A new jet engine from the gearheads at Pratt & Whitney will cut fuel use, emissions, and noise. The advances could be a godsend for airlines trying to make do with spiraling fuel costs.

The secret lies in some clever engineering and a $1 billion gamble by one of the world's leading aircraft engine makers. In current jet engines, the fan is directly connected to the turbine. Turbines are most efficient when spinning very fast, but this forces the fan to turn quickly as well, making that part of the engine inefficient and loud. Creating larger fans to counteract noise cancels out performance gains.

Adding a gearbox to let the fan and turbine rotate at different RPM's has long been assumed to be unworkable, with the extra parts resulting in a heavier, more complex and less reliable design. P&W's breakthrough is a geared turbofan, which integrates a gear box between the fan and turbine so that both can operate optimally while still using the same drive shaft. Lots more geekalicious details are available at Machine Design, if you're interested.

Overall, the improvements could reduce fuel by up to 15%, emissions by 20%, and noise by a whopping 50%. In addition, a less conspicuous motor will allow jets to fly lower and take fewer detours around populated areas, saving yet more gas.

Ground testing of the new system was recently completed and in-flight tests are scheduled for a Boeing 747 and an Airbus A340 this year. The engines are expected to begin entering service around 2013.

Sources: The Globe and Mail and Machine Design