Dear RotarySMP,
as you can see an the pictures below, the engine is completely made of graphite. Only the drive shaft is steel. The graphite I use is a special mixture for best tribological characteristic. It is also impregnated for high temperature use.
Because there is no material mix with different thermal expansion the gap tolerances from rotor to side housing are very small.
I use only centrifugal force for the vanes. I also tried th pressurize the vanes with compressed air, but it was not necessary. The vanes start tightening up at about 300 rpm. First I tried with petrol-gas mixture out of a small carburetor. When too much unburned petrol is in the engine the vanes may stick.
So I used Propane gas for all my testing.
Markus
