New Jet Engine Incrementally Better

The new Pratt and Whitney geared turbofan is an excellent innovation in gas turbines for jet aircraft. By allowing the compressor to spin at a slower speed than the drive turbine fans, the overall engine system can burn 12 to 15 % less fuel per amount of thrust. In a time of high fuel prices, that level of improvement in efficiency matters.

Current jet engines have fans that suck air into the combustion chamber, where it is compressed, mixed with fuel, and ignited. Then it's blown through a turbine, generating thrust. It works, but it's inefficient because the fan is connected to the engine and turns at the same speed as the turbine. Fans work best at low speed, while turbines work best at high speed.

Pratt & Whitney solved that problem with a gearbox that lets the fan and turbine spin independently. The fan is larger and it spins at one-third the speed of the turbine, creating a quieter, more powerful engine the company says requires less fuel, emits less C02 and costs 30 percent less to maintain. Pratt & Whitney has been torture-testing the engines, and its engineers have simulated more than 40,000 takeoffs and landings. __Wired

A nice incremental improvement, and quite timely. More on the new engine:

...the Geared Turbofan will have operating costs 10% lower than current engines and maintenance costs that are 30% less. According to Pratt & Whitney, that translates into $600,000 $1.5 million in annual cost savings for a 120- to 180-passenger aircraft. __Source

For the airlines that survive the current fuel price peak, this should help.