The Pratt & Whitney GTF geared turbofan demonstrator engine will have its maiden flight in July on Pratt & Whitney's Boeing 747SP flying testbed, ahead of the trials on Airbus's A340-600 development aircraft later this year.

Bob Saia, P&W vice-president next-generation product family, says the engine manufacturer has been secretly working closely with Airbus on the GTF "for quite some time to look at how we can better integrate engines and nacelles with the aircraft systems". Ahead of the A340 test, "we will fly around 50h on the 747 out of Plattsburg, New York to ensure that we have all the correct laws for the engine controls. Then around 75-100h of flight testing will be undertaken on the A340 during the fourth quarter."

The GTF will replace the Rolls-Royce Trent 500 in the No 3 position on the A340, and will be operated to a maximum thrust of 30,000lb (134kN). "Instrumentation will record temperature and pressure, and strain gauges will measure the characteristics of the metals," says Saia. "Airbus will take in-flight noise measurements, which we will correlate with our ground-test measurements."

The GTF demonstrator engine, which is the prototype for the "fan-drive gear system and the low [pressure] spool and turbine", has an "80in" [2.03m] diameter fan married to a PW6000 core, says Saia. It began ground testing in November last year to evaluate overall engine characteristics. "We have completed 175h of testing, primarily to evaluate performance, noise and structure technologies."

 © Pratt & Whitney

While the demonstrator's fan diameter is greater than it will be for the production GTF's initial airframe applications, the Bombardier CSeries and Mitsubishi MRJ, Saia says that the prototype's fan size is "very appropriate" to that likely to be adopted for any next-generation A320 family GTF development.

The first "full-up GTF" with the definitive core is due to begin testing in the fourth quarter of next year, says Saia. "This will be the engine that we have sold to Mitsubishi for the MRJ. It will begin flight testing on our 747 sometime in 2010."

The 70- to 90-seat MRJ was launched in March with an order for up to 25 aircraft from All Nippon Airways. Deliveries are due to begin in late 2013/early 2014.

The GTF demonstrator began ground testing in November last year

Source: Flight International