Stall turn

From RC Helicopter Wiki

A stall turn appears identical in many respects to a fixed wing aircraft's stall turn.

From forward flight, the helicopter's nose is pulled vertical, and the collective reduced to zero degrees. The helicopter is now propelled upward soley by its forward (now upward) momentum. At the zenith of the stall turn, the rudder is applied to bring the nose around 180 degrees to point directly at the ground, and as the aircraft falls earthwards, elevator and collective are applied to bring the helicopter back into level flight.

A tail slide is identical, except the nose is not brought around and the helicopter exits the stall turn flying backwards.