Leonardo da Vinci designed a catapult with a large rotating drum and throwing arms.
His design used a drum to store and release energy through a spring-like mechanism. When released, the throwing arm could propel a projectile. Leonardo’s version reflects his interest in improving siege equipment by making the energy-storage and release system more controllable.
A catapult is a general class of projectile-launching machine. It is not identical to a trebuchet, which uses a counterweight, or a ballista, which resembles a giant mechanical bow. Leonardo studied several military machines, so identifying the mechanism’s operating principle is important when distinguishing his drawings.
The catapult belongs to Leonardo’s military-engineering notebooks and is not known to have been deployed as a standardized battlefield weapon. His drawings often combined practical mechanisms with proposals that were never built.