X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from madison.lisco.com ([69.18.32.36] verified) by logan.com (CommuniGate Pro SMTP 5.4.4) with ESMTP id 5438560 for flyrotary@lancaironline.net; Mon, 12 Mar 2012 12:14:42 -0400 Received-SPF: none receiver=logan.com; client-ip=69.18.32.36; envelope-from=rob@mum.edu Received: from robertsdellxp (76-76-232-229.lisco.net [76.76.232.229]) by madison.lisco.com (Postfix) with SMTP id 6F09E249C4 for ; Mon, 12 Mar 2012 11:14:05 -0500 (CDT) Message-ID: <48DB8BE0030F44E982A8E8753569F9C3@robertsdellxp> From: "Rob" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Failure of an LS-1 D-580 type ignition coil Date: Mon, 12 Mar 2012 11:14:05 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0019_01CD0041.3C73AAE0" 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_0019_01CD0041.3C73AAE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks for you input Tracy. I haven't checked my mixture monitor under this condition yet. I'll = check that next time I fly but I do notice that the EM2 indicates that = the fuel flow, GPH, starts to be reduced as the MP decreases and the EGT = increases. I have been told that I should try to avoid EGT's above 1550 = degrees and definatelly not above 1600. In spite of these high temps = upon decent I look for overheated spark plugs and damage piston top and = don't see any indication of over heating. I really have to richen the = mixture a lot to keep the EGT under control so the question is am I just = adding more fuel where it is not needed when I'm reducing power.=20 I have been meaning to use the auto mixture feature in the EM2 to fix = this but I'm not sure it is necessary. Maybe I should just adjust the = mixture so it at leased stays below 1600 degrees.=20 Does this sound reasonable. Robert Bollinger EC2 EM2 works great. In Ford V6 ----- Original Message -----=20 From: Tracy=20 To: Rotary motors in aircraft=20 Sent: Monday, March 12, 2012 7:19 AM Subject: [FlyRotary] Re: Failure of an LS-1 D-580 type ignition coil This is a different thing entirely. My guess is that your mixture is = changing at lower MP and raising the EGT. Assuming the ignition timing = is OK, this is probably what you want. Higher EGT due to leaner mixture = at low power wont hurt anything within limits. I don't know the limits = of this engine of course. What does your mixture monitor tell you = under these conditions compared to high throttle? Tracy On Sun, Mar 11, 2012 at 10:51 PM, Rob wrote: 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_0019_01CD0041.3C73AAE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks for you input = Tracy.
 
I haven't checked my mixture monitor = under this=20 condition yet. I'll check that next time I fly but I do notice that the = EM2=20 indicates that the fuel flow, GPH, starts to be reduced as the MP = decreases and=20 the EGT increases. I have been told that I should try to avoid EGT's = above 1550=20 degrees and definatelly not above 1600. In spite of these high temps = upon decent=20 I look for overheated spark plugs and damage piston top and don't see = any=20 indication of over heating. I really have to richen the mixture a lot to = keep=20 the EGT under control so the question is am I just adding more fuel = where it is=20 not needed when I'm reducing power.
I have been meaning to use the auto = mixture feature=20 in the EM2 to fix this but I'm not sure it is necessary. Maybe I should = just=20 adjust the mixture so it at leased stays below 1600 degrees. =
Does this sound = reasonable.
 
Robert Bollinger
EC2 EM2 works great.
In Ford V6
 
----- Original Message -----
From:=20 Tracy
Sent: Monday, March 12, 2012 = 7:19=20 AM
Subject: [FlyRotary] Re: = Failure of an=20 LS-1 D-580 type ignition coil

This is a different thing entirely.   My = guess is=20 that your mixture is changing at lower MP and raising the = EGT.  =20 Assuming the ignition timing is OK, this is probably what you = want. =20 Higher EGT due to leaner mixture at low power wont hurt anything = within=20 limits.   I don't know the limits of this engine of=20 course.   What does your mixture monitor tell you under = these=20 conditions compared to high throttle?

Tracy

On Sun, Mar 11, 2012 at 10:51 PM, Rob <rob@mum.edu> wrote:
Is this the same thing that happens when = manifold=20 pressure is reduced but RPM is increased, like when I reduce = throttle to go=20 to a lower altitude or for landing? When I do this my EGT starts to = climb to=20 1600 or even 1700 degrees. This in on my Ford V6 with Tracy's EC2 = and=20 EM2.   It dosen't make cents in this case either so it = must be the=20 same phenomenon. Do I need to worry about this climbing EGT or=20 not?
Thanks for any insights?
 
Robert Bollinger
----- Original Message ----- =
From: = Tracy
To: Rotary = motors in=20 aircraft
Sent: Saturday, March 10, = 2012 8:22=20 AM
Subject: [FlyRotary] Re: = Failure of=20 an LS-1 D-580 type ignition coil

The other guys pretty much nailed it.   Less burning in = the=20 chamber 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> = wrote:

On 3/9/2012 10:22 PM, DLOMHEIM@aol.com wrote:=20
Tracy wrote:  >As usual, the in-flight symptom = was a rise=20 in EGT on the affected rotor.
 
Can someone describe the science behind a "rise in EGT" = when we=20 lose a single coil.  I would have expected a drop in EGT = due to=20 less thorough burning of the mixture and therefore excess = un-burnt fuel which I thought would provide cooler temps = of the=20 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=20 space is long and narrow at TDC. If you ignite the fuel air = charge in a=20 rotary at tdc from only one end, the flame front progresses = slowly from=20 one end of the "combustion chamber" to the other. Two plugs (and = coils)=20 for each rotor are present in order to facilitate complete = burning of=20 the fuel-air charge from opposite ends, and to extract as much = power=20 from the charge as possible before the "power stroke" portion of = rotor=20 rotation uncovers an exhaust port and begins the "exhaust=20 stroke"

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

Make Sense?
Dave (a lingering former=20 = rotorhead)
------=_NextPart_000_0019_01CD0041.3C73AAE0--