Although it has now been delayed due to the recent COVID surge, the announcement of an event to take place a bare 10 minutes away from my house finally spurred me get around to creating a fairyweight bot, and I finally have a design that I was happy enough to build. This design is (another) undercutter, bringing my current stable of active bots to 3 different weight classes.
Unlike my 1lb and 3lb designs, the lower weight class all but necessitates mounting the weapon directly to the brushless motor. To give me enough ground clearance to accomplish this I have gone with a modified version of my printed/plate build style, with a carbon fiber plate forming the main structural element that the motor mounts to and a printed electronics compartment slung underneath. I retained the same overall disk design that I have used in my larger undercutters, but to save on weight I had to have it cut from grade 5 titanium instead of my typical AR500 steel. To save on space and weight, I went with a pair of N20 drive motors that have ESCs directly built onto them.
I now have a stable of 3 active undercutter designs across 3 weight classes, with thoughts percolating on the design for a 4th weight class. Now I just need this pandemic to bugger off so I can get around to actually competing with them!