Paul,
 I am really glad you were able to run the muffler. To be honest 
I'm not supprised that the muffler was loud without the tailpipe. 
In fact I am supprised you didn't see more reversal of exhaust gasses 
without the momentum of gas in the tail pipe. Draw in the center tube 
could be checked with a cigarette (smoke) in front of the tube. Would 
be interesting. Obviously the engine exit tubes could have a slight 
bend to lower the muffler for firewall clearance. That might just 
be on tracy's test set up, you were there after all!  Many thanks 
are due Ed for making the test sample so fast. Fun stuff.
Thanks to all newsletter contributors, especially Paul for 
keeping it all going! Bill Jepson

There is not a lot of draw but the front can be fed with a blast tube
and dynamic pressure. 

BTW a subtle advantage of this muffler design is the fact the exhaust
gases are cooled. That is very very important for people with
pusher aircraft that must feed the exhaust through the prop.

In a direct drive AC engine you can clock the prop to miss the exhaust pulses.
That is not possible with a non integer PSRU reduction ratio. Every so often
the prop blade is right in the path of the exhaust pulse.

Paul Lamar
 
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