Toy Catapult

This miniature catapult uses a standard hair elastic to propel either the included dodecahedron, or a ping-pong ball using the swappable ammo baskets. The printed screw adjusts the power by pulling the elastic tighter or looser, with a numeric gauge along the sides so you can track the trajectory.

The trigger part (and some of the base part) needs supports as shown, for which I've included a support enforcer in the .3mf file. The screw part needs to be printed upright for the threads to work, so I modeled a custom support structure that keeps it sturdy, but can then be clipped off easily.

The little spring component of the trigger ensures that the arm is pushed well over-center of the pivot/elastic axis. Together with the catch, they should load the spring a bit before releasing the arm, giving it a good shove as the elastic starts pulling. 

Holes in the base part can be used to screw it down to a piece of wood, or another printed base that allows for angular adjustment!