We built a pneumatic catapult. Nothing fancy, just two somewhat largeish cylinders (lot smaller than one behemoth I've seen), two double solenoids, and a swiss-cheesed bar of c-channel. We were finalists at Traverse City.
Pneumatic catapults WORK.
*The losses in finals were probably because of our drive chain literally falling off.
Edit: after reading the following comments - we don't need no stinking pulsing.
