Mailing List flyrotary@lancaironline.net Message #44760
From: George Lendich <lendich@optusnet.com.au>
Subject: Re: [FlyRotary] Re: DNA Muffler
Date: Sat, 17 Jan 2009 08:10:30 +1000
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
Mark,
The heat and pulses attack/ affect the weakest part of any internal part, a thin edge is the weakest part. You will notice that I don't expose and edges to the sound wave or hot gases.
George ( down under)
Ed,
 
That is exactly what I was concerned about too.  But if you look closely, you can see that the bars are made of 90* angle.  That should make them much stronger than straight bar stock.  Not sure what material the cross bars are made from though.  The p/n 1040 is made to weld to a header/collector and they claim it is good for up to 1000hp.    
 
I have gone ahead and ordered one.  I figure it couldn't be any louder than the Hushpower II whose guts are laying on the hangar floor in a pile of powder and small pieces.  Based on its short lifespan and the rust-colored debris, I doubt the Hushpower muffler's innards are made of SS.  ;-(
 
Mark

On Fri, Jan 16, 2009 at 10:08 AM, Ed Anderson <eanderson@carolina.rr.com> wrote:

Appears somewhat similar in concept to the SpinTech muffler using baffles/ladders to break up the sound wave front.  The thing I would wonder about is whether those ladders which appears to stretch across the diameter of the tube could withstand the pulse pounding from the rotor.  My experience with the turbo 13B (with no exhaust splitters) would indicate it might not long withstand that pounding.  But, I could be wrong about that.

 

Guess you're going to have to buy one and let the rest of us know, Mark.

 

Ed

 


From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Friday, January 16, 2009 9:05 AM
To: Rotary motors in aircraft
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.



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