I may have talked about this in an old post.. turns out to keep centrifical force constant, a loop is not circular, but rather an ellipse:
This is mostly done for the purpose of reducing g's on the human body. I figure if you're talking about a pinball with constant velocity (IE: same force holding it against the ramp as it goes around), this is also ideal. If the force changes, that could be what makes it >pop< out of the track.
SO! Now that 3d printed pinball parts are popping out of my machine, it's time to revisit that concept in PLA. So let's look at the loop ramp I started before:
Going to print it tonight since it's a 4.5 hour job even on fast speed. I'm going to try to print as a single piece without support. In theory because of it's shape it should be self supporting.