Spent the afternoon studying the plans and cutting down the rest of my wing ribs. For those that don't know, the BD-4 had a unique wing building technique. A tubular spar was carried through the cabin, and 10 feet out each side. Wing buckets were then slid over the spar, glued together and secured to the wing. These formed the fuel tanks when sealed, and the structure of the wings. Unfortunately, as all wing tanks will do, leaks occurred. This created problems as you might imagine. It was discovered that the wing tank sealant was very effective as long as it was kept wet by the fuel it was sealing in. If it was allowed to dry due to low fuel levels, maintenance, inactivity-leaks would occur. The BD-4 factory answer is to use aluminum honeycomb panels, cut to shape as wing ribs, slide these over the spar, glue into place, and to wrap aluminum sheet to create the airfoil shape. The aluminum sheet is adhered to the honeycomb panels with Pro-seal. This also serves to seal the bays that are used for fuel. The honeycomb panels are expensive, and I already had perfectly formed ribs available to me. My plan is to use the cut down panels as wing ribs, adhere them to the spar, then wrap the wing and adhere it to the ribs with pro-seal. The rest of the wing will be built to plan.