I'm interested in following your progress in replacing your Lasar with Plasma. As you know, I also have the Lasar. Please let us know (I'm sure that you will) what is involved in the conversion and the results of the new ignition.

Bill, Matt, Et Al:

 

Thanks to the several people that are interested it this process.  Let me set a basis for the series of notes on this project.

 

1. I am making the conversion on a wee Lancair equipped with a Lycoming IO 320 (Titan Cermi-Nil cylinders and 9:1 pistons) that went from Slick mags to the LASAR system and now is moving to the Lightspeed Plasma III electronic system.  The conversion is a freaking wiring nightmare along with parts placement problems - all related to MY airplane.  Some assembly required and your results may differ.

 

2.  If you are building, have not yet finalized firewall forward issues and are considering this particular electronic ignition, planning can make its installation a snap.  Read this exercise for its cogitation value only.

 

3.  If you don't think electronic ignitions are meaningful, don't bother to comment - you cannot change my mind. 

 

4. Lightspeed information is available at:

 

 

5.  P-Mags ( http://www.emagair.com/ ) were considered and discarded because there is not enough usage information (especially with higher compression engines) and the timing is a "secret", just like LASAR.

 

 

Alright, now for some of the steps and decisions made to further the installation:

 

1. Removing the LASAR involved taking off the vacuum pump for access, removing the "mags", deleting the harness, de-labeling the panel switch and light and pulling the RPM sensor wire back inside the cockpit for later connection to the LSE unit. 

 

2. I obtained both the mag-replacement(A) and flywheel-mount(B) timing devices and, although I think the B system is more accurate, I have gone with the A system because I may not have the proper bosses for mounting the sensor plate and I don't care to futz with pulling the prop, etc.  However, option B could be better - especially if LSE places the magnets on the flywheel ($50 charge) although with a high compression engine the magnets would be permanently mounted at 40 degrees instead of 45 degrees BTDC.

 

3. I considered the following  placement of the LSE controllers:

a. Firewall forward - rejected because of heat concerns and space even though component access would be easy. Power and display wire would have to be routed through the firewall.

b. Under the seats - rejected because there just wasn't enough clearance, especially for the wires.

c. Behind the seats - Uhhh, to far back plus I would have to move my oxygen tank.

d. On the aft side of the firewall - rejected since so much other stuff is mounted there.  Plus, there is no room between the adjustable rudder pedals (generally positioned all the way forward) and the firewall.

e.  Passenger foot well - accepted because one was placed vertically along the fuselage wall behind the interior and the other was horizontally mounted just beneath the header tank with brackets attached to the firewall.  This was a benefit because the unit interconnect harness did not have to be completely remade.  The horizontal loftier placement does not seem to interfere with any shoe size under 12.  The vertical placement does not interfere with the passenger's right foot because the rudder cable keeps the foot away from the sidewall.  The major drawback - the canopy/header-tank have to be removed for component access.  Oh well.  Additionally, I had to relocate the panel flood power supply and the AOA controller box (previously located behind the side wall interior) - more re-wiring. 

 

The second unit can be seen peeking out from behind the sidewall interior at the top of the pix.  Once the boxes were located, other installation item could be accomplished.

 

4. Firewall penetrations:

a. MAP is connected to primer port (cylinder) using old LASAR fitting with a restrictor and Earl's super hose thru a -4 preexisting bulkhead fitting.  Once inside, there is a reducer to 1/8 inch tubing, then a tee and finally connecting to both units.

b. The RG-400 unit outputs to the coils (seen above - left center) pass thru a 4-hole homemade aluminum "bushing".

c. The timing sensor wires (6-each) pass thru the firewall via a 16-pin plug and bulkhead socket connector.

 

Hook-up and POWER logic:

 

Left = Loft = top = display = backup power = primary.  In other words, the top plugs are controlled by the top unit.  The sensor, breaker and switches for this unit are on the left or labeled "Left".  The 4.5 AH backup battery is routed to this unit. Hereafter to be referred to as "L".

 

Right = Rear = bottom = secondaRy.  The bottom plugs are controlled by this unit which is located below and to the rear of the primary.  The sensor, breaker and switches for this unit are on the right or labeled "Right", hereinafter to be referred to as "R".

 

So.....

 

1.  R is powered from the Essential Bus (ES) and can receive power even if a problem on the main bus required the master switch to be off.  The ES can be switched directly to the main battery but in normal operation draws power thru an isolation diode (Perhelion - Eric Jones - about a .2 VDC drop).  The Key switch must be  on R or Both.

 

2.  L is powered from the Main Bus (after the master relay) or directly from the backup battery (BB).  BB is isolated from back feeding the Main Bus by a diode, but does receive charging from the alternator. A panel switch directly hooks this battery into the L unit.  The key switch must be on L or Both.  Engine starts may be facilitated by switching on the backup battery since its power is unaffected by starting motor draw - I will test this.

 

3.  The key switch jumper to ground out one of the mags was removed for LASAR operation and should not be used for LSE either.  A builder should consider just using separate switches.

 

4. The appropriate grounds were routed to the BB and directly back to the main battery minus.  The BB is stuffed into the right wing leading edge stub wing section behind the interior.

 

5. A document was obtained from Vision Microsystems that describes the possible circuit for hooking up the 10VDC, .3 MS duration digital RPM signal to the VM computer (involves a resister and diode).  I probably erred in that I chose the feed solely from the L unit while the R unit could be the only one operating (and the VM instrumentation would still be powered).  One could install a switch to select which unit provides the VM RPM data.  Note that there are 2 pulses per revolution - just like the LASAR so nothing more had to be done to the VM computer (change made when LASAR installed).

 

The Panel:

 

 

The ADF display was replaced with a filler and most of the LSE stuff was placed on that filler.

 

a. L and R pullable 5A circuit breakers.

b. Selector (between the breakers) has the following positions:

  i. RPM

  ii. MAP

  iii. L (primary) timing.

  iv. R (secondary) timing.

c. Simpson display.

d. L and R pots wired to a 9-pin D-Sub for possible future connection to units for timing "adjustments".

 

To the left of the circuit breakers are:

a. Protected sw to power the L unit from the BB.  Down is for normal operation (L powered from main bus) and Up is L powered by BB.  Shut down checklist is to make sure all switches are down (OFF).

b. 10A pullable breaker for main bus feed.

c. Below is a selector switch to feed voltage to VM voltmeter display:

  i. Main Bus voltage.

  ii. Essential Bus voltage (also seen by R unit).

  iii. L unit power voltage tapped after sw and is either Main Bus voltage (reduced by isolation diode) or BB voltage, depending on switch position. Post start checklist item could be to check BB voltage.

 

I am working on the panel labels and firewall forward for a future e-mail.