X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from cdptpa-omtalb.mail.rr.com ([75.180.132.120] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with ESMTP id 4488937 for flyrotary@lancaironline.net; Fri, 01 Oct 2010 09:07:50 -0400 Received-SPF: pass receiver=logan.com; client-ip=75.180.132.120; envelope-from=eanderson@carolina.rr.com Return-Path: X-Authority-Analysis: v=1.1 cv=Kw91eHCEomHy3ia4iliyYwPDdG6gmL57yW58Q85fxVk= c=1 sm=0 a=HzuiwmCV-AYA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:17 a=ayC55rCoAAAA:8 a=BcFp16ZBAAAA:8 a=arxwEM4EAAAA:8 a=r1ClD_H3AAAA:8 a=8Aa1Lm30AuVkPCVF9WMA:9 a=IrrCkEXvow7U0B0D4nYA:7 a=1lrPglKBuZuiAIphLCjki3Up0oEA:4 a=wPNLvfGTeEIA:10 a=4i9ixV_N-6EA:10 a=Ia-xEzejAAAA:8 a=17n_08jnAAAA:8 a=4LHuVIoBCfJHntNWXnsA:9 a=OA9VGHXgU-btOp42370A:7 a=N38HPxSYWGyQEZew-x5bv85afMwA:4 a=EzXvWhQp4_cA:10 a=rPkcCx1H5rrOSfN0dPC7kw==:117 X-Cloudmark-Score: 0 X-Originating-IP: 174.110.167.5 Received: from [174.110.167.5] ([174.110.167.5:50103] helo=EdPC) by cdptpa-oedge04.mail.rr.com (envelope-from ) (ecelerity 2.2.2.39 r()) with ESMTP id 93/24-28816-10DD5AC4; Fri, 01 Oct 2010 13:07:14 +0000 Message-ID: <88F3277EC6544AA99ED173524CFFD57F@EdPC> From: "Ed Anderson" To: "Rotary motors in aircraft" References: In-Reply-To: Subject: Re: [FlyRotary] lead fouled plugs Date: Fri, 1 Oct 2010 09:07:00 -0400 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0089_01CB6148.01C5C930" X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 This is a multi-part message in MIME format. ------=_NextPart_000_0089_01CB6148.01C5C930 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hi Steve, No problem, all appreciate the new perspective you have brought to the = topic of SAG and the hours and money you have invested. I think this = type of discussion greatly helps educate us all in whatever topic is = being discussed. Heck, sometimes we even figure out what the problem = really is which is always a plus {:>) I got to thinking about the rise in Coolant and Oil temps - which does = support the detonation part of your theory, and I wonder whether there = is an alternate explanation since few if any seem to find evidence of = detonation - even on the plugs.=20 I may be one of the few flyers that have actually experience detonation = with an N/A 13B. I am 90% confident it was detonation based on the = following: 1. I inadvertently set my ignition static timing to 45 Deg BTDC (well, = you don't think I would do it on purpose, do you? {:>)) and went flying 2. In those days, I couldn't get much above 5000 RPM until after take = off 3. After airborne I decided to do a WOT run - within 5 -10 seconds after = opening the throttle, I noticed the exhaust note changed from its = usually roar to a clearly staccato Popping sound. I listened to it = perhaps 10-20 seconds before deciding that something was decidedly = different and retarded the throttle. Landed and took the sparkplugs out. The conditions of my plugs after experiencing detonation were appalling. = =20 The leading spark plugs were destroyed. The heavy ground electrode had = eroded almost back to the wall, the center electrode had receded approx = 1/8" and the ceramic cone was missing. Yes, as in GONE back down at = least 1" into the plug. =20 The trailing plugs were less damaged but electrode erosion was clear = and the ceramic cone on one was cracked and the second trailing plug had = a chip missing from the cone. As best I could determine there was no = damage to the engine, but that may have occurred had I not retarded the = throttle after the short duration in detonation. Unfortunately, I was not monitoring the temps so have no additional = evidence that the engine was in detonation - but give the condition of = the spark plugs and the popping exhaust, I am convinced it was = detonation. I know when I disable the leading plugs and just run the engine on the = trailing plugs my EGT climbs above 1700F whereas it is normally between = 1500-1600F. I suppose this is because less fuel is being burnt in the = combustion chamber and more burning in the exhaust header. Next time I = fly, I'll disable the trailing plugs and note the coolant/oil temps and = then try it with the trailing plugs disabled and see what the = temperature conditions are flying on just the leading plugs. The = objective is to see how much (if any) the running on only one set of the = pair effects coolant/oil temps under normal (non-SAG) conditions. Ed From: Steven W. Boese=20 Sent: Thursday, September 30, 2010 10:29 PM To: Rotary motors in aircraft=20 Subject: [FlyRotary] lead fouled plugs The following is an exchange between Ed and me earlier today. I hope Ed = doesn't mind my forwarding it to the list. For some reason, my replies to the list are unreasonably large and = cannot be read (at least by me) in the archives. I hope that I'm not = distributing a virus and that creating new messages instead of simply = replying works OK. It has occurred to me that it may be possible to initiate SAG by going = to a hotter plug instead of waiting for a used one to malfunction. If I = can do this with the engine on the test stand, that may enable studying = the SAG phenomenon with less risk (to me- not necessarily the engine). = A starting point may be using stock leading plugs (BUR7EQ) in all four = locations. Steve Boese Ed and all, The replacement colder plugs I thought I'd try are: 11524-NGK Spark Plug<br>BR10EIX Racing @ 9.44 as copied from the order to Racing Beat. As I mentioned in the talk at Paducah, I tried all sorts of chemical = cleaning methods and the lead remained on the insulator. My thought is = that the lead may be incorporated into a glass type of phase that has = significantly less thermal conductivity than the alumina insulator. I = agree that the fact that the room temperature resistance of the material = on the insulator being over 10 raised to the 13th power ohms with the = connecting points as close as possible (about 0.030" apart) does not = mean that the material does not become conductive at higher = temperatures. The fact that the EGT drops and the coolant and oil temperatures rise = during SAG whereas the EGT rises and the coolant and oil temperatures = drop when disabling either the leading or trailing ignition coil = suggests to me that SAG is not a result of the spark plug misfiring. I have not seen the kind of damage to my spark plugs that the photo of = the pre-ignition shows either. Alternative explanations for the observations are more than welcome and = I am willing to try to test these alternatives as much as I am able and = encourage others to do the same within the limits of acceptable risk. I = have no personal investment in one theory over another, but am just = interested in understanding what is going on. Steve Boese -------------------------------------------------------------------------= ------- From: Ed Anderson [eanderson@carolina.rr.com] Sent: Thursday, September 30, 2010 11:39 AM To: Steven W. Boese Subject: Lead Fouled Plugs Hi Steve, Was looking into colder plugs myself and came up on this at the Champion = SP site http://www.championsparkplugs.com/sparkplug411.asp?kw=3DLead+Fouling&mfid= =3D2 Lead fouling can be difficult to diagnose. Although it usually appears = as yellowish brown deposits on the insulator nose, some fuel additives = may also cause similar discoloration (and are harmless). Also, a fouled = plug can typically be detected with a simple resistance tester, whereas = a lead fouled plug will read within specs (while at room temperature). = Also, the ease of fouling will vary on different engines even with the = same lead exposure; this is because lead compounds combine at different = temperatures. Those formed at 370-470=B0C (700-790=B0F) having the = greatest likelihood of causing lead resistance (fouling) on a plug. I thought this was interesting , I know you attempted to measure the = resistance of the Lead coating. It appears (if I read this correctly) = that while normally (carbon?) fouled plugs will give you a lower = resistance reading, it appears that Lead fouled plugs will give a normal = resistance reading at room temperature. So apparently the lead = conduction (fouling) must take place at elevated (running ) = temperatures. Just thought I would throw it in the hopper {:>). Here is a photo of what they say a pre-ignition plug looks like - My = plugs never looked like that except for the one time during first 60 = hours of flight when I inadvertently set the static ignition timing to = 45 Deg BTDC. Sagged plugs never approach this condition in my = experience. Ed =20 plug damaged due to Sustained pre-Ignition=20 Ed Edward L. Anderson Anderson Electronic Enterprises LLC 305 Reefton Road Weddington, NC 28104 http://www.andersonee.com http://www.eicommander.com ------=_NextPart_000_0089_01CB6148.01C5C930 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hi Steve,
 
No problem, all appreciate the new perspective = you have=20 brought to the topic of SAG and the hours and money you have = invested.  I=20 think this type of discussion greatly helps educate us all in whatever = topic is=20 being discussed.  Heck, sometimes we even figure out what the = problem=20 really is which is always a plus {:>)
 
I got to thinking about the rise in Coolant and = Oil temps=20 - which does support the detonation part of your theory, and I wonder = whether=20 there is an alternate explanation since few if any seem to find evidence = of=20 detonation - even on the plugs. 
 
 I may be one of the few flyers that have = actually=20 experience detonation with an N/A 13B.  I am 90% confident it was=20 detonation based on the following:
 
1.  I inadvertently set my ignition static = timing to=20 45 Deg BTDC (well, you don't think I would do it on purpose, do you? = {:>))=20 and went flying
2. In those days, I couldn't get much above 5000 = RPM until=20 after take off
3. After airborne I decided to do a WOT run - = within 5 -10=20 seconds after opening the throttle, I noticed the exhaust note changed = from its=20 usually roar to a clearly staccato Popping sound.  I listened to it = perhaps=20 10-20 seconds before deciding that something was decidedly different and = retarded the throttle. Landed and took the sparkplugs out.
 
The conditions of my plugs after experiencing = detonation=20 were appalling. 
 
The leading spark plugs were destroyed.  = The heavy=20 ground electrode had eroded almost back to the wall, the center = electrode had=20 receded approx 1/8" and the ceramic cone was missing. Yes, as in GONE = back down=20 at least 1" into the plug.  
 
 The trailing plugs were less damaged but = electrode=20 erosion was clear and the ceramic cone on one was cracked and the second = trailing plug had a chip missing from the cone.  As best I could = determine=20 there was no damage to the engine, but that may have occurred had I not = retarded=20 the throttle after the short duration in detonation.
 
Unfortunately, I was not monitoring the temps so = have no=20 additional evidence that the engine was in detonation - but give the = condition=20 of the spark plugs and the popping exhaust, I am convinced it was=20 detonation.
 
 I know when I disable the leading plugs = and just run=20 the engine on the trailing plugs my EGT climbs above 1700F whereas it is = normally between 1500-1600F.  I suppose this is because less fuel = is being=20 burnt in the combustion chamber and more burning in the exhaust = header. =20 Next time I fly, I'll disable the trailing plugs and note  the = coolant/oil=20 temps and then try it with the trailing plugs disabled and see what the=20 temperature conditions are flying on just the leading plugs.  The = objective=20 is to see how much (if any) the running on only one set of the pair = effects=20 coolant/oil temps under normal (non-SAG) conditions.
 
Ed
 
 
From: Steven W. Boese
Sent: Thursday, September 30, 2010 10:29 PM
Subject: [FlyRotary] lead fouled plugs

The following is an exchange between Ed and me earlier = today.  I=20 hope Ed doesn't mind my forwarding it to the list.
 
For some reason, my replies to the list are = unreasonably=20 large and cannot be read (at least by me) in the archives.  I hope = that I'm=20 not distributing a virus and that creating new messages instead of = simply=20 replying works OK.
 
It has occurred to me that it may be possible = to initiate=20 SAG by going to a hotter plug instead of waiting for a used one to=20 malfunction.  If I can do this with the engine on the test = stand, that=20 may enable studying the SAG phenomenon with less risk (to me- not = necessarily=20 the engine).  A starting point may be using stock leading plugs = (BUR7EQ) in=20 all four locations.
 
Steve Boese
 
Ed and all,
 
The replacement colder plugs I thought = I'd try=20 are:
 
11524-NGK Spark Plug&lt;br&gt;BR10EIX Racing @=20 9.44
 
as copied = from the order to=20 Racing Beat.
 
As I mentioned in the talk = at Paducah, I=20 tried all sorts of chemical cleaning methods and the lead remained on = the=20 insulator.  My thought is that the lead may=20 be incorporated into a glass type of phase that = has=20 significantly less thermal conductivity than the alumina = insulator.  I=20 agree that the fact that the room temperature resistance of the material = on the=20 insulator being over 10 raised to the 13th power ohms with the = connecting points=20 as close as possible (about 0.030" apart)  does not mean that the = material=20 does not become conductive at higher temperatures.
 
The fact that = the EGT drops=20 and the coolant and oil temperatures rise during SAG whereas=20 the EGT rises and the coolant and oil temperatures drop when = disabling either the leading or trailing ignition coil suggests to = me=20 that SAG is not a result of the spark plug misfiring.
 
I have not seen = the kind of damage to=20 my spark plugs that the photo of the pre-ignition shows=20 either.
 
Alternative explanations for = the=20 observations are more than welcome and I am willing to try to test these = alternatives as much as I am able and encourage others to do the same = within the=20 limits of acceptable risk.  I have no personal investment in one = theory=20 over another, but am just interested in understanding what is going=20 on.
 
Steve Boese
 
 
From: Ed Anderson=20 [eanderson@carolina.rr.com]
Sent: Thursday, September 30, 2010 = 11:39=20 AM
To: Steven W. Boese
Subject: Lead Fouled=20 Plugs

Hi Steve,
 
Was looking into colder plugs myself and came up = on this=20 at the Champion SP site
http://www.championsparkplugs.com/sparkplug411.asp?kw=3DL= ead+Fouling&mfid=3D2
 
Lead fouling can be difficult to diagnose. Although it = usually=20 appears as yellowish brown deposits on the insulator nose, some fuel additives = may also=20 cause similar discoloration (and are harmless). Also, a fouled plug can=20 typically be detected with a simple resistance tester, whereas a lead fouled plug will read within = specs=20 (while at room temperature). Also, the ease of fouling will vary on different engines even with the = same lead=20 exposure; this is because lead compounds combine at different = temperatures.=20 Those formed at 370-470=B0C (700-790=B0F) having the greatest likelihood = of causing=20 lead resistance (fouling) on a plug.
 
I thought this was interesting ,  I = know=20 you attempted to measure  the resistance of the Lead = coating.  It=20 appears (if I read this correctly) that while normally (carbon?) fouled = plugs=20 will give you a lower resistance reading, it appears that Lead fouled = plugs will=20 give a normal resistance reading at room temperature.  So = apparently the=20 lead conduction (fouling) must take place at elevated (running )=20 temperatures.  Just thought I would throw it in the hopper=20 {:>).
 
Here is a photo of what they say a pre-ignition = plug looks=20 like - My plugs never looked like that except for the one time during = first 60=20 hours of flight when I inadvertently set the static ignition timing to = 45 Deg=20 BTDC.  Sagged plugs never approach this condition in my=20 experience.
 
Ed
plug damaged due to Sustained=20 = pre-Ignition
 
 
Ed
 
Edward L. Anderson
Anderson Electronic = Enterprises=20 LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.com
http://www.eicommander.com
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