X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Sender: To: lml@lancaironline.net Date: Sat, 31 May 2008 09:59:35 -0400 Message-ID: X-Original-Return-Path: Received: from [66.64.141.200] (HELO lucky.dts.local) by logan.com (CommuniGate Pro SMTP 5.2.3) with ESMTP id 2947068 for lml@lancaironline.net; Sat, 31 May 2008 09:42:44 -0400 Received-SPF: none receiver=logan.com; client-ip=66.64.141.200; envelope-from=cjensen@dts9000.com Content-class: urn:content-classes:message MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----_=_NextPart_001_01C8C323.D96BF7E4" Subject: RE: [LML] Re: Electronic ignition spark plugs X-MimeOLE: Produced By Microsoft Exchange V6.5 X-Original-Date: Sat, 31 May 2008 09:40:11 -0400 X-Original-Message-ID: <8984A39879F2F5418251CBEEC9C689B3AFCDF3@lucky.dts.local> In-Reply-To: X-MS-Has-Attach: X-MS-TNEF-Correlator: Thread-Topic: [LML] Re: Electronic ignition spark plugs Thread-Index: AcjDIRnVF9Avv8YeQ7CBdH+cy9b4QgAAULbA From: "Chuck Jensen" X-Original-To: "Lancair Mailing List" This is a multi-part message in MIME format. ------_=_NextPart_001_01C8C323.D96BF7E4 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable George, =20 I appreciate what you are saying (and especially appreciate of the = engine-education that your company has done, particularly in the area of = LOP operations). 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 empirical evidence that auto plugs are not up to the task, = at least for most GA applications. You advise that you don't know what = temp that auto plugs run at and whether it is within their design range. = So, when we talk about 'anecdotal' information, it seems to me that the = reports linking engine damage and auto spark plugs is the true anecdotal = information. =20 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 that 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 agree that guilt by association doesn't work for crime or = mechanical failure. =20 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 opinion (not to be dismissed out of hand) that it is not a = good idea. With that 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 should not be used. =20 Chuck Jensen=20 =20 -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net]On Behalf Of = George Braly Sent: Saturday, May 31, 2008 9:22 AM To: lml@lancaironline.net Subject: [LML] Re: Electronic ignition spark plugs =20 =20 Chuck, =20 I'm sorry if my posting was disappointing. =20 But I tried to make sure it was factual and informative. It may not be = helpful - - for those that want to go ahead and hope that the = automtoive plugs will work in their application. =20 I am NOT asserting that the automotive splugs are, in fact, = unsatisfactory.=20 =20 What I AM asserting is that unless someone has meaesured the actual = temperature 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 engines. =20 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 unsuitable in at least some portions of the normal operating = envelope. =20 >> What is it about auto plugs that are inadequate? Peak temp = tolerance? Temp rate of change? Cylinder compression? 100LL gas? = Where do they fall short, ...<< =20 I don't know where they fall short in any or all of the areas about = which you inquire. But none of those are the one about which I am most = concerned. =20 The operating temperature of the spark plug ceramic under hot day high = power conditions across the full range of allowable combustion A/F = ratios is the first area of concern. If it doesn't qualify there - - = then nothing else matters. =20 And so far as I can tell - - nobody in the experimental aircraft world = knows the answer to that question. They may be just fine and run along = at a cool 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 method of assurance for safety critical items in aircraft. =20 =20 The fact that some people have run automotive plugs successfully in some = engines - - is a lot like saying that some people have successfully = used car gas in their aircraft engine. =20 Unless you know that they have used that gasoline under the worst case = conditions that YOU will ever encounter with your engine and that your = engine is "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 be the same or equivelent gas bought from the = earlier supplier for the earlier test - - - then you really are just = following the "hope as a method" concept for assuring that your use of = similar car gasoline would work in your particular application. =20 I can go out and run a 350 Hp Navajo Chieftan turbocharged engine all = day at 210 Hp and do it on premium car gas. =20 =20 But if I try to run it at 230 Hp on a hot day with hot cylinders in a = single engine climb - - it is going to detonate. =20 Or if I try to run it at 270 Hp on any day, it is going to detonate. =20 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 "hope as a method" concept and try the same thing - - with = disasterous results. =20 I know what the actual heat range for the aircraft plugs is in the high = performance aircraft engine and the temperature margins that are = present. =20 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 testimonials about their successful and unsuccessful use in = aircraft engines reported by others.=20 =20 That is all I am saying. =20 Hope is not really a method. =20 Regards, George =20 =20 =20 =20 =20 =20 =20 =20 =20 _____ =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Chuck Jensen Sent: Friday, May 30, 2008 6:06 PM To: lml@lancaironline.net Subject: [LML] Re: Electronic ignition spark plugs George, =20 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 out that auto plugs enjoys a heat sunk environment. You point = out that the aviation plug was designed for the aviation environment. =20 All of these are true, but unfortunately, you leave us to 'conclude' = that that somehow means that the auto plug are unsatisfactory in the = aviation environment. I don't like having to bridge such gaps in data. = What is it about auto plugs that are inadequate? Peak temp tolerance? = Temp rate of change? Cylinder compression? 100LL gas? Where do they = fall short, other than they are 'different' from aviation plugs? =20 Personally, I run aviation plugs on both my mag and EI, but many have = run auto plugs without problems. Why, or how, were they successful when = there are so many implied deficiencies with auto plugs? Thanks,=20 Chuck Jensen=20 =20 -----Original Message----- From: Lancair Mailing List [mailto:lml@lancaironline.net]On Behalf Of = George Braly Sent: Friday, May 30, 2008 9:45 AM To: lml@lancaironline.net Subject: [LML] Re: Electronic ignition spark plugs Colyn, =20 Other than curiosity - - it is not, frankly, important that I know = what the number is supposed to be - -=20 =20 What is important is that nobody has a clue as to what the number is for = the automotive spark plug mounted in the aircraft application. =20 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. =20 By contrast, the aircraft spark plug is desgined for the much more = variable environment of the air cooled cylinder head which can have = temperatures more than twice as high as the automotive cylinder head. =20 There is a casual acceptance of a substantial level of = "under-investigation" that is associated with some of these often = routinely accepted recommendations to use components that have not = undergone thoughtful testing at the boundary conditions of realistic = operating environments. =20 =20 Regards, George=20 =20 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 temperature as a function of A/F ratio. =20 _____ =20 From: Lancair Mailing List [mailto:lml@lancaironline.net] On Behalf Of = Colyn 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 = spark plug. =20 okay, what's the answer? say, 50 dF LOP 32" TSIO-550 ....or whatever you = actually have. =20 =20 ------_=_NextPart_001_01C8C323.D96BF7E4 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
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 run=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 = within=20 their design range.  So, when we talk about 'anecdotal' = information, it=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 simple=20 bad-luck with failure of a mechanical component at the same time that an = auto=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 that=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 = that=20 auto plugs, when used in similar applications to those already = proven,=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 = them 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 = spark=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 want=20 to go ahead and hope that the automtoive plugs will work in their=20 application.
 
I am NOT asserting that the automotive splugs = are, 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 = 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 = engines=20 - - then there is hard evidence that the heat range of the plugs is = marginal=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, = ...<<
 
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 = ceramic under=20 hot day high power conditions across the full range of allowable = combustion=20 A/F ratios is the first area of concern.  If it doesn't qualify = there - -=20 then nothing else matters.
 
And so far as I can tell - - nobody in the = experimental=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 hoping=20 "yes" but nobody knows and nobody has the data.  I assume that = you agree=20 that hope should not be a method of assurance for safety critical = items=20 in aircraft.
 
 
The fact that some people have run automotive = plugs=20 successfully in some engines - -  is a lot like saying that some = people=20 have successfully used car gas in their aircraft = engine.
 
Unless you know that they have used that = gasoline under=20 the worst case conditions that YOU will ever encounter with your = engine and=20 that your engine is "less critical or the same" as the engine that = someone=20 else used - - and that when you buy your automotive gas from your = local dealer=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 = following=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 = Chieftan=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 = with 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 is going=20 to detonate.
 
But if I just told people that " I have run a = TIO-540J2Bd=20 engine on car gas" - - -  then it is likely that someone else = will decide=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 = aircraft plugs=20 is in the high performance aircraft engine and the temperature margins = that=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  = aircraft=20 engine I would have to merely  "hope"  that it was going to = work=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 = spark=20 plugs

George,
 
Your=20 postings are quite surprising, and a bit disappointing.  You = point out=20 that auto plugs are different that aviation plugs.  You point out = that=20 you know the temperature of the aviation plugs during = operations.  You=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 = that=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. =20 What  is it about auto plugs that are inadequate?  Peak temp = tolerance?  Temp rate of change?  Cylinder = compression?  100LL=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 = List=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 = variable=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 = substantial=20 level of  "under-investigation"  that is = associated=20 with some of these often routinely accepted  recommendations to = use=20 components that have not undergone   thoughtful testing at = the=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 = detailed=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 = with=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.
 
 
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