Nick Kitchener wrote:That thing likely blew apart in the first storm because there is no mechanism for governing the speed that they spin at. Many designs include a mechanism that changes the blade angle based on the centrifugal force so the faster it spins, the less turning force the blades create.
He has actually been using it for a number of years now. On his site he talks about a storm with 50 mph winds that broke some of the fins, and the mods he created to fix it. The last update was 2012 I believe, and that is at least 5 years after he built it. I believe he built it for $140. Not bad I thought.