Today's Message Index:
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1. 04:57 AM - Re: Re: Muffler (silencer) suspension puzzle (Pete)
2. 05:21 AM - Re: Muffler (silencer) suspension puzzle (Area-51)
3. 10:59 AM - Re: Finishing tips (Hitchflight)
4. 12:59 PM - Re: Finishing tips (dmac7)
5. 01:11 PM - Re: Finishing tips (Kelvin Weston)
6. 01:30 PM - Re: Finishing tips (Kelvin Weston)
7. 06:04 PM - Re: the Obsidian Files - So Much Noise!!! (n7188u)
8. 06:23 PM - Considering a few mods. Opinions? (n7188u)
9. 07:30 PM - Re: Considering a few mods. Opinions? (Area-51)
Message 1
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| Subject: | Re: Muffler (silencer) suspension puzzle |
or in my case a pocketed dog gearbox, heavy warpdrive prop, eaten plastic gearbox
thrust washer (twice), and lightly loaded cruise prop resonance, resulting
in dramatic exhaust cracking (three times).
Replaced the pocketed dogs and plastic washer, changed to a lighter prop, and no
more cracked exhaust. Magic.
Cheers,
PeteZ
> On Mar 25, 2023, at 10:39 PM, Area-51 <goldsteinindustrial@gmail.com> wrote:
>
>
> Nearly all and everything contemporary produced is completely designed within
a digital computer specified environment; from electronics to mechanical; covering
design criteria such as Thermal Expansion & Conductivity, Modal Frequency
Vibrational Response, Dynamic Physical Loads & Gravity, Material Elasticity
Stress & Strain, Chemical Interactions... This is a very basic matrix of R&D analysis.
>
> When a company such as Bombardier develop a power train it is run through the
above matrix before being produced and released for industry use.
>
> The factory supplied 9XX exhaust system will have the above matrix applied along
with field testing results which are fed back into the design process upon
a "Continual Improvement" basis, which the end user sees as optional or mandatory
factory Service Bulletins.
>
> This closed loop system quickly falls apart when third party aftermarket components
are brought into the mix; some may cause premature failure, others may
prevent it; it depends upon the applied knowledge of who ever is producing the
component.
>
> The whole exhaust is constantly vibrating at (x)hz at (x)deg and will be tested
at the factory based upon the typical operating ranges of the power unit being
in the vicinity of 5100rpm and (x)deg give or take 15% either side. Stress
and strain fatigue points of the exhaust system will naturally be found around
both bending points, and attachment points. Hard mounting the exhaust muffler
to the engine block moves any inertia forces of the exhaust into the engine
block which may or may not be designed to support such loads beyond (x)hrs of
usage at (x)rpm.
>
> A rough running engine or loose fixing somewhere in the mix adds another dimension
of vibration into the fatigue failure equation.
>
> This why its important to keep any motor well serviced and tuned and running
smooth.
>
> The short answer to the question is "Cycle Count" but that is just going to be
too cryptic for most to understand.
>
>
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=510499#510499
>
>
>
>
>
>
>
>
>
Message 2
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| Subject: | Re: Muffler (silencer) suspension puzzle |
Very interesting!!
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510503#510503
Message 3
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| Subject: | Re: Finishing tips |
Hi Dan
After some digging I have refreshed the page you referred to so as to recognise
and credit the probable authors.
Attribution: Thanks to George Sychrovsky & the late Nigel Graham
Hope this helps.
We are most fortunate that many good people have donated their achievements in
life to posterity.
Have a contact reference that I will email to you separately.
Regards
Bob
If anyone spots any errors or omissions on the Europa Club website please advise
by email to secretary@theeuropaclub.org and we would endeavour to fix.
danbish99 wrote:
> Any idea who wrote this article? Has some excellent tips but I have a few questions
for the author. It's posted on the Europa Club site.
>
> Thanks,
>
> Dan
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510508#510508
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| Subject: | Re: Finishing tips |
Thx Jerry, good write up on finishing. I will try to add a Youtube video on a method
used by Cory Bird on his aircraft called " Symmetry " a 2004 Oshkosh Grand
champion winner. He called his finish technique "the epoxy wipe method"
https://www.youtube.com/watch?v=43K1qwoHbnc&t=22s
If the link doesn't work just search Youtube for, epoxy wipe method composite aircraft
finishing.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510510#510510
Message 5
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| Subject: | Re: Finishing tips |
Hi Dan
The original web article can be found here:
http://curedcomposites.com/index.html
or the page on finishing here:
http://curedcomposites.com/finish.html
Another good article on finishing is Wayne Hicks Cozy IV project:
http://ez.canardaircraft.com/www.ez.org/canardpages/pages/waynehicks/index.html
See Chapter 25 on Finishing
--------
Regards
Kelv Weston
Kit 497
kelv@kdweston.co.uk
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510511#510511
Message 6
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| Subject: | Re: Finishing tips |
Hi Dan
A pdf attached of the "Epoxy Wipe" or "Skim Coating" method extracted from Wayne
Hicks Cozy project.
There is also lots of great finishing advice on this forum from Bud Yearly and
the late great Nev Eyre.
--------
Regards
Kelv Weston
Kit 497
kelv@kdweston.co.uk
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510512#510512
Attachments:
http://forums.matronics.com//files/skimcoating_171.pdf
Message 7
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| Subject: | Re: the Obsidian Files - So Much Noise!!! |
Today I finally had a chance to get a longer flight in. It's hard to say how much
improvement the install of the sound deadening material on the air box has
on the internal noise. But there is certainly improvement!! The flight today was
very pleasant and more enjoyable. But what really struck me is that, as A51
experienced, I had to lower the intercom volume quite a bit since it felt too
loud. Same thing when I was playing music as I generally do. So, even though
I can still hear relatively high frequency sound, but maybe less, it seems that
overall there is a reduction in noise.
But, I have to admit this is all just based on perception. It is indeed hard to
quantify the change. But I have to say that despite the increase in weight, it
is a keeper.
On a different note: I finished rebuilding my spray booth and getting closer to
starting the painting process. I will hold off taking the airplane apart this
week to see if I fly it to Sun n Fun but by next weekend it will come apart so
no more flying until it is done. I also have a couple of pending jobs I want
to perform on the airframe.
Chris
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510513#510513
Message 8
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| Subject: | Considering a few mods. Opinions? |
Dear Europa Friends,
Since my airplane is coming apart for painting, I wanted to implement the cockpit
widening mod 67. Any negative experiences with doing this? I think it would
help increase the comfort of the airplane as I notice that after a x-country
flight my left arm hurts a little from rubbing on the door frame.
Since the door will be worked on I am going to change the gas strut attach point
(my door was already built with the old style attach point). I know this is
basically a must although the current configuration has worked OK.
At last, anyone has any experience with installing a monowheel wheel pant? I have
a kit for that and was thinking about installing the front part only. I am
not doing it for the speed as I know the wheel is basically blocked by the cowling's
exhaust but I think it could help seal the wheel well better and possibly
reduce turbulent air getting into it (noise).
Chris
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510514#510514
Message 9
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| Subject: | Re: Considering a few mods. Opinions? |
Attached is a rudimentary cross section of free stream air through the forward
fuselage voids without lower cowl ducting.
>From experience flying in a mono with wheel fairing fitted; with ANR switched
on at the time there was no detectible change in cabin noise volume compared to
flying in 181. However the degree off air flow through the cockpit was greatly
multiplied due to the wheel well being mostly sealed off during flight; not
fitting the rear portion of the fairing will greatly diminish this ventilation
feature.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=510515#510515
Attachments:
http://forums.matronics.com//files/9727fbf9_885d_4ac6_bc0d_a372d13ea377_675.jpeg
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