I could have sworn, at some time, that I read that bare engine shaft threads were prohibited...you had to cover them with a spinner or spinner nut with at least 1/4" radius. I didn't think this was in some recommended guidelines, but was part of the Safety Code. Not Combat Competition or anything that selective, but General RC.

The reason I even thought about it is..the little electric planes I have been flying have exposed shafts. You can run a GWS rubber spinner if you have a GWS gearbox with stock shaft, but if you run a collet-style prop adapter then the rubber spinners won't work anymore. I have not flown one without the rubber spinner at an AMA field or event, but I will be shortly...I'd hate to be grounded due to exposed threads on my shaft.

Like I said, I thought this was right up there with no gaseous boost or Benzene (or whatever the prohibited fuel additives are).

And in keeping with the spirit of this thread, I was going to call Art an "Old Goat", but now that I think about it, I don't think I will.