Jinwoo,

I have had both and I can tell you the OS 1.60 uses quite a bit less fuel than the saito 180. I really don't have definate fuel consumption numbers for you, but I would guess the saito uses about 25% more. I am not sure what size tank this plane comes with, but I can fly for about 10 minutes and land with at least 1/4 tank left with my OS. Hope this helps.