In general, lift is controlled by the pitch (angle) of the main rotor blades and the speed at which they move through the air.

On your heli, you have a limited control of the pitch just for moving left and right, forward and back (called cyclic pitch). The pitch that controls the overall lift is fixed and you just control the speed to make the heli go up and down.

On "3D" heli's that can go upside down they have what is called "collective pitch" which means that the pitch of the blades can be controlled together to make the heli go up and down, in addition to the cyclic pitch.

As long as the blades have a positive collective pitch, they hold the heli up in the upright orientation. If you invert the collective pitch, the lift from the blades also inverts and would push a heli down if the heli were upright, but flip the heli upside down and now the blade pitch is holding the heli up in the air

The way they make this work in the control is to link the throttle stick (left stick up and down) to throttle and collective pitch. This requires a computerized radio that lets you program the throttle and collective pitch functions in relation to stick position for different flight modes. In normal flight mode, when the throttle stick is at the bottom, throttle is zero and collective pitch is zero. Mid stick is middle throttle and positive pitch and full stick is full throttle and full positive pitch. In "idle up" mode, the throttle is changed so that max throttle is at both low stick and high stick, with a little dip in the middle and collective pitch goes from negative at low stick, to zero at mid stick, to max positive at high stick.

This programming is done with what is call throttle curve and pitch curve which are graphs that represent the throttle and pitch relative to stick position. The normal throttle curve is just a straight line from 0 throttle on the left to max throttle on the right and looks kind of like this: / The idle up throttle curve looks like a V. The pitch curve is a straight line similar to the normal throttle curve, but in normal mode it starts halfway up on the left side for 0 pitch and in idle up mode it starts all the way down at the bottom left for negative pitch.


That's the basics, the curves may vary a bit for more performance but that's the gist of it.