Hi! Frans/all.
I used two spar pip pins from the outset since it needs remembering by a
novice helper as to which side is which. But my suggestion is that the last
thing I would wish is for one spar to migrate off the end of the pin . This
whole concept was protected somewhat by the installation of the "cuff"
encompassing both spars which came later in the development. Perhaps Neville
will elucidate somewhat, since he does helpfully monitor this forum? It is
my opinion that the original Europa team did decide to go for the cheap
option. Any end play on the pip pins has been taken up by stacking washers
under the heads of the pins when first installing the seat back bushings.
However it is critical to ensure that the pip pins have got right "home" to
allow their safety balls to expand.
-----Original Message-----
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of Frans Veldman
Sent: 07 June 2013 09:07
Subject: Re: Europa-List: You'll Cry Pip Pins
--> <frans@privatepilots.nl>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
> Talking about pip pins, does anyone see any merit in using two of the
Port pip pins, another for the Std spar too?
If I recall correctly, there was some technical reason why both pip pins are
different. I forgot the details, but this discussion has been held before
and someone with insight argued why using a pip pin on the starboard side
was not such a good idea. It had something to do with the different
arrangement and thus different torsional loads on the starboard side because
the spars overlay "the other way around". The pin had to be longer there to
allow some movement, and because it needs to have some play a pip pin can
not be used (unless you make it longer than it should be but then you need
an additional retaining mechanism which of course negates the whole idea of
using a pip pin in the first place.)
Although I have modified my aircraft quite a lot, this is an area where I am
shy to deviate from the build plan, as it is one of the most critical
structural area's. As all of the other pins are pip pins my bet is that
there must have been a reason why to use a different arrangement on this
specific pin. Surely it can't be because it was cheaper or so, or the
designer was short of one pip pin and decided to work around it...
Regards,
Frans
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