Go to otherpower.com, it's got everything you want to know on wind turbines and much more. You can find pictures of my two HA turbines there. Both are down wind machines and the rotor swings up and "turns" into a VA machine in high winds. Btw, when this happens the output does not drop, it just quits increasing, which is good because something would break/blow if it didn't. The only reason the VA machines can take such high winds is because they're so inefficient. I've seen my machines take 60+mph winds with no problem, except for the time the pole bent to the ground. lol That was my fault, I'm using poles that are way too small according to the experts. The pole that bent flexed every time a gust hit the rotor. Also, I've got my 10 foot diam. rotor turbine just high enough that the blade doesn't hit anyone, makes things much easier, cheaper, and less apt to be totally destroyed if it falls. In 10mph wind it'll spin several hundred rpms and maybe give 100watts. Wind over 20mph gives around 750watts. It was a very fun project, but not a huge bang for the buck like the solar collectors, which are also there to see I think.