Tail size and weight (Mini Turbine)

[Jens]

Hi everybody,

I recently moved to an area where electricity is expensive and wind is plenty so I started looking into making a turbine of my own. It's a mini 2' turbine made pretty much with the same layout as on Dan's machine, I know it is small and I won't see much production from it, but I'm learning.

I'm using 12 x 3/4" disk mags, 9 Coils with 140 windings, so it looks the same, but mini. Do I need to look into furling tails with this little baby? If yes, how should I scale the tail? I guess that weight will have a say too. If no, is there an other way to effectively/Automatically stop it at high winds (winds here easily hits 30mph)?

/Jens

[Jens]

I found the formula that Ed wrote in a threat.

So, I get it to 40 cm of tail with a weight of 140 grams.

And grabbed from thin air the tail size: 1/2 sq ft?

I just have one last question:

Is the length of the tail actually the arm i.e placement of C of G?

[DanB]

You shouldn't assume that 140 windings will be correct here.  You need to build you magnet rotors and then wind a test coil and stick it in there/see how many windings you really need and then pick a suitable size of wire for your actual coils that let you get the right number of windings.  I think you'll want cutin speed for a 2' blade somewhere around 600 rpm give or take a bit - so shoot to get the 'desired' voltage at the right rpm to make your blade happy.

[Jens]

Don't worry I'm not assuming anything. 140 was the guesstimate that popped out after pouring the numbers through the formulas, but I can see I had my Cutin speed set too low. I'll try again.

Thanks,