I have the ECI fuel injection that requires fuel return lines. I plumbed mine through the Z-brackets on the rear baffle and all the way back to the outboard bay. However, if doing it again or doing a retrofit on an existing tank I would be inclined to do what is described above. Penetrate the end plate with a bulkhead fitting and then run a tube through at least the first interior rib of the tank up high on the rib. I cannot imagine why this would not work well.If it's just the purge quantity from the AFP purge line, I would tap it into the supply line of the boost pump. If it's constant return and it needs to go to the tank, the way I did it was to remove the access plate on the tank, drill another hole in it where you want it, and I ran a piece of 3/8" line a couple bays deep in the tank to avoid foaming/splashing the fuel in the same bay where the pickup is. I just made a loop of safety wire through a hole in the bottom of the rib holes in the tank ribs (I was only able to reach 1 rib deep), and passed the 3/8" aluminum line through that loop as I put the plate back on. That will keep it from moving around during flight.
My ECI fuel injection setup umps more fuel through the mechanical fuel pump than the engine can burn so the excess flow is returned back to the supplying tank.What type of engine setup would require such a return line to the tanks? (I'm thinking diesel?)
snipped the way I did it was to remove the access plate on the tank, drill another hole in it where you want it, and I ran a piece of 3/8" line a couple bays deep in the tank to avoid foaming/splashing the fuel in the same bay where the pickup is. snipped
Did you install snap bushings or some other method of preventing the return tube from chafing on the ribs?
Charlie