Return-Path: Received: from [24.25.9.103] (HELO ms-smtp-04-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 4.3c2) with ESMTP id 791781 for flyrotary@lancaironline.net; Sun, 13 Mar 2005 19:06:00 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.103; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-185-127.carolina.rr.com [24.74.185.127]) by ms-smtp-04-eri0.southeast.rr.com (8.12.10/8.12.7) with SMTP id j2E04vCi022415 for ; Sun, 13 Mar 2005 19:05:02 -0500 (EST) Message-ID: <001001c52829$76c29140$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" Subject: SAG Report Date: Sun, 13 Mar 2005 19:04:55 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000B_01C527FF.8B6FF080" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2800.1106 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_000B_01C527FF.8B6FF080 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Folks Just got back from Florida where spent weekend with Tracy and Laura. = Tracy and I flew to the Leeward Ranch RV Flyin on Saturday. On the 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 around = 1650 to below 1400 F. First on the rear rotor then on the front rotor. = Most of the time it only happens on one rotor at a time and will = frequently go away after a few minutes - not this time. I began getting a little concerned when both rotors were in SAG and = seemed content to remain there. I tried backing off the throttle, = switching injector sets on and off with no avail. This had been going = on for several minutes (longer than normal) when I noticed something I = 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 = temps in previous sags. In any case, I was surprised to find the oil at 190F and the coolant a = 210F when with the OAT and power setting I was carrying they should have = both been around 165-170F. So it clearly looked like the same symptoms = as overly retarded ignition timing. This must have lasted approx 15 = minutes or more. Finally on let down to the Flying location the SAG = went away and temps came down. So on the ground I took out the sparkplugs and it was clear the ceramic = white center was completely coated in lead/carbon - you could see the = lead crystal glint in the sun. Both leading and trailing look about the = same - there was little to no detectable wear on the electrodes just the = ceramic cone black. Installed new spark plugs and flew it back to Tracy's and on home today = without further incident. =20 Just wanted to pass this on because it can sure cause you to think you = may have fuel system problems when in reality its the spark plugs - = especially for any of you using Avgas as I do. Had a great weekend (as always) with the Crooks and was happy to join = them both at a birthday dinner for Laura's father on Saturday evening. =20 Best Regards Ed Ed Anderson Rv-6A N494BW Rotary Powered Matthews, NC eanderson@carolina.rr.com ------=_NextPart_000_000B_01C527FF.8B6FF080 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Folks
 
Just got back from Florida where spent = weekend with=20 Tracy and Laura.  Tracy and I flew to the Leeward Ranch RV Flyin on = Saturday.  On the way there I encountered the worst case of spark = plug=20 "SAG" ever.  We were cruising at 4500 MSL when the old EGT started = south=20 dropping from around 1650 to below 1400 F.  First on the rear rotor = then on=20 the 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=20 time.
 
I began getting a little concerned when = both rotors=20 were in SAG and seemed content to remain there.  I tried backing = off the=20 throttle, switching injector sets on and off with no avail.  This = had been=20 going on for several minutes (longer than normal) when I noticed = something I had=20 never noticed before - either because the SAG had never remained that = long on=20 both rotors OR simply had not scan the oil and coolant temps in previous = sags.
 
In any case, I was surprised to find = the oil at=20 190F and the coolant a 210F when with the OAT and power setting I was = carrying=20 they should have both been around 165-170F.  So it clearly looked = like the=20 same symptoms as overly retarded ignition timing.   This must = have=20 lasted approx 15 minutes or more.  Finally on let down to the = Flying=20 location the SAG went away and temps came down.
 
So on the ground I took out the = sparkplugs and it=20 was clear the ceramic white center was completely coated in lead/carbon = - you=20 could see the lead crystal glint in the sun.  Both leading and = trailing=20 look about the same - there was little to no detectable wear on the = electrodes=20 just the ceramic cone black.
 
Installed new spark plugs and flew it = back to=20 Tracy's and on home today without further incident. 
 
Just wanted to pass this on because it = can sure=20 cause you to think you may have fuel system problems when in reality its = the=20 spark plugs - especially for any of you using Avgas as I = 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 on = Saturday=20 evening. 
 
Best Regards
 
Ed
 
Ed Anderson
Rv-6A N494BW Rotary=20 Powered
Matthews, NC
eanderson@carolina.rr.com
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