E-mag / P-mag vs magnetos

I'm interested in hearing opinions on the relative merits of pmag versus traditional mags. I've read the ads, but would like to get some unvarnished advice. Specifically, I'd like opinions on:

1. Performance. As I understand it, a mag does not have the advance capabilities of an electronic unit, and also produces a much weaker spark. However, airplane engines run around at a constant rpm all day so is advance really an issue? Plus you've got two plugs, so weak spark might not be a huge concern.

2. Reliability. Both devices have mechanical elements, so wear is a concern on both. I suspect that the pmag has less wear and therefore better longevity, but I have no direct expererience with either, so I'd love to hear from those that do. I realize the pmag is new technology with a limited track record, but if traditional mags are an ol' fashioned pain in the a$$ I'd like to know.

Thanks in advance to all.

Steve, I am interested in hearing the responses too, but one thing I just heard about the new firmware that the P-Mag has is...

You can install it in any direction and just press a button and tell it, CLICK... THAT is TDC.

DO this simulataneously and you are all set, timing-wise.

I thought that was pretty cool.

CJ

Steve,
I'm running an E-mag and a magneto with about 130 hours on 2 Emags - the factory gave replaced my early production example about 25 hours ago. I'm running a carb'd O-320 with a fixed pitch prop on a 6A. I've also got a P-mag in a box to replace the mag when I get around to it.

I believe an electronic ignition is of benefit when the rpm/manifold pressure pairing is not square, so either on take off or at high altitude. I got about a 50 to 75 rpm increase in static rpm. At high altitude I'm sure there is a definite performance benefit. A few months ago I was in Santa Fe and flew to the Dallas area. I climbed to 10.5K and set course and WOT, after a while I discovered my GPS did TAS calculations and figured that I was getting 168 to 170kt TAS (around 195 mph). Although I don't have good data from before the swap I never used to see speeds that high. So I believe I get better take off and climb performance and better speed at altitude. The engine runs more smoothly and I'm also able to lean much better, sometimes I can get the engine to run lean of peak (but not always, don't know why). I could never get any where close to lean of peak with 2 mags. Weak sparks are definitely an issue at start up where an electronic ignition really scores. No more cranking, cranking, cranking on cold, damp, days waiting for something to happen (although don't get many of those around here so would defer to someone with more experience from a damper climate).

Every 500 hours you will have to overhaul your Slick mag at a cost of ~$300 (OK, you don't have to in an exp airplane, but the engine will run much better if you do). I've also bought a new harness ($140) in the not too distant past, plugs cost around $20 each. With all the experimental electronic ignitions there are no SBs that I know of, the coils will last much longer as they are not installed inside a hot metal shell and spark only half as often. The plugs cost much less ($1.50 to $5.00 using car plugs) and the plug leads you make your self. The purchase price of an E-mag is a little more than a Slick, but the though life cost (parts cost & fuel savings) is lower.

That's always assuming the E-mag / other EI is as (un)reliable as a mag. I think wear is only a concern on a magneto. On an E-mag there is only one moving part, the timing disc driven by the gear, it runs in a bearing but is not mechanically in contact with anything else. The bearing has very little load on it. Although the P-mag has a generator on the drive shaft it is a brushless generator so again no mechanical wear. I don't know how many mechanical parts in a Slick mag, but many more than an E-mag, most rubbing on each other. The typical failure mode of electronic components is a start up failure, that's not to say they won't fail when running, but its much less likely. Although any failure is not good, a start up failure will allow you to discover the problem during the mag check and do something about it. The risk with any experimental EI is clearly greater than with a certified system as the reliability is something of an unknown (but I would not be surprised if it is better in the long run).

I've flown for around 1200 hours behind various ignition systems. I've suffered several failures (more than any other single system). Although none stopped the engine running, most prevented a further take-off.

EIs are not a complete panacea, some well respected people on this list have stated they would not fit an EI until some data that has yet to be published is available (such as the relationship of peak cylinder pressure to TDC). If I had an engine with 200 hours on it I would not rush out and buy E/P-mags (or any other EI). If the mags had done 550 hrs and the plugs were getting worn out the case for changing to EIs is more convincing, especially as you could sell the mags for a couple of hunded dollars each. If you fly low & slow the benefits you might get from an EI might not be as great as if you fly higher and faster.

Some of what I have written here is just my opinion that I cannot back up with data, so you'll have to make of it what you wish. I am very happy with my choice and would make the same decision again.

Yours, Pete