As I've sat and read through dozens of postings dealing with ignitions
systems I remain fascinated at the creative thinking, inventiveness,
synergy, etc, of the various engine builders and builder wannabes.

But I also wonder why things must be so complicated.  I keep thinking
about the venerable chainsaw.  I've worn out a chainsaw or two, and I
have four running saws out in the shed right now. I could go out their
right now in the ice and snow and any of them will start easily with a
couple of pulls on a rope at about 100 rpm. They burn a relatively high
oil-content fuel, and yet I rarely need to even replace a spark-plug.
They idle easily, run air-cooled on 100F or -40F days, they run much of
their life at many thousand RPM, and I have never had to touch the
ignition system of any of them. I've heard of guys occasionally needing
to replace an ignition "module" on a chainsaw, but you can buy a
replacement module for about $10.

So it seems like we might be complicating things a bit.  Just what am I
missing?

Robin Berglund

They are probably capacitor discharge system similar to and out board
motor although I have never had one apart. As such the flywheel
with built in magnets is a bit hard to build for a home builder.
We are looking for something that uses cheap off the shelf parts
and simple or cheap enough to build by a home builder. The outboard
type is not quite there. Most chain saws are on cylinder so that
would not be suitable for a 2 rotor. Might work OK for a one rotor.
What does a new flywheel cost?

This photo system I have been working on shows the most promise
of meeting the needs of all the systems I have investigated so
far as it is dirt cheap. Other than the coils which are
now down to less than $30 each the electronic parts, what there
are of them, are less than $10. It does not make much sense
to buy an engine for only $3000 and spend $1000 or more on the fuel
and ignition system.

Paul Lamar