RE: reciever for a futaba t8uaf?
The number of channels between the transmitter and receiver do not have to match. In fact -- most 4 channel beginner radio systems come with 6 or 7 channel receivers.
I have an 8 channel transmitter and have but a few 8 channel receivers. Most of my receivers are 5 channle Hitecs (555) and 7 channel Futabas (127DF).