Bear in mind the helicopter rotor system takes about 1000 feet of descent to aerodynamically establish autorotation.
Pardon a question from a low timer but why anything like 1000feet?
Won't an autorotative region of the blade be providing some force just as soon as the underside of the disk of the rotor is presented to the airflow. Ie within a few seconds after pulling aft cyclic to get say from 10degs nose down disk in forward powered flight to 10deg nose up disk while slowing to best auto speed.
Oow