>
>I posted a letter about 3 months ago about the use of a teflon tubing around
>a reduced diameter stainless steel replacement hinge pin. I didnt get one
>expression of interest, even though it is a commonplace fix for hinge wear
>on Longeze and Vari-eze a/c in the States!
Interestingly, we are looking into this very subject. The main concern
is
the shear strength of the reduced diameter pin. Once stress analysis
has
been carried out to satisfy JAR/VLA we can make a decision.
> Whilst I discuss hinges I would like to expound on my theory of the poor
>safetying method of bending pins. Firstly, they don't bend easily as some of
>you already know. Secondly, I guarantee that the last lug you would have
>been applying lateral pressure on, to bend the hinge pin, is distorted.
The bend of the hinge pin is intended to start beyond the end of the
hinge, which I appreciate may be difficult.
Now I am not a metallurgist but I guarantee that the molecules of aluminium
have
>not been stretched, but torn.
I haven't yet, in my role as a build inspector for the PFA, found a
hinge
which has been so badly bent as to be torn. A hinge in this condition
would naturally be rejected.
He entrapped the hinge pin within the hinge and
>secured it from working out with 2 small split pins through the outboard
>lugs.
This is a neat method of securing hinge wire within the hinge. I doubt
that the margins are so close that an extended hinge would be required.
We'll look at this at the same time as the smaller diameter wire
as a
worst case.
Regards,
Andy Draper
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