How the Trebuchet Works A trebuchet works by using the energy of a raised counterweight to throw a projectile. A long beam is attached to an axle. At the short end of the beam is attached the counter weight. The long end of the beam is pulled down, raising the counterweight. A sling, which has a pouch containing the projectile, is attached to the long end of the beam. Upon releasing the trigger, the sling and the beam swing upward, pivoting on the axle toward the vertical position, whereupon one end of the sling releases, opening the pouch and allowing the projectile to fly towards the target. The stored energy of the counterweight is transferred efficiently to the projectile.
The Use of the Trebuchet The exact beginning of trebuchets is not known but we do know that they first started appearing around the 12th century.
There were similar siege engines that date back as far as the 6th century but these were human powered rather than gravity powered with counterweights.
The human power was the act of pulling ropes rather than having a counterweight.
What we officially recognize as a trebuchet is powered by a counterweight, has a sling and a long pivoted throwing arm.
The trebuchet worked great against even the strongest fortressess. They could hurl larger stones over longer distances and with tremendous force.
There are three major things about trebuchets that make them unique. The use of a long throw arm on a pivot, the use of a counterweight and the use of a sling. And the First reliable mentions of these characteristics occurred in the 12th and 13th centuries.