snip...


   For a magneto, perhaps a motorcycle-type setup could be fashioned,
   using
   generating coils mounted around the flywheel. The coils are excited by
   magnets permanently mounted in the flywheel. You could have a separate
   set of coils for each spark plug, so you have the equivalent of dual
   magnetos.

   The Rotax magneto system is based on this architecture and works very
   reliably. A third set of coils goes to a rectifier and provides charging
   for the battery. So you don't even need a belt-driven alternator if
   your
   power requirements are modest. If you need more power, just add an
   alternator.

   I think Revmaster also uses something like this. And some VW and Corvair
   powered airplane builders use a similar setup with parts from a Harley
   dynamo similarly mounted to the crankshaft.

   With this magneto setup you will almost always have spark as long as
   your engine is turning. You can't say that about an alternator system,
   even if you have dual buses and alternators -- there are still possible
   failure modes, with wiring, belts, control boxes, etc.



   Regards,

   Gordon.



   This distributorless coil ignitions sounds very cleaver, but I wonder if
   there is a way to get such a system to work on a rotary engine.. In a
   conventional 4 stroke engine, you get wasted spark, and off the top of
   my head, on a 2 stroke, you use every spark generated by such a system.
   I have a sense that the rotary timing needs to be different - not synced
   with the e-shaft, but with each rotor.

   We have discussed the flywheel/driveplate integrated alternator in the
   past, and I still think it's the way to go...


   Matt-

   It syncs with the e-shaft no problem Matt.
   One firing event every 180 degrees. One event for each rotor.
   Two sparks per event. Four sparks total.
   If the coils had enough turns to generate
   300 volts you could have four capacitor discharge systems.
   You would need four external coils and four FET's to fire
   the caps.

   Paul Lamar ...No rotor no motor.

   Paul,

   What you described is how the Ducati capacitor-discharge ignition
   works on a Rotax. This is very similar to what is used on a lot of
   motorcycles and lots of off-the shelf parts could be used.

   The only thing I'm wondering is how to retard the advance during
   engine start? I'm assuming the Rotax does this, but not sure how.

   Regards,

   Gordon.


True retarding the ignition helps start but a lot of engines
don't.

Paul Lamar ...No rotor no motor.

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