I'm the guy that had a bad plug. Absolutly nothing to do with the engine itself. The element broke where it is welded to the plug side body, but maintained contact allowing the engine to start and no "bad plug" indication. However, after startup, the element vibrated, metal on metal, resulting in massive RF interference (keep in mind that no matter how well balanced, these engines still vibrate. At 35,000 rpm, even the tiniest vibration in that situation is not good.) Fortunatly, I caught the problem on the ground.

Having said that, and with the knowledge that some may see some bias in my comments (see sig.) I put just over 16 hours of run time over about 65 flights this past summer on my AD Phoenix with the Behotec J66HP. That bad plug was the only problem I had that was not the result of something I did (like forgetting to open the fuel valve.) I will be returning the engine to Peter this winter for inspection and installation of the kero start option.

Although the manual recommends a propane/butane mix for start up, I have had absolutely no problems using just propane (the green Coleman stuff.) I do not use an onboard propane tank.

Regards,
...jim