The problem when scaling down a full size aircraft is that the tail moment arm scales down in a linear fashion, while the tail surface area scales down in an inverse square fashion. If you make a 1/4 scale model, the tail moment is 1/4 that of the original, while the tail surface area is 1/16 that of the original. Add to that the change in Reynolds number, and the effectiveness of the tail surface is further reduced. The scale model typically will not have near the GG range of the original, nor the stability.
Roger