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From: "Ed Anderson" <eanderson@carolina.rr.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
References: <list-552988@logan.com>
Subject: Re: [FlyRotary] Re: New Muffler Design
Date: Wed, 1 Dec 2004 17:07:12 -0500
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No, Joe, I did not consider that orientation of the disc.  My objective
(partially in order to keep the design simply) was to modify a solid disc
(well it actually has a 1/2" hole in the center simply because I couldn't
find a solid disc of the necessary thickness of SS) to:
1.  Reflect the FAW pulse
2. Permit unhindered (relatively speaking) flow of gas past the disc

My objective was to reflect one wave back on the next incoming wave in hope
of attenuating both (If I understand the theory and characteristics of the
FAW pulses).  Certainly anything you can do to keep the sound energy from
coming out the end of the tube will help reduce the noise level.  However,
you obviously do not want to interfere (any more than you can help) with the
exiting of the gas. Again to keep construction fairly simply I just stuck
the 2" dia discs in a 2 1/8" tube after modifying them.

But, you are thinking in the right direction with baffles alternating on
each side, the FAW would see essentially a solid wall looking down the tube
(assuming your baffles slightly overlap in the center)  but the gas
molecules of course would flow around the baffles.

Ed

----- Original Message -----
From: "Joe Hull" <JoeH@PilgrimTech.com>
To: "Rotary motors in aircraft" <flyrotary@lancaironline.net>
Sent: Wednesday, December 01, 2004 4:35 PM
Subject: [FlyRotary] Re: New Muffler Design


> Ed -
> Did you consider putting the discs in at an angle instead of
> perpendicular to the longitudinal direction? I've wondered whether
> having baffles at angles wouldn't increase the chaos of waves - i.e.
> increase attenuation/cancellation. Maybe even a tube where baffles are
> inserted from alternate sides. E.g.
>
> -----------------------------
>    /                     /
>   /                     /
>             /
>            /
> -----------------------------
>
> Joe Hull
> Bellevue (Seattle), Washington
> Cozy MkIV #991 (working on Engine & Electrical & Finishing)
> http://www.maddyhome.com/canardpages/pages/JoeHull/index.html
>
>
>
> >>  Homepage:  http://www.flyrotary.com/
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>