I used the same stuff as well. seemed to do some good, but I probably could have done a better job sealing the firewall. I have 1.25" on the floor and firewell, and 1/4" on the sidewalls. That made a nice base for the leather too. One problem with the closed cell foam is that it expands quite a bit at altitude, expecially the thick stuff. Above 10,000' my floor piece (covered with carpet) expands enough that it no longer seats and it partly lifts off the floor.
Dave Leonard
On Sun, Sep 13, 2009 at 8:57 AM, Mike Wills <rv-4mike@cox.net> wrote:
I should have mentioned. My original muffler (which I am reinstalling) had a turndown of about 20 - 30 degrees. The DNA had no turndown. Again, no detectable difference in noise or performance between the two.
Found a how-to from the manufacturer of the black foam Mark and Tracy mentioned here:
http://www.soundproofing.org/infopages/soundprf.html
Wish I'd installed this stuff in the floorboards before I closed the interior structure.
Sent: Saturday, September 12, 2009 1:03 PM
Subject: [FlyRotary] Re: cockpit soundproofing
Mark Steitle wrote:
Mike,
My first line of defense against the noise is an ANR headset. That's a given.
I purchased some black foam from ACS that I installed on the interior walls and floor. From what I've read a lot of the noise comes in through the firewall and windows. Not much you can do about the windows, but it seems that a generous amount of soundproofing on the firewall will help the most. Lastly, you can turn the exhaust down so that it is directed away from the occupants? Or, run it back behind the pax, and fly faster than the speed of sound so it can't catch up to you. Mark S.
On Sat, Sep 12, 2009 at 10:15 AM, Mike Wills < rv-4mike@cox.net <mailto: rv-4mike@cox.net>> wrote:
I asked a few days ago and got no replies. Since things are a bit slow on the list now I'll try again. Anyone have any recommendations for a decent soundproofing material that I can add to my firewall and floorboards to tame this racket? Maybe the rest
of the world will have to deal with the noise, but at least I can try to make it a little more pleasant for me. Mike Wills RV-4 N144MW
Running it back past the occupants can actually be effective. Turning it down adds drag. I've often wondered why no one has tried carrying the pipes down several inches below the fuselage before turning them aft, and installing streamline inserts aft of the downpipes & between the fuselage bottom & the horizontal run of pipe, to get smooth air between the fuselage & the now-parallel exhaust stream.
Charlie -- Homepage: http://www.flyrotary.com/Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html
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David Leonard
Turbo Rotary RV-6 N4VY
http://N4VY.RotaryRoster.net
http://RotaryRoster.net
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