You made me think about it a bit harder, Greg. I think If Tank#1's vent (feeder line from #2) is down in the fuel, it's simply another way to do a parallel connection. The fuel would be consumed in (presumably) equal amounts from each tank, negating the aircraft's unusual attitude advantage of sequential drainage during flight. I'll make a model of this with some junk sullivans I have lying around to see if this is true. Great discussion. I bet you guys can't wait until I move on to batteries. ha ha ha ha!!!!
Update: I made a dual tank mockup and tested with water. See the pic below. I was only partially correct. With tank#1 (nearest engine) having it's vent (feeder line) bathed in fuel pointed down, all fuel fills to the last tank (#2), completely bypassing tank #1. Obviously an untenable situation.
When Tank#1's vent is pointed UP as suggested by Greg, the fuel first fills Tank#1, and then sequentially tank #2. During flight, the fuel first drains tank#2, and only starts draining tank #1 after #2 is empty. Good for aerobatics later in a given flight. Thanks to Jetflyr for giving me the incentive to try this on the ground rather than airborne. Here's a pic of the test rig. It's in the drain mode, you can see tank#1 is all full, and tank#2 is already half
empty.
