RE: Futaba R6014FS Recevier
For what it's worth. Servos operate on the length of the pulse, not the voltage. Any reasonable voltage output of the receiver should be sufficient. If you plug your servos into your receiver and they operate properly on the ground, they should do fine in the air.
I think it's a given that Futaba would not put out a receiver that would not be backward compatible with servos used by other Futaba radios. Thousands of us have been interchanging Hitec, Futaba, and JR servos for years.
I have the 12FG with the 6014 receiver driving Hitec 5645's without any problems.