That looks exactly like an old Lanier Jester.
They had a wooden crutch interior fuselage structure with a molded plastic shell to give it the shape. The wings were foam core covered with plastic sheeting, and so were the fin and stab. I found a photo of a Jester on RCU and it looks exactly like yours, except for the colors.
If it's the early version, they were called a Citron. The name was changed later to Jester to avoid a royalty conflict with Jim Kirkland. Same plane, but different name. I also found a photo of the box label of the Jester.