About a year ago, 3D Flyer Magazine, did some testing on actual range of the top end radios out there. Futaba, JR, Multiplex, Airtonics and Hitec were the test subjects.

The coordinates of the TX were marked on a waypoint on a GPS unit. The receiver and servos were taken "along for the ride" in a car with the GPS receiver measuring the "straight line" distance.

Most of the radios were still operational at about 2 1/4 miles. JR took the top spot at 3 miles. the rest of them faded between the 2 1/4 miles and 3 miles of range.

So as mentioned before, if you have a pretty good set-up, you will loose sight of the heli, before you loose control.

Rafael