Has anyone tried using a 21 by 32 inch base using the kit box base.
Probably someone has, and it would be possible to cut the frame to meet those specs. I would caution you to do some math on turning scrub to make sure this is what you want to do. I would recommend checking out this whitepaper on the topic: Drive Train Basics.
While I don’t remember the exact dimensions, my team went with a long, narrow chassis for the 2016 game. It had 4 wheels and didn’t turn particularly well. I would not recommend that geometry given that turning and manueverability will likely be negatively impacted. Of course, it depends entirely on your team’s game strategy, and you could try adding 8WD or omni wheels, which would make turning with a 21"x32" chassis easier.
Close. 22x32 I think. Our 2018 robot.
You can imagine we had to modify the wheel channels to squeeze closer together. It is maybe different that they flipped the outside plates in 2020 (iirc).
Edit: We also didn’t power all 6 wheels, we had 4 powered traction wheels and 2 front omnis. Weight was distributed towards back. That may be possible if you approach the charge station in one direction. The turning was very good with the omnis. But the long frame may make climbing more difficult. In 2019 we took this robot to an off-season and thought to make it a hab level 2 but the length made it extra difficult to work, so I don’t know how that would do against the charge ramp.
Edit2: Memory is not always clear. disregard
This is really good advice, here’s how making the frame of that size would work:
Assuming 21” wide by 32” long, this can be done. You would assemble kit bot with the long chasis configuration where it would be 32.3” long and a custom width wide: the front and back would be cut to 21”, the churro to 12.25”.
Disclaimer: if you are using CIMs in your drive train with stock gear boxes there might not be enough width for them if you cut the front and back rails to 21”. Some CAD work might be required.
Edit: As @Ethan_Reed clarified 22" is as small as you can go.
I’d imagine that the turning scrub would really bad and you would probably want omnis on the corners.
This is correct. You want at least 22" wide for your kit chassis so that you can drop a single CIM motor out of your drive gearbox.