Alan, thanks for the invaluable information. Any information from your and
Everett's work is welcomed. I talked with Everett a couple of times on the
phone. Sorry I never got to meet him in person.

I just received my Flowmaster  Hushmaster Muffler yesterday. It's the same
that Tracy is currently using. It's made out of 304 stainless, and appears to
have a cone of perforated metal at the inlet
and outlet. If it's not quiet enough, I'll construct a "Swiss" muffler to
stick on the end of that.  A Swiss muffler is described in Tony Bingelis's
book "Firewall Forward".The exhaust system one
area on the rotary that deserves the best design possible, so your experience
is most welcome here.

Brian Trubee

I suspect the reason turbo charged engines have lower BSFC is because of
the intercooler. The intercooler represents a loss of over all heat.
It takes HP to compress the air despite the fact most of it is coming
from the waste heat in the exhaust. There is some back pressure associated
with turbo chargers. Part of the energy stored in the compressed
air is in the form of heat. If you throw that away in an intercooler
you are losing some energy from the gallon of gas. The answer is to extract
as much energy out of the exhaust as possible in the form of turbo compounding.

Here is a heat balance chart for a RR Merlin aircraft engine. 2.5% is needed to
operate the supercharger.

Paul Lamar

Paul

Thanks for your thoughts on turbo charging and energy loss through the
intercooler. I'm not sure I follow you however.  The intercooler losses heat
from a net energy gained through turbo charging.  In any case I heard today
my turbocharging book by Hugh Mc'G. is in the mail from the states.  I'll
read it and learn.

What exhaust system would be the best for mounting the turbine for the turbo
compound on the Renesis?

A design with little restriction and drag on the gas velocities I suppose.

I was thinking a Jerry's spin design with a cockpit heating pipe through the
middle and possible baffles to direct the exhaust gases to the outlet on the
top pipe middle. I was thinking 3" or 4"ID  inconel with a 1 1/4 through
pipe. The three individual exhaust  pipes come straight out and are shaped
and welded to the fit the main pipe contour on top.  Exhaust gases come
straight out entering at a tangent and spin 180 degrees  down and around the
central heater pipe and up towards the central outlet.  Inconel pipe is heat
shielded outside. Turbine has cool water jacket.

Your thoughts?

Thanks

Doug in Japan

Well yes it does but don't forget BSFC is related to power out.
Power is up but so is fuel consumption even more. BSFC is the ratio.

I am not sure I follow you on the exhaust system. What type of turbo
compound system are you proposing?

Paul Lamar
 
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