Week Nine: Sin-ew

Hey everyone, and welcome to what is one of the final installments of Ballistas and Battle Rams.

Vitruvius does something very interesting with his schematics in the way he takes a lot of things for granted. One of the key components of any ballista is the slide and trigger. You’d expect something this important to have a lot of description, but if you simply read the texts at face value, it would all be rectangles. There’s not really a good description on how the trigger interlocks, where it goes in relative position, and how the slide is designed. This means I have to do a lot of groundwork in creating the design. 

Take the slide for example. There’s no real talk about it other than the length, which I try to keep as faithful as possible. In terms of the trigger and claw, there’s not much other than the Greek words that are present in the Latin. I’m sure, given infinite time, I could recreate the machine to a higher degree of perfection, researching the Graecan engineers of Heron and Philon, but I must make do. 

So I landed on a makeshift gear system. The arms are tied with excess artificial sinew (don’t get me started on sinew) and pulled back by a single block, with small rails to keep it straight. A small divot at a specific length is where it slides in, and a trigger holds it in place. To make it more stable, a DIY windlass (essentially a rope on a cylinder) is used for better pullback, as instructed by Vitruvius. Pulling back on the trigger releases the block, launching the block and arms into resting state, throwing whatever projectile. 

Theoretically, if not for the existence of sinew. The main component of the entire build is the elastic that keeps the arms taut. Sinew is traditionally animal tendons, which store lots of power. However, the artificial sinew I have chosen to use for efficiency, came thinner than I thought. This means it takes a lot more of it than the thicker ropes you see in other builds, so I’m a little delayed in wrapping it up for use. This sucks, and it’s something I should have accounted for, but it’s more manual labor than problem solving. 

Be tuned for next week’s blog post for the final results [If you’re really sneaky, you might even find it in the Drive before the blog goes live].

Signing Off,

Aadrit T.