X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from fed1rmmtao106.cox.net ([68.230.241.40] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTP id 3991442 for flyrotary@lancaironline.net; Wed, 25 Nov 2009 20:31:07 -0500 Received-SPF: none receiver=logan.com; client-ip=68.230.241.40; envelope-from=alventures@cox.net Received: from fed1rmimpo03.cox.net ([70.169.32.75]) by fed1rmmtao106.cox.net (InterMail vM.8.00.01.00 201-2244-105-20090324) with ESMTP id <20091126013030.JVEX21192.fed1rmmtao106.cox.net@fed1rmimpo03.cox.net> for ; Wed, 25 Nov 2009 20:30:30 -0500 Received: from BigAl ([72.192.141.69]) by fed1rmimpo03.cox.net with bizsmtp id 9dWV1d00F1W2PoQ04dWVAc; Wed, 25 Nov 2009 20:30:30 -0500 X-VR-Score: 0.00 X-Authority-Analysis: v=1.0 c=1 a=Ia-xEzejAAAA:8 a=7g1VtSJxAAAA:8 a=sf9tu7tenx-7KYM1nJIA:9 a=gKpV_gOZpZ1BRUqrJ94A:7 a=Dq5_mXc35WPZHCWgbFFEpXMuj7gA:4 a=EzXvWhQp4_cA:10 a=YObQJjYt57Mu_p-KYnUA:9 a=jTUsbLiOtyYv_doh4K0A:7 a=9fmiaMPOWMFt3vsn91wI2gziNOEA:4 X-CM-Score: 0.00 From: "Al Gietzen" To: "'Rotary motors in aircraft'" Subject: RE: [FlyRotary] Ground isn't ground Date: Wed, 25 Nov 2009 17:30:50 -0800 Message-ID: <1A30E9F035B94E8BA0F894AC05DEC79F@BigAl> MIME-Version: 1.0 Content-Type: multipart/alternative; boundary="----=_NextPart_000_0022_01CA6DF5.084FC0E0" X-Priority: 3 (Normal) X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook, Build 10.0.6856 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 Thread-Index: AcprisUaeTwLtuP/RNuvdAp1wcpQpACqVWkg Importance: Normal In-Reply-To: This is a multi-part message in MIME format. ------=_NextPart_000_0022_01CA6DF5.084FC0E0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable I did a measurement today for the resistance from the starter flange at = the re-drive plate to the copper tube, which is my ground bus going from = engine compartment back to the batteries that are in the nose of the Velocity. = The ground strap from the engine is from the bottom right corner of the = front cover. So this is the measurement through the engine (20B), back to = front, and after the two connections =96 cover to strap, strap to bus. =20 The resistance measurement was really too small the get a good reading = on the Fluke; say less than a milliohm. Then measured the voltage drop = while engine cranking =96 about 10 milivolts. Clamp-on ammeter suggests about = 50-60 amps draw to the starter after first surge. The math says resistance is about 0.2 miliohms. So as least in my case; grounding in this manner is = not an issue. =20 So weak spark during cranking is some other reason; I=92m wondering if = it could be due to very short dwell time from EC2 at low rpm that Steve = Boese reported here some time back. Don=92t know if 3-rotor would have same = effect, but likely would. Tracy; maybe you could comment on whether that could = be a factor. Never had starting problem, just noted spark during cranking significantly weaker than test mode =96 hard to get it to jump =BC=94. =20 Al G. =20 =20 -----Original Message----- From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On Behalf Of Steve Brooks Sent: Sunday, November 22, 2009 7:44 AM To: Rotary motors in aircraft Subject: [FlyRotary] Ground isn't ground =20 The mystery of my intermittent spark is solved. Thank you to all of=20 those who made suggestions, as it helped get to the bottom of the issue. This morning I decided to repeat the test I made yesterday hooking the=20 starter to a separate spare battery that I had. =20 This time I removed both the large cables going to the starter and=20 engine block ground. That way, I didn't have to mess with a jumper=20 cable. I hooked up the battery, turned the master on and engaged the=20 starter. To my utter amazement the spark was intermittent again. I=20 thought thgat certainly I hadn't made a mistake yesterday an imagined=20 that the spark was good on a separate starting battery. After some=20 swearing, I thought about yesterdays test, and the only thing different=20 was the ground cable. So, I removed the ground cable from the=20 battery,and hooked up a jumper cable from the negative terminal of the=20 battery, and hooked it up to the reduction drive plate, as I had done=20 yesterday. Cranked the starter and had good spark. Did it twice, just = to make sure. =20 What the **** ! =20 So, I decided to connect the jumper cable to the ground cable end,=20 instead of clamping it the the reduction drive plate. Cranked the=20 starter, and had intermittent spark again. Somewhat amazed, but onto=20 something here. =20 I measured the cable (0 gauge multi-strand silicone) with the Fluke=20 meter, and it showed pretty much zero ohms. I measured from the spot on = the front engine housing where I had the ground bolted on to the=20 reduction plate, and measured about 3 tenths of an ohm. =20 Since my original installation, I always had the ground cabled bolted to = the front housing, with a bolt into one of the tapped holes where the=20 air conditioner mount was. It is a pretty large bolt, and I never=20 suspected that, considering all of the bolts that hold the engine=20 together, and the many bolts that hold the reduction drive plate, that=20 there would be any issue. Boy was I wrong. =20 I reconnected the cables to the main battery, instead of the spare=20 battery, and instead of bolting the negative cable back on, I used the=20 jumper cable to connect to the reduction plate again. Perfect spark=20 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! =20 My current ground cable isn't long enough to reach from the battery to=20 the mounting plate. I found the cable that I had left, and I have=20 plenty of spare cable, but I don't have any more of the lugs for the=20 ends, so I will have to order some. I am going to attach to ground=20 inder one of the mounting bolts for the starter.=20 =20 Regards and thanks for the help, =20 Steve Brooks =20 =20 =20 =20 -- Homepage: http://www.flyrotary.com/ Archive and UnSub: http://mail.lancaironline.net:81/lists/flyrotary/List.html ------=_NextPart_000_0022_01CA6DF5.084FC0E0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable

I did a = measurement today for the resistance from the starter flange at the re-drive plate to the = copper tube, which is my ground bus going from engine compartment back to the = batteries that are in the nose of the Velocity.  = The ground strap from the engine is from the bottom right corner of the front = cover.  So this is the measurement through the engine (20B), back to front, and = after the two connections – cover to strap, strap to bus.

 

The resistance measurement was really too small the get a good reading on the Fluke; = say less than a milliohm.  Then measured the voltage drop while engine = cranking – about 10 milivolts.  Clamp-on ammeter suggests about 50-60 amps = draw to the starter after first surge.  The math says resistance is about = 0.2 miliohms.  So as least in my case; grounding in this manner is not an = issue.

 

So weak spark = during cranking is some other reason; I’m wondering if it could be due to = very short dwell time from EC2 at low rpm that Steve Boese reported here some = time back. Don’t know if 3-rotor would have same effect, but likely would.  Tracy; maybe = you could comment on whether that could be a factor.  Never had starting = problem, just noted spark during cranking significantly weaker than test mode – = hard to get it to jump ¼”.

 

Al = G.

 

 

-----Original Message-----
From: Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] On = Behalf Of Steve Brooks
Sent: Sunday, November 22, 2009 7:44 AM
To: Rotary motors in aircraft
Subject: [FlyRotary] Ground isn't ground

 

The mystery of my intermittent spark is solved.  Thank you to all of =

those who made suggestions, as it helped get to the bottom of the = issue.

This morning I decided to repeat the test I made yesterday hooking the =

starter to a separate spare battery that I had.

 

This time I removed both the large cables going to the starter and =

engine block ground.  That way, I didn't have to mess with a jumper =

cable.  I hooked up the battery, turned the master on and engaged the =

starter.  To my utter amazement the spark was intermittent again.  I =

thought thgat certainly I hadn't made a mistake yesterday an imagined =

that the spark was good on a separate starting battery.  After some =

swearing, I thought about yesterdays test, and the only thing different =

was the ground cable.  So, I removed the ground cable from the =

battery,and hooked up a jumper cable from the negative terminal of the =

battery, and hooked it up to the reduction drive plate, as I had done =

yesterday.   Cranked the starter and had good spark.  Did it twice, just =

to make sure.

 

What the **** !

 

So, I decided to connect the jumper cable to the ground cable end, =

instead of clamping it the the reduction drive plate.  Cranked the =

starter, and had intermittent spark again.  Somewhat amazed, but onto =

something here.

 

I measured the cable (0 gauge multi-strand silicone) with the Fluke =

meter, and it showed pretty much zero ohms.  I measured from the spot on =

the front engine housing where I had the ground bolted on to the =

reduction plate, and measured about 3 tenths of an ohm.

 

Since my original installation, I always had the ground cabled bolted to =

the front housing, with a bolt into one of the tapped holes where the =

air conditioner mount was.  It is a pretty large bolt, and I never =

suspected that, considering all of the bolts that hold the engine =

together, and the many bolts that hold the reduction drive plate, that =

there would be any issue.  Boy was I wrong.

 

I reconnected the cables to the main battery, instead of the spare =

battery, and instead of bolting the negative cable back on, I used the =

jumper cable to connect to the reduction plate again.  Perfect spark =

!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!= !!

 

My current ground cable isn't long enough to reach from the battery to =

the mounting plate.  I found the cable that I had left, and I have =

plenty of spare cable, but I don't have any more of the lugs for the =

ends, so I will have to order some.  I am going to attach to ground =

inder one of the mounting bolts for the starter.

 

Regards and thanks for the help,

 

Steve Brooks

 

 

 

 

--

Homepage:  http://www.flyrotary.com/

Archive and UnSub:   http://mail.lancaironline.net:81/lists/flyrotary/List.html<= /p>

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