solid state ignition systems

Everyone,
I hadn't seen a thread on this or anything in the tech forums so here goes. I'm just about ready to order my engine and really like what I read about Lightspeed solid state ignitions as a replacement for mags. I want to go with dual systems (no mags). I understand how direct crank works and understand that Hall Effect is an electrical principle having to do with the flow of electrons. Can anyone address the pros and cons of direct crank versus Hall Effect as a choice of CDI system, or want to argue in favor of mags?
Thanks,
Bruce Sacks
RV9

Additional question

I'd like to add an additional question to Bruce's post:

Do any of the EI systems, as a dual EI setup, allow for communication between the boxes to ensure that they fire their sparks simultaneously? It just seems to me that it would be advantageous to do so. I may be wrong

Bruce and Alex,
The direct crank sensor is harder and more complicated to initially install then the hall effect sensor. Although once installed requires minimal maintenance and has no moving parts. The hall effect sensor is way easier to install and time but has periodic maintenance requirements. I am told the information derived from the direct crank sensor is more accurate then the information derived from the hall effect but honestly the difference in accuracy between the two must be very, very small.
As I understand it, and I could be wrong, the two systems of a dual system don?t talk to one another to coordinate the spark output from either; timing does this from the sensors. The two systems do look at each other and one or the other adjusts timing if the other should go off line for some reason.
We have installed many Lightspeed systems both dual and single, on our TMX engines and have virtually no negative feedback about the system from our customers.
Good Luck,
Mahlon
"The opinions and information provided in this and all of my posts are hopefully helpful to you. Please use the information provided responsibly and at you own risk."

For the sake of argument

When one is building it is easy to focus on ultimate performance but when that phase is done it seems to me the emphasis shifts to safety and reliability and a little compromise in performance is acceptable to get them. I read in Jack Cox's Sportsman Pilot (Winter 2005 - the current issue) some very interesting information about Lightspeed ignition systems in the article about Paul Lipps and his contribution to it (as well as his amazing propellers). I wanted maximum performance when I built our RV-6A but not at the expense of giving up the "stand alone keep the engine going if everything else fails" single mission reliability of mags (if it starts it will not be the cause of you not completing the mission). That is why I compromised and chose to use the LASAR system. Because Lycoming didn't time it propertly at the factory, it almost caused me to burn up my cowling but I got my own LASAR timing box from Van's, correctly set the timing, repaired the cowl (significant repair by the way) and since them everything seems fine. I am carying around a heavy box on the firewall of an airplane that is already the heaviest RV-6A I have ever read about (please don't ask). My cruise speeds are in the low to mid 170 knot range at 2450 rpm and a standard Hartzell constant speed prop (blended units were not available when I bought mine). Since speed is directly dependent on the blade angle and RPM of the engine (the plane can't fly faster than the prop would pull it through the air with 100% efficiency - I don't think a 74 inch pitch propeller cannot move the airplane 75 inches in one revolution) you have to have a constant speed prop or go to a higher pitch fixed prop to take advantage of a more efficient ignition system's ability to produce more power. Since I am getting very good speed with my constant speed prop I assume that the LASAR system is performing better than straight mags in power generation but I do not know that for a fact. Based on weight alone our airplane should be 1 to 2 knots slower than everyone else but the wing span is 18 inches longer so the baseline is not identical - and quite honestly I am not sensitive enough to detect 1 or 2 knots. If I were racing, always maintained my airplane in absolute peak condition and never asked it to carry me someplace when I wanted to go even if it was worn and tired, I am pretty sure I would go with the Lightspeed system but for my application the LASAR system which reverts to straight mag function in the event of electronic/electrical failure seems to be the better way to go. I have no good objective data that show the LASAR system is any better than straight mags. It is heavier than a straight mag system, it is more complex and once you shut it down on the ground you cannot restart it if the LASAR box fails, so a good argument can be made for the straight mag system's advantages for normal operations as well.

Bob Axsom
RV-6A, N710BJ

1 mag, 1 solid state...

I ordered my ECI Titan O-320 from Penn Yan Aero Service with one Slick Mag and one Light Speed Plasma III with the crank sensor. This combination gives the reliability of a magneto to get home if all else fails, and the improved performance and 15% better fuel economy reported by others who are already flying this combination. The LSE module gets its timing from the direct crank sensor.

A friend of mine has the same mag/solid state combo on his Superior O-320 with the same Hartzell constant speed prop ordered through Van's. We both have RV-9A airplanes. His is a tip-up canopy and mine is the slider. The canopy will not affect the speed of the airplane. He has been flying a few months, and I hope to be going to the airport in the next few weeks. I have flown with him one time since he completed his airplane and it is rock steady and easily exceeds 160 knots in cruise. And of course, when the power is pulled and that propeller pitch goes to minimum angle, it is like stepping on a brake pedal to get into a short field.

Jerry K. Thorne
East Ridge, TN
RV-9A N2PZ
(wheel pants & wiring)

1 EI, 1 mag

I'm also using 1 electronic ignition(Lightspeed-direct crank sensing) and 1 magneto. The EI runs the show because of the spark advance. The mag has no idea the EI is there and the mag is just brainlessly doing its job of throwing out a spark regardless of the fact that the fuel/air mixture has already been ignited(and the flame-front is probably already past the magneto-fired spark plug). Having that mag just plugging away as a backup is very comforting... especially when flying over rugged terrain.

The Lightspeed EI came already mounted on the Aero Sport Power engine and has worked flawlessly for 194 hrs.