Ed, The reason the air gap plugs worked well was that they forced a high

secondary voltage. The

reason CDI works well in firing across "dirty" plugs it the very high

voltage they can produce.

The dc to dc converter used in the CDI usually steps the voltage up over

300 volts when the cap is

fired through the coil you get tremendous secondary voltage. Bill Jepson

And the rapid rise time has a lot to do with it.

Take care gentlemen, rapid rise time is the cause of 'cross firing'. I don't
know about the rotary but many a 6 cylinder motor has bit the dust when run
with a CDI.
Ed.
 The motorcycle plugs are NGK racing gold and iridium. B9EV leading B10EV
trailing.
Happy flying, Ian.

That was the old days Ian. Before silicone insulation :-)

Paul Lamar
 
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