Lift... Drag... Angle of attack... Reynolds number...
TOUGH question that has a lot of questions of its own! What kind of wind are you expecting? What airfoil design are you using? What kind of shaft loading are you expecting (in watts or otherwise)?http://www.allstar.fiu.edu/AERO/lift_drag.htmhttp://en.wikipedia.org/wiki/Reynolds_number
I think the variable angle of attack is a great idea. The only thing cooler would be a magical variable airfoil :)
Some basic stuff to keep in mind:
Increased angle of attack generally means increased lift and increased drag.
So.. increasing lift increases your "torque" and therefore makes low-wind startup better.
But it also increases drag which will slow down your rotations (lower RPM)
A variable angle of attack that was RPM defendant would be the best but Im not sure how this would be implemented (springs and centripetal force perhaps? Active electronics?)
This would allow your turbine to accept a variety of wind conditions and even stall itself out for maintenance or high-wind conditions.
Can you post some pics or drawings? Im very curious to see your design ideas.
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