Traction Catapults - Siege Weapon Technology Advances

Traction catapults were the next step in medieval catapult technology, using the same basic design as torsion catapults while replacing the source of the catapult's power.

Where torsion catapults relied on twisted rope springs (torsion springs) for power, traction catapults used human power to launch rocks and other projectiles great distances.

Traction catapults were lever-based machines designed by ancient engineers to operate quickly and be very accurate. When a human operator pulled down on a lever, the catapult hurled a rock much farther than a person could hope to. The weight of the rock that could be thrown by the catapult was much greater than any human could manage on their own.

Designs for the traction catapult evolved to provide a long throwing arm positioned over a jumping platform. This allowed 2 or more men to jump up and grab onto handles or ropes attached to the throwing arm causing one end of the throwing arm to be pulled down quickly by the weight of the men. This movement caused the other end of the throwing arm (armed with a rock or other projectile) to quickly rise and hurl an object through the air towards the target.

Although they were sometimes called pull-throwers or witches' hair, these catapults were most often referred to as traction catapults.