X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fmailhost06.isp.att.net ([204.127.217.106] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3838599 for flyrotary@lancaironline.net; Sun, 06 Sep 2009 01:05:42 -0400 Received-SPF: pass receiver=logan.com; client-ip=204.127.217.106; envelope-from=bbradburry@bellsouth.net Received: from desktop (adsl-146-126-207.mco.bellsouth.net[72.146.126.207]) by isp.att.net (frfwmhc06) with SMTP id <20090906050505H0600nsk00e>; Sun, 6 Sep 2009 05:05:06 +0000 X-Originating-IP: [72.146.126.207] From: "Bill Bradburry" To: "'Rotary motors in aircraft'" References: In-Reply-To: Subject: RE: [FlyRotary] DNA muffler Date: Sun, 6 Sep 2009 01:05:08 -0400 Message-ID: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_001A_01CA2E8E.147228A0" X-Mailer: Microsoft Office Outlook 11 X-MIMEOLE: Produced By Microsoft MimeOLE V6.0.6001.18049 Thread-Index: AcoupL6OH9eVFf2SS4O6ihUdMkCN2wAClM+A This is a multi-part message in MIME format. ------=_NextPart_000_001A_01CA2E8E.147228A0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Mike, Do you have a way to measure the backpressure ahead of the muffler? Does the design of the muffler appear that it would cause a restriction greater than you already had? Did your map table change, or does it just run richer? What is different about the map table at the stage point? Bill B _____ 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 ------=_NextPart_000_001A_01CA2E8E.147228A0 Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

Mike,

Do you have a way to measure the backpressure ahead of the muffler?  Does the design of the muffler appear that it would cause = a restriction greater than you already had?

Did your map table change, or does it just run richer?  = What is different about the map table at the stage = point? 

 

Bill B

 

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

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