On Sunday, Dec 30, 2007, at 11:33 US/Pacific, Steve Hagar wrote:
> I have tore into the top of the cockpit seatback to get at
> the gas tank to pull it out because of the crack. Once the top was off
> what
> was present was slightly disturbing. We have our extra support pads
> to
> keep the tank from pooching into our spar cavity and interfering with
> the
> aileron belcrank rod. Every interior surface looks like that. The
> top of
> the tank is vavy from expansion and the back surface exhibits the same
> condition. In all cases flat surfaces of the tank are stressed and
> buckled
> because of the expansion. You just don't see it unless you take the
> lid
> off.
Steve,
Thanks for sharing your frustrations w/ your fuel tank and passing on
your thoughts on the issue of cracking....sobering thoughts and pixs
indeed. A couple of questions:
- When you say "extra support pads", do you mean that you installed
some pads in addition to those called for?...If so, can you describe
them?
- At some point, I seem to recall that the supplied tanks were changed
in some way to eliminate or reduce expansion. When did you purchase
your original tank? Do you know if you have one of the earlier or later
versions of the tank?
- Do you attribute your tank's failure (in part) to any extreme
temperature conditions which it may have been exposed to in your part
of the world?
To Anyone: Would you be willing to share any protocols you follow which
you believe will guard against tank shrinkage and stress cracking?
> I made note to a motorhead friend of mine at work that my airplane had
> gotten a crack in its gas tank. He knows nothing of Europas or of
> homebuilt aircraft. He asked me if I had a rotomolded polyethelyne
> tank.
> I said yes. He asked me if I left the tank dry for awhile. Yes
> again. He
> noted to me that there is a kit car company out there that makes
> custom
> tanks as these for cars. The company specifically states that if you
> mount
> the tank by fiberglassing it in and let it dry out. It will crack and
> they
> assume no responsibility. You are supposed to buy their mounting kit
> and
> strap it in.
I got to confess that I questioned (to myself) the implications of
fibreglassing in a tank which is subject to expansion, but blithely
went ahead and installed it per plans, ignoring that little voice
saying, "Hey...this can't be good, there's got to be a better way!"
As for my previous post about my opinion of the high degree of
precision built into the kit, I made that as an architect and
homebuilder, not as a machinist, so the world of tight tolerances is
one in which I've had virtually no direct experience. I do marvel at
some of the various hardware assemblies and know that if left to my own
devices for fabrication the results would not be
satisfactory...sometimes the designs seem a bit too clever but that's a
story for another time.
> Also I also have a pair of reamers available 16 and 16.5 mm, one for
> the
> rough cut and one for the fine cut. I have cut them short and
> machined a
> hex on each end. That way you don't have to pull the endine way out
> and
> you can put a ratchet on the end to run them home.
That sounds excellent...thanks for your offer to make them available to
others!
Regards and good luck w/ getting your plane back in the air soon,
Fred
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