Leonardo da Vinci designed a springald, a torsion-powered stone-throwing weapon with a flexible bow and two curved arms.
A springald resembles a large mechanical crossbow but uses a frame and powerful arms to store energy. Leonardo’s sketches show a compact siege engine intended to launch stones or other heavy projectiles. The design reflects his interest in improving military machines through careful study of force, leverage, and mechanical motion.
The springald was not the same as a trebuchet, which uses a swinging beam, or a ballista, whose traditional form uses torsion bundles to propel a bolt. Leonardo’s version belongs to a long history of siege-engine development rather than to modern artillery.
There is no firm evidence that Leonardo’s particular springald was built and field-tested. His drawings remain valuable because they document how Renaissance engineers analyzed and redesigned older weapons.