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PMag Reliability

P

paul330

Well Known Member
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 :mad:

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

The latest version has been pretty much bullet proof. I love mine!
 
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 ;)
 
104 trouble free hours on 113 models

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!
 
nucleus said:
...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....
Click to expand...

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.
 
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?
 
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?
 
Blast Tubes

DanH said:
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?
Click to expand...

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.
 
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.....
 
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
 
Bob Martin said:
.....don't we install blast tubes to the mags as well....and the alternator and the engine driven fuel pump???
Click to expand...

Obviously all the reasons have to do with temperature. In the case of mags, alternators and fuel pumps, can anyone here tell us a measured before (without blast tube) and after (with blast tube) temperature for any of them?

While contemplating that bit of thread drift, let's return to Paul's question. He needs data to convince UK authorities of P-mag reliability.

I contend blast tubes don't actually lower component temperature all that much, so I consider the P-mag requirement for a blast tube to be an indication that the electronics are temperature-marginal. I ask for actual measured temperatures, with which anyone is quite welcome to prove me wrong. Heck, I'd be happy to be wrong.
 
There is a guy that had a forced landing.. Now was it forced or was it precautionary I can't remember. But he did document the event here on VAF.

The early failure mode is one of the Pmags would lose its timing and the cyl head and oil temps would rapidly go out of control dure to pre-igniton.

Now IF you shut down the offending Pmag normal service is restored, but thats a big "IF".

The guy I'm tolking about either chose to or was forced to land on a road.

Now this was a few years back, the modern generation I don't believe have had any problems.

Frank
 
I know that PMags suffered early in their development, mainly due to overheating. I also believe that later upgrades and the use of blast tubes seem to have eliminated this failure mode. I also know that Pmags will fail from time to time just as traditional mags will. Hard statistics are going to be difficult to lay my hands on but my gut feeling is that the mature PMag has to be more reliable than the magneto.

Most importantly, I need to be able to tell the LAA that in the last 4 years or so, there has been no dual failure. I believe that to be the case as I am sure I would have heard on this forum. Of course, it is difficult to prove a negative but at least I can say I have researched the matter and found no case.

Thanks for your interest and help.
 
I know that PMags suffered early in their development, mainly due to overheating.
Click to expand...

Pmags suffered from more than temperature issues, most of which were commented on in this forum. Do some searching. :)

I remember issues with internal magnet and/or sensor mounting coming loose. There was a big stink about the mechanical design of the magnet (or sensor) mounting at one point. I remember issues with SW crashes (causing timing maladies) that were probably caused by temperature. I remember issues with the "blow in the tube" timing setting being lost.

All these issues seem to have finally been addressed competently. :)

But if you want hard statistics, you have two sources. NTSB and Emagair themselves. Of those two, probably only Emagair could tell you how many have failed vs how many have been sold over the last x years. I don't think that how many units they have produced is required to be public knowledge.

Best Luck.
 
Actual double failures?..Probably none..But if you loose the timing one (and don't shtdown the offending Pmag) it could and we think did cause a forced landing.

Now of course now that anyone who flys 2 Pmags will be much more alert and ready to try shutting down one of them to isolate the fault.

I am quite comfortable flying a Pmag and Emag combo.

Frank
 
emag

We had an Emag failure that upset the timing and the engine only just ran, did not keep us in the air. Luckily we were over an airport and put it down.
It is extremely important that if you are running Pmags or Emags that you have to be aware of this issue so if presented with a very rough engine to try switching of one Pmag at a time. This should be part of the emergency checks if running Pmags. It is for us now.
We were not aware of the failure mode until it happened and it was only on the ground that we thought about it.

Rob
 
EIC

I installed an EIC, so I can monitor the timing and harness. It will alert you if the timing is off more than six degrees. On the ground, you can also check the prop position for each PMag, therefore allowing you to check the index without removing the cowling. Maybe having a monitor would help your certification.
 
Back to the question.

The problem is there is not a P-mag for a six cylinder engine just yet.

Emag has their six cylinder ignition in testing but it is anyone's guess as to when they are going to release it.

The architecture of the six cylinder ignition is significantly different than the 113 and 114?s. Thus, our experience with the current units does not translate to the RV-10.
 
rv8or said:
We had an Emag failure that upset the timing and the engine only just ran, did not keep us in the air. Luckily we were over an airport and put it down.
It is extremely important that if you are running Pmags or Emags that you have to be aware of this issue so if presented with a very rough engine to try switching of one Pmag at a time. This should be part of the emergency checks if running Pmags. It is for us now.
We were not aware of the failure mode until it happened and it was only on the ground that we thought about it.

Rob
Click to expand...

Rob is correct. If you are flying and experience a suspected ignition issue, turn one ignition off and if the engine runs rough, turn it off immediately and turn on the other ignition.

You have a 50/50 chance of turning off the offending ignition. If you pick the bad ignition, the engine will settle down immediately. If you shut down the good ignition, it will run really really rough. In that case, turn off the ignition and turn back on the first ignition you turned off.

For those who haven't lived through the teething problems of the early P-mags, if you have the 113 series (they do not have cooling fins on the neck) and you don't know if they have been back for both the software and magnet upgrades, stop flying immediately!

The only fix is to send them back to Emag for the upgrades. We have had EICommander clients who continued to fly the 113's and knowingly ignored the service bulletins because the ignitions were working fine, right up until they didn't work fine. Good news for us because that pushed them to purchase and install an EICommander.
 
sorry to contibute to the thread drift but...

...isn't a mag check standard operating procedure for ANY mags in the case of rough running engine? I think the only issue is if you have time to do it, but it is not peculiar to EMAG/PMAG. I had to do this with a LASAR failure and it was unequivocal, but I had time and a conveniently located runway that I had just departed from:eek: BTW, that event was what lead me to get dual PMags:D
 
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