Brief Description:  A medieval catapult, most commonly referring to a torsion-powered mangonel or onager, was a heavy siege engine used to launch heavy payloads. It featured a sturdy wooden frame, a central throwing arm suspended in a twisted rope spring, and a sling or bucket. When winched backward, this tension provided the explosive force to hurl projectiles.

Main Components:

The Frame: Constructed primarily of heavy, seasoned oak or timber, the main base was a robust wooden platform. It was often mounted on wooden wheels for battlefield mobility or kept stationary on flat-bottomed logs during a long siege.

The Arm: A long vertical lever with a spoon-shaped bucket or a flexible rope sling attached to the top end to hold the projectile.

Torsion Springs: The true power of the catapult came from a massive skein of tightly coiled rope made from horsehair, sinew, or gut. The base of the throwing arm passed directly through the center of this coil.

Operation Mechanism:

Winding/Loading: Operators used a hand-cranked winch and windlass system to pull the throwing arm downward, twisting the coiled rope even further to build up immense potential energy.

Securing the Arm: Once the arm was pulled back nearly flush with the ground, it was locked into place with a heavy slip-hook or trigger mechanism. The projectile was then placed in the bucket or sling.

Release: When the slip-hook was released, the sudden unwinding of the twisted sinew sent the throwing arm swinging upward with violent force. The payload was released at the peak of the arc, sailing distances up to 300 to 400 yards depending on the machine's size.

These engines were versatile indirect-fire weapons capable of hurling various objects:

Stone boulders: Used to smash through castle battlements or clear troops off the walls.

Incendiary materials: Pitch, tar, or fire baskets designed to ignite wooden sections of a fortress.

Psychological warfare items: Decapitated enemy heads or rotting animal carcasses were launched into besieged cities to spread disease and strike terror among the populace. à½.·—.