Im going to guess 12,387 ft, 11 in.

The range is farther than you can see the plane. The is in a wide open space with no obstructions of any kind. The lower your plane is to the ground, the less range you will have. That is, a plane 200' high will have a longer range than a plane that is 20' high from the ground.

I know 1st hand the a 2.4 DX7 has a range of a little over 2 miles. Again, with NO obstructions and over 200' high.