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Da Vinci’s Catapult
The Da Vinci Spring Leaf Catapult
Leonardo Da Vinci was a man who wore many hats: painter, sculptor, and innovator. In his spare time, he was known to sketch mechanized throwing devices. Although the essential catapult design had already been conceived and put to use for a great number of years before his time, Leonardo’s creative mind saw room for improvement nonetheless.
Da Vinci recognized a simple fact that was likely overlooked by most: that gun powder, albeit a resourceful substance, was not 100% dependable while in the line of fire. For this reason, Da Vinci validated the catapult as an enduring and competent tool in warfare. It just needed a bit of tweaking.
Expanding on the Basic Concept
Sometime during the 1480’s Da Vinci drafted two designs using a leaf spring system: the single arm catapult and the double arm catapult. The brilliance of his model was that, contrary to the conventional way of using a bow to draw the throwing arm upwards to its ready position, a rotating drum was introduced which would spin swiftly on an axel connected to the arm. The mechanism would enable a significant increase in the throwing arm speed, without an overexertion of physical force upon its release. The effect could be compared to the spin motion of pulling a ripcord to start a gas engine.
The leaf spring section would have replaced the bow component seen on the standard catapult. Like the bow, a leaf spring system is broader at the middle, making it harder to flex. As it narrows out at the extremities, it becomes much more pliable. But because of the physics involved with the leaf spring assembly (layering wooden slats in decreasing lengths), a greater curvature can be achieved, and subsequently, greater propellant power.
The Single Arm Catapult
For the single arm catapult, a long post would be inserted into the drum barrel, from which the throwing or “swing” arm could be set into launching position. There would be a cup at the end of the extension to hold the projectile in place, similar in appearance to a slightly hollowed out boating oar. The gentle scoop of the throwing cup was to help make the ammunition release as efficient as possible when fired. The single arm catapult would use a ratchet system to move the swing arm into place, locking securely with each toothy click so that accidental ejection could be avoided. When ready, the catapult could be engaged by hitting the release mechanism.
The Double Arm Catapult
Da Vinci had a somewhat different design in mind for the double arm catapult. Basically, a worm gear system winding a very large wheel would be used to gradually set the throwing arm into its final firing position. This distinct apparatus was made to improve on leverage for the dual arms, while holding back such fierce amounts of tension safely.
Design Drawbacks
- Creating a better, more durable steel leaf spring system might have proved challenging due to the need to flex so many large sections of steel into layers.
- The considerable cost to produce the steel mechanism would probably have been enough to shelve the plan altogether.
- It is believed that the swing arm tension would have been tremendous, most likely extreme, even if some type of high-grade, laminated lumber had been used in its construction.
Leonardo Da Vinci could often be found soliciting his innovative ideas to kings, noblemen and governors in an effort to not only enhance security around their cherished castles and fortresses, but also to strengthen their defences on the battlefield. Although history has not determined whether or not either of the two Da Vinci catapult creations were ever built or employed in combat, their legacy will undoubtedly continue to capture the imagination of young inventive minds for generations to come.