The ribs come pre-cut. Still a lot of work to do to get them shaped right and smooth the tooling marks. Specifically the edge of the lightening holes needs to extra smooth as we don’t want any concentration of stress which can lead to cracks. There are lots of ribs and even more holes to work on. L-Angle stiffeners are used on the ribs and a U-channel to reinforce the area where the Aileron Bellcrank will go.