Trebuchet
What is a trebuchet?
In general, the mechanical artillery of medieval times was inferior to that of the Classical world. The one exception was the trebuchet, an engine worked by counterpoise. Counterpoise engines appeared in the 12th century and largely replaced torsion engines by the middle of the 13th.
Construction (pdf)
The trebuchet worked something
like a seesaw. Suspended from an elevated wooden frame, the arm of
the trebuchet pivoted from a point about one-quarter of the way down
its length. A large weight, or counterpoise, was suspended from the
short end, and the long end was fitted with a hollowed-out spoon like
cavity or a sling. (A sling added substantially to the trebuchet's
range.) The long end was winched down, raising the counterpoise; a
stone or other missile was put into the spoon or sling, and the arm
was released to fly upward, hurling the missile in a high, looping
arc toward its target. Though almost anything could be thrown, spherical
projectiles of cut stone were the ammunition.
Trebuchets might have a fixed counterpoise, a pivoted counterpoise, or a counterpoise that could be slid up and down the arm to adjust for range. Ropes were frequently attached to the counterpoise to be pulled on for extra power. Modern experiments suggest that a trebuchet with an arm about 50 feet (15 meters) long would have been capable of throwing a 300-pound (135-kilogram) stone to a distance of 300 yards (275 meters); such a trebuchet would have had a counterpoise of about 10 tons.
Though the rate of fire was slow, and prodigious quantities of timber and labor were required to build and serve one, a large trebuchet could do serious damage to stone fortifications. The machines were apparently quite accurate, and small trebuchets were useful in sweeping parapets of archers and crossbowmen.
What is the difference between a trebuchet and a catapult?
Trebuchet is powered by counterweight whereas catapult is operated by a sudden release of tension on wooden beam or twisted cords of horsehair, gut, sinew, or other fibers.
