Estes Crossbow SST #7207, Build Part 2, Changes & Fin Prep

The engine hook is outside the minimum diameter BT-20 main air frame. I never cared for this look. I'll leave off the hook and retaining ring for a friction fit of the engine.

The picture at the left shows how the notched fins fit over the retaining ring.

On these three fins you can see the notches on the root edges.
Without the retaining ring on the tube the notches aren't needed.

The square corners of the leftover balsa sheet were super glued into the notches.
On the two sub fins (Part I) I didn't cut out a filler piece, it was glued onto the corner of the sheet.
After the glue dried the filler corner was cut oversize and sanded to the sides of the fin.

The three fins with the filler pieces sanded.
The center fill piece on the Vertical Fin (Part H) had a piece cut to size before gluing.