In “A&F” No 15 of 2011 I’ve read an article «Self-made light» about how Nikolay Budilin has constructed the self-made wind generator.
I’ve recollected how in 1966 year on a field camp roof there was «a wind generator». It was constructed by the tractor driver. The generator reminded the big weather vane. Behind the generator there was the long "tail" made of plywood. The tail showed, where the wind blows. Directly under the generator the tractor headlight hungs. The headlight well shone, when the good wind blows. In the rest of the time light from a headlight was weak. But this weak light was very useful in the field.
As the tractor driver spoke, the generator ("dynamo") is from a broken ancient tractor, the airscrew ("propeller") from an ancient plane. The airscrew has been set directly on a generator shaft.
I remember, this «the wind light» lit very long. I think that at small improvement, it would be possible to receive from it more FREE light.