A process by which a helicopter can land without power by forcing air through the collective pitch rotor disc, allowing the rotor blades to continue turning.  The pitch of the spinning blades is adjusted when close to the ground temporarily … Continue reading


Angular Vector Control System.  Typically a heading-hold gyro which maintains the helicopter in the current direction until instructed to change by rudder command from the Tx.  Allows the heli to fly sideways or backwards as well as hold position in … Continue reading


Cyclic/Collective Pitch Mixing — Aileron, Elevator, and Collective are combined to give helicopter swash plate servo commands.  Required for control of most modern RC helicopters that use a flybar.  See also CPPM.

Chop Throttle

A term used by RC helicopter pilots describing rapid reduction of throttle stick setting on the Tx.  A habit often formed with fixed pitch or coaxial helicopters that can destroy fixed pitch helicopters by driving them into the ground


Collective is the angle of the main rotor blades of a heli and is why a collecive pitch helicopter can fly upside down. Helicopters with fixed pitch blades (this includes almost all coaxial helicopters) do not require collective.


Combined Pulse Position Modulation — Allows two functions (cyclic and collective pitch mixing) to drive three servos for the swash plate of a helicopter.  See also CCPM.


CYC1, CYC2, CYC3 describe the OpenTX outputs for CCPM mixing for direct control of servos on the swash plate of a helicopter.  Inputs are Aileron, Elevator, and Collective.

Direct Drive

A type of RC helicopter that uses a separate motor from the main motor to run the tail rotor.  Common for micro RC helicopters; unusual for large RC helicopters.


Maintains constant rotor head speed under changing loads.  Typically becomes effective above a specified throttle setting and used for aggressive flying.  Used in advanced collective pitch RC helicopters.