X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao104.cox.net ([68.230.241.42] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTP id 3840561 for flyrotary@lancaironline.net; Mon, 07 Sep 2009 21:32:14 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.42; envelope-from=rv-4mike@cox.net Received: from fed1rmimpo02.cox.net ([70.169.32.72]) by fed1rmmtao104.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20090908013140.BDKU14181.fed1rmmtao104.cox.net@fed1rmimpo02.cox.net> for ; Mon, 7 Sep 2009 21:31:40 -0400 Received: from wills ([68.105.80.138]) by fed1rmimpo02.cox.net with bizsmtp id e1Xc1c00J2z3ATG041XfgX; Mon, 07 Sep 2009 21:31:39 -0400 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=ayC55rCoAAAA:8 a=arxwEM4EAAAA:8 a=QdXCYpuVAAAA:8 a=7g1VtSJxAAAA:8 a=ekHE3smAAAAA:20 a=UretUmmEAAAA:8 a=Ia-xEzejAAAA:8 a=nUuTZ29dAAAA:8 a=BuP-N3FbXmc8BjZbV9cA:9 a=YMx0B2TLncZNtvxeOxUA:7 a=g0ttLvpkfqiqzB-MXt6bvbDcpAsA:4 a=EzXvWhQp4_cA:10 a=nqumd8Pw8gIp1WPD:21 a=hkjAXCgbYkoTdISC:21 a=SSmOFEACAAAA:8 a=tsLfCXkwTx-OGd4JxzIA:9 a=PYsvU7QpzVByj_wPFFAA:7 a=YbtxNi7hIHdbWdIAgMyzOu4zml0A:4 X-CM-Score: 0.00 Message-ID: <046815964D4141AC81F67E20EDB2E45E@wills> From: "Mike Wills" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: DNA muffler Date: Mon, 7 Sep 2009 18:31:36 -0700 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0042_01CA2FE9.6F078650" 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 This is a multi-part message in MIME format. ------=_NextPart_000_0042_01CA2FE9.6F078650 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I flew for an hour today and confirmed that this muffler is no better at = muffling than my home made one was. At least it doesnt appear to have = cost me any power. I'll try Mark's suggestion of reducing the outlet, = but its already 2.25" and I'm hesitant to reduce it below 2". I dont = have much hope that a reduction to 2" will have much effect on sound = level. Anyone got any good suggestions for some relatively light weight sound = proofing material that I can add to the floor boards and firewall? I = hate to add the weight, but I hate the noise more. 32.5 hours to go to complete Phase 1 test flying. Mike Wills RV-4 N144MW ----- Original Message -----=20 From: Ed Anderson=20 To: Rotary motors in aircraft=20 Sent: Sunday, September 06, 2009 8:55 AM Subject: [FlyRotary] Re: DNA muffler Well, I can always be wrong, Bill. However, more air mass flow at the = same rpm (due to "theoretical" better flow, i.e. Better volumetric = efficiency) would mean the EC2 would see higher manifold pressure and = should respond by enrichening the mixture to match - I mean that is what = the EC does- match fuel flow to manifold pressure. Now you would think = that if it matched the higher manifold pressure accurately then while = more fuel would be flowing - the air/fuel ratio (which is what we are = looking at on our indicator) should theoretically remain the same. = Could be the EC "over compensated" ?=20 =20 Perhaps another way of looking at is with the old muffler which gave a = certain manifold pressure at rpm X would then point to the corresponding = manifold pressure bin in the EC2 MCT. Now if at the same rpm with the = new muffler the airflow mass flow is greater - then the manifold = pressure at X rpm will be corresponding greater. Since the EC2/3 is = using manifold pressure to point to the correct bin - it is now pointing = a couple of bins higher in the map. Normally the higher you are in the = map the more fuel is signaled to flow. So Mike would then have to = "re-adjust" the MCT table to match the new volumetric efficiency = increase. =20 Now if the new muffler was producing more back pressure then the = airflow would be lower for the same RPM or the Volumetric efficiency = would be somewhat worst than the with the old muffler. So if the lower = air mass flow corresponds to a lower manifold pressure then the EC2 = should be point a couple of bins lower in the MCT which normally would = signal less fuel is required and injected to match the lower air flow.=20 =20 Or at least that is my take on it. =20 Perhaps Tracy is loafing around today {:>) and will come on line the = real explanation. =20 Ed =20 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 Bill Bradburry Sent: Sunday, September 06, 2009 8:45 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: DNA muffler =20 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.??? =20 What I may be missing is just what the EC-2/3 would do if it saw a = certain condition. Explain, please. =20 Bill B=20 =20 -------------------------------------------------------------------------= ----- 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, =20 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. =20 Ed =20 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 =20 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. =20 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. =20 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. =20 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 __________ 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_0042_01CA2FE9.6F078650 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
I flew for an hour today and confirmed = that this=20 muffler is no better at muffling than my home made one was. At least it = doesnt=20 appear to have cost me any power. I'll try Mark's suggestion of reducing = the=20 outlet, but its already 2.25" and I'm hesitant to reduce it below 2". I = dont=20 have much hope that a reduction to 2" will have much effect on sound=20 level.
 
Anyone got any good suggestions for = some relatively=20 light weight sound proofing material that I can add to the floor boards = and=20 firewall? I hate to add the weight, but I hate the noise = more.
 
32.5 hours to go to complete Phase 1 = test=20 flying.
 
Mike Wills
RV-4 N144MW
----- Original Message -----
From:=20 Ed=20 Anderson
Sent: Sunday, September 06, = 2009 8:55=20 AM
Subject: [FlyRotary] Re: DNA=20 muffler

Well, I can = always be=20 wrong, Bill.  However, more air mass flow at the same rpm (due to = =93theoretical=94 better flow, i.e. Better volumetric efficiency) = would mean the=20 EC2 would see higher manifold pressure and should respond by = enrichening the=20 mixture to match =96 I mean that is what the EC does- match fuel flow = to=20 manifold pressure.  Now you would think that if it matched the = higher=20 manifold pressure accurately then while more fuel would be flowing =96 = the=20 air/fuel ratio (which is what we are looking at on our indicator) = should=20 theoretically remain the same.  Could be the EC =93over = compensated=94 ?=20

 

Perhaps = another way=20 of looking at is with the old muffler which gave a certain manifold = pressure=20 at rpm X would then point to the corresponding manifold pressure bin = in the=20 EC2 MCT.  Now if at the same rpm with the new muffler the airflow = mass=20 flow is greater - then the manifold pressure at X rpm will be = corresponding=20 greater.  Since the EC2/3 is using manifold pressure to point to = the=20 correct bin =96 it is now pointing a couple of bins higher in the = map. =20 Normally the higher you are in the map the more fuel is signaled to=20 flow.  So Mike would then have to =93re-adjust=94 the MCT table = to match the=20 new volumetric efficiency increase.

 

Now if the = new=20 muffler was producing more back pressure then the airflow would be = lower for=20 the same RPM or the Volumetric efficiency would be somewhat worst than = the=20 with the old muffler.  So if the lower air mass flow corresponds = to a=20 lower manifold pressure then the EC2 should be point a couple of bins = lower in=20 the MCT which normally would signal less fuel is required and injected = to=20 match the lower air flow.

 

Or at least = that is=20 my take on it.

 

Perhaps = Tracy is = loafing around=20 today {:>) and will come on line the real=20 explanation.

 

Ed

 

Ed=20 Anderson

Rv-6A = N494BW Rotary=20 Powered

Matthews,=20 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.r= otaryaviation.com/Rotorhead%20Truth.htm

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Bill Bradburry
Sent: Sunday, September 06, = 2009 8:45=20 AM
To: = Rotary motors in aircraft
Subject: [FlyRotary] Re: DNA=20 muffler

 

Ed,

We are on opposite sides of this = possibility. =20 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=20 muffler might cause more back pressure, lower the air flow, and cause=20 richness.???

 

What I may be missing is just what the = EC-2/3 would do=20 if it saw a certain condition.  Explain,=20 please.

 

Bill = B 

 

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

Hi=20 Mike,

 

Interesting = reaction=20 of engine to your DNA muffler.  A possible explanation for richer = across=20 the board.  It appears that the DNA muffler may offer less back = pressure=20 to the engine meaning you get more air into the engine at any given = rpm. =20 That could increase your manifold pressure and drive the EC2 to = enrichen the=20 mixture to compensate.  The reason the top end rpm may not change = is that=20 at that point there is some other restriction such as the intake, TB, = etc that=20 may come into play.  Just a theory of=20 course.

 

Ed

 

Ed=20 Anderson

Rv-6A = N494BW Rotary=20 Powered

Matthews,=20 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.r= otaryaviation.com/Rotorhead%20Truth.htm

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Mike Wills
Sent: Saturday, September 05, = 2009 11:47=20 PM
To: = Rotary motors in aircraft
Subject: [FlyRotary] DNA=20 muffler

 

Received my DNA muffler = this past=20 week and got it installed and running. Havent flown it yet, but have = done some=20 taxi and full power runups. So far I'm a little disappointed. It = doesnt appear=20 to be any quieter than my home made muffler. I'll reserve judgement = until I=20 actually fly it, but from the cockpit the noise level seems the same, = and my=20 buddy standing about 50 ' away said he thought the noise level was the = same.

 

 One thing not the = same - the=20 muffler screwed up my tuning. It appears to be considerably richer now = all=20 across the RPM range. And the big bog at the staging point that took = me so=20 long to tune out is back with a vengeance. Oddly, in spite of the tune = issues=20 it still appears to reach the same static RPM as=20 previously.

 

 Looks like the = solution for=20 me is going to be the high $ headset and the rest of the world is just = going=20 to have to live with it.

 

Mike=20 Wills

RV-4=20 N144MW



__________ Information from ESET = NOD32=20 Antivirus, version of virus signature database 3267 (20080714)=20 __________

The message was checked by ESET NOD32 = Antivirus.

http://www.eset.com



__________ Information from ESET = NOD32=20 Antivirus, version of virus signature database 3267 (20080714)=20 __________

The message was checked by ESET NOD32 = Antivirus.

http://www.eset.com

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