ORIGINAL: jldecarlo
The tank is very small. I would guess no more than 12 oz. There is a molded tray for the round tank, and substitution would be difficult. I know gas engines are more fuel-efficient, but a long flight time seems unlikely.
Leonard
For what its worth. I fly mine with the stock fuel tank, and have my timer set at 12 minutes. I always land with spare fuel in the tank. My flight profile is typically 3D, and heavy on the throttle. I had the same thoughts that the fuel tank wouldn't be enough, but I am pleasantly surprised with 12 minutes each flight.