There are several designs for horse-drawn scythes which were mounted in a manner similar to helicopter blades. Leonardo was a peaceable man who despised war, but this machine, with its rotating scythes, is an absolute horror, in that when operating, it would slice the limbs from its victims, leaving them bleeding and helpless on the ground. Leonardos sketch of this chariot depicts fallen soldiers in their death throes.
It was in 1346 that the English first used cannons which, propelled by exploding gunpowder, fired stone balls. Despite this, progress in that area of military weaponry was not fast, and it was here Leonardo da Vinci particularly applied his thinking. This was an area in which there was plenty which could be done to improve weaponry.
A Typical cannon of Leonardo’s era was cast in iron or bronze, had a short barrel, a short range, and fired cannonballs which fitted very approximately. The first thing we know Leonardo did was design breech-loading cannons against muzzle-loading. They required a fast means of being cooled before firing, and Leonardo calculated that a vat of water could do the trick. By using several cannons in rotation, you could be firing one, loading another, and cooling a third.
Leonardo was the first to measure the penetration of the missile, and to ascertain how to vary it by changing the attitude. During these tests he even managed to launch a rocket-powered cannonball ten thousand feet in the air.