IO-540 Electronic Ignition

[schu]

When thinking about electric ignition, the most complex part is keeping it powered. This leads most people down the P-mag road, but there is no way I'd buy anything that had prior issues, followed by a multi year delay, that requires 100 hour inspection.

This only leaves 3 options:

1. Using one mag and one EI. I haven't decided if I like this idea.

2. Using Surefly or SDS CPI-1 (or something else) and making sure that you have redundant power (with at least one of them pathed to a secondary battery that can be isolated).

3. Using the SDS CPI-2 and connecting a small led acid battery to be dedicated to this task.

A lot of people think they have redundant power, but their system can't survive a large short to ground, contactor failure, or connector failure. From a wiring standpoint using a CPI2 is probably easier because it isolates the backup battery from the rest of the system by default. I'd go that way if I had room on my panel for the head and a secondary alternator for the pump pad.

From a plug perspective, I have no issue with NGK plugs, they are great! It's the adapters I'm not so hot on....

[robcaldwell]

When I was considering a full electronic ignition system on my IO-540, the TCW battery backup seemed like a viable choice for SureFly or Light Speed EI (I don't know much about SDS).

https://www.tcwtech.com/product/integrated-battery-back-up-system-ibbs/?v=7516fd43adaa

If I decide to eventually use auto plugs, I am also concerned about the adapters. Has anyone used the adapters from Light Speed?

https://lightspeed-aero.com/Products/Sparkplugs.htm

[schu]

I’m not sure if that is supported, ignition systems are noisy and they seem to be aware of that mode of failure as the manual states:

“ The IBBS system is suitable for use with equipment such as Garmin GNS and GTN series navigators, G3X series of avionics, Grand Rapids Technologies EFIS systems, Advanced Flight Systems EFIS, Dynon EFIS, and MGL EFIS, TruTrak Autopilots and EFIS, Trio Autopilots.

No other uses of the IBBS system are permitted except for those identified in this installation manual.“

The only way I can think of to have total redundancy that would survive master contractor failure, short to ground, and fuse issues is to use a CPI-2 which maintains its own backup battery, or to use a secondary alternator that has its own isolated battery/electrical system and put one EI unit on each system.

[schu]

I suppose you could put a one way power diode between the main electrical system and a backup battery and power the secondary ignition system through a switch on the far side of the diode. When you startup you turn on the primary and secondary ignition switch and should you have a main bus power issue or short to ground it shouldn't affect the secondary battery or secondary ignition system on the far side of the diode.

[Battson]

With SIM surefly, the backup battery only needs to be equivalent to a few "D cells". They can be tiny and still allow you to fly for hours. A real non-issue.

When you think backup battery, it is NOT dual Oddessy's weighing 7kg each. My spare is only a few hundred grams, a small and relatively cheap Li-ion.

[schu]

Do you have a make and model on your cheap Li-ion battery? Usually they need some charging circuit around them to allow the alternator to maintain them.

[edmo]

Thanks for that insight. I have also been seeing some of the smaller batteries that are intended as a backup for the glass displays that might work well. I was originally thinking something motorcycle battery sized might be required.

[rv8bldr]

I'm liking the looks of the SureFly. Can anyone comment on the relative advantages/disadvantages of the SureFly over the PMag? The PMag is actually a little cheaper but not enough that it would trump any technical/safety issues. I have a newly overhauled O-540 (235HP) with Continental (Bendix) mags. I want to replace at least one of them with either the SureFly or PMag.

[schu]

pmag = 100 hour inspections
surefly requires ship power

Neither are programable. If I do electric ignition it will be an SDS CPI as I would want a LOP advance switch and the CPI2 allows for failover to a secondary electric system.

[robcaldwell]

Personally I would prefer the P Mag for its electrical independence. But I'm not there yet. The 100 hour inspection requirement makes me nervous, and inconvenienced.

[Bcone1381]

It's my understanding, (I have n0 experience, but have been studying this for years) that Pmag has very good customer service. There product is not certified, requires 100hr inspections for at least main bearing wear. The PMag guy at OSH told me that the Pmag drive gear receives vibration from the Lycoming engines. This is unpredictable (meaning some have more vibration than others) resulting in inconsistent wear and tear to there product, so the main bearing of the Pmag is to be checked every 100 hr. This check is not time consuming if you done without removing the entire Pmag. Basically, the inspector wiggles the main shaft, checking for slop.

Surefly is certified, and essentially installed and removed at engine overhaul. Surefly is powered from the aircraft's battery terminal.

[Battson]

I have found the customer service at Surefly to be some of the best I've experienced. I had my fair share of questions, it was easy to speak to their technical expert.
In terms of customer support, Brad at Pmag is a great guy, very friendly and quick to respond. The product has a great track record too.

I originally wanted a Pmag - the on-board power supply is a great simplification and a safety factor. With 20:20 hindsight, the second battery on the Surefly SIM is a non-issue.

Full disclosure:
People waited years for the Pmag (six cylinder) to be released, many gave up (including me after 5 years). The whole time Brad was telling me (and many others) that the product was only 6 to 12 months away from release. He was also accepting deposits the whole time. Three more years later (around 8 years total build-up), the product was finally released into the marketplace.
That is all I can offer about Pmag, and it's the only reason I ended up getting the SIM.

The issues with the SIM are:
1. The instruction manual has a few minor but important errors in it which can take a little figuring out during installation and when timing.
2. Timing the SIMs required removing a live wire from the power terminal and connecting it to the timing terminal, often resulting in your tool touching earthed parts and blowing a 5A fuse (until you learn to remove the fuse first). This can be annoying if you don't have a spare fuse...
3. Starting requires a fast spinning starter, else you can get an occasional weak kickback - although there are ways to work around this. The kickbacks are very weak and do not cause damage, they are just annoying. The root of this issue is tied to a "safety timeout" feature which they have included to prevent engine damage in case of an electrical failure. I am not sure if other manufacturers have ignored or perhaps done this differently.

[Nev]

I've installed two 6 cylinder PMags. I liked the concept, as Battson mentioned. I've also found Brad very good to deal with. I've already experienced one recall - something no one wants to deal with. Brad sent me an exchange pair out immediately and covered freight, so the turn time was about 10 days.

Installing them was straightforward. The manual could be better, but I figured it out. Typical of aircraft manuals, it's written by an engineer rather than a user. But that's a minor point. Timing is very easy, and very quick.

In terms of the 100 hour check, I've yet to confirm if my pair are affected. If they are, I need to disconnect one scat tube to access them. Then it's a 15 minute exercise. Certainly a small inconvenience. But it's probably the underlying reason behind the check that is more the worry.

In terms of redundancy, both PMAGs are powered by the battery, and if they lose that power source, they become powered by their internal alternators. To me, thats triple redundancy for the the power supply, and double redundancy for mechanical (same as Mags).

I haven't run the engine yet, so bear that in mind as you're reading this. I'll update once I'm flying and have something more concrete to report.

[Battson]

No single task in a 100hr check takes more than a quarter of an hour It's the sum of all the parts that takes 10 to 12 hours!

[rv8bldr]

Thanks a lot for the replies, guys. I really appreciate it.

Jon: Ya, I talked to Brad EVERY year at Oshkosh about the 6 cyl PMag and he always said "...probably November". It was to the point my wife asked after a few years ""um, isn't that what he said last year?"

I guess I must have been asleep as this 100 hr inspection thing on the PMag was a bit of a news flash. Of course, it doesn't sound onerous and the most I've ever flown in a year was with my RV-8 and that was about 100 hr, so this would probably be just another task during the aircraft annual.

I'm planning an IFR panel and will have a backup B&C alternator but I'm still not sure I want the device keeping the noise going up front to be reliant on electrons from the AC electrical system.

[Bcone1381]

This thread hits all the things I have been researching and considering over the past several years. A new piece of evidence has emerged that I've not considered. It seems to me that almost every pilot is happy with whatever choice they installed. So it is very likely that I will be happy irregardless of which I choose. At least three very good choices are available, no choice is right or wrong as long as the electrical infrastructure supports reasonable redundancy.

[John Bickham]

Ok, I'm getting close to making a decision to explore electronic ignition for my Barrows O-540. I've been sitting on the sidelines, waiting on other test pilots to evaluate the six cylinder P-mag! So, Nev is the only data point on the six cylinder p-mag that I know of so far. Any others?

Happy with your dual P-mags Nev?
I'll probably stay in the shallow end of the pool with only one P-mag initially.

[Nev]

Happy with your dual P-mags Nev?

Yes very happy with them so far John. They're one area that seem to have been completely trouble free, (along with the avionics). If I were starting over again, I would still do the same and install two PMAGs. I like that they've got internal backup alternators in them too, so in effect I think of it as triple redundancy in that if I lose the main battery power supply, both PMAGs should keep running. I guess in effect if you're comparing them to legacy mags then they would have double redundancy the same as mags do. The timing on them is very easy and quick to do too.

Just one thought, if you install one of each, and there was a product recall or AD, it would have the same effect whether you have one or two installed, and the likelihood of having a double failure (that would have to disable the backup) is probably commensurate with normal mags (I.e. very unlikely). So for me I didn't see any advantage to starting with one of each.

Hope this helps and also looking forward to seeing others experiences with PMAGs.

[John Bickham]

thanks Nev. Brad returned my call this evening, just after I finished my runup. Needed to go fly since the wx is fixin to shut us down for the week. Will call him back tomorrow. Would consider dual P-mags but my Avgas bill is a conflict!!