Rolls-Royce has started power runs of the gearbox for its future UltraFan engine design. UltraFan, which will be available from 2025, aims to offer a 25% fuel efficiency improvement over the first generation of Rolls-Royce Trent engines, with power scalable for widebody or narrowbody aircraft.

The gearbox is a key component of the UltraFan design, which will be the UK firm’s first geared engine design. In geared engines, like the Pratt & Whitney PurePower family, a power gearbox between the fan and intermediate pressure compressor allows the fan to run at a different speed from the compressor.

UltraFan is being designed to offer efficient power over a wide range of thrust levels and the ability to drive larger fan sizes, while also reducing weight.

The tests are taking place at the Rolls-Royce Power Gearbox (PGB) facility in Dahlewitz, Germany, where the gearbox will ultimately run at up to 100,000 horsepower. The tests follow successful runs on an Attitude Rig last year.

Rolls-Royce highlights the following UltraFan features:

• maximum fuel burn efficiency and low emissions through a new engine core architecture,
• reduced weight via a CTi Fan System of carbon/titanium fan blades and a composite casing,
• increased efficiency through advanced ceramic matrix composites that are heat resistant and require less cooling air,
• efficient power for high-bypass ratio engines of the future through a geared design.

Rolls-Royce is working in partnership with Liebherr-Aerospace, through the Aerospace Transmission Technologies joint venture, to develop manufacturing capability and capacity for the new power gearbox. Rolls-Royce leads the design definition and design integration of the power gearbox, as well as testing activities.

Rolls-Royce ran the gearbox for the first time in October 2016.