1/5 and 1/4 scale engines run on gasoline, but if you're talking about .12's, and .15's. It probably wouldn't work. And you wouldn't run on straight gas too, because .12's .15's and .21's are all 2 stroke engines, that would require a gas/oil mix. Gas is cheaper, but personally i think a gas engine wouldn't produce as much power or would be that efficient.