evil_steve
Joined: 06 Sep 2015
Posts: 304
Location: Adelaide, SA
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Attempt 1: Sworded History
I like chaos, and I like bladed weapons. Therefore, thwackbots are among my favourite bots, especially to drive. Having already built an antweight thwackbot I was keen to scale it all up, but inspired by Gabriel on Robot Wars I wanted something with a powerful drive system. Fortuitously the random bits in my shed provided a solution - old cordless drill gearboxes out of my featherweights (where the original brushed motors had crapped out in combat) mated with some 28-26 outrunners I'd bought on a whim in a Hobbyking sale.
The shafts were the right size so after swapping the pinion gears and bodging up a new baseplate they just fit together. At that time (late 2017/early 2018) SimonK ESCs were readily available and using the Chrome extension RapidFlash it was easy to reflash a couple of Afro 30A ESCs to allow "RC style" forwards/reverse drive via the Afro SimonK dongle. Packing it all into the bot was an issue, but the threaded output shafts/reverse threaded m5 bolts made it easy to attach and retain big wheels.
Sworded History did well, getting 3rd at it's first event, and pretty consistently got 3rd or 4th and most of our beetleweight events through 2018. The drive system has remained essentially unchanged since - I've had to replace one outrunner that had it's wires damaged in a fight.
However the original cutting board chassis didn't hold up so well and I rebuilt it with 3D printed nylon parts (after originally trying 3D printed polycarbonate, which had an unfortunate tendency to shatter under impact). This worked better but was heavier and the wheels became foam to stay in weight. As other local beetleweights also improved and evolved the spinners hit harder, and the front armour went from aluminium to titanium and the blade from mild steel to titanium and then to hardox.
All this made for a durable bot and a crowd pleaser at our bigger events, as it would shred bits of the foam wheels all over the place, take massive hits flinging it around the arena, and throw off pretty sparks from the armour and blade, but still keep driving. But it did less and less well as it wasn't really able to win fights either by KO or on damage, and the need to make a dozen or so wheels for every event became an absolute pain in the arse. The weight of those gearboxes combined with the need for a robust chassis/armour meant that more durable wheels weren't really an option, and ended up limiting the further evolution of the bot.
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