X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from lincoln.lisco.com ([69.18.32.37] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTP id 5437698 for flyrotary@lancaironline.net; Sun, 11 Mar 2012 22:55:10 -0400 Received-SPF: none receiver=logan.com; client-ip=69.18.32.37; envelope-from=rob@mum.edu Received: from robertsdellxp (76-76-232-229.lisco.net [76.76.232.229]) by lincoln.lisco.com (Postfix) with SMTP id 6127E2BEEE for ; Sun, 11 Mar 2012 21:54:33 -0500 (CDT) Message-ID: <8733BF92E7834120ACC2FEFD172B6061@robertsdellxp> From: "Rob" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Failure of an LS-1 D-580 type ignition coil Date: Sun, 11 Mar 2012 21:51:40 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0016_01CCFFD1.23F92500" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5931 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.6157 This is a multi-part message in MIME format. ------=_NextPart_000_0016_01CCFFD1.23F92500 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Is this the same thing that happens when manifold pressure is reduced = but RPM is increased, like when I reduce throttle to go to a lower = altitude or for landing? When I do this my EGT starts to climb to 1600 = or even 1700 degrees. This in on my Ford V6 with Tracy's EC2 and EM2. = It dosen't make cents in this case either so it must be the same = phenomenon. Do I need to worry about this climbing EGT or not? Thanks for any insights? Robert Bollinger ----- Original Message -----=20 From: Tracy=20 To: Rotary motors in aircraft=20 Sent: Saturday, March 10, 2012 8:22 AM Subject: [FlyRotary] Re: Failure of an LS-1 D-580 type ignition coil The other guys pretty much nailed it. Less burning in the chamber = and more burning in the exhaust header. Tracy Sent from my iPad On Mar 9, 2012, at 11:53 PM, Dave wrote: On 3/9/2012 10:22 PM, DLOMHEIM@aol.com wrote:=20 Tracy wrote: >As usual, the in-flight symptom was a rise in EGT = on the affected rotor. Can someone describe the science behind a "rise in EGT" when we = lose a single coil. I would have expected a drop in EGT due to less = thorough burning of the mixture and therefore excess un-burnt fuel which = I thought would provide cooler temps of the exhaust stream as it passes = the EGT probe. Must be missing something very basic here... Thanks for any clarity! :) Doug Lomheim RV-9A / 13B FWF The rotor combustion space is long and narrow at TDC. If you ignite = the fuel air charge in a rotary at tdc from only one end, the flame = front progresses slowly from one end of the "combustion chamber" to the = other. Two plugs (and coils) for each rotor are present in order to = facilitate complete burning of the fuel-air charge from opposite ends, = and to extract as much power from the charge as possible before the = "power stroke" portion of rotor rotation uncovers an exhaust port and = begins the "exhaust stroke" So.. in an abnormal condition characterized by a single coil failure = (out of 4 coils).. the affected plug is dead... and the affected rotor = has incomplete and SLOWER burning of the charge than normal. This = delayed burning persists after the exhaust port is uncovered. So instead = of exhaust gases (which have already lost heat to the block) passing by = the EGT probe, you have actual flame front (from the still burning fuel = air charge) passing the probe and combustion continues in the tailpipe. = That explains why EGT on the affected rotor would rise in a rotary with = dual plugs/coils per rotor. A single dead plug from fouling or other = causes could also provide the same result.=20 Make Sense? Dave (a lingering former rotorhead) ------=_NextPart_000_0016_01CCFFD1.23F92500 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Is this the same thing that happens = when manifold=20 pressure is reduced but RPM is increased, like when I reduce throttle to = go to a=20 lower altitude or for landing? When I do this my EGT starts to climb to = 1600 or=20 even 1700 degrees. This in on my Ford V6 with Tracy's EC2 and = EM2.  =20 It dosen't make cents in this case either so it must be the same = phenomenon. Do=20 I need to worry about this climbing EGT or not?
Thanks for any insights?
 
Robert Bollinger
----- Original Message -----
From:=20 Tracy
Sent: Saturday, March 10, 2012 = 8:22=20 AM
Subject: [FlyRotary] Re: = Failure of an=20 LS-1 D-580 type ignition coil

The other guys pretty much nailed it.   Less burning in the = chamber=20 and more burning in the exhaust header.

Tracy

Sent from my iPad

On Mar 9, 2012, at 11:53 PM, Dave <david.staten@gmail.com>=20 wrote:

On 3/9/2012 10:22 PM, DLOMHEIM@aol.com wrote:=20
Tracy wrote:  >As usual, the in-flight symptom was a = rise in=20 EGT on the affected rotor.
 
Can someone describe the science behind a "rise in EGT" when = we lose=20 a single coil.  I would have expected a drop in EGT due to = less=20 thorough burning of the mixture and therefore excess un-burnt = fuel=20 which I thought would provide cooler temps of the exhaust = stream=20 as it passes the EGT probe.
 
Must be missing something very basic here...
 
Thanks for any clarity!  :)
 
Doug Lomheim
RV-9A / 13B FWF

The rotor = combustion space=20 is long and narrow at TDC. If you ignite the fuel air charge in a = rotary at=20 tdc from only one end, the flame front progresses slowly from one = end of the=20 "combustion chamber" to the other. Two plugs (and coils) for each = rotor are=20 present in order to facilitate complete burning of the fuel-air = charge from=20 opposite ends, and to extract as much power from the charge as = possible=20 before the "power stroke" portion of rotor rotation uncovers an = exhaust port=20 and begins the "exhaust stroke"

So.. in an abnormal condition = characterized by a single coil failure (out of 4 coils).. the = affected plug=20 is dead... and the affected rotor has incomplete and SLOWER burning = of the=20 charge than normal. This delayed burning persists after the exhaust = port is=20 uncovered. So instead of exhaust gases (which have already lost heat = to the=20 block) passing by the EGT probe, you have actual flame front (from = the still=20 burning fuel air charge) passing the probe and combustion continues = in the=20 tailpipe. That explains why EGT on the affected rotor would rise in = a rotary=20 with dual plugs/coils per rotor. A single dead plug from fouling or = other=20 causes could also provide the same result.

Make = Sense?
Dave (a=20 lingering former = rotorhead)
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