P Mags vs Lightspeed's Plasma II or Plasma III

Comparisons, comments, criticisms welcome. I'm trying to learn about these new-fangled EX ignition systems.

might consider EFII also. I own this ignition system on an IO-360, but haven't flown it yet .... hope to by spring. ( as in spring 2016 )

http://flyefii.com/

I chose the P-mag for simplicity and price. It seems to have a fewer number of components than the other systems as well as the ability to make it's own electricity. You can use a small 9 volt battery (wire this into your system if you wish) to get them started if your battery is dead. Once you make the small wiring harness, it is easier than installing and timing magnetos. I use it with automotive spark plugs which I chose primarily to see how they worked and secondarily price. $6 for an iridium auto plug vs What for an aircraft iridium plug times eight? You can get a complete set of auto plugs for the price of just one airplane plug. I'm happy with the choice.

I agree with Pete. The simplicity of the Pmag was a big draw. Keep it simple and light.

"Build for 90% of your flying" The hard part can be really, truly, honestly, coming to grips with what is your 90%.

Just my opinion

Bill

I have no idea what the 90% comment has to do with selecting an electronic ignition. I expect my ignition to work well 100% of the time.

The Plasma system looks small, light, and simple. The Hall Effect module is interesting. That's what fueled my question. They both use auto spark plugs. Cost is very similar. Hoping for a pirep.

Check out the RV Builders Forum. www.vansairforce.net Like this site, lots of good info to review.

Wow, lots of Light Speed and Pmag info. Now I have to add Electroair to my research as it has some good pireps, too. Thanks for the reference.

"I have no idea what the 90% comment has to do with selecting an electronic ignition."

It has EVERYTHING to do with it.

You are going to make hundreds of decisions as you build. If you do not have a clear goal, a specific game plan, a defined mission, through which every decision is filtered, you may very well be disappointed with the end product.

Just my opinion




​Bill

I work on a RV-6 that has dual light speed ignition system installed with the Hall effects... The only drawback I have to that system is it is battery dependent. It has to have 12 volts to the system or it quits.... So, the airplane has 2 independent electrical systems... That's 2 battery's, 2 alternators, 2 buss bars.... Etc.. Etc..

I have a customer that I am going to help install a single light speed ignition replacing the right mag with a Hall effect and leaving the Slick impulse mag foe reliability... That airplane is a Long EZ..

I like the idea of the P-mag better because it generates its own power... IMO only though..

Brian

Bill Rusk said:

"I have no idea what the 90% comment has to do with selecting an electronic ignition."

It has EVERYTHING to do with it.

You are going to make hundreds of decisions as you build. If you do not have a clear goal, a specific game plan, a defined mission, through which every decision is filtered, you may very well be disappointed with the end product.

Just my opinion




​Bill

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I can count my decisions on two hands. And I barely need those. For those who don't know, I'm awaiting a Back Country Revision 2 kit. It's been ordered with Keller flaps and the typical SQ slats riding on a TK-1 suspension. It's a big airplane so weight will likely be in the 1300# range even with a careful build. The biggest decision has been the engine and that's been driven by the inability to get a 409 from ECI. With the kind counsel of Bart Lalonde I've decided to use Superior's IO-400 angle valve/roller cam engine because it's big and powerful and the angle valve cylinders run cooler. I may opt to spend time in Dallas and build it myself. That remains to be seen. The next biggest decision will be the prop and whether to use a Catto fixed or Whirl Wind constant speed or ground adjustable. After that? What colors to paint it are about all that's undecided. It'll use a JPI EDM-740, Winter 2 1/4" airspeed and altimeter, an iPad mini, and more than likely an electric turn coordinator. Interior will be Kydex with Fine Line seating. What else is there? Hurry up and get it done, right? I refer to it as my personal aviation revitalization project. I'm looking forward to getting started.

stewart, While I have no experience with the Cato, I do with the Whirlwind ground adjustable. It is a great prop with the ability to choose the pitch for the situation. I have found that my Cub easily can out perform the prop. Unfortunately due to tubing location in the fuselage, I can not install a governor. I noticed that the IO-400 mounts the governor forward on the case. I highly recommend the constant speed version of the Whirlwind. This will give you full power for take off along with a respectable cruise. Rate of climb will increase 200-400 feet per minute and cruise will increase 12-15 mph.

Another advantage of the P-mags is that the shake of the four cylinder Lycomings during starting and stopping, is nonexistent.

It is what it is, and a certain SQ3 that many have seen in action demonstrates that the weight doesn't appear to hinder performance. Mine won't have a bunch of fluff but it will have the necessities. I'm looking forward to AKTahoe and Shooter finishing theirs so I have an idea of how to adjust W&B before I get too far into it. Fun stuff. Have fun with yours. Merry Christmas.

Stewart

I have 1400 hrs on my dual P-Mags and have had zero problems/issues. You will burn 1-11/2 gph LESS then slicks.
I like what you have speced out for the SQ.
Will you be keeping the 180 or selling?

Merry Christmas
Lou

I think I remember hearing the roller cam if you when a prop strike you have to replace the lifters? Or am I thinking of something different

FdxLou said:

Stewart

I have 1400 hrs on my dual P-Mags and have had zero problems/issues. You will burn 1-11/2 gph LESS then slicks.
I like what you have speced out for the SQ.
Will you be keeping the 180 or selling?

Merry Christmas
Lou

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Lou,

I didn't enjoy owning two airplanes the last time so the plan for this one is to spend way more than I can get out of it and that'll make it easier to say goodbye to the 180 (but I'm not in any hurry). Seriously, the Cessna is underutilized and I don't see that changing. I'll be more motivated to burn holes in the sky with an SQ and with the latest airframe revision it becomes a very useful airplane for my needs. I'm tired of thinking about medical reform so I figured I may as well go ahead and build a cool Cub while I'm young enough to enjoy it.

The reason I asked about the mags was that Superior offers Pmags and Light Speeds but clearly favors Pmags. I remember several failure Emag reports from about 10 years ago and wanted to hear that they're better now. I'll spec the engine with Pmags.

Merry Christmas,

Stewart

Stewart

Good plan! I'm struggling with a similar situation. I sold my '64 G model and bought a '54. Very light. 1570 SCALE weight. Flys like a SC. Hate to think of parting with my Smith. I love it and it hauls 1000#. The fact that my Dad and I built it makes it that much more difficult. Sure like the 150 mph tas on 10 gph.
Yes, the early P-mags were prone to heat shut downs. The 114 model fixed all that and they have been trouble free since. Make sure you have really hi flow blast tubes on them.

Lou

Nice. 470 in this one? Enjoy!

Yes

Cool! SB, are you going to document your build for others to follow or at least hit the highlights? Would be neat if both you and Crash did, I remember when he did his 180 cub and had a good thread on it.
I will also be watching Aktahoes build with the new airframe. Very interesting.

Probably not. I plan to keep a private log that I can share. Maybe even a blog. We'll see.

I see that you plan on using a Whirlwind c/s on the SQ2. Usually I see those on GlasStars or RV's. The big deal for skywagons is an MT, never heard of anyone installing a Whirlwind. Does MT make a prop suitable for a Cub, and if so how do people like it?

Pro Pilots has an STC for a CS MT on Cubs. Whirl Wind is EX only.

stewartb said:

Comparisons, comments, criticisms welcome. I'm trying to learn about these new-fangled EX ignition systems.

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I've worked on E-mag, Light Speed, and EFII ignition systems. In order of choice I would go with P-Mags first, Light Speed Second, EFII last.

Pmags win thanks to simplicity of installation and maintenance and their ability to self power once running. Simple installation and great support. On the down side, Emag has had some wear related maintenance issues with bearings. They recommend pulling the Pmags to send back to Emag for inspection annually. I do mine on at 200 hr intervals. Generally, they look them over and send them back. Quick turn around and $80 covers the inspection and any needed upgrades or repairs.

Light Speed makes a nice unit that you install and forget. Really nice unit. The only reason it's not #1 in my book is the dependence on the Electrical system.

EFII has it's strong points, like the processors can also run an aftermarket fuel injection system and unquestionably has the hottest spark of any ignition system. But it comes in last in my book for a number of reasons. Like LightSpeed, it depends on the electric system, so requires some kind of back up redundancy. It is also electrically very noisy. I've been helping an RV builder with his installation. He had to literally build a copper wire mesh Faraday cage around the coils to get the noise down to where the radio was usable. He still has ongoing noise issues, although not so severe, that seems to coincide with spark plug degradation. The EFII multispark system is great if you're racing and want to make sure you get the most out of every cycle of every cylinder, but it eats spark plugs and generates a ton of electrical noise. The electrical noise is a common problem with this system. The last issue I found with the EFII system is that it only rolls in 4° of advance above the normal sea level max power setting. With little advance, you don't get the opportunity to save nearly as much in economy cruise.

By comparison, the default timing curve for the Light Speed ignition will roll in up to an additional 16° of advance, while the Emag system provides two selectable timing curves that allow for either 9° or 14° additional advance. I put a selector swich on the panel for my Pmags and typically use the more conservative timing curve during the summer when CHTs and oil temps might be an issue, and the more aggressive timing curve when flying cross country and during cooler weather.

-Cub Builder

Great info. Thank you very much.

Very interesting info. I installed the EFII dual ignition system about a year ago. Absolutely no noise problem, it is the first I've heard of it. When researching the choices did not find anybody talking about that issue, maybe I missed it. You may have a unique problem case or bad units there not sure. Have not eaten any plugs yet, but then I paid $1.10 each for them on Amazon, I think I got lucky there because I see they a higher now. PMAG is a simpler install and more maintenance and has moving parts which you get away from with the other two choices. EFII is more complex to install especially on a retrofit situation, a new aircraft install would not be as much work. If you use his Buss Master system the battery management/power management issues are greatly minimized. With the EarthX batteries a second power source is really simple to install and use, and very light. I like the more current technology, stronger spark, no moving parts, fuel injection solution of the EFII system. Why would I want to remove Slick mags and install something that takes more maintenance than a Slick Mag? I almost went that way because of simplicity of install, so far I'm glad I didn't, but it was a lot of work to rewire under the panel. I noticed that when researching the choices that a fair number of the EFII installs were by RV folks removing the PMAGS and installing the EFII system. EFII system is a current automotive system, the ignition system failure rate is very low in the automotive world. I planned to install the injection part this winter but because of other circumstances that will be delayed a bit. I think all of these choices are clearly superior to the choices we had for so many years, do I put on Slick or Bendix Mags? Go with something without the more moving parts, it was such a pleasure to put cover plates over the mag openings on the back of the engine.:smile:

Couple of things I'd like to point out with any of these electronic ignition systems.

First, they all are dependent on electrical power. You need to do careful research into how each system functions in case of a total power failure. And how to start the engine if you have a stone dead battery. For instance, how low does the input voltage have to get before the system begins to fail? How fast does the engine need to turn to start if the system is 'self powered' or you are attempting to power it with a small battery. Can you hand prop it if necessary? Before you spend the money, you might want to attempt some of these emergency procedures on a similarly equipped engine. On the smaller aircraft, I'm not a fan of a total, dual electrical system. There are ways of wiring two batteries, one normal size and one smaller, to supply power to the ignition system, only, in case of an alternator failure. Another way is to make sure that your ships battery is big enough to supply power longer than your fuel supply will hold out. Plan your emergency procedures to dump all electrical loads except for ignition, in case of alternator failure. For this, a toggle switch can be used as 'emergency power': turn on the 'emergency power' switch and open the master relay and only the ignition system is powered.

Second, the noise issues. Not sure I buy the ignition system itself being the cause. Not every one that installs any certain model seems to have noise issues. And when it gets so bad that the comms are unusable, you need to dig in deep. Remember that many of these systems are installed with automotive spark plugs and wires. One of the reasons that aircraft plugs and wires are built as they are, is to reduce noise, Shielded connections and shrouded wires. You give that up with automotive components. But the correct automotive components SHOULD provide good noise reduction. Otherwise you couldn't use your AM radio (for those of us that still do). Technique and craftsmanship become super critical with these. You MUST use the correct wire to fab the plug leads. They have a small resistance built in, per foot of wire, that reduces the radiated noise. Plug wire without the built in resistance will work for the engine, but blast out lots of noise. Same with the spark plugs. There are plugs available with and without internal resistance, for the same reason. Lots of farm tractors out there changed spark plugs when someone mounted a radio and realized it wasn't usable. Taylorcraft used unshielded plugs/wires on some engines and they drown out comms as they taxi past other aircraft. So, if you choose one of these systems, make sure to use the exact plugs and wires that might be recommended. Fab the wires EXACTLY as instructed. Same with gapping/installing the plugs. Connect your power and ground wiring separate from your avionics wiring. Keep your antenna coaxes away from these systems.

Web

The dead-battery scenario is what pushed me towards P-mags. A simple 9v battery provides starting power and they are self-sustaining above some low rpm (800, I think?).

When my fixed-timing mags come out for service they'll get replaced with P-mags.

CamTom12 said:

The dead-battery scenario is what pushed me towards P-mags. A simple 9v battery provides starting power and they are self-sustaining above some low rpm (800, I think?).

When my fixed-timing mags come out for service they'll get replaced with P-mags.

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Have you started one like this? If you connect the 9 volt battery, can you hand prop the engine? Know anyone who's done it?

Web

If a 9v duracell will energize the mags? I can't imagine an aircraft battery being that dead. A normal battery will fail to start your engine in the mid 11v range. Even then it should have the juice to energize the mags for a hand prop. I guess if you left for a week with the master on it could be a problem but that's never happened to me. I have had weak batteries from temporary stupidity but it sounds like the Pmags should be okay with that. Probably the other brands, too. That should also mean that with a failed alternator you should have plenty of time to get down and parked before you drain down into the 9v range with a normal starting battery.

wireweinie said:

Have you started one like this? If you connect the 9 volt battery, can you hand prop the engine? Know anyone who's done it?

Web

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No, I haven't. Got my info from the emag website in the FAQ. I haven't bought any yet, waiting for another 350 hours when I pull my mags.

If anyone wants to buy me a set now I'll gladly test the theory! Haha!