I was thinking that a large truck brake drum (instead of a disk rotor) might make an effiecient rotor.
It is not really my idea I saw one that resembles this at the MRNE Fair
http://venteraenergy.com/ check out the pic about halfway down
This one also had blades that would twist in high winds so no furling was necessary --full out put up to 40 mph
Advantages the stator would be protected from the elements
better cooling --just hang a heat sink on the back of the stator
possibly better efficiency from better coil geometry
room for more magnents
better control of gap spacing
really heavy duty truck axles for strength
again I'll bet someone has tried this one already
