sumisu: here's a tool that we used in Malawi. <a href="http://www.chapinlivingwaters.org/bucketkitoct.pdf" rel="nofollow" target="_blank">http://www.chapinlivingwaters.org/bucketkitoct.pdf</a> And this might be of interest to you: <a href="http://www.materialicious.com/2009/07/mini-wind-turbines-by-catapult-design.html" rel="nofollow" target="_blank">http://www.materialicious.com/2009/07/mini-wind-turbines-by-catapult-design.html</a>