Paul wrote:

IMHO you guys are going to find it hard to beat a simple tangential
muffler in terms of  noise reduction to weight ratio. Number one it requires
no internal baffles or packing. The exhaust pulses just twirl around in there
until they are homogenized.

Finn Lassen wrote:

>From my limited experience, I agree. My home made 4"x6"x12" oval muffler, fed by
2"D, 3" long straight header pipes, and 2" exhaust pipe diagonally through it,
reduced exhaust noise so well that it was barely noticeable over prop noise. I could
probably have made it work by bellows or flex pipe in the header and exhaust pipes
to avoid cracking. However, I was very uncomfortable with all the heat under the
cowling and necessary heatshields around it (which made regular inspections for
cracks very difficult).

Finn

 
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