The unknown territory is the area near the "cliff". That knee can happen very fast. Typical curves like this show exactly where this would happen, but it differs with each battery pack (slightly) and of course, with different people operating the equipment.

The battery discharge is of course a function of usage of the components. The RX demands a specific amount of current @ a range of voltages to operate. The servo's however, vary their demand on current as useage goes up and down. For each flight, this becomes an average because you won't fly exactly the same way each time, thus the current draw will slightly vary each time you fly.

But, you can figure out your average usage by doing the discharge (via flights) and charge cycle. To do this correctly, of course, you will have to measure your flying time as closely as possible and then add the total times for each flight (remember, flying time starts the instant you turn on your receiver on the bench till the time you power down the receiver). Add all this time up, then when you finish with the cycle charge, read the total current to bring you back up to full charge then calculate your current draw based on time. Do this several times over the course of a couple of weeks, then do an average. This will begin to tell you how long your pack will last and how much current you've used during that time (of course) and then you can work with that to determine your safe flying times.

That's about the best way I can think of to do this. Of course, someone will tell you to put recording equipment on your plane... ok.. that's fine, if you know how, and if you can afford it.

CGr.