Our sustainability journey
The journey to sustainability may seem like something relatively recent but in fact dates back decades, with that destination often going under another name. Jacqui Sutton, Chief Customer Officer, Civil Aerospace, explains.
Sometimes the most remarkable journeys are made up of the shortest steps, and sometimes they can take you to new, unexpected, destinations.
In the world of science and engineering there are the occasional Eureka moments, but progress is normally defined by small, continual, improvements. And when those incremental advances are put together they make a sizeable difference.
The gas turbine is just such an example. Its originator, Sir Frank Whittle, would be able to recognise both the product and the principles of how it delivers propulsion 80 years after his W.1 engine took to the skies for the first time.
But he would marvel at the incredible engineering that has driven the aero engine industry - firstly to make their engines ever more reliable and then, in a post-OPEC world where fuelling flight became a significant cost element, efficiency.
Teams of scientists have finessed each of the 38,000 parts of a gas turbine to create each percentage of efficiency improvements.
We have constantly taken physics to its limits on this search. Over the decades we have refined how to create a high-pressure turbine blade as a single crystal of a specialist alloy in a vacuum furnace. As it grows, it incorporates a complex series of air passages to cool the blade. Then it needs external cooling holes created by incredibly accurate laser drilling. And on top of all that is a thermal barrier coating that enables it to live in the high-pressure turbine, where the gas temperature is at least 400 degrees above the melting point of the blade's alloy. Every time the plane takes-off this single blade develops the same horsepower as a Formula 1 racing car, and yet it can travel 10 million miles before it needs replacing.
That sort of performance, achieved under extremes of heat and pressure, requires a precision of design and manufacture that is measured in microns - to the thickness of a human hair, and it has to be exactly right. Every time.
If we take the fan blade, it may look unchanged over the years, but look closer and look inside and we see continual change. From straight edges to scimitar-shaped blades designed to cut through the air more effectively, from solid steel to titanium blades that are actually hollow with reinforced girders within them - through a process known as superplastic formation and diffusion bonding - each improvement has had to prove itself and its efficiency benefits to make its way onto the final product.
Each improvement has had an enormous amount of engineering support. Each new Trent engine has been the result of years of development involving thousands of scientists and engineers, and a development programme where we have run, tested, examined and, in some cases, destroyed nine full engines over 18 months of frenetic activity.
Each improvement has taken efficiency that bit further forward. The creators of the Rolls-Royce Trent XWB engine that first flew in service in 2015 and is the most efficient large gas turbine flying today, are able to look back and recognise that their creation is 15 per cent more efficient than the very first Trent, the Trent 700, that entered service in 1995. Or, if they wanted to cast their gaze back even further, 80 per cent more efficient than the engines that powered aircraft of the 1960s.
But that search for efficiency was always part of another journey - towards sustainability.
For every fraction of a percent saved in fuel burn is, of course, a fraction of a percent saved in resulting emissions. And while that has always been recognised, it has never been of more consequence than now, as we prepare to reconnect again but have a greater appreciation of just how fragile the world is. And that is why the efficiency journey continues, perhaps with even more urgency than ever before.
We see it right now in the latest engines just taking to the skies. To return to those cooling holes, we are now taking their capabilities to the next level thanks to Additive Layer Manufacturing (ALM), also known as 3D printing.
Our Pearl 10x business jet engine features cooling holes that can, remarkably, turn back on themselves in a loop and then fan out onto their combustor tiles. Why is this important? Because performing that loop means the cooling air picks up the heat from the tiles in the most effective way and the fan-shaped hole exit generate a uniform protective film of air on the hot combustor tile surface. And ALM allows those holes to be created where they couldn't be done before. The outcome? More efficient combustor cooling, a reduction in turbine "hot spots" and lower emissions.
And ALM doesn't stop there, it has the capability to replace traditional manufacturing to create parts that are lighter - and reduced weight further reduces fuel burn emissions.
This patient journey is neverending and even as Pearl 10X prepares to enter service, a variety of programmes are underway to take efficiency and sustainability to the next level.
A demonstrator for the next generation of Rolls-Royce gas turbine is being built right now in Derby. UltraFan®, a scaleable technology capable of powering both narrowbody and widebody future aircraft programmes continues to use technology to drive even more improvements.
They include further improvements to the engine core architecture including lean burn technology, new carbon/titanium fan blades and composite casing, advanced ceramic matrix composites, and a new geared design powered by the world's most powerful gearbox in aerospace.
It is anticipated that UltraFan will be available for service around the turn of the decade, and when its creators look back, they will recognise they have taken fuel efficiency a whole 25% further than the Trent 700.
The development of UltraFan, and the broader sustainability journey, cannot be undertaken without broader support. That includes a myriad of industrial partnerships and also, importantly, governmental support too.
That's why we were recently delighted to host UK Business Secretary Kwasi Kwarteng as he opened our newly-built Testbed 80 facility - where UltraFan will run for the first time. As Mr Kwarteng said: "This testbed here in Derby shows that the UK remains a global leader in aeroengine technology. I'm proud that we're supporting Rolls-Royce's development of the highly-efficient UltraFan engine, as well as investment in green and cutting-edge aerospace technology here in the UK that will create high-skilled, well-paid jobs for decades to come.
"As the civil aviation market recovers, the innovation of great British companies such as Rolls-Royce and the entire aerospace sector are central to our plans to build back better from the pandemic and end our contribution to climate change by 2050."
But new opportunities are also emerging that can completely transform gas turbine sustainability, not through further improvements to its inner working, but from the fuel itself.
Sustainable Aviation Fuel offers a transformative future for aviation, creating a cycle of creation and use that has the potential to reduce net CO2 lifecycle emissions by more than 75% compared with traditional jet fuel, or even zero emissions if created by nuclear power plant.
The challenges are making it to scale, making it economically viable, and proving it is technically feasible to use. We are supporting efforts to bring the aviation sector, fuel industry, governments and industry bodies together to break through the barriers that apply to the first issue.
In terms of economics UltraFan's efficiency will help improve the economics of an industry transition to more sustainable fuels, which are likely to be more expensive in the short-term than traditional jet fuel. And we are committed to demonstrating there are no barriers to SAF's use in an engine.
We've already run current Trent and Pearl engines on ground tests using 100% SAF, and found no issues regarding engine performance. And we've supported the ECLIF3 (Emission and Climate Impact of Alternative Fuels) programme that has now flown an Airbus A350 aircraft, powered by a Trent XWB engine.
We will also prove SAF is ready to power our engines of the future - the very first run of UltraFan in 2022 will be on 100% SAF, providing continued reassurance to everyone involved with aviation of its suitability.
Beyond UltraFan there is no shortage of opportunities to improve the gas turbine even further - through electrification, hydrogen, and new materials to just name a few. It will be a continued journey of relentless research, continual testing, and further progress towards an ever-more sustainable world.