Even the best helicopters are loud, rickety gas guzzlers, and a big reason for that is the rotors themselves. As each blade cuts the air, it creates a turbulent wake; the next blade passes through that wake, causing it to shudder and lose efficieny. So NASA invented a shape-shifting blade that stands to make helicopters quieter and more fuel efficient.
The blade has control flaps that resemble those on a wing. But the similaries end there. Embedded with piezoelectric actuators—that is, materials that change shape when jolted with electricity—the surface of the blades flex up and down. By programming the motion of the blades with the right periodicity and amplitude, they can cancel out the vibrations caused by rotor wakes.
This isn't the only shape-shifting wing application out there. Both Boeing and Airbus are researching winglets —those tiny upturned tips on aircraft wings—that will shape-shift slightly during flight.
You can watch video of the blades in action here