Yes, I agree a 78" airplane is tiny IMO. Anything I own that small or smaller is electric these days. I started building models in 1963, U-Controls, free flights, and rubber powered Comet kits, a few years later I got into R/C, and a .60 size was considered a very large airplane, but that was long ago. I would say that anything with lets say 100" + wingspan is getting into the giant scale range. I know, IMAA giant scale legal is 80" on a mono and I think it's 25% on a biplane, but the truth is... They are still tiny at those sizes. I guess it is all relative to what you are familiar with flying.
Bob