RC Helis or otherwise known as Radio Controlled Helicopters are model aircrafts, which vary from RC airplanes in terms of their construction, aerodynamics, and flight training. Common basic designs of RC helicopters are available in the market. Some of which are more maneuverable than other models. Examples of these models that are easy to pilot are those with collective pitch, which mean that their rotor blades rotate on a longitudinal axis to vary or reverse lift.
Flight controls for these helicopter models enable the pilot to control the collective and throttle, which are usually linked to each other; the cyclic controls or the pitch and roll; and the tail rotor or yaw. These individual parts need to be controlled all at once to mimic the movements of real-size helicopters such as hovering, flying forward, and flying backward.
Helicopter models run on servo motors or servos. Plus, a piezoelectric gyroscope is attached to the tail rotor control to deal with wind- and torque-reaction-induced tail movement. You need take note that the gyro does not produce or apply mechanical force. Instead, it electronically adjusts the control signal to the tail rotor servo.
These helicopters are also fitted with radios. For small fixed-pitch helicopters, a 4-channel radio, which includes a throttle elevator, aileron, and rudder, is needed. However, a 2-channel infrared may also be used. On the other hand, collective-pitch models require a minimum of 5 channels with 6 being most common. These include the throttle, collective pitch, elevator, aileron, rudder, and gyro gain. Because of the normal interaction of the various control mechanisms, advanced radios include adjustable mixing functions, such as throttle/collective and throttle/rudder. Radios emit the FM signal in two types of modulation namely Pulse Code Modulation and Pulse-position modulation. Radio prices range from $100 to $2,000. Among the popular manufacturers of helicopter-specific radio controllers include: JR, Spektrum, Futaba, Hitec, Sanwa, and Multiplex.