X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from imr-ma03.mx.aol.com ([64.12.206.41] verified) by logan.com (CommuniGate Pro SMTP 5.4c2) with ESMTP id 4913787 for flyrotary@lancaironline.net; Mon, 21 Mar 2011 12:49:24 -0400 Received-SPF: pass receiver=logan.com; client-ip=64.12.206.41; envelope-from=Lehanover@aol.com Received: from imo-da02.mx.aol.com (imo-da02.mx.aol.com [205.188.169.200]) by imr-ma03.mx.aol.com (8.14.1/8.14.1) with ESMTP id p2LGmZsq006209 for ; Mon, 21 Mar 2011 12:48:35 -0400 Received: from Lehanover@aol.com by imo-da02.mx.aol.com (mail_out_v42.9.) id q.10a3.88cff4 (55832) for ; Mon, 21 Mar 2011 12:48:34 -0400 (EDT) Received: from magic-d18.mail.aol.com (magic-d18.mail.aol.com [172.19.155.134]) by cia-md06.mx.aol.com (v129.9) with ESMTP id MAILCIAMD061-da184d8781611da; Mon, 21 Mar 2011 12:48:34 -0400 From: Lehanover@aol.com Message-ID: <30e49.14a38a4f.3ab8db61@aol.com> Date: Mon, 21 Mar 2011 12:48:33 EDT Subject: Re: [FlyRotary] Re: Forced Landing. To: flyrotary@lancaironline.net MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="part1_30e49.14a38a4f.3ab8db61_boundary" X-Mailer: 9.0 Security Edition for Windows sub 5382 X-AOL-IP: 72.187.199.116 X-Spam-Flag:NO X-AOL-SENDER: Lehanover@aol.com --part1_30e49.14a38a4f.3ab8db61_boundary Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit In a message dated 3/20/2011 9:38:38 P.M. Eastern Daylight Time, msteitle@gmail.com writes: Bill, The DNA (Dynamic Noise Attenuation) muffler is the only one I've used that has not self-destructed in a matter of hours, except for the tangential muffler which was too restrictive and caused other problems and gave poor performance. (I should have listened to Lynn.) The DNA is not as quiet as other mufflers, but it has worked for about 100 hours so far with no sign of fatigue. Also, it has no packing to blow/burn out. ANR headsets are a given. Mark The first outing of one of my Rotaries involved a tow to south Florida with a tube frame first gen body. At Sebring the driver came in saying it won't pull over 7,000 RPM. It would free rev to 9,000 RPM but not with a load on it. We checked compression and it was fine (Usually means all is well) plus hot start was instantly so again all is well. It turned out that we were right on best power tune ( nearly highest EGT) and melted the new Flowmaster muffler designed for the 427 Ford engine. All of the partitions were piled up at the exit blocking the outlet nearly 100%. The engine sounded great and ran fine, but had no power. This all happened in one lap. So the exit went from partially blocked and still running OK, to blocked just a bit more, and running so poorly that even the driver noticed it. So, I deduce that the range of blockage percentagees is very small from unnoticed to not flying is, or can be very small. Since the loss of power is from exhaust gas dilution of the incoming charge, and at higher back pressure settings from displaced intake charge, from excessive exhaust gasses still present when the intake port opens, that the engine begins to loose effective displacement. So the power loss may not involve a sudden change in output until the blockage has been present for some time. Then the one piece that changes the blockage by a few percent, is the last thing you notice first. It is possible that reducing throttle slightly may get back some lost power, as the intake length tune changes slightly and reduced flow lowers back pressure. But that is a guess. Lynn E. Hanover --part1_30e49.14a38a4f.3ab8db61_boundary Content-Type: text/html; charset="US-ASCII" Content-Transfer-Encoding: quoted-printable

In a message dated 3/20/2011 9:38:38 P.M. Eastern Daylight Time,=20 msteitle@gmail.com writes:

Bill, =20

The DNA (Dynamic Noise Attenuation) muffler is the only one I've us= ed=20 that has not self-destructed in a matter of hours, except for the tangen= tial=20 muffler which was too restrictive and caused other problems and gave poo= r=20 performance. (I should have listened to Lynn.) The DNA is no= t as=20 quiet as other mufflers, but it has worked for about 100 hours so far wi= th no=20 sign of fatigue. Also, it has no packing to blow/burn out. A= NR=20 headsets are a given.

Mark

The first outing of one of my Rotaries involved a tow to south Florid= a with=20 a tube frame first gen body. At Sebring the driver came in saying it won't= pull=20 over 7,000 RPM. It would free rev to 9,000 RPM but not with a load on it.= We=20 checked compression and it was fine (Usually means all is well) plus hot= start=20 was instantly so again all is well. It turned out that we were right on be= st=20 power tune ( nearly highest EGT) and melted the new Flowmaster muffler des= igned=20 for the 427 Ford engine. All of the partitions were piled up at the exit= =20 blocking the outlet nearly 100%. The engine sounded great and ran fine, bu= t had=20 no power. This all happened in one lap. So the exit went from partially bl= ocked=20 and still running OK, to blocked just a bit more, and running so poorly th= at=20 even the driver noticed it. So, I deduce that the range of blockage percen= tagees=20 is very small from unnoticed to not flying is, or can be very small.

Since the loss of power is from exhaust gas dilution of the incoming= =20 charge, and at higher back pressure settings from displaced intake charge,= from=20 excessive exhaust gasses still present when the intake port opens, that th= e=20 engine begins to loose effective displacement.

So the power loss may not involve a sudden change in output until the= =20 blockage has been present for some time. Then the one piece that changes= the=20 blockage by a few percent, is the last thing you notice first.

It is possible that reducing throttle slightly may get back some lost= =20 power, as the intake length tune changes slightly and reduced flow lowers= back=20 pressure. But that is a guess.

Lynn E. Hanover

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