Dual LSI Ignition

[Charles Davis]

I was talking with someone who rebuilds engines, and they were kind of down on electonic ignitions, and encouraged me to stick with Mags on my IO-320.

His statement was, "As manifold pressure decreases, you have to advance the timing, but no one can tell you by how much.

If you advance too much, your peak cylinder pressure will increase into the detonation zone."

He went on to describe some engines that he had torn down with electronic ignitions that had metal flaking and errosion of coatings on certain parts that he thought might be related to this problem.

Does anyone else have any experience with these issues?

[Matt]

Re the "Post subject: Dual LSI Ignition" subject.  Are you
asking about LSE ignition?  I haven't heard of LSI.

Matt-

[Anonymous]

Advancing the timing can be done safely so long as a complete understanding of the goings-on of timing and combustion is maintained.

For average/routine flight ops I personally think that electronic ignitions are simply sexy add-ons for people with free time and fat wallets.  Note I said routine operations.  I'd be willing to bet a soda that, in the aggregate, pilots using cockpit adjustable ignitions are likely to cause enough damage on this or that engine in the fleet such that the net savings of fuel costs is met with comparable increased maintenance costs.

For an oustanding dissertation on this subject please check out the three ignition articles on the CAFE foundations website:

http://www.cafefoundation.org/research.htm

[Waiter]

I'd be very interested in seeing these parts. I have a feeling there is a lot more to this story than is being presented.

There are folks who know a lot more about this than I, so I'm sure they will chime in if I get something wrong.

If the EI system is set up and operated in the auto mode, I doubt seriously this type of damage could occur as a result of the automatic timing changes made within the EI system.  

As stated by Guest in the previous post, I could easily envision damage if someone who didn't know what they were doing (someone like me) had retarded the ignition "WAY BACK" and constantly ran the engine like this, with a very lean mixture, Thinking they were saving fuel.

I can't see how this can happen to the every day user who doesn't have access to these controls, or leaves them in AUTO.  In Auto, the timing retards as a function of RPM and/or manifold pressure. I don't believe the Jeff Rose system ever goes past 40 BTDC, this is at 2700 RPM with sea level, full throttle.

I'm not familiar with the LSI system, but neither the Jeff Rose or the E-Mags allow manual adjustment operation.

I've been running a Jeff Rose EI since first flight.  My EZ has over 2600 hours on it. In that time, I've never had a failure of the EI.  In that same period, Ive replaced the left mag three times, and had one in flight failure.

HIGH ALTITUDE,  The Mag usually start misfiring between 15 and 18 thousand feet,  The mag I currently have won't fire at all above 18 - 20 thousand feet (I can turn it off and get no RPM change).

As part of my current round of upgrades, I'll be replacing my only remaining mag with an E-mag EI system.

Advantages of EI;

1) High altitude performance

2) timing automatically adjusts to operating parameters

3) Improved efficiency (It takes a couple horse power to run the mag, it take about 3 amps to run the EI)

4) Smooth idle - I idle at 350 - 400 RPM - SMOOTHLY ( I keep the idle speed up higher than it could be, because when it get to low, the impulse coupler on the mag starts clicking)

5) Improved reliability of the EI over the mag

6) maintenmance free, no points to adjust.

Check around and see if you can get more info on the failures mentioned by this mechanic.

Waiter

[easyrider]

I ran a Jef Rose Electroair system for 80hrs. I had no problems, I fitted a digital voltmeter on the advance output and the highest reading I had was 44deg.My other Mag, a Slick impulse was coming up to 500 hrs and about 14 years so I was looking to replace it with a second Jeff Rose. About that time I heard that Jeff was going out of business. I didn't want to mix the E.I.'s by going to an L.S.I. so I purchased an E-Mag, actually I bought a P-Mag which is self powered in case of electrical failure. This was one of the main reasons I went to E-Mag, with 2 E.I.'s you need a back up electrical system in case the main system fails.I ran the P-Mag for 8 hrs. and experienced a missfire problem which is being fixed by the E-Mag people.
I should be back flying this week so I'll keep the forum posted on performance.When I have 25 hrs on the P-Mag I intend fitting a second P-Mag to replace the Slick.
Easyrider

[Charles Davis]

I mean LSE (Lightspeed Engineering) ingition, not LSE.  Sorry.

Thanks for all the great info.  


What I take from this is to go with either a dual electonic (but forget the pilot adjustable timing) or with one electonic ignition and one mag.

[Anonymous]

I used one lSE ign. untill my mag died and then got another LSE.  I do not have cockpit adjustable iignition advance, aside from some bad ign wires and a couple of failed coils, it works great starts easy and is even easy to hand prop if the battery is too low to turn over the starter.
Juan

[afrogpilot]

I ran dual LSE ignition in my IO-320 powered Vari for over two years (250 hrs) and did not have a single ignition related problem.  As mentioned in previous posts, I had a real smooth low rpm idle.  I ran full throttle in flight most of the time.  No change during sea level or high altitude operations.  I loved my dual LSE ignition and will be putting it in my next project.

[Harry A]

Hi Charles,

I am of the "one of each" camp on this. I have been running an Electromotive solid state ignition system on the lower plugs for the last 11 years with no problems. I also have a Slick mag running the upper plugs.

While running two SSI would provide some added performance I don't think the small gain from the already efficient single, would outweigh the benefit of having two totally seperate and different systems in place for redundancy.

Also some of the systems I have heard of, running dual SSI, create dual battery and in some cases dual charging systems. to ensure redundancy. This can contribute to weight gain and increased complexity of systems and operation, while one of each provides that redundancy with no weight penalty.

As an aside I know of one Lancair owner who had a runaway alternator who fried most of the electronics in his panel along with his SSI part of that was a bad circuit design. Fortunately that happened while he was on the ground.

I have had an alternator failure and still completed a 3 hour flight home with no problem running radios and the SSI, monitoring battery voltage along the way.

I would also recommend to anyone considering electronic ignition to read all sections of the CAFE report on SSI as mentioned in this thread. This is must read info! I also believe the report supports the use of SSI and that it is not just an expensive add-on. Also I might be wrong but I don't believe most of the commercially available systems are "cockpit adjustable".

[Dan Patch]

There certainly are three camps on the electronic ignition (EI) issue - install one, two or none.  Folks can get pretty emotional about whatever camp they happen to occupy.  Regardless, put me firmly in Harry's "one of each" camp, for similar reasons and with a similar operational history.  My setup is the same as Harry's and has been installed for about as long.  The only difference is that I'm running EI on the top plugs, purely for geometric reasons (much better cowl clearance with auto plugs and wires).

1) There is little doubt that the variable timing available from an EI provides substantial performance advantages over running two, fixed-timing mags (e.g., better starting, smoother/lower idle, lower fuel consumption and more power at altitude).  

2) I believe that the additional performance that can be achieved by adding a second EI system exists, but is very small.  In my judgment it doesn't come close to justifying the "costs" of additional system complexity and reduced system redundancy offered by the one-mag/one EI setup.

In addition to Harry's Lancair example I'd add two more.  A dual EI equipped aircraft threw an alternator belt that destroyed the wiring to one of the timing sensors, and came within a whisker of getting the second sensor too (mangled its wires and stripped off the insulation, but it kept working - mostly).  

On a trip last year I was behind a group of EZ when one of the planes had to make a forced landing because his dual EIs both failed (he was REALLY LUCKY to make it to the only airport anywhere around - it was a very tense situation!!).  As I understand it, this was also an unanticipated single-point failure (i.e., vibration messing up the electronics) in what was thought to be a 'super-duper, redundant, can't fail, completely independent' installation.  

So the message that I get from this is there are some single-point failure modes that take more than two batteries, two switches and two alternators to address, and that they can be very hard to anticipate until they jump up and bite.  

As builders of experimental planes we are big kids who ultimately must decide how to balance performance, cost, and risk in whatever we build; so ultimately we're in charge.  My hope is that we will all take the time to gather enough information to make well informed judgments - which is what this forum is all about!  

Dan Patch
San Diego EZ Squadron Safety Officer

[easyrider]

The thing to remember when considering EI is you are replacing mechanical swiching devices with faily high maitenance and stoneage technology. The gain with one or two EI's is really irrevalent, what you are gaining is product with virtually no maintenance and superperior performance. E-Mag warranty their product for 3 years or 1000 hrs.
Easyrider

[Charles Davis]

Thanks for the lead on E-Mag.

Their P-Mag has a built in miniature alternator that takes over in case you have an electical failure.  

It seems you could safely run two of these and do away with the magneto backup.

It also installs in the conventional magneto space, which makes for a very clean installation.  

This looks like an awesome solution.

[Waiter]

Although I love the idea of the P-Mag, Make sure your aware of its operating limitations.

The P-Mag's internal power generation is only good down to 700 RPM. Some of our EZs will drop below 500 when the throttle is pulled back to idle. If you have an emergency, keep this in mind.

It may not be a bad idea to try a couple landings with 800-1000 RPM, just so you can experience it.

I chose the E-Mag for this reason. I will be installing a very small battery whose sole purpose in life is to supply power to the E-Mag when all else fails.  The circuit is simple and automatic, with the ability to manually tie the battery directly to the E-Mag if all else fails.   I have an electrical drawing on my web site

www.iflyez.com

Waiter

[Harry A]

Charles,

This e-mag p-mag product does look like a wonderful solution and it may turn out to be a cure-all item.

But!

Just be aware that this is a new product that has been out to the public for less than a year with not that many units and hours out in use. I also know that there have been some problems crop up. The company is responding positively to input so I am sure all will work out.

BTW check your clearances as I understand that the "P" unit is long enough to be a tight fit to the firewall. Although it does have an advantage in that part of it can be relocated off the unit to help this

Thanks for the lead on E-Mag.

Their P-Mag has a built in miniature alternator that takes over in case you have an electical failure.  

It seems you could safely run two of these and do away with the magneto backup.

It also installs in the conventional magneto space, which makes for a very clean installation.  

This looks like an awesome solution.

[easyrider]

The earlier versons of the "P" Mag were only good in emergency above 800 rpm. The latest version which I have generates voltage in emergency at 500 rpm.Talking to E-Mag this was achieved by closer tolerances on the induction generator.Unfortuneatly this gve a much higher voltage at high rpm and the controlling circuits were not designed to handle this higher output.The indications were missfiring and the electronic tach. going haywire.I had this problem that E-Mag. fixed and returned my unit.
I will be fitting it tomorrow so I'll keep the forum posted on performance.
I was concerned about the newness of the product but my Mags were due service/changing and I decided to give it a try, after all we are experimental flyers!.I do intend to put 25 hrs of local flying on the replacement before fitting a second P-Mag.
The E-Mag. people are very good to work with.
Easyrider