@ Technoman
At this Link is a Picture of a Wire and the Magnetic field.
Wissen Magnetmotor.at
I would be intrested, how the Field looks like at different Coils, like bifilar, single wired, or only in one Direction wounded.

And yes, its maybe not a good idea to bring Alu to Magnetic Fields.
I did make a Cd and did glue around it Magnets.
When i let them turn ( the Cd is on a Fan attached) and hold a Alu disc over it, it slows the Motor down to close still standing.
When it both turn at same Speed, i think it doesnt make a lot different,
because i had another Aludisk under the Cd glued.
But if one Part is standing, it slows it totally down.
Not sure, if the Alu-rotor at DC motors is an advantage, or disadvantage, that the Iron is enbedded at Alu.