From theory, I remember that EMF induced is a function of the rate of change of magnetic flux. A generator is typically a changing magnetic field applied to a bunch of diamagnetic wires wound closely together over a laminated core. Part of the reason for the close winding is probably to expose as many turns as possible to the changing flux.
I'm thinking about using a fine copper mesh like this one:
That mesh was earlier an antenna on an old old old valve radio instead of a coil. It's also used in Faraday cages.
What would happen if I used this the micro turbine I'm thinking to attempt? Worst condition is probably a brown-out if the induced current follows different paths ....
EDIT: The intent with using the mesh is as an experiment to try something different (+: A friend has a repair shop, and the facilities to do the winding if required