---------------------------------------------------------- AeroElectric-List Digest Archive --- Total Messages Posted Sat 01/27/18: 6 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 03:44 AM - Re: Re: Starter Contactor location on a Long-EZ (Michael Garmon) 2. 07:17 AM - Ground protection (Richard Girard) 3. 07:58 AM - Re: Starter Contactor location on a Long-EZ (Airdog77) 4. 08:32 AM - Re: Re: Starter Contactor location on a Long-EZ (Dj Merrill) 5. 11:24 AM - Re: Re: Starter Contactor location on a Long-EZ (don van santen) 6. 01:05 PM - Re: Starter Contactor location on a Long-EZ (Airdog77) ________________________________ Message 1 _____________________________________ Time: 03:44:39 AM PST US From: Michael Garmon Subject: Re: AeroElectric-List: Re: Starter Contactor location on a Long-EZ Bob, There is an account of the incident on Brian Deford=99s website locate d at http://deford.com/cozy/fire.html. I am also considering installing the starter solenoid on the inside (cabin s ide) of the firewall. I also plan on protecting alternator B leads with fusi ble links sized to protect the wire ( larger than the alternator capacity). I n this way, any wire crossing the firewall will be protected. Michael Garmon Cozy Mk IV Houston, TX Sent from my iPad > On Jan 26, 2018, at 6:56 PM, Robert L. Nuckolls, III wrote: > > At 05:08 PM 1/26/2018, you wrote: >> >> Bob, >> >> Roger... I'll go back and take a deeper look at all this. > > Is there a published failure analysis of > what transpired in the unhappy event? > > A significant proportion of my career in aviation > focused on what-went-wrong-and-why. In hind-sight, > I wish I had kept a journal on the various inquiries, > facts found and resolution of root causes. I > can state with confidence that a majority of > failure events had root cause in 'somebody > didn't read/understand some bit of history in > design or application. > > A few instances, like the sticking trim relays on the > Beechjet, involved new discoveries. But most unhappy > events were founded on inattention to rudimentary > details. I've worked some exceedingly expensive > problems ($millions$) that had roots in $100 > decisions . . . > > Whatever you decide to do with your airplane, > it NEVER hurts to take some pictures, post to > the List and ask questions. The most elegant > solutions are invariably a team effort by > competent observers. You'll have a hard time > finding a more capable group than right here . . . > > Bob . . . ________________________________ Message 2 _____________________________________ Time: 07:17:23 AM PST US From: Richard Girard Subject: AeroElectric-List: Ground protection After watching a friends bike go up in flames from a short I did some thinking about the situation. I decided that I wanted some protection from a similar fate and came up with a solution. I put a 50 amp switch in the ground line from the battery to the frame. The logic was that with this arrangement I could kill any short circuit by throwing a single switch rather than having to find the offending wire. Located in a covered location it was also cheap theft insurance. I just switched it off when I parked. In 20 years I had one switch failure, most likely a victim of the "Vibraglide's" rigid engine mounting setting the whole bike into spasms. On the road it was a momentary annoyance to remove the seat, take the switch out of the line and motor on to the auto parts store. Airborne it probably wouldn't be as easy. It seems to have been a valid solution for the Harley but is it good practice otherwise? Rick Girard -- =9CBlessed are the cracked, for they shall let in the light.=9D Groucho Marx Virus-free. www.avg.com <#DAB4FAD8-2DD7-40BB-A1B8-4E2AA1F9FDF2> ________________________________ Message 3 _____________________________________ Time: 07:58:25 AM PST US Subject: AeroElectric-List: Re: Starter Contactor location on a Long-EZ From: "Airdog77" Bob, I have to admit I'm puzzled on what appears to be sticking to the standard convention of mounting the starter contactor/solenoid on the firewall of a pusher aircraft when the A-to-Z of the power distribution configuration is different than a traditional tractor airplane. If we look at the different configurations, which I spelled out in asking advice on this from some canard builder/fliers, it looks like this: 1. Tractor: FIREWALL >> Battery >> Battery Contactor >> shorter big wire >> Starter Contactor >> Starter 2. "Standard" Pusher: Battery >> Battery Contactor >> longer big wire >> FIREWALL >> Starter Contactor >> Starter 3. "New" Cozy style: Battery >> Battery Contactor >> longer big wire >> Starter Contactor >> FIREWALL >> Starter Not to be critical of Brian in any way, and in the discussion I discovered in support of placing the starter solenoid on the cold side of the firewall, was a point made that he "didn't turn off the master" which controls the power flow through the big power cable, as is a prominent feature of #2 above. I understand doing analysis on past events, and looking at standard practices in an attempt to mitigate potential issues (which is exactly what I'm attempting here), but Brian's scenario isn't the only reported instance of smoking wires in a pusher, it's simply the most tragic (that I know of). The second point in this discussion is that if control of the electron flow through the big cable ends at the cold side of the firewall (as is proposed), and the only (initial) action that results in electrons flowing across the firewall boundary is when the starter button is depressed... then very most likely only one action is required if there is any malcontent going on "back there" and that is simply to STOP pressing the starter button. Then Step 2: TURN OFF THE MASTER is moved from the critical column to the probably a good idea column. Moreover, the ancillary logistical benefits of moving the starter contactor to the cold/forward side of the firewall in routing wires is quite significant. It simply makes for running less wires through the firewall, wire runs to the Hall Effect sensor for both the primary and SD-8 backup alternators are optimized, and it places more items in the rather empty Hell Hole area and gets them off a very crowded firewall. In short, it just really appears on the face of it to make for an easier install and a safer operational setup. And again, going back to my original statement, I'm not really sure why the starter contactor/solenoid should be on the hot side of the firewall in a pusher airplane. Moreover, in looking at the pros/cons for moving the starter solenoid to the cold side, the pros vastly outweigh any cons that I could find. Not that I am in any way the most knowledgeable on this stuff, but from what I know, have researched and discussed it appears to be the best option thus far. Regards, Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=477632#477632 ________________________________ Message 4 _____________________________________ Time: 08:32:47 AM PST US Subject: Re: AeroElectric-List: Re: Starter Contactor location on a Long-EZ From: Dj Merrill On 1/27/2018 10:57 AM, Airdog77 wrote: > 2. "Standard" Pusher: Battery >> Battery Contactor >> longer big wire >> FIREWALL >> Starter Contactor >> Starter > > 3. "New" Cozy style: Battery >> Battery Contactor >> longer big wire >> Starter Contactor >> FIREWALL >> Starter Hi Wade, FWIW, with my battery in the tail, the system in my tractor config Glastar is the same as #2. I don't see any immediate reason why #3 should not work. In either case, the protections of the big wire going through the firewall should be the same. I also agree with the other folks that if the installation is done properly, #2 should also be fine. My Glastar has been flying with this configuration for 18 years, and other aircraft far longer. From an electrical perspective, I do not see any differences between a pusher versus a tractor. It is your airplane, and you need to do what will make you feel comfortable, IMHO. -Dj -- Dj Merrill - N1JOV - EAA Chapter 87 Currently Flying: Glastar Previously: Cessna 150 - Glasair 1 FT - Grumman AA1B ________________________________ Message 5 _____________________________________ Time: 11:24:00 AM PST US From: don van santen Subject: Re: AeroElectric-List: Re: Starter Contactor location on a Long-EZ Wade, are you forgetting the two alternator "b" leads? In the contactor on the cold side they both have to pass through the firewall. In the std setup they connect to the hot side of the starter contactor. Don On Saturday, January 27, 2018, Airdog77 wrote: > > Bob, > > I have to admit I'm puzzled on what appears to be sticking to the standard convention of mounting the starter contactor/solenoid on the firewall of a pusher aircraft when the A-to-Z of the power distribution configuration is different than a traditional tractor airplane. > > If we look at the different configurations, which I spelled out in asking advice on this from some canard builder/fliers, it looks like this: > > 1. Tractor: FIREWALL >> Battery >> Battery Contactor >> shorter big wire >> Starter Contactor >> Starter > > 2. "Standard" Pusher: Battery >> Battery Contactor >> longer big wire >> FIREWALL >> Starter Contactor >> Starter > > 3. "New" Cozy style: Battery >> Battery Contactor >> longer big wire >> Starter Contactor >> FIREWALL >> Starter > > Not to be critical of Brian in any way, and in the discussion I discovered in support of placing the starter solenoid on the cold side of the firewall, was a point made that he "didn't turn off the master" which controls the power flow through the big power cable, as is a prominent feature of #2 above. I understand doing analysis on past events, and looking at standard practices in an attempt to mitigate potential issues (which is exactly what I'm attempting here), but Brian's scenario isn't the only reported instance of smoking wires in a pusher, it's simply the most tragic (that I know of). > > The second point in this discussion is that if control of the electron flow through the big cable ends at the cold side of the firewall (as is proposed), and the only (initial) action that results in electrons flowing across the firewall boundary is when the starter button is depressed... then very most likely only one action is required if there is any malcontent going on "back there" and that is simply to STOP pressing the starter button. Then Step 2: TURN OFF THE MASTER is moved from the critical column to the probably a good idea column. > > Moreover, the ancillary logistical benefits of moving the starter contactor to the cold/forward side of the firewall in routing wires is quite significant. It simply makes for running less wires through the firewall, wire runs to the Hall Effect sensor for both the primary and SD-8 backup alternators are optimized, and it places more items in the rather empty Hell Hole area and gets them off a very crowded firewall. In short, it just really appears on the face of it to make for an easier install and a safer operational setup. > > And again, going back to my original statement, I'm not really sure why the starter contactor/solenoid should be on the hot side of the firewall in a pusher airplane. Moreover, in looking at the pros/cons for moving the starter solenoid to the cold side, the pros vastly outweigh any cons that I could find. Not that I am in any way the most knowledgeable on this stuff, but from what I know, have researched and discussed it appears to be the best option thus far. > > Regards, > Wade > > -------- > Airdog > Wade Parton > Building Long-EZ N916WP > www.longezpush.com > > > Read this topic online here: > > http://forums.matronics.com/viewtopic.php?p=477632#477632 > > ________________________________ Message 6 _____________________________________ Time: 01:05:14 PM PST US Subject: AeroElectric-List: Re: Starter Contactor location on a Long-EZ From: "Airdog77" Hi Don, As for big wires coming off the Starter Contactor I have an 8 AWG B lead from the alternator that connects to the same lug on the hot side of the starter contactor. On the other side of the starter contactor I have a 6 AWG lead going to the starter. Yes, I do have an 18 AWG F-lead that also comes off the alternator that transitions through the firewall back to the Voltage Regulator, but I was looking primarily at the heavy gauge wires through the firewall. I understand the 8 AWG wire traversing the firewall is still on the hot side of the contactor, connected to the same post as my mega cable coming from the nose, but it is a lot more manageable. Thanks, Wade -------- Airdog Wade Parton Building Long-EZ N916WP www.longezpush.com Read this topic online here: http://forums.matronics.com/viewtopic.php?p=477636#477636 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message aeroelectric-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/AeroElectric-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/aeroelectric-list Browse Digests http://www.matronics.com/digest/aeroelectric-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.