relative to an output shaft and having a first wind deflecting device for channeling oncoming wind relatively away from and towards wind reaction panel carrying spars, during those portions of rotational movement thereof relatively towards and away from the wind, respectively, a second wind deflecting device for channeling oncoming wind relatively towards such spars, during that portion of rotational movement thereof relatively away from the wind, and a wind vane cooperating with the first and second wind deflecting devices for maintaining same in desired relatively stationary positions relative to the direction of the oncoming wind, wherein the first wind deflecting device is formed with an opening fitted with an auxiliary panel directly responsive to high wind loading conditions to permit flow of oncoming wind through such opening for purposes of providing a motion retarding or braking effect on the rotational speed of the windmill thro