IMO, the first EI is very much worthwhile, but for me the second ignition system has to be simple and reliable. A single well maintained magneto does that with no loss of performance or fuel economy, nor added weight from standby batteries or alternators.
Just one guys opinion
Tim Andres
Im suprised there haven't been more replies to this thread.
Im moving to 1 CPI system and my old friend Slick, who has never let me down. Feel free to read between the lines.
IMO, the first EI is very much worthwhile, but for me, the second ignition system has to be simple and reliable. A single well maintained magneto does that with no loss of performance or fuel economy, nor added weight from standby batteries or alternators.
Just one guys opinion
Tim Andres
I value and appreciate your opinion Tim. Looks like you have had an opportunity to test a variety of ignitions and have a good understanding of what works and why.
In your newest configuration is the Slick a backup to the CPI in case the electrons stop flowing for some reason or do you have second battery, second alternator or something else?
A friend of mine has a 2-year old RV-8. He installed a P-mag and a Slick. The Slick failed catastrophically at 300+ hours requiring an engine tear down. He is replacing the Slick with a second P-mag. Anecdotal, yes - but one can't assume that the old faithful mechanical system is the most reliable. Also, P-Mags are electronic but no more dependent on battery/alternator (once running) than a magneto due to their internal power generation.
My Rv-14 has dual P-mags.
Im suprised there haven't been more replies to this thread...
...Unless you're a very good test pilot or have access to a Dyno, you will not be able to measure the difference with a second EI, at least I couldn't. And I'm talking about measured fuel burn and performance, not subjective "It feels smoother" or being impressed by the RPM delta when doing a mag test vs EI...
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I was told one "downside" to doing so was the loss of being able to hand-prop the aircraft if the battery was dead...which wasn't a downside to me as I don't ever plan on hand-propping it...I will either charge or replace the battery. (There's also a way to get the P-mag to fire with a 9v battery if you REALLY want to hand-prop it..)
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I'll step in an mention that there is no scheduled maintenance with the CPI/SDS ignition systems- no drive gears or shaft bearings to inspect or fail. You can toss the $3 plugs every annual when you do a compression check and maybe replace the plug wires every 5 years/1000 hours if you like- about $150 for an all new harness with the recommended MSD parts on all 8 plugs.
Something to note a very nice Lanceair crash here in Australia. Done up with all the latest equipment including duel electronic ignition.
Reason for the accident was the alternator fan belt let go just after take-off and took out the flywheel pick-ups for the ignition timing resulting in that noisy silence.
I am a believer in one electronic ignition and one mag, as I think it provides the best all around solution, both in economies and in redundancy. Having been in technology for most of my life, I am a believer in backups.
Yes, the mag could be a weak point, and there are always the stories about catastrophic failures of mags. The weak point of the mag is the impulse coupling, and I leave that part off. The argument about needing to be able to hand prop it doesn't really hold a lot of weight, as there are nice compact jump start battery packs that you can carry these days, and it's a lot safer than hand propping your aircraft. I have personally jump started IO-540's with them, I always have one in the back of my airplane, and I regularly charge it.
The 500 hour overhaul on a slick direct drive mag is really cheap, and you can do it yourself for less than $75.
Vic
Curious, for those who went electronic ignition.
How many electrical backup strategies do you have, and have you tested them?
Tim
The 500 hour overhaul on a slick direct drive mag is really cheap, and you can do it yourself for less than $75.
Vic
It was a Glasair and maintenance and workmanship lapses were found to be the main causes.
The maintenance labor and parts costs of mags are a big reason why so many are dumping one or both mags. Our EI has no moving parts other than the magnets attached to the crankshaft. With an epoxy potted coil pack, there are no things to suffer vibration failures as on mags, no spinning parts, no bearings, no wearing parts, the electronics are isolated from engine heat and vibration in the cabin.
Combine this spark hardware with reliable electronics having literally tens of millions of hours of real world validation on them and you have stuff which is far more reliable than mags with no maintenance required. One of our bench test ECUs had 145,000 hours on it when we changed it over to a newer spec model. It ran 24/7 for over 16 years.
Ross,
If I were not already half pregnant with an existing Pmag, you would be getting an order for a dual CPI. The only thing I had never considered was the risk of an alternator belt taking out the timing sensor but what are the odds of that? I love the looks of the quality of your components and the price!
Question for Ross (SDS),
Is it possible to operate a dual SDS electronic Ignition system using only the EM-5 (dual channel) and the SDS LCD programmer (round controller), absent the SDS fuel injection system being full installed and operational?
The reason I ask is:
1. I want dual SDS EI now but don't want the rectangular CPI control modules.
2. I want the ability to eventually change over from my mechanical FI to a SDS FI system.
Titan IO-360.
I know the FI part of my statement is considered off topic/thread drift, so please forgive me.
The aircraft was Glassair 111 VH-USW and the ATSB final report does not really support the above statement.
. SNIP......So, for me the decision would be simple. I'll take the accessory case triggers for a 4-cyl, and crank triggers for a 540....SNIP.
Dan's logic is spot on.......So I'm left in the valley of waiting for the six cylinder pMag.
I know that this is directed at Ross, but the answer is "yes". I worked with a guy last year doing exactly that.
It doesn't support either statement. The report is a best guess as to cause; there was too much fire and impact damage to be sure of exactly what happened. Factually, the installation was non-standard, a single trigger for two ignition units. Duh.
Moving to belief as to cause, belt damage disconnecting the trigger wires is not an argument against EI, but rather an argument for better wire installation. My brothers, that's true of every wire in every EI brand, regardless of trigger location.
Ross, go ahead and design bolt-on armor for the trigger, something in machined billet robust enough that the wires can't be harmed with a Colt 45. It would cause joy among the concerned, and make a nice profit too.
At the other end, arguments against accessory drives are also weak, given that we have about 80 years of experience with them, with most of the fleet subject to AD for any prevalent failure. Mags and their associated couplers fail a lot, the accessory case drives not so much. Moving to EI, one might look at failure rates for the bearing and trigger components in the triggers themselves, just like the mags.
And there we find the detail which should determine crank-triggering vs accessory case triggering. In terms of mechanical design, a 4-cyl accessory case trigger is very simple, a shaft, two bearings, a wheel, and a pickup. However, all the 6-cyl accessory case pickups seem to require internal gearing, which brings new complications and quality control issues to the party. Plus the 6's are more prone to torsional vibration issues due to the longer crank. So, for me the decision would be simple. I'll take the accessory case triggers for a 4-cyl, and crank triggers for a 540.
All the moving parts in a basic 4-cyl trigger:
Question for Ross (SDS),
Is it possible to operate a dual SDS electronic Ignition system using only the EM-5 (dual channel) and the SDS LCD programmer (round controller), absent the SDS fuel injection system being full installed and operational?
The reason I ask is:
1. I want dual SDS EI now but don't want the rectangular CPI control modules.
2. I want the ability to eventually change over from my mechanical FI to a SDS FI system.
Titan IO-360.
I know the FI part of my statement is considered off topic/thread drift, so please forgive me.
The aircraft was Glassair 111 VH-USW and the ATSB final report does not really support the above statement.
The final ATSB report can be found at:
http://www.atsb.gov.au/publications/investigation_reports/2013/aair/ao-2013-221/
It doesn't support either statement. The report is a best guess as to cause; there was too much fire and impact damage to be sure of exactly what happened. Factually, the installation was non-standard, a single trigger for two ignition units. Duh.
Moving to belief as to cause, belt damage disconnecting the trigger wires is not an argument against EI, but rather an argument for better wire installation. My brothers, that's true of every wire in every EI brand, regardless of trigger location.
Ross, go ahead and design bolt-on armor for the trigger, something in machined billet robust enough that the wires can't be harmed with a Colt 45. It would cause joy among the concerned, and make a nice profit too.
At the other end, arguments against accessory drives are also weak, given that we have about 80 years of experience with them, with most of the fleet subject to AD for any prevalent failure. Mags and their associated couplers fail a lot, the accessory case drives not so much. Moving to EI, one might look at failure rates for the bearing and trigger components in the triggers themselves, just like the mags.
And there we find the detail which should determine crank-triggering vs accessory case triggering. In terms of mechanical design, a 4-cyl accessory case trigger is very simple, a shaft, two bearings, a wheel, and a pickup. However, all the 6-cyl accessory case pickups seem to require internal gearing, which brings new complications and quality control issues to the party. Plus the 6's are more prone to torsional vibration issues due to the longer crank. So, for me the decision would be simple. I'll take the accessory case triggers for a 4-cyl, and crank triggers for a 540.
All the moving parts in a basic 4-cyl trigger:
Thanks Michael.
Would two SDS LCD programmers, and one SDS EM-5 (Dual Channel) be required to operate two SDS EI's as previously described?
..., or could two SDS EI's be operated from one dual channel EM-5 and one LCD SDS programmer?
Michael, any chance I could call you to discuss your experience with SDS?
Thanks
(SDS crank sensor) belt vulnerability is a non issue. The mount and sensor are **** for stout and the wiring can easily be armored.
Just need one programmer to operate dual EM-5 ECUs for dual EI or dual EFI/EI.
Is the the shaft, two bearings, and wheel, depicted and described for 4 cylinder trigger/pickup, a custom fabricated part or is that something that a part that can be procured through AC parts sources and then be modified to work?
It somewhat resembles a B&C SD 8 Alternator. I wonder what those look like under the bell cover. Seems like it (B&C alt) could do double duty and do the crank position sensor job aside from generating electrons.