Innovative Idea 30 Years In The Making

The PurePower Geared Turbofan that is set to enter service by the end of the year has been a long time coming. It has been 30 years since a 28-year-old engineer at Pratt & Whitney came up with the idea to slow the main fan with a geared system to transmit power from the turbine to the fan.

The theory was that a large fan turning slower and moving large volumes of air would be more efficient than the fast-spinning fan common on jet engines. And the theory proved to be right.

But the low-volume compressor and low-pressure turbine are more efficient when they run faster, so engineer Michael McCune and his colleagues at Pratt & Whitney in Hartford, CT set out to solve that problem, according to a report appearing in Bloomberg Business. Geared systems had been used for years on turboprop planes, but scaling them up for use in turbofan engines would be the main challenge.

They've been successful ... after 30 years and an investment of about $10 billion by the company. The result is an engine that burns up to 16 percent less fuel and is 75 percent quieter on the ground, according to Pratt & Whitney.

The long development timeline meant that Pratt & Whitney missed an opportunity to have the geared turbofan engine power some of the newest widebody jets coming on the market today. And the large fan does not allow the engine to fit on Boeing's 737 MAX airplane with the proper ground clearance. But the company has found a market with airlines ordering the A320neo, and is the exclusive engine provider for new narrow body airliners from Bombardier, Embraer, and Mitsubishi, according to the report.

FMI: www.pratt-whitney.com, Full report