X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from wa-out-1112.google.com ([209.85.146.181] verified) by logan.com (CommuniGate Pro SMTP 5.2.11) with ESMTP id 3413092 for flyrotary@lancaironline.net; Tue, 06 Jan 2009 11:52:38 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.146.181; envelope-from=rwstracy@gmail.com Received: by wa-out-1112.google.com with SMTP id j4so4218551wah.3 for ; Tue, 06 Jan 2009 08:52:00 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:message-id:date:from:sender :to:subject:in-reply-to:mime-version:content-type:references :x-google-sender-auth; bh=sDG8eYnLwsEhvOI/yprd9NjKRjBwnYDR8KalvdUIX2Y=; b=rqhAJrg5PWwWRHDuYGluUby4gz6Ko8CrRRwgD/t9JyOWoWpY8ebEbhhNxlofMOBmN7 QfpnPDOJmEip7ZWtLRk2iEpqZJDRMa/AVrpljbgzhBYcAo4NSzMXnjb0F3ia7HbaucM9 PbBLy2pR7b/xaK1u5aNcvwZpgVekth96t7dBc= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:in-reply-to:mime-version :content-type:references:x-google-sender-auth; b=gUoznfojWFLifCovFsaAYZi+b+erZo61IF/DruCcGY/YSvU5tScz//xOfDpHbVI4cp dOZ99KKNWwjFSxy7ZkAdE+XD2d01PwHiccHVPGteg9cV2AOstrv0dAfcyJv6lNSE9ZqQ eCtGP/pgDMMY4KGe5YFZWIpoawz1Pz1DtR/Vc= Received: by 10.114.125.15 with SMTP id x15mr14641192wac.42.1231260720805; Tue, 06 Jan 2009 08:52:00 -0800 (PST) Received: by 10.114.61.10 with HTTP; Tue, 6 Jan 2009 08:52:00 -0800 (PST) Message-ID: <1b4b137c0901060852u262f5ean45efe0c2edaa7b41@mail.gmail.com> Date: Tue, 6 Jan 2009 11:52:00 -0500 From: "Tracy Crook" Sender: rwstracy@gmail.com To: "Rotary motors in aircraft" Subject: Re: [FlyRotary] Re: Muffler design (was 20B isssues . . ) In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_Part_192803_4916039.1231260720800" References: X-Google-Sender-Auth: b5ab47c72783a5c2 ------=_Part_192803_4916039.1231260720800 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Interesting stuff Ernest, Hope this turns up some good results. I haven't had time to really go into muffler theory so I've just observed what the car & motorcycle makers do. Based on these observations only, I've concluded that unless we come up with a new concept, there is no substitute for size and cubic inches. There is also a very important issue of muffler volume to outlet area ratio. My 70 HP ATV has an unbelievably small outlet and works very well. I'm going to try different size outlets on the -4 installation and see what I can learn. Tracy On Tue, Jan 6, 2009 at 10:12 AM, Ernest Christley wrote: > Al Gietzen wrote: > >> Unless I did the math wrong; the maximum filling fraction you can get >> with these rods is about .8. So I think there would be a problem there. >> >> >> > Well, I've worked out a way to put together a simple experimental bench-top > apparatus that will allow me to quickly put together various crystal > arrangements. I've got some recordings of rotaries running. I'll set up a > configuration, pipe the recording into one end, record it on the other, and > then do a spectral analysis on the new recording. Running the analysis on a > recording without the intervening filter will be my control. > > Now that I'm excited. I've got to try to get some work done. 8*) > > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > ------=_Part_192803_4916039.1231260720800 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline Interesting stuff Ernest,  Hope this turns up some good results.

I haven't had time to really go into muffler theory so I've just observed what the car & motorcycle makers do.  Based on these observations only,  I've concluded that unless we come up with a new concept, there is no substitute for size and cubic inches.  There is also a very important issue of muffler volume to outlet area ratio.   My 70 HP ATV has an unbelievably small outlet and works very well.  I'm going to try different size outlets on the -4 installation and see what I can learn.

Tracy
  

On Tue, Jan 6, 2009 at 10:12 AM, Ernest Christley <echristley@nc.rr.com> wrote:
Al Gietzen wrote:
Unless I did the math wrong; the maximum filling fraction you can get
 with these rods is about .8.  So I think there would be a problem there.

 
Well, I've worked out a way to put together a simple experimental bench-top apparatus that will allow me to quickly put together various crystal arrangements.  I've got some recordings of rotaries running.  I'll set up a configuration, pipe the recording into one end, record it on the other, and then do a spectral analysis on the new recording.  Running the analysis on a recording without the intervening filter will be my control.

Now that I'm excited.  I've got to try to get some work done. 8*)

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