If you look closely at these three pictures, you'll see a few similar things: a base, an arch to stop the arm, and a bar across the base that the arm pivots on. Naturally, this is what our catapult has got as well. insert pictures of our catapult
Originally, we had a design like this one, where the arm was bungee corded to the posts near the front and to the base. The cool part about this idea is in order to release the arm, you would crank the lower bar, then release. The bar would spin, the bungee cord unravel, and the arm would fly towards the frontal posts.
The issue with this design is that it's real easy to do when working with wood... but not so much with PVC pipe. So, we transitioned more towards what was shown earlier:
Average distance: 244 inches (just over 20 feet). Our maximum height is 65.8 inches, which makes our average vertex (122, 65.8).
Quadratic equation in vertex form: y=-(5.48/12403)(x-122)+65.8