Here you can download free plans for a foam rc plane.
RC BEECH-18 SCALE MODEL AIRPLANE FLIGHT DEMONSTRATION
How to Make A Plane With DC Motor - Toy Wooden Plane DIY
Homemade RC airplane teaser
Simple Delta Wing
Simple RC plane - no moving control surface at all
RC Airplane For Beginners
[Tutorial] How to make RC Airplane Supper mini - v2
3D PRINTED RC ROCKET CHALLENGE w. JAMES BRUTON | PT.1
Online calc of the CG of an RC airplane