I don't think those are tangential. Here is Dave Atkin's Inconel
tangential. Weighs less than four pounds as I recall and it
is indeed quieter than a 172 with a different sound of course.
The down pipe is a bit too restrictive IMHO.

Paul Lamar

Paul,

  Dave's muffler may well be Inconel and may be as light as 4 pounds. But
it appears from the photo that the exhaust flange is one of those 1/2"
thick mild steel pieces from Racing Beat. That flange alone probably weighs
8 pounds. Just dont want anyone to be disappointed if they spend huge $ for
Inconel expecting a 4 pound exhaust and wind up with one that weighs 12 pounds.

Mike Wills

You got a good point there Mike.
It is not as bad as you think. If it were 1/2 inch thick
it would be  about 4.7 pounds. 3/8 is more like it and that would
be about 3.5 pounds. The lightest thing to do is do what Everett did
and go to a four bolt exhaust flange.
Paul;

My Dave Atkins type tangential Muffler/manifold for the 3-rotor; inconel with the Racing Beat
flange weighs 12.5 lbs.

Enjoy your white Christmas.

Al

The 20b is a much longer engine with two rather wide
intermediate housings.

(4.7' flange + 4' muffler) = 8.7' X 1.5 for the 3 rotor is 13.05 pounds. 
Pretty close :)

What is the wall thickness on the inconel Al? Dave claimed
the one in the picture was .035". The Racing beat flange thickness?

Paul Lamar

 
The AirCraft Rotary Engine NewsLetter.  Powered by Linux.
ACRE NL web site. http://home.earthlink.net/~rotaryeng/            
Copyright 1998-2002 All world wide rights reserved.