a variable speed helicopter rotor system and method for operating such a system are provided which allow the helicopter rotor to be operated at an optimal angular velocity in revolutions per minute minimizing the power required to turn the rotor and thereby resulting in helicopter performance efficiency improvements , reduction in noise , and improvements in rotor , helicopter transmission and engine life . the system and method provide for an increase in helicopter endurance and . the system and method also provide a substantial improvement in helicopter performance during take - off , hover and maneuver .