The slow V is not much of an airplane at all. Waste of money IMO. it is only 2 channel with throttle controlling the altittude.
With all due respect, I think you have the slo-v mixed up with something else.
Skyfly has a rudder and a single elevator.
Slo-v does not have a rudder but does have two elevators...and the v-tail...so altitude is not only controlled by the throttle.
They both are 3-ch proportional.