Quote Originally Posted by Ropey View Post
Knew a guy who was so good at it, the rings would shoot out from his mouth and travel more than halfway across the room before starting to dissipate. They had an interesting internal rotation that's hard to describe where the inner part of the ring would spin and become the outer part of the ring. I think this gave them some sort of structural integrity as he could blow them even in a breeze.
Actually ALL smoke rings have this property: they are a vortex and stable because of the angular momentum producing inertia. The reason that some smoke rings travel further is that the vortex is spinning quicker, therefore has a higher angular momentum which takes longer to lose energy to the surroundings and therefore travels further.

An analogy is the idea of a bicycle: when the wheels are spinning it is easy to remain upright, but when you come to a stop you fall over. With a faster initial speed the bike will travel further before stopping.

What's really cool is that Dolphins are the masters of toroidal vortices...
https://www.youtube.com/watch?v=2m6ie3MVIAw