Paul, and George in particular,

To my knowledge the AIXRO Aero eccentric shaft is not water cooled.
It has just got some larger diameter axial holes in the eccentric
and is hollow all the way through the centre to reduce its weight
considerably.

If you want to fit a water cooled e.-shaft to a charge cooled
engine you either have to:
a) limit the coolant within the centre of the shaft - if you
want to maintain the axial air passages in the eccentric, see attachment,
or

b) you have to do away with all the air passages in the eccentric
and need to get all the charge through the rotor tips. To be able
do so you would need the maximum cross section in the rotor tips,
what MWE, Aixro, and RotaMax rotors are miles away from, see attachment!

I have a very clear idea of what such a rotor would look like and
still hope to get one supplied for my own project some time before too
long...

Regards,

Martin.

Martin,
I'm no expert on the different  rotary configurations, but sound like you
have considerable experience.
It may be with the smaller engines like the Rotormax and Aixro there isn't
the stresses on the engine such as the Mazda, nor the emphasis on longevity,
but as Paul suggests you can't go wrong with the Mazda type surfaces, steel
lined rotor housings and buggered if I know what (BIIKW) on the Al end
housings - I would suggest steel, or ceramic filled al.
We would all appreciate your research results, if only for the knowledge. I
certainly for one would like to know more about your project as it
progresses.
At this point in time while convalescing, I am racking my brain in an
attempt to understand how Powersport made those light weight chrome molley
housings. The beauty of this is that their as light as Al and with a great
wear surface.
All the best with the project Martin.
George (down under)