Ignitions
 

2-Mags, 2-EI, or 1 of each?

Those who are engine ignition gurus, please help me understand what the pros and cons might be going with dual mags, dual electronic ignition syestems, or one of each.

My initial thoughts are that one of each may be the best compromise.

E-mags
 

Tom, The following link is interesting to me http://www.emagair.com/ They have a "P-Mag" which operates without a battery. This setup has me looking pretty hard at it. I like that it fits on the engine as a replacement for the mags.
George

Depends on when you plan to get airborne.

If you can wait for the E-MAG/P-MAG, I would. IF it works as advertised, and IF it stands up to the rigors of the engine compartment, then I think it's the way to go. For me, they aren't even shipping the 4-cylinder model yet and they don't make a 6-cylinder unit.

Now, I say IF, because I was on the leading edge of the LASAR ignition movement on my RV-6. Although they took real good care of me and eventually solved all my problems, it took awhile. I suspect that the E-MAG folks will have their share of bugs to work out too so you want to give this product time to mature in the field.

If you plan to fly this year, I'd go with the Lightspeed and one magneto. That eliminates the need for a second battery system which the E-MAG system won't need either. I think two electronic ignitions are a little dangerous without a backup electrical source. Besides, you get the same benefit from one system as you do with two.

Whatever you do, you want to design your system so that your engine stays running. While magnetos are really old and dated technology, they do have one advantage in that they don't require any electrical input to run. As long as the prop keeps spinning, you can find a place to land at your choosing. That's why I think the E-MAG/P-MAG combination offers some real promise over the existing technologies provided they don't encounter any unforseen engineering problems.

There 'ya go then.
Go with a Lightspeed on one side and mag on the other for now. Then later when the P-mags are tested and ready, replace the mag with the P-mag and get the best of both worlds.

Matt
RV7-A

Why would you go with a P-Mag and an E-Mag and not just two P-Mags? The answer may be obvious, but isn't the idea behind the P-mag the same benefits of the e-mag minus the battery requirement?

I lifted this from their website:

Q: When I run dual electronic ignitions, do I need two P-Mags, or can I run one E-MAG and one P-MAG?

A: One E-MAG and one P-MAG is what we consider "standard dual configuration", which should be quite adequate. However, given the small difference in price, many builders are opting for dual P-MAGs. Their reasoning is that one P-MAG is already "required" (in dual installations), so the only question is whether or not to invest $250 to make the second ignition self-powered. One E-MAG and one P-MAG should be fine, but it depends on how you make that value choice.

FWIW - I went for Emag and the standard impulse Slick mag. This will be my setup until I'm certain of the new technology. Then the Pmag will fill the Slick mag spot. For the price and benefits the Emag has outstanding value.

Kelly Patterson
PHX, AZ
RV-6A wiring
O-320 9.2:1 CR Emag

Don't mix and match EI brands
 

Actually you get the worst. With matched L&R ignition you will get better performance. IF you mix and match electronic ignition you are negating the advantage of having dual electronic ignition. There is no way two different EI brand ignitions will fire at the same time consistantly. Most advantage of EI is from the first one. The extra 1% of performance/efficency with the second EI, is only if it works together, at the (same time) with the other ignition. You might as well go one EI and a mag if you are not going to have matched EI. I asked E-mag/P-mag folks about going (1) LS and (1) P-mag, they did not recommend it, but to their credit they suggested going dual LS would better or Dual E/P-mag. They had nothing negative to say about LS. There are advantages to both. BTW Jeff Rose's ignition was out of production for a while but is now available again as electoair:

http://www.electroair.net/

Cheers George :D

A dumb question?
 

I'm not thinking about swapping my mags, but this discussion about combining electronic ignition with a mag made me wonder about something.

Isn't the whole point of electronic ignition to be able to vary the timing like a car does? Well how does that work if the EI plug is sparking well in advance of the mag-driven plug? Seems like you'd lose the performance advantage of dual plugs, because by the time the mag fires, the show's over. Wouldn't it be sort of like flying around all the time on one mag?

Just curious.

One EI or Two EI
 

Dear Just curious: Great question. One EI (w/ one mag) for discussion sake will give 4% more efficiency. The second EI will only give an additional 1-2%.

Well what is the single magneto doing with the one EI, one Mag set-up? Not much. At power above 70-75% the timing of the EI will be approx at the same 25 BTDC, however the EI with its much hotter and longer spark will overpower the Mag even if they fire together. At lower power setting the EI will start to advance, so by the time the relatively weak Mag fires late the show is over. The Mag is just going along for the ride. However even with this mismatch the single EI is so much better than dual Mags, it is a benefit. The question is if you want to pay for the 1-2% extra benefit the second EI gives.

For me it was a case of practicality. I had old Mags that needed to be overhauled. I was able to sell the mags and impulse couple and make some money. I kept the single no impulse mag gear for my EI hall effect trigger.

The down side of dual EI is the dependence of electrical power. There are work-around's such as a second battery. In fact they use so little power a healthy single ships battery should keep you in the air until you run out of gas. Some do use only a single battery. It is still an issue that has to be addressed that you do not with need to with Mags. The P-mag is a self powered EI, independent of the aircraft electrical system. Others go some elaborate means to prove DC power that seems to rival a B747.

My point is if you are going to get that extra 1-2% you think you are going to get with a second EI for more performance you need to match EI brands. If you are not going to add a matching second EI, which might not get much added benefit, my feeling is you might as well keep the magneto and save the money. As a side note Lycoming list a 2% differnce between single Mag and dual Mag operations.

The question of which brand is better, since they all cost the same?

LSE: From pure performance minded standpoint the LSE has the best features in my opinion. It is the only CDI (capacitor discharge) ignition and they have race minded features such as user adjustable cockpit advanced control and indication. CDI (multi spark) has a slight performance advantage over Induction Coil ignition, which is what the other systems use. As well you can display MAP and RPM with optional LCD displays. Also, the CDI can work on lower voltage. The down side may be the installation, box, wires, coils and dependence on aircraft electrical system. For most the racing features are not necessary. LSE offers crank trigger and all effect trigger (mounted in mag hole).

E-mag/P-mag: Is an induction coil system like the Electoair system. Works very well and has the best form/fit factor, which means self-contained units that mount on the engine like mags, without seperate coils and control box. Also with the self-powered version, the P-mag, you have less electrical redundancy issues (needs electrical power to start with). Although it does not have some of the LSE features it does have easier installation and the timing curve can be adjustable or customized by the factory, including reduced advanced for high compression engines. Timing advance above 70% power for more performance is always at the risk of detonation and engine damage. Therefore most are best served by the stock conservative timing advance, which works primarily in cruise. All the EI use a conservative stock advance curved to protect the engine.

Electroair: Also an induction ignition system. Jeff Rose sold the company I believe and is now being marketed again. The new design features separate controller, coils and hall effect trigger (fits in the mag hole). There are 1000's flying around. I would put it between the LSE and E/P-mag in performance and installation. Electro-air states you must have two batteries for dual EI configuration.

Performance and cost are all close. You have to look at features, installation and your needs. I will also say there is nothing wrong with Mags. However if you are starting from scratch, buying new you sould consider at least one EI.

Cheers George :D