Graham
I am very interested by this statement ..so as I understand it the spars are
the main load bearing structure in the airpcraft. if the seat back bush does
not do the this what does? How does the motorglider work?
Will
From: owner-europa-list-server@matronics.com
[mailto:owner-europa-list-server@matronics.com] On Behalf Of GRAHAM
SINGLETON
Sent: Friday, June 07, 2013 04:42
Subject: Re: Europa-List: You'll Cry Pip Pins
Frans
The pip pin on the port side is there to prevent the starboard spar from
twisting away from the
port spar under high load. The starboard side has no need of retention
because the overlapping
spar provides that function.
Strictly speaking the bush in the seat back bulkhead is of no value, in fact
it increases the load on the spars.
Be better without it as per the motor glider. (but DYOR)
Graham
_____
From: Frans Veldman <frans@privatepilots.nl>
Sent: Friday, 7 June 2013, 9:07
Subject: Re: Europa-List: You'll Cry Pip Pins
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 wo= -->
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