Pete=0Ayour explanation is correct. Thanks for expanding my criptic remarks
!=0AGraham=0A=0A=0A=0A=0A________________________________=0A From: Pete <pe
terz@zutrasoft.com>=0ATo: "europa-list@matronics.com" <europa-list@matronic
s.com> =0ASent: Friday, 7 June 2013, 16:55=0ASubject: Re: Europa-List: You'
ll Cry Pip Pins=0A =0A=0A=0AAll the lifting loads are taken by the lift pin
s on the side of the fuse. The pip pins function only to tie the spars toge
ther and keep the wings from folding up under G.=0A=0AThe geometry is such
that when the main spars are flexing under load, the pip pin locations on t
he spars move downward relative to the lift pins at the side of the fuse (a
s the lift pins are further out along the radius of the flexing spars), so
the net result is that the pip pins actually push DOWNWARDS on the seat bac
k under high positive G's.....totally counter productive. =C2-The seat ba
ck bushes should be clearance vertically IMHO to avoid this situation.=0A
=0AThe seat back bushes may however provide some (weak?) support in keeping
the pip pins from twisting out of the spars under their asymmetrical=C2-
twisting load. =C2-Many gliders use fork-spar arrangements to avoid this.
=0A=0ACheers,=0APete=0AA239=0A=0AOn Jun 7, 2013, at 9:45 AM, "William Danie
ll" <wdaniell.longport@gmail.com> wrote:=0A=0A=0AGraham=0A>=C2-=0A>I am v
ery interested by this statement .so as I understand it the spars
are the main load bearing structure in the airpcraft if the seat b
ack bush does not do the this what does?=C2- How does the motorglider wor
k?=0A>=C2-=0A>Will=0A>=C2-=0A>From:owner-europa-list-server@matronics.c
om [mailto:owner-europa-list-server@matronics.com] On Behalf Of GRAHAM SING
LETON=0A>Sent: Friday, June 07, 2013 04:42=0A>To: europa-list@matronics.com
=0A>Subject: Re: Europa-List: You'll Cry Pip Pins=0A>=C2-=0A>Frans=0A>The
pip pin on the port side is there to prevent the starboard spar from twist
ing away from the =0A>port spar under high load. The starboard side has no
need of retention because the overlapping =0A>spar provides that function.
=0A>Strictly speaking the bush in the seat back bulkhead is of no value, in
fact it increases the load on the spars.=0A>Be better without it as per th
e motor glider. (but DYOR)=0A>Graham=0A>=C2-=0A>=C2-=0A>=0A>___________
_____________________=0A>=0A>From:Frans Veldman <frans@privatepilots.nl>=0A
>To: europa-list@matronics.com =0A>Sent: Friday, 7 June 2013, 9:07=0A>Subje
ct: Re: Europa-List: You'll Cry Pip Pins=0A>=0A>--> Europa-List message pos
ted by: Frans Veldman <frans@privatepilots.nl>=0A>=0A>On 06/07/2013 09:40 A
M, Tony Renshaw wrote:=0A>=0A>>=C2- Talking about pip pins, does anyone s
ee any merit in using two of the Port pip pins, another for the Std spar to
o?=0A>=0A>If I recall correctly, there was some technical reason why both p
ip pins=0A>are different. I forgot the details, but this discussion has bee
n held=0A>before and someone with insight argued why using a pip pin on the
=0A>starboard side was not such a good idea. It had something to do with th
e=0A>different arrangement and thus different torsional loads on the=0A>sta
rboard side because the spars overlay "the other way around". The pin=0A>ha
d to be longer there to allow some movement, and because it needs to=0A>hav
e some play a pip pin can not be used (unless you make it longer than=0A>it
should be but then you need an additional retaining mechanism which=0A>of
course negates the whole idea of using a pip pin in the first place.)=0A>
=0A>Although I have modified my aircraft quite a lot, this is an area where
=0A>I am shy to deviate from the build plan, as it is one of the most=0A>cr
itical structural area's. As all of the other pins are pip pins my bet=0A>i
s that there must have been a reason why to use a different arrangement=0A>
on this specific pin. Surely it can't be because it was cheaper or so,=0A>o
r the designer was short of one pip pin and decided to wo==C2- --> http
://www.matronics.com/Navigator?Europa-List=0A>_ref="http://forums.matroni
cs.com/" target="_blank">http://forums.matronbsp; Thank you for your gene
rous nbsp; =C2- =C2- =C2- =C2- =C2- =C2- -Matt Dralle, List Adm
in.=0A>=0A>=0A>=0A>=0A>=0A>=C2-=0A>=C2-=0A>http://www.matronics.com/Nav
igator?Europa-List=0A><=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2-=C2
-=C2-=C2-- MATRONICS WEB FORUMS -=0A>http://forums.matronics.com=0A>h
ttp://www.matronics.com/contribution=0A>=C2-=0A>========
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