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10-11-2017, 06:18 PM
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Join Date: Mar 2006
Location: Newport, TN
Posts: 7,496
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Quote:
Originally Posted by krw5927
Why would someone who has not had an issue have any cause to complain?  We know what you mean though.
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I really need to proof read my phone postings! Thanks, I have edited my OP....
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10-11-2017, 06:24 PM
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Join Date: Apr 2010
Location: Clinton, Indiana
Posts: 996
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Wiring issue primer ?
I have two Pmags and two CPI . This tread has been extremely stimulating. That said, it appears the bottom line issue affecting CPI reliability is wiring termination failures ( ignoring errors ) , i.e. Corrosion, vibration etc. So, perhaps Ross or someone would start a separate thread on optimizing wiring termination from corrosion, vibration, etc ???
__________________
Larry DeCamp
RV-3B flying w/7:1 0320 / carb / Pmags / Catto 3b / digital steam
RV-4 fastback w/ Superior roller 360/AFP/G3X/CPI/Catto3b
Clinton, IN
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10-11-2017, 08:38 PM
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Join Date: Mar 2005
Location: Calgary, Canada
Posts: 5,766
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Quote:
Originally Posted by Larry DeCamp
I have two Pmags and two CPI . This tread has been extremely stimulating. That said, it appears the bottom line issue affecting CPI reliability is wiring termination failures ( ignoring errors ) , i.e. Corrosion, vibration etc. So, perhaps Ross or someone would start a separate thread on optimizing wiring termination from corrosion, vibration, etc ???
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We've used the same type of connectors on the CPI and our ECUs for the last 15 years and MILLIONS of hours collectively in environments much harsher vibration wise than the aviation environment (Baja 1000 races). When the wires are collected and tie wrapped at the controller end and supported as we recommend, I've yet to see or hear of a broken wire at the connector. Since our controllers must be cabin mounted, they don't see moisture, therefore corrosion is a non-issue in aircraft. Everything FF has a strain relieved, waterproof connector.
Best practice on wiring tells us to support bundles from movement or physical strain. Done properly, we simply don't see wiring failures at either end. Our old shop car had SDS on it for 19 years and about 5000 hours. Coarse old engine with fair vibration, heavily salted roads in the winter, no particular care in support or strain relief. No wiring breakages or corrosion in that time.
The Hall sensor is one piece with the cable, no interim connectors.
We just don't see problems here.
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10-11-2017, 08:51 PM
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Join Date: Jan 2005
Location: SC
Posts: 12,887
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Quote:
Originally Posted by krw5927
Is this entirely true, considering the apparently critical external wire connection to engine ground?
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Yep, they will continue to fire.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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10-11-2017, 08:53 PM
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Join Date: Jan 2005
Location: SC
Posts: 12,887
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Quote:
Originally Posted by Toobuilder
Do the sparks keep flowing when the coil wires (primary side) fail?
(No need to answer Bill, we know the answer)
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No, but that's why you have two independent ignitions.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html
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10-11-2017, 09:07 PM
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Join Date: Jul 2009
Location: Mojave
Posts: 4,652
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Quote:
Originally Posted by N941WR
No, but that's why you have two independent ignitions.
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Seeing you are a supplier of ignition products to the consumer, I'm going to assume that what you really meant to say was: "...No, but that's why you choose the proper connectors and follow established wiring practices..."
Mitigation of the hazard is much more productive than relying on a fallback.
__________________
WARNING! Incorrect design and/or fabrication of aircraft and/or components may result in injury or death. Information presented in this post is based on my own experience - Reader has sole responsibility for determining accuracy or suitability for use.
Michael Robinson
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Harmon Rocket II -SDS EFI
RV-8 - SDS CPI
1940 Taylorcraft BL-65
1984 L39C
Last edited by Toobuilder : 10-11-2017 at 09:31 PM.
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10-11-2017, 09:48 PM
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Join Date: Oct 2005
Location: Melbourne, Australia
Posts: 1,868
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Quote:
Originally Posted by Brantel
My impression is that you are more likely to see a public complaint from someone that has an issue than a positive post by someone who has not.
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That may be true, but it doesn't undermine the theory that faults in experimental ignition systems will be largely under-reported by users for numerous reasons. As I said previously there is no obligation on users to publicly report faults and quite a bit of incentive to not do so.
Brian, if you personally have a problem with one of your PMAGs, are you going to report that fault on VansAirforce...probably not if it's not in your personal interest to do so. I mean, there's no moral or legal duty of disclosure.
I have a LightSpeed Plasma 11 on one side (magneto on the other....I'm with Vic Syracuse on this). I'd have to think very seriously about publicly whinging about a fault in my EI on VansAirforce and then going cap in hand to Klaus at some time in the future for support.
I mean, when you buy an EI from a very small, virtually backyard company like EMAG or LightSpeed you're not just buying a product....you're hopping into bed with them for good or for bad.
Incidentally I think that the transparency shown by Ross Farnham regarding SDS products in post #88 is just so refreshing. I'm sure his honesty will attract more purchasers to his CPI ignition system. I'm impressed.
__________________
You’re only as good as your last landing 
Bob Barrow
RV7A
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10-12-2017, 01:02 AM
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Join Date: Feb 2005
Location: LSGY
Posts: 3,198
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NASA form
Quote:
Originally Posted by Captain Avgas
...Brian, if you personally have a problem with one of your PMAGs, are you going to report that fault on VansAirforce...probably not if it's not in your personal interest to do so. I mean, there's no moral or legal duty of disclosure....
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Perhaps we need a NASA form for suppliers. 
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10-12-2017, 03:54 AM
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Join Date: Mar 2006
Location: Newport, TN
Posts: 7,496
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Quote:
Originally Posted by Captain Avgas
Brian, if you personally have a problem with one of your PMAGs, are you going to report that fault on VansAirforce...probably not if it's not in your personal interest to do so. I mean, there's no moral or legal duty of disclosure.
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Absolutely and I have done so on other products as well. The best manufacturers take the criticism and do something about it.
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10-12-2017, 06:39 AM
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Join Date: Oct 2005
Location: 08A
Posts: 9,500
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Quote:
Originally Posted by N941WR
Dan, as always, you bring in good logic; however, once the P-mags are spinning, one or more of its wires can fail and it will keep the sparks flowing. (Unless the failure is in a plug wire.) How many wires can fail in a Distributed system before it stops producing sparks?
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Fair point Bill.
Recall wires can fail open, or shorted. I typically make a list with each wire represented and think about both open and grounded failure modes, ignoring the probability of failure, and initially only considering what happens if it does fail. Example here: http://www.vansairforce.com/communit...8&postcount=63
A wire list for the CPI says shorting or opening almost any pin will shut it down. On the other hand, it does not appear any open or short can make it do strange things. Put another way, it works or it is dead.
In the case of the P-mag, the result of an open or short on a few of the wires is obvious. However, I don't know enough about the p-mag to be sure what happens when some of the wires are opened or shorted, notably software driven events.
Pin 1: I think you just stated the system works with this one open. If shorted is normal and open doesn't matter, the logical question becomes "Why is it there?" Back up for case ground to engine block?
Pins 2 and 3: Without an EIC, an open shifts timing aprox 5 degrees advanced. Field experience says that's probably not critical at WOT with 100LL fuel, just higher CHT. I have no idea what the result might be by shorting either 2 or 3 to ground, with or without the EIC. How does the EIC drive a timing shift with these wires?
Pin 4: Obviously a short kills the mag, like any mag.
Pin 5: An open above 800 RPM or so is no issue; that's the whole point of the internal generator. What about a short to ground?
Pin 6: Tach lead. Assumed to have no effect on the P-mag alone, open or shorted. Does the EIC use the tach signal for anything other than an RPM display?
Quote:
Originally Posted by N941WR
No, but that's why you have two independent ignitions.
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A perfectly reasonable answer. It's an extension of the above; list the possible failures, and consider the result of each. Here the result of all failures is the ignition doesn't work, but the flight continues, as we have two of them.
__________________
Dan Horton
RV-8 SS
Barrett IO-390
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