Originally Posted by Harrow
That is because it originally used to come with two wing joiners, as well as two strengtheners in the wing. Later versions saved 20 cents in the manufacture and left the second wing joiner and strengthener out. As a result, some people have managed to break the single wing joiner and destroy their plane.
Got mine somewhere in the middle, after they dropped one of the joiner rods but while the wings still had two metal tubes in each. An aluminum darning needle later I had two joiner rods. It still isn't easy to hold it all in place while mounting the wings. I use painters (low tack) masking tape between the wings to stabilize things while mounting them. Works like a charm.