To find the approximate prop speed at various tip speed ratio's here is a quickie formula...
Windspeed x 88 / ( diameter x 3.14 ) x TSR = rpm
So lets say your 5 ft prop will be designed to run at a tip speed of 4 and you want to find the rpm at around 7 mph, which might be the cut in speed of the alternator....
7 x 88 / ( 5 x 3.14) x 4 = 157 rpm
At a tsr of 6 it would be
7 x 88 / ( 5 x 3.14) x 6 = 235 rpm
You'd want your cut in speed to occur at around 157 rpm with a TSR of 4 or at 235 with a TSR of 6. It might be easier to use the higher rpm when winding the stator using small magnets. It will take a considerable amount of turns to get 12 volts at cut in. So, the formula I use for the alternator is...
NARBP*2 = voltage
where...
N = total number of turns per phase
A = area of 1 magnet ( in sq meters - sq inches x .000645 )
R = revolutions per second ( rpm / 60 )
B = magnetic flux in Tesla ( gauss / 10000 )
P = number of poles ( only count one disc on a dual rotor )
B is the only one that is usually difficult to measure unless you have a gauss meter. If your using neodymium and you keep the air gap to around .625 to .75 then the Tesla penitration would be about 0.5 . This is measured from an N35 grade neo.
So if we change the formula around to find the number of turns it would look like this...
N = voltage / ( A x R x B x P x 2 )
Your using 1 inch diameter magnets to the area is .7854 sq inch ( 1^2 x .7854 ) then we change it to sq meters... .7854 x .000645 = .000506 sq meters.
R will be the higher rpm of 235 or 235/60 = 3.91 revolutions per second
B we'll use the 0.5
P your showing 12 poles
So...
N = 12volts / ( .000506 x 3.91 x .5 x 12 x 2 ) = 505 turns of wire to make 12 volts at 235 rpm
Now you have 3 coils in series per phase so you can divide the total number of turns by 3 to get turns per coil 505 / 3 = 168 per coil
If your going to wire it in star you can divide the turns per coil by 1.732 ( 168/1.732 = 97 turns per coil wired in star. If you made a single phase or 3 phase wired in delta then you would have to use the 168 turns per coil to get the voltage you needed at that speed.
Hope that helps
.