X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from web83901.mail.sp1.yahoo.com ([69.147.92.97] verified) by logan.com (CommuniGate Pro SMTP 5.3.9) with SMTP id 4487516 for flyrotary@lancaironline.net; Thu, 30 Sep 2010 11:37:58 -0400 Received-SPF: none receiver=logan.com; client-ip=69.147.92.97; envelope-from=keltro@att.net Received: (qmail 68647 invoked by uid 60001); 30 Sep 2010 15:30:29 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=att.net; s=s1024; t=1285860629; bh=oaB49WvycHO2xnrp5Il/PWagh+EuILSfSehtd8Z+vCk=; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=sAmv0/7qvKK8/rC3zpPMZIGH9d5XmkT8mqO43SdPLapY9MZnSPMWALAhK1khdoggUgMv5Km6+UZGc7kgEbPMvSvDCBmnShsCsQFXtHBJrehX5cosE8aNkdkVT6fmu+JlDKB1+Q9+GXI7yyx3b2tHj1bguoRT+OQ3neobXctO9RM= DomainKey-Signature:a=rsa-sha1; q=dns; c=nofws; s=s1024; d=att.net; h=Message-ID:X-YMail-OSG:Received:X-Mailer:References:Date:From:Subject:To:In-Reply-To:MIME-Version:Content-Type; b=fwtbY78WAFqUnwCT4vFK3I1QSCbuUuXyqSsomyQ3TTvhspMWJdkLMJa9W45XjYLqSRUrjXwlMAhXw3pS8qlOk43qfxCgl8+aMiCigaEfJW/GB7lDC4tw0OfwU1kh5q9g9dNnjKqEUftxEeBt1ku4G07XywZAAxY6NTYZIuhOfjE=; Message-ID: <44907.67155.qm@web83901.mail.sp1.yahoo.com> X-YMail-OSG: PihE2wUVM1lhf_oYbvCx06mp9nb2jSJTk0b2qOJmcJOHwfn 1kUn3S0IEsh3VUsPMRXtjXcZscT8hTbsTYcrQyq0jBc02XxNGgsKrV5X..Wk GlxaPL9tVB_ABvoa0MVYERIgOjH5juOA.RhQhxSRaWK.xwyJ7iOV7S.bjR5R X1ZNPSo1NLQDtYTOqLTvHGLHJf1_kJcWz.GOTSUwKs8ZDgrpaOzQl2ulGZMm wX3b5QAhTj.mI7zQvUnA9ZzJbZ09fpfz97rgvRCNFtHeacp42eBROdyF._f3 Yvi6MJnlbtT17kCjGOKBYspezeUwjhA._GcQN8upRCDPtV5Cti9SdII6G5bE 4 Received: from [208.114.43.242] by web83901.mail.sp1.yahoo.com via HTTP; Thu, 30 Sep 2010 08:30:28 PDT X-Mailer: YahooMailRC/497 YahooMailWebService/0.8.105.279950 References: Date: Thu, 30 Sep 2010 08:30:28 -0700 (PDT) From: Kelly Troyer Subject: New SAG Theory Discussions of SAG To: Rotary motors in aircraft In-Reply-To: MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="0-960698834-1285860628=:67155" --0-960698834-1285860628=:67155 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable Steve,=0A=A0=A0 Realizing that=A0any improvement in plug life before "SAG" = starts=A0have yet to =0Abe proved=0Acan you give us the plug make and part = # from "Racing Beat"=A0and what heat range =0A# is =0A=0Aclaimed (Also real= izing heat range #'s are not the same between plug =0Amanufacturers)...=0AK= elly Troyer=0A"Dyke Delta"_13B ROTARY Engine=0A"RWS"_RD1C/EC2/EM2=0A"Mistra= l"_Backplate/Oil Manifold =0A=0A=0A=0A=0A________________________________= =0AFrom: Steven W. Boese =0ATo: Rotary motors in aircraft = =0ASent: Thu, September 30, 2010 10:14:06 AM= =0ASubject: [FlyRotary] Re: New SAG Theory Discussions of SAG=0A=0A=0AEd,= =0A=A0=0AYou take good notes.=0A=A0=0AJust a couple of clarifications:=A0 T= he decrease in the thermal conductivity of =0Athe copper core may be the re= sult of thermal cycling=A0causing development of =0Aporosity within the cop= per.=A0 This=A0is independent of the corrosion going on =0Abetween the Mn a= lloy electrode sheath and the insulator.=A0 So there are two =0Aessentially= independent mechanisms contributing to the heat range change of the =0Aspa= rk plug with age.=A0 =0A=0A=A0=0AThe development of the porosity within the= copper is not particularly affected =0Aby the type of fuel whereas the cor= rosion between the Mn alloy sheath and the =0Ainsulator=A0is accelerated by= the use of 100LL.=0A=A0=0AThe cure is still to install new spark plugs.=A0= =0A=A0=0AI have colder spark plugs from Racing Beat that are recommended f= or prolonged =0Ause=A0in high RPM high power applications.=A0 At best, the = colder plugs will merely =0Adelay the onset of SAG but=A0won't prevent it f= rom happening eventually.=A0 It will =0Abe some time before the results of = using those plugs will be known.=0A=A0=0ASteve Boese=0A=A0=0A=A0=A0 =0A=A0= =0A=0A________________________________=0AFrom: Rotary motors in aircraft [f= lyrotary@lancaironline.net] On Behalf Of Ed =0AAnderson [eanderson@carolina= .rr.com]=0ASent: Thursday, September 30, 2010 8:46 AM=0ATo: Rotary motors i= n aircraft=0ASubject: [FlyRotary] New SAG Theory Discussions of SAG=0A=0A= =0AIn a nut shell, Steve's excellent data gathering (how many of use have a= ccess to =0Aa scanning electron microscope or spectrum analyzer {:>)) and a= nalysis indicates =0Aa possible alternative reason for SAG other than fouli= ng.=A0=0A=A0=0A=A0It basically boils down to a theory of pre-ignition based= on the deteorating =0Aheat removal capacity of the plug.=A0 =0A=0A=A0=0ATh= ere is a copper core (the photos showing the two cores) in the center of th= e =0Aceramic cone which is responsible for conducting 90% of the heat away = from the =0Acenter electrode.=A0 Based on Steve's' electron microscope view= ing of two cores =0A(one new and one having been used in a 100LL environmen= t), it appears that the =0Aplug using leaded gasoline has corrosion occurri= ng on the boundary between this =0Acopper core and the surrounding (hot) el= ements.=A0 This layer of corrosion hinders =0Aheat removal from the plug le= ading to parts of the plug becoming hot enough to =0Atrigger pre-ignition.= =0A=A0=0AThis SAG tends to happened at high power settings and reducing pow= er tends to =0Amake it go away (for a while).=A0 Steve's theory is that the= plug encounters max =0Aheat and temperature at high power settings and tha= t reducing the power permits =0Athe plug to cool off enough for the pre-ign= ition to go away (for a while).=0A=A0=0ASo we now have two theories - one i= s the fouled plug and one of the overheated =0Aplug causing SAG.=A0 Preigni= tion generally leads to detonation which does not =0Aappear to be happening= (at least no one is finding the typical detonation damage =0Ato the rotary= engine).=A0 A possible reason is the quenching effect of the less =0Athan = optimum shape of the rotary combustion space may tend to delay or prevent = =0Athe onset of detonation damage that one would expect from continuous pre= ignition =0Acaused by a too hot plug.=0A=A0=0AI believe Steve intends to se= e if he can find some colder plugs (the ones that =0Aconduct heat better) a= nd see if that extends the time between SAG.=A0 Currently I =0Afind that ro= ughly 25-30 hours is about the max I can get using 100LL before SAG =0Asets= in, whereas Tracy and others have well over 150 hours using unleaded =0AMo= gas.=A0 So if the colder plugs extend the time before SAG, I would say that= =0Apretty much would suggest Steve's theory is correct - if Not, then perh= aps the =0Afouled Plug theory still has merit or it could be some other phe= nomena =0Ahappening.=0A=A0=0ASteve, my apologies if I did not present your = case as well as you could=0A=A0=0AEd=0A=A0=0AEdward L. Anderson=0AAnderson = Electronic Enterprises LLC=0A305 Reefton Road=0AWeddington, NC 28104=0Ahttp= ://www.andersonee.com=0Ahttp://www.eicommander.com=0A=0A=A0=0A.=0A=A0=0A=A0= =0A=0A=0AFrom: Bill Bradburry =0ASent: Thursday, September 30, 2010 9:59 AM= =0ATo: Rotary motors in aircraft =0ASubject: [FlyRotary] Discussions of SAG= =0A=0AI understand that there was a presentation on SAG at the meeting.=A0 = Can someone =0Ago over the alternative theory with the ones of us that were= not in attendance?=A0 =0AIt looked like someone had a scanning electron mi= croscope photo that they were =0Ashowing!=A0 Wow!=A0 Are we getting sophist= icated or what!!=A0 Was this an explanation =0Aof the cause, or ideas for p= revention, both??=0A=A0=0ABill B --0-960698834-1285860628=:67155 Content-Type: text/html; charset=iso-8859-1 Content-Transfer-Encoding: quoted-printable
=0A
Steve,
=0A
   Realizing that&nbs= p;any improvement in plug life before "SAG" starts have yet to be prov= ed
can you give us the plug make and part # from "Racing Beat" and = what heat range # is
=0A
claimed (Also realizing heat range #'s a= re not the same between plug manufacturers)...
=0A
 
Kel= ly Troyer
"Dyke Delta"_13B ROTARY Engine
"RWS"_RD1C/EC2/EM2
"Mistr= al"_Backplate/Oil Manifold =0A

=0A

=0A
=0A
=0A= From: Steven W. Boese <SBoese@uwyo.edu>
To: Rotary motors in aircraft <flyrota= ry@lancaironline.net>
Sent: Thu, September 30, 2010 10:14:06 AM
Subject: [FlyRotary] Re: New SAG Theory Discussions of S= AG

=0A= =0A=0A=0A=0A=0A=0A
=0A
Ed,
=0A
 
=0A
You take= good notes.
=0A
 =
=0A
Just a couple of clarifications:=   The decrease in the thermal conductivity of the copper core may be t= he result of thermal cycling causing development of porosity within th= e copper.  This is independent of the corrosion going on between = the Mn alloy electrode sheath and the insulator.  So there are two ess= entially independent mechanisms contributing to the heat range change of th= e spark plug with age. 
=0A
 
=0A
The development= of the porosity within the copper is not particularly affected by the type= of fuel whereas the corrosion between the Mn alloy sheath and the insulato= r is accelerated by the use of 100LL.
=0A
 
=0A
= The cure is still to install new spark plugs. 
=0A
<= /FONT> 
=0A
I have colder spark plugs from Racing Beat that are recommended for = prolonged use in high RPM high power applications.  At best, the = colder plugs will merely delay the onset of SAG but won't prevent it f= rom happening eventually.  It will be some time before the results of = using those plugs will be known.
=0A
 
=0A
Steve= Boese
=0A
 
= =0A
  
=0A
 
=0A<= DIV style=3D"DIRECTION: ltr" id=3DdivRpF17061>=0A
=0AFrom: Rotary motors in aircr= aft [flyrotary@lancaironline.net] On Behalf Of Ed Anderson [eanderson@carol= ina.rr.com]
Sent: Thursday, September 30, 2010 8:46 AM
To:<= /B> Rotary motors in aircraft
Subject: [FlyRotary] New SAG Theory= Discussions of SAG

=0A
=0A
=0A
In a nut shell, Steve's excellent data gathering (how many of= use have access to a scanning electron microscope or spectrum analyzer {:&= gt;)) and analysis indicates a possible alternative reason for SAG other th= an fouling. 
=0A
 =0A
 It basically boils down to a theory of pr= e-ignition based on the deteorating heat removal capacity of the plug. = ;
=0A
 
=0A
There is a copper core (the photos showing the two cores) in t= he center of the ceramic cone which is responsible for conducting 90% of th= e heat away from the center electrode.  Based on Steve's' electron mic= roscope viewing of two cores (one new and one having been used in a 100LL e= nvironment), it appears that the plug using leaded gasoline has corrosion o= ccurring on the boundary between this copper core and the surrounding (hot)= elements.  This layer of corrosion hinders heat removal from the plug= leading to parts of the plug becoming hot enough to trigger pre-ignition.<= /FONT>
=0A
 
=0A
This SAG tends to happened at high power settings and reducing po= wer tends to make it go away (for a while).  Steve's theory is that th= e plug encounters max heat and temperature at high power settings and that = reducing the power permits the plug to cool off enough for the pre-ignition= to go away (for a while).
=0A
&n= bsp;
=0A
So we now have two theories - one is t= he fouled plug and one of the overheated plug causing SAG.  Preignitio= n generally leads to detonation which does not appear to be happening (at l= east no one is finding the typical detonation damage to the rotary engine).=   A possible reason is the quenching effect of the less than optimum s= hape of the rotary combustion space may tend to delay or prevent the onset = of detonation damage that one would expect from continuous preignition caus= ed by a too hot plug.
=0A
 <= /DIV>=0A
I believe Steve intends to see if he can fi= nd some colder plugs (the ones that conduct heat better) and see if that ex= tends the time between SAG.  Currently I find that roughly 25-30 hours= is about the max I can get using 100LL before SAG sets in, whereas Tracy a= nd others have well over 150 hours using unleaded Mogas.  So if the co= lder plugs extend the time before SAG, I would say that pretty much would s= uggest Steve's theory is correct - if Not, then perhaps the fouled Plug the= ory still has merit or it could be some other phenomena happening.=0A
 
=0A
Steve, my apologies if I did not present your case as well as you could
=0A
 
=0A
Ed
=0A
 
=0AEdward L. Anderson
Anderson Electronic Enterprises= LLC
305 Reefton Road
Weddington, NC 28104
http://www.andersonee.c= om
http://www.eicommander.com
=0A
 
=0A
.
=0A
 
=0A
 =0A
=0A

=0A
=0A=0ASent: Thursday, September 30, 2010 9:59 AM
=0A=0A
Subject: [Fly= Rotary] Discussions of SAG
=0A

=0A
=0A

I unders= tand that there was a presentation on SAG at the meeting.  Can someone= go over the alternative theory with the ones of us that were not in attend= ance?  It looked like someone had a scanning electron microscope photo= that they were showing!  Wow!  Are we getting sophisticated or w= hat!!  Was this an explanation of the cause, or ideas for prevention, = both??

=0A

 

=0A

Bill B

= --0-960698834-1285860628=:67155--