I've built combustion PVC cannons before, but I'm interested in a pneumatic cannon that can launch volleyballs at variable speeds between 5 and 40 mph, if possible, to simulate sets and serves. With a volleyball's large and slightly variable diameter (a little over 8"), I suspect it will be better t...

I need some suggestions. :dontknow: I want to create an adjustable mounted pneumatic cannon that will shoot volleyballs at variable speeds (5 - 30 mph) to emulate serves and sets, as well as potentially on a downward trajectory for digging (bonus), and perhaps with an adjustable degree of topspin :s...