X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sun, 01 Jun 2008 08:47:33 -0400 Message-ID: X-Original-Return-Path: Received: from sfa.gami.com ([68.89.254.162] verified) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2947183 for lml@lancaironline.net; Sat, 31 May 2008 10:33:38 -0400 Received-SPF: none receiver=logan.com; client-ip=68.89.254.162; envelope-from=gwbraly@gami.com Received: from localhost (localhost.localdomain [127.0.0.1]) by sfa.gami.com (Postfix) with ESMTP id 7073729C076 for ; Sat, 31 May 2008 09:33:01 -0500 (CDT) Received: from gamimail1.Gami.local (unknown [10.10.10.33]) by sfa.gami.com (Postfix) with ESMTP id EF1FF29C073 for ; Sat, 31 May 2008 09:33:00 -0500 (CDT) Received: from gamimail1.Gami.local ([10.10.10.33]) by gamimail1.Gami.local ([10.10.10.33]) with mapi; Sat, 31 May 2008 09:32:58 -0500 From: George Braly X-Original-To: Lancair Mailing List X-Original-Date: Sat, 31 May 2008 09:32:50 -0500 Subject: RE: [LML] Re: Electronic ignition spark plugs Thread-Topic: [LML] Re: Electronic ignition spark plugs Thread-Index: AcjDJpmvnxYJeExjSoeVItD1ei38ygAAsheA X-Original-Message-ID: References: In-Reply-To: Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: acceptlanguage: en-US Content-Type: multipart/alternative; boundary="_000_C273A1B35F3C6748B52EE0CC2FCEE96C6DE070EC15gamimail1Gami_" MIME-Version: 1.0 X-Virus-Scanned: by amavisd-new-2.3.2 (20050629) (Debian) at gami.com --_000_C273A1B35F3C6748B52EE0CC2FCEE96C6DE070EC15gamimail1Gami_ Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: quoted-printable >>So, when we talk about 'anecdotal' information, it seems to me that the r= eports linking engine damage and auto spark plugs is the true anecdotal inf= ormation.<< Except that the failures are not, at least from my perspective, anecdotal.= Good engine shops with whom I do business every day have seen the problem= engines - - and have changed their conduct accordingly - ie, refuse to bu= ild engines for EI/automotive plug installations. I have seen enough of t= he evidence to be satisfied there is a real problem. But leaving that aside, your comment that: " Still, there are many auto pl= ug installations that run just fine" goes to the heart of the matter. In aviation - - a lot of things "work" or "run" just find as long as = and so long as they operate in the "center" of the operating envelope. Th= e problems always happen when airplanes or engines are required to operate = at the edge or boundary of the envelope. (Think of O- rings and 32d F OAT= 's and the Challenger disaster). And nobody knows where the boundary of the envelope is with respect to auto= motive plugs (and even as to where it is with respect to WHICH brand, make,= or model of automotive plug). When you say "... that still is not evidence or proof that they should not = be used." you have, in my judgment, reveresed the question from its prope= r form. The question about components in aviation should never, in my judgment, be= : "does anybody have any evidence to show the [component] is 'bad'" . Rather the question should be: "... does anybody have the data to show tha= t these spark plugs will work competently and free of pre-ignition across t= he known anticipated operating envelope of the engines into which they are = to be inserted." Regards, George ________________________________ From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Chuc= k Jensen Sent: Saturday, May 31, 2008 9:00 AM To: lml@lancaironline.net Subject: [LML] Re: Electronic ignition spark plugs George, I appreciate what you are saying (and especially appreciate of the engine-e= ducation that your company has done, particularly in the area of LOP operat= ions). Still, there are many auto plug installations that run just fine. = I don't find this more than a simple reliance on hope. There is no empiric= al evidence that auto plugs are not up to the task, at least for most GA ap= plications. You advise that you don't know what temp that auto plugs run a= t and whether it is within their design range. So, when we talk about 'ane= cdotal' information, it seems to me that the reports linking engine damage = and auto spark plugs is the true anecdotal information. Engine damage caused by pre-ignition (unrelated to the plug), mis-timing or= simple bad-luck with failure of a mechanical component at the same time th= at an auto plug was near-by, is equally, or even more likely, the cause of = the damage rather than the presence of the auto plug. I'm sure you would a= gree that guilt by association doesn't work for crime or mechanical failure= . In short, there still seems to be a lack of information, data or proof that= auto plugs, when used in similar applications to those already proven, do = not present an elevated, quantified risk, though it is your considered opin= ion (not to be dismissed out of hand) that it is not a good idea. With tha= t said and as stated before, I fly aviation plugs and would recommend them = to anyone that asked, but that still is not evidence or proof that they sho= uld not be used. Chuck Jensen -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net]On Behalf Of Georg= e Braly Sent: Saturday, May 31, 2008 9:22 AM To: lml@lancaironline.net Subject: [LML] Re: Electronic ignition spark plugs Chuck, I'm sorry if my posting was disappointing. But I tried to make sure it was factual and informative. It may not be he= lpful - - for those that want to go ahead and hope that the automtoive plu= gs will work in their application. I am NOT asserting that the automotive splugs are, in fact, unsatisfactory. What I AM asserting is that unless someone has meaesured the actual temper= ature of the ceramic in the automotive plug inserted into the aircraft air = cooled cylinder then the people using the automotive spark plug are relying= on "hope as a method" to establish safety for the configuration of their e= ngines. Given that there are apparently reliable reports of pre-ignition with the = use of automotive spark plugs in common aircraft engines - - then there is = hard evidence that the heat range of the plugs is marginal at best and unsu= itable in at least some portions of the normal operating envelope. >> What is it about auto plugs that are inadequate? Peak temp tolerance? = Temp rate of change? Cylinder compression? 100LL gas? Where do they fal= l short, ...<< I don't know where they fall short in any or all of the areas about which y= ou inquire. But none of those are the one about which I am most concerned. The operating temperature of the spark plug ceramic under hot day high powe= r conditions across the full range of allowable combustion A/F ratios is th= e first area of concern. If it doesn't qualify there - - then nothing else= matters. And so far as I can tell - - nobody in the experimental aircraft world know= s the answer to that question. They may be just fine and run along at a c= ool 1200d F. Or not. But everybody keeps hoping "yes" but nobody knows and= nobody has the data. I assume that you agree that hope should not be a me= thod of assurance for safety critical items in aircraft. The fact that some people have run automotive plugs successfully in some en= gines - - is a lot like saying that some people have successfully used car= gas in their aircraft engine. Unless you know that they have used that gasoline under the worst case cond= itions that YOU will ever encounter with your engine and that your engine i= s "less critical or the same" as the engine that someone else used - - and = that when you buy your automotive gas from your local dealer that it will b= e the same or equivelent gas bought from the earlier supplier for the earli= er test - - - then you really are just following the "hope as a method" co= ncept for assuring that your use of similar car gasoline would work in you= r particular application. I can go out and run a 350 Hp Navajo Chieftan turbocharged engine all day a= t 210 Hp and do it on premium car gas. But if I try to run it at 230 Hp on a hot day with hot cylinders in a singl= e engine climb - - it is going to detonate. Or if I try to run it at 270 Hp on any day, it is going to detonate. But if I just told people that " I have run a TIO-540J2Bd engine on car gas= " - - - then it is likely that someone else will decide to follow the "hop= e as a method" concept and try the same thing - - with disasterous results. I know what the actual heat range for the aircraft plugs is in the high per= formance aircraft engine and the temperature margins that are present. But if I were to insert an automotive plug into a bushing screwed into the = cylinder head of my air cooled aircraft engine I would have to merely "= hope" that it was going to work based on a mixed set of anecdotal testimon= ials about their successful and unsuccessful use in aircraft engines report= ed by others. That is all I am saying. Hope is not really a method. Regards, George ________________________________ From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Chuc= k Jensen Sent: Friday, May 30, 2008 6:06 PM To: lml@lancaironline.net Subject: [LML] Re: Electronic ignition spark plugs George, Your postings are quite surprising, and a bit disappointing. You point out= that auto plugs are different that aviation plugs. You point out that you= know the temperature of the aviation plugs during operations. You point o= ut that auto plugs enjoys a heat sunk environment. You point out that the = aviation plug was designed for the aviation environment. All of these are true, but unfortunately, you leave us to 'conclude' that t= hat somehow means that the auto plug are unsatisfactory in the aviation env= ironment. I don't like having to bridge such gaps in data. What is it ab= out auto plugs that are inadequate? Peak temp tolerance? Temp rate of cha= nge? Cylinder compression? 100LL gas? Where do they fall short, other th= an they are 'different' from aviation plugs? Personally, I run aviation plugs on both my mag and EI, but many have run a= uto plugs without problems. Why, or how, were they successful when there a= re so many implied deficiencies with auto plugs? Thanks, Chuck Jensen -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net]On Behalf Of Georg= e Braly Sent: Friday, May 30, 2008 9:45 AM To: lml@lancaironline.net Subject: [LML] Re: Electronic ignition spark plugs Colyn, Other than curiosity - - it is not, frankly, important that I know what t= he number is supposed to be - - What is important is that nobody has a clue as to what the number is for th= e automotive spark plug mounted in the aircraft application. Keep in mind that the automotive spark plug enjoyes being "heat sunk" into= a massive water cooled cylinder head that is held at constant temperature = from a thermostat. By contrast, the aircraft spark plug is desgined for the much more variable= environment of the air cooled cylinder head which can have temperatures mo= re than twice as high as the automotive cylinder head. There is a casual acceptance of a substantial level of "under-investigati= on" that is associated with some of these often routinely accepted recomm= endations to use components that have not undergone thoughtful testing at= the boundary conditions of realistic operating environments. Regards, George PS> The answer to your question is in some of the APS class materials. We= made a power point slide that detailed the aircraft spark plug ceramic tem= perature as a function of A/F ratio. ________________________________ From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of Coly= n Case at earthlink Sent: Wednesday, May 28, 2008 9:37 PM To: lml@lancaironline.net Subject: [LML] Re: Electronic ignition spark plugs George said I can tell you the answer to that question with respect to an aviation spar= k plug. okay, what's the answer? say, 50 dF LOP 32" TSIO-550 ....or whatever you ac= tually have. --_000_C273A1B35F3C6748B52EE0CC2FCEE96C6DE070EC15gamimail1Gami_ Content-Type: text/html; charset="us-ascii" Content-Transfer-Encoding: quoted-printable
>>So, when we talk about 'anecdotal' infor= mation,=20 it seems to me that the reports linking engine damage and auto spark plugs = is=20 the true anecdotal information.<<
 
Except that the failures are not, at least from = my=20 perspective,  anecdotal.  Good engine shops with whom I do busine= ss=20 every day have seen the problem engines - - and have changed their conduct= =20 accordingly -  ie, refuse to build engines for EI/automotive plug=20 installations.   I have seen enough of the evidence to be satisfi= ed=20 there is a real problem.
 
But leaving that aside,  your comment that:= "=20 Still, there are many auto plug installations that run just fine" &nbs= p;=20 goes to the heart of the matter.
 
In aviation - -   a  lot of thing= s=20 "work"  or  "run"  just find as long as and so long as they= =20 operate in the "center" of the operating envelope.   The pro= blems=20 always happen when airplanes or engines are required to operate at the= edge=20 or boundary of the envelope.   (Think of O- rings and 32d F OAT's= and=20 the Challenger disaster).
 
And nobody knows where the boundary of the envel= ope is=20 with respect to automotive plugs (and even as to where it is with respect t= o=20 WHICH brand, make, or model of automotive plug).
 
When you say "... that still is not evidence or = proof=20 that they should not be used."  you have,  in my judgment, revere= sed=20 the question from its proper form.
 
The question about components in aviation should= never,=20 in my judgment,  be:  "does anybody have any evidence t= o=20 show the [component] is  'bad'" .  <= /DIV>
 
Rather the question should be:  "... does a= nybody=20 have the data to show that these spark plugs will work competently = and=20 free of pre-ignition across the known anticipated operating envelo= pe of=20 the engines into which they are to be inserted."  <= /DIV>
 
Regards,  George

From: Lancair Mailing List=20 [mailto:lml@lancaironline.net] On Behalf Of Chuck Jensen
Sent:= =20 Saturday, May 31, 2008 9:00 AM
To:=20 lml@lancaironline.net
Subject: [LML] Re: Electronic ignition spar= k=20 plugs

George,
 
I=20 appreciate what you are saying (and especially appreciate of the=20 engine-education that your company has done, particularly in the area = of=20 LOP operations).  Still, there are many auto plug installations that r= un=20 just fine.  I don't find this more than a simple reliance on= =20 hope.  There is no empirical evidence that auto plugs are not up = to=20 the task, at least for most GA applications.  You advise that you= =20 don't know what temp that auto plugs run at and whether it is wit= hin=20 their design range.  So, when we talk about 'anecdotal' information, i= t=20 seems to me that the reports linking engine damage and auto spark plugs is = the=20 true anecdotal information.
 
Engine=20 damage caused by pre-ignition (unrelated to the plug), mis-timing or s= imple=20 bad-luck with failure of a mechanical component at the same time that an au= to=20 plug was near-by, is equally, or even more likely, the cause of the damage= =20 rather than the presence of the auto plug.  I'm sure you would agree t= hat=20 guilt by association doesn't work for crime or mechanical=20 failure.
 
In=20 short, there still seems to be a lack of information, data or proof th= at=20 auto plugs, when used in similar applications to those already pr= oven,=20 do not present an elevated, quantified risk, though it is your considered=20 opinion (not to be dismissed out of hand) that it is not a good idea. = With=20 that said and as stated before, I fly aviation plugs and would recommend th= em to=20 anyone that asked, but that still is not evidence or proof that they should= not=20 be used.
 
Chuck Jensen= =20

 

-----Original Message-----
From: Lancair Mailing List= =20 [mailto:lml@lancaironline.net]On Behalf Of George Braly
Sent= :=20 Saturday, May 31, 2008 9:22 AM
To:=20 lml@lancaironline.net
Subject: [LML] Re: Electronic ignition sp= ark=20 plugs

 
 
Chuck,
 
I'm sorry if my posting was=20 disappointing.
 
But I tried to make sure it was factual and=20 informative.   It may not be helpful - -  for those that w= ant=20 to go ahead and hope that the automtoive plugs will work in their=20 application.
 
I am NOT asserting that the automotive splugs ar= e, in=20 fact, unsatisfactory. 
 
What I  AM asserting is that unless someone= has=20 meaesured the actual temperature of the ceramic in the automotive plug=20 inserted into the aircraft air cooled cylinder then the people using the= =20 automotive spark plug are relying on "hope as a method" = to=20 establish safety for the configuration of their engines.
 
Given that there are apparently reliable reports= of =20 pre-ignition with the use of automotive spark plugs in common aircraft en= gines=20 - - then there is hard evidence that the heat range of the plugs is margi= nal=20 at best and unsuitable in at least some portions of the normal operating= =20 envelope.
 
>> What  is it about auto plugs that = are=20 inadequate?  Peak temp tolerance?  Temp rate of change? =20 Cylinder compression?  100LL gas?  Where do they fall short,=20 ...<<
 
I don't know where they fall short in any or all= of the=20 areas about which you inquire.  But none of those are the one about = which=20 I am most concerned.
 
The operating temperature of the spark plug cera= mic under=20 hot day high power conditions across the full range of allowable combusti= on=20 A/F ratios is the first area of concern.  If it doesn't qualify ther= e - -=20 then nothing else matters.
 
And so far as I can tell - - nobody in the exper= imental=20 aircraft world knows the answer to that question.   They may be= just=20 fine and run along at a cool 1200d F.  Or not. But everybody keeps h= oping=20 "yes" but nobody knows and nobody has the data.  I assume that you a= gree=20 that hope should not be a method of assurance for safety critical it= ems=20 in aircraft.
 
 
The fact that some people have run automotive pl= ugs=20 successfully in some engines - -  is a lot like saying that some peo= ple=20 have successfully used car gas in their aircraft engine.
 
Unless you know that they have used that gasolin= e under=20 the worst case conditions that YOU will ever encounter with your engine a= nd=20 that your engine is "less critical or the same" as the engine that someon= e=20 else used - - and that when you buy your automotive gas from your local d= ealer=20 that it will be the same or equivelent gas bought from the earlier=20 supplier for the earlier test - - -  then you really are just follow= ing=20 the "hope as a method" concept for assuring that your use of similar car= =20 gasoline would  work in your particular application.
 
I can go out and run a 350 Hp Navajo Chieft= an=20 turbocharged engine all day at 210 Hp and do it on premium car=20 gas.  
 
But if I try to run it at 230 Hp on a hot day wi= th hot=20 cylinders in a single engine climb - - it is going to=20 detonate.
 
Or if I try to run it at 270 Hp on any day, it i= s going=20 to detonate.
 
But if I just told people that " I have run a TI= O-540J2Bd=20 engine on car gas" - - -  then it is likely that someone else will d= ecide=20 to follow the "hope as a method" concept and try the same thing - - with= =20 disasterous results.
 
I know what the actual heat range for the aircra= ft plugs=20 is in the high performance aircraft engine and the temperature margins th= at=20 are present.
 
But if I were to insert an automotive plug into = a bushing=20 screwed into the  cylinder head  of my air cooled  aircraf= t=20 engine I would have to merely  "hope"  that it was going to wor= k=20 based on a mixed set of anecdotal testimonials about their successful and= =20 unsuccessful use in aircraft engines reported by others.
 
That is all I am saying.
 
Hope is not really a method.
 
Regards,  George
 
 
 
 
 
 
 
 
 
From: Lancair Mailing List=20 [mailto:lml@lancaironline.net] On Behalf Of Chuck=20 Jensen
Sent: Friday, May 30, 2008 6:06 PM
To:=20 lml@lancaironline.net
Subject: [LML] Re: Electronic ignition sp= ark=20 plugs

George,
 
Your=20 postings are quite surprising, and a bit disappointing.  You point o= ut=20 that auto plugs are different that aviation plugs.  You point out th= at=20 you know the temperature of the aviation plugs during operations.  Y= ou=20 point out that auto plugs enjoys a heat sunk environment.  You point= out=20 that the aviation plug was designed for the aviation=20 environment.
 
All=20 of these are true, but unfortunately, you leave us to 'conclude' that tha= t=20 somehow means that the auto plug are unsatisfactory in the aviation=20 environment.  I don't like having to bridge such gaps in data.&= nbsp;=20 What  is it about auto plugs that are inadequate?  Peak temp=20 tolerance?  Temp rate of change?  Cylinder compression?  1= 00LL=20 gas?  Where do they fall short, other than they are 'different' from= =20 aviation plugs?
 
Personally, I run aviation plugs on both my mag and EI, but many= have=20 run auto plugs without problems.  Why, or how, were they successful = when=20 there are so many implied deficiencies with auto plugs?

Thanks, =
Chuck= =20 Jensen

 

-----Original Message-----
From: Lancair Mailing Lis= t=20 [mailto:lml@lancaironline.net]On Behalf Of George=20 Braly
Sent: Friday, May 30, 2008 9:45 AM
To:=20 lml@lancaironline.net
Subject: [LML] Re: Electronic ignition = spark=20 plugs

Colyn,
 
Other than curiosity - -   it is not= ,=20 frankly, important that I know what the number is supposed to be -= -=20
 
What is important is that nobody has a= clue=20 as to what the number is for the automotive spark plug mounted= in=20 the aircraft application.
 
Keep in mind that the automotive spark plug = enjoyes=20 being "heat sunk"  into a massive water cooled cylinder head that = is=20 held at constant temperature from a thermostat.
 
By=20 contrast, the aircraft spark plug is desgined for the much more variabl= e=20 environment of the air cooled cylinder head which can have temperatures= more=20 than twice as high as the automotive cylinder head.
 
There is a  casual acceptance of a subs= tantial=20 level of  "under-investigation"  that is associa= ted=20 with some of these often routinely accepted  recommendations to us= e=20 components that have not undergone   thoughtful testing at th= e=20 boundary conditions of  realistic operating=20 environments.  
 
Regards,  George
 
PS>  The answer to your question is = in some=20 of the APS class materials.  We made a power point slide that deta= iled=20 the aircraft spark plug ceramic temperature as a function of  A/F= =20 ratio.
 

From: Lancair Mailing List=20 [mailto:lml@lancaironline.net] On Behalf Of Colyn Case at=20 earthlink
Sent: Wednesday, May 28, 2008 9:37 PM
To:= =20 lml@lancaironline.net
Subject: [LML] Re: Electronic ignition = spark=20 plugs

George said
I can tell you the answer to that question wi= th=20 respect to an aviation spark plug.
 
okay, what's the answer? say, 50 dF LOP 32"= =20 TSIO-550 ....or whatever you actually=20 have.
 
 
--_000_C273A1B35F3C6748B52EE0CC2FCEE96C6DE070EC15gamimail1Gami_--