Erm, my fav robots are Little Hitter, Tiny Toon (not relevent lol), b-e-t-a, basher

I have a nearly finished robot at circa 6kg. Was umming and arring about building another for a cluster or armour this more and going with a big hammer, although then it won't be invertable.

So was looking into it and most are pneumatic, but would rather go electric and wanted to see if I'd be able to sort out a big enough motor with a 6kg allowance. To be honest I don't know what ratio to be looking at, I think it'd depend on the motor. I'd hoped it would be manageable with something like a pair of wiper motors etc. But if it needed something like a wheelchair motor in I'd never do it in the weight I don't think.