Information on P-mags
 

Folks,

Anyone could give me some information and data that help me to decide to use either

-Standard magnetos; or...
-Light Speed electronic ignition systems; or...
-PMag ignition systems;

What should be better (less fuel consumption or more horse power )

Are them all reliable and dependable ?

Any experiences or readings to help me decide? (I need more horse power wiht same or less fuel consumption but I want safe systems)

I run a Lightspeed on one side and P mag on the other. I like the safety of the built in alternator on at least one.
The down side is that my cyls. have been running hotter than with the Slick on one side. Advanced timing is to blame I suspect.
Plane sure starts well and runs strong ... with the hot sparks.

Here is my experience over 425 hrs, I've had all 3 systems that you mentioned...

I started out with an LSE (direct crank sensor) and a slick mag at first flight, 3 years ago this week.

The slick mag was not new, but had been tested, inspected, and yellow tagged by a reputable shop. It failed after 14 hours and was replaced by a P-Mag. I also liked the self-powered aspect of the P-Mag and I require at least one ignition not reliant on ships power.

The LSE has NEVER had an issue of any kind, its been totally rock solid.

The P-Mag has failed 3 times requiring parts or replacement, each failure has unfortunately occurred hundreds of miles from home. Right now I plan to stick with the P-Mag. I have had no issues with temperatures and no timing anomalies.

Having at least one EI will significantly improve fuel economy, having two EIs provides little added benefit from a fuel economy or power perspective. I don't think it matters much whose EI you have, any of them will provide the benefit of easier starting, smooth low idle, better fuel economy, and slightly more power as compared to fixed-timing magnetos.

In my opinion, any of the current EI's would be an improvement over traditional mags. Personally I like the formfactor of the P-mags. No additional coils or brain boxes to install. Pmags are more of a component replacement situation.

The earlier E-mags had some issues but I have not seen any problems posted here for a long time now. The newer Pmag 114 are the most recent version.

Slightly higher CHT and lower EGT can be expected with any EI system over mags.

Better fuel economy (in cruise configuration), easier starting, smoother idle, less ignition maintenance with EI.

Pmag factory support is top notch.

Bevan

4th option
 

Marton, I have the same doubts as you, plus one. Have you considered EFII?

http://www.flyefii.com/EFII_desc.htm

You are asking a series of questions that are difficult to answer without telling us how you want to use the machine. In my opinion all three options you list are well proven, safe and reliable as long as properly installed and maintained.

• Only mags stand any chance of surviving a lightning strike. They are also easily repaired in remote locations (when you don't live in the US this can be a consideration).
• The Lightspeed is redundant when installed on both sides, but relies on ship's power. Klaus has certified a version of it on the Cabri G2 helicopter (EASA) - supplemented by a mag on the other side. They need to be installed properly, locating coils in the wrong place and exposing the box to excessive vibration/heat has caused issues for some builders.
• P-mags will run on their own, without ship's power and are fully redundant. They are self contained and easy to install.
• EFII is a little cheaper than the others, but not redundant without the duel ECU option. Adding two ECUs and their electrical box significantly increases the complexity (and cost).

Performance and economy wise the electronic ignitions are the better option. They start more easily, produce more power and use less fuel. There is no free lunch - your engine may well get hotter due to the advance and need more cooling.

I don't think there has been a conclusive bake off of all of them, so no one can really tell you which system produces the most power. I really doubt there is a lot of difference between the electronic options.

On a four cylinder I'd buy duel P-Mags (and that is what I have been running for the last 500 hours). I like the ease of installation and redundancy. They have been bullet proof and the company support is outstanding if you need them.

If you really want performance, make sure you install a constant speed prop. That will make a lot more difference than a few extra HP from electronic ignition.

Very informative, thanks a LOT !

On my injected 180hp 10:1 360; I started with 2 Bendix mags, ran fine but not the best for starting when hot. Then I added an ElectroAir to the right and left the Bendix on the left. Huge difference in performance, smoother running and started hot or cold easy. Used this setup for many years, never a hiccup. Then I went to 2 P-mags (114) with an EI Commander. The engine ran even smoother with the L/R timing the same, started just as easy hot or cold, lost some performance, CHT's a bit higher... But I had nothing but problems with both P-mags over and over again. After months of screwing around with them, swapping parts myself, I finally got them stable. They've both been working fine since but you can bet I keep my eye on the EI Commander.

What is the standard timing for your engine and do you have the jumper installed in your P-mag?

Don't forget the Electroair. It is based on an inductive-discharge automotive system that is manufactured in the thousands per year. They also have a certified version. I prefer inductive-discharge systems for arcane technical reasons.

Having experienced an electronic ignition failure in flight (installation error), I would highly recommend a conventional mag as a back-up. Having two electronic systems does not provide the right redundancy... Certainly not two identical systems.

I also prefer electronic ignition systems where all of the electronics is on the cold side of the firewall. High temperature, temperature cycling and vibration reduce the reliability of electronic components.

One factor often ignored, but should not be, is the effect of ionizing radiation caused by cosmic rays or gamma ray bursts.... Which increase with altitude. I don't think any of the extant electronic ignitions are sensitive to these due to the fundamental design, but as we become more dependent on deep submicron devices and intolerant programming, it will become a factor.

In the computing industry, we normally detect errors and hault (e.g.blue screen). In the telecom and datacom industry, we just flag the error and keep on operating. This requires self-initializing devices with no hidden lock-up states.

Aerospace is a lot like telecom... High reliability, fault tolerant and field serviceable.

At least one EFIS vendor I know has a telecom pedigree.... Don't know about the ignition vendors.

... And that's why your backup should be a Magneto.