I never thought of measuring how long 40 turns on the coil is(I think it's 30').
As for furling, The blade pitch changes automatically at a preset speed via a governor using a spring and cams.
So that way the wings can stay facing the wind, but no chance of overspeed.
And yes, there is one more overspeed protection, via 16f84,a tach, which If the turbine should overspeed, the power gets dumped in a large load, like two 1500w baseboard heaters mounted on the tower.
With the help of a microcontroller, the heaters in the house also get controlled, and also water heater.
By using the mill this way, no fancy battery storage ect... is needed. The power goes thru a homemade transformer,(which still needs to be done), to up the volts, and directly to heating element.
If volts vary 20-40%, who cares, the energy is not wasted, as a load like a heater(with no fan), will either run slowly or heat up quickly as the voltage changes.
In a 220v baseboard heater, put in 120v and you will get heat out of it, just not as hot or quick as if it were 220v.
Anyways hope this clarifies a bit of my project.
BTW, you never gave me your opinion on fiberglassed wings?
Thanks