I fill up my Hangar 9, rip around for 10 minutes which is about as much as I can stand, land and have half a tank left, If you can track down that tank size you might be in the ball park.
The problem with asking Horizon is you might get a guy that knows one thing and get a dissertation back on RC cars or whatever he's into but if you ask a Saito question he looks in the manual. Versus catching the guy that actually flys giant scale and might give you a better answer.