X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from qw-out-2122.google.com ([74.125.92.24] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTP id 3541879 for flyrotary@lancaironline.net; Tue, 10 Mar 2009 08:58:00 -0400 Received-SPF: pass receiver=logan.com; client-ip=74.125.92.24; envelope-from=msteitle@gmail.com Received: by qw-out-2122.google.com with SMTP id 8so1053107qwh.25 for ; Tue, 10 Mar 2009 05:57:23 -0700 (PDT) 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=fMKViAuLAG2GXfjxltZJhpVeWOmp7PtKdJlRObXfqpc=; b=Vi92bATcHTqAy6XO2iCz4fGe5PAgX3jJqBwUgqfcR2IwpCNlrOy3SavNpgRyVrT3Ar SPhR3miVyoynLWI4RKHe+DjnnHSESaqupZ9DSF3lzhvm2fo6ptpjdQRgE7M/xrlGSWnp e2+a6sxQ4VbXMRh/9HJjir4kzsWYd8puzoIbM= 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=hvrU0YRRR21a1LEFYGJVOLVAI6JaL5nKYr9UEKSOZ4OmT5lPPHXUhzADS/vPjfHyjw fd58cWjJAFEEcxjiG0VRnKOLJcHPoBGWLzUgunn+t6IVILeOKwjkrdcb/jOjc/VKSz9m e1VB3qwTuCkIUlESHxtfYNcr4U/DHuZYpwMsw= MIME-Version: 1.0 Received: by 10.224.45.193 with SMTP id g1mr9130268qaf.247.1236689843500; Tue, 10 Mar 2009 05:57:23 -0700 (PDT) In-Reply-To: References: Date: Tue, 10 Mar 2009 07:57:23 -0500 Message-ID: <5cf132c0903100557s3d6a6171lb00e13f8b78d65d0@mail.gmail.com> Subject: Re: [FlyRotary] Re: DNA Muffler From: Mark Steitle To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0015175cb02cd1b79f0464c34a15 --0015175cb02cd1b79f0464c34a15 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit That's true Mike, but the opposite is also true. If it muffles but doesn't last, it still fails the test. That was the case with the HushPower II. It muffled great for about 30 minutes, then the guts oozed out into a puddle on the hangar floor. As for muffling, well, let's just say that you won't be the stealthiest a/c of the group. But then my 20B Lancair isn't any louder than an IO-540 powered Lancair, or so I'm told. When I first installed the DNA "Full Throttle Collector" (DNA p/n 1040) muffler I was disappointed in its poor muffling qualities. It was about as loud as the gutted HP II, but at a lower tone and with a very high-pitched aspect that my Lightspeed ANR headset couldn't cancel out. Then I remembered what Tracy said about large diameter exhaust pipes (the DNA muffler that I chose has a 3" inlet & 3" outlet). So, I purchased a 3" to 2" tapered reducer from Burns Stainless and welded it onto the outlet. It is surprising how much difference that one small change made in reducing the noise level. The high-pitched aspect was now gone and the lower frequencies were noticably reduced. If there was any loss of power I couldn't tell it. So, out of the box the DNA is too loud, but with a slight modification, it is very acceptable. My main guage for acceptable exhaust noise is the comments I get from my hangar neighbors. Early on I used to get lots of "friendly" comments about how they could hear me coming long before they could see me. Now, those comments have stopped. They still ask about that "strange sounding" engine, but only because it sounds different, not because it is loud enough to break windows for miles around. I'll try to remember to take some sound level measurements next time I'm out at the airport. Mark S. On Mon, Mar 9, 2009 at 10:50 PM, Mike Wills wrote: > Well, the other big question is does it actually muffle? If the best > thing that can be said about it is that it's surviving I'd be a little > disappointed. I know its hard to judge but how about your opinion regarding > the volume? > > Thanks, > > Mike Wills > > ----- Original Message ----- > *From:* Tracy Crook > *To:* Rotary motors in aircraft > *Sent:* Monday, March 09, 2009 8:38 AM > *Subject:* [FlyRotary] Re: DNA Muffler > > "sounds good" Mark. My guess is that the 2" restrictor is in the correct > place now. Don't think it would be as effective before the muffler. > > But the big question is, did the 3 to 2 " reducer cause any noticeable > power loss? I plan to do the same thing on my plane when time allows. > > Tracy > > On Mon, Mar 9, 2009 at 8:08 AM, Mark Steitle wrote: > >> Mike, >> >> It may be a little premature to declare it a winner, but with ~10 hrs on >> it now, it is holding up better than anything I've tried so far. Keep in >> mind that this is DNA's best muffler, rated for 1000hp. It is made of >> fairly thick SS, .030 if I recall, much thicker material than most >> mufflers. I had to add a 3" to 2" taper to the outlet in order for it to be >> acceptable in the noise category, but that was surprisingly effective in >> reducing the exhaust noise to an acceptable level. (Maybe I should have >> just put the reducer on the 3" downpipe and saved some weight.) Anyway, >> when it passes 25 hours, I'll post another update. At this time it is >> looking very promising. >> >> Mark S. >> >> On Sun, Mar 8, 2009 at 9:20 PM, Mike Wills wrote: >> >>> Mark, >>> >>> Any update on the DNA muffler? >>> >>> Mike Wills >>> RV-4 N144MW >>> >>> ----- Original Message ----- >>> *From:* Mark Steitle >>> *To:* Rotary motors in aircraft >>> *Sent:* Friday, January 16, 2009 7:05 AM >>> *Subject:* [FlyRotary] DNA Muffler >>> >>> Does anyone on the list have any real-life rotary experience with the DNA >>> Gen II muffler (http://www.dnamufflers.com/DNA/main_DNA.html)? >>> It is an interesting design in that it has no packing material to burn out. >>> Instead, it utilizes ladder-rungs, which they call "internal sound >>> diffusers", which resemble a chain of DNA down through the center of the >>> muffler body, which is made of 304 SS. Their web site claims that the >>> racers use them with great success. From speaking with a sales rep, they >>> claim there the rotary crowd uses them too. I'm considering purchasing one >>> of their FULL THROTTLE COLLECTOR mufflers (P/N 1040), but thought I would >>> check to see if anyone else has used this style muffler. This muffler has a >>> 3" inlet/outlet with a 4" body. So it is compact enough to fit inside my >>> cowl. My exhaust header has a 3" swivel joint, so it should be a good fit. >>> >>> >>> Mark S. >>> >>> >> > --0015175cb02cd1b79f0464c34a15 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
That's true Mike, but the opposite is also true.=A0 If it muffles = but doesn't last, it still fails the test.=A0 That was the case with th= e HushPower II.=A0=A0It muffled great for about 30 minutes, then the guts= =A0oozed out=A0into a puddle on the=A0hangar floor. =A0As for=A0muffling, w= ell, let's just say that you won't be the stealthiest a/c of the gr= oup.=A0=A0But=A0then my 20B Lancair isn't any louder than an IO-540 pow= ered Lancair, or so I'm told.=A0=A0
=A0
When I first installed=A0the DNA "Full Throttle Collector" (= DNA p/n 1040) muffler=A0I was disappointed in=A0its poor muffling qualities= .=A0 It was about as loud as the gutted HP II, but at=A0a lower tone and wi= th a very high-pitched aspect that=A0my Lightspeed=A0ANR headset couldn'= ;t cancel out.=A0 Then I remembered what Tracy said about=A0large diameter = exhaust=A0pipes (the DNA muffler that I chose has a=A03" inlet & 3= " outlet).=A0 So, I purchased a=A03" to 2"=A0tapered reducer= =A0from Burns Stainless=A0and welded it onto the outlet.=A0=A0It is surpris= ing how much difference that one small change made in reducing the=A0noise = level.=A0 The high-pitched aspect was now gone and the lower frequencies we= re=A0noticably reduced.=A0=A0If there was=A0any loss of power I couldn'= t tell it.=A0 So, out of the box the DNA is too loud, but with a slight mod= ification, it is very acceptable.=A0
=A0
My=A0main guage for acceptable exhaust noise is=A0the comments I get f= rom my hangar neighbors.=A0 Early on I used to get lots of "friendly&q= uot; comments about how=A0they could hear me coming long before they could = see me.=A0 Now, those comments have stopped.=A0 They still ask about that &= quot;strange sounding" engine, but only because it sounds different, n= ot because it is=A0loud enough to break windows for miles around.=A0 I'= ll try to remember to take some sound level measurements next time I'm = out at the airport.=A0=A0
=A0
Mark S.=A0=A0=A0=A0

On Mon, Mar 9, 2009 at 10:50 PM, Mike Wills <rv-4mike@cox.net&= gt; wrote:
Well, the other big question is does i= t actually muffle? If the=A0best thing that can be said about it is that it= 's surviving I'd be a little disappointed. I know its hard to judge= but how about your opinion regarding the volume?
=A0
Thanks,
=A0
Mike Wills
----- Original Message -----
Sent: Monday, March 09, 2009 8:38 AM=
Subject: [FlyRotary] Re: DNA Muffler=

"sounds good" Mark.=A0 My guess is that the 2"= ; restrictor is in the correct place now.=A0 Don't think it would be as= effective before the muffler.

But the big question is, did the 3 to= 2 " reducer cause any noticeable power loss?=A0=A0 I plan to do the s= ame thing on my plane when time allows.

Tracy

On Mon, Mar 9, 2009 at 8:08 AM, Mark Steitle <= msteitle@gmail.com> wrote:
Mike,
=A0
It may be a little premature to declare it a winner, but with ~10 hrs = on it now, it is holding up better than anything I've tried so far.=A0 = Keep in mind that this is DNA's=A0best muffler, rated for 1000hp.=A0 It= is made of fairly thick SS, .030 if I recall, much thicker material than= =A0most mufflers.=A0 I had to add a 3" to 2"=A0taper=A0to the out= let in order for it to be acceptable in the noise category, but that=A0was= =A0surprisingly effective=A0in reducing the exhaust noise to an acceptable = level.=A0 (Maybe I should have just=A0put the reducer on the 3" downpi= pe and saved some weight.)=A0 Anyway, when it passes 25 hours, I'll pos= t=A0another update.=A0 At this time it is looking very promising.
=A0
Mark S.

On Sun, Mar 8, 2009 at 9:20 PM, Mike Wills <rv-4= mike@cox.net> wrote:
Mark,
=A0
=A0Any update on the DNA muffler?
=A0
Mike Wills
RV-4 N144MW
----- Original Message -----
From: Mark Steitle
To: Rotary motors in aircraft
Sent: Friday, January 16, 2009 7:05 AM
Subject: [FlyRotary] DNA Muffler

Does anyone on the list=A0have any=A0real-life rotary experience with= =A0the DNA Gen II muffler (http://www.dnamufflers.com/DNA/main_DNA.html= )?=A0 It is a= n interesting design in that it has no packing material to burn out.=A0 Ins= tead, it utilizes ladder-rungs, which they call "internal sound diffus= ers",=A0which resemble a chain of DNA down through the center of the m= uffler body, which is made of 304 SS.=A0 Their web site claims that the rac= ers use them with great success.=A0 From speaking with a sales rep, they cl= aim there the rotary crowd uses them too.=A0 I'm considering purchasing= one of their FULL THROTTLE COLLECTOR mufflers (P/N 1040), but thought I wo= uld check=A0to see if anyone else has used this style muffler.=A0 This muff= ler has a 3" inlet/outlet with a 4" body.=A0 So it is compact eno= ugh to fit inside=A0my cowl.=A0 My exhaust header has a 3" swivel join= t, so it should be a good fit.=A0
=A0
Mark S.



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