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[LML] One mag, One electronic ignition
Hey Doug,
you went and changed the subject
line.....bad news for those of us that sort by subject. anyway, my
$.02
- more power: in theory you can set up a mag
engine to get the same power in one config. In other words,
if the main thing you care about is cruise, you could set your spark timing to
be just right for your favorite mixture and your favorite rpm.
- engine damage. lacking variable timing, all
you have is mixture to protect your engine from harm. With fixed timing
it's clear what to do (e.g. if you take APS). With some unknown timing
curve in an electronic ignition box, I don't know what to do. I asked
Klaus what his timing curve was really and he just blew me off.
Lacking that information, I wasn't willing to have his box in my
airplane.
- open loop control systems. As far as
I know, all electronic ignition systems that are for sale are open
loop. ....meaning they determine timing based on control inputs but
don't actually have any sensors in the cylinder to determine what is
happening. PRISM's approach is radically different in that it
measures the angle of peak pressure and tries to keep it in a very narrow range
no matter what you do to the engine controls. As a result, you can
run right at peak, ROP, LOP, whatever you want. ...and this has obvious
advantages both in terms of power and engine longevity.
Unfortunately PRISM isn't for sale at this point.
- one mag and one electronic. Seems
plausible but you lose timing control if you leave the mag on.
If I were going to do this I would want to run most of the time with the mag off
I think.....and that would mean different timing curves. I
don't know if any of the electronic setups deal with that properly or
not.
- backup power. GAMI does have a
supplenator for sale. It's a self-exciting replacement for your backup
alternator with automatic load shedding. I'm also intrigued with the
e-mag idea.
conclusion: I decided to stick with 2
mags until I see a) a seriously bullet proof backup power solution.
b) a closed loop ignition system or an open loop system that is clearly
documented and backed up by test stand analysis. For what I
care about I can get most of what I want by cruising LOP and just using a lot of
gas in max power configurations. A good electronic system would
allow cruising AT PEAK without damaging the engine and that would mean some
incremental power.
Colyn
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