On Fri, 14 Sep 2007 12:21:17 +1000, Jordan wrote:

The challenge is how to control the things so they don't spin too fast,
but still be able to start in a light breeze.

What RPM is "too fast"? What wind speed is needed to reach this given
the design (Savonious, right?), and, how often is it exceeded locally?

Of course, cost matters.

Of course.

All comments and suggestions welcome.

Depends on which type of rotor you're building. A drag-driven one
(Savonious) will have a very different answer from an, sorry, can't
remember real name, google "eggbeater wind turbine" design.

alt.energy.homepower might be a really good place to ask this question.

Hope this helps,
Dave Hinz