Schweizer 300 with two tanks = 64 gallons or 242 litres. Burns around 35-40 litres per hour, so you get 6-7 hours endurance - even more if you take it easy. There were some remote cattle stations in OZ that used them for mustering for this reason, not sure if that's still the case. Ferrying them anywhere sucks because they are slow as snot, and with that kind of endurance you don't even have a good excuse to land somewhere and have a break.