Bill Jepson wrote:

Paul, The attached jpeg is a variation on the tangental muffler theme.
The intent is to cool the exhaust system using the exhaust energy. A
outside air source is provided near the front. The design could also

be

inverted, (exhaust inside the the can), if the inside tube wouldn't
provide enough cooling. The tail pipe mixing should also make it a bit
quieter.  comments? Bill Jepson

That is a really great idea Bill. I really like it. I think it is
THE soluttion.

Al Gietzen wrote:

What am I missing here?  It seems quite apparent that the exhaust will
come out both ends.  The pressure at the 'back' end of the inner tube
will be quite high.

Al

It depends on the area ratio of the concentric space to that of the tail
pipe area. It should work like a thrust augmentor. There may be a slight
design change required to get a venturi shape around the cooling pipe
exit.

Dynamic pressure could also be fed in at the front to enhance the flow.

Paul Lamar

Paul,
Pressure is the answer for an augmentor, in flight pressure with the opening
to the free air stream should provide sufficient pressure, also (and I'm not
sure here) would a trumpet ( bell shape) exhaust gas exit,  help with the
extraction.
I know if you put a pressure tube ( compressor air line) inside a tube with
a trumpet (bell) shaped face it gives good suction. What I don't know is if
the suction ( vacuum) is proportional to pressure of the inside tube -I'm
guessing it is.

In a tractor application, the prop should provide sufficient pressure for
low RPM - I'm unsure on a pusher!
George (down under)

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