Sails

This design in the quote below is a vertical mount windmill using sails, and seems pretty practical. One of the problems I've encountered with horizontal mount windmills is the fabrication problems for the blades. If you need to replace a broken blade this becomes a problem, getting the proper shape, pitch, etc. If you’re working with sails finding material should be easier, particularly post pole shift.

Richard Pierson wrote a book back in 1978 which I kept a copy of. It is entitled "Build-It Yourself Natural Energy Sources: Solar, Wind & Water Power Made Easy" Chapter 10 of that book describes in great detail how to build the Vertical-Shaft Pierson Wind Turbine. I basically a modified S-rotor system with aluminum or galvanized sheet metal scoops or half-cylinders as rotors, but it also has these neat stationary vectoring vanes to scoop up even more wind into the rotor. These are really just fixed walls pointing at a tangent to the rotor buckets. He calls these fixed walls stator vanes, or just stators. That is the best part of this design, I think because it allows the configuration to begin putting out power in 5 MPH winds or below, depending on the length of the stator (wall) from the vertical shaft out to the end of the stator. You have to rig up a generator and some gears, and for high winds you might have to figure out how to shut it down or rig up a governor, but it looks do-able for a tinkerer like myself.

Here's some more info on vertical axis wind turbines/mills. Think greenhouse pumps and fan power, and heat, and chillers, etc.

http://www.greenwindmill.com/
http://www.windmillworld.com/links/verticalaxis.htm
http://www.southcom.com.au/~windmill/
http://home.earthlink.net/~fradella/green.htm

Offered by Stan.