Pratt & Whitney, CFM Dispute Heat Claims Ahead of A320neo First Flight

 - February 21, 2014, 12:12 PM
A Leap-1A completed early icing tests last month in Winnipeg, Canada.

As CFM International and Pratt & Whitney progress toward the entry into service of their competing engines on the Airbus A320neo, the rival powerplant makers are at odds over which engine will deliver the best performance in terms of turbine temperatures.

The PurePower PW1100G-JM will enter service meeting its fuel-efficiency target, according to Dave Brantner, president of Pratt & Whitney Commercial Engines. Such certainty is unusual at this stage of a program, he said. The geared turbofan promises a 16-percent fuel-burn improvement over current-generation engines.

For the Airbus application, “certification testing is well under way and flight-test engines for the A320neo are being built,” Brantner said. A PW1100G-JM will conduct a third test flight on Pratt’s flying testbed before compliance engines fly on an A320neo in the third quarter. The PW1100G-JM serves as the lead engine on the aircraft, expected to enter service in the second half of next year.

CFM’s Leap-1A will fly on an A320neo approximately one year later. Before that, it will have flown on a Boeing 747 flying testbed starting this fall. CFM and Pratt & Whitney each aim for certification just before their engines’ respective first flights on the A320neo.

CFM executive vice president Chaker Chahrour predicted the Leap-1A will reveal a 1-percent fuel-burn advantage over its rival upon the A320neo’s entry into service. It should add another 1 percent, thanks to the lower deterioration rate integrated between shop visits, Chahrour asserted. He added the Leap engine will offer an extra 1-percent advantage on longer-range missions, such as those served by the A321neo.

The designers of the Pratt & Whitney turbofan claim that its turbine operating temperatures are cooler than those of its rival, thanks to higher propulsive efficiency in the front part of a geared turbofan. As a result, they say, their engine can use simpler, conventional materials.

However, CFM’s Chahrour maintains that Leap high-pressure turbine (HPT) blades will see cooler temperatures. The quest for better efficiency implies more heat but, thanks to its coating and air-cooling system, a Leap HPT first-stage blade will not run as hot as a similar part on the PW1100G-JM, he said. He concluded that CFM uses the same nickel-based alloy in the Leap HPT blades as it does in the CFM56.