If your W&B can handle the weight you can definitely use it as exhaust manifold. But unless you use heavy (1/8") steel pipe I would still use SS for the exhaust pipe. The heat has to go somewhere. Unless you plan to only run it long enough to heat up the stock cast iron manifold (a couple of minutes). On the other hand, that manifold will probably take the edge off the exhaust pulses that are so damaging to the exhaust system.

As a temporary solution, I would say go for it - with thick pipe and proper heat shielding !!

Oh, considering it's a pusher: clamp or weld some attach points to the pipe and connect it to the engine or engine mount with good strong aircraft wire: something that will prevent it from falling into the prop in case it breaks off. I'm not kidding here: engine or airframe might just hit some resonance point that will break it off no matter how strong the weld.

Finn

sqpilot@earthlink wrote:

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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