http://www.modelaircraft.org/templat...k/rc-pylon.pdf
AMA competition rules page... pylon racing .... go to section 7.4 for the pylon racing rule that says... you have to have the spinner or safety nut. It doesn't say "AMA Safety Nut".... but the requirement adds up to it.
Now I've absolutely proven All the places I said DEFINITELY would reference it do reference it.... I'm not going to bother with the CL sections, because... I said:
The minimum radius rule is in the Pylon racing regulations... I beleve also in the RC combat regs. It may also be in some of the CL competition regs... There is such a thing as an "AMA Safety nut (which is essentially a large "acorn" nut) But its only required for certain types of competition.
RC Pattern Aerobatics rules have a minimum radius for the LE of the wing... but no spinner required.
But... do you want me to pull up the reference on leading edge radius for Pattern?
Be a good butthole... look it up yourself. Its there.