Four Channels Defined
In a four-channel helicopter, each channel controls one surface. One channel is used to control the rudder, or the side to side swinging of the body. This is called the yaw. Another channel is used to control altitude, or straight up-and-down flying. The third channel is used to control forward or backwards movement. The fourth channel is used to control side to side movement. In the transmitter, two channels are usually tied to each joystick. Pushing one of the sticks forward and back will move the helicopter forward and back. Moving it from side to side will move the helicopter side to side. The other stick will control the altitude and the yaw. It takes a great deal of skill to coordinate all of your stick movements for a smooth flight. This can only be achieved by practicing over time.
Two Extra Channels Defined
The first four channels are the same as a four-channel helicopter, but the fifth and sixth channels add another attribute to flying. The fifth channel is controlled by moving the control stick up and down. It slides up and down in the transmitter housing. The stick has three movements: Back and forth, side to side and up and down.The fifth channel controls the collective. Collective is the pitch angle of the blades.The sixth channel is more of an optional channel. It can be used to control the on-board gyro or the air/fuel mixture to the engine.
Flying Characteristics
The difference in flying characteristics is that with the extra two channels, highly aerobatic maneuvers are possible. For example loops, both inside and outside, can be done with a six-channel helicopter by controlling the collective. By reversing the collective, the helicopter can literally fly and hover upside down. Also, by controlling the gyro, you can control how fast the turning response time is. This comes with a trade-off, however. If you are not a seasoned pilot, turning the aircraft too fast could flip it, driving it out of control.