If you’re here, you probably already know about our flagship “Safety Tips: A HEMA Experiment” project. If you don’t, this update won’t make any sense to you so click on the link above and then come back.
We’re in the final stages of preparing for the project with only a handful of details remaining to finalise. The majority of the Kickstarter funds we raised were for setup costs, and that’s where our time has been so far. In short, we needed to build testing apparatus from scratch to make sure the experiments gave good results. The good news is that all of the mechanical components are build, tested and operational. Given that the experiment is this weekend (October 12th/13th), that’s very good news indeed.
Creating the Drop Rig
Most of the build time was spent in on the “Drop Rig”, which is used in Experiment 2: Risk of Puncturing Soft Tissues. In short, we need to be able to perform a controlled drop of a sword. We settled on using several ready-made parts which drastically simplified construction.
We shared this demo of the nearly finalised rig a few days ago. Here we were mostly testing that the rails provided a smooth drop, which they do. The precision of the drop is far better than I hoped – each drop has a variation of a few millimetres at most, unless the sword is vibrating before the drop.
Since then the rig has been developed further. We now have an electromagnetic drop mechanism which allows us to position the sword. We can then still any vibrations in the blade, which means we’ll hit the target dead centre every time. The electro magnet is on a mount that rests on two L-Shaped brackets sticking out to each side. This means that during the test, to raise the drop we simply place spaces of different sizes on both sides of the bracket, allowing us to very quickly change the drop height (and so energy) as we test. This quick change is essential for making sure the experiments can be done in a timely manner.
Augmenting the Mask Stand
Building the rig took most of our time and was the biggest uncertainty in the project. But it’s also only for one of the experiments. The other risk we’re trying to assess is whether tips increase the force transferred to a mask when struck, and Experiment 1: Excessive Force to Mask and Neck is designed to test this. Once again we needed to build our tools.
This was much simpler than the rig. The basic mount is a boxing ball with a spring base that moves easily in all directions. The ball fits snuggly into medium-sized fencing masks. The main part we had to fix was the base, with the original base being too unstable for heavy hits – we wanted to make sure we could hit it as hard as we like, so the base has been upgraded to be wider and made of heavy plywood. We can add further stability by placing heavy weights on top. It barely moved in any of these tests. As well as testing the stability, I was also gathering accelerometer data here – not to analyse, but to make the data collection process as slick as possible. Again, any time saved on the day means we can run more experiments, which is where the real value lies.
Remaining Tasks
So what’s left to do? In terms of prep work, not a lot. The tests above showed that we need to make a few tweaks to how we mount the accelerometer, but this will only take a few minutes. On Thursday night work for the experiment begins with making the ballistic gelatine we will need. We’re using a water bath to control the heat – which helps make sure we can get very clear gelatine by not needing to stir it – and coffee cups as moulds (in true Coffee & HEMA style). The targets need to be made at least 36 hours before the experiment to ensure they have an even consistency.
Friday will then all be prep work: getting accelerometers calibrated, equipment laid out, plastic sword tips made, creating data collection spreadsheets and generally getting it all configured so that on the actual day of the experiment we can do as much testing as possible. Of course we’ll be filming all of it to make sure we can share the results and how we achieved them widely.
We have supplies and hopefully the time to do a total of 3 experiments, starting by testing a rapier with several tipping options, and then 2 of our “stretch” experiments according to our backers’ priorities. If we have a few supplies left over at the end and the time to do it, we may also do “pilot” tests of some of our stretch experiments to see whether they are worth doing in full or if there’s no meaningful test data we can produce.
And of course once the experiments are finished the really hard work comes… maths. We hope to be able to post initial results to backers before the end of the year with final data, full analysis and video sometime in the new year.
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