pic: 1648 Teaser/Waterjet part count

[Electronica1]

I will give this a guess, the two big identical pieces in the middle of the picture appear to be an arm pivot so I think that is for your catapult. The pieces at the very top appear to be a smaller version of the pivot so maybe that is for the pivots for your pick up/intake. I think the gusset for your 8020 have been already noticed. I see a small cam with a hex hole so I assume that is what you are using to reload. I think the part in the bottom left has some motor mounts so that is where your cam might be going. Also that part with the rectangular hole is ... a gearbox, maybe?