The (substantial) wear marks on W26A show that is was installed the correc
t way around.
The wear mark on the inside vertical surface of W26 just above the central
bolt indicate that at some point W26A was leaning heavily on W26 in a 'nega
tive g' direction of loading, which may explain how it then broke i.e. the
weight of the wing transmitted in bending through the lift pin caused W26A
to lever against W26.
That wouldn't occur during a normal flight maneuver and when properly rigge
d. Perhaps the downward leverage occurred during derigging after removing t
he spar pins, and assuming the spar cups were misplaced.
I'd check the lift pins for bending too and that these are not angled (or b
ent) above the centreline of the inboard spar projections (and/or that W26
has been set vertically).
Duncan Mcf.
> On 07 September 2020 at 14:31 Bud Yerly <budyerly@msn.com> wrote:
>
>
> Sorry to hear of your issues.
>
>
>
> The failure of the socket indicates the crash may have been more seve
re than anticipated.
>
> In all my years, I=99ve seen corrosion on older socket parts th
at were not as well protected as the new bits are. I have never seen a fai
lure in the 26A as this was a well engineered and tested part by Europa. I
f installed backwards, this can happen.
>
>
>
> Please contact Europa Aircraft because the W26 part assembly has not
been an issue and replacement of the corroded items may be smart. This are
a is a critical flight component and the annual inspection and repair may h
ave missed this part may have been damaged or assembled incorrectly. If th
e socket inner W26B failed, was the interior tube and attachments properly
installed, checked and inspected is the question.
>
>
>
> Loctite is between the barrel and that thin rectangular piece you cal
l it so they operate as a unit. The wing pin goes into the fully assembled
socket and allows it to move up and down just a bit. If not Loctited the
barrel can rotate and make pin insertion more difficult. (Frankly, during
wing install, simply note the orientation of the barrel is all that is need
ed.) Note that the assembly thin side goes on the fuselage side. Don
=99t get that backwards as it builds up stress and may be a part of the fai
lure you see.
>
>
>
> As far as the structural strength, the yoke piece 26A and the barrel
26C carry the load of the wing pulling forward under max G load. This barr
el is designed to move up and down.
>
>
>
> As for the Rotax 914:
>
> There is a long and boring troubleshooting guide on my website on kee
ping the 914 running true. The carbs are easily rebuilt with proper attent
ion to detail. I find the Rotax engine forum informational, but doesn
=99t cover in enough detail. I do find the videos provided by Rotax to
be quite complete. The paper I did covers various phases and expands troub
leshooting. See the techniques section for an updated version since publis
hed in the Europa Club magazine.
>
>
>
> Bud Yerly
>
> www.customflightcreations.com
>
> Sent from Mail https://go.microsoft.com/fwlink/?LinkId=550986 for W
indows 10
>
>
>
> From: Erik Dahlb=C3=A4ck mailto:erik@erikdahlbeck.com
> Sent: Sunday, September 6, 2020 5:18 PM
> To: europa-list@matronics.com mailto:europa-list@matronics.com
> Subject: Europa-List: Rear wing root socket problems
>
>
>
> Hello,
>
> First time posting here, hoping my attached photos are small enough,
etc...
>
> I'm trying to get Europa SE-XRX airworthy again after being grounded
for
> two years. At first due to some hard-to-diagnose carburettor problems
.
> 914 float bowls, enough said... If interested, I have a post about it
> over at Rotax-Owners:
> https://nam11.safelinks.protection.outlook.com/?url=https%3A%2F%2Fw
ww.rotax-owner.com%2Fen%2F912-914-technical-questions%2F6881-914ul-carburet
tor-gremlins%3Fstart%3D15&data=02%7C01%7C%7C8482b0ef213641821e7208d85
2aa5b72%7C84df9e7fe9f640afb435aaaaaaaaaaaa%7C1%7C0%7C637350238926500351&
;sdata=pMvGV5%2BI41Zjnn3nQnSV8Wo37dGxDwnn9%2Ff%2Bu5P7T%2F0%3D&reserve
d=0
>
>
> PROBLEM NO 1
>
> Anyway, after fixing the engine and while doing the annual together w
ith
> the previous owner/builder, it was discovered that the rear wing sock
et
> housing, part W26B, starboard side, was cracked in two parts. Further
> inspection showed that also the port side was cracked, albeit not hav
ing
> split in two just yet. Please see attached photos.
>
> I've got the spares from the manufacturer however, I'm curious if thi
s
> is a known problem? Any thoughts on what could be the cause? Anything
> further to look out for?
>
> My local mechanic seemed just as puzzled as I was when looking at how
> thin this part is. I mean what is it, 2 mm?
>
> One thing to consider: The aircraft was built as a monowheel but cras
hed
> on takeoff during flight testing, making a hard landing and a ground
> loop. The incident was traced to a construction error in the control
> line attachment to the rudder, causing alterations in the design (som
e
> of might be familiar with this). The aircraft was then repaired (by s
ome
> sailplane workshop that seemed to know what they were doing, I've see
n
> the photos at least). Among other things it got a new tail, a CS prop
> and was rebuilt as a trigear. Might this new discovery simply be resi
due
> of that old incident?
>
> Also, the builder's manual states that the W26B and C parts should be
> loctited together. However, there was no trace of this. I'm not sure
if
> that instruction has been there since the beginning or if it could be
a
> later revision? However, I sort of have my doubts as to some loctite
> being able to strenghten this construction enough to not break from
> whatever broke this...?
>
> Finally, any thoughts on how to reassemble these parts? Where does th
e
> Loctite go? Just on the barrel and make sure the holes align before i
> dries? How to you avoid getting loctite on the surfaces between the
> barrel and the socket body (W26A)?
>
>
> PROBLEM NO 2
>
> Due to various reasons, I only got around to cleaning the grease off
the
> rear socket assemblies, in preparation for reassembly, but doing the
> loctite-work in a cold hangar, etc, and also enlisting the help of th
e
> very busy local mechanic, was more than I could get done before last
winter.
>
> Now, on inspection, the W26A socket bodies show signs of corrosion.
> Please see the other attached photos. Anyone have an opinion on just
how
> bad this is? Do they also need changing? And does that require
> composite-work? I've been looking through the builder's manual but I'
m
> afraid I'm not quite up to understanding all of it.
>
>
> Any thoughts on both of the above issues would be greatly appreciated
!
>
>
> Sincerely,
>
> Erik Gunneland Dahlb=C3=A4ck
> Link=C3=B6ping, Sweden
> Europa SE-XRX
>
>
>
|