X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [24.25.9.101] (HELO ms-smtp-02-eri0.southeast.rr.com) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 931822 for flyrotary@lancaironline.net; Wed, 18 Jan 2006 16:20:35 -0500 Received-SPF: pass receiver=logan.com; client-ip=24.25.9.101; envelope-from=eanderson@carolina.rr.com Received: from edward2 (cpe-024-074-025-165.carolina.res.rr.com [24.74.25.165]) by ms-smtp-02-eri0.southeast.rr.com (8.13.4/8.13.4) with SMTP id k0ILJlo5008577 for ; Wed, 18 Jan 2006 16:19:49 -0500 (EST) Message-ID: <000e01c61c74$eea54370$2402a8c0@edward2> From: "Ed Anderson" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: LS1 Coil Failures Date: Wed, 18 Jan 2006 16:19:56 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_000B_01C61C4B.05749850" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.2180 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.2180 X-Virus-Scanned: Symantec AntiVirus Scan Engine This is a multi-part message in MIME format. ------=_NextPart_000_000B_01C61C4B.05749850 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Thanks for a second data point, Mark. I strongly suspect that you are correct, we simply are driving coils = designed for start/stop slow go automobiles rather than constant hour = after hour of 6000+ rpm operations. But, I suspect that excess heat is still the core of the problem whether = under cowl heat or internal heat due to electrical power use at high = rpms. Ed ----- Original Message -----=20 From: Mark R Steitle=20 To: Rotary motors in aircraft=20 Sent: Wednesday, January 18, 2006 11:27 AM Subject: [FlyRotary] Re: LS1 Coil Failures Ed,=20 I was thinking about this a while back and was astounded at how many = "firings" per second these coils are producing. Each rotor fires = once/revolution of the eccentric shaft. Cruising along at 6000rpm, = that's 600 sparks/second/coil. My 5.3L Chevy truck (with LS1 coils), = cruising down the highway at 1500 rpm, each coil fires once every other = revolution, or 750 times/minute, or 12.5 times/second. So, we're really = pushing these coils to the limit. I find it amazing that they don't = fail more often than this. By the way, in 126,000 miles, I have yet to = have a coil fail on my LS1. =20 =20 Mark S. =20 -------------------------------------------------------------------------= ----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] = On Behalf Of Ed Anderson Sent: Wednesday, January 18, 2006 9:09 AM To: Rotary motors in aircraft Subject: [FlyRotary] LS1 Coil Failures =20 Hummm, think I will hold off swapping my stock Mazda Coils for the = LS1s sitting on my work bench until we have a better handle on the coil = "problem". Have now flow for 300 + hours and over six years with the = stock coils with the only problem being the early failure of the leading = module because of a resistor opening in its base. =20 =20 The wattage of the resistor is apparently too low to carry the load of = the ignition continuously running at 6000+ rpm. Replaced the resistor = with a higher wattage one and no more problem. At least three people = have had this resistor fail using the stock coils - it may well be that = the auto folks don't design for their coils to be run at high continuous = rpms unlike the MSD type ignitions for racing.=20 =20 I wonder what the automobile circle are experiencing with their LS1 = coils - anyone know? =20 =20 Ed A ----- Original Message -----=20 From: al p wick=20 To: Rotary motors in aircraft=20 Sent: Wednesday, January 18, 2006 9:57 AM Subject: [FlyRotary] Re: Coil & Alt cooling, Buly's input shaft =20 I'm wondering if 180f under hood is really the main cause for coil = fail? Auto's shut off hot in desert, black steel hood, must see temps = way beyond anything we can throw at them. You can't get those puppies to = fail regardless of environment. Perhaps there are one or two other = significant causes. I'd be real quick to abandon that manufacturer. =20 -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru = 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html =20 On Tue, 17 Jan 2006 22:39:15 -0500 "Tracy Crook" = writes: During my preflight tests this morning I found the third failed = ignition coil in the last 150 hours so I finally got serious about = dropping the temps around my coils and alternator. =20 =20 I've been concerned about this since the under-cowl temps are as = high as 180 deg F (delta T through rads is 70 - 90 deg F). The attached = photo shows the solution (hopefully). The alternator plenum is made = from a Tupperware container pirated from the kitchen with a skirt made = from sheet silicone rubber. A 5/8" ID vinyl hose routes cool air from = the oil cooler plenum to it. ( 3/8" ID hose was tried first, not quite = good enough) This was tried prior to today's scrubbed flight and a temp = probe shows that air inlet temps to the alternator are only 3 - 5 = degrees above ambient. Nice. =20 I had recently added a cooling plenum around the coils (also made = of tupperware) and fed by a 3/8" ID hose but it was pretty leaky and = only dropped temps about 10 - 15 degrees. After replacing the coil = today I built a better fitting plenum and fed it with 5/8" ID hose. = This one is made of space-age cardboard and I'll build a more permanent = one from fiberglass if it works OK. Will test tomorrow if wx allows. =20 Input shaft =20 Buly, got your input shaft today and checked it out. The thrust = bearing rollers & races look a little stressed but the roller cage has = been completely trashed. I do not think the .005" out of flatness on = your bellhousing would explain this and the odd wear pattern on the = plate. The marks and discoloration (heat) on the bearing and shaft look = as if there is misalignment between the E-shaft and the gear drive. = When you built the plate & bellhousing adapter for the drive, how did = you verify concentricity? This is much harder to do than verifying the = parallelism of the bellhousing and plate but is absolutely vital. There = is no question that the drive would have soon failed if you had = continued to run it. Glad this showed up before flight. =20 Tracy (Happy to hear that Dave L. is safe! Good flying. ) =20 -al wick Artificial intelligence in cockpit, Cozy IV powered by stock Subaru = 2.5 N9032U 200+ hours on engine/airframe from Portland, Oregon Prop construct, Subaru install, Risk assessment, Glass panel design = info: http://www.maddyhome.com/canardpages/pages/alwick/index.html ------=_NextPart_000_000B_01C61C4B.05749850 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Thanks for a second data point, = Mark.
 
I strongly suspect that you are correct, we = simply are=20 driving coils designed for start/stop slow go automobiles rather than = constant=20 hour after hour of 6000+ rpm operations.
 
But, I suspect that excess heat is still = the core of=20 the problem whether under cowl heat or internal heat due to electrical = power use=20 at high rpms.
 
Ed
----- Original Message -----
From:=20 Mark R Steitle =
Sent: Wednesday, January 18, = 2006 11:27=20 AM
Subject: [FlyRotary] Re: LS1 = Coil=20 Failures

Ed,=20

I was = thinking about=20 this a while back and was astounded at how many =93firings=94 per = second these=20 coils are producing.  Each rotor fires once/revolution of the = eccentric=20 shaft.  Cruising along at 6000rpm, that=92s 600 = sparks/second/coil. =20 My 5.3L Chevy truck (with LS1 coils), cruising down the highway at = 1500 rpm,=20 each coil fires once every other revolution, or 750 times/minute, or = 12.5=20 times/second.  So, we=92re really pushing these coils to the = limit.  I=20 find it amazing that they don=92t fail more often than this.  By = the way,=20 in 126,000 miles, I have yet to have a coil fail on my LS1. =20

 

Mark=20 S.

 

From:=20 Rotary motors in aircraft = [mailto:flyrotary@lancaironline.net] On=20 Behalf Of Ed Anderson
Sent: Wednesday, January 18, = 2006 9:09=20 AM
To: = Rotary motors in aircraft
Subject: [FlyRotary] LS1 Coil=20 Failures

 

Hummm, = think I will=20 hold off swapping my stock Mazda Coils for the LS1s sitting on my work = bench=20 until we have a better handle on the coil "problem".  Have now = flow for=20 300 + hours and over six years with the stock coils with the only = problem=20 being the early failure of the leading module because of a resistor = opening in=20 its base. 

 

The = wattage of the=20 resistor is apparently too low to carry the load of the ignition = continuously=20 running at 6000+ rpm.  Replaced the resistor with a higher = wattage one=20 and no more problem.  At least three people have had this = resistor fail=20 using the stock coils - it may well be that the auto folks don't = design for=20 their coils to be run at high continuous rpms unlike the MSD type = ignitions=20 for racing. 

 

I wonder = what the=20 automobile circle are experiencing with their  LS1 coils - anyone = know?

 

 

Ed=20 A

----- = Original=20 Message -----

From: al p = wick=20

To: Rotary motors in = aircraft=20

Sent: = Wednesday,=20 January 18, 2006 9:57 AM

Subject: = [FlyRotary] Re:=20 Coil & Alt cooling, Buly's input=20 shaft

 

I'm = wondering if=20 180f under hood is really the main cause for coil fail? Auto's shut = off hot=20 in desert, black steel hood, must see temps way beyond anything we = can throw=20 at them. You can't get those puppies to fail regardless of = environment.=20 Perhaps there are one or two other significant causes. I'd be real = quick to=20 abandon that manufacturer.

 


-al=20 wick
Artificial intelligence in cockpit, Cozy IV powered by stock = Subaru=20 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop construct, Subaru = install,=20 Risk assessment, Glass panel design info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html<= /SPAN>

 

On = Tue, 17 Jan=20 2006 22:39:15 -0500 "Tracy Crook" <lors01@msn.com>=20 writes:

During my=20 preflight tests this morning I found the third failed = ignition coil=20 in the last 150 hours so I finally got serious about dropping the = temps=20 around my coils and alternator.  =20

 

I've = been=20 concerned about this since the under-cowl temps are as high = as 180=20 deg F (delta T through rads is 70 - 90 deg F).  The = attached=20 photo shows the solution (hopefully).  The alternator plenum = is made=20 from a Tupperware container pirated from the kitchen with a skirt = made=20 from sheet silicone rubber.  A 5/8" ID vinyl hose routes cool = air=20 from the oil cooler plenum to it.   ( 3/8" ID hose was = tried=20 first, not quite good enough)  This was tried prior to = today's=20 scrubbed flight and a temp probe shows that air inlet temps to the = alternator are only 3 - 5 degrees above ambient. =20 Nice.

 

I = had recently=20 added a cooling plenum around the coils (also made of tupperware) = and fed=20 by a 3/8" ID hose but it was pretty leaky and only dropped = temps=20 about 10 - 15 degrees.  After replacing the coil today I = built a=20 better fitting plenum and fed it with 5/8" ID hose.  This one = is made=20 of space-age cardboard and I'll build a more permanent one from = fiberglass=20 if it works OK.  Will test tomorrow if wx=20 allows.

 

Input=20 shaft

 

Buly, got your=20 input shaft today and checked it out.  The thrust bearing = rollers=20 & races look a little stressed but the roller cage has been = completely=20 trashed.  I do not think the .005" out of flatness on your=20 bellhousing would explain this and the odd wear pattern on the=20 plate.  The marks and discoloration (heat) on the bearing and = shaft=20 look as if there is misalignment between the E-shaft  and the = gear=20 drive.  When you built the plate & bellhousing adapter = for the=20 drive, how did you verify concentricity?  This is much harder = to do=20 than verifying the parallelism of the bellhousing and plate but is = absolutely vital.  There is no question that the drive would = have=20 soon failed if you had continued to run it.   Glad this = showed=20 up before flight.

 

Tracy  (Happy=20 to hear that Dave L. is safe!  Good=20 flying. )

 


-al=20 wick
Artificial intelligence in cockpit, Cozy IV powered by stock = Subaru=20 2.5
N9032U 200+ hours on engine/airframe from Portland, Oregon
Prop construct, Subaru = install,=20 Risk assessment, Glass panel design=20 = info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html

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