Pratt & Whitney has verified that a modified cooling flow corrects a potential over-heating problem on an engine for the Airbus A320neo.
A tear-down inspection in December showed that the component redesign on the first block of PW1100G-JM engines worked as expected, says Bob Saia, vice-president of P&W’s next generation products.
The results keep the engine on track for certification later this year, allowing Airbus to begin the flight test campaign of the A320neo in the autumn.
“We’re really pleased,” Saia says. “We’re confident we’ve got the right configuration to meet the requirements for engine certification.”
The component redesign was tested on the last of four Block 1 engines produced for a roughly year-long test campaign that began last May.
Around the same time P&W discovered the issue with the cooling system. To comply with certification rules, P&W ran an engine on the ground beyond extreme limits for temperature and pressure. The components are expected to survive the test and prove the engine will not fail even under extreme circumstances.
However, a small component – an inlet guide vane buried inside the high pressure turbine – showed evidence of damage after the test, raising doubts about P&W’s ability to receive certification.
But P&W redesigned the cooling flow around the part to keep the component from over-heating, Saia says. The modified part was re-inserted into the engine and subjected in November to a stress test: the 150h “triple red-line” check in which the engine runs continuously at maximum fan speed, maximum core speed and maxhimum exhaust gas temperature for more than six days.
Afterwards, “we tore the engine down and the engine looks very, very good”, Saia says.
Increasing cooling requirements can reduce the fuel efficiency of the overall engine. However, P&W says the modification did not have an impact on fuel efficiency.
“We’re telling everybody that every PurePower engine will enter service meeting our fuel commitments,” says David Brantner, president of P&W Commercial engines. “We won’t have to catch up with any kind of improvement programme.”
P&W has now incorporated the design tweaks in a second block of four flight test engines. The first two engines in the Block 2 configuration are already in test, and the last two are in the final stages of assembly, Saia says.
P&W has always described the engine certification programme for the PW1100G-JM as a roughly year-long effort. Although the flight testing began last May, P&W is not willing to be specific about the timing for the first delivery to Airbus.
The first PW1100G-JM will instead be delivered in the “latter half” of this year, Saia says. P&W is meeting with Airbus later this week to review the schedule, which currently calls for the A320neo to begin flight testing in the autumn.
Source: Cirium Dashboard
