1. The problem statement, all variables and given/known data The teacher said it is possible to use an epicyclic gearing with no axis fixed but nobody use the gearing like that. I watched this video: at time 42s it's possible to watch it. I have 2 questions: 1) Is it possible to used the epicycloidal train with no axis fixed ? 2) If yes, what is the ratio of reduction ? is it dependant of the torque ? Maybe if you have a link ? 2. Relevant equations -- 3. The attempt at a solution I'm looking for this case, but each time the epicyclic gearing is used with one fixed axis.