WRJJRS@aol.com wrote:

Kevin,

With rotaries they have found that a constantly expanding exhaust helps keep the pulse moving. It also keeps the LOUD moving. The Rotary will tolerate some back pressure, but since there is no exhaust valve it helps to be sure that there are as few reflecting surfaces as possible until the port is closing.

Bill Jepson

Okay,  This brings to mind a question: how fast are those pulse moving?
It's pretty easy to figure out how long between pulses for any given
RPM, but it would be nice to know how far down the pipe a puff of
exhaust gets before the next one starts chasing it.  Anyone here already
know this?  (Yes, I know I can search for it on the net - well, this is my
first attempt.)

Best Regards,
Dale R.
COZY MkIV #1254