What Would a Constant-G Roller Coaster Loop Look Like?

[curiousnoncat]

I was reading this interesting article on different varieties of roller coaster loops, and I know nothing about calculus or ODEs, but I was wondering what the constant-g loop in section 3.2 would actually look like for some typical initial velocity. Is it conceivably possible for a rider to experience 1 g throughout an entire loop in a 1 g environment? I would have to disagree with the author, then, because it would truly be an interesting sensation.

 

[mfb]

If the loop is not complete (starts with an upwards section and ends with a downwards section), having a constant 1 g is possible. You cannot have a full circle, of course, as this would add centrifugal/centripetal acceleration with gravity, and give more than 1 g.

 

[FactChecker]

You would have to tighten the loop radius at the top so that there are 2 Gs, ignoring gravity. And you would have to take into account any velocity decrease going up and a corresponding increase going down. I think that the "loop" would not end where it began, but would be forward of the starting point. Without doing calculations, it seems possible to me.