I'm planning to put my old and new ideas and designs to this post for commenting. Here is one of them. It flies quite well and the wing is very robust due to carbon fibre rod inside the wing.
The main and tail wing position is movable so you can adjust the balance of the aircraft in many ways. The front weight is a lead bulb inside a styrofoam shield (28g). Also a golf ball can be used as weight (43g). Golf ball as a front weight gives the aircraft unique aerodynamical character.
Wing span: 120cm