I don't imagine your YS will use any more than my OS 50SX uses, and I find that the 8 ounce tank is more than adequate. I have my timer set at 12 minutes, start it on takeoff, and land after it beeps. This leaves me well over a third of a tank for reserve. Remember, you WON'T be using full throttle for long with this plane. Even if you're one of those that hits full throttle on take off and never touches the throttle until landing, it won't be long as you'll blow the tail off the plane very quickly! :-)