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SV: SV: SV: SV: Re: wing lift/drag pins

 
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sidsel.svein(at)oslo.onli
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PostPosted: Tue Jul 02, 2013 4:48 am    Post subject: SV: SV: SV: SV: Re: wing lift/drag pins Reply with quote
Frans,

Quote:
But for me, as this was the topic of the original discussion, the question is:
what kind of forces do the wings pose on the fuselage?

As the fuselage doesn't want to go forward without the wings, but still goes
forward with the wings, it looks to me that it is possible that the wings
somehow pull the fuselage forward.

When you fly with the engine pulling on the fuselage (cannot pull on the wings in the Europa!), the fuselage pulls the wings.


When you glide, I don't know which part (fuselage or wings) have the best weight/drag ratio, so I don't know whether the fuselage wants to leave the wings behind or vice versa (I do suspect, though, that the wings are holding back the fuselage).

At unusual attitude or high G-loading, it has been stated on this forum that wings (on other airplanes) have moved forward when they broke off. This means that there has been a forward (centerline direction) net force acting from the wings onto the fuselage at that time, in addition to a perpendicular (to centerline) component, of course.


Quote:
And of course I have some clues as why the airplane (as a whole) actually
flies and I agree with your drawings, but again, the topic was:
the rear wing sockets, do they push or do they pull?

To really answer this question you should drawn the vector diagrams not for
the airplane as a whole, but for each of the components that make up the
airplane. And then it would be interesting to see what resultant force is
acting on the rear wing sockets.

Except in very uncommon circumstances, the rear wing pins on Europa are pushing backwards on the fuselage-mounted sockets, and tries to bend in the fuselage sides/compress the cross tie bar between the left and the right side sockets, as the wings have a resultant force going back and up during normal powered flight. Whether the resultant force can ever be directed forward of the perpendicular to the centerline in the Europa, I have no idea – but I will keep the pins in, just in case!


Quote:

Has anyone actually ever tried to fly without the rear pip pins in? If so, what
happened? If not, what would happen? Could you get away with it, or will
the wings fold forward during the landing flare?
I don't think the forces are too large anyway, as the original Europa design
didn't have the interconnecting bar between the sockets, and the original
structure is not really that strong with respect to pulling and pushing forces.

Frans, please promise that you will not be the first one to try that!!


/////////

I prefer to end my limited contribution to this tread now, but look very much forward to picking it up again over a cold beer at the Vichy fly-in. Perhaps also the beer’s force may be determined by which way we are leaning ……?

Regards,
Svein
[quote][b]

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grahamsingleton(at)btinte
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PostPosted: Tue Jul 02, 2013 6:11 am    Post subject: SV: SV: SV: SV: Re: wing lift/drag pins Reply with quote
Frans
I hope so too, you are a valued member on this forum!
There was one tragic incident with a Europa Classic, one of the rear lift pins pulled out of the threaded plate in the wing. There were doubts re original construction but nevertheless forward force must have been considerable.
Graham

From: Sidsel & Svein Johnsen <sidsel.svein(at)oslo.online.no>
To: europa-list(at)matronics.com
Sent: Tuesday, 2 July 2013, 13:48
Subject: SV: SV: SV: SV: Re: wing lift/drag pins


Frans,


Quote:
I don't think the forces are too large anyway, as the original Europa design
didn't have the interconnecting bar between the sockets, and the original
structure is not really that strong with respect to pulling and pushing forces.

Frans, please promise that you will not be the first one to try that!!


/////////

I prefer to end my limited contribution to this tread now, but look very much forward to picking it up again over a cold beer at the Vichy fly-in.  Perhaps also the beer’s force may be determined by which way we are leaning ……?

Regards,
Svein

Quote:







[quote][b]

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davidjoyce(at)doctors.org
Guest
PostPosted: Tue Jul 02, 2013 7:35 am    Post subject: SV: SV: SV: SV: Re: wing lift/drag pins Reply with quote
Graham & Frans, There were more than doubts - the three
alloy plates bonded into the wing root for the lift pin to
be screwed into were so misplaced that the drilled hole
overlapped the edge of one, just reached the edge of
another and was only just missing the third, so seriously
reducing the planned strength of the arrangement. It was
never established definitely but it was thought likely
that the dis -engagement of one tail plane led to a sudden
nose up and o0verstress of the wing structure.
Regards, David Joyce, G-XSDJ
On Tue, 2 Jul 2013 15:11:36 +0100 (BST)
GRAHAM SINGLETON <grahamsingleton(at)btinternet.com> wrote:
Quote:


Frans
I hope so too, you are a valued member on this forum!
There was one tragic incident with a Europa Classic, one
of the rear lift pins pulled out of the threaded plate in
the wing. There were doubts re original construction but
nevertheless forward force must have been considerable.
Graham


________________________________
From: Sidsel & Svein Johnsen
<sidsel.svein(at)oslo.online.no>
To: europa-list(at)matronics.com
Sent: Tuesday, 2 July 2013, 13:48
Subject: SV: SV: SV: SV: Re: wing lift/drag
pins



Frans,
 

> I don't think the forces are too large anyway, as the
>original Europa design
> didn't have the interconnecting bar between the sockets,
>and the original
> structure is not really that strong with respect to
>pulling and pushing forces.
>
Frans, please promise that you will not be the first one
to try that!!
 
/////////
 
I prefer to end my limited contribution to this tread
now, but look very much forward to picking it up again
over a cold beer at the Vichy fly-in.  Perhaps also the
beer’s force may be determined by which way we are
leaning ……?
 
Regards,
Svein


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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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