I was taking the box off and noticed the skid pad had popped off of one of the retaining screws.
The weakness around the counterbored screw went through my mind during design but it's not an easy issue to side-step. I could double the number of screws... But I think it's time to upgrade to the nylon wheel version. (Custom cut nylon wheels on a pair of idler pulleys.)
(No picture), I've also noticed the caster I put on the bottom of the box has taken some marring. My guess is that it has grounded over more than one dip, and since it was unexpected it ended up taking a little impact. I'm glad the caster is there, and glad the frame is hinged. For having a boattail at 12-13 degree departure angle, I'm pleased with the practicality of this design. (Give or take pending aero details...)
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Still slowly, slowly chugging away on coast-down... maybe doing the next Kammback AB test this week or next...