From: BOBPAS26@aol.com
Message-ID: <0.6ba6c2e4.25791659@aol.com>
Date: Fri, 3 Dec 1999 07:49:29 EST
Subject: Re: Fuel Tanks-Leak Checking
To: lancair.list@olsusa.com
Mime-Version: 1.0

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Marv,
We are currently building two Lancair IV-P's and have recently completed leak 
checking the wing tanks. Found no leaks in the tanks, but it was several 
days/tries before we determined this, as there are a surprising number of 
planned/intentional holes in the tanks that were not easy to secure to the 
level needed. (fuel filler, vent, feed, return, two water drains and fuel 
gauge probe--I think that's all the planned holes)

We plugged all holes but the wingtip vent, then inflated a heavy-duty balloon 
(the party balloons used for helium worked well for us) and secured it to the 
vent pipe with a piece of rubber band. It took several tries to secure all 
the planned holes--and we were initially very concerned. Two initial failures 
illustrate the problem: initially used grease to seal the fuel filler 
caps--not even close to good enough. Then used two pieces of overlapping 
release tape to cover the caps completely--better, but still got a small leak 
along the overlap joint. Think that was about the last problem; once we'd 
sealed that, the balloon test held for at least three days. Moral of the 
story for us was to be sure we'd securely plugged all the planned holes 
before presuming we had a more serious problem. 

By the way, we decided to do the test before installing the ailerons, flaps 
and other hardware, thinking any leak would be much easier to repair/get to. 
Having "perfected" the leak check method, intend to do it again after 
plumbing installation to be sure we have the rest of the system as tight. 
Hope this helps.

Bob Pastusek
N437RP

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