The Airbus A380 is powered by four R.R. Trent 900 engines. This is the largest aero engine the company has ever built, and is also the is also the world’s cleanest large turbofan engine, measured by emissions per pound of thrust. The engine's turbine fan measures 116 inches in diameter. Design features include new generation “swept” fan blades with a scimitar-shaped leading edge for lower noise and greater aerodynamic efficiency.

http://www.rolls-royce.com/civil/products/largeaircraft/trent_900/index.jsp