> >with these numbers, I calculate that for equal volumes (we simply swap
> >aluminum for iron) the iron rotor will be 2.9 times more massive. for equal
> >masses, the iron rotor will heat 1 degK for each .48 degK the aluminum
> >rotor heats. 2.9*.48= 1.392. So, a rotor of Al equal in volume to the
> >original Fe rotor will be increase in temperature 40% more than the iron
> >rotor for a given deceleration (energy input).
What does the temperature profile look like, though? This doesn't
take into account the far-superior thermal conductivity of Al, which
will also dictate how efficiently the venting will work.
Besides, I would guess that this is dwarfed by the savings in
angular momentum due to reduced mass.