Leonardo da Vinci - Catapult

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The basic design of the catapult had been used for hundreds of years before Leonardo da Vinci recorded this device in his notes. The construction depicted in his drawing does not show a leaf spring used in the design, but clearly one would be required to carry the necessary loads without breaking. I have shown a two part leaf spring in this interpretation of the design similar to the English longbow used to great effect in earlier battles at Agincourt and Crecy. Leonardo's genius was in his use of the worm and wheel to load the leaf spring, this led to a simple design that on the one hand allowed the catapult to be loaded with a easy winding action of the handle which gave a large mechanical advantage, and at the same time stopped the drum unwinding. Release of the catapult was achieved by simply disengaging the worm from the wheel by dropping it out of the way.