Hi everyone, after finishing the upgrades to Pressure Point and with plenty of time remaining until the events start up again, I have decided it’s time to build another featherweight. I have been working on it sporadically over the winter has time as allowed and decided I better get a build diary up before I forget what I did.

The aim for this one is to be fairly simple, I want something that I can throw into the arena, hopefully come out still working, charge the batteries and then throw it back in for the next fight without too much other work. I also have not fought any spinners yet and this will allow me to see what works and what doesn't before committing too much. Therefore I’m going with a 4wd ram bot, this should keep the design and internals fairly straightforward. It’s going to be constructed out of 1 type of material, HDPE which should keep costs down as I can make all the parts myself. The fixings will be kept all identical where possible to further aid with this. Motive power will come from 4 of the mighty Argos value drill motors, each one directly driving a wheel and each side pair of motors driven off 1 TZ85A flashed to brushed motor operation. Voltage will be as 5s as it gives a good speed/power boost to the motors and they seem to handle it without too many complaints.

With the above in mind, I set about coming up with a design on Fusion 360, its a fairly standard invertible 4wd ram bot type design. The chassis bulkheads are all 20mm HDPE witht the mounts for the motors milled directly into them. Side and rear armour is also 20mm HDPE, while the top and bottom are 15mm. The front wedge is 30mm thick but I think I might end up needing a small steel running strip along the sharp end of the wedge as the HDPE won’t hold the edge, but that should be the only non HDPE part. Fusion puts the weight in at around 11.7kg, so hopefully a bit of scope for it inevitably weighing more than you expect. The name of the machine shall be Plastic Fantastic since it is built out of the stuff.

The HDPE came from Direct Plastics, all natural white as I’ll come up with some sort of decoration scheme when it’s done. Fusion 360 spits out g-code from its CAM module that I can send straight to my CNC router so it wasn’t too long before the first part was made. It’s one of the main bulkheads that surrounds the battery compartment, and here it is before it was cleaned up.

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A couple more parts later and there is the other battery compartment bulkhead along with one internal side. You can see the mounts for the front of the motors in it. Apologies for the poor picture but its the only one I have of it at this stage.

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More to come soon.