EBACE Convention News

GE's New Turboprop Engine Family Has Deep Roots in Europe

 - May 19, 2017, 4:10 PM
With modern advanced technology gleaned, in part, from its turbofan development, GE believes its H Series of turboprops represent a giant step forward. Among its features are integrated propeller pitch, better fuel burn/temperatures and variable geometry.

GE Aviation’s new Advanced Turboprop (ATP) to power Textron’s Cessna Denali single will be manufactured at a brand new facility just outside the Czech capital Prague. The new 1,240-shp engine is due to run for the first time towards the end of this year, marking a key milestone in the U.S. group’s longstanding plan to make Europe an important hub for its ambitions in the business and general aviation market.

The $4.5 million Denali, which is due to make its first flight in 2018, will seat six to nine passengers on trips of up to around 1,600 nm and offer a maximum cruise speed of 285 knots. Its engine will have an initial time-between-overhaul of 4,000 hours and is mated to McCauley’s new 105-inch-diameter, five-blade constant-speed propeller.

One of GE’s first moves in establishing its business and general aviation division almost 10 years ago was to acquire Czech engine maker Walter. In the process, it bought the rights to the M601 turboprop engine, which had been newly type certificated by the European Aviation Safety Agency. This was to form the bedrock for a plan to develop the new H Series of turboprops, which powers aircraft such as the Czech-built Let L-410. That, in turn, laid the groundwork for the ATP development.

“GE did not have a large presence in the [business and general aviation] segment at the time and we wanted to leverage the technology and infrastructure that we have on commercial engines and apply it to this sector,” explained Brad Mottier, GE’s vice president and general manager for business and general aviation & integrated systems. By applying some 3D aerodynamic technology and advanced materials it made the step forward to the H Series, and this path will be further advanced for the ATP.

The ATP will have the highest power-to-weight ratio in its class, according to GE, and will have a 33 percent longer time between overhaul (TBO) and 20 percent lower mission fuel burn than equivalent PT6 turboprop engines from Pratt & Whitney Canada (plus 10 percent more power at altitude). GE Aviation is investing $1 billion on the program in Europe, and has more than 400 engineers in Italy, Germany, Poland and the Czech Republic working on it.

Mottier explained that the ATP will incorporate advanced features proven in other GE engines, including variable stator vanes and cooled turbine blades. Additionally, sensors in the engine will gather data that could enable GE to extend the TBO—the engine requires no hot section inspections—and even create individualized maintenance programs for the engines, based on where and how they’re operated.

Initially rated at 1,300 shp, future iterations of the ATP will be rated from 850 to 1,650 shp, and other power range variants will likely be developed in the future. The first engine is expected to complete certification in 2020.

The Czech facility’s established production and repair station certification make it solid foundation for GE’s latest expansion into the business and general aviation market. The site, which employs some 600 people, is already overhauling M601 engines and will eventually support the H Series, too, once these require overhaul (the first units having been delivered in 2013).

Around 150 staff are now focused on preparations for the ATP, such as installing test cells. GE is building a new and separate site to house ATP production, and this will become the group’s worldwide turboprop center of excellence.

“We’re about a year ahead with the development work for the ATP, and the reason for that is the use of additive technology [aka 3D printing] in the engine that meant we could run the combustor as a full-size unit about 15 months earlier than normal,” Mottier explained.

“Effectively, it is 30 years since the last clean-sheet turboprop design,” he argued, pointing to Honeywell’s TPE331 powerplant and the fact that the PT6 architecture goes back to 1964. “With its integrated propeller pitch and speed, improved fuel burn and temperatures, variable geometry and bleed valves, it is truly a modern engine, and is the sum of many technologies already well proven by GE.”

The acquisition of Walter is not the first time in recent history that GE has put down roots in Europe to expand its capabilities. In 2007, it acquired UK-based aircraft components and systems group Smiths Aerospace and in the process added Dowty Propellers to its portfolio. Dowty developed the advanced propellers used for the latest versions of the C130J military transport, including electronic controls. GE is now investing in a brand new facility for Dowty.

More recent GE investments in Europe include a combined spend of around $1.5 billion to buy additive manufacturing specialists Concept Laser of Germany and Sweden’s Arcam. The group is expanding the Germany subsidiary with a $100 million development.

When the business and general aviation division was formed, GE placed a renewed emphasis on customer support for this market segment, including for engines such as the CF34-B turbofan that powers Bombardier’s Challenger 605 jet. “At the time, the product support for business jet engines was being provided by GE’s commercial aircraft group, and there was room for improvement,” said Mottier. “So we reworked the way we provide support, and now we’re number one in the AIN [engines product support] survey. We have integrated turboprop and turbofan product support and also now have a joint venture with Honda Aircraft [for the HondaJet’s HF120 engine, in which GE is a 50:50 partner].”

Passport to Success

Meanwhile, GE’s new Passport turbofan is busily engaged in the flight test program for Bombardier’s new Global 7000 aircraft. In late March, one of the test aircraft opened up the speed envelope to Mach 0.995, just short of the sound barrier. The long-range jet made its first flight in November 2016 and is on track to enter service in 2018. “We’re in entry-into-service mode now,” said Mottier.

According to GE, the Passport will deliver an 8 percent improvement in fuel efficiency compared with other engines in its 18,000-pound-thrust class by drawing on technology from the GEnx engines for widebody airliners. Technology from the GP7000 engine has resulted in unprecedentedly low emissions.

The core is derived from that of the latest Leap engines developed for narrowbodied airliners by GE’s CFM International partnership with Safran. Its integrated propulsion system includes a long-duct, mixed-flow, fuselage-mounted nacelle designed to optimize performance and passenger comfort.