FLUG REVUE February 2004: GP7200 to go to test soon

GP7200 TESTS TO BEGIN SOON

By Patrick Hoeveler

The suspense is rising. Like the maiden flight of a new aircraft, the first full engine test of an engine is always exciting, even if these days the refinements of computer-aided development rule out any major surprises. And indeed, programme manager Bruce Hughes is not expecting any problems on the test run of the Engine Alliance GP7200 planned for 16 February. The goals that the joint company of GE Aircraft Engines and Pratt & Whitney has set itself are truly ambitious: specific fuel consumption by the powerplant for the Airbus A380 is required to be ten percent lower.

GP7200

Whether the engine meets this target will become apparent in the course of the test programme that begins this spring. FAR 33 certification is planned for July 2005, while the in-service date that the engineers are aiming for is October 2006. In the meantime, the first parts produced by Engine Alliance's European systems partners, such as the high-pressure compressor from Snecma and the low-pressure turbine from MTU Aero Engines GmbH, have arrived in the USA. The core engine, which is largely based on the GE90-115B and for which GE is responsible, will be assembled in mid-January and will then be sent on to Pratt & Whitney in East Hartford, where the green run will also take place. Testing in the altitude test facility at Tullahoma, Tennessee, is scheduled to then take place in the mid-March, with the first GP7200 to be taken apart and inspected in May.

The second out of a total of eight development engines is expected to be running in April. Before the end of the year, seven engines should be in action, with the eighth following early in 2005. According to the present plans, trials on the open-air test stands, first in Peebles, Ohio and then in West Palm Beach, Florida, will commence in May. Then in September this product, which is unique in being jointly developed by the big US rivals, will take to the air for the first time on GE's flying testbed, a Boeing 747.

Altogether, the Engine Alliance has committed itself to between 17,000 and 20,000 flight cycles up to certification, more than on the GE90 and PW4000 Extended Twin Operations (ETOPS) programmes. Given the high number of passengers that the A380 will carry, “we really want maturity of this product when it enters service,” says Hughes. As well as safety, reliability is likely to play an important role too. After all, no airline will want to pay for alternative connections or hotel rooms for 555 passengers if a flight has to be cancelled due to engine problems.

To meet the planned in-service date, a lot of component testing has been carried out in advance. These technology maturation tests are now largely completed. The only one remaining is the horizontal containment test of the fan, scheduled for February, in which a loose blade is simulated. The first engine to test (FETT) will incorporate the third configuration of the core engine. Hughes explains, “By tweaking the 3D aero design of the airfoils we increased the efficiency by half a percent, compared to the second core test.”

Altogether the company is planning three versions of the GP7200 of which the total development costs are estimated to be around one billion dollars. To allow some leeway for A380 versions with a takeoff weight of 620 tonnes, the engine will be certificated at a rating of 363kN. The only difference between the various variants is a data plug which defines the thrust performance. According to Hughes, the engine has a potential of up to 374kN. However, if this was implemented, there would have to be changes in the hot section and also additional cooling in the turbines. Again, the noise issue would have to be addressed. But in fact it is likely to be another ten to fifteen years before there is a requirement for such a development.

The GP7200 could actually deliver even more power, but then it would need a larger fan and additional noise reduction technology. This would then take it into the thrust bracket of the GE90 and PW4000, but the Engine Alliance is not planning for a possible successor to these engines. “We will remain a stand-alone product.”

Development of the GP7200 is almost a year behind the rival Trent 900 from Rolls-Royce. Although the American product is currently ahead in terms of numbers ordered, thanks to the recent major order from Emirates for a further 99 units, the Engine Alliance reckons that the market will eventually settle down to a stalemate. After all, there is a “lively competition” between the two camps, as Bruce Hughes puts it. On the topic of price discounts he adds that they were “acceptable on all our business cases.” Thus, the outcomes of the still undecided engine competitions at Qatar (decision expected possibly this spring), Malaysian (mid-2004) and Korean (end of the year) are awaited with suspense. Even though Korean's fleet is powered almost exclusively by CFM and Pratt & Whitney products, Hughes does not believe that the GP7200 necessarily has the upper hand as regards the Korean decision, as the airlines offer a level playing field to the new products.

Given a possible service life of half a century, even for the new engine one can expect the first update programme within eight to ten years. Noise and emissions are likely to be major elements here, Hughes believes. It is possible that a new combustor could be used (TAPS from CFM or TALON from P&W). On the subject of noise, active noise control is a possibility for the future. At any rate there is a need to take action in this area in the near future, as at present the Alliance cannot guarantee to Airbus that the freighter version of the A380 will satisfy the QC2 noise limits at London Heathrow. To meet this requirement, the engineers are investigating the possibility of chevron nozzles, although it would only be worth using them on variants with higher thrust ratings. At present the designers are trying to compensate for the higher fuel consumption.

There are currently no new applications in sight for the GP7200. An enlarged Boeing 747 with a takeoff weight of up to 435 tonnes is still a possibility, but “not very active”. So far there are no twin-engined aircraft prospects, although Hughes believes that, apart from the 7E7, this is could be feasible with appropriate agreement from the regulatory agencies. “If Airbus or Boeing would ask us, we would be happy to discuss it.”

From FLUG REVUE 2/2004

Last updated 10 January 2004

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