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Integrated Nacelle Systems Take Flight On Global 7000 and C919

 - June 14, 2017, 12:00 PM
Nexcelle's O-Duct thrust reverser design has found its first application with the CFM International Leap 1C engines that power Comac's C919 narrowbody airliner. [Photo: Safran]

The past 12 months have been both busy and rewarding for Nexcelle, which has seen two of its advanced integrated nacelle systems make progress toward service entry. First, in November 2016, Bombardier’s new Global 7000 business jet achieved its first flight, powered by the GE Aviation Passport engine with Nexcelle’s nacelle and thrust reverser. Then, last month, China’s Comac's C919 narrowbody airliner flew for the first time, powered by the CFM International Leap 1C turbofan, featuring Nexcelle’s nacelle and O-Duct thrust reverser.

The joint venture between GE’s Middle River Aircraft Systems division and its French engine-making partner Safran was created with the goal of delivering more operationally efficient and aerodynamically optimized propulsion systems that will result in lower fuel and maintenance costs. “We are now executing on this vision by building the first of our new nacelles, and shipping products,” Nexcelle president Kenneth Onderko told AIN.

Three Global 7000 engines are involved in flight tests now, and Bombardier is set to get Passport engines to power two more test aircraft as it prepares to complete type certification in 2018. The new model’s first flight saw the full deployment of the thrust reversers, which Nexcelle views as a vote of confidence in the system.

We’re delivering assets for these now, and then transitioning to production. For the second half of this year we’ll be focused on the production ramp up,” said Onderko. “The steps and gaps and weight requirements [aerodynamic clearances for the nacelles and thrust reverser] are second to none. This is like nothing we’ve ever done before, and the reaction of the flight team at Bombardier has been very positive. It’s been very robust straight out of the box.”

At the same time, Nexcelle has an engineering team in China to support Comac, which Onderko said would soon resume flight testing after the initial maiden flight of the C919. Formed in 2008, Nexcelle won the contract from Comac in 2010 to develop what it says is the industry’s first fully integrated propulsion system for the Leap 1C—comprising nacelles, thrust reverser and exhaust system.

The design features Nexcelle’s new translating O-Duct thrust reverser configuration, as well as a fan cowl that is structurally integrated with the engine. It also has an integrated mounting system for reducing engine distortion and enhancing on-wing performance. The O-Duct deployment is performed with an evolved electrical thrust reverser actuation system that replaces heavier hydraulic technology, greatly simplifying maintenance. The reverser for the Passport engine, for example, has just two actuators.

The O-Duct design replaces the traditional two-piece “D” doors on the thrust reversers. When the reversers are deployed, the O-Duct eliminates drag links in the engine’s secondary flow part, improving airflow and reducing fuel consumption in the process as well as boosting the overall efficiency of the equipment, according to Nexcelle.

Future potential applications of Nexcelle’s technology will very much be driven by the programs that its parent companies GE and Safran pursue. “The technology can definitely be applied to other new engines,” concluded Onderko. “But this year, all of our focus is on delivering what we committed to [for Bombardier and Comac], and that means certification for both programs and production ramp up for the Passport [engine].

June 2017
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