My Wooden Airplane
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2/16/2013 - 2/28/2013

Fuel Tank, Part 3

Well, before running the fuel lines, I decided I needed to test my new fuel tank for leaks. Unfortunataly, it had plenty of them! It turns out, out of the nearly 600 rivets installed, six of them didn't get set properly, and when the shanks got pulled out, they were was pulled out at a slight angle, causing the "sealed" ends to crack open. I really didn't want to cut a hole (actually four) in my new tank in order to re-seal them from the inside, so I tried putting a blob of sealer on ALL of the rivets from the outside. I figured if that didn't work, then I'd have no choice but to open it up, but fortunately, it worked!

By the way, to test the tank for leaks, I found an idea on the Internet for using a water manometer. Plug all the tank openings and connect a long, clear plastic tube to one of them. Then take another tube and form it into the shape of a vertical "U". Each leg of the "U" should be about 4 feet tall. Then pour some water into the "U-shaped" tube so that both legs are filled up about half-way. Connect one of the legs of the "U" to the tube going to the tank, while leaving the top of the other leg open. (Make sure the tank is lower than the tops of the "U", or you might get water in the tank!) Use some compressed air to pressurize the tank so that the water in the tank side of the "U" is forced down about a foot (and the water in the open end of the "U" is forced up by the same amount). This "height differential" of about 24 inches is roughly equivalent to about 1 psi. You don't want to pressurize the tank any more than that! Then, all you have to do is watch the water levels. If they start to return to their original levels, then you have a leak! If they stay the same (or move further apart), then you're golden! Once I finally had my tank sealed, the levels actually moved further apart because the air inside the tank started to warm up. It's that sensitive!

Total Time: 3.0 hrs.