Greg,
Thanks for the info. What you say makes sense and I appreciate you taking
the time to help me out.
I put 60 ltrs in the tank today and shall leave things alone for a while to
see if we get any improvement.
I will report results .
Mike
(my tank was supplied in Jul. 99)
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Greg Fuchs
Sent: 03 April 2015 09:11
Subject: RE: Europa-List: Fuel Tank moved!!
Mike,
IMHO, It would be good to understand how the clearance issue happened,
before committing a solution..or even whether you need one. Determining
whether it was tank shrinkage rather than slippage might be the first
agenda.
When I tested my tank for holes, it was filled to at least 3/4 of a tank
full of fuel for about 6 months.
The tank changed shape over time, as noticed by the back side bulging out.
Thus, the fuel was left in it until about a day before installation,
thinking that it was best to anchor it to the aircraft in its normal
operating state which could eliminate some strain from the fiberglass plies
tugging at it. I did have to heat up and straighten out the back side of the
tank though, or it would not fit properly into its position. A heat gun,
some flat pieces of ply, and some weights were employed for that job.
The fiber-glassing went well, and the clearances were fine upon assembly.
Its been many years, so I am struggling to remember the time frame, but
sometime in the months that followed with the tank dry of fuel, the tank
reduced in size (shrank). I could tell, because in some areas it no longer
touched the plies used to strap it in. I did not quantify with
measurements..just used visual observation. Clearance was as much as 1/4" or
so in some areas. Then I noticed the top side of the rubber hose at the tank
outlet(s) brushing up against the torque tube. Not aggressively, just
lightly. It doesn't concern me much. As soon as I put fuel in, it should
resume the shape it had when I strapped it in. I did put in a plastic
rubbing strip to protect the paint finish on the torque tube.
I couldn't see any other way the outlet could be rubbing on the torque tube,
other than it must be that it expanded when fueled and shrunk once again
when the fuel was drained out (completely dry). Some day, the tank will be
re-fueled, and I can see what happens for sure with this clearance. Some
day, when the plane is close to being ready to fly, that is..
This may not describe your issue, but then again it might. Three months in
your garage should be long enough for it to shrink. How completely did you
empty your tank? I figure (guessing) the tank would take awhile to shrink,
so it certainly would not happen in flight. Weeks to months probably. It
would likely need to be mostly drained of fuel, to eliminate fuel vapor,
which might arrest the tank from shrinking. I am completely guessing here of
course, since I have not done these tests..
Tank treatment? ..My tank was shipped in late 2002. It 'should' have been
treated with fluoride by then (crossing fingers).
Greg
_____
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Mike Gamble
Sent: Thursday, April 02, 2015 10:12 AM
Subject: RE: Europa-List: Fuel Tank moved!!
Thanks for your input Greg.
I had drained the tank which very possibly moved it up a bit but I would not
like to think of this happening in flight.
Did you measure the clearance from your torque tube with and without fuel?
How on earth can I increase this clearance?
The manual just gives a suggested 2cm distance tank to floor.
Maybe this will generate some more response from the forum.
Mike
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