Actualy, we had in mind something like my car wheel, something like this:
http://img212.imageshack.us/img212/7366/zantaee0.jpg
A few days ago i read some posts, some of them vawtman's posts and i learned much.
I'll try to find his posts.
We are making the rotor this way (double ring) trying to decrease the weight of it by not using
steel plates.
The metal pieces wich hold the rings together are very strong and the system is very
stable and light, hopfully it may turn easy.
The stator is not a problem.
We were looking here in this site for gap issues, gap between rings, dont know much how
to find the best gap, how to calculate it and we work with trial - error method.
I am new here, i'm sure some posts exist but its hard work digging posts.
Anyway, thanx for your answers.