A collective step makes it possible to change the inclination of the blades of the main rotor of a helicopter . It is found on real helicopters, but it is optional on RC helicopters (also called RC).
Usefulness of collective
A collective step keeps the engine speed constant. There is only to vary the inclination of the blades to move up or down the helicopter. It’s much more accurate and reliable than fixed-pitchhelicopters .
Radio Controlled Helicopters
There is a collective step on all radio-controlled helicopters whose name ends with “CP”, which means ” Collective Pitch “, or “not collective”. Nowadays, all radio-controlled helicopters are equipped with them. For example, the models of Dragonfly 22 , 35 and 36 have a collective step.