NASA is working on smart shape changing helicopter rotors.
Twenty years from now, large rotorcraft could be making short hops between cities such as New York and Washington, carrying as many as 100 passengers at a time in comfort and safety. Routine transportation by rotorcraft could help ease air traffic congestion around the nation's airports.
the SMART Rotor can reduce by half the amount of noise it puts out within the controlled environment of the wind tunnel. The ultimate test of SMART rotor noise reduction capability would come from flight tests on a real helicopter, where the effects of noise that reproduces through the atmosphere and around terrain could be evaluated as well.
The test data also will help future researchers use computers to simulate how differently-shaped SMART Rotors would behave in flight under various conditions of altitude and speed.