How does a trebuchet work?

Answer 1

A trebuchet is like a big catapult. Debris is loaded into the sling aparatus and it is slung by releasing a large arm.

Actually, a catapult and a trebuchet work on completely different physics principles.

A catapult works on the principle of torsion - the catapult arm is inserted into a twisted length of rope. When pulled downward, the increased torsion of the rope stores energy, which is released in the "untwisting" motion of the rope, causing the catapult arm to return to the original position (straight up). The limit of the catapult's effectiveness is defined by the amount of torsion that the rope can hold, which, in general, it defined by how strong the frame of the catapult can be made. Using fiber rope, wood, and human power (to twist the rope itself), ancient catapults were limited to a payload of several dozen pounds, being thrown no more than 200-300 yards.

A trebuchet, on the other hand, is a simple counterbalanced lever. It operates very much like a playground teeter-totter (see-saw). The very long arm has the pivot attached close to one end (generally, about 10% of the length of the arm), with a large counterweight (usually, a box filled with rocks or iron pellets) attached to the short end. The long end has a rope sling attached to it. Pulling the arm don to a horizontal orientation (from it's "natural" vertical one), stores potential energy equal to the weight of the counterbalance. When the arm is released, gravity pulls the counterweight down, and the arm swings up quickly. At the top of the arm's arc, the sling is released, throwing the payload.

Overall, imagine a large person sitting on a see-saw, where the see-saw pivot point has been moved close to the large person. Then, a number of other people push down on the other end, raising the large person into the air. A small person then gets on this end (the one being held down by the group). When the group lets go, the large person crashed back down, and the small person quickly shoots up, often flying off the see-saw. The trebuchet works in an identical manner.

Answer 2

A trebuchet can throw a rather heavy object over the walls of a castle or city. Stones weighing hundreds of kilograms could be thrown hundreds of meters.

There was an episode of Northern Exposure that centered on the construction and use of a trebuchet. Originally intended to be used to fling a cow as an artistic expression, that use was abandoned when Chris found out Monty Python had already done it. In the final scene, the trebuchet tossed an upright piano that had been damaged beyond repair across a field. In medieval times, trebuchets were much larger and could throw heavier and potentially more destructive objects.