This triggered an idea in my brain. Why not use an exhaust
ejector to add air mass and kinetic energy to the exhaust gas and  cool it
off at the same time? This might be very valuable with a turbo  compound
set up. The ejector could be curved for packaging reasons. Would  also work
for turbo charging of course. The cooling air supply would be  connected
to a ram air scoop behind the prop to get an unlimited supply of  cool air.
This could be a very significant break through in turbo compounding  the
rotary.

Patent pending :)

Paul Lamar ...No rotor no motor.

If used in a non-turbo environment, what implications would an ejector
like this have on noise levels?

Steve

They have been used and they do reduce the noise. When combined
with a fish tail as in this 2nd dwg they would work even better.