I have seen this third hinge argument on the list before and I was thinking
of installing extra hinges on mine. Does anyone know if this would be an
acceptable mod with the LAA in the UK?
Regards
Rick Sivier
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Sidsel & Svein
Johnsen
Sent: 02 August 2010 16:02
Subject: SV: Europa-List: Re: Teflon & Steel Pin Hinge: LAA Mod?
<sidsel.svein@oslo.online.no>
>>Basically he found that the teflon repair failed in a short time too.<<
Cannot argue with that, but I can at least put my own experience on the
balance: The Teflon repair on my hinges show no signs of any wear 60 hours
after I did the mod (more than the time it took for some of the original
hinges to develop slack).
>>So he reams the hinges to remove the burrs and replaces the pin with close
tolerance welding rod.<<
Sounds very risky to me. If the hinges (not the pins) have some wear, what
is the strength of the remaining material after reaming? Answer: Nobody
knows, probably.
Regardless of the repair method, I assume finding the cause of the wear must
be on top of the "to do" list. In my case, the outer hinge on each aileron
showed noticeable wear, but none of the other hinges. I suspected that a
contributing cause (in addition to maybe not perfectly lined up hinges??)
could have been that there was a fair length of the aileron span outside of
the outer hinge, i.e. unsupported and allowed to flex (noticeable "give" if
bending the aileron tip up or down even with tight hinges) and maybe
vibrating some? When I did the Teflon repair on both the slack hinges and
all the others, I also installed a third hinge at the outer end of each
aileron (also with the Teflon mod). This effectively stopped the "give" in
the aileron.
There is a drawback with the Teflon "repair": It does not remove the slack
developed in a worn hinge, although it may stop or delay further wear.
Therefore, it is best done before any wear has developed.
Note: In Norway, the CAA considers Experimental aircraft as "experimental",
meaning that we are allowed a fair degree of experimenting!
Svein
LN-SKJ
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