Return-Path: Received: from [65.54.168.111] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 4.3c2) with ESMTP id 795897 for flyrotary@lancaironline.net; Wed, 16 Mar 2005 09:44:04 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.54.168.111; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Wed, 16 Mar 2005 06:43:18 -0800 Message-ID: Received: from 4.174.2.222 by BAY3-DAV7.phx.gbl with DAV; Wed, 16 Mar 2005 14:43:18 +0000 X-Originating-IP: [4.174.2.222] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: SAG Report Date: Wed, 16 Mar 2005 09:43:15 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0081_01C52A0C.93AA41B0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Wed, 16 Mar 2005 09:43:15 -0500 X-OriginalArrivalTime: 16 Mar 2005 14:43:18.0871 (UTC) FILETIME=[7E7DEE70:01C52A36] This is a multi-part message in MIME format. ------=_NextPart_000_0081_01C52A0C.93AA41B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable It DOES happen in cars. A comment by my brother who drove an American = Mazda 1976 Cosmo is what tipped me off to it many years ago. It happens = after hours at HIGH throttle, which doesn't usually happen much in cars. Tracy I have no doubt that the SAG phenomenon is exactly as described, = caused=20 by as described. I am wondering when I missed the part about it=20 happening in cars or race cars or other applications. I'm given to=20 believe that there are lots of rotarys in boats and such. I've never=20 heard of it happening in anything except airplanes. Are we running a=20 little bit different ignition system? I understand that it seems to=20 have something to do with shrouded plugs, but doesn't anyone else have = this problem with unshrouded plugs? Would a CD ignition or something = of=20 the sort help? At a loss to figure out why aviators seem to be the only victims ... = Jim S. Ed Anderson wrote: > Hi Folks > =20 > Just got back from Florida where spent weekend with Tracy and Laura. = =20 > Tracy and I flew to the Leeward Ranch RV Flyin on Saturday. On the=20 > way there I encountered the worst case of spark plug "SAG" ever. We = > were cruising at 4500 MSL when the old EGT started south dropping = from=20 > around 1650 to below 1400 F. First on the rear rotor then on the=20 > front rotor. Most of the time it only happens on one rotor at a = time=20 > and will frequently go away after a few minutes - not this time. > =20 > I began getting a little concerned when both rotors were in SAG and=20 > seemed content to remain there. I tried backing off the throttle,=20 > switching injector sets on and off with no avail. This had been = going=20 > on for several minutes (longer than normal) when I noticed something = I=20 > had never noticed before - either because the SAG had never remained = > that long on both rotors OR simply had not scan the oil and coolant=20 > temps in previous sags. > =20 > In any case, I was surprised to find the oil at 190F and the coolant = a=20 > 210F when with the OAT and power setting I was carrying they should=20 > have both been around 165-170F. So it clearly looked like the same=20 > symptoms as overly retarded ignition timing. This must have lasted = > approx 15 minutes or more. Finally on let down to the Flying = location=20 > the SAG went away and temps came down. > =20 > So on the ground I took out the sparkplugs and it was clear the=20 > ceramic white center was completely coated in lead/carbon - you = could=20 > see the lead crystal glint in the sun. Both leading and trailing = look=20 > about the same - there was little to no detectable wear on the=20 > electrodes just the ceramic cone black. > =20 > Installed new spark plugs and flew it back to Tracy's and on home=20 > today without further incident.=20 > =20 > Just wanted to pass this on because it can sure cause you to think = you=20 > may have fuel system problems when in reality its the spark plugs -=20 > especially for any of you using Avgas as I do. > =20 > Had a great weekend (as always) with the Crooks and was happy to = join=20 > them both at a birthday dinner for Laura's father on Saturday = evening.=20 > =20 > Best Regards > =20 > Ed > =20 > Ed Anderson > Rv-6A N494BW Rotary Powered > Matthews, NC > eanderson@carolina.rr.com = > >> Homepage: http://www.flyrotary.com/ >> Archive: = http://lancaironline.net/lists/flyrotary/List.html ------=_NextPart_000_0081_01C52A0C.93AA41B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
It DOES happen in cars.  A comment by my brother who = drove an=20 American Mazda 1976 Cosmo is what tipped me off to it many years = ago.  It=20 happens after hours at HIGH throttle, which doesn't usually = happen=20 much in cars.
 
Tracy

I have no doubt that the SAG phenomenon is exactly as=20 described, caused
by as described.  I am wondering when I = missed the=20 part about it
happening in cars or race cars or other = applications. =20 I'm given to
believe that there are lots of rotarys in boats and=20 such.  I've never
heard of it happening in anything except=20 airplanes.  Are we running a
little bit different ignition=20 system?  I understand that it seems to
have something to do = with=20 shrouded plugs, but doesn't anyone else have
this problem with = unshrouded=20 plugs?  Would a CD ignition or something of
the sort = help?

At=20 a loss to figure out why aviators seem to be the only victims ... Jim=20 S.

Ed Anderson wrote:

> Hi Folks
>  =
> Just=20 got back from Florida where spent weekend with Tracy and Laura.  =
>=20 Tracy and I flew to the Leeward Ranch RV Flyin on Saturday.  On = the=20
> way there I encountered the worst case of spark plug "SAG"=20 ever.  We
> were cruising at 4500 MSL when the old EGT = started=20 south dropping from
> around 1650 to below 1400 F.  First = on the=20 rear rotor then on the
> front rotor.  Most of the time it = only=20 happens on one rotor at a time
> and will frequently go away = after a=20 few minutes  - not this time.
> 
> I began = getting a=20 little concerned when both rotors were in SAG and
> seemed = content to=20 remain there.  I tried backing off the throttle,
> = switching=20 injector sets on and off with no avail.  This had been going =
> on=20 for several minutes (longer than normal) when I noticed something I =
>=20 had never noticed before - either because the SAG had never remained =
>=20 that long on both rotors OR simply had not scan the oil and coolant =
>=20 temps in previous sags.
> 
> In any case, I was = surprised to=20 find the oil at 190F and the coolant a
> 210F when with the OAT = and=20 power setting I was carrying they should
> have both been = around=20 165-170F.  So it clearly looked like the same
> symptoms = as overly=20 retarded ignition timing.   This must have lasted
> = approx 15=20 minutes or more.  Finally on let down to the Flying location =
> the=20 SAG went away and temps came down.
> 
> So on the = ground I=20 took out the sparkplugs and it was clear the
> ceramic white = center was=20 completely coated in lead/carbon - you could
> see the lead = crystal=20 glint in the sun.  Both leading and trailing look
> about = the same=20 - there was little to no detectable wear on the
> electrodes = just the=20 ceramic cone black.
> 
> Installed new spark plugs = and flew=20 it back to Tracy's and on home
> today without further = incident.=20
> 
> Just wanted to pass this on because it can = sure cause=20 you to think you
> may have fuel system problems when in = reality its=20 the spark plugs -
> especially for any of you using Avgas as I=20 do.
> 
> Had a great weekend (as always) with the = Crooks and=20 was happy to join
> them both at a birthday dinner for Laura's = father=20 on Saturday evening.
> 
> Best = Regards
> =20
> Ed
> 
> Ed Anderson
> Rv-6A N494BW = Rotary=20 Powered
> Matthews, NC
> eanderson@carolina.rr.com = <mailto:eanderson@carolina.rr.co= m>


>> =20 Homepage:  http://www.flyrotary.com/
>&= gt; =20 Archive:   http://lancai= ronline.net/lists/flyrotary/List.html
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