Pratt & Whitney gears up for PurePower test run

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Pratt & Whitney has reached a milestone in the development of its new geared turbofan engine after completing assembly of the first PW1524G scheduled to power Bombardier's CSeries airliner.

The first of eight test engines will be trucked in September to the company's West Palm Beach, Florida test facility for its initial run, expected to take place later this year.

Successful engine validation should have the GTF flying under the wing of a CSeries in 2012 and in service with Bombardier's 110- to 149-seat CS100 in 2013.

In July, the company completed 260h of core testing, along with "hundreds of hours of testing" of the low- and high-pressure compressor, as well as 60,000 simulated cycles on the fan gear drive system that allows the 188cm (74in) fan to spin at a speed one-third of the engine's low-pressure compressor and turbine. This is key to P&W's expectations that the engine will cut fuel burn by 15% over current-generation powerplants.

gtf nacelle
 © Pratt & Whitney

The process of certificating the first member of P&W's geared fan family will take place over the next 24 months, with the first three engines focused on evaluating the overall architecture of the engine in sea-level test cell environments.

In the second quarter of 2011, engine three will be fitted under the wing of the company's Boeing 747SP test aircraft and flown for a three-month test regime at altitude, evaluating the performance along with trials that include accelerations, decelerations and in-flight starts.

"The first six months are typically driven to validate that the engine works," says Bob Saia, P&W vice-president, next-generation product family. He says heavy certification testing with a fully conforming article for regulatory approval is to begin in mid-2011 and continue over the following 15-18 months.

During the 24 months, P&W expects to submit just under 300 certification reports for airworthiness approval and complete four to five builds of engine one during that period.

Saia says engine six or seven will take part in blade-out testing. This will take place just 10h into the engine's life before it is intentionally destroyed. During that test, one of the engine's bi-metallic, titanium sheathed blades will be thrown while the engine is operating at redline speed, destroying the powerplant, while validating the casing is robust enough to contain the explosive force of the failure.

The heavily instrumented eight test engines, which will measure more than 2,000 parameters, will be assembled at the company's Middletown, Connecticut facility. The first production PW1524G engines rated at 24,000lb-thrust (107kN) that will power the five CS100 flight-test aircraft will either be partially or fully assembled at the company's new Mirabel, Quebec facility, says Saia, "so we can validate the test facility and some of the operational procedures in Mirabel".