Mike Pienaar wrote:
Paul,
Could we ask Brian Perry to expand on what he would put into this big
box that he recommends. Would be good to hear from somebody that works
with it every day.
Mike Wills wrote:
For many of us, a bigger issue is where do you put a 780 cubic inch (or
larger) muffler and how heavy is it? If made of Inconel it can probably be
made fairly light but its still pretty large. Thats a 6" diameter tube 28"
long. If its under your cowl (assuming it fits there), its a pretty large
radiator putting out a lot of heat. Where else do you put it? Under the
fuse its a large, draggy eyesore. It seems that to accomodate such a
muffler the best choice would be to design space within the fuse to
accomodate it. But if trying to install such a beast into an existing
design (like my RV4) you've got a real challenge.
My priorities in an exhaust system were (in order):
1) Get the heat out from under the cowl as soon as possible and minimize
the amount of exhaust pipe that can radiate heat to other under cowl
components (primarily my left side Barry mount).
2) Keep the weight down. By exiting out the side you minimize the size of
the system and at the same time minimize the requirement for undercowl
heatshields. My system could be much lighter than it is ( I tend to
overbuild). Right now its just under 10 pounds from flange to end of the
mufflers.
3) Cut the noise. I expect my system to be very loud (relative to you guys
using a tangential muffler like Tracy's or Chuck Dunlap's. But I expect my
system will take at least some of the "bark" out of the exhaust note. And I
hope to make up the balance with good ANR headsets.
Maybe the priorities will change when I hear just how loud this thing
turns out to be. I have heard Alan Tolle's unmuffled Powersport RV3 and my
impression was that it wasnt as loud as many other gen av airplanes
including T6, T34A/B, and even some Bonanzas.
Mike Wills
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