I think this is part of an early 90's experiment into stopping the blades in flight and using the winglets, to enable faster flight.
Miniature thrusters were placed on the winglets to increase forward speed and operated just prior to a retreating blade stall condition which just happened to be the optimum winglet lift speed (Vo).
If you notice when the aircraft slows down, the airframe begins to rotate. This is because the tail rotor is kept engaged for yaw control, and is more effective at the slower air speeds. Once a boundary speed (Vrt) is reached without the rotors engaged, the TRT causes a virtually uncontrollable spin.
The movement of the blades that can be seen, is caused by the secondary rotor brake creeping. It is a very weak brake and is brought into operation only once when the blades haved stopped (Vrs). This weakness in brakeability is to facilitate a rapide re-engagement.
Unfortunately the experiments were halted due to the increasing loss of aircraft, as when trying to revert to normal rotary flight, 3 aircraft were lost.
This was due to;
i. early re-engagement of the rotors causing blade loss,
ii. too late re-engagement of the rotors causing lift loss,
iii. thruster failure and failure of rapid re-engagement system.
At least the ejection system temporarily developed at the time for the Hind, using Havok design, proved to be a success.
