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From: "Al Gietzen" <ALVentures@cox.net>
To: "'Rotary motors in aircraft'" <flyrotary@lancaironline.net>
Subject: RE: [FlyRotary] Muffler
Date: Mon, 9 Jun 2008 21:58:50 -0800
Message-ID: <000001c8cabf$0e809050$6401a8c0@BigAl>
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Neil;

Is the muffler SS?  Do you plan to support the muffler in some way in
addition to the header pipes?  That configuration is similar to a =
tangential
muffler that Dave Atkins did first time around on his plane.  It didn't =
take
very long for the muffler to fall apart - stress corrosion.  I don't =
know
what wall thickness he used.

Also; do you expect to support that exit pipe in some way?  Another guy =
on
this list (can't recall his name, but he's in Oregon) had a tangential
muffler with a cantilevered exit pipe, and it failed twice in a =
relatively
short time.  I'm guessing due to vibrational stress.

Not trying to be an alarmist - Just something to consider.

Al G


To all,

	Here are a few shots of the muffler Jim and I constructed for the
Volmer.  You may notice that the inlet pipes are not in the middle of =
the 6"
tube but a little higher up.  The thought was to swirl the gasses inside =
the
big pipe before exiting through the little pipe.  Not sure if that will =
make
any major difference.  Also, it drops the whole muffler down and away =
from
the intake manifold a little bit.

	The one end of the little pipe was welded to the inside of the end
cap before the end cap was welded to the 6" pipe.  Time will tell how =
this
version holds up.

Neil=20

Everybody likes pictures... =20


-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On
Behalf Of Al Wick
Sent: Monday, June 09, 2008 10:15 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: Mistral Crash Analysis

> So, Al, why don't you post a sketch/drawing of your muffler design and =

> give us some details - dimensions/materials etc.  You design may be =
the=20
> answer someone has been looking for.

My muffler had two desireable features.
1) Having two outlets means it can't get plugged up like the mistral. So =

that really increases your safety margin.
2) It wasn't welded in place. The inlets were slip fit to the header. =
That=20
worked real well. Although towards the end of the 230 hours, I was =
starting=20
to see wear of the mild steel. The slip fit eliminates all the forces =
from=20
the two headers expanding and contracting.

I don't think my design had any redeeming value otherwise. It was pretty =

cheesy design.... a flat plate of ss wedged inside the canister. The SS =
had=20
holes drilled in it of various sizes. Neils muffler way more robust. =
BTW, I=20
call it "my design" but most of it based on a text discription from =
another=20
builder.

-al wick=20

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