X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imo-m21.mx.aol.com ([64.12.137.2] verified) by logan.com (CommuniGate Pro SMTP 4.3.5) with ESMTP id 1027131 for flyrotary@lancaironline.net; Thu, 30 Jun 2005 11:12:20 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.137.2; envelope-from=WRJJRS@aol.com Received: from WRJJRS@aol.com by imo-m21.mx.aol.com (mail_out_v38_r1.7.) id q.1b8.162edce0 (25711) for ; Thu, 30 Jun 2005 11:11:32 -0400 (EDT) From: WRJJRS@aol.com Message-ID: <1b8.162edce0.2ff565a3@aol.com> Date: Thu, 30 Jun 2005 11:11:31 EDT Subject: Re: [FlyRotary] Re: P Ports working on dyno To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="-----------------------------1120144291" X-Mailer: 9.0 SE for Windows sub 5012 -------------------------------1120144291 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 6/30/2005 4:53:28 AM Pacific Standard Time, jerryhey@earthlink.net writes: Bill, the muffler did have the long tailpipe. I am disappointed by the test. Was it too loud or not? In testing Chuck Dunlop's plane outdoors, Paul stood about 20 feet away with the sound meter. Also, why not make a power run when we had the chance? I was looking for info that would with the design.........Jerry Jerry, 123 db is loud. If that is at 2 feet then it may be tolerable. One thing I was going to mention was that we should be trying to make the muffler at least optically dense. By that I mean that the exit hole needs to be unable to "see" the inlet pipes. One of the basic tennets has always been to make the shock wave reflect at least once on the way to the exit. The swirl effect of the tangential muffler does help, but if the cannister is full of exhaust gas the bark of the rotaries initial shock wave is an even wavefront dipersing from the tubes entry into the can. If the shock wave runs directly across the canister there will be a loud exit bark. The design could probably be made slightly quieter by enlarging the diameter of the cool tube to pervent a straighline path from the inlet tube to the exit. Bill Jepson -------------------------------1120144291 Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable
In a message dated 6/30/2005 4:53:28 AM Pacific Standard Time,=20 jerryhey@earthlink.net writes:
<= FONT=20 style=3D"BACKGROUND-COLOR: transparent" face=3DArial color=3D#000000 size= =3D2>Bill,=20 the muffler did have the long tailpipe.  I am disappointed by the=20
test.   Was it too loud or not?  In testing Chuck Dunlo= p's=20 plane
outdoors, Paul stood about 20 feet away with the sound meter.&nb= sp;=20 Also,
why not make a power run when we had the chance?   I w= as=20 looking for
info that would with the=20 design.........Jerry
Jerry,
 123 db is loud. If that  is at 2 feet then it may be tolerab= le.=20 One thing I was going to mention was that we should be trying to make the=20 muffler at least optically dense. By that I mean that the exit hole needs to= be=20 unable to "see" the inlet pipes. One of the basic tennets has always been to= =20 make the shock wave reflect at least once on the way to the exit. The s= wirl=20 effect of the tangential muffler does help, but if the cannister is full of=20 exhaust gas the bark of the rotaries initial shock wave is an even wavefront= =20 dipersing from the tubes entry into the can. If the shock wave runs directly= =20 across the canister there will be a loud exit bark. The design could probabl= y be=20 made slightly quieter by enlarging the diameter of the cool tube to pervent=20= a=20 straighline path from the inlet tube to the exit.
 
Bill Jepson
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