The flatter sides of the airfoil tube section get less pressure from the tension in the tape than the radii of the leading and trailing edges. This image shows the rubber mold I made to shape the carbon around the dropout. On the left is the dropout. I show it covered with a thin layer of brown modeling clay which represents the thickness of the carbon. On the right is the rubber mold, a negative shape of the dropout.
Wax paper is used to keep the clay off the workbench.
I am quite proud of this image. It shows the clay mock up of the frame near the front derailleur. I installed the derailleur on this plate to determine the clearance I needed in the clay. Just after this photo was taken I poured plaster into this cavity to make a negative mold of these contours. Together, I used the plaster and the rubber to mold the carbon fiber patch that has the desired shape.