The classic is taking an oil drum, cutting it in half, and using that
as a Savonius rotor. Then you get an alternator from a car, and there's
your actual generator. The axle sticks up into the air, where the halves
of the oil drum collect the wind and turn the alternator.
Ahhh, I remember reading about these.
After university, you know those years when you fiddle about back home at
your parents for 12-months, I played with some of these things.
One of the biggest hurdles is the sheer power of the wind. I made mmmmmmm.
Having trouble finding anything on line these days... All commercial carp.
Anyway, the thing just fell to pieces in the wind. I used 1cm threaded rods
to hold the paddles as it were to the rotating axle. The result was a
tangled mess. It's certainly not as easy as it sounds.
The trouble with the car alternator is that it needs to be spun sufficiantly
fast to generate energy, and the coil also needs to be energised. A
rotating propeller needs to be stepped up to about 1000 revs+ certainly via
a chain/gear assembly. That's assuming there is sufficiant wind to get it
spinning.
From what I remember the savonius rotors work in very low wind speeds and
also generate alot of torque. I wish I could find this example.
Looking....
Darrieus turbine!!!!!!!!!!
http://www.reuk.co.uk/OtherImages/vawt.jpg
That's pretty much what I tried to build.