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Date: Tue, 8 Mar 2005 19:08:36 -0800 (PST)
From: Tom <tomtugan@yahoo.com>
Subject: Re: [FlyRotary] Re: Anechoic Muffler
To: Rotary motors in aircraft <flyrotary@lancaironline.net>
In-Reply-To: 6667
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Ed Anderson <eanderson@carolina.rr.com> wrote: 
  Ok, I've shown you mine now its your turn to show me yours {:>)
Ed A

I remember an older brother saying that to a neighbor girl.    
 
 
Ok, here it is revealed to the world.    Ed, you introduced me to the DIE concept of the intake system, where essentially pulses are reflected back toward the intake port.    I later read more about this when looking up plenums and they recommended having a flat wall for these pulses to be reflected.    My latest iteration for an 'anechoic muffler' is the opposite.  The exhaust header/muffler is shaped like a V laying on it's side, as viewed from the end of the motor.    The exhaust from the ports is shot into it between these walls and hopefully attenuated as it narrows.    At both ends of this thing you have end plates.   At one or both ends of this thing you have an exhaust port for the gasses to flow out.      The specific angle of the v probably depends on wave characteristics and needs to be putzed with to optimize.    It's maybe best constructed from thicker material to better deal with the pulses.  
 
Due to interference from the motor mount you'de probably need runners and place this outside the mount.  In this case, you don't necessarily need to orient the V on its side, you can make your feeding exhaust pipes turn 90 degrees downward into a properly oriented V and catch all the apex seal debris for inspection.   Hey, make it protrude downward from the bottom-center of your cowl and let the outside airstream cool it. 
 
Other variations,  have smaller individual v-chambers per exhaust port.   With this you have more flexibility on their placement.   Then you may or may not wish to join the exhaust gas outputs into a common exhaust pipe.  
 
Thats the basic concept.      Can you weld one of these over the weekend and give it a spin?
 
Tom Tugan


 
		
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<DIV><STRONG><EM>Ed Anderson &lt;eanderson@carolina.rr.com&gt;</EM></STRONG> wrote:
<DIV>&nbsp;</DIV>
<DIV><FONT face=Arial size=2>&nbsp; Ok, I've shown you mine now its your turn to show me yours {:&gt;)</FONT></DIV>
<BLOCKQUOTE class=replbq style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px solid">
<DIV><FONT face=Arial size=2>Ed A</FONT></DIV></BLOCKQUOTE></DIV>
<DIV>I remember an older brother saying that to a neighbor girl.&nbsp;&nbsp;&nbsp; </DIV>
<DIV>&nbsp;</DIV>
<DIV>&nbsp;</DIV>
<DIV>Ok, here it is revealed to the world.&nbsp;&nbsp;&nbsp; Ed, you introduced me to the DIE concept of the intake system, where essentially pulses are reflected back toward the intake port.&nbsp;&nbsp;&nbsp; I later read more about this when looking up plenums and they recommended having a flat wall for these pulses&nbsp;to be reflected.&nbsp;&nbsp;&nbsp; My latest iteration for an 'anechoic muffler' is the opposite.&nbsp; The exhaust header/muffler is shaped like a V laying on it's side, as viewed from the end of the motor.&nbsp;&nbsp;&nbsp; The exhaust from the ports is shot into it between these walls and&nbsp;hopefully attenuated as it narrows.&nbsp;&nbsp;&nbsp; At both ends of this thing you have end plates.&nbsp;&nbsp; At one or both ends of this thing you have an exhaust port for the gasses to flow out.&nbsp;&nbsp;&nbsp;&nbsp;&nbsp; The specific angle of the v probably depends on wave characteristics and needs to be putzed with to optimize.&nbsp;&nbsp;&nbsp; It's maybe best
 constructed from thicker material to better deal with the pulses.&nbsp; </DIV>
<DIV>&nbsp;</DIV>
<DIV>Due to interference from the motor mount you'de probably need runners and place this outside the mount.&nbsp; In this case, you don't necessarily need to orient the V on its side, you can make your feeding exhaust pipes turn 90 degrees downward into a properly oriented V and catch all the apex seal debris for inspection.&nbsp;&nbsp; Hey, make it protrude downward from the bottom-center of your cowl and let the outside airstream cool it. </DIV>
<DIV>&nbsp;</DIV>
<DIV>Other variations,&nbsp; have smaller individual v-chambers per exhaust port.&nbsp;&nbsp; With this you have more flexibility on their placement.&nbsp;&nbsp; Then you may or may not wish to&nbsp;join the exhaust gas outputs into a common exhaust pipe. &nbsp;</DIV>
<DIV>&nbsp;</DIV>
<DIV>Thats the basic concept. &nbsp;&nbsp;&nbsp;&nbsp; Can you weld one of these over the weekend and give it a spin?</DIV>
<DIV>&nbsp;</DIV>
<DIV>Tom Tugan<BR><BR></DIV>
<BLOCKQUOTE style="PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">&nbsp;</BLOCKQUOTE><p>
		<hr size=1>Celebrate Yahoo!'s 10th Birthday! <br> 
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