Thursday, July 3, 2014

trial fit of fuel tank

well, I bet you thought I died or something.  No, but I’ve been on vacation and/or working my tail off to catch up on the vacation hours.  Today’s posting isn’t typical: it’s not a page completion but it is a milestone worth commenting on.  I’ve been worried about my fuel lines ever since EAA Tech inspection #2.  The inspector commented that I might have some leaks since I didn’t buff the edges of my flared tubes.  Rather than barging ahead, I’ve been planning on doing some leak testing before I bury the fuel lines in wiring harnesses and flight control linkages.  

Yesterday, I was finally successful in installing the fuel tank.  I couldn’t get the thing in there until I realized that there was a cleco inside the fuselage that was obstructing a good fit.  Clearing that up made all the difference in the world.

The main fuel line was amazingly close to the nipple on the bottom of the tank and was actually “easy” to attach, once I figured out that I had to get under the plane and reach up through the access holes.  (How’s that for a “duh!” moment?)  The fuel return line?  Not so much.  It was at least 1.5” too high and about the same distance too forward.  I cut & re-flared the tube to address the first issue.  I finally had a Light Bulb Moment and loosened up all of the clamps and was able to rotate the aft clamp (which is oriented transversely) and that moved the fuel return line aft very nicely.

Below, you can see the two lines attached to the bottom of the tank.  Up front, I fashioned a couple of quick lines to “short circuit” the fuel circuit, only to discover I had the wrong size reducer.  AN819 reducer’s are specified as the larger size, not the smaller size.  When the proper AN819-6D (to 4D) reducer arrives, I’ll connect the two and put a gallon of gas in the tank and run the pump.  I expect leaks at the tank, since I didn’t use any sealant, as well as at the “short circuit” in the front.  Everywhere else should better be dry!


IMG 0008 2

Fuel Line & Return Line on bottom of Fuel Tank

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