Pratt & Whitney has developed a jet engine that is significantly cheaper to run, more efficient and less polluting than current engines. The "geared turbofan" engine burns 12 to 15 percent less fuel than other jet engines and cuts carbon dioxide emissions by 1,500 tons per engine per year.
Current jet engines have fans that suck air into the combustion chamber, where it is compressed, mixed with fuel, and ignited. The resulting gas blows through a turbine, generating thrust. This is inefficient because the fan is connected directly to the engine and, so, turns at the same speed as the turbine. But fans work best at low speed, while turbines work best at high speed.
The new Pratt & Whitney engine has a gearbox that lets the fan and turbine spin independently. The fan is larger and spins at one-third the speed of the turbine. This creates a quieter, more powerful engine which uses less fuel, emits less carbon dioxide and costs less to maintain.
"It’s technology like that geared turbofan that’s going to drive fuel efficiency forward for this industry in the short and medium term," says Earnest Arvi of the Arvi Group. "Alternative fuels show great potential, but they’re decades away."
The engine is expected to be in regular service by 2013.