Pratt & Whitney diz que PW100G cortará queima de combustível

Pratt & Whitney is planning to achieve additional 5 to 7 percent fuel-burn reductions from its PW1000G geared turbofans by the mid-2020s through the adoption of a higher-technology core for the PW1000G family than the core the engines have now.

Interviewed by AIN at the engine maker’s annual media event on Wednesday at its development, production and testing facility at West Palm Beach in Florida, Pratt & Whitney president Robert Leduc said PW1000G engines could achieve up to 7 percent lower fuel burn if the PW1000G’s core incorporated more advanced technologies than those it has now.

“GE, with the [CFM International] Leap X, used core technology,” to produce the 15 percent lower fuel burn offered by the Leap-1A powering the Airbus A320neo family compared with that offered by CFM’s predecessor A320 engine, the CFM56-5B, said Leduc. Pratt & Whitney opted to used geared turbofan technology instead to produce the 16 percent lower fuel burned by the PW1100G-JM compared with Pratt & Whitney’s predecessor A320 engine, the IAE V2500-A5. However, he added, “We believe there is five to seven percent more improvement by the mid-2020s…if we step up the core technology injection,” to produce a PW1000G core as advanced as that of the Leap program.

While the PW1000G’s existing hybrid-aluminum fan blade design is, claimed Leduc, the most efficient fan blade, because using aluminum allows its airfoil to be very thin and therefore more than 98 percent efficient, the next-generation engines will have higher operating pressure ratios and higher temperatures at the back of the compressor. “So we will need a more efficient compressor to keep the temperature down,” said Leduc. “We’ll need 2 to 3 percent better efficiency than historically.”

Additionally, Leduc predicted that the company will need ceramic matrix composites (CMCs) to make next-generation engines. Although Pratt & Whitney chose not to incorporate CMCs into its initial PW1000G core, it manufactures CMC parts for the F135 engine for Lockheed Martin’s F-35 Joint Strike Fighter. For Pratt & Whitney’s commercial aircraft engines, the company believes CMCs will be ready for production in 5 to 10 years.

Meanwhile, Chris Calio, president of Pratt & Whitney Commercial Engines, confirmed that the company has completed developing improved combustor lining material and an improved carbon air seal for the PW1100G-JM’s Number 3 bearing. Together, distressed carbon air seals and degraded combustor linings have led to approximately 50 premature removals of PW1100G-JM engines from A320neos, most of them operated by Indian carriers GoAir and Indigo. “We completed the full retrofit of [already] fitted engines on about 50 aircraft about three weeks ago,” said Calio. “The full suite of hardware and software fixes is in today’s [new] production PW1100G-JMs.”

Another current PW1100G-JM issue, a combustor “shriek” caused by excessive vibration, has been attributed to issues relating to the regulation of air pressure in the number three bearing seal. Calio explained that it has been solved by new engine control software and an improved carbon air seal.

Pratt & Whitney has incorporated all these fixes in an improved PW1100G-JM combustor designated “CSTARS,” which is now undergoing testing at the company’s System Engineering Development Assembly Engine Center in West Palm Beach. CSTARS is the combustor Pratt &Whitney will use to achieve extended twin engine operations (ETOPS) certification for the PW1100G-JM, which it is targeting for this year’s fourth quarter.

“We remain cautiously optimistic about [achieving] ETOPS in the fourth quarter,” said Calio. “We’re meeting all the performance requirements and the regulatory agencies now have the paperwork” associated with P&W’s ETOPS certification testing. Deliveries of Hawaiian Airlines’ A321neos, planned to begin this year, are dependent on the PW1100G-JM achieving ETOPS certification, because all its services between Hawaii and U.S. mainland destinations are ETOPS operations.