Gas Tank

9/28/2008

I ended up focusing on the gas tank in the middle of playing with instrument panels due to having to dry fit the tank to confirm clearance for the passenger alti [there is only 3" of depth]. One thing lead to another, so I started to tackle the fuel gauge problem.

I didn't want a sight gauge which is great - if you are sat in the front hole... a float type sender unit would clash with the flop tube in the tank, so after bending the ears of a few guys, and some from the forum, I decided to use a capacitance sender. This is basically a probe/tube inserted into the tank, and the E and F levels are electronically calibrated to a matching gauge in the panel. The first inch of the probe is bendable to a mx 1" radius, so I could tweak the probe into a location where the flop tube misses it. I needed a plate welding to the tank to accommodate the sender unit, something I didn't dare tackle myself. So I got one of my TIG gurus I know to do the honors. Prior to paint, I pressure tested the tank with a $5 test kit from Vansaircraft.com, there was a leak, and for the life of me I couldn't find it with soap bubbles. Finally, I replaced the rubber gasket in the filler cap. Viola. Once sprayed with Randolph epoxy primer, the sender was fitted. I had no sealer, so I went a few doors down to an A&P buddy who loaned me some nasty black stuff for the job.

Now here comes screw-up time...of all the places I could have positioned the sender, I had to put it where it would clash with the rear tank retaining strap didn't I? See pic. I am still thinking of how to fix this. The pic shows one approach: discard the X section, fab' a piece that sits over the sender [circular? less material?] and weld on with saddle straps. The other idea would be to move the strap to the rear, trouble is, this tank is 30 gallons (tight), so I am concerned that welding on new bushings on the longerons will clash during removal and insertion of the tank.

I have an old gas isolation valve, I polished up the brass with a dremel and sprayed with a clear lacquer. I also sprayed the red lever with Krylon rattle red, then Epoxy Clear Coated the lever for longevity. I also made a facia plate for the valve and have labeled it with a fancy on/off graphic using the a Decal Pro kit.

So, looking ahead, I need to fix the tank strap, assemble the panels, then I'll probably be looking at fuel line placements for the main and upper tank.