Today's Message Index:
----------------------
1. 02:10 AM - Re: wing lift/drag pins (Alan Carter)
2. 03:58 AM - Re: SV: SV: SV: Re: wing lift/drag pins (Frans Veldman)
3. 05:21 AM - Re: SV: Re: wing lift/drag pins (GRAHAM SINGLETON)
4. 05:48 AM - SV: SV: SV: SV: Re: wing lift/drag pins (Sidsel & Svein Johnsen)
5. 06:55 AM - Re: SV: Re: wing lift/drag pins (Pete)
6. 07:00 AM - Re: SV: Re: wing lift/drag pins (GRAHAM SINGLETON)
7. 07:11 AM - Re: SV: SV: SV: SV: Re: wing lift/drag pins (GRAHAM SINGLETON)
8. 08:35 AM - Re: SV: SV: SV: SV: Re: wing lift/drag pins (David Joyce)
9. 09:45 AM - Where did I go wrong? OFF TOPIC ()
10. 03:36 PM - Re: wing lift/drag pins (Alan Carter)
Message 1
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| Subject: | Re: wing lift/drag pins |
Ron.
Just read your friends replay,
There was an light certified aeroplane , many years ago,
Not sure who made it, maybe Pipe but i think it was Italian company ? but it had
forward swept wings.
Can, t spell it nether, a Metersocall
The Europa has a slim straight wing with a little wash out towards the tips. and
made of Glass fibre over foam formers, thats a close as i can get it.
Alan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=403776#403776
Message 2
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| Subject: | Re: wing lift/drag pins |
On 07/01/2013 07:49 PM, Sidsel & Svein Johnsen wrote:
> Do this, Frans: Shake off all your conceptions. Look ONLY at my
> illustrations. The global airplane forces are actually this simple.
I think we are both right, but each of us looking at a different
situation. You are talking about the airplane as a whole.
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.
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.
Mind you, I might be totally wrong on my idea. But I have a feeling that
it is beyond just our reasoning to really have a grasp which forces are
acting where on the individual interconnecting components. As I recall,
the "cuff" around the two wingspars was a "fix" for some unforeseen
force acting on the wing spars causing them to twist somehow around each
other. Despite the great souls working on the original design of the
wings, it was not foreseen that the cuffs would be necessary.
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
Message 3
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| Subject: | Re: wing lift/drag pins |
Svein=0AI admire your patience and courtesy,=C2- the persistent deniers o
n this tread have =0Ajust about exhausted mine! First of all one should sta
rt with the facts; when a wing =0Afails due to high positive load it claps
forwards. Saying "I don't believe it because it =0Adoesn't fit my understan
ding or theory might be described as "an academic reaction to an inconvenie
nt truth"=0AThis "forward lift component" is very counter intuitive, the on
ly way to approach it is to =0Arefer to a diagram like yours. The criterion
a lot of people overlook is that lift is=0Aperpendicular to line of flight
, which is NOT parallel with the centre line of the fuselage.=0ANor is it 1
80deg from the line of gravity.=0AGraham=0A=0A=0A=0A=0A____________________
____________=0A From: Sidsel & Svein Johnsen <sidsel.svein@oslo.online.no>
=0ATo: europa-list@matronics.com =0ASent: Tuesday, 2 July 2013, 7:23=0ASubj
ect: SV: Europa-List: Re: wing lift/drag pins=0A =0A=0A=0ARon,=0A=C2-=0AF
rom your message:=0A=C2-=0A> Attached is a diagram that is a pretty good
visualization.=0A> Ron P.=0A> =0A> Here's his reply:=0A> No it=C3=A2=82
=AC=84=A2s not=C3=A2=82=AC=C2 (a good visualization)=0A> =0A> You
have to apply real numbers to those phoney scalers on that figure.=0A> =0A>
At high AOA the drag is significantly higher than shown, but lift not so m
uch=0A> so.=C2- This would pull the L/D resultant much father aft.=0A>
=0A> Those two plots are implying that the L/D of a wing is the same at cru
ise and=0A> at high AOA which we all KNOW is not true! (the reason you neve
r fly a high=0A> performance sailplane near Cl Max!)=0A> =0A=C2-=0AI assu
me it was my illustration that you forwarded to your friend.=C2- If so, I
agree with his statement about L/D =C2-- the vectors are not to scale at
all, and were not intended to be.=C2- I realize, however, that I should
have emphasized this and also increased the length of the wing drag vector
at the high AOA illustration, but this has no bearing on the lift component
issue.=0A=C2-=0AMy message =93 and illustration - had two purposes
, which perhaps your friend was not aware of:=C2- =0A=C2-=0A-=C2-=C2
-=C2-=C2-=C2-=C2-=C2-=C2-=C2- To show that lift has no comp
onent in the direction of flight, regardless of the angle of attack, while
lift may have a =9Cforward=9D component, if "forward" means the
direction the nose is pointing. =C2-=0A-=C2-=C2-=C2-=C2-=C2-
=C2-=C2-=C2-=C2- To show that a glider is pulled forward (in the di
rection of gliding flight) by gravity, not by any lift component.=0A=C2-
=0AI have not made any calculation of the magnitude of the =9Cforward
=9D lift component vs. drag on Europa or any other airplane, which is
why I just referred to arguments and observations presented by others:=C2
- =C2-"At some point it may, as I read the discussion, become larger th
an the wing DRAG=99s component parallel to the centerline in the oppo
site direction, giving a net =9Cforward=9D force on the wing."
=C2- =C2-The magnitude of such a =9Cforward=9D component is
only dependent on the magnitude of the lift and the angle between the cent
erline and the direction of flight.=C2- The magnitude of drag does not co
me in here.=C2- The resultant force on the wing, however, and whether it
acts =9Cforward=9D or =9Cbackward=9D, depends also
on the drag magnitude.=0A=C2-=0AI apologize if I have caused any confusio
n about wing L/D vs. AOA (I don=99t really think I have, though!)=0A
=====================
Message 4
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| Subject: | Re: wing lift/drag pins |
Frans,
> 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.
> 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!
>
> 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
Message 5
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| Subject: | Re: wing lift/drag pins |
Thx Graham,
My sentiments exactly.
And to the question of why the spars are strapped together, and why one pin h
as to be a pip pin, is because we have simple overlapping spars, and not for
k spars, so the asymmetrical load on the pins wants to twist them off, as th
e spar ends gets forced away from the other spar.
Cheers,
Pete
On Jul 2, 2013, at 8:19 AM, GRAHAM SINGLETON <grahamsingleton@btinternet.com
> wrote:
> Svein
> I admire your patience and courtesy, the persistent deniers on this tread
have
> just about exhausted mine! First of all one should start with the facts; w
hen a wing
> fails due to high positive load it claps forwards. Saying "I don't believe
it because it
> doesn't fit my understanding or theory might be described as "an academic r
eaction to an inconvenient truth"
> This "forward lift component" is very counter intuitive, the only way to a
pproach it is to
> refer to a diagram like yours. The criterion a lot of people overlook is t
hat lift is
> perpendicular to line of flight, which is NOT parallel with the centre lin
e of the fuselage.
> Nor is it 180deg from the line of gravity.
> Graham
>
>
> From: Sidsel & Svein Johnsen <sidsel.svein@oslo.online.no>
> To: europa-list@matronics.com
> Sent: Tuesday, 2 July 2013, 7:23
> Subject: SV: Europa-List: Re: wing lift/drag pins
>
> Ron,
>
> =46rom your message:
>
> > Attached is a diagram that is a pretty good visualization.
> > Ron P.
> >
> > Here's his reply:
> > No it=C3=A2=82=AC=84=A2s not=C3=A2=82=AC=C2 (a good visualiz
ation)
> >
> > You have to apply real numbers to those phoney scalers on that figure.
> >
> > At high AOA the drag is significantly higher than shown, but lift not so
much
> > so. This would pull the L/D resultant much father aft.
> >
> > Those two plots are implying that the L/D of a wing is the same at cruis
e and
> > at high AOA which we all KNOW is not true! (the reason you never fly a h
igh
> > performance sailplane near Cl Max!)
> >
>
> I assume it was my illustration that you forwarded to your friend. If so,
I agree with his statement about L/D - the vectors are not to scale at all
, and were not intended to be. I realize, however, that I should have empha
sized this and also increased the length of the wing drag vector at the high
AOA illustration, but this has no bearing on the lift component issue.
>
> My message =93 and illustration - had two purposes, which perhaps yo
ur friend was not aware of:
>
> - To show that lift has no component in the direction of flight, r
egardless of the angle of attack, while lift may have a =9Cforward
=9D component, if "forward" means the direction the nose is pointing.
> - To show that a glider is pulled forward (in the direction of gl
iding flight) by gravity, not by any lift component.
>
> I have not made any calculation of the magnitude of the =9Cforward
=9D lift component vs. drag on Europa or any other airplane, which is why
I just referred to arguments and observations presented by others: "At so
me point it may, as I read the discussion, become larger than the wing DRAG
=99s component parallel to the centerline in the opposite direction, givi
ng a net =9Cforward=9D force on the wing." The magnitude of su
ch a =9Cforward=9D component is only dependent on the magnitude o
f the lift and the angle between the centerline and the direction of flight.
The magnitude of drag does not come in here. The resultant force on the w
ing, however, and whether it acts =9Cforward=9D or =9Cback
ward=9D, depends also on the drag magnitude.
>
> I apologize if I have caused any confusion about wing L/D vs. AOA (I don
=99t really think I have, though!)
>
> Regards,
> Svein
> http://www.matronics.com/Navigator?Europa-Listofollow" target="_blank" h
ref="http://www.matronics.com/contribution">h
>
>
>
>
>
==========================
=========
==========================
=========
==========================
=========
==========================
=========
>
Message 6
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| Subject: | Re: wing lift/drag pins |
Glad I didn't upset everyone {{!-)=0AGraham=0A=0A=0A=0A=0A_________________
_______________=0A From: Pete <peterz@zutrasoft.com>=0ATo: "europa-list@mat
ronics.com" <europa-list@matronics.com> =0ASent: Tuesday, 2 July 2013, 14:5
4=0ASubject: Re: SV: Europa-List: Re: wing lift/drag pins=0A =0A=0A=0AThx G
raham,=0A=0AMy sentiments exactly.=0A=0AAnd to the question of why the spar
s are strapped together, and why one pin has to be a pip pin, is because we
have simple overlapping spars, and not fork spars, so the asymmetrical loa
d on the pins wants to twist them off, as the spar ends gets forced away fr
om the other spar.=0A=0ACheers,=0APete=0A=0A=0A=0AOn Jul 2, 2013, at 8:19 A
M, GRAHAM SINGLETON <grahamsingleton@btinternet.com> wrote:=0A=0A=0ASvein
=0A>I admire your patience and courtesy,- =0A
Message 7
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| Subject: | Re: wing lift/drag pins |
=0A=0AFrans=0AI hope so too, you are a valued member on this forum!=0AThere
was one tragic incident with a Europa Classic, one of the rear lift pins p
ulled out of the threaded plate in the wing. There were doubts re original
construction but nevertheless forward force must have been considerable.=0A
Graham=0A=0A=0A________________________________=0A From: Sidsel & Svein Joh
nsen <sidsel.svein@oslo.online.no>=0ATo: europa-list@matronics.com =0ASent:
Tuesday, 2 July 2013, 13:48=0ASubject: SV: SV: SV: SV: Europa-List: Re: wi
ng lift/drag pins=0A =0A=0A=0AFrans,=0A=C2-=0A=0A> I don't think the forc
es are too large anyway, as the original Europa design=0A> didn't have the
interconnecting bar between the sockets, and the original=0A> structure is
not really that strong with respect to pulling and pushing forces.=0A> =0AF
rans, please promise that you will not be the first one to try that!!=0A=C2
-=0A/////////=0A=C2-=0AI prefer to end my limited contribution to this
tread now, but look very much forward to picking it up again over a cold be
er at the Vichy fly-in.=C2- Perhaps also the beer=99s force may be
determined by which way we are leaning ?=0A=C2-=0ARegar
ds,=0ASvein
Message 8
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| Subject: | Re: wing lift/drag pins |
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@btinternet.com> wrote:
>
>
>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@oslo.online.no>
> To: europa-list@matronics.com
> Sent: Tuesday, 2 July 2013, 13:48
> Subject: SV: SV: SV: SV: Europa-List: 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
>beers force may be determined by which way we are
>leaning ?
>
> Regards,
> Svein
Message 9
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| Subject: | Where did I go wrong? OFF TOPIC |
Cheers,
I am in receipt of another of these gamy emails written in WWI
shorthand - that is a page and a half of letters and figures which defy
decoding in my tiny experience.
I have the terrible feeling that I have failed the group - have
fingered a faulty choice of buttons - have failed to read a perfectly
obvious discretionary warning, - or worse still, am the only one seeing this
block of hieroglyphics which does not exist......and am now for the high
jump at the Home for the Delightfully Bewildered.
What have I done wrong? Is it faulty genetics, a social failing,
even a casually-dropped curse? Help me.
Ferg
C-FFGG
Message 10
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| Subject: | Re: wing lift/drag pins |
Hello All.
What are the rear tie bar and pins used for.
So for all with an open opinion on this topic , this is what Europa Aircraft Company
say about the Tie Bar.
Which gives the full picture, and states Drag and Forward movement.
A requirement to stop the wings fold back, and Forward to stop the wing pulling
forward at high angles of attack, and there's no way this forward force would
rip the rear mounting out from the fuselage, that occurred after something failed
to cause the aircraft to break up.
Quote. Europa
Tie-bar
As the trailing edge lift pin also acts to contain drag loads and the forward component
of lift which is produced at high angles of attack, a tie-bar will be
fitted across the fuselage to react these loads. A general arrangement of the
tie-bar assembly and associated parts is shown in figure 8.
Fig 8.
Alan
Also acts,? what else does it do ?. Don't answer that please.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=403832#403832
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