If you want the simplest and probably the
most reliable ignition system get a two cycle
two cylinder small outboard ignition system.

Fires the same number of times and 180 degrees
apart just like a 2 rotor.

As close as you will come to a A/C magneto.

http://www.iboats.com/

http://www.iboats.com/Johnson-Stators/dm/view_id.271367

http://www.cdielectronics.com/
Down load the complete catalog.

Some of these stators are as low as $20 used.

The high voltage coils supply 300 volts for a
simple CD system and the other coils supply enough
12 volt current for an EFI system. No belts. If the main
electrical system or alternator fails the engine
still runs.

This stuff is mass produced in the millions and extremely
reliable.

Paul Lamar

Some interesting stuff in that catalog. Some of us wouldn't
know exactly what would comprise a complete system, as it
looks like they are all parts of an upgrade for certain motors.
Did you notice the EFI and ECU units in the catalog? They
also note that these can be reprogrammed for "racing purposes".
Would this be suitable for our purposes? Of course I don't
think it would be a good idea to mention aircraft. One cold
say I'm making a marine rotary conversion.
C. Smith


Good idea Craig. A racing rotary boat motor.

All you need is a source of 300 volts, a 1 ufd 300 volt cap and
a switch of some sort. An FET works fine and they are easy
to use. Way back about 30 years ago we discovered that a 50 cent
CMOS CD4050 or a CD4049 chip makes a great FET driver
if most of the six gates in the chip are connected in parallel.
Since that times 1000's of FET gate drivers have been  designed
and built selling for as much as $6 each and so far I have
not found one that works better than a CD4050.
Many of them require a regulated supply which lowers efficiency
and cost more money and parts.

I set up this simple CD circuit on the bench in half an hour
and it works great except for the $150 300 volt supply.
In theory it is 30 watts which should be enough.
Unfortunately the high buck PS does not like to work with CD
systems. It shuts down for several milli seconds right after
I fire the cap. It sees the short. That means the RPM is limited.
The heat sink is essential.

The FET is a IRF740.

I am rapidly discovering it is all about the 300 volt
power supply. You need a robust power supply that does
not crap out when it is shorted to ground and that is where
the charging coil in the outboard motor comes into play.

Nothing could be simpler than a large magnet passing
a coil to rapidly charge the 1 mfd cap.

Paul Lamar