I'm kind of a long-time lurker here, but never actually posted here before or made a robot.
Anyway, a long time ago I had this idea for a novel kind of spinner - probably the worst possible first robot, but I am tempted to give it a go nonetheless...
Basically, it's a kind of invertible ring spinner, where all the electronics etc are contained within a frameless brushless motor like this:
The stator (on the right) would be fixed to the chassis, with all the electronics/mechnicals crammed inside the central hollow. The rotor (on the left), would spin around the outside, with some blades attached of course.
The whole thing would be in the form of a flat disc, with the wheels protruding top and bottom to allow it to run both ways up - similar to these:
http://vignette1.wikia.nocookie.net/bat ... 1217205930
http://www.swindon-makerspace.org/wp-co ... yrobot.jpg
Really, it's much like a conventional full-body or ring spinner, but takes the concept one step further, by combining not only the armour and weapon, but also the weapon motor, all into one component.
It might even be possible to mount fan blades on the rotor, above the stator coils, to generate downforce (so it might be less inclined to fly across the arena when it hits something), and to draw air over the coils to cool them.
Obviously there would be significant obstacles to overcome: mainly getting all the electronics to fit in such a small space (might be better suited to a heavier weight class without the size restriction?), keeping it all within the weight limit, and finding some sturdy enough bearings.
The frameless motor would need to be custom made too, as they are not cheap, light or widely available, but that seems do-able, with a 3D printed air-core stator (magnet wire and tiny neodymium magnets are both easy to get hold of).
On the plus side, it would only need enough drive to not be considered immobile, and it wouldn't really need armour, so virtually all the weight allowance could go into the weapon system. Also, there wouldn't be the usual issue with ring spinners of how to get drive to the spinning shell.
Anyway, just thought I'd share my crazy idea...
