Some $300 wind turbines off Ali baba that put out 300 watts or something. It was kind of like a propeller diameter 1m mounted to a little dc motor that was mostly bearings.
We mounted it on a pile to a shed made of metal covered foam panels, the whole shed blew over. Guyed it down after that.
Maybe 1m was the radius, this project was more than 15 years ago. The point was instead of dead batteries during cloudy times the wind complemented nicely and the batteries were charged and our load powered.
We mounted it on a pile to a shed made of metal covered foam panels, the whole shed blew over. Guyed it down after that.