Today's Message Index:
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1. 02:58 AM - Re: Cork insulation for noise reduction (JohnFrance)
2. 03:20 AM - Re: Re: Cork insulation for noise reduction (Pete Zut)
3. 01:41 PM - Re: Cork insulation for noise reduction (n7188u)
4. 04:14 PM - Re: Cork insulation for noise reduction (Area-51)
Message 1
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| Subject: | Re: Cork insulation for noise reduction |
Having flown a couple of hours recently in a friends WT9 I was amazed how quiet
it is compared to my Europa. In the WT9 a conversation is possible even without
headsets whereas my Europa is very uncomfortable with headsets removed.
I think there is a lot of direct noise transmission through the engine mounts as
the rubber mounts are very hard and lets face it arrives in the cockpit under
our feet.
Does anyone have any information on what lining all the front facing inside walls
of the cockpit module with 3mm of cork might have on sound attenuation?
--------
Europa mono Nr 192
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=511421#511421
Message 2
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| Subject: | Re: Cork insulation for noise reduction |
Indeed when I changed to the softer industry-std Lords for engine mounts,
my cabin noise decreased markedly. I find that at anything over 120knots
and the airstream noise is greater than the engine noise. Prop noise (3
blade CS E-prop) is also noticeable over the engine noise.
Cheers,
PeteZ
On Tue, Sep 12, 2023 at 6:11=AFAM JohnFrance <77alembert@gmail.com> w
rote:
>
> Having flown a couple of hours recently in a friend=99s WT9 I was a
mazed how
> quiet it is compared to my Europa. In the WT9 a conversation is possible
> even without headsets whereas my Europa is very uncomfortable with
> headsets removed.
> I think there is a lot of direct noise transmission through the engine
> mounts as the rubber mounts are very hard and let=99s face it arriv
es in the
> cockpit under our feet.
> Does anyone have any information on what lining all the front facing
> inside walls of the cockpit module with 3mm of cork might have on sound
> attenuation?
>
> --------
> Europa mono Nr 192
>
>
> Read this topic online here:
>
> http://forums.matronics.com/viewtopic.php?p=511421#511421
>
>
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>
>
Message 3
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| Subject: | Re: Cork insulation for noise reduction |
Today I removed the engine and instrument module in my airplane in preparation
for painting the fuselage. It was actually quite easy to do albeit, like everything,
it did involve some work.
Although I was tempted to remove the firewall and insulated, I looked at it and
honestly don't want to remove it. Too much work and I had enough of disassembling
stuff. So if I am going to apply sound insulation it will have to be on the
engine side.
One thing I could consider is to try the lord mounts since the engine is off so
it would be easy to try.
I also think that our firewall could be a good source of noise since that thing
is a nice drum and could use some sound proofing.
But I also agree with John that the engine mount, being attached to the wheel well,
probably acts as a resonator and transmits a good deal of noise to the interior.
Chris
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http://forums.matronics.com/viewtopic.php?p=511423#511423
Message 4
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| Subject: | Re: Cork insulation for noise reduction |
Chris, the firewall from memory is about 6.0mm phenolic material and the drumming
qualities are quite different to the rest of the fuselage; higher pitched around
2000hz. If you have a dB app on your phone you can work these out by going
around tapping sharply with finger tip and noting all the areas identified.
On 181's firewall this is the forward facing footwell surfaces and the upper
vertical firewall/cabin surface. Engine vibration travels through the entire airframe.
These surfaces can often act more like a speaker cone vibrating when excited by
another "modal" frequency impacting anywhere upon the body.
Technicals aside the DCI produced butyl mat only needs to be applied to 10% of
the entire drumming surface area to still be most effective. Other brands will
require 20% coverage due to density. It can be applied on the interior side of
the firewall.
DCI also produce a 3M adhesive polyester backed AL sheet which I have used successfully
lining automotive roof panels; it's very light weight, fire resistant,
sound and heat insulating, applied across entire panel, and looks great when
the edges are folded over to form an edge bead.
The 3M adhesive is a "once on never comes off" solution. You get one chance only
at putting on. On composites it will tear the base material layer away from
the body before it comes away from the adhered surface. So finger tip size tacking
points to align followed by soft paint roller application is required.
Read this topic online here:
http://forums.matronics.com/viewtopic.php?p=511425#511425
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