Mark, I have read your description of how to build the tuned
tangential a couple of times and I still don't have any idea of how
to build it. That is my problem, not a reflection on your writing.
The eight to ten inch final diameter is going to be hard to live
with. I can say with confidence that you will not be able to get it
inside the S-beam engine mount. I have fit several six inch simple
tangential inside S-Beam engine mounts and there is not room for
anything larger. Also, the larger diameter would place the muffler
unacceptably close to the intake or drive it very low where it will
invade the radiator's space. The options are down to one, I'm sorry
to say, and that is the simple tangential, max diameter 6 inches and
maximum length 8.5 inches. The ones I built were 10 inches long, but
with the relocated S-beam, the muffler has had to be shortened a bit.
On the positive side, Bob Whites initial reports indicate that the
muffler may be satisfactory as far as noise suppression is
concerned. Once he goes to WOT, we will know more. Also, my muffler
which is a zero back pressure design, may deliver more power than
some of the more restrictive designs. We will soon have some real
data on h.p too. In particular I am looking forward to how Mark's p-
port breaths at 8500 rpm. The muffler/exhaust system was conceived
with the p port in mind. I got my fingers crossed...
BTW, I think the Renesis side port exhaust sucks because it
doesn't. Jerry
The center-center dimension between the Renesis end ports is 10.5" so if
your main canister is limited to 8.5" long you have some creative piping
to consider. Perhaps centering the main canister to the center port
with the end ports coming in at an angle yet still tangential is an
option. Paul included a 3D layout earlier in the discussion where the
front end port elbowed into the end of the collector canister. That may
be an option for you too. Perhaps Paul can provide further guidance on
this as I am new to the tangential design. I find it intriguing and
possibly having potential for some non-aviation uses.
Some of the systems I've described are really more of a tangential
header manifold than a muffler. I'm contemplating designs for a Mazda
RX-8 race system which will include piping toward the rear of the car
fitted with several stainless scrubble-packed lightweight racing
mufflers available from Burns Stainless etc.. The car will still be
quite loud even with these, though not nearly as much as most aviation
applications. In a few event locations there are specific sound
controls that must be adhered to so any additional damping that can be
provided at the exhaust manifold is welcomed, but not paramount for my
intended application.
Mark Sipe
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