X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [66.219.56.245] (HELO mail.qnsi.net) by logan.com (CommuniGate Pro SMTP 5.4c2) with ESMTP id 4924196 for flyrotary@lancaironline.net; Sun, 27 Mar 2011 17:42:28 -0400 Received-SPF: none receiver=logan.com; client-ip=66.219.56.245; envelope-from=bhughes@qnsi.net Return-Receipt-To: "Bobby J. Hughes" Subject: RE: [FlyRotary] Re: Exhaust obstruction test MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01CBECD0.F24CB17A" Date: Sun, 27 Mar 2011 16:47:26 -0600 Disposition-Notification-To: "Bobby J. Hughes" Content-class: urn:content-classes:message Message-ID: <74120FDE88CAFE4DBDA8814BCE20A3F32D3859@qnsi-mail.qnsi.net> X-MS-Has-Attach: X-MimeOLE: Produced By Microsoft Exchange V6.5 X-MS-TNEF-Correlator: Thread-Topic: [FlyRotary] Re: Exhaust obstruction test Thread-Index: AcvssgT1wp4STVKtQJqXLCY82cdY3AAHfoFg References: From: "Bobby J. Hughes" To: "Rotary motors in aircraft" This is a multi-part message in MIME format. ------_=_NextPart_001_01CBECD0.F24CB17A Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable The most likely culprit remains a blocked exhaust. Thanks again for taking the time to setup and conduct the test. If you need someone to test your injector delay circuits with higher MP and an electric prop I'll volunteer. Of course if they help resolve tuning issues you may never get them back. =20 =20 Bobby =20 =20 =20 ________________________________ From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Steven W. Boese Sent: Sunday, March 27, 2011 11:59 AM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Exhaust obstruction test =20 Bobby, =20 The MAP in the plot is manifold pressure in inches of Hg. The throttle setting was not changed while the exhaust valve was closing or closed. The increase in manifold pressure results from the decreased air requirement when the rpm decreases due to the choked off exhaust. A decrease in air volume drawn out of the intake plenum along with an unchanged throttle body opening gives a manifold pressure rise. =20 This is consistent with what you experienced. =20 I've attached a couple of photos of the test setup. =20 One other observation that I forgot to mention is that with the valve even partly closed, the noise level decreased remarkably. =20 Steve =20 =20 From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. Hughes Sent: Sunday, March 27, 2011 12:33 PM To: Rotary motors in aircraft Subject: [FlyRotary] Re: Exhaust obstruction test =20 Steve, =20 Thank you for conducting this test. The attachment contains the data my Advanced Flight Systems engine monitor captured. It logs in five second intervals. A lot can happen in five seconds when the pilot is throwing switches and opening and closing the throttle. The data shows I did not re-enable the primary injector switch until after landing. So no rpm or fuel flow data was captured during most of the glide. Oil pressure indicates the prop was driving the engine. I don't remember if I bypassed part of the super charger flow or not. The manifold pressure before the event was only 36" MP so I was not a full power. The rpm dropped from 6700 to 2500. Manifold pressure started dropping but I'm sure I was pumping the throttle and may have pulled the super charger bypass. What I don't understand is the last seven lines of data. MP is between 18 and 29.4 at idle. This is while I was trying to taxi but could not move the plane.=20 =20 Your data supports a sharp drop in rpm. Is the MAP plot EC2 fuel map or manifold pressure? If manifold pressure your test also indicates a high manifold pressure with a low rpm condition. =20 Bobby =20 ------_=_NextPart_001_01CBECD0.F24CB17A Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable

The most likely culprit remains a = blocked exhaust. Thanks again for taking the time to setup and conduct the test. = If you need someone to test your injector delay circuits with higher MP and an electric prop I’ll volunteer. Of course if they help resolve = tuning issues you may never get them back.

 

 

Bobby

 

 

 

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Steven W. Boese
Sent: Sunday, March 27, = 2011 11:59 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Exhaust obstruction test

 

Bobby,

=

 

=

The MAP in the plot is manifold = pressure in inches of Hg.  The throttle setting was not changed while the = exhaust valve was closing or closed.  The increase in manifold pressure = results from the decreased air requirement when the rpm decreases due to the = choked off exhaust.  A decrease in air volume drawn out of the intake plenum  along with an unchanged throttle body opening gives a manifold = pressure rise.

 

=

This is consistent with what you experienced.

 

=

I’ve attached a couple of = photos of the test setup.

 

=

One other observation that I = forgot to mention is that with the valve even partly closed, the noise level = decreased remarkably.

 

=

Steve

 

=

 <= /p>

From: = Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Bobby J. = Hughes
Sent: Sunday, March 27, = 2011 12:33 PM
To: Rotary motors in aircraft
Subject: [FlyRotary] Re: = Exhaust obstruction test

 

Steve,

 

Thank you for conducting this test. The attachment = contains the data my Advanced Flight Systems engine monitor captured. It logs in = five second intervals. A lot can happen in five seconds when the pilot is = throwing switches and opening and closing the throttle. The data shows I did not re-enable the primary injector switch until after landing. So no rpm or = fuel flow data was captured during most of the glide. Oil pressure = indicates the prop was driving the engine. I don’t remember if I bypassed = part of the super charger flow or not.  The manifold pressure before the = event was only 36” MP so I was not a full power. The rpm dropped from 6700 = to 2500. Manifold pressure started dropping but I’m sure I was pumping the throttle and may have pulled the super charger bypass. What I = don’t understand is the last seven lines of data. MP is between 18 and 29.4 at = idle. This is while I was trying to taxi but could not move the plane. =

 

Your data supports a sharp drop in rpm.  Is the = MAP  plot EC2 fuel map or manifold pressure? If manifold pressure your = test also indicates a high manifold pressure with a low rpm = condition.

 

Bobby

 

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