You may have heard that Rolls-Royce has partnered with Liebherr Aerospace to help them create a new generation of aircraft engines. If you’re in a land-based business – mining, for instance, you may know Liebherr in an entirely different context. But the German firm manufactures everything from heavy mining equipment to refrigerators to, yes, aerospace components.
For new joint venture with Rolls-Royce, they’ll be producing an “ultrafan” that will make certain aircraft engines 25% more fuel efficient than RR’s first-gen Trent engine. Development is going to take a while — the ultrafan is not expected to be available for another 10 years. When it enters service in 2025, it will be the first geared commercial jet engine to carry the Rolls-Royce name.
Rolls’ Trent engines are currently used in the Airbus A380 superjumbo, A330 wide-body and Boeing’s 777 and 787 aircraft. The company says the new ultrafan will support both wide-body and smaller airliners, thanks to its ability to bridge a wide thrust range.
Before the joint venture was formally announced, some industry insiders had speculated that Rolls-Royce would choose Aero Gearbox International as their partner because that entity is already a joint venture of Rolls and Hispano-Suiza and also because Liebherr has had limited experience with aircraft engine transmission systems.
Nonetheless, Liebherr-Aerospace officials say they are looking forward to the opportunity to “significantly enlarge” their scope of activities. The company manufactures large, multi-stage planetary gearboxes for wind turbines, but Rolls-Royce says they liked Liebherr-Aerospace for the project because of their previous experience making gears for helicopters and their substantial background building gear drive systems for the AE2100 and T56 turboprop planes and lift fans for the F-35 Joint Strike Fighter, according to British sources.
How will the project come together?
Official joint venture headquarters are located in Friedrichshafen, where production engineering will design power and gear drive train components for the ultrafan. Rolls-Royce is leading the design, integration and testing phases and also building a new $90 million test center south of Berlin. Some of that funding is coming from the Brandenburg regional government. They expect testing to begin late next year.
Liebherr will be responsible for component manufacturing – initially at their Friedrichshafen facility, although production could move to a stand-alone facility in the future as production increases.
Rolls-Royce announced last year that they would undertake a two-step design program to upgrade their 3-shaft turbofan architecture to meet new demand for greater thermal efficiency and propulsive capability.
As a result, although the ultrafan will be similar in some ways to Pratt & Whitney’s PW1000G geared turbofan, it will be targeted to the medium- and higher-thrust application markets. The ultrafan is expected to deliver a 15:1 bypass ratio and 70:1 overall pressure ratio, the power combination which will deliver the ultrafan’s 25% fuel efficiency increase.