X-Virus-Scanned: clean according to Sophos on Logan.com Return-Path: Received: from mail-ew0-f212.google.com ([209.85.219.212] verified) by logan.com (CommuniGate Pro SMTP 5.3c3) with ESMTP id 3990972 for flyrotary@lancaironline.net; Wed, 25 Nov 2009 13:14:53 -0500 Received-SPF: pass receiver=logan.com; client-ip=209.85.219.212; envelope-from=cozy4pilot@gmail.com Received: by ewy4 with SMTP id 4so4774733ewy.27 for ; Wed, 25 Nov 2009 10:14:17 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:mime-version:received:in-reply-to:references :date:message-id:subject:from:to:content-type; bh=8kzk6ID6UXEtcnTnv/hCP4TgT6BviFuM9wq9EqDxbcQ=; b=gxIr+ycqucIiJRR084e39i3TgEAulAUcD81Tr9S2l3Qi2PA9JKQPYvcs/wb/8xigGN CNiaUaZeSG5/FPSj5GKLum+Wz7KueRsQ2IWEldPbdPXKAEhXfF6+M/zKBDAwEsa6tVik o3Jh4eu/GiqpJ6aoXqJEFTE5PDTXYPSZ7a+DU= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=pFIkkfsHt/zznNQpE1mp2tdODpIBkjuH6RI3HHeaxDzcBX1/6ILlS/EoPK9zPHwxIU LRjKkhH/i4O5zIsZu6a9nH/OH5Cj35W+3/9mv81lzEwAtg1wEpubfyI/z8lzkASsyYjw j9tZx5Z3pYxEA+6SzN52d2sfwOfiqxoFQF/VU= MIME-Version: 1.0 Received: by 10.216.89.5 with SMTP id b5mr301838wef.143.1259172856824; Wed, 25 Nov 2009 10:14:16 -0800 (PST) In-Reply-To: References: Date: Wed, 25 Nov 2009 13:14:16 -0500 Message-ID: <7a025aa00911251014x22220809s82004fcf62039347@mail.gmail.com> Subject: Re: [FlyRotary] Re: No start From: Stephen Brooks To: Rotary motors in aircraft Content-Type: multipart/alternative; boundary=0016e6d7eea0d7843604793606d7 --0016e6d7eea0d7843604793606d7 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Finn, No, the shielded cable for the CAS is grounded on the EC-2 end only. Steve On Wed, Nov 25, 2009 at 10:44 AM, Finn Lassen wrot= e: > Does the CAS wiring have a shield grounded at both ends? > > Realize that when your main ground path to the starter was bad the curren= t > would find alternative paths. If on of those paths were CAS wiring it wou= ld > introduce a voltage drop in that wiring, just like inserting the 1.5 volt > battery... > > Finn > > Steve Brooks wrote: > >> Jeff, >> In my case, which is a pusher, my aft battery sits just inside the >> firewall on top of the wing spar. I have #10 wires that connect from the >> batery terminals to feed the power and fround buss for the fuel puels, >> coils, fuel injectors, EC-2, etc. I have two 1/0 AWG cables that also >> connect to the battery terminals. The positive runs back tot he starter,= and >> is about 6 feet long. The negative did run to one of the tapped holes fo= r >> the A/C compressor on the front engine housing. The ground is about 4 ft >> long currently. I am going to remove that cable and run the ground from = the >> battery to one of the starter mounting bolts, which will also make it ab= out >> 6 ft long. >> >> I also find it hard to believe that given all of the bolts in the mounti= ng >> plate, and the torsion bolts through the engine, that it wouldn't be a >> really good conductor, but I would apparently be mistaken. I am not exac= tly >> clear on how it interferrs with the CAS signal, but it does. My ground w= as >> mounted just below the CAS about 8 inches, so perhaps that has something= to >> do with it. It works fine there though for several years, before I start= ed >> having difficulty starting the engine. >> >> >> Regards, >> Steve Brooks >> Cozy MKIV >> Turbo rotary >> >> Jeff Whaley wrote: >> >>> >>> Good point on the anodizing Tracy; also a .005=94 layer of silicone isn= =92t >>> conductive either, even with bare aluminum =96 conduction is made throu= gh the >>> bolts and not the entire mating surface of the plate. The math checks o= ut >>> too. I=92m still curious about their specific setups though; I can see = how a >>> stack of aluminum/iron/aluminum, etc with a layer of hylomar in between= each >>> stack might not be the best conductor =96 the sub-mount plate has to he= lp. >>> >>> In my setup the battery is behind the cabin for weight and balance >>> considerations. Ground is made to a steel tube frame with about 1 foot = of #1 >>> welding cable; Positive runs through Master relay under the floor to >>> firewall with about 6 feet of same #1 welding cable, then another 2.5 f= eet >>> to starter. The engine ground is via stainless braid from front iron to >>> engine mount hardware at the firewall/airframe. So if the starter curre= nt >>> path is from post to post on the battery, then in my case it has to be = close >>> to 16 feet! I=92ve never had any starting problems, but it would be >>> interesting to see if an extra ground strap from starter bracket back t= o the >>> airframe makes the starter spin faster or engine fire sooner =85 will t= est >>> that and post results. >>> >>> Jeff >>> >>> *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] >>> *On Behalf Of *Tracy Crook >>> *Sent:* Tuesday, November 24, 2009 9:43 AM >>> *To:* Rotary motors in aircraft >>> *Subject:* [FlyRotary] Re: No start >>> >>> I doubt anodizing is a factor. Keep in mind that the starter we use is = a >>> light duty one but its rating is 1.2 KW. With a typical cranking voltag= e of >>> 10 volts, that's 120 amps. With that kind of current, the only logical >>> routing of the ground cable is as directly to the load as possible. >>> >>> Do the math. At that current level, it only takes about .008 ohms to dr= op >>> your working voltage a full 1 volt. That's 10% of your cranking power l= ost. >>> Rotaries are especially sensitive to cranking speed because they lose m= ore >>> compression than piston engines at low speed. Low compression makes sta= rting >>> more difficult. Losses in this circuit must be minimized for many reaso= ns. >>> Also note that the ground connection point that many have said they are >>> using goes very near the crank sensor and its wiring. This proximity ma= kes >>> inductive coupling into the CAS circuit more likely. >>> >>> Add all these factors up and it is not surprising that many builders ha= ve >>> starting problems. >>> >>> Tracy >>> >>> On Tue, Nov 24, 2009 at 8:52 AM, Jeff Whaley >> jwhaley@datacast.com>> wrote: >>> >>> I=92m curious about the engine mount style you guys are using with this >>> voltage drop situation. >>> >>> I can=92t imagine this problem occurring with the bed-mount/aluminum pl= ate >>> between the oil pan and engine block configuration. >>> >>> Surely a 3/8=94 or =BD=94 plate of aluminum and 20 bolts will conduct f= rom >>> housing to housing? - unless maybe it was anodized? >>> >>> Jeff >>> >>> *From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net>> flyrotary@lancaironline.net>] *On Behalf Of *Mark Steitle >>> *Sent:* Monday, November 23, 2009 4:41 PM >>> *To:* Rotary motors in aircraft >>> *Subject:* [FlyRotary] Re: No start >>> >>> Steve, >>> >>> Glad you got things figured out (we were running out of suggestions). >>> Sure gives one a good feeling after battling a problem for so long. BTW= , I >>> have two grounds on my engine. One is to the front cover, one to the fr= ont >>> side housing. I'll check into moving one up to the starter. >>> >>> Mark >>> >>> On Mon, Nov 23, 2009 at 3:33 PM, Steve Brooks >> cozy4pilot@gmail.com>> wrote: >>> >>> Al & Mark, >>> I would say that many people may have their ground to the engine block. >>> Mine has been that way since I built the plane, and worked fine for thr= ee or >>> four years before I started having an issue. >>> >>> I had to order a couple of new crimp connectors, so that I can make a >>> longer ground cable. Hopefully they will arrive before Thanksgiving, so= that >>> I can get it all hooked up over the long weekend. >>> >>> Steve Brooks >>> >>> >>> Al Gietzen wrote: >>> >>> >>> Steve, >>> >>> I read your other post on what you discovered regarding your bad ground= . >>> I wonder how many of us have our engine grounds tied to a bolt near the >>> front cover or end housing? (Mine does...) >>> >>> Mark S. >>> >>> Mine does as well =96 bolts to the front cover. I have never had a star= ting >>> issue, but I have followed this discussion with interest because a coup= le of >>> years ago I did a starting spark check and found the sparks considerabl= y >>> weaker than the mode 8 (or whatever) check. I just assumed it was due t= o the >>> voltage drawdown when the starter was running. Now it=92s worth another= look. >>> >>> I recall giving it some thought when doing the wiring (My EC/EM manuals >>> apparently predated Tracy recommended wiring diagram). I concluded that= the >>> various things bolted to the engine, like the manifolds, would provide = good >>> conduction paths regardless of the sealing between layers =96 and the 2= 0B has >>> a couple more layers. Both my intake and exhaust flanges are continuous= and >>> connect all the layers, and there are other things making the connectio= n to >>> the front cover, so this would be less of an issue compared to an >>> installation having separate flanges to each housing. >>> >>> Anyway, Steve; I=92m glad you found the problem. And thanks; it=92s a h= elp to >>> the rotary community, and again proves the value of a list such as this= . >>> >>> Al G >>> >>> >>> >>> -- >>> Homepage: http://www.flyrotary.com/ >>> Archive and UnSub: >>> http://mail.lancaironline.net:81/lists/flyrotary/List.html >>> >>> >> >> -- >> Homepage: http://www.flyrotary.com/ >> Archive and UnSub: >> http://mail.lancaironline.net:81/lists/flyrotary/List.html >> >> > > -- > Homepage: http://www.flyrotary.com/ > Archive and UnSub: > http://mail.lancaironline.net:81/lists/flyrotary/List.html > --0016e6d7eea0d7843604793606d7 Content-Type: text/html; charset=windows-1252 Content-Transfer-Encoding: quoted-printable Finn,
No, the shielded cable for the CAS is grounded on the EC-2 end onl= y.

Steve

On Wed, Nov 25, 2009 at 1= 0:44 AM, Finn Lassen <finn.lassen@verizon.net> wrote:
Does the CAS wiri= ng have a shield grounded at both ends?

Realize that when your main ground path to the starter was bad the current = would find alternative paths. If on of those paths were CAS wiring it would= introduce a voltage drop in that wiring, just like inserting the 1.5 volt = battery...

Finn

Steve Brooks wrote:
Jeff,
In my case, which is a pusher, my aft battery sits just inside the firewall= on top of the wing spar. I have #10 wires that connect from the batery ter= minals to feed the power and fround buss for the fuel puels, coils, fuel in= jectors, EC-2, etc. I have two 1/0 AWG cables that also connect to the batt= ery terminals. The positive runs back tot he starter, and is about 6 feet l= ong. The negative did run to one of the tapped holes for the A/C compressor= on the front engine housing. The ground is about 4 ft long currently. I am= going to remove that cable and run the ground from the battery to one of t= he starter mounting bolts, which will also make it about 6 ft long.

I also find it hard to believe that given all of the bolts in the mounting = plate, and the torsion bolts through the engine, that it wouldn't be a = really good conductor, but I would apparently be mistaken. I am not exactly= clear on how it interferrs with the CAS signal, but it does. My ground was= mounted just below the CAS about 8 inches, so perhaps that has something t= o do with it. It works fine there though for several years, before I starte= d having difficulty starting the engine.


Regards,
Steve Brooks
Cozy MKIV
Turbo rotary

Jeff Whaley wrote:

Good point on the anodizing Tracy; also a .005=94 layer of silicone isn=92t= conductive either, even with bare aluminum =96 conduction is made through = the bolts and not the entire mating surface of the plate. The math checks o= ut too. I=92m still curious about their specific setups though; I can see h= ow a stack of aluminum/iron/aluminum, etc with a layer of hylomar in betwee= n each stack might not be the best conductor =96 the sub-mount plate has to= help.

In my setup the battery is behind the cabin for weight and balance consider= ations. Ground is made to a steel tube frame with about 1 foot of #1 weldin= g cable; Positive runs through Master relay under the floor to firewall wit= h about 6 feet of same #1 welding cable, then another 2.5 feet to starter. = The engine ground is via stainless braid from front iron to engine mount ha= rdware at the firewall/airframe. So if the starter current path is from pos= t to post on the battery, then in my case it has to be close to 16 feet! I= =92ve never had any starting problems, but it would be interesting to see i= f an extra ground strap from starter bracket back to the airframe makes the= starter spin faster or engine fire sooner =85 will test that and post resu= lts.

Jeff

*From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net] *On Behalf= Of *Tracy Crook
*Sent:* Tuesday, November 24, 2009 9:43 AM
*To:* Rotary motors in aircraft
*Subject:* [FlyRotary] Re: No start

I doubt anodizing is a factor. Keep in mind that the starter we use is a li= ght duty one but its rating is 1.2 KW. With a typical cranking voltage of 1= 0 volts, that's 120 amps. With that kind of current, the only logical r= outing of the ground cable is as directly to the load as possible.

Do the math. At that current level, it only takes about .008 ohms to drop y= our working voltage a full 1 volt. That's 10% of your cranking power lo= st. Rotaries are especially sensitive to cranking speed because they lose m= ore compression than piston engines at low speed. Low compression makes sta= rting more difficult. Losses in this circuit must be minimized for many rea= sons. Also note that the ground connection point that many have said they a= re using goes very near the crank sensor and its wiring. This proximity mak= es inductive coupling into the CAS circuit more likely.

Add all these factors up and it is not surprising that many builders have s= tarting problems.

Tracy

On Tue, Nov 24, 2009 at 8:52 AM, Jeff Whaley <jwhaley@datacast.com <mailto:jwhaley@datacast.com= >> wrote:

I=92m curious about the engine mount style you guys are using with this vol= tage drop situation.

I can=92t imagine this problem occurring with the bed-mount/aluminum plate = between the oil pan and engine block configuration.

Surely a 3/8=94 or =BD=94 plate of aluminum and 20 bolts will conduct from = housing to housing? - unless maybe it was anodized?

Jeff

*From:* Rotary motors in aircraft [mailto:flyrotary@lancaironline.net <mailto:= flyrotary@= lancaironline.net>] *On Behalf Of *Mark Steitle
*Sent:* Monday, November 23, 2009 4:41 PM
*To:* Rotary motors in aircraft
*Subject:* [FlyRotary] Re: No start

Steve,

Glad you got things figured out (we were running out of suggestions). Sure = gives one a good feeling after battling a problem for so long. BTW, I have = two grounds on my engine. One is to the front cover, one to the front side = housing. I'll check into moving one up to the starter.

Mark

On Mon, Nov 23, 2009 at 3:33 PM, Steve Brooks <cozy4pilot@gmail.com <mailto:cozy4pilot@gmail.com>> wrote:

Al & Mark,
I would say that many people may have their ground to the engine block. Min= e has been that way since I built the plane, and worked fine for three or f= our years before I started having an issue.

I had to order a couple of new crimp connectors, so that I can make a longe= r ground cable. Hopefully they will arrive before Thanksgiving, so that I c= an get it all hooked up over the long weekend.

Steve Brooks


Al Gietzen wrote:


Steve,

I read your other post on what you discovered regarding your bad ground. I = wonder how many of us have our engine grounds tied to a bolt near the front= cover or end housing? (Mine does...)

Mark S.

Mine does as well =96 bolts to the front cover. I have never had a starting= issue, but I have followed this discussion with interest because a couple = of years ago I did a starting spark check and found the sparks considerably= weaker than the mode 8 (or whatever) check. I just assumed it was due to t= he voltage drawdown when the starter was running. Now it=92s worth another = look.

I recall giving it some thought when doing the wiring (My EC/EM manuals app= arently predated Tracy recommended wiring diagram). I concluded that the va= rious things bolted to the engine, like the manifolds, would provide good c= onduction paths regardless of the sealing between layers =96 and the 20B ha= s a couple more layers. Both my intake and exhaust flanges are continuous a= nd connect all the layers, and there are other things making the connection= to the front cover, so this would be less of an issue compared to an insta= llation having separate flanges to each housing.

Anyway, Steve; I=92m glad you found the problem. And thanks; it=92s a help = to the rotary community, and again proves the value of a list such as this.=

Al G



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