Bill, 

Here is a picture of the inner pipe of my tangential muffler.  Material is 625 Inconel.  If I were to do it over I think I would angle the slots at about 45* so they would scoop the exhaust gases as it swirls around inside the larger tube.  

Mark

On Sun, Apr 11, 2010 at 3:39 PM, Bill Schertz <wschertz@comcast.net> wrote:

Could you post a picture of the internal pipe, in fact of all the parts?

Bill Schertz
KIS Cruiser #4045
N343BS
Phase I testing

From: Mark Steitle

Sent: Friday, April 09, 2010 7:26 PM

To: Rotary motors in aircraft

Subject: [FlyRotary] Re: Tangential muffler

Al, 

Per Lynn H., the p-port is very sensitive to exhaust back pressure.  So, I made sure to put lots of V-shaped slots in the inner pipe, 109 to be exact.  My goal with my tangential muffler design was to dissipate the exhaust heat energy, chop up the exhaust pulses into small pieces while minimizing back pressure.  The jury is still out as to how successful I was at meeting these three goals, but my initial impressions are favorable.

Mark

  

On Fri, Apr 9, 2010 at 12:29 PM, Al Gietzen <ALVentures@cox.net> wrote:

I’d expect it to be very effective.

Is the total area of the slots = or > than the x-section of the 2 ½” pipe?

Is the P-port less sensitive to exhaust back pressure?

 

Al

 

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Mark Steitle
Sent: Friday, April 09, 2010 7:47 AM
To: Rotary motors in aircraft

Subject: [FlyRotary] Re: Tangential muffler

 

Al, 

 

The slotted tube exits through the aft end of the muffler.  It is 2-1/2" the whole way.  I slotted it after I was unable to drill holes through the SS.  Cutting 1" slits was very easy.  After making the cuts, I took a hammer and chisel and made a "V" shaped indent on one side of the cut to increase the exit area provided by each cut and to encourage the exhaust gasses to flow toward the exit.  Seems to be working.  I'll take some sound measurements a little later on.

 

Mark

On Fri, Apr 9, 2010 at 11:13 AM, Al Gietzen <ALVentures@cox.net> wrote:

I should make it clear that my tangential muffler uses a slotted tube that runs down through the length of the 5" tube.  This tube is also inconel and is welded to both ends, thereby adding strength to the flat ends.  I utilized Lynn's coupling design to allow for movement between the muffler and the engine.  

 

Mark;

This is interesting.  Would you care to give a bit more info – or perhaps provide a sketch? Where is the exit from the muffler? Does the exhaust exit through the slotted tube? How big is the tube?

 

Al