Posted for Bryan Wullner <SBEJ@verizon.net>:

I am building a Lancair 360. The previous builder already closed out the
wings. He used the 1/4" lines to feed to the Header Tank as the manual
suggests. And He never installed the fuel probes.
Can anyone suggest a way for me to test for leaks in the wings?
What can I do to get a fuel level reading without cutting into my tanks to
install probes?

Thank You,
Bryan

[To pressure test your tanks, install and seal the fuel caps, attach a party balloon over each of the tank vents, then pressurize each tank through a hose attached to the tank outlet. Measure the diameters of the filled balloons and check them each hour or two over the next 24 hours... if a balloon deflates it's time to locate the leak in that tank. I'm sure there are other solutions that will be suggested, but this is a very workable down 'n' dirty method that protects you from over-pressurizing the tanks. The only complicating factor is if a major barometric pressure change moves through during the test... if a low moves in the balloons will swell, if a high moves in they'll shrink. Temperature differentials will have a similar effect, so try to keep the shop at a constant temperature to minimize it.

As for mains fuel levels, if you're dead set against installing probes or level sensors you'll need to track your fuel tranfers to the header tank. First step is to measure and note the flow rate in gallons per minute from your tansfer pumps. Before each flight you simply stick your tanks (ie, using a calibrated dipstick marked in gallons), note each tank's starting level and then time all transfers. Do the math to determine how much fuel is transferred and keep the running totals on your knee board. (Worked great for Lindbergh.) The manual also recommends that you use clear fuel lines from the transfer pumps to the header and provide a place for them to be viewed during the transfer process. When you've run a main dry you'll see air bubbles in its respective header feed line.

<Marv> ]