Danish company develops bespoke bearing test rig for Rolls-Royce UltraFan engine


Danish company R&D Test systems has developed and supplied the bearing test rig for Rolls-Royce’s UltraFan engine program.

UltraFan is a geared-turbofan engine that uses new materials and a variable pitch fan system to improve fuel efficiency up to 25% compared to Rolls-Royce’s first-generation Trent engine. Ground testing of Ultrafan is expected to happen at Rolls-Royce’s Testbed 80 in Derby, UK next year, despite doubts about whether there is sufficient market demand to progress the engine’s development because of Covid-19.


Artist’s Impression of the UltraFan demonstrator engine (Image: Rolls-Royce)

A key innovation of UltraFan is its Power Gearbox, situated between the fan and compressor.

The bearings are a key part of the Power Gearbox and have to be shown to be capable of operating at the Gearbox’s peak output of 50MW, the the equivalent of 500 family cars.

Testing of the Power Gearbox and the bearings is being conducted at the Rolls-Royce facility in Dahlewitz, Germany.

The custom-designed, high-precision test rig for the bearings is capable of simulating extreme operating and environmental conditions and was delivered to Rolls-Royce at the end of last year. The rig offers fast mounting of the components to be tested, multiple high-precision measurements and rapid assembly with a compact, flexible and modular design, said R&D Test systems.

test rig

The core of the bearing test bench

The test rig can measure up to 350 different data points via sensors observing a particular aspect of the bearings. In addition to proximity, load, tilt and temperature sensors, it also incorporates a specially designed hydraulic system to apply precise load.


Test rig diagram

Schematic of the test rig’s load unit

“R&D’s multidisciplinary team of mechanical and software engineers is proud to support Rolls-Royce’s tests on a major component of the completely new Power Gearbox within UltraFan,” said Asger Krogstrup, project manager at R&D Test Systems.

“It has been both an exciting and challenging project taking us to the limits of what is technologically possible. We have had close cooperation with Rolls-Royce from start to finish to ensure the best integration of the test rig into its development work in Germany,” he added.

Test rig

The test rig measured 350 data points

“It is great to see the test rig developed by R&D’s engineers up and running at our facility at Dahlewitz,” commented Holger Klinger, Sub-System Executive at Rolls-Royce. “We have worked on this joint project for more than two years to develop this proving ground for the bearings that will be used in the new Power Gearbox for the UltraFan.”

The rig manages drivetrain speeds of above 5,000rpm and torque levels of above 1,500Nm.

test rig

The outer bearing support structure of the test rig

The test rig can be disassembled and modified for different test campaigns in as little as one to two days, and supports failure-safe installation of a new component for test.

The R&D Test Systems team also custom-designed lubrication units to use contaminants for environmental testing and a test management system, capable of event monitoring and automated fault handling to reduce operator involvement, saving time and increasing both speed and accuracy of the testing.

The new bearing test rig will allow Rolls-Royce to test the performance of this key component under both normal and extreme operating conditions. At the same time, an extensive amount of high-precision data will be collected for subsequent analysis and documentation. This will enable a faster and more iterative development process, as well as continuous testing at several stages during the build phase, making the test rig an important element in the development of these bearings.

R&D Test Systems is a part of MTS Systems Corporation and employs around 200 people at 11 sites around the world.

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Ben has worked as a journalist and editor, covering technology, engineering and industry for the last 20 years. Initially writing about subjects from nuclear submarines to autonomous cars to future design and manufacturing technologies, he was editor of a leading UK-based engineering magazine before becoming editor of Aerospace Testing in 2017.

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