Fitting the supplied tank was not an option for me, I wanted a bigger tank (750ml) for some time in the air. I made a cradel for the tank to sit above the retract servo with a quick release catch .The tank then sits higher and improves fuel flow for starting . I tried the standard Thunder Tiger set up and it didnt do it for me. Pulling the fuel up pipes to the engine was a pain , so I fitted a pump from weston models and it worked. Flight time flat out with a TT91 Pro was approx 7 minutes with the stock fuel tank . She runs for 15 minutes easy with plenty left ,I reckon about 18 to 20 minutes flight time can be achieved ,but I find 15 minutes is just right with a comfort zone.