I tried the Edelbrock RPM series on my plane.  It lasted about 20 hours
before self destructing.  Packing (ceramic) blew out in about 5 hours. I
sent pictures of it to the list some time ago.
Tracy Crook

How about Inconel-718 turnings off a lathe? They are a bit stiff and can cut skin
to the bone instantly but if packed into a casing should work.

Blake

Blake,
I assume that you mean that the Inconel-718 would be used for muffler packing.  What about the rest of the muffler.  Tracy stated that the RPM series muffler self destructing in 20 hours.

Wouldn't it be best to just make the entire muffler from Inconel?  I know that this stuff is ridiculously expensive but I don't want my muffler self-destructing into my pusher prop.   Every time I consider using 316-SS instead of Inconel, I remember all the stories about Tracy's mufflers being destroyed after relatively low hours.  My problem so far has been finding a supplier for Inconel tubing and sheet that is willing to sell in the small quantities we need for building our mufflers.  I've been looking for nine months without any real success.  Most suppliers that are willing to sell to individuals want to sell full sheets and uncut lengths.  The last I figured, I would have to buy about $2000 worth of Inconel and would only use about one forth of it for my system.  Is there anyone else out there who wants to build their exhaust system from 600-Inconel ???  If so, this is a product that would definitely be best to buy in a quantity group purchase.  If anyone knows of a good supplier and / or would be interested in participating in a group purchase........let me know!!!
Thanks,
Don Mitchell
Plano, Texas
Standard Fixed Gear Velocity (~70%)
Mazda 20B with T. Crook EFI / EI / Redrive
N 6 V V (Reserved)

One other thing. Don't put anything inside the muffler that could come out
in a big  chunk as I am not sure even .065 thick SS baffles would live.
I stood behind Tom Jordans supercharged 13B LongEZ when he was running it
up at max static RPM at 5 psi boost looking into the muffler through the tail
pipe and the perforated pipe inside the muffler was white hot... almost transparent.
The internal baffles get no cooling at all. Just a matter of time
before they come out IMHO.I would not use Inconel turnings in a pusher 
muffler as that implies some some sort of internal baffle to keep them
in place. Let somebody else try that with a tractor airplane. 

Use a .050 SS wall tangential muffler and you will not have to use
baffles that could melt and be ejected.

BTW aircraft muffler problems are not unique to rotary engines.
My C182 spit the guts of the muffler out on the ramp one time
when I was running it up. My passengers were standing along
side and got freqed out when they saw that chunk of metal
hit the pavement. God knows how many are scattered around
the country side.

Paul Lamar
 
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