X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [207.115.11.53] (HELO fmailhost01.isp.att.net) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2928917 for flyrotary@lancaironline.net; Mon, 19 May 2008 10:56:08 -0400 Received-SPF: none receiver=logan.com; client-ip=207.115.11.53; envelope-from=keltro@att.net Received: from fwebmail07.isp.att.net ([204.127.218.107]) by isp.att.net (frfwmhc03) with SMTP id <20080519145529H0300ll838e>; Mon, 19 May 2008 14:55:29 +0000 X-Originating-IP: [204.127.218.107] Received: from [4.245.53.70] by fwebmail07.isp.att.net; Mon, 19 May 2008 14:55:27 +0000 From: "Kelly Troyer" To: "Rotary motors in aircraft" Subject: Re: Exhaust Progress Date: Mon, 19 May 2008 14:55:27 +0000 Message-Id: <051920081455.1851.483194DE000EE91F0000073B22230706129B0A02D29B9B0EBF019D9B040A05@att.net> In-Reply-To: X-Mailer: AT&T Message Center Version 1 (Mar 10 2008) X-Authenticated-Sender: a2VsdHJvQGF0dC5uZXQ= MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="NextPart_Webmail_9m3u9jl4l_1851_1211208927_0" --NextPart_Webmail_9m3u9jl4l_1851_1211208927_0 Content-Type: text/plain Content-Transfer-Encoding: 8bit Thanks Lynn.........I finally got it through my thick head !! -- Kelly Troyer "Dyke Delta"_13B ROTARY Engine "RWS"_RD1C/EC2/EM2 "Mistral"_Backplate/Oil Manifold -------------- Original message from Lehanover@aol.com: -------------- The rule is that short collectors tune over a small range of RPM. Long collectors tune over a broad range of RPM. Note that in racing systems, you always see the tubes entering the collector with all of the tubes having been run in parallel for some distance. The collectors will be 4 to 8 tube diameters long. Cutting off the short collector and adding material to increase the overall length to come out to 6 to 8 tube diameters was what I was trying to get across. Flow is supersonic in the rotary exhaust flow and errors in construction can cause profound outcomes. So make it smooth inside. The flow slowing to subsonic inside the muffler creates the many sound control problems. I was interested in the Spintec because of the many turning vanes holding the flat sides together may have extended its life. Otherwise only round mufflers survive for very long. Round is not a good shape for aircraft use. Stainless swarf filled stainless mufflers hold up the longest. The 4" pipe in the picture was later turned down to face the track when readings exceeded 103 dB. Lynn E. Hanover In a message dated 5/19/2008 9:10:24 AM Eastern Daylight Time, keltro@att.net writes: Doug, Lynn suggested that you cut through the collector half way down and extend its length about 1/3.........What is not clear to me is if the cut and extension would be on the inlet or outlet of the collector ?? Why add an extension in the middle of the collector ?? Why not at the end of the outlet if that is where he is saying it should be added ?? Am I not seeing the big picture here ?? -- Kelly Troyer --NextPart_Webmail_9m3u9jl4l_1851_1211208927_0 Content-Type: multipart/related; boundary="NextPart_Webmail_9m3u9jl4l_1851_1211208927_1" --NextPart_Webmail_9m3u9jl4l_1851_1211208927_1 Content-Type: text/html Content-Transfer-Encoding: 8bit

Thanks Lynn.........I finally got it through my thick head !!

--
Kelly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistral"_Backplate/Oil Manifold

-------------- Original message from Lehanover@aol.com: --------------

The rule is that short collectors tune over a small range of RPM. Long collectors tune over a broad range of RPM. Note that in racing systems, you always see the tubes entering the collector with all of the tubes having been run in parallel for some distance. The collectors will be 4 to 8 tube diameters long.

Cutting off the short collector and adding material to increase the overall length to come out to 6 to 8 tube diameters was what I was trying to get across. Flow is supersonic in the rotary exhaust flow and errors in construction can cause profound outcomes. So make it smooth inside. The flow slowing to subsonic inside the muffler creates the many sound control problems. I was interested in the Spintec because of the many turning vanes holding the flat sides together may have extended its life. Otherwise only round mufflers survive for very long. Round is not a good shape for aircraft use. Stainless swarf filled stainless mufflers hold up the longest.

The 4" pipe in the picture was later turned down to face the track when readings exceeded 103 dB.

Lynn E. Hanover

In a message dated 5/19/2008 9:10:24 AM Eastern Daylight Time, keltro@att.net writes:

Doug,

Lynn suggested that you cut through the collector half way down and

extend its length about 1/3.........What is not clear to me is if the cut and

extension would be on the inlet or outlet of the collector ?? Why add an

extension in the middle of the collector ?? Why not at the end of the outlet

if that is where he is saying it should be added ?? Am I not seeing the big

picture here ??

--
Kelly Troyer

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