Glossary Of Terms

2CH Two Channel control. Typically Throttle and Rudder (yaw).
3CH Three Channel control. Typically Throttle, Rudder and Fore/Aft pitch (elevator).
4CH Four Channel control. Typically Throttle, Rudder, Fore/Aft pitch (elevator) and Left/Right roll (aileron)
4-in-1 Typically used to describe a compact electronic device that combines the radio receiver, BEC (battery eliminator circuit), ESC (Electronic Speed Control) and gyro into one unit.
6CH Six Channel control. Typically Throttle, Rudder, Fore/Aft pitch, Left/Right roll, Collective Blade Pitch and Gyro Porportional control
Aileron Typically a term used in airplanes, it can also describe the Left/Right pitching motion that enables a heli to roll or turn during forward flight.
Altitude Vertical height of the aircraft. Controlled by throttle/lift.
BEC Battery Eliminator Circuit that eliminates the need for a separate battery to supply power to the servos. Voltage is generally adjusted to 5V-6V for the servos.
Blade Pitch The angle of the blade in relation to the air within it moves. Higher blade pitch equates to more lift.
Boom Horizontal beam that extends from the rear of a heli, and supports the tail rotor on a conventional heli. It is essentially cosmetic on a coaxial heli, although it can provide an aerodynamic stabilizing effect with


Canopy A small, lightweight fusealage that covers the front of a heli, leaving the tail and some of the internals exposed.
Channel A single radio path by which user controls are transmitted to the aircraft. The greater number of channels the radio system is capable of transmitting and receiving, the greater control the user will have over the


Coaxial Rotors A Main Rotor arrangement that used two counter-rotating blades that both provide lift, with neutral torque (yaw) due to the cancelling forces of the two blades. A tail rotor is unecessary in this setup.
Collective Blade Control (pitch) Not found on fixed pitch helis, this moves the entire swashplate up or down to change the blade pitch of all blades, thereby increasing or decreasing lift.
Crystal There is a Rx Crystal in the receiver and a Tx Crystal in the transmitter. These must match in order for a transmitter to control a receiver. Some helis with 2.4GHz SST (Spread Spectrum Technology) do not use crystals, but rather utilize a roaming frequency that is automatically controlled by computer.
Cyclic Blade Control (pitch) Push rod servo linkages transmit user input that tilts the outer swashplate, which in turn, tilts the spinning rotor “disc” in the desired direction of flight. “Pitch links” transmit the information ahead of the blade in order to give it enough time to fly up or down in time. As the lift changes around the blades, the heli will tilt towards the side with lower lift.
Cyclic/Collective Pitch Mixing To prevent needing separate Cyclic and Collective control servos, three independent actuators move the swashplate together to both tilt and lift the swashplate up and down in a mixed motion, simplifying the mechanism.
Elevator Typically a term used in airplanes, it can also describe the fore/aft pitching motion that enables a heli to fly forward or backwards.
ESC (Electronic Speed Control) Modulates the rotational speed of the motor(s), depending on throttle input from the transmitter.
Fixed Pitch A main rotor blade that has a constant blade pitch. Throttle is used to control lift.
Flybar A rotating weighted shaft that is oriented at an angle to the main blades that uses gyroscopic force to stablize the aircraft
Fusealage The main body of the aircraft, typically made of lexan or polycarbonate.
Gyro Used to describe the electronic device that stabilizes the heli by counteracting external and internal forces that would otherwise cause the aircraft to topple, roll, spin and ultimately crash.
Hover A stable flight at constant altitude with no forward/backward flgith and a constand heading.
Main Rotor The primary rotor used to provide lift
Pinion gear Small gear attached to motor output shaft that drives the main (spur) gear which rotates the main blades.
Pitch Links A link that transmits tilt (or pitch) from the swashplate to the blades.
Receiver This receives a signal from the transmitter and sends these user controls to the on board electronics.
Roll This can describe either the left/right or fore/aft pitching motion of an aircraft, but is typically used in reference to Left/Right pitch, or aileron.
RTF Ready To Fly, a kit that includes all components needed to fly, with no additional purchase necessary.
Rudder This is the control that rotates the helicopter about its vertical axis. It is generally found on all helis, allowing the user to spin the helicopter to face another direction without tilting left or right.
Servo Electronic device that uses a small electric motor to rotate a lever (servo horn) to provide linear actuation of the swashplate or throttle (in fuel powered helis)
Skids Landing gear that consists of horizontal ski-like bars that absorb harsh landings.
Stabilizer See Flybar
Swashplate This rotating plate (or pair of plates) transmits flight control from the stationary servos in the fusealage to the rotating blades. For animated description, see:

Swashplate Wiki

Tail Rotor A smaller rotor used on conventional helis to counteract the torque of the main rotors and provide rudder control.
Tail-In An orientation in which the nose of the heli points away from you and the tail points towards you.
TBE Toilet Bowl Effect. A condition caused by an imbalance in the heli that causes it to rotate in a circle, all while maintaining the same heading, swirling around as if it were in a toilet bowl. Most often caused by a bent or improperly adjusted flybar.
Training Landing Gear Long, lightweight rods with impact-resistant balls (typically ping-pong balls) at the ends that extend from the helis skids to help absorb harsh landings that frequently occur during the training stage.
Transmitter Handheld device that transmits user controls to the aircraft.
Trim Fine controls adjacent to each stick on the transmitter that allow the user to “zero out” each control, allowing for a stable hover.

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