Those Burns Stainless mufflers are just what we are looking for.
a 2 1/2" inlet is 3 1/2" in diameter and 17.1 inches long and
weighs just
2.7 pounds. Cost $216.75. What a bargain. I don't know the SS
alloy but it could be 321. I'll bet they will make them
in Inconel if you ask as they are now selling Inconel
tubing.
www.burnsstainless.com
Paul Lamar ...No rotor no motor.
Be careful, the prices listed are for soft packing. The stainless steel
scrubble option adds approx. $25 or so from Burns. I would recommend
the 4.5" OD for better sound attenuation and packing heat tolerance for
a very minimum weight gain. For that particular size you will get a
better price from Pegasus Racing and I believe they include scrubble
packing, under $200. I believe the standard alloy is T304. Burns is
not the original supplier and they charge significantly for custom
work. Some people questioned using them on the rotary. So far I
haven't had an issue BUT the mufflers in my application are much further
downstream from the engine than they would be for an aircraft. They are
repackable. I believe Coast Fabrication is the company where these are
built. Unfortunately they seem to have the highest retail price, but
they do offer customization service for the mufflers:
http://www.coastfab.com/ultralights.html
The exit connection is a bit tricky if you plan to weld an outlet
pipe/tip to it. The muffler outlet was originally intended to be the
exhaust exit. All it is is a straight-thru perforated tube core with an
outer housing that is held on by several small screws and the packing
filled in the void. On the exit the core tube slips through and extends
out of the end cap slightly like a slip joint. The core tube OD is the
same as the muffler ID listing, in this case 2.5". In order to weld a
pipe or tip to the muffler you will need an expanded slip-type joint to
slip over the core tube extension and weld to the outer housing end
cap. You will need to leave a sizeable length of slip joint from the
end of the core tube for it to expand within if you want to have the
exit pipe be the same size as the outlet. The core tube will expand and
lengthen a considerable amount under max temperature conditions. If you
don't leave enough room in the exit slip joint connection the core
will lengthen to the point of binding up and twisting itself into a
pretzel inside the canister. I have seen it happen. The easier
alternative is to just step up to the next larger tubing size for the
muffler outlet. To achieve the low weight everything is very light guage.
I have several here at the moment and will try to take a few pictures
later today to better explain the details for you.
Mark Sipe
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