Sounds like quite an experience. Yeah, turbo prop airplane is a good description when these things get going, really took me by surprize, my first time seeing a modern wind turbine in action. After seeing this I'm really starting to understand why DanB likes the idea of a big slow turning rotor which turns out of the wind rather early. I think I'll be heading in that direction myself in general. However, I may make some tiny fast ones to put out in the yard to run lights, pump water, etc. and just to experiment with. Anyway, this stuff is a lot of fun in several ways and pays you back for your investment, my kind of thing. :-)
Kevin