Blog Post 10: The final steps.

Hey everyone and welcome back to your favorite blog series. Let’s jump right in.

My time has been weaning off of engineering and more towards presentation now that the final deadline is coming up. But worry not, engineering stories are still present. If you look at the drive, you can faintly see the improvement of the design up to the present.

Many things have been happening that the blog posts may not have covered. One of which is that the machine works. The arms are finally stretched and supported with metal beams, and tied with a sinew rope to the block trigger. A lot of this was improvisation as many parts aren’t described by Vitruvius, but just called the Greek name. My hypothesis is that for ancient engineers, these are staple terms, like how we would understand what a pulley is without mechanical descriptions.

But in either case, the block trigger was causing the most problems. Too much stress one direction and friction would stop the machine. Too much in the other and it would fly away. My solution? Building a system of rails on the support beams, and having an H shaped block to hook onto the rails. That way, vertical motion is controlled, while horizontal is still kept in check by the larger beams.

The rope was also changed for the windlass to a less sticky nylon. One of the problems was that the windup was getting jammed because the sinew was too sticky of a material. I think, while there’s no real description of this, that this is the intended solution, because it would make sense for the ropes to be of a fiber and the elastic of sinew.

Another interesting thing I found out was that ancient engineers actually had a method of testing tightness uniformly. Vitruvius writes that the machines are wound up and tested to be on the same note. As in, a tight string being strummed to compare how wound it is. I find this very interesting, especially because it’s a pretty accurate system for people who didn’t have much else to work with. But alas, he doesn’t say what note it is, so I can’t tune it properly. Nor do I think I would get to the same place.

My machine is way less powerful than what Vitruvius and engineers would like, partly because I made it that way. The sinew bands are much thinner than normal because I didn’t want it to go out of control, and I was right. Even with my limited strength, it was already putting a lot of pressure on my build. With the right tools, it can be improved. but the weakness right now is optimal. But fear not. The drive has a few videos of the block snapping back to throw the pole I use as a bolt a non-negligible distance. And that, to me, is a win.

I hope to see you all on Saturday’s presentation, where I will be bringing in my build for display (but not testing, because I’m not that crazy).

Signing off for the penultimate time (right?),

Aadrit T