X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao107.cox.net ([68.230.241.39] verified) by logan.com (CommuniGate Pro SMTP 5.1.10) with ESMTP id 2198424 for flyrotary@lancaironline.net; Wed, 25 Jul 2007 11:03:04 -0400 Received-SPF: none receiver=logan.com; client-ip=68.230.241.39; envelope-from=dale.r@cox.net Received: from fed1rmimpo01.cox.net ([70.169.32.71]) by fed1rmmtao107.cox.net (InterMail vM.7.08.02.01 201-2186-121-102-20070209) with ESMTP id <20070725150226.PNZO1358.fed1rmmtao107.cox.net@fed1rmimpo01.cox.net> for ; Wed, 25 Jul 2007 11:02:26 -0400 Received: from [192.168.1.101] ([72.223.48.245]) by fed1rmimpo01.cox.net with bizsmtp id Tr2R1X00P5HQYSo0000000; Wed, 25 Jul 2007 11:02:25 -0400 Message-ID: <46A76600.2050708@cox.net> Date: Wed, 25 Jul 2007 08:02:24 -0700 From: Dale Rogers Reply-To: dale.r@cox.net User-Agent: Thunderbird 2.0.0.5 (Windows/20070716) MIME-Version: 1.0 To: Rotary motors in aircraft Subject: Re: [FlyRotary] Re: bench flowtest References: In-Reply-To: Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit WRJJRS@aol.com wrote:

Kevin,

With rotaries they have found that a constantly expanding exhaust helps keep the pulse moving. It also keeps the LOUD moving. The Rotary will tolerate some back pressure, but since there is no exhaust valve it helps to be sure that there are as few reflecting surfaces as possible until the port is closing.

Bill Jepson

Okay, This brings to mind a question: how fast are those pulse moving?
It's pretty easy to figure out how long between pulses for any given
RPM, but it would be nice to know how far down the pipe a puff of
exhaust gets before the next one starts chasing it. Anyone here already
know this? (Yes, I know I can search for it on the net - well, this is my
first attempt.)

Best Regards,
Dale R.
COZY MkIV #1254