Wow! A very interesting read to say the least. Thank you gentlemen for keeping it civilized. I found this thread by doing a search on Uni Flow Tanks. Something I'd never heard of before in almost 20 years of modeling, until today, while reading another thread. I've had an OS 46FX with a Pitts style muffler on it, and currently have an OS 46AX with the standard muffler on it. The older engine doesn't seem to want to respond to needle adjustments at all (usually lean with several turns out) and the newer engine tends to die after about half a tank. While there certainly may be other factors involved in the poor performance of both engines, and there probably is (I've never been good at really tuning an engine[:@]), I think the UniFlow setup has great merit. It sounds to me as though needle valve adjustments for atmospheric conditions would be more or less a thing of the past.

I'll throw this out for discussion:

Considering my Pitts style muffler; Would this tank setup have any influence on the issues caused by the Pitts muffler? I've been told by others, that the problem with Pitts mufflers is that they don't usually provide enough back pressure to the tank unless one of the exhaust ports is either partially blocked or plugged all together. Is this reasonable?