I have an LED indicator which monitors the Rx battery, a 1700mAHr Ni-Cad. This is installed in a .40 trainer with 4 Futaba 9201 servos (a bit of overkill, but left over from my old heli).

It has 5 green LEDS and 4 red LEDS. After seven 15 minute flights the LED indicator had moved from the 5 LED to the 4 LED. I discharged the Rx battery through my charger/cycler and found I still had approx. 1200mAHr left in the Rx battery.

Therefore I should get about 6 hours from the battery!!!! However I am only doing circuits and the servos are not being moved constantly. Most of the time they are probably stationary.

I do know with my heli, that an 1100mAHr Rx pack will only last for four 15 minute flights. But that does have five 9201 servos and a gyro. With a heli you are constantly moving all the servos, hence the vast difference in current draw and time.

The amount of time will obviously depend on the battery size, but also the type, and number, of servos used and the type of flying you are doing. You will need to monitor the battery to get a feel for how long they will last.

Hope this is useful.

Sarah