| 摘要 |
PROBLEM TO BE SOLVED: To provide a drag type windmill having an automatic direction control cover capable of applying a direction control function to the cover itself and realizing simple and light weight structure.SOLUTION: A drag type windmill 10 having an automatic direction control type cover includes a float 13 arranged below a plurality of air receiving bodies 23A to 23D and rotatable around a vertical axis and a cover member 26 fixed to the upper surface of the float 13 to cover the air receiving body 23A placed at a side receiving air at a prescribed relative position to the wind direction. The cover member 26 is stayed at a prescribed relative position by the fact that an acting line of fluid force acting on the cover member 26 with wind passes above a central axis C1 of the float 13 and in turn when the wind direction is changed, the acting line is replaced from the central axis C1 of the float 13 to generate a rotation moment, it is integrally rotated with the float 13 and returns to the prescribed relative position. |
