The next step is to glue the laminated verticals of the drag spar “box”. Time to mention a flaw of laser cutting. While the parts are VERY accurate the edges are not always perpendicular to the flat surfaces of the wood. My guess is this has something to do with the angle of the laser as it “cuts” through the wood. In most cases thins is not an issue. But when edges are matting surfaces it’s something to look out for. The 1st pic shows this flaw when you mate up the verticals to the ply rib. A quick touch on the disc sander and the problem is gone. This is a small issue compared to the accuracy of laser cutting, but it’s something to be aware of.

The top of the drag spar is dry fitted to help with alignment, and the verticals are clamped into place.

The last pic shows a detail of a rib mating up with the dry-fitted top of the drag spar box. Not only is the fitment perfect but also note the bit of added material to the top and vertical. The will allow for a perfect sanded finish following the shape of the ribs. Nice Touch!