Hi -
How much power can you get...
The diameter of the blade is the main factor here. 2.4 meters, if you build the whole machine well might do 150 watts @12.5mph and perhaps 700 watts @ 22mph - give or take a bit, if you build it very well and it's all fairly efficient.
Here is an informative page:
http://www.greeleynet.com/~cmorrison/windcalc.html
Regarding your comments about the alternator. It sounds like you're planning a dual rotor design. The output from your alternator at any given rpm will have everything to do with the flux through the coils, so the size and strength of the magnets are perhaps the most important factor.
The windings have to be about right too - but the nature of the windings (number of turns and size of wire) will be dependant on the voltage of your system, and again... the magnet you use. The smaller the magnets are, the more windings you'll need, the smaller the wire will have to be, and the higher the resistance will be so... the less efficient it will be.
There has to be some resistance in the system however - a certain amount of resistance will allow the power curve of the alternator to match that of the blades. I'm to thinking it might be wise to make the alternator a little on the low resistance side, get the cutin speed right, and make sure that the alternator is perhaps a bit too powerful for the blades, and then you have flexibility to add resistance to the line if needed. It may cost a bit more in magnets, but it may allow you to use a thinner line. My guess is in some cases the savings in the line will equal or outweigh the xtra cost in magnets, and... since there must be heat generated somewhere (because there has to be some resistance in the system)... I think it may be better to have it in the line, than in the alternator.
So in summery: "6 coils @ 150turns/coil (#15) and 16 magnets (8 on each side of coarse!!)"
That really means nothing and nobody could speculate about it without knowing details such as, the size of the rotors in the alternator, the width of the airgap, the size, shape, and strength of the magnets used, and the system voltage.
