Thanks for all your feedback, i've written to mazda regarding the servicing required, fuel consumption, weight, dimensions, idle rpm and reliability!...just waiting for a reply.
The RX-8 car does quite good mpg so i presume it would run well for gal/hr!
Im sure there are drawbacks to this type of engine but still worth doing a project on.
Also what make/specifications are the engines that cessnas and warriors use to make comparisons with the RX-8?
thanks!