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tonyrenshaw268(at)gmail.c
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 Posted: Thu Jun 06, 2013 11:40 pm Post subject: You'll Cry Pip Pins |
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Hi Fred and co,
Isn't the width of the spars and seat back the depth of the shank of the pip pin?
Don't have it with me to measure.
Talking about pip pins, does anyone see any merit in using two of the Port pip pins, another for the Std spar too?
Regards
Tony Renshaw
Sent from my iPad
On 07/06/2013, at 4:01 PM, Europa-List Digest Server <europa-list(at)matronics.com> wrote:
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davidjoyce(at)doctors.org
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| Posted: Thu Jun 06, 2013 11:57 pm Post subject: You'll Cry Pip Pins |
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Tony, I opted to have 2 pippinned spar pins on the logic
that it confines the ends of the spars both sides and
almost certainly improves the strength of he combination,
which tend to twist and depart from the straight and
narrow under high load. It also looks neater! Regards,
David Joyce, GXSDJ
On Fri, 7 Jun 2013 16:40:13 +0900
Tony Renshaw <tonyrenshaw268(at)gmail.com> wrote:
| Quote: |
<tonyrenshaw268(at)gmail.com>
Hi Fred and co,
Isn't the width of the spars and seat back the depth of
the shank of the pip pin?
Don't have it with me to measure.
Talking about pip pins, does anyone see any merit in
using two of the Port pip pins, another for the Std spar
too?
Regards
Tony Renshaw
Sent from my iPad
On 07/06/2013, at 4:01 PM, Europa-List Digest Server
<europa-list(at)matronics.com> wrote:
> 1 _____________________________________
>
Un/Subscription,
Forums!
Admin.
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frans(at)privatepilots.nl
Guest
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| Posted: Fri Jun 07, 2013 12:07 am Post subject: You'll Cry Pip Pins |
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On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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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grahamsingleton(at)btinte
Guest
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| Posted: Fri Jun 07, 2013 1:42 am Post subject: You'll Cry Pip Pins |
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|
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(at)privatepilots.nl>
To: europa-list(at)matronics.com
Sent: Friday, 7 June 2013, 9:07
Subject: Re: You'll Cry Pip Pins
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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= --> http://www.matronics.com/Navigator?Europa-List
_ref="http://forums.matronics.com/" target="_blank">http://forums.matronbsp; Thank you for your generous nbsp; -Matt Dralle, List Admin.<b======
| | - The Matronics Europa-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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ptag.dev(at)talktalk.net
Guest
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| Posted: Fri Jun 07, 2013 1:56 am Post subject: You'll Cry Pip Pins |
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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.
--
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wdaniell.longport(at)gmai
Guest
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| Posted: Fri Jun 07, 2013 5:45 am Post subject: You'll Cry Pip Pins |
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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(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 04:42
To: europa-list(at)matronics.com
Subject: Re: 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(at)privatepilots.nl (frans(at)privatepilots.nl)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 9:07
Subject: Re: You'll Cry Pip Pins
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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= --> http://www.matronics.com/Navigator?Europa-List
_ref="http://forums.matronics.com/" target="_blank">http://forums.matronbsp; Thank you for your generous nbsp; -Matt Dralle, List Admin.
| Quote: | | http://www.matronics.com/Navigator?Europa-List< - MATRONICS WEB FORUMS - |
01234567
[quote][b]
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peterz(at)zutrasoft.com
Guest
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| Posted: Fri Jun 07, 2013 7:57 am Post subject: You'll Cry Pip Pins |
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|
All the lifting loads are taken by the lift pins on the side of the fuse. The pip pins function only to tie the spars together and keep the wings from folding up under G.
The geometry is such that when the main spars are flexing under load, the pip pin locations on the spars move downward relative to the lift pins at the side of the fuse (as 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 back under high positive G's.....totally counter productive. The seat back bushes should be clearance vertically IMHO to avoid this situation.
The seat back bushes may however provide some (weak?) support in keeping the pip pins from twisting out of the spars under their asymmetrical twisting load. Many gliders use fork-spar arrangements to avoid this.
Cheers,
Pete
A239
On Jun 7, 2013, at 9:45 AM, "William Daniell" <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)> wrote:
[quote]v\:* {behavior:url(#default#VML);} o\:* {behavior:url(#default#VML);} w\:* {behavior:url(#default#VML);} .shape {behavior:url(#default#VML);} <![endif]--> <![endif]--> <![endif]-->
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(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 04:42
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: 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(at)privatepilots.nl (frans(at)privatepilots.nl)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 9:07
Subject: Re: You'll Cry Pip Pins
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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= --> http://www.matronics.com/Navigator?Europa-List
_ref="http://forums.matronics.com/" target="_blank">http://forums.matronbsp; Thank you for your generous nbsp; -Matt Dralle, List Admin.
01234567
8
[b]
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grahamsingleton(at)btinte
Guest
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| Posted: Fri Jun 07, 2013 9:02 am Post subject: You'll Cry Pip Pins |
|
|
Pete
your explanation is correct. Thanks for expanding my criptic remarks!
Graham
From: Pete <peterz(at)zutrasoft.com>
To: "europa-list(at)matronics.com" <europa-list(at)matronics.com>
Sent: Friday, 7 June 2013, 16:55
Subject: Re: You'll Cry Pip Pins
All the lifting loads are taken by the lift pins on the side of the fuse. The pip pins function only to tie the spars together and keep the wings from folding up under G.
The geometry is such that when the main spars are flexing under load, the pip pin locations on the spars move downward relative to the lift pins at the side of the fuse (as 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 back under high positive G's.....totally counter productive. The seat back bushes should be clearance vertically IMHO to avoid this situation.
The seat back bushes may however provide some (weak?) support in keeping the pip pins from twisting out of the spars under their asymmetrical twisting load. Many gliders use fork-spar arrangements to avoid this.
Cheers,
Pete
A239
On Jun 7, 2013, at 9:45 AM, "William Daniell" <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)> wrote:
| Quote: | 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(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 04:42
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: 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(at)privatepilots.nl (frans(at)privatepilots.nl)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 9:07
Subject: Re: You'll Cry Pip Pins
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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= --> http://www.matronics.com/Navigator?Europa-List
_ref="http://forums.matronics.com/" target="_blank">http://forums.matronbsp; Thank you for your generous nbsp; -Matt Dralle, List Admin.
01234567
8
|
9
[quote][b]
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wdaniell.longport(at)gmai
Guest
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| Posted: Fri Jun 07, 2013 9:06 am Post subject: You'll Cry Pip Pins |
|
|
Well I damned, I’d never have thought that. Those thick spars look like they should be supporting the aircraft but the weedy looking fuze pins are actually do all the (lifting) work.  So the spars’ main job is to prevent the wings folding forward or back?
So the really important thing is to keep the spars together not tie the spars into the fuze?
I am woefully ignorant.
Will
From: Pete [mailto:peterz(at)zutrasoft.com]
Sent: Friday, June 07, 2013 10:56
To: europa-list(at)matronics.com
Cc: wdaniell.longport(at)gmail.com
Subject: Re: You'll Cry Pip Pins
All the lifting loads are taken by the lift pins on the side of the fuse. The pip pins function only to tie the spars together and keep the wings from folding up under G.
The geometry is such that when the main spars are flexing under load, the pip pin locations on the spars move downward relative to the lift pins at the side of the fuse (as 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 back under high positive G's.....totally counter productive. The seat back bushes should be clearance vertically IMHO to avoid this situation.
The seat back bushes may however provide some (weak?) support in keeping the pip pins from twisting out of the spars under their asymmetrical twisting load. Many gliders use fork-spar arrangements to avoid this.
Cheers,
Pete
A239
On Jun 7, 2013, at 9:45 AM, "William Daniell" <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)> wrote:
[quote]
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(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 04:42
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: 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(at)privatepilots.nl (frans(at)privatepilots.nl)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 9:07
Subject: Re: You'll Cry Pip Pins
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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= --> http://www.matronics.com/Navigator?Europa-List
_ref="http://forums.matronics.com/" target="_blank">http://forums.matronbsp; Thank you for your generous nbsp; -Matt Dralle, List Admin.
012345678901234
[b]
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grahamsingleton(at)btinte
Guest
|
| Posted: Fri Jun 07, 2013 12:15 pm Post subject: You'll Cry Pip Pins |
|
|
William
just a bit more ignorant than me! The wing spars stop the wings folding up, (or down), the rear lift pins take the weight of the fuselage
into the wings and stop them folding forwards at high G loading, (that's none intuitive isn't it?) the front pins carry the resat of the fuse weight into the wings.
The spars don't need to be tied the the fuselage.
Graham
From: William Daniell <wdaniell.longport(at)gmail.com>
To: 'Pete' <peterz(at)zutrasoft.com>; europa-list(at)matronics.com
Sent: Friday, 7 June 2013, 18:05
Subject: RE: You'll Cry Pip Pins
Well I damned, I’d never have thought that. Those thick spars look like they should be supporting the aircraft but the weedy looking fuze pins are actually do all the (lifting) work. So the spars’ main job is to prevent the wings folding forward or back?
So the really important thing is to keep the spars together not tie the spars into the fuze?
I am woefully ignorant.
Will
From: Pete [mailto:peterz(at)zutrasoft.com]
Sent: Friday, June 07, 2013 10:56
To: europa-list(at)matronics.com
Cc: wdaniell.longport(at)gmail.com
Subject: Re: You'll Cry Pip Pins
All the lifting loads are taken by the lift pins on the side of the fuse. The pip pins function only to tie the spars together and keep the wings from folding up under G.
The geometry is such that when the main spars are flexing under load, the pip pin locations on the spars move downward relative to the lift pins at the side of the fuse (as 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 back under high positive G's.....totally counter productive. The seat back bushes should be clearance vertically IMHO to avoid this situation.
The seat back bushes may however provide some (weak?) support in keeping the pip pins from twisting out of the spars under their asymmetrical twisting load. Many gliders use fork-spar arrangements to avoid this.
Cheers,
Pete
A239
On Jun 7, 2013, at 9:45 AM, "William Daniell" <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)> wrote:
| Quote: | 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(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 04:42
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: 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(at)privatepilots.nl (frans(at)privatepilots.nl)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 9:07
Subject: Re: You'll Cry Pip Pins
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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= --> http://www.matronics.com/Navigator?Europa-List
_ref="http://forums.matronics.com/" target="_blank">http://forums.matronbsp; Thank you for your generous nbsp; -Matt Dralle, List Admin.
012345678901234
http://www.matronics.com/Navigator?Europa-List |
5
[quote][b]
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wdaniell.longport(at)gmai
Guest
|
| Posted: Fri Jun 07, 2013 12:48 pm Post subject: You'll Cry Pip Pins |
|
|
Well i damned again and you’re right it’s not in the least intuitive. It’s fascinating!
Did I understand that tie bar between the rear lift pins in the XS is not present in the classic? If so the these folding forward forces are merely supported by the fuselage sides.
Thanks
Will
From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 15:15
To: europa-list(at)matronics.com
Subject: Re: You'll Cry Pip Pins
William
just a bit more ignorant than me! The wing spars stop the wings folding up, (or down), the rear lift pins take the weight of the fuselage
into the wings and stop them folding forwards at high G loading, (that's none intuitive isn't it?) the front pins carry the resat of the fuse weight into the wings.
The spars don't need to be tied the the fuselage.
Graham
From: William Daniell <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)>
To: 'Pete' <peterz(at)zutrasoft.com (peterz(at)zutrasoft.com)>; europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 18:05
Subject: RE: You'll Cry Pip Pins
Well I damned, I’d never have thought that. Those thick spars look like they should be supporting the aircraft but the weedy looking fuze pins are actually do all the (lifting) work. So the spars’ main job is to prevent the wings folding forward or back?
So the really important thing is to keep the spars together not tie the spars into the fuze?
I am woefully ignorant.
Will
From: Pete [mailto:peterz(at)zutrasoft.com (peterz(at)zutrasoft.com)]
Sent: Friday, June 07, 2013 10:56
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Cc: wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)
Subject: Re: You'll Cry Pip Pins
All the lifting loads are taken by the lift pins on the side of the fuse. The pip pins function only to tie the spars together and keep the wings from folding up under G.
The geometry is such that when the main spars are flexing under load, the pip pin locations on the spars move downward relative to the lift pins at the side of the fuse (as 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 back under high positive G's.....totally counter productive. The seat back bushes should be clearance vertically IMHO to avoid this situation.
The seat back bushes may however provide some (weak?) support in keeping the pip pins from twisting out of the spars under their asymmetrical twisting load. Many gliders use fork-spar arrangements to avoid this.
Cheers,
Pete
A239
On Jun 7, 2013, at 9:45 AM, "William Daniell" <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)> wrote:
| Quote: |
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(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 04:42
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: 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(at)privatepilots.nl (frans(at)privatepilots.nl)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 9:07
Subject: Re: You'll Cry Pip Pins
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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= --> http://www.matronics.com/Navigator?Europa-List
_ref="http://forums.matronics.com/" target="_blank">http://forums.matronbsp; Thank you for your generous nbsp; -Matt Dralle, List Admin.
0123
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[quote][b]
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grahamsingleton(at)btinte
Guest
|
| Posted: Fri Jun 07, 2013 2:13 pm Post subject: You'll Cry Pip Pins |
|
|
Yes,
Graham
no comment!
From: William Daniell <wdaniell.longport(at)gmail.com>
To: europa-list(at)matronics.com
Sent: Friday, 7 June 2013, 21:48
Subject: RE: You'll Cry Pip Pins
Well i damned again and you’re right it’s not in the least intuitive. It’s fascinating!
Did I understand that tie bar between the rear lift pins in the XS is not present in the classic? If so the these folding forward forces are merely supported by the fuselage sides.
Thanks
Will
From: owner-europa-list-server(at)matronics.com [mailto:owner-europa-list-server(at)matronics.com] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 15:15
To: europa-list(at)matronics.com
Subject: Re: You'll Cry Pip Pins
William
just a bit more ignorant than me! The wing spars stop the wings folding up, (or down), the rear lift pins take the weight of the fuselage
into the wings and stop them folding forwards at high G loading, (that's none intuitive isn't it?) the front pins carry the resat of the fuse weight into the wings.
The spars don't need to be tied the the fuselage.
Graham
From: William Daniell <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)>
To: 'Pete' <peterz(at)zutrasoft.com (peterz(at)zutrasoft.com)>; europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 18:05
Subject: RE: You'll Cry Pip Pins
Well I damned, I’d never have thought that. Those thick spars look like they should be supporting the aircraft but the weedy looking fuze pins are actually do all the (lifting) work. So the spars’ main job is to prevent the wings folding forward or back?
So the really important thing is to keep the spars together not tie the spars into the fuze?
I am woefully ignorant.
Will
From: Pete [mailto:peterz(at)zutrasoft.com (peterz(at)zutrasoft.com)]
Sent: Friday, June 07, 2013 10:56
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Cc: wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)
Subject: Re: You'll Cry Pip Pins
All the lifting loads are taken by the lift pins on the side of the fuse. The pip pins function only to tie the spars together and keep the wings from folding up under G.
The geometry is such that when the main spars are flexing under load, the pip pin locations on the spars move downward relative to the lift pins at the side of the fuse (as 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 back under high positive G's.....totally counter productive. The seat back bushes should be clearance vertically IMHO to avoid this situation.
The seat back bushes may however provide some (weak?) support in keeping the pip pins from twisting out of the spars under their asymmetrical twisting load. Many gliders use fork-spar arrangements to avoid this.
Cheers,
Pete
A239
On Jun 7, 2013, at 9:45 AM, "William Daniell" <wdaniell.longport(at)gmail.com (wdaniell.longport(at)gmail.com)> wrote:
| Quote: | 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(at)matronics.com (owner-europa-list-server(at)matronics.com) [mailto:owner-europa-list-server(at)matronics.com (owner-europa-list-server(at)matronics.com)] On Behalf Of GRAHAM SINGLETON
Sent: Friday, June 07, 2013 04:42
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Subject: Re: 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(at)privatepilots.nl (frans(at)privatepilots.nl)>
To: europa-list(at)matronics.com (europa-list(at)matronics.com)
Sent: Friday, 7 June 2013, 9:07
Subject: Re: Europa-List: You'll Cry Pip Pins
--> Europa-List message posted by: Frans Veldman <frans(at)privatepilots.nl (frans(at)privatepilots.nl)>
On 06/07/2013 09:40 AM, Tony Renshaw wrote:
| Quote: | 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= --> http://www.matronics.com/Navigator?Europa-List
_ref="http://forums.matronics.com/" target="_blank">http://forums.matronbsp; Thank you for your generous nbsp; -Matt Dralle, List Admin.
0123
|
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2 | Quote: | | < - MATRONICS WEB FORUMS - |
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| Quote: | | < - MATRONICS WEB FORUMS - |
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[quote][b]
| | - The Matronics Europa-List Email Forum - | | | Use the List Feature Navigator to browse the many List utilities available such as the Email Subscriptions page, Archive Search & Download, 7-Day Browse, Chat, FAQ, Photoshare, and much more:
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