PMag Reliability

[paul330]

I am building a RV10 in the UK. Our airworthiness requirements normally require at least one conventional magneto - I know, it's mediaeval but there it goes

However, the LAA has approved at least one dual PMag installation on the grounds of equivalence. With the imminent (?) release of the P200 for 6 cylinder Lycoming, I intend to put forward a case for dual installation on my -10.

As far as I am aware, there has not been a single case of a double PMag failure leading to a forced landing. Confirmation, please?

[Brantel]

In the beginning, it was a wild ride for some.

The latest version has been pretty much bullet proof. I love mine!

[paul330]

I know there were some initial reliability issues involving over-heating, solved with the use of blast tubes. However "I love mine" doesn't really help with my case. I'm looking for hard facts

[nucleus]

I now have 104 trouble free hours on my early 113 models.

I had one lose it's timing at 96 hours. I think it was heat related. I flew all around the country right before it let loose and there were some extremely hot conditions - like 96 degrees at 11,000 feet.

Just turned 200 hours the other day.

After getting home that summer I figure out that the back of my plenum was flexing up when hot and spilling air - when I tied that down my already good CHT's dropped another 20 degrees, and I am certain that the blast tubes to the pmags have better flow as well.

Even though I had trouble with one of mine, I fly them with tremendous peace of mind.

I also LOVE how they perform - with some NGK EIX plugs they have a tremendously powerful spark - I can run 150 degrees lean of peak if I want without the engine missing.

I'm off to go flying!

[Toobuilder]

Originally Posted by nucleus

...I also LOVE how they perform - with some NGK EIX plugs they have a tremendously powerful spark - I can run 150 degrees lean of peak if I want without the engine missing....

Yep, both airplanes I fly are fully equipped with 113 Series units with no problems.

I also have started playing with "very" LOP operation and like you, -150 is no problem. Smooth, cool and sipping fuel... If you're not in a big hurry, it works out nice.

[DanH]

I'd like p-mags, but the need for blast tubes tells me they are marginal.

Old questions....how hot do they get with blast tubes, how hot without, and at what temperature does the failure rate spike upward?

[paul330]

Sorry guys, but you are missing the point. I know that PMags are the best thing since sliced bread, but I need some evidence to place before the authorities in UK. Has there been any documented case of a double failure leading to a forced landing?

[Bob Martin]

Originally Posted by DanH

I'd like p-mags, but the need for blast tubes tells me they are marginal.

Old questions....how hot do they get with blast tubes, how hot without, and at what temperature does the failure rate spike upward?

Dan, I like P-mags too, but haven't bought yet....BUT.....don't we install blast tubes to the mags as well.......my -6 has them.
and the alternator and the engine driven fuel pump???
Not sure the need for blast tubes is the, or a reason to not use them.

[Brantel]

Good luck finding hard facts in a room full of people with nothing but personal experiences.

If your looking for detailed statistics, you won't find em.....

[RV7ator]

Paul,

Emag probably could not tell you either, or won't. The dirty secret is the usual failure mode so utterly disrupts timing that the good ignition can't keep the engine running. If at altitude, simple to sort out and shut off the offending ignition, but once running, P-mags aren't known to fail. Of my three experiences in the bad old days, all failures were obvious at start or before liftoff, and I know of at least three other failures, one just yesterday, among friends, all occurring on the ground.

Mags fail, too, and impulse coupling bursts will ruin your engine, so my poison of choice remains P-mags, though I believe the failure rate is higher.

John Siebold