Originally Posted by
BillTodd
The planet set orbits forward 18/66 teeth for each revolution of the sun
The planet revolves (backwards) 66/24 times every orbit
The output ring moves forward 72 teeth every orbit (imagine if the output gear was directly connected to the planet) and backwards 30 teeth each revolution of the planet (imagine the planet stationary).
So, the output rings moves 72-30 * (66/24) teeth each orbit.
The output rings moves 72-30 * (66/24) * (18/66) for each revolution of the sun
Simplifying we get : 42*18/24 = 31.5:1