X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from EXHUB003-2.exch003intermedia.net ([207.5.74.29] verified) by logan.com (CommuniGate Pro SMTP 5.2.16) with ESMTPS id 3877661 for flyrotary@lancaironline.net; Wed, 07 Oct 2009 09:04:02 -0400 Received-SPF: none receiver=logan.com; client-ip=207.5.74.29; envelope-from=jwhaley@datacast.com Received: from EXVMBX003-5.exch003intermedia.net ([207.5.74.45]) by EXHUB003-2.exch003intermedia.net ([207.5.74.29]) with mapi; Wed, 7 Oct 2009 06:03:23 -0700 From: Jeff Whaley To: Rotary motors in aircraft Date: Wed, 7 Oct 2009 06:04:15 -0700 Subject: RE: [FlyRotary] Mystery Radio Noise Thread-Topic: [FlyRotary] Mystery Radio Noise Thread-Index: AcpGzxVXgei7l+8xSeSPoy5LQASQGAAfgajA Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_C03ABB0A7362B84BB53D544B3C305E0E0153652EA611EXVMBX0035e_" MIME-Version: 1.0 --_000_C03ABB0A7362B84BB53D544B3C305E0E0153652EA611EXVMBX0035e_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable It's possible that the slightly different air pressure on the belly skin, c= ausing metal flexing is affecting the antenna ground plane. You may need a= stiffener plate. Check the connection of your antenna ground to airframe ground. Jeff From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Beh= alf Of Bobby J. Hughes Sent: Tuesday, October 06, 2009 6:54 PM To: Rotary motors in aircraft Subject: [FlyRotary] Mystery Radio Noise Got the plane back together late Sunday just in time for a few laps around = the airport. Oil temps showed major improvements with the larger inlets. Cl= imbing at 100 mph to 3000 ft, 7200 rpm on take off, reduced to 6500 rpm at = 500 ft agl. Maintained 6500 rpm at 37" MP for several circuits. Oil temps went to 220F = but started to come down when I leveled off. Water stay at 190F or below. O= AT was 88F . My new "test" ducts do not seal as well as the first set so h= opefully I still have room for improvement. While level at 3000 ft \ ground speed showing 145 knots I pitched the nose = down and heard a startling noise in my headset. Almost like wires shorting.= Leveled off and noise stopped. Pitched up no change. Pitch down the noise = returned. I decided it could not be wiring and repeated this several times.= It also happened at slower speeds but I don't remember at what speed it st= opped. It doesn't happen on the ground at full power run up. My guess is my= new exhaust is somehow affecting the comm antenna when in a nose down atti= tude. The exhaust ends about 1 ft in front and 1 ft to the side of the ante= nna. Any ideas? Bobby J Hughes RV-10 SC Renesis --_000_C03ABB0A7362B84BB53D544B3C305E0E0153652EA611EXVMBX0035e_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

It’s possible that the slightly different air pressure= on the belly skin, causing metal flexing is affecting the antenna ground plane= . You may need a stiffener plate.

Check the connection of your antenna ground to airframe grou= nd.

Jeff

From: Rotary motors= in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. Hughes
Sent: Tuesday, October 06, 2009 6:54 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Mystery Radio Noise

Got the plane back together late Sunday just in time for a few laps around the airport. Oil temps showed major improvements with the larger inlets. Climbing at 100 mph to 3000 ft, 7200 rpm on take off, reduced to 6500 = rpm at 500 ft agl.

Maintained 6500 rpm at 37" MP for several circuits. Oil temps went to 220F but started to come down when I leveled off. Water stay at 190F or below. OAT w= as 88F . My new "test" ducts do not seal as well as the f= irst set so hopefully I still have room for improvement.

While level at 3000 ft \ ground speed showing 145 knots I pitched the n= ose down and heard a startling noise in my headset. Almost like wires shorting. Leveled off and noise stopped. Pitched up no change. Pitch down t= he noise returned. I decided it could not be wiring and repeated this several times. It also happened at slower speeds but I don't remember at what speed= it stopped. It doesn't happen on the ground at full power run up. My guess is = my new exhaust is somehow affecting the comm antenna when in a nose down attit= ude. The exhaust ends about 1 ft in front and 1 ft to the side of the antenna. A= ny ideas?

Bobby J Hughes

RV-10 SC Renesis

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