Leonardo da Vinci redesigned a catapult with a large spring-like arm for launching projectiles.
Leonardo’s military notebooks contain several catapult studies. His versions use mechanical systems to store energy and release it suddenly, sending a stone or other projectile toward a target. Some drawings show a large flexible element and a winding mechanism that would have made the machine easier to load.
The catapult was an ancient weapon long before Leonardo. His importance lies in applying Renaissance engineering analysis to its proportions, materials, leverage, and operation. He often explored multiple alternatives rather than presenting one finalized machine.
Catapults are often confused with trebuchets and ballistae. A trebuchet uses a pivoting throwing beam, commonly powered by a counterweight or traction. A ballista is a large crossbow-like weapon. Leonardo studied several of these families of siege machinery, so identifying the launching mechanism is essential when naming a particular design.