X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-3.exch003intermedia.net ([207.5.74.110] verified) by logan.com (CommuniGate Pro SMTP 5.2.13) with ESMTPS id 3543749 for flyrotary@lancaironline.net; Wed, 11 Mar 2009 11:58:28 -0400 Received-SPF: none receiver=logan.com; client-ip=207.5.74.110; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-3.exch003intermedia.net ([207.5.74.110]) with mapi; Wed, 11 Mar 2009 08:57:21 -0700 From: Jeff Whaley To: Rotary motors in aircraft Date: Wed, 11 Mar 2009 08:57:49 -0700 Subject: RE: [FlyRotary] Re: DNA Muffler Thread-Topic: [FlyRotary] Re: DNA Muffler Thread-Index: AcmiXeBOVaYZ8dniQjC9c8qdr+y24gAAxaDA Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_C03ABB0A7362B84BB53D544B3C305E0ED149457A26EXVMBX0035exc_" MIME-Version: 1.0 --_000_C03ABB0A7362B84BB53D544B3C305E0ED149457A26EXVMBX0035exc_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable I should have said "Hush Power II weight is significant" can't remember wha= t it weighed ... was hoping the DNA weighed considerably less ... guess not= . I'm interested in the tapered outlet as well. Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Tracy Crook Sent: Wednesday, March 11, 2009 11:26 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: DNA Muffler Hmm... I weighed my HushPower II at 8 lbs (with guts :-) I assume at this point (300+ hrs) that mine has lost the fiber packing bu= t the internal baffles are still there. Anxious now to try the outlet neck= down to see if it has as much effect on the HP II as Mark's did on the DNA= . Tracy On Wed, Mar 11, 2009 at 8:22 AM, Jeff Whaley > wrote: Hi Mark, I was just at the DNA website ... they don't specify weight for an= y of their products. The Hush Power II is about 20 lbs. What is the weight of your DNA-1040, Full Throttle Collector? Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mike Wills Sent: Tuesday, March 10, 2009 10:36 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: DNA Muffler Agreed Mark. Was just looking for some feedback on that aspect since your f= irst email focused on the durability side. Thanks for the info and keep us = posted. If it holds up I'll give it a try. Mike ----- Original Message ----- From: Mark Steitle To: Rotary motors in aircraft Sent: Tuesday, March 10, 2009 5:57 AM Subject: [Norton AntiSpam] [FlyRotary] Re: DNA Muffler 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 puddl= e 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 l= ouder than an IO-540 powered Lancair, or so I'm told. When I first installed the DNA "Full Throttle Collector" (DNA p/n 1040) muf= fler I was disappointed in its poor muffling qualities. It was about as lo= ud as the gutted HP II, but at a lower tone and with a very high-pitched as= pect 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 red= ucer 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 notic= ably 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 ha= ngar neighbors. Early on I used to get lots of "friendly" comments about h= ow they could hear me coming long before they could see me. Now, those com= ments have stopped. They still ask about that "strange sounding" engine, b= ut 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 m= easurements 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 disappoint= ed. I know its hard to judge but how about your opinion regarding the volum= e? 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 p= lace 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 powe= r 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 min= d 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 ha= d 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 ex= haust noise to an acceptable level. (Maybe I should have just put the redu= cer on the 3" downpipe and saved some weight.) Anyway, when it passes 25 h= ours, 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 G= en II muffler (http://www.dnamufflers.com/DNA/main_DNA.html)? It is an int= eresting design in that it has no packing material to burn out. Instead, i= t 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 gre= at success. From speaking with a sales rep, they claim there the rotary cr= owd uses them too. I'm considering purchasing one of their FULL THROTTLE C= OLLECTOR mufflers (P/N 1040), but thought I would check to see if anyone el= se 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. --_000_C03ABB0A7362B84BB53D544B3C305E0ED149457A26EXVMBX0035exc_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

I should have said “Hush Power II weight is significan= t” can’t remember what it weighed … was hoping the DNA weighed considerably less … guess not.

I’m interested in the tapered outlet as well.

Jeff

 

From: Rotary motors= in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Tracy Cro= ok
Sent: Wednesday, March 11, 2009 11:26 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: DNA Muffler

 

Hmm... I weighed my Hus= hPower II at 8 lbs (with guts :-) 
 I assume at this point (300+ hrs)  that mine has lost the fiber packing but the internal baffles are still there.  Anxious now to try = the outlet neck down to see if it has as much effect on the HP II as Mark's did= on the DNA.

Tracy

On Wed, Mar 11, 2009 at 8:22 AM, Jeff Whaley <jwhaley@datacast.com> wrote:

Hi Mark, I was just at th= e DNA website … they don’t specify weight for any of their products.<= /span>

The Hush Power II is abou= t 20 lbs.

What is the weight of you= r DNA-1040, Full Throttle Collector?

Jeff

 <= /p>

From: Rotary motors in aircraft [mailto:flyrotary@lan= caironline.net] On Behalf Of Mike Wills
Sent: Tuesday, March 10, 2009 10:36 PM


To: Rotary motors in aircraft

Subject: [FlyRotary] Re: DNA Muffler

 

Agreed Mark. Was just looking for some = feedback on that aspect since your first email focused on the durability side. Thank= s for the info and keep us posted. If it holds up I'll give it a try.<= o:p>

 

Mike

----- Original Message -----

From: Mark Steitle

Sent: Tuesday, March 10, 2009 5:57 AM

Subject: [Norton AntiSpam] [FlyRotary] Re: DNA Muffler

 

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 lo= wer 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 h= ow 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 g= et 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.  The= y still ask about that "strange sounding" engine, but only because = it sounds different, not because it is loud enough to break windows for m= iles around.  I'll try to remember to take some sound level measurements ne= xt time I'm out at the airport.  

 

Mark S.    

On Mon, Mar 9, 2009 at 10:50 PM, Mike Wills <rv-4mike@cox.net>= wrote:

Well, the other big question is does it actually muffle? If the best thing that can be said about it is that i= t's surviving I'd be a little disappointed. I know its hard to judge but how ab= out your opinion regarding the volume?

 

Thanks,

 

Mike Wills

----- Original Message -----

From: Tracy Crook

Sent: Monday, March 09, 2009 8:38 AM

Subject: [FlyRotary] Re: DNA Muffler

 

"sounds good" Mark.  My gu= ess 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 <msteitle@gmail.com= > 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 ma= de 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 ou= tlet in order for it to be acceptable in the noise category, but that was&n= bsp;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 a= nother update.  At this time it is looking very promising.

 

Mark S.

On Sun, Mar 8, 2009 at 9:20 PM, Mike Wills <rv-4mike@cox.net>= wrote:

Mark,

 

 Any update on the DNA muffler?

 

Mike Wills

RV-4 N144MW

----- Original Message -----

From: Mark Steitle

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 (htt= p://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 "interna= l 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 wit= h 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 s= tyle 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.

 

 

 

 

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