RE: CO2 powered engine
You may need to contact someone within the Flying Aces Club for better Information on CO-2 powered aircraft. Like pipe up at the Yahoo group that SAM runs. A few members of the FAC still operate the Co-2 engined aircraft today. They usually give a demo- at and AMA sponsored (inside) event.
The end of the CO-2 bottle was normally aimed downwards, and the end jsut below the centerline for the engine, so as not to allow raw gas into the cylinder, but instead only the gaseous mix then. The placement and note of this is shown on many aircraft plans of the 1950's. The cylinders for the CO-2 cylinders were normally well in excess of the noted 250 PSI.
Wm.