Charts, I solved that problem by going to a lawnmower repair shop and purchasing another felt clunk like the one that's used in the hopper tank. It will 'wick' the fuel up every chance it gets while in flight. I flew mine with a P80 in it, no wing tank, the fuse, hopper, AND a BVM UAT for more flight time. I could get about 7.5 - 8 minutes flying time. After landing I would have about 1/4 - 1/2 inch of fuel in the fuse tank and the hopper and UAT were still full.

Give it a shot! That problem really bothered me too. Good luck. You're gonna love that jet!