New jet engine uses radical gearbox

The Economist : Europe’s latest economical airliner, the Airbus A320neo, has the option of being fitted with a geared turbofan engine from Pratt & Whitney. Although turboprop aircraft have had gearboxes in their engines for years, no turbofan jet airliner has been fitted with one due to the high amount of power produced by the engine, the lack of materials that could withstand the stress on the gearbox, and the high risk of catastrophic failure. Under the new design, which took 20 years to perfect, the engine’s inlet fan is connected to the compressor and turbine through a gearbox. This gearbox lets the fan turn more slowly than the compressor and the turbine, which means the fan can be made bigger and can thus accelerate a greater volume of air without slowing everything else down. The end result is a quieter engine that can provide longer range and 15% greater efficiency than conventional designs.