ORIGINAL: warhwk
I think, unless proven otherwise, that the Uni-flow type tank adds no measureable pressure to the fuel, thus fuel pressure is the same at the end of the flight as it was in the beginning.
That's EXACTLY the purpose of a uni-flow tank... it's not meant to ADD pressure to a tank.. In a normal tank it will always get leaner as the tank empties out... With uni-flow, the pressure stays equal throughout the duration of the tank, so the mixture stays more even throughout the tank...
Here's a link that explains the principles behind it... it's fairly easy to follow...
http://www.fraserker.com/heli/uniflo...flow_works.htm