World Hum -- Pratt & Whitney has designed an airplane engine they say will about half as noisy, far more fuel-efficient and less polluting than traditional engines, The Economist reports. The PurePower PW100G is a geared turbofan engine that uses a gearbox instead of a shaft between the fan and the turbine used in traditional engines. The engine performed well in an Airbus A340 for more than 75 hours of tests and by 2013 is expected to power two new aircraft being built by Mitsubishi and Bombardier.
