Rolls-Royce has officially opened Testbed 80. Mark Broadbent looks at what it offers and why in this case bigger really is better
Everything about Testbed 80 at Rolls-Royce’s Derby plant is big.
Its internal chamber where turbofans are tested is 7,500m² in area, making it the largest indoor jet engine test facility ever built. The building has 3,128 tonnes of steel and 27,000m³ of concrete, enough to fill 11 Olympic-sized swimming pools. Fittingly, given these big numbers, Testbed 80 will play a big role in Rolls-Royce’s engine-development work. According to CEO Warren East, the facility “features the most advanced testing technology we have ever used” with cutting-edge systems to “test engines to the limit, physically and digitally”.
Testbed 80 is the result of a £90m investment by Rolls-Royce and athree-year construction project.
Although only formally opened in June 2021, the building was completed by the turn of this year and a Trent XWB was test run in the facility in January 2021. The XWB and Rolls-Royce’s other current-production civil aero powerplants such as the Trent 1000 will continue to be tested there as the manufacturer works to improve these powerplants.
However, the main reason for Testbed 80’s development is to support the development of larger, more efficient turbofans.
The company plans to run the first demonstrator UltraFan engine in Testbed 80 early next year, the facility providing the extra capacity Rolls-Royce needs to test this new-generation powerplant as development work ramps up.
Like a cathedral
Rolls-Royce said visitors have likened Testbed 80 to a cathedral, thanks to the feeling of vastness and the massive construction effort required to build it. The size is deliberate. UltraFan will have a 3.55m fan diameter, making it the largest civil aviation turbofan ever (the current largest is the 3.45m GE9X on the Boeing 777X).
Rolls-Royce summed it up: “Modern jet engines are bigger and more powerful than ever before, so we need larger spaces to test them in.” The company promises the UltraFan, which will have a 15:1 bypass ratio, will burn 25% less fuel than the first-generation Trent turbofan.
Beyond being simply a more appropriate facility for larger engines, Rolls-Royce believes Testbed 80 signals a new era for testing. Times have “moved on from the days where engines would be tested for weeks”, the company noted.
Leaps forward in digital design and modelling software mean engineers can now “predict how an engine will behave” at the design stage. So advanced are these engineering capabilities that physical testbeds are now mostly used for verifying the sophisticated design models rather than finding out information, the company says.
Testbed 80’s flagship capability is an extremely powerful X-ray, which, at nine Mega Electron Volts, is 60 times as powerful as an X-ray used to inspect a broken bone.
It enables the manufacturer to X-ray live running jet engines.
Helen Pearce, radiation protection adviser at Rolls-Royce, explained: “During X-ray testing, the facility is no longer a testbed, it becomes an X-ray bunker”.
Although Testbed 80’s solid concrete walls are between 1.3 and 1.7m thick – which Pearce says provides “phenomenal” shielding – there is still a controlled area around the facility and several neighbouring buildings. “No one is allowed within a certain radius of the building, even if they are outside, to ensure nobody can enter,” she noted.
Before any scan begins, supervisors conduct an elaborate safety procedure to ensure nobody is left inside the testbed. Pearce said: “When we conduct static X-rays in a small room, it’s easy to ensure nobody’s there. With a space larger than a Premier League football pitch and with multiple floors, we need to be certain that nobody is inside the radiation zone before we start testing.”
An engineer must find and push 45 buttons – some of which are in areas that are hard to reach, or behind doors – in a specific order within an allocated amount of time. Only when this is completed is a key released that allows them to leave the X-ray zone and secure the facility, certain that nobody is left behind. Highly trained radiation protection supervisors then operate the X-ray machine. The test chamber is capable of testing 155klbf, and the speed of the air exiting the augmenter tube when an engine is under test exceeds 640kph.
Testbed 80 generates a huge amount of data for engineers. The facility can measure more than 10,000 individual parameters on an engine, and around 200,000 samples can be captured in each second of a test run, down to the smallest vibrations. According to Darren O’Neill, Rolls-Royce’s project engineer test capability, its systems record more data in a single day than is held by online encyclopaedia Wikipedia. O’Neill said: “Physical testing confirms what we have already predicted using models. Testbed 80’s advanced systems will capture more data than ever before, improving our understanding even further. By understanding the engine better, we believe engineers could make modifications that deliver improvements in specific fuel consumption, basically how much fuel the engine burns during flight.
Testbed 80 data is sent directly to a secure cloud, where the company’s engineers will analyse the results.
Testbed 80 offers far more than just advanced X-ray facilities providing hugely detailed views of running engines.
With the wider political push, in the West at least, to decarbonise and limit the rise in global temperature to 1.5ºC, there is growing focus across developed economies on attaining ‘net zero’ onCO2 emissions by 2050.
This puts pressure on the aviation industry to rapidly decarbonise, which is increasingly making sustainable aviation fuels (SAF) a prime focus in the wide-ranging efforts to clean up.
While hybrid or fully electric powerplants interest developers for short/medium-haul operations or regional flying, Rolls-Royce said: “The future of medium-to-long-haul flight still needs the gas turbine, but it also requires a new level of environmental performance.”
SAF is a solution, it said, because it offers “net CO2 lifecycle emissions of…at least 75% less than conventional jet fuel”, with the possibility of further reductions as production methods advance in the years ahead.
Testbed 80 will be used to conduct the first ever demonstrator test of a Rolls-Royce engine running on 100% SAF – the type has not been confirmed publicly yet, but is reportedly a Trent 1000. The facility has a tank capable of holding 140,000 litres of fuel of different types, including SAF.
The evaluation will follow SAF tests that Rolls-Royce has recently carried out at its other test facilities in Derby. Last year the company began testing SAFs on a Trent 1000 engine incorporating the ALECSys (Advanced Low Emissions Combustion System), Rolls-Royce refers to as its “lean-burn technology”, and earlier this year announced it had conducted the first tests of 100% SAF in the Pearl 700 engine at its plant in Dahlewitz, Germany.
Speaking during Rolls-Royce’s Q4 2020 earnings call, Warren East said the results from the company’s SAF trials so far “have been extremely promising”. Testbed 80 will give added impetus to the exploration of these technologies.
The CEO said: “We see the use of SAF as vital. And it requires little change to our existing engine architecture – what we're working on with partners in the industry is SAF that can be simply dropped into the engine. The fuels also have higher energy density and fewer impurities. Additionally, they can be created synthetically using captured carbon, with a zero-carbon energy source. That's what gives us our net zero.”
Force for good
Paul Stein, Rolls-Royce chief technology officer, said: “Aviation is a tremendous force for good, keeping the world connected, but we have to do that sustainably. If SAF production can be scaled up – and aviation needs 500 million tonnes a year by 2050 – we can make a huge contribution for our planet.”
Stein added: “We know that is a huge undertaking and will require teamwork right across a number of stakeholders, including aviation, the fuel industry and government bodies. These tests are a contribution to the SAF debate, aiming to demonstrate that our current engines can operate with 100% SAF as a full ‘drop-in’ option, laying the groundwork for moving such fuels towards certification.”
Rolls-Royce’s broader goals also include making two-thirds of Trent engines in service on airliners and three-fifths of the company’s business jet engines able to run 100% SAFs, and replacing 10% of fuel used in civil aerospace testing and development activities with SAFs. Shell Aviation, working with SkyNRG, supplied the SAF for the tests last year and provided AeroShell lubricants for the ALECSys engine test programme. Building on the partnership, Rolls-Royce and Shell signed a memorandum of understanding in July to undertake further test work on SAFs.
Sustainable fuels are not the only new technologies that will be evaluated in Testbed 80. Even the testing facilities themselves are continuously reviewed. Rolls-Royce said: “We’re future-proofing Testbed 80, enabling future technology to be installed to test hybrid or all-electric flight systems. We’re working on different electrification projects, including ACCEL, an all-electric plane set to break records. We’ll need to test electric technologies to the limit – and Testbed 80 will play an important part.”
Such is the scope of the work to be undertaken at Testbed 80 that the biggest mystery may well prove to be how Rolls-Royce fared without it.
30 images per second
Rolls-Royce is the only aero engine manufacturer to X-ray running engines. Darren O’Neill, project engineer test capability, Rolls-Royce, explained: “Our X-ray capabilities allow us to look at minute levels of detail and be extremely targeted. Our engines are made up of more than 20,000 components and, using X-ray technology, we can look at how they behave in extreme detail, under different conditions.”
X-raying running engines is not new at Rolls-Royce. It was first used in the 1970s when a traditional film plate method captured ten images per shift. Current techniques in use at the company’s other testbeds capture one image every six seconds, which sounds like good going, but Testbed 80 provides a substantial leap forward.
O’Neill said: “We’ll capture 30 images every second. The images will be sharper than ever before, and will be instantly available to engineers, who can combine them with other data points to understand what happens to an engine component during specific conditions.”
According to Rolls-Royce, it currently takes around ten days to set up a testbed to perform an X-ray on a running engine. In Testbed 80, this will be reduced to just one day.
O’Neill concluded: “Everything we do at Testbed 80 is about getting better data faster.”
Building a testbed
Rolls-Royce CEO Warren East described Testbed 80 not just as an “incredible piece of infrastructure” but also “a very visible sign” of the company’s commitment to Derby. The facility, he said, “secures the future” of the city as the home of large engine development, “continuing a history that began in the late 1960s with the RB211”.
Norder engineering consultancy, based in Belper, just over ten miles from Derby, was the civil, structural and architectural consultant and principal designer for Testbed 80, with MDS Aero Support Corporation of Ottawa, Canada, also contributing to design and construction.
Adjacent blocks housing offices, conference rooms, a canteen, welfare, workshop and plant facilities consist of steel frame construction with horizontally laid cladding panels to match the existing buildings.
Norder explained: “Due to the nature of test bed operations, key considerations for this project were preventing emissions from noise, vibrations and X-ray as these factors could have a detrimental effect on both the staff in the adjacent office block and workshop, and on the surrounding population.
“By collaborating with the aerospace test facility designers, and engaging an acoustic engineer, [we were] able to produce a design that not only met the requirements but should achieve an output that is two decibels below existing site noise levels.”