[Answer42]

Bit of a deviation here. But is a pneumatic catapult really the best option here? Especially considering that you don't already have the system on the robot, it's just one more thing to add along with the catapult. You said you have 30 pounds left, and unless you've used all your cims, mini-cims, and banebots motors you still have plenty of power left. Electrically driven catapults are super simple, requiring you to just hook a gearbox to a shaft via some sort of pulley or chain. No locking mechanism, springs, or pneumatic required. They require complex coding to make accurate shots, but just trussing could be accomplished by something as simple as boom done's system from RI3D. Using a torque limiting belt removes the need for precise control. IMHO it would be the easiest way to add a trussing capability to your robot. But that's just my two cents.