X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from smtp1.av-mx.com ([137.118.16.57] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3472284 for flyrotary@lancaironline.net; Mon, 02 Feb 2009 09:41:54 -0500 Received-SPF: pass receiver=logan.com; client-ip=137.118.16.57; envelope-from=res12@fairpoint.net Received: from main (dblt-74-209-35-223.gtcom.net [74.209.35.223]) (Authenticated sender: res12@fairpoint.net) by smtp1.av-mx.com (Postfix) with ESMTP id 7F6F32905CB for ; Mon, 2 Feb 2009 09:40:51 -0500 (EST) Message-ID: <560E6C21C1D240CA91C23ACE3677A987@main> From: "Richard Sohn" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: My New DNA Muffler Date: Mon, 2 Feb 2009 08:40:56 -0600 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0021_01C98511.F72587E0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 This is a multi-part message in MIME format. ------=_NextPart_000_0021_01C98511.F72587E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Mark, the only time sound measurements are useable is if the conditions are = the same every time you measure. You never know exactly which of the = sound is generated by the source and which by secondary resonators or = reflectors.=20 This should not be discouraging, just keep the measuring condition as = close as possible the same, and you can judge which way your efforts are = going. I my self will be in this situation hopefully soon.=20 FWIW. Richard Sohn N2071U ----- Original Message -----=20 From: Mark Steitle=20 To: Rotary motors in aircraft=20 Sent: Monday, February 02, 2009 7:14 AM Subject: [FlyRotary] Re: My New DNA Muffler After posting my original message I thought I should clarify a couple = of things about my noise level readings. These were taken inside the = a/c, but with the door open and the carpet and soundproofing removed = from the floor. The single gullwing door opens up and would tend to = catch the sound the same as cupping your hands over your ears does. The = exhaust exits the cowl on the left side, just aft of the firewall and = below the door opening. I was parked on concrete, so with the muffler = pointed back and down at about 45*, the readings were exaggerated by the = sound bouncing off of the concrete. Hopefully, that wouldn't happen = when flying. =20 Mark S. On Sun, Feb 1, 2009 at 9:19 PM, Mark Steitle = wrote: Richard,=20 I think you're right on with your comment. I cobbled up the new = muffler onto the old manifold and ran it up to 4000 rpm today. At = 1500-1600, the noise level inside the a/c was ~89 db, at 4000 it was = 102db. It wasn't any noisier than the burned out Hushpower II, but it = wasn't much quieter either. Unfortunately, with the setup I had, I = didn't want to run it any harder, but it did seem to work better the = faster I ran the engine. It wouldn't be any trouble to neck down the = exit from 3" to 2". More on that later... Mark S. =20 On Sat, Jan 31, 2009 at 9:09 AM, Richard Sohn = wrote: With the inlet and outlet the same size, I would not be surprised = if it does very little noise reduction, if any. Some tests in the past = have shown that a smaller exit makes a considerable difference in sound = level with moderate loss of power.=20 FWIW. Richard Sohn N2071U ----- Original Message -----=20 From: Mark Steitle=20 To: Rotary motors in aircraft=20 Sent: Saturday, January 31, 2009 8:48 AM Subject: [FlyRotary] My New DNA Muffler Hey Guys, My new DNA muffler arrived yesterday so I thought I would post a = couple of pictures with some information and first impressions. It appears to be very well built, all tig welded, and no = packing to burn out. It weighs just under 5#, which is half of what the = Hushpower II weighs, so if it works, I will have reduced my fwf weight = by 5#. To be totally honest, my HPII probably no longer weighs 10# as = most of the innards have long departed the a/c. =20 The model I purchased was the Gen II - Collector Series, p/n = 1040. It has 3" inlet and 3" outlet, with a 4" dia. body. Total length = is21", body length is 15". Literature says that it is good for 1000 hp, = so it may have a chance of lasting at least 100 hrs on my 3-rotor = running for hours at WOT. We'll have to wait and see on the longevity. = I have a decible meter, so I can take some before and after readings. = Cost was $152 with shipping from Canada. I'm going out to the airport this morning to see how well it = fits. More on how well it fits & works later...=20 Mark S. ------------------------------------------------------------------------ -- Homepage: http://www.flyrotary.com/ Archive and UnSub: = http://mail.lancaironline.net:81/lists/flyrotary/List.html ------------------------------------------------------------------------ No virus found in this incoming message. Checked by AVG - http://www.avg.com=20 Version: 8.0.176 / Virus Database: 270.10.16/1926 - Release = Date: 1/30/2009 5:31 PM -------------------------------------------------------------------------= ----- No virus found in this incoming message. Checked by AVG - http://www.avg.com=20 Version: 8.0.176 / Virus Database: 270.10.16/1929 - Release Date: = 2/1/2009 6:02 PM ------=_NextPart_000_0021_01C98511.F72587E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Mark,
 
the only time sound measurements are = useable is if=20 the conditions are the same every time you measure. You never know = exactly which=20 of the sound is generated by the source and which by secondary = resonators or=20 reflectors.
This should not be discouraging, just = keep the=20 measuring condition as close as possible the same, and you can judge = which way=20 your efforts are going.
 
I my self will be in this situation = hopefully soon.=20
FWIW.
 
Richard Sohn
N2071U
----- Original Message -----
From:=20 Mark = Steitle=20
Sent: Monday, February 02, 2009 = 7:14=20 AM
Subject: [FlyRotary] Re: My New = DNA=20 Muffler

After posting my original message I thought I should = clarify a=20 couple of things about my noise level readings.  These were taken = inside=20 the a/c, but with the door open and the carpet and soundproofing = removed from=20 the floor.  The single gullwing door opens up and would tend = to=20 catch the sound the same as cupping your hands over your ears = does.  The=20 exhaust exits the cowl on the left side, just aft of the firewall=20 and below the door opening.  I was parked on concrete, so = with the=20 muffler pointed back and down at about 45*, the readings were = exaggerated by=20 the sound bouncing off of the concrete.  Hopefully, that = wouldn't=20 happen when flying.  
 
Mark S.

On Sun, Feb 1, 2009 at 9:19 PM, Mark Steitle = <msteitle@gmail.com> = wrote:
Richard,

I think you're right on with = your=20 comment.  I cobbled up the new muffler onto the old manifold = and ran it=20 up to 4000 rpm today.  At 1500-1600, the noise level inside the = a/c was=20 ~89 db, at 4000 it was 102db.  It wasn't any noisier than the = burned=20 out Hushpower II, but it wasn't much quieter either.  = Unfortunately,=20 with the setup I had, I didn't want to run it any harder, but it did = seem to=20 work better the faster I ran the engine.  It wouldn't be any = trouble to=20 neck down the exit from 3" to 2".  More on that = later...

Mark=20 S.
 

On Sat, Jan 31, 2009 at 9:09 AM, Richard = Sohn <res12@fairpoint.net> wrote:
With the inlet and outlet the = same size, I=20 would not be surprised if it does very little noise reduction, if = any.=20 Some tests in the past have shown that a smaller exit makes a = considerable=20 difference in sound level with moderate loss of power. =
FWIW.
 
Richard = Sohn
N2071U
-----=20 Original Message -----
From:=20 Mark Steitle
To:=20 Rotary motors in = aircraft=20
Sent:=20 Saturday, January 31, 2009 8:48 AM
Subject:=20 [FlyRotary] My New DNA Muffler

Hey Guys,

My new DNA muffler arrived = yesterday so=20 I thought I would post a couple of pictures with some = information and=20 first impressions.
 It appears to be very well built, = all tig=20 welded, and no packing to burn out.  It weighs just under = 5#, which=20 is half of what the Hushpower II weighs, so if it works, I will = have=20 reduced my fwf weight by 5#.  To be totally honest, my HPII = probably no longer weighs 10# as most of the innards have long = departed=20 the a/c. 

The model I purchased was the Gen II - = Collector=20 Series, p/n 1040.  It has 3" inlet and 3" outlet, with a 4" = dia.=20 body.  Total length is21", body length is 15".  = Literature=20 says that it is good for 1000 hp, so it may have a chance of = lasting at=20 least 100 hrs on my 3-rotor running for hours at WOT.  = We'll have=20 to wait and see on the longevity.  I have a decible meter, = so I can=20 take some before and after readings.  Cost was $152 with = shipping=20 from Canada.

I'm going out to the airport this morning to = see how=20 well it fits.  More on how well it fits & works = later...=20

Mark S.

--
Homepage:  = http://www.flyrotary.com/
Archive=20 and UnSub:  =20 = http://mail.lancaironline.net:81/lists/flyrotary/List.html


No virus found in this incoming message.
Checked = by AVG -=20 http://www.avg.com
Version: 8.0.176 / Virus Database: = 270.10.16/1926 - Release Date: 1/30/2009 5:31=20 = PM

=


No virus found in this incoming message.
Checked by AVG = -=20 http://www.avg.com
Version: 8.0.176 / Virus Database: = 270.10.16/1929 -=20 Release Date: 2/1/2009 6:02 PM
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