[EricH]

Originally Posted by farmersvilleRob

Well I need a lot of speed. preferably as close to 0 as possible.

But in reality weight is an issue, and I would like for it to be extremely lightweight.

The VEX motor does 60 degrees in .01 seconds so that's good!
But it's only got ~216 ounce inches of torque :/
And it weighs .2 pounds which is fine.

Now I guess I could put a gearbox to the motor, but that makes it too heavy.

Gang two VEX motors. Use VEX gears to link them and an output gear on a rail. VEX gears are light; I don't think the entire setup would weigh over a pound, rail included.