Pratt & Whitney’s Geared Turbofan (GTF) demonstrator engine has completed Phase II ground tests and has been cleared for flight testing. Test results show more than 12 percent reduction in fuel burn. There is also a corresponding reduction in carbon emissions amounting to 3,000 fewer tons of CO2 per aircraft per year, along with a 50 percent reduction in NOx and 50 percent in engine noise, some 20 dB below recently introduced noise requirements. The company also claims the new engine will result in double-digit reductions in overall operating costs equal to more than $1.5 million in cost savings per aircraft, per year. The International Air Transport Association says cutting just one minute from every commercial flight would save more than 1.9 million tons of fuel and 6.3 million tons of CO2 annually.
The engine, expected on the market in 2013, will power the Mitsubishi Regional Jet and the Bombardier CSeries. Were it to be installed on existing airplanes, the engine would reduce the amount of fuel burned by 12 to 15 percent, saving on average 215 gallons of fuel each flight, according to Pratt & Whitney.
“The ground test program has been a complete success and the Geared Turbofan engine has met or exceeded all performance targets. This demonstrator engine has confirmed the laboratory results of our Fan Drive Gear System demonstrating excellent efficiency and operational characteristics.”
“The double-digit reductions in fuel burn, engine noise, environmental emissions and operating costs we’ve targeted make the Geared Turbofan engine the best solution for the next generation of commercial aircraft,” said Bob Saia, vice president, Next Generation Product Family.
The two-decade development process has yielded an engine apart from current jet engines, according to Pratt & Whitney. Pratt says current technology, takes air into the combustion chamber, where it is compressed, mixed with fuel, and ignited before being blown through a turbine, to generate thrust, is inefficient because the fan is connected to the engine and turns at the same speed as the turbine, despite the fact fans work best at low speed, contrary to turbine’s optimal performance at high speed. While detractors say that Pratt & Whitney’s introduction of a gear box complicates cost and maintenance equations, the tool allows the fan and turbine to spin independently. The larger fan spins at one-third turbine speed, making for a quieter, more powerful machine which requires less fuel, emits fewer emissions and costs 30 percent less to maintain.
"For the next generation of single-aisle aircraft, there's no question that engine performance will be key," Alan Epstein, the company's VP of Technology and Environment. "Both economically and environmentally, this engine will deliver significant benefits," he added.