Huge wheels mostly for safety and for convenience. Idea, that typical landing strip is ideal road, perfectly flat and clear from garbage, like stones, but not

Huge wheels mostly for safety and for convenience. Idea, that typical landing strip is ideal road, perfectly flat and clear from garbage, like stones, but not for STOL. And from automobiles exists empirical rule - wheel could easy deal with obstacles less than 25% of wheel diameter (some sources say about 10%). STOL specially made for unprepared sites, like agricultural fields or just non-used wasteland, so they could meet stones or grooves, and should safety land in such conditions, and should be convenient for general field procedures. Even happened tries to make STOL with air cushion, or even crawlers, instead of wheel gear. They fly, but was too sophisticated to be economically comparable to just big wheels.