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Mark,
I had a quick look and noticed the parts welded
from the outside - very good I thought. The edges facing down stream will help.
I didn't notice the price, so what price is the Gen 2.
My parts cost me about $250 (Aust) and the welding,
perhaps $150 (Aust)- so if your buying it for about $250 US it's a good
price.
George ( down under)
----- Original Message -----
Sent: Saturday, January 17, 2009 10:51
AM
Subject: [FlyRotary] Re: DNA
Muffler
George,
With the edges of each cross bar pointed
downstream of the exhaust flow, I don't see a problem with the heat attacking
them. Also, if one were to somehow break loose, I don't see how it could
manage to block the exit, maybe partially, but not totally. The engine
should still run at reduced power if that were to happen. I would like
to special order one made of 321ss. Also, if you look at the DNA web
site, you'll see that they make a Gen 1 and a Gen II. The Gen II is much
stronger as the cross bars protrude through the can and are welded from the
outside. The Gen I bars are spot welded to the can. The Gen II is
also more than twice the price of the Gen I.
Mark S.
On Fri, Jan 16, 2009 at 4:10 PM, George Lendich <lendich@optusnet.com.au>
wrote:
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.
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