Leonardo da Vinci’s machine using a large spring to launch projectiles was a catapult.
Leonardo designed several military machines, including catapults that stored energy in bent wood, twisted cords, or large springs. When released, the stored energy drove an arm forward and launched a stone or other projectile. His drawings show careful attention to leverage, tension, and the timing of the release mechanism.
The catapult was an ancient type of siege weapon long before Leonardo’s lifetime. Leonardo’s contribution was to redesign and analyze mechanisms with the engineering methods visible throughout his notebooks. He explored ways to increase range, improve loading, and make the release more efficient.
A catapult is a broad category, so Leonardo’s sketches should not be treated as one single standardized model. A ballista launches projectiles with a bow-like tension system, while a trebuchet uses a counterweight or traction system. Leonardo’s spring-driven machines are classified as catapults because they use stored mechanical energy to throw a projectile.