Hi Ed!
I am considering building something similar to you 500 watt kit, dual 8" rotors 12/9 arrangement.
My consern is weight. How much does the generator in the 500 watt kit weigh?
The magnets I'll use are round neo 1.20" x 3/16". Will have to make a test coil though...
Sure I'll get less power, but I've been flying an induction conversion for the past months, seen peaks of 25 amps @ 12 volts but I think it's time to move on.
It's on top of my shop's roof Jerry style, close to the house and way too much turbulence.
It is an extremely heavy unit, 2 meter prop and chain drive to the genny, must weigh about 45 lbs. Don't feel too safe putting that thing on a tall tower.
We get 15-20 mph winds here very often.
Thanks,
Warrior