[EricH]

Originally Posted by jkelleyrtp

What kind of force is needed? I saw a supershifter demo with a servo that put out around 9 lbs but it was no where near as snappy as the pistons.

9 lbf is not a legal FRC servo. Unless it's insanely slow... servos are only 4W in FRC, and I find it very difficult to comprehend a 9 lb force out of a 4W servo. Also, factor in the load of a moving drivetrain.

60 psi on a 3/4" diameter cross-section seems to do the trick nicely.