Leonardo da Vinci designed a spring catapult to hurl stones with a spring-powered arm.
His notebooks include compact artillery concepts that used stored mechanical energy rather than relying only on a team pulling a rope or hauling a counterweight. In a spring catapult, bent or twisted material stores energy and releases it through an arm, sending a projectile forward.
This design belongs to Leonardo’s broader interest in siege engineering. He studied older weapons while attempting to improve their range, speed, portability, or visual impact. The surviving drawings are engineering proposals, not proof that every machine reached a usable battlefield form.
A catapult is a broad class of projectile-launching machine. Leonardo also drew a giant crossbow and other artillery devices, so the spring mechanism is the identifying feature in this design.