GREEN FOR GO ROLLS-ROYCE TARGETS ENVIRONMENTAL AMBITIONS

Rolls-Royce-opened its new Testbed 80 facility, the largest indoor test facility in the world, at its headquarters in Derby, UK in May. But Rolls-Royce is eyeing more than traditional powerplant testing for this new facility as the company goes all in on sustainability and emissions reduction.

In May, Rolls-Royce-opened its new Testbed 80 facility at its headquarters in Derby, UK, but this is not just a new engine test cell, it is an important marker for the company’s ambitions for the future as it aims to become a major player in environmentally friendly aviation.

Simon Burr, director of Product Development and Technology, explains that Testbed 80 joins a network of engine, system and component test facilities in the UK, Europe and North America (plus a Boeing 747-200 and a 747-400 used for flight trials) and its work will include the development of the UltraFan ultra-high bypass ratio technology demonstrator. The target is a 25% improvement in efficiency over the Trent 700.

Left, a drone’s eye view of the new Rolls-Royce Testbed 80 faciltiy in Derby, UK. Above, a rendering of the testbed.

However, the £90 million investment will also be used to improve the fuel efficiency and durability of existing engines and to develop more environmentally friendly alternative electric and hybrid powerplant systems for the future. This reflects the company’s involvement in a number of projects internationally that are pushing for cleaner aviation.

The size of the building makes it the largest indoor test facility in the world. This has been dictated by the hugely increased airflow mass requirements of UltraFan. The demonstrator will have a thrust rating of 85,000lb, although the technology has been designed to be scalable from 25,000lb to 100,000lb, making any future production engines capable of powering both narrowbody and widebody aircraft. At its higher thrust, the engine has a 15:1 bypass ratio and the geared fan has a diameter of 140in. That compares to 9.3:1 and 118in respectively for the Trent XWB-84 for the Airbus A350.

To accommodate that fan size, there is a 49ft diameter main test bed cross section, while to produce the correct diffusion of the bypass air and exhaust gases, there is a long augmentor tube some 110ft long. The mixture is then turned through 90° before being vented through a 123ft high exhaust stack. The overall length of the building is 425.5ft.

Capabilities will include endurance testing, blade-off tests and water, sand and bird ingestion, while a dynamic X-ray capability will monitor clearances between moving parts, capturing 30 images/second. The latter is being funded by the UK Aerospace Technology Institute (ATI) under its Proving Advanced Concept Engines (PACE) program. It will be mounted on the pylon, which is being supplied by UK-based Hyde Group.

Design and construction of the test cell was led by MDS Aero Support Corporation of Ottawa, Canada. They also supplied all of the test systems. Rolls-Royce image.

Most test cells have an overhead gantry system that allows engines to be raised and moved from the preparation area and mated directly to the pylon. In Testbed 80, engines will be transferred on a robotic mover, which will then raise the entire propulsion unit to the pylon. Although this makes the vehicle much bigger and stronger, it requires less maintenance and improves safety.

Of course, as well as the usual connection via the pylon, the engines will be heavily instrumented, with more than 10,000 parameters being measured (3,500 to 5,000 on current engines), with up to 200,000 samples per second, giving a data flow of 1 terabyte/hour.

The test cell was used for the first time 12 January 2021, with a Trent engine, which reached 100,000lb thrust just a week later — the test cell maximum is 155,000lb of thrust. These were functionality checks. As no production engines will be tested, it does not have to be calibrated and approved by the aviation authorities.

Design and construction have been led by MDS Aero Support Corporation of Ottawa, Canada, a long-term partner of the engine OEM, which also supplied all of the test systems, including aerodynamic and acoustic elements, a thrust measurement system, engine adapters for current and future engines, and mechanical and fluid support systems. It also supplied its nxDAS data acquisition and controls system. Building work started in May 2018.

Noise has been an important consideration throughout the design process. As well as external noise (the exhaust is quiet enough that the facility can be used at any time of day or night), great care has been taken to avoid infrasound, low frequency noise that can have a detrimental effect on the integrity of the building as well as the employees working in close proximity. MDS used Computational Fluid Dynamics to ensure there were no tones or resonances in the air flow. This has involved the use of double skinned walls in some areas, while ballistic protection has been installed for blade off tests. In fact, noise from the test cell is so low that it is relayed into the control room, as skilled engineers can identify a problem by ear, with the possibility it may not show up on the telemetry.

The first UltraFan run in Testbed 80 is scheduled for next year but it is already being used for endurance tests and the evaluation of new manufacturing processes coatings. When that run happens, the engine will be use 100% Sustainable Aviation Fuels (SAF), another part of the environmental program. The facility’s 32,000 USG fuel system was designed to handle different fuel types, including SAF. Burr notes that UltraFan has fuel seals made from synthetic material, which will not suffer degradation like nitrile seals when exposed to SAF over a period of time, one of the reasons for the current limit of a 50/50 maximum blend.

To further this work, at the end of June, Rolls-Royce signed a memorandum of understanding (MoU) with fuel company Shell to progress the use of SAF. This includes Rolls-Royce’s new SAFinity service, providing SAF for business aircraft operators, with Shell as exclusive supplier, but will also involve Rolls-Royce lending its technical expertise to advise Shell in its new fuels development. The two partners will also engage with industry bodies and forums to progress strategic policy issues. One of these is gaining approval for 100% SAF, as the company has a commitment to have all in-production civil aero engines compatible by 2023. In addition, they will assess broader opportunities in other mobility sectors such as shipping and rail.

Rolls-Royce and Norwegian airline Widerøe have been collaborating since 2019 to develop electric aircraft with a tremendous reduction in emissions. The two are hoping for a 2030 entry to commercial service. Rolls-Royce image.

Speaking at the announcement of the MoU, Paul Stein, chief technology officer at Rolls-Royce, said: “We believe that working together on these aims can deliver benefits for both the development of new innovations as well as collaborating to find ways to unlock the net carbon emissions reduction potential of technology that is already in use today. SAFs will not only power large aircraft and business aviation, but also hybrid electric Urban Air Mobility and the forthcoming generation of hybrid fixed wing city hoppers, which is why we place such importance on the ramp up of SAF adoption across the industry.”

Electric/hybrid aircraft

The company is heavily involved in electric and hybrid propulsion and is making real progress, along with making significant investments. Electric aircraft are often seen as too limited for commercial operations but one project shows that reality is not far away.

Rolls-Royce and Norwegian airline Widerøe announced a joint research program in 2019 to evaluate and develop electrical aircraft concepts that would enter commercial service by 2030 and produce an 80% emission reduction in domestic flights by 2040.

The reason for the collaboration is that Widerøe currently flies Bombardier Dash 8 aircraft on a Short Take-off and Landing (STOL) network, with many Public Service Obligation routes, linking remote communities with larger towns and cities. Before the pandemic, there were around 400 flights per day using a network of 44 airports, and 74% of the flights had distances less than 170 miles, with the shortest flight durations between seven and 15 minutes. Those operating parameters are ideal for electric aircraft

Separately, Rolls-Royce had been working with Italian aircraft manufacturer Tecnam on an electric version of its 11-seat Tecnam P2012 Traveller, called P-Volt, announced in October 2020. This, in turn, built on the H3PS project: a hybrid electric version of the P2010 four-seater, pairing an electric motor from Rolls-Royce with a combustion engine from Rotax.

In March this year, the three companies joined forces, accelerating the program to entry into service of an electric P2012 in 2026.

Shown here is the hybrid engine PGS1, which Rolls-Royce says forms an important element of their sustainability strategy. Rolls-Royce image.

On a larger scale, July saw a further step forward in the 2.5-megawatt (MW) Power Generation System 1 (PGS1) demonstrator program for future regional aircraft. This had its roots in the Airbus/Rolls-Royce/Siemens E-Fan X project, which would have seen one of four Lycoming ALF502 engines on a BAe RJ100 test aircraft replaced with a hybrid engine combining an AE2100 turboprop with a 2.5MW generator. Sadly, COVID-19 caused Airbus to pull the plug in April 2020, by which time Rolls-Royce had purchased the electric propulsion branch of Siemens, transferring the work to Rolls-Royce Electrical Norway. As yet another pointer to the company’s environmental commitment, it took over development of the hybrid engine itself, turning it into PGS1.

The July event saw the delivery of the generator and related power electronics delivered from Trondheim, Norway, to the newly-renovated Testbed 108 in Bristol, UK, where the AE2100 engine element, specialist controls and the thermal management system from Indianapolis had already been run.

Again, looking at other industry sectors, in addition to hybrid-electric propulsion, the generator could also be used as part of a ‘more-electric’ system for larger aircraft or within future ground or marine applications. Incidentally, Testbed 80 also has extensive load bank capability to support this type of testing.

Both Testbed 108 and PGS1 have been supported by the UK Aerospace Technology Institute’s MegaFlight project, while design, make and testing of the 2.5MW electrical generator, motor and power electronics in Trondheim has been supported by the EU Clean Sky 2 program.

Finally, Rolls-Royce announced in June that it is planning an £80 million investment in developing energy storage systems (ESS) for electric and hybrid-electric propulsion systems that will enable aircraft to undertake zero emissions flights of over 100 miles on a single charge. That includes eVTOLs (electric vertical take off and landing) in the Urban Air Mobility (UAM) market (where it is working with UK-based Vertical Aerospace on the VA-X4 — see related story page 59) and fixed-wing aircraft, with up to 19 seats in the commuter market. Targets include the creation of around 300 jobs by 2030 and the integration of more than 5 million battery cells per annum into modular systems by 2035.

Rolls-Royce has considerable experience, having designed 10 different aerospace battery systems. Of these, four designs have already flown in three aircraft, accumulating more than 250 hours of flight experience and another two designs will complete their first flight in aircraft in 2021. This includes a battery developed with Electroflight, its UK manufacturing partner in the ACCEL program, which has built the ‘Spirit of Innovation’ (a heavily modified Nemesis NXT racing aircraft). That aircraft is planned to break the world speed record for all-electric aircraft later this year. Another partner in developing energy storage technology is WMG, an academic department at the University of Warwick specializing in collaboration between academia and the public and private sectors, which has extensive knowledge gained through supporting the automotive and other sectors. ATI has once again supported both ACCEL and the initial ESS research and technology.

In Testbed 80, engines will be transferred on a robotic mover, which will then raise the entire propulsion unit to the pylon, Rolls-Royce says. Top image shows the Spirit of Innovation — a battery-driven, heavily modified Nemesis NXT racing aircraft developed with partner Electroflight. Rolls-Royce images.

For a company best known for conventional turbofan and turboprop engines, it is clear that a new Rolls-Royce is emerging, one that is determined to push the boundaries of technology when it comes to greener aviation. This is all the more impressive in the light of the hammering the company has taken because of the pandemic, not just with new production engines but with the TotalCare support business, as flying hours have been slashed.