Green Technology: Jets Gear up to Fly Greener

Pratt & Whitney's geared turbofan program is set to take to the skies with innovations ranging from reduction gearing to low-emission combustion cycles. Living in an airport flight path? Your skies may soon be quieter and cleaner if aircraft-engine maker has anything to say about it. The company recently finished ground-based testing of its geared turbofan (GTF) concept. The next step is flying the 30,000-lb-thrust engines on a P&W-owned 747SP testbed. Airbus has also agreed to flight-test the engines on one of its own A340s later this year, using the same test program. The prototype engines are said to be around 50% quieter than those they could replace. In addition, P&W expects the engine will cost 30% less to maintain and will be greener than competitors'. The company claims it uses 12% less fuel and cuts emissions by 20%. has already gambled on the design, inking an agreement to purchase 15 Regional Jets carrying the new powerplant, with the option to buy 10 more. Mitsubishi will use a version of the GTF that puts out 14,000 to 17,000 lb of thrust for its smaller planes. also plans to power its CSeries jets, scheduled for sale later this year, with a 23,000-lb version. The Bombardier engine is similar to those needed by medium- duty Boeing 737-300s. Both the Mitsubishi and Bombardier jets should enter service in 2013. The test flights and future orders are the culmination of a 20-year-long development program. Working with MTU Aero Engines, Avio, Volvo Aero, Goodrich Aerostructures , P&W has rethought many of the major systems that make up commercial-jet engines starting with the intake fan and moving aft through the compressor stages, combustor, and turbine stages. Bypass ratio, fan speed, and combustion efficiency are all getting an overhaul under the GTF program. So what is it about