I want to close out this thread by providing an update on the RCexl ignition and the stock "blue" ignition module, so that people don't get the wrong idea about these cheap Chinese modules and engines. The RCexl never ran right on my XYZ-26 with a 5-cell Nicd; it didn't give max power. I don't know why. The RCexl started to fail after a dozen or so flights; it become harder and harder to start the engine and tune it. The RCexl finally decided to quit sparking at all last week.

I replaced the RCexl with my stock "blue" module. The stock "blue" module has been running excellent; it produces very healthy looking sparks. The "blue" module kills my 72 FM receiver; however, my 72 PCM receiver appears to be unaffected by the noisy "blue" module.

In summary, here's my current (more importantly, good running) setup.

XYZ 26cc,
5-cell Nicd,
stock "blue" ignition module,
72 Mhz PCM receiver,
16x8 prop,
7200 RPM.

I'm taking this engine out of my Spitfire, and putting it into something more aerobatic. Any recommendations?