Now that the frame is made, it must be set on the belly shell.
In fact it is the opposite! technically it's the shell that is attached to the frame, but practically, it is similar because they can no longer be dissociated.

Beforehand I strengthens the ribs with 1cm medium wood plates.

In the center, notches are made in the median rib in order to install the U-shaped aluminum profiles that will keep them out straight the triangles. They are glued and screwed.
I begin with the first side :

The second triangle is stuck maintaining the join with tape. Bonding is first performed with cyano then reinforced with Pattex 100%.

Installation of the second aluminum U-profile

At the front, a small piece of wood, shaping the belt sander, is needed.

At the back, the top of the cross is part of the wooden rib and is reinforced with wooden blocks.

The glue used is Pattex 100%. It is solid and remains somewhat flexible. It starts to set after half an hour, but not cured before 2 hours. So the parts need to be hold in place (pliers, tapes...) during curing.