X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-qy0-f17.google.com ([209.85.221.17] verified) by logan.com (CommuniGate Pro SMTP 5.2.12) with ESMTP id 3472167 for flyrotary@lancaironline.net; Mon, 02 Feb 2009 08:15:18 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.221.17; envelope-from=msteitle@gmail.com Received: by qyk10 with SMTP id 10so2765279qyk.19 for ; Mon, 02 Feb 2009 05:14:41 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=m43vh3DUEJwwsN7iYUvJJAMBGlln6KF45sOUtCrAntM=; b=X+WxWbmTkgcleQc8miK3ZNOFGwjLdvRBa+osUsYpdgRZUr7Q2xY/EGPo6OP8cw2tVj rom5ZEPAyfWxYklJR5Rih3oJTETofI7Q9p5G1OKh54SkW4o0TXG6SiMYaX4zc+AQWFG8 IjOXvyu5ybBdfjyNg8jkAwlnW8sXxbHN0jLFQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=BSNpQW6L2GEAaHYeMN9G38uwtxwI+y/VjgnHK8YCbPNsaluox47uMLu0AfkmjBc7w+ RLkHqUV4mGPIe7eiDpfh5k83OhaJin27m331/jeRlevPBRHG3+jhBYGgoSv+a2Wimeme yhLDPew6d7BOqP6EUzZJkahizZvNtMFQo4w+A= MIME-Version: 1.0 Received: by 10.214.116.18 with SMTP id o18mr5672103qac.5.1233580479858; Mon, 02 Feb 2009 05:14:39 -0800 (PST) In-Reply-To: References: Date: Mon, 2 Feb 2009 07:14:39 -0600 Message-ID: <5cf132c0902020514w6f229e4bpb17af307edad8675@mail.gmail.com> Subject: Re: [FlyRotary] Re: My New DNA Muffler From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015175cb54c4dc8350461ef5610 --0015175cb54c4dc8350461ef5610 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit 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. Mark S. On Sun, Feb 1, 2009 at 9:19 PM, Mark Steitle wrote: > Richard, > > 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. > > > 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. >> FWIW. >> >> Richard Sohn >> N2071U >> >> ----- Original Message ----- >> *From:* Mark Steitle >> *To:* Rotary motors in aircraft >> *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. >> >> 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... >> >> 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 >> Version: 8.0.176 / Virus Database: 270.10.16/1926 - Release Date: >> 1/30/2009 5:31 PM >> >> > --0015175cb54c4dc8350461ef5610 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
After posting my original message I thought I should clarify= a couple of things about my noise level readings.  These were taken i= nside the a/c, but with the door open and the carpet and soundproofing remo= ved 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 firewal= l and below the door opening.  I was parked on concrete, so with = the muffler pointed back and down at about 45*, the readings were exaggerat= ed by the sound bouncing off of the concrete.  Hopefully, that wo= uldn't 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 you= r 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 th= e burned out Hushpower II, but it wasn't much quieter either.  Unf= ortunately, with the setup I had, I didn't want to run it any harder, b= ut it did seem to work better the faster I ran the engine.  It wouldn&= #39;t be any trouble to neck down the exit from 3" to 2".  M= ore on that later...

Mark S.
 

On Sat, Jan 31, 2009 at 9:09 AM, Richard Sohn <res12@fairpoint.net> wrote:
With the inlet and outlet the same siz= e, 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.
FWIW.
 
Richard Sohn
N2071U
----- Original Message -----
Sent: Saturday, January 31, 2009 8:48 AM
Subject: [FlyRotary] My New DNA Muffler

Hey Guys,

My new DNA muffler arrived yesterday so I t= hought I would post a couple of pictures with some information and first im= pressions.
 It appears to be very well built, all tig welded, and n= o 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# a= s most of the innards have long departed the a/c. 

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 tha= t it is good for 1000 hp, so it may have a chance of lasting at least 100 h= rs 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 bef= ore 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.&= nbsp; More on how well it fits & works later...

Mark S.

--
Homepage:  http://www.flyrotary.com/
Archive an= d UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/Li= st.html


No virus found in this incoming message.
Checked by AVG - = http://www.avg.com
Version: 8.0.176 / Virus Database: 270.10.16/192= 6 - Release Date: 1/30/2009 5:31 PM


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