This is a link to a Google 3D SketchUp drawing for a desktop trebuchet. You will need the SketchUp software to download this drawing and its freely available online. We do not provide support for this software.
Cathy, the program director, was looking for something neat to do as a lobby activity. Something the kids can do during free time. She suggested a catapult.
What you want is a trebuchet, I said. A catapult uses a throwing arm under torsion. It needs to be hauled back to lock and load. A trebuchet, on the other hand, uses a counterweight which could be unloaded so that kids operating it don not have their teeth knocked out by a misfire. I got the job. 🙂
After discovering that the double sized-trebuchet I had built for the Carnegie Science Center was, in fact, too big, I went back and divided all my measurements in half. This gave me a machine nearly identical in dimensions to the Cheesechucker machine I had originally copied.