Bill's RV-7 Project

November 6, 2006 - More Fuel Tank Leak Testing

November 6, 2006 - More Fuel Tank Leak Testing

I did the balloon test on the tanks and everything looked OK, so I started putting them back on the wings. The more I thought about it though, the more I figured I had better do the manometer test before I spent the time putting in all the screws and torqueing all the bolts.

I went down to the local hardware store and bought nine feet of 3/8" inner diameter clear tubing. I attached one end to the fuel vent tube and taped the other at the top of that red pole. Then I pored a little bit of water down the tube, being careful it didn't go up into the tank. I pumped air in the tank through the bicycle tube valve-stem thing until there was 5 1/4" difference between the level off the water on the left and right. The 5 1/4" represents 2.4 psi of air pressure in the tank.

If the water levels remain the same, there is no leak. Unfortunately, the levels gradually changed after a few minutes. I tried to find the leak by spraying soap water over the seems and rivets but had no luck. I guess I'll have to take the tank off and try the soap water technique.