How trebuchet work

A trebuchet works by using the mechanical advantage principle of leverage to propel a stone or other projectile much farther and more accurately than acatapult, which swings off the ground. The sling and the arm swing up to the vertical position, where, mostly assisted by a hook, one end of the sling releases, propelling the projectile towards the target with great force. Much improvement has been made upon the trebuchet. Scientists are still in argument over whether the ancients used wheels to absorb some of the excess kinetic energy and put it back into the projectile. It is known that troughs, frequently rotated in either direction for aiming, were used for the projectile to slide along, thus increasing accuracy.

The mangonel had poorer precision than a trebuchet.The mangonel threw projectiles on a lower trajectory and at a higher velocity than the trebuchet with the aim of destroying walls, rather than hurling projectiles over them.

Recently, it has undergone something of a revival of interest
among historians, hobbyists, and assorted show-offs. While many have been successfully built with a rather wide variety of designs, most work on their design has been highly empirical--little work on the mathematical analysis on their operation and design has appeared. The object of this work is to obtain a fairly complete analysis of the device, so that the ingenuity of the medieval engineers can be more fully appreciated, and modern dabblers in the art can produce more reliable and powerful designs.