If you stay at full throttle, they can suck up 24 ounces in about 8 minutes. Learned this from Dominator Racing. But who ever flies WFO with a warbird all the time. Too much chance of flutter. For normal sport flying and to keep the weight down an 18 ounce tank should be enough. If you have room you can mount a 24, but don't have to fill it up to save some flying weight. Good luck!!