Hunkin says that the fan is actually from a blower (presumably leaf blower or similar). So I doubt it would have the problems with flexibility and stuff that you mention, John. Granted, it's still not the most efficient turbine in the world! :-) But as he said, even improving blade efficiency wasn't going to cut it. As you say, the critical part is whether you get enough wind over it, day in, day out, for it to cut the mustard.

Graham.