Internet Tips:

1. The motor thrust line must be a parallel to the bottom surface of the wing or a few degrees negative. This requires modifying the motor installation. (The unmodified mounting will cause a positive thrust line.)

2. Moving the CG forward from the point specified on the plans. The consensus is the CG should be between 7 3/8 & 7 1/2 inches measured back fhom the nose of the aircraft.

The original setup (positive thrust line & rearward CG) can cause the wing to be a handful with a tendency to dive, then zoom & stall from a launch, this has often given the Wild Wing a bad reputation. Correct these things while assembling and you will have a good flying wing when it is set up with proper control throws.
If you keep the wing light a BP 21 motor with a 3s lipo battery will fly it nicely.