Thank you Anthony.
It's a hobby for me, plus a learning experience.
Do you need 16 decimal digits for RADIUS?
I should spend a little time getting familiar with the terminology & formulas...

There could be an initial menu with which to select "Fan" or "Predator", or "Piaggio", etc., with the
hidden (multiple?) parameter input menu(s) then activated, or maybe pass the parameter list to one menu?

But for now, the menu is enough for testing. Time to continue work on the .js script.
:-)

If you see anything objectionable, please speak up.
I'm resolving to resist the urge to rename variables.
Data types will be integer or javascript decimal...