The GP7000 engine for the A380

The GP7000 engine—one of two variants for the A380—got its certification almost ten years ago.

11.2015 | Text: Achim Figgen

Text:
Achim Figgen is a graduate engineer special­izing in aerospace technology and he has writ­ten several books on aviation subjects.

Every now and then, aviation history allows itself to take an ironic turn. Take the GP7200, one of two engine variants offered for the world’s largest commercial airliner. Airbus and the A380 customers really have Boeing to thank for this engine’s existence. Back in the mid-nineties, Boeing began the first of several attempts to bring to market a commercial airplane that was based on the 747-400 but that would carry even more passen­gers. The only problem was that none of the three major engine manu­facturers was in a position to supply a suitable engine for the planned 747-500X and 747-600X super-jumbos—and none of them showed any real interest in de­veloping such an engine.

So as 1995 turned to 1996, GE Aviation, Pratt & Whitney and Boeing started exploring the idea of a joint venture between the two U.S. engine manu­facturers with the aim of producing at least one suitable new engine. In May 1996, the co­oper­ation agreement was signed and work began on a new engine dubbed GP7000.

Although it wasn’t long before the 747-500X/600X project was shelved, the money invested was by no means wasted. In the summer of 1996, Airbus launched its Large Aircraft Division, and two years after that, in May 1998, the Engine Alliance an­nounced plans to develop the GP7200—the “2” is Pratt & Whitney’s designation for Airbus—for the world’s largest commercial airliner, at that time still called the A3XX. The 747-500X/600X engine was to be named GP7100.

Best of both worlds

The GP7200 brought together the best of both worlds: GE Aviation was re­spon­sible for the high-pressure section, which largely followed the design of the 777’s engine, the GE90, with the individual components modified to accommodate the A380’s lower thrust require­ments. Pratt & Whitney also adapted its contribution to the 777, the PW4000, this time giving the hollow titanium fan blades crescent-shaped leading edges rather than straight ones.

Although the Engine Alliance is a joint venture between GE Aviation and Pratt & Whitney, that doesn’t mean that these two companies alone manu­facture the entire engine. On the contrary, a considerable portion of the work was contracted out to other manu­facturers. GE’s long-term French partner Snecma is responsible for supplying the high-pressure compressor, while the low-pressure compressor comes from Techspace Aero in Belgium. But the largest contract package went to MTU Aero Engines. All told, Germany’s leading engine manu­facturer supplies 22.5 percent of the GP7200, handling the develop­ment, production and assembly of the full low-pressure turbine and the turbine center frame as well as production of blisks for the high-pressure turbine.

GP7200 and AIRBUS A380

1_GP7000_Dauerlauftest

An improved GP7200 arrives at MTU Aero Engines in Munich for endurance testing.

1_GP7000_Dauerlauftest

An improved GP7200 arrives at MTU Aero Engines in Munich for endurance testing.

2_GP7000_Einschaufeln

Integration of fan blades before testing.

2_GP7000_Einschaufeln

Integration of fan blades before testing.

500,000 flights and counting

Since the A380’s launch customer, Singapore Airlines, opted for the Trent 900 from competitor Rolls-Royce, the GP7200 had to get in line behind the British engine for certification (December 2004) and commissioning (October 2007). The GP7200 completed its first ground test run in March 2004, and in December that same year, flight tests got under way on the left wing of a GE-owned Boeing 747-100. Around a year later, shortly before the end of 2005, the new engine received certifi­cation from the U.S. Federal Aviation Authority (FAA) and on August 25, 2006, the first mega-Airbus powered by GP7200 engines took off. The time for the GP7200 to prove itself in practice came on August 1, 2008. That was when Emirates, by far the most important customer for the world’s largest com­mercial airliner, carried out the first commercial A380 flight from Dubai to New York. The A380 and the GP7200 proved to be a winning combination: since this engine entered service, over 99.9 percent of the around half a million flights it has powered have taken off on time. The Engine Alliance calculates that, by choosing the GP7200 over its British competitor, airlines could save as much as one million dollars per operational aircraft per year.

Airbus A380 during take-off.

Airbus A380 during take-off.

Airbus A380 during take-off.

Further improvements

To help maintain this edge, the company works con­tinu­ously to improve its products. An upgrade to the high-pressure turbines that was announced in summer 2014 has already been installed in 50 new engines and is available for retro­fitting. The new equipment raises the exhaust gas temperature (EGT) margin by up to 10°C and perform­ance by around half a percent. A new kind of control unit software that is currently undergoing endurance testing at MTU Aero Engines in Munich was designed to lower metal temperatures in the high-pressure turbine by 40°C and reduce fuel consumption during ascent by one percent.

While the Engine Alliance can be satisfied with its engine’s performance, its sales figures are a different story. At present, demand for quad-jet wide­body aircraft—a category that includes the Boeing 747-8 as well as the A380—leaves something to be desired. Never­theless, Wolfgang Hiereth, Director GE Programs at MTU Aero Engines, remains convinced that getting involved with the GP7000 program was the right move. First, he is not inclined to give up on this particular market, and is confident that Airbus will continue to find buyers for the A380. And second, the GP7200 helped open the door for MTU to get involved in the next generation of GE wide­body engines—the contract to develop and manufacture the GP7200’s turbine center frame led to work on the GEnx (787, 747-8) and the GE9X (Boeing 777-8X and -9X). And of course MTU Maintenance also benefits from contracts and from the expertise it gains from main­taining wide­body engines.

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