I thought it would be nice to archive the progress we've made so far since our humble beginnings last summer (2011), and to map out where we want to be by next summer. 

My first nub design. The angled plate was meant to bend and spring back, but there were problems with repeated cycling at this scale. 

Changing the pivot point for the leg

Concave nub

Roller nub: too costly and difficult to manufacture at this scale

Treadmill nub: just screwing around

First set of nubs ever made (by me)

First design attempt at a retaining nub

Lesson learned: don't make too many modifications without referencing original dimensions

Staged Nub: Possible, but making the molds is very difficult

One of three frames taken of a bb at 1000fps (frames/second). Gave up on measuring rpm

First set of "new" nubs from APD. Too brittle

Active vs Passive concave

Forcing a no-slip condition: Impossible and would lead to MASSIVE overhop with a normal setup, but would make things more consistent

Concept for a filled nub: the filling didn't do much

Reappearance of the angled nub

Appearance of keyed arms/nubs

Appearance of a rotating nub for flat contact from an angular arm

My airfoil round.

Enter H-nubs

First set of prototype keyed arms

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First set of keyed H-nubs

Enter the APD Custom Hopup Chamber (several dimensions are screwed up, leading to the crazy front)

Fixed CS of the APD Hopup Chamber

APD Insert Module: Linear actuation

And here we are.