OK .. here is ... the idea is to make two pivots soldered in the "T" letter. Then drill a hole of the same diameter the shaft is in the thicknest place of the airfoil. If the fitting of the hole and the pivot is enough tight you won't have to do nothing more to get the nice rotating of the movable wing and its leading edge down. Thanks to that you will get the outher wing set 90 degrees vertically. The second pivot is for folding the wing towards back. For mounting of the shaft you have to take a cube of polistyrene and drill through it a hole of the shaft daimeter. Also you have to drill the second hole but to the half distance in the cube. Then there you have to remove some of plastic in order to get a kind of a "gutter" that allows the wing to be rotated/moved towards the tail. It should be at the bottom of the wing because it won't be seen there. Of course you also have to make the "gutter" for the slot going through the cube. But when the "T" shaft is put into the "gutter" its both endings have to be closed with fitted pieces of the polistyrene to protect the "T" shaft aginst falling out from the cube. I have marked the pice with the red colour on the cube. The "T" shaft and the cube have to be made and assembled firstly and then the whole hinge should be fitted to the wings.