X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao101.cox.net ([68.230.241.45] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3849094 for flyrotary@lancaironline.net; Sun, 13 Sep 2009 11:57:42 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.45; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao101.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20090913155704.EBKE16492.fed1rmmtao101.cox.net@fed1rmimpo02.cox.net> for ; Sun, 13 Sep 2009 11:57:04 -0400 Received: from wills ([68.105.80.138]) by fed1rmimpo02.cox.net with bizsmtp id gFx31c0072z3ATG04Fx5Mo; Sun, 13 Sep 2009 11:57:05 -0400 X-VR-Score: 20.00 X-Authority-Analysis: v=1.0 c=1 a=pMn5UCuSAAAA:8 a=pedpZTtsAAAA:8 a=Ia-xEzejAAAA:8 a=kviXuzpPAAAA:8 a=7g1VtSJxAAAA:8 a=D6HvLtFCFM-3lSI59zoA:9 a=7SL-0yY2kPZCrsmjG5cA:7 a=sTdN3bgr-HRRqACvCh5F-w5oPCUA:4 a=XFWJeiLW26sA:10 a=eJojReuL3h0A:10 a=EzXvWhQp4_cA:10 a=4vB-4DCPJfMA:10 X-CM-Score: 0.00 Message-ID: From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: cockpit soundproofing Date: Sun, 13 Sep 2009 08:57:04 -0700 MIME-Version: 1.0 Content-Type: text/plain; format=flowed; charset="iso-8859-1"; reply-type=response Content-Transfer-Encoding: 7bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5843 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 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. Mike Wills RV-4 N144MW ----- Original Message ----- From: "Charlie England" To: "Rotary motors in aircraft" 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 > > 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 >