

Instead of springs, this design uses Powered Wheels. Attach two or more springs between the top of the arch and the midpoint of the arm.Connect the hinge and holder with Wooden Poles.Place a placeholder log facing backwards at the back of the vehicle and place a Holder and Bomb on top, at the end.This crossbeam will stop the arm at the right moment, flinging the projectile forward.Form an arch of Logs at the front of the vehicle with two upright logs and a crossbeam at the top.The obvious catapult design involves using Contractible Springs to pull the arm.

They're a fairly foolproof starter solution (along with #Traction Trebuchets) for people who need bombs flung to high places (e.g. Onagers (or catapults, as most people know them) work by using tension to pull an arm upward, which then flings the projectile.

You can also build a smaller h-frame with one log, four Small Wooden Blocks, and normal Powered Wheels, and adapt the following siege weapons to it. This will make the frame virtually invincible short of fire or explosives.
