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ACRO E-mail Archive Thread: [Acro] Re: PITTS S1 FUEL TANK PROBLEM

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ACRO E-mail Archive Thread: [Acro] Re: PITTS S1 FUEL TANK PROBLEM



                


Thread: [Acro] Re: PITTS S1 FUEL TANK PROBLEM

Message: [Acro] Re: PITTS S1 FUEL TANK PROBLEM

Follow-Up To: ACRO Email list (for List Members only)

From: "John Harlan" <jmharlan at ev1.net>

Date: Tue, 19 Mar 2002 01:14:39 UTC


Message:

  Hi Glen-
I had two cracks on the back surface of my Aviat tank in an S1E.  I tried an
aluminum doubler bonded on with PRC, however I didn't stop drill the cracks.
This worked for about 150 hours but eventually the crack continued out from
under the doubler.  Stop drilling would certainly extend the life of the
repair.

When I removed the tank, I also found two more cracks just starting on the
front side.

The Pitts plans call out 1100-O aluminum.  I don't know if Aviat still uses
this, but based on the failure history, I suspect so.  A better material to
use is 5052 condition H32.  This material has better fatigue life under a
similar stress environment because it has about double the yield strength,
and it is also a fatigue resistant alloy.  Most others (all that I know of)
making aluminum tanks use 5052.  You can get experimental fuel tanks for
your Pitts made from 5052 from two or three different sources.  It might be
possible to get a field approval for a certified airplane - don't know.

I've suggested to Ed S. at Aviat that they consider a material change.  I
didn't get a reply.  Anybody know if he still works there?

When I was shopping for a tank, I did an unscientific poll - it turned up 7
reports of failures on 1100 tanks, none on 5052 tanks.  Anecdotal, I
know....

John
S1E (on second tank - this time 5052)
Austin


----- Original Message -----
From: <Gandrmarsh at aol.com>
To: <acro at gf24.de>
Sent: Monday, March 18, 2002 6:52 AM
Subject: [Acro] PITTS S1 FUEL TANK PROBLEUM


>
>
>   I have a fuel tank that cracked on the front pannel of the tank. This
will
> be the 3rd tank in appx. 800 hours. The first one oil caned on the aft
side.
> I tried to weld it but it oxadized and became brittle and re cracked, so I
> replaced it to a new one from Pitts. A good friend of mine had a S1T and
the
> same thing happened to him. This time it oil caned up front. So this is my
> second tank. This makes 3 tanks between 2 of us in less than 800 hours. Am
I
> missing something here? I believe there was a post about S1 fuel tanks a
> while back that I missed. Can any one help me on what to do? Does anyone
make
> a tank that doesn't crack? Or do I go back to the factory? We have over 10
> S1's in our chapter so this information would be helpful.
>
>                                 Glen Marshman Chapter 12 Prez
>
>



                


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