Most are a bit deceptive in what they are referring to, 2 ch has a counter balance on the tail rotor that works as a gyro and you have no tail control, the only controls you have are for/aft and left/right cyclic and throttle/collective are not considered a channel because they are on an ECS for the electric helis (wiht fixed pitch) or fixed throttle like on the LMH (unless you use the exhaust control but thats a different story and another ch).

a 3 ch has direct input to tail control

kc