The Mi-28N Night Hunter day/night version flew in November 1996 and features a radar mounted on the rotor mast
Textron System officials described the 'Air Hummer' as a slowed-rotor compound system, where the blades are heavily weighted at the lips and, after vertical take-off and transition to forward flight at around 150 ft when lift is generated by the wings, the rotor mast
tilts forward to allow the rotor to fold back to reduce drag.
Normally, a helicopter rotates around the CG, and, since the rotor mast
is in line with the CG, you have to be creative to hit yourself with the rotor in-flight.
The hinges and bearings used to attach conventional rotor systems to the rotor mast
and that allow the blades to flex during flight are replaced with elastic, fiberglass-type components.
After the helicopter landed, the helicopter s clutch re-engaged and the main rotor mast
severed just below the rotor head.