---------------------------------------------------------- Europa-List Digest Archive --- Total Messages Posted Tue 09/12/23: 4 ---------------------------------------------------------- Today's Message Index: ---------------------- 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 _____________________________________ Time: 02:58:11 AM PST US Subject: Europa-List: Re: Cork insulation for noise reduction From: "JohnFrance" <77alembert@gmail.com> 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 _____________________________________ Time: 03:20:49 AM PST US From: Pete Zut Subject: Re: Europa-List: 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 > > =========== =========== =========== =========== =========== > > ________________________________ Message 3 _____________________________________ Time: 01:41:43 PM PST US Subject: Europa-List: Re: Cork insulation for noise reduction From: "n7188u" 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 Read this topic online here: http://forums.matronics.com/viewtopic.php?p=511423#511423 ________________________________ Message 4 _____________________________________ Time: 04:14:06 PM PST US Subject: Europa-List: Re: Cork insulation for noise reduction From: "Area-51" 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. 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