X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost02.isp.att.net ([204.127.217.102] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3838988 for flyrotary@lancaironline.net; Sun, 06 Sep 2009 08:45:17 -0400 Received-SPF: pass receiver=logan.com; client-ip=204.127.217.102; envelope-from=bbradburry@bellsouth.net Received: from desktop (adsl-146-126-207.mco.bellsouth.net[72.146.126.207]) by isp.att.net (frfwmhc02) with SMTP id <20090906124441H02000gt3ve>; Sun, 6 Sep 2009 12:44:41 +0000 X-Originating-IP: [72.146.126.207] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] Re: DNA muffler Date: Sun, 6 Sep 2009 08:44:44 -0400 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0006_01CA2ECE.48FBE990" X-Mailer: Microsoft Office Outlook 11 Thread-Index: Acou7Jwg5pF+8cQ0Tuecd7nnKghR0AAAl1Gg X-MimeOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 This is a multi-part message in MIME format. ------=_NextPart_000_0006_01CA2ECE.48FBE990 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Ed, We are on opposite sides of this possibility. Seems that if there were more air allowed, the mixture would lean, not richen. This is exactly what I was thinking when I suggested that the muffler might cause more back pressure, lower the air flow, and cause richness.??? What I may be missing is just what the EC-2/3 would do if it saw a certain condition. Explain, please. Bill B _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson Sent: Sunday, September 06, 2009 8:20 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: DNA muffler Hi Mike, Interesting reaction of engine to your DNA muffler. A possible explanation for richer across the board. It appears that the DNA muffler may offer less back pressure to the engine meaning you get more air into the engine at any given rpm. That could increase your manifold pressure and drive the EC2 to enrichen the mixture to compensate. The reason the top end rpm may not change is that at that point there is some other restriction such as the intake, TB, etc that may come into play. Just a theory of course. Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com http://www.andersonee.com http://www.dmack.net/mazda/index.html http://www.flyrotary.com/ http://members.cox.net/rogersda/rotary/configs.htm#N494BW http://www.rotaryaviation.com/Rotorhead%20Truth.htm _____ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills Sent: Saturday, September 05, 2009 11:47 PM To: Rotary motors in aircraft Subject: [FlyRotary] DNA muffler Received my DNA muffler this past week and got it installed and running. Havent flown it yet, but have done some taxi and full power runups. So far I'm a little disappointed. It doesnt appear to be any quieter than my home made muffler. I'll reserve judgement until I actually fly it, but from the cockpit the noise level seems the same, and my buddy standing about 50 ' away said he thought the noise level was the same. One thing not the same - the muffler screwed up my tuning. It appears to be considerably richer now all across the RPM range. And the big bog at the staging point that took me so long to tune out is back with a vengeance. Oddly, in spite of the tune issues it still appears to reach the same static RPM as previously. Looks like the solution for me is going to be the high $ headset and the rest of the world is just going to have to live with it. Mike Wills RV-4 N144MW __________ Information from ESET NOD32 Antivirus, version of virus signature database 3267 (20080714) __________ The message was checked by ESET NOD32 Antivirus. http://www.eset.com ------=_NextPart_000_0006_01CA2ECE.48FBE990 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Ed,

We are on opposite sides of this possibility.  Seems that = if there were more air allowed, the mixture would lean, not richen.  This is exactly what I was thinking when I suggested that the muffler might = cause more back pressure, lower the air flow, and cause = richness.???

 

What I may be missing is just what the EC-2/3 would do if it saw = a certain condition.  Explain, please.

 

Bill B 

 

From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Ed Anderson
Sent: Sunday, September = 06, 2009 8:20 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = DNA muffler

Hi = Mike,

 

Interesting reaction of engine to = your DNA muffler.  A possible explanation for richer across the board.  = It appears that the DNA muffler may offer less back pressure to the engine = meaning you get more air into the engine at any given rpm.  That could = increase your manifold pressure and drive the EC2 to enrichen the mixture to compensate.  The reason the top end rpm may not change is that at = that point there is some other restriction such as the intake, TB, etc that = may come into play.  Just a theory of course.

 

Ed

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills
Sent: Saturday, September = 05, 2009 11:47 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] DNA = muffler

 

Received my DNA muffler this past week and got it = installed and running. Havent flown it yet, but have done some taxi and full power runups. So far I'm a little disappointed. It doesnt appear to be any = quieter than my home made muffler. I'll reserve judgement until I actually fly = it, but from the cockpit the noise level seems the same, and my buddy standing = about 50 ' away said he thought the noise level was the = same.

 

 One thing not the same - the muffler screwed up = my tuning. It appears to be considerably richer now all across the RPM = range. And the big bog at the staging point that took me so long to tune out is = back with a vengeance. Oddly, in spite of the tune issues it still appears to = reach the same static RPM as previously.

 

 Looks like the solution for me is going to be = the high $ headset and the rest of the world is just going to have to live with = it.

 

Mike Wills

RV-4 N144MW



__________ Information from ESET NOD32 Antivirus, version of virus = signature database 3267 (20080714) __________

The message was checked by ESET NOD32 Antivirus.

http://www.eset.com

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