X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from [65.54.250.87] (HELO hotmail.com) by logan.com (CommuniGate Pro SMTP 5.0.6) with ESMTP id 931701 for flyrotary@lancaironline.net; Wed, 18 Jan 2006 14:42:58 -0500 Received-SPF: pass receiver=logan.com; client-ip=65.54.250.87; envelope-from=lors01@msn.com Received: from mail pickup service by hotmail.com with Microsoft SMTPSVC; Wed, 18 Jan 2006 11:42:13 -0800 Message-ID: Received: from 4.171.174.88 by BAY115-DAV15.phx.gbl with DAV; Wed, 18 Jan 2006 19:42:13 +0000 X-Originating-IP: [4.171.174.88] X-Originating-Email: [lors01@msn.com] X-Sender: lors01@msn.com From: "Tracy Crook" To: "Rotary motors in aircraft" References: Subject: Re: [FlyRotary] Re: Coil & Alt cooling, Buly's input shaft Date: Wed, 18 Jan 2006 14:42:08 -0500 MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_00F2_01C61C3D.5B8B33B0" X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: MSN 9 X-MimeOLE: Produced By MSN MimeOLE V9.10.0011.1703 Seal-Send-Time: Wed, 18 Jan 2006 14:42:08 -0500 X-OriginalArrivalTime: 18 Jan 2006 19:42:13.0387 (UTC) FILETIME=[4786E5B0:01C61C67] This is a multi-part message in MIME format. ------=_NextPart_000_00F2_01C61C3D.5B8B33B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable You are probably right about the post shutdown temps on cars in some = conditions but passive (un powered) heat exposure is a very different = thing than operating heat exposure. Keep in mind these are coil/igniter = modules with electronics in the same package, not a separate module as = in all Subarus (that I know of). The widely accepted semiconductor life = vs temperature factor is that life is cut in half for every 10 deg C = increase in temperature so it is good practice to keep them cool anyway. = =20 Having said that, the igniters I use may in fact have a problem under = the conditions I run them. The LS1 Corvette igniters (made by Nippon = Denso) have proven themselves reliable in aircraft service (Bill Eslick = has quite a few hours using them) but I think my under cowl temps are = significantly higher. This is partially by design (long cooling = discussion) and partially due to the Renesis characteristics. Another = factor is that I am using the LS1 truck engine version of the coils = which is supposed to be electrically equivalent to the Corvette part but = this may not be completely true. They are made by a different company = (Hitachi I think). I have plans to do some more testing to verify their = suitability. I was out of the truck parts so I replaced the dead coil = with a Corvette part.=20 In my preliminary tests, It does not look like they were overstressed by = this but the coil spark rate on the rotary (at 6000 rpm) is the same as = if the LS1 V8 were turning 12,000 rpm. Tracy (back from test flight after repair : ) ----- Original Message -----=20 From: al p wick=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. -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 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 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. 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. Input shaft 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. Tracy (Happy to hear that Dave L. is safe! Good flying. ) -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_00F2_01C61C3D.5B8B33B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
You are probably right about the post shutdown temps on cars in = some=20 conditions but passive (un powered) heat exposure is a very different = thing than=20 operating heat exposure.  Keep in mind these are coil/igniter = modules with=20 electronics in the same package, not a separate module as in all Subarus = (that I=20 know of).  The widely accepted semiconductor life vs temperature = factor is=20 that life is cut in half for every 10 deg C increase in temperature so = it is=20 good practice to keep them cool anyway. 
 
Having said that, the igniters I use may in fact have a = problem under=20 the conditions I run them.  The LS1 Corvette igniters (made by = Nippon=20 Denso) have proven themselves reliable in aircraft service (Bill Eslick = has=20 quite a few hours using them) but I think my under cowl temps = are=20 significantly higher.  This is partially by design (long cooling=20 discussion) and partially due to the Renesis=20 characteristics.   Another factor is that I am using = the LS1=20 truck engine version of the coils which is supposed to be electrically=20 equivalent to the Corvette part but this may not be completely = true.  They=20 are made by a different company (Hitachi I think).  I have plans to = do some=20 more testing to verify their suitability.  I was out of the = truck=20 parts so I replaced the dead coil with a Corvette part. 
 
In my preliminary tests, It does not look like they were = overstressed by=20 this but the coil spark rate on the rotary (at 6000 rpm) is the = same=20 as if the LS1 V8 were turning 12,000 rpm.
 
Tracy (back from test flight after repair : )
----- Original Message -----
From: al p wick

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

-al wick
Artificial intelligence in cockpit, Cozy IV = powered by=20 stock Subaru 2.5
N9032U 200+ hours on engine/airframe from = Portland,=20 Oregon
Prop construct, Subaru install, Risk assessment, Glass panel = design=20 info:
htt= p://www.maddyhome.com/canardpages/pages/alwick/index.html
 
On Tue, 17 Jan 2006 22:39:15 -0500 "Tracy Crook" <lors01@msn.com> writes:
During my preflight tests this morning I found the third = failed=20 ignition coil in the last 150 hours so I finally got serious about = dropping=20 the temps around my coils and alternator.  
 
I've been concerned about this since the under-cowl temps = are as=20 high as 180 deg F (delta T through rads is 70 - 90 deg = F).  The=20 attached photo shows the solution (hopefully).  The alternator = plenum=20 is made from a Tupperware container pirated from the kitchen with a = skirt=20 made 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=20 alternator are only 3 - 5 degrees above ambient.  Nice.
 
I had recently added a cooling plenum around the coils (also = made of=20 tupperware) and fed by a 3/8" ID hose but it was pretty leaky = and only=20 dropped temps about 10 - 15 degrees.  After replacing the coil = today I=20 built a better fitting plenum and fed it with 5/8" ID hose.  = This one=20 is made of space-age cardboard and I'll build a more permanent one = from=20 fiberglass if it works OK.  Will test tomorrow if wx = allows.
 
Input shaft
 
Buly, got your input shaft today and checked it out.  The = thrust=20 bearing rollers & races look a little stressed but the roller = cage has=20 been completely trashed.  I do not think the .005" out of = flatness on=20 your 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=20 absolutely vital.  There is no question that the drive would = have soon=20 failed if you had continued to run it.   Glad this showed = up=20 before flight.
 
Tracy  (Happy to hear that Dave L. is safe!  Good=20 flying. )
 

-al wick
Artificial = intelligence in=20 cockpit, Cozy IV powered by stock Subaru 2.5
N9032U 200+ hours on=20 engine/airframe from Portland, Oregon
Prop construct, Subaru = install, Risk=20 assessment, Glass panel design=20 = info:
http://www.maddyhome.com/canardpages/pages/alwick/index.html
= ------=_NextPart_000_00F2_01C61C3D.5B8B33B0--