Hey, I'm a computer guy so all I know is the binary system. On and off. The throttle is either full open or at idle!!!

Just kidding of course. What I do with a plane is run it on the ground (tied down and secured) to find out how much time I can run it. Fill the tank, start the engine, and run it at full throttle until the tank runs out and time how long it takes. Doing this will give you a good idea of how long you can fly before running out of fuel. Of course when you fly at less than full throttle it will increase the amount of time you can fly. But (isn't there always a but??? ) on planes that can go 20+ minutes you'll find that more people won't fly that long. Eye fatigue, arms getting tired, etc... set in when you fly for long periods of time. Most pilots find that shorter flights are much better for them. Myself I usually fly for 11 minutes each flight. I have a countdown timer that I use when flying. I set it for 11 minutes and when the time is up the alarm will go off and I know it's time to land. I like using this system because I don't have to look away from my plane to know when it's time to land.

Hope this helps

Ken