RE: 2nd airplane choice after trainer?
To follow-up ,as stated by others , you will need an additional standard servo for most any new plane you get as most use (1) servo for each aileron connected with a "Y" cable for a 4-channel receiver. A standard Futaba servo 3004 is around $15.00 and you could put that on the elevator and use the other servos for the rudder, ailerons, and throttle.