>From another list I monitor:
Maybe a 13B with one of tracy's ecms would benefit from a test run. BTW,
there are pictures of this cell in the latest AOPA mag.
Subject: PRISM Variable Ignition
Fm: George Braly 72311,556
There's an article in the Feb AOPA Pilot on the new PRISM fiber optic
variable timing ignition system. It was supposed to be in the March AOPA
issue, but they moved it back a month earlier. Marc Cook's left AOPA, for
another publication.
Don't have pricing, yet. That would still be a bit premature. However, I am
pretty sure that we can sell the electronic ignition system AND the
required full time supplemental alternator for a price that would be
competitive with the *real* cost of owning a pair of Bendix 1200 magnetos
for a TBO or so.
But the system has lots of advantages that we are still exploring how to
use to best advantage.
For example, it promises to allow us to move the compression ratios of all
of the equipped engines up about one to 1.5 full points (ie, 8.5:1 goes to
9.5 or 10:1) and STILL maintain the PEAK cylinder combustion pressures at
or below their present values. This would afford some rather substantial
performance and fuel economy gains at altitude.
It is remarkable. We were running the PRISM system today, on an IO-470. At
constant manifold pressure and RPM, and playing "foosball" with the mixture
knob, the timing would transparently adjust for the mixture burn time, and
move the timing from 18d spark advance all the way out to 35+ deg of spark
advance, and back again... damn near magic.
The engine test stand we built to use for the certification program with
the ignition system, is attracting some attention.
We already have two contracts to do an FAA 150 hour engine run and another
to do some fuel additive testing... the old "build it and they will come"
concept at work there, I think.
Very interesting stuff going on.
Regards, George
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