I use the stock manifold on the test stand with heavy wall mild steel pipe and it has held up well. I could never bear the thought of bolting that 18 pound chunk of iron to an airplane though. I flew the HushPowerII muffler for the first flight test yesterday. I easily got back my 4 mph lost to drag of the Spintech (Sun 100 here I come!) and the noise level is about the same, perhaps slightly louder, I forgot to take the sound meter along. Tracy ----- Original Message ----- From: sqpilot@earthlink Sent: Saturday, February 21, 2004 8:45 AM To: Rotary motors in aircraft Subject: [FlyRotary] exhaust My 13b engine is ready to run....I ordered a VAM muffler, but since it has
not yet happened, I was wondering if I could get away with using the stock
cast iron manifold with a straight pipe attached to it, which would exit
through the bottom of the cowling. I should mention that this is on a
pusher. George Graham told me that he was using a straight, (or slightly
bent) pipe, and possibly Perry Mick is or was using the stock cast iron
manifold? My thinking is that although it is heavy, it might possibly
absorb a lot of the initial heat as it is exiting the exhaust ports, acting
like a heat collector, and I might not need expensive inconel or 321
stainless after the exhaust goes through the stock manifold first? Would
the cast iron manifold absorb much of the heat and possibly muffle some of
the noise as it is bounced around inside of the stock manifold? I'm
probably grasping at straws, but with all the knowledge and experience in
this group, I figure it wouldn't hurt to ask. Thanks to all for your
opinions and advice. Paul Conner, 13b powered SQ2000
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