Dual P-MAG Reliability in 2017

[Timberwolf]

Originally Posted by Flyfish

I thought this was a thread about P-Mags.

You would think so, but the original question of dual p mag reliability seemed to be answered some time ago. This thread has actually thrown out a lot of information for 2 different ignition systems and lays out the benefits and draw backs of both. Almost. The pmags are much easier to install and can be a quick way to get into the EI game. However the CPI is a much more tuneable system from the get go, but it takes quite a bit more work to get installed initially. This thread has actually forced me to do more research on both systems. I do like the tunability with the CPI, but that big clunky controller is probably a deal killer for me. Wish they made a small 2 1/4" that did the same thing, along the lines of the EI commander. Or better yet if garmin would work with one of these companies and build a controller into the g3x system. I'm sure it looks cool in a race car but I feel like it looks too gimmicky for a plane. Either way, this has been an informational thread.

[rv6ejguy]

Originally Posted by Timberwolf

You would think so, but the original question of dual p mag reliability seemed to be answered some time ago. This thread has actually thrown out a lot of information for 2 different ignition systems and lays out the benefits and draw backs of both. Almost. The pmags are much easier to install and can be a quick way to get into the EI game. However the CPI is a much more tuneable system from the get go, but it takes quite a bit more work to get installed initially. This thread has actually forced me to do more research on both systems. I do like the tunability with the CPI, but that big clunky controller is probably a deal killer for me. Wish they made a small 2 1/4" that did the same thing, along the lines of the EI commander. Or better yet if garmin would work with one of these companies and build a controller into the g3x system. I'm sure it looks cool in a race car but I feel like it looks too gimmicky for a plane. Either way, this has been an informational thread.

Glad it's been informational. The CPI2 under development will have a much smaller footprint than the present setup and the green will be gone. Garmin won't play unless you can show a good case for benefits to them which is totally understandable. They have been approached and there will be provisions to communicate with other devices in the new unit to allow for future upgrades.

[drill_and_buck]

A few data points and opinions. I was an early adopter of dual P-mags and have been running them for 6 years and over 600 hours. I had a few teething issues in 2011 during my phase 1 testing that were promptly addressed by P-mag.

At about the 150 hour mark I swapped out my aircraft spark plugs for auto plugs and haven't looked back. The P-mags are dirt simple to time, easy to install and operate as advertised. Company service and support is way above the norm.

I get easy starts, smooth low RPM idle and can easily run my O-360 LOP. I'm not interested in experimenting with timing curves. I'm not saying there isn't a better system out there. It depends upon your mission. If I were to build again, I would make the same selection.

[Chkaharyer99]

Originally Posted by RhinoDrvr

I like the idea of the P-MAG?s the best, but have been unable to on find any data on reliability of the new, v40 firmware, latest version of the hardware P-MAG?s. I also think the P-MAG would be the most straightforward install given the LASAR setup I would be removing already has a Manifold Pressure Line etc.

What are your thoughts?

The real data regarding reliability of newer Pmags using v40 firmware is probably available and could be provided by the manufacture of the product. But based on past practice I seriously doubt they will share that data. Why? I am left to speculate.

Of all the Pmag related threads I've read here, I can't remember a single post where someone from Pmag has participated in the discussion. Maybe I've missed a few?

The question of reliability remains a mystery save for a small population of users who chose to share their experiences.

I will be replacing my Slicks soon and have gone through a simular information seeking exercise.

Enjoy your RV-8.

[Andrew Anunson]

Originally Posted by Captain Avgas

Now, if I'm reading this right EMAG have stated that they do not know why Loal's PMAG (V37) lost its timing and they have no reason to believe that V40 would have prevented the timing loss.

That is it... right there in the Captain Avgas quote. P-mags sometime loose timing (still making sparks, just at the wrong time). This greatly reduces engine power (or it quits).

To get back engine power the pilot has to know what to do... turn off the offending P-mag. Now... who among us wants to have to troubleshoot ignitions in flight under an engine out situation? Thats why we have 2 igintions... right? So one can keep us flying until we are ready to land.


With all other ignitions... if one quits or messes up or whatever, the other keeps you going to an airport. The pilot doesn't need to troubleshoot anything till on the ground. That is HUGE! If your ignition isn't automatically redundant like this, you can change it to be.

No other ignition gets off timing like that.

[Captain Avgas]

Originally Posted by WAM120RV

However that is why we have dual ignition systems, if one malfunctions you go to the other and land ASAP.

I have dual ignition systems so that if one malfunctions the other will automatically keep the engine running without a hiccup and without my intervention. The concept that one ignition failing might cause the engine to quit until the offending ignition is identified and switched off is absurd and extremely dangerous.

If an engine quits in flight an ignition check is way down the list of things to do. If it occurs at take-off or landing it is highly unlikely that the pilot will even have the opportunity to do an ignition check.

[KRviator]

Originally Posted by Andrew Anunson

To get back engine power the pilot has to know what to do... turn off the offending P-mag. Now... who among us wants to have to troubleshoot ignitions in flight under an engine out situation? Thats why we have 2 igintions... right? So one can keep us flying until we are ready to land.


With all other ignitions... if one quits or messes up or whatever, the other keeps you going to an airport. The pilot doesn't need to troubleshoot anything till on the ground. That is HUGE! If your ignition isn't automatically redundant like this, you can change it to be.

No other ignition gets off timing like that.

Originally Posted by @Captain Avgas@

I have dual ignition systems so that if one malfunctions the other will automatically keep the engine running without a hiccup and without my intervention. The concept that one ignition failing might cause the engine to quit until the offending ignition is identified and switched off is absurd and extremely dangerous.

So you've never had, nor heard of, a magneto losing its' timing in flight? A quick Google search shows it is far from rare with traditional magnetos indeed occurring 3 times in a 6-week SDR search, so PMag's are nothing new in this regard, yet everyone seems to be up in arms over it? I don't get it...

From a CAsA bulletin on the subject:

Engine roughness or internal vibration is also frequently linked to incorrect magneto-to-engine timing which can occur during operation, despite the timing being correct at installation.
There has been an increase in SDR reports to CASA describing advances in timing in between periodic inspection periods in 4300 and 6300 series slick magnetos.

Personally, I have dual ignitions (Dual PMag's as it happens) so that if one fails, however it happens, I can get to an airport. Cycling the magneto switch is one of the 'rough-running' or failure checklist actions for most spam-can's I've flown for precisely this reason...

[lr172]

Originally Posted by N941WR

The P-mags are great ignitions and way ahead of magnetos. Do they extract maximum performance out of an engine, no; however, neither does the ignition in your car or truck.

This is completely incorrect. Auto manufacturers have complete control of their ignition maps and spend 1000's of hours on the dyno optimizing fuel flow (i.e. mixture) and ignition timing. It is also done in harmony with other engine variables, such as temps. Granted, they also factor in reliability and emissions. However, they are highly optimized. They sell cars, in part, based upon HP claims. Trust me, they want as high of a number as they can get.

Timing makes a big impact on performance and even though many here don't want to hear it, it is variable based on many factors, the most profound being mixture. I can't imagine having an EI that cannot be adjusted based upon my mixture setting (ROP vs LOP). It would be like not having a mixture control and just feeding full rich through the flight regime.

I do agree with Bill that if you favor simplicity over performance, the Pmag is a good upgrade option over the mag. However, I would still buy the CPI for cost and reliability.

Just to give one example of the benefits of flexibility, I solved my FI hot idle problem by bumping my idle timing to 35.

Larry

[Av8rRob]

Ross, with your upcoming CPI2, besides the actual unit you are now designing, what sort of cockpit switches do you recommend for a dual cpi setup? I?m guessing two independent on-off switches for each cpi.

[rv6ejguy]

Originally Posted by Av8rRob

Ross, with your upcoming CPI2, besides the actual unit you are now designing, what sort of cockpit switches do you recommend for a dual cpi setup? I?m guessing two independent on-off switches for each cpi.

We're trying to eliminate as many external switches on the CPI2 as possible. I can't say at this point until software and testing is closer to completion. That's probably at least a month away.