Rolls-Royce sets new record with UltraFan power gearbox

Rolls-Royce is testing – and breaking records – with the world’s most powerful aerospace gearbox.

Rolls-Royce

The company announced on September 4, 2017 that the Power Gearbox, which is designed to be used in its next generation UltraFan engine, reached a record-breaking 70,000 horsepower while being tested at its facility in Dahlewitz near Berlin in Germany.

The Power Gearbox, which began testing in May, is designed to run up to 100,000 horsepower, and will be capable of managing the equivalent power of 400 family cars at full throttle.

Each pair of teeth on the gearbox will transmit the same power as an entire Formula One race grid, according to Phil Curnock, chief engineer for civil aerospace future programmes at Rolls-Royce.

The UltraFan engine, which is due to be available for service by around 2025, is designed to be more fuel efficient, and generate lower emissions.

The Power Gearbox, which consists of a series of five planetary gears, will allow the shafts at the core of the engine to run at very high speeds, while the fan at the front runs at a slower speed, said Curnock.

“The engine has a very high speed, efficient intermediate turbine at the back, but if I connected that directly to the fan at the front, it would be spinning too fast, so we need to reduce the speed of that spool, and we do that using the Power Gearbox,” he said. “The Power Gearbox for UltraFan enables a larger, slower, more efficient fan system.”

Rolls-Royce

The engine should be 25 per cent more fuel efficient than the first generation Roll-Royce Trent engines, the company says.

To test the gearbox, Rolls-Royce has built a €84m facility that contains a power test rig and an attitude test rig. The latter, which began testing in September 2016, is capable of tipping and turning the gearbox, to emulate flight conditions, particularly those during take-off and banking.

This allows the team to understand the flow of oil within the gearbox during flight, which is critical for removing heat from the gear teeth, said Curnock. “When you tip the gearbox around it can affect the flow of heat and the flow of oil, so we really need to understand that,” he said.

The power rig allows the gearbox to be tested under the very high power conditions it would experience during take-off, and has the capacity to reach 100,000 shaft horsepower.

The team also plan to begin testing its reliability and endurance.

The company is working with German firm Liebherr-Aerospace, through their joint venture Aerospace Transmission Technologies, to develop its manufacturing capability and capacity for the gearbox.

An UltraFan app, which is free for Apple and Android tablets, has been developed to let aviation enthusiasts and industry professionals get an entirely new view of the engine.

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