A team of engineering and science students from the University of Sheffield has successfully tested a 3D-printed liquid rocket engine, the most powerful student-built engine of its type. Their SunFire engine is the first metallic 3D-printed liquid rocket engine to be built and successfully tested by students in the UK.
The engine, which is similar to the kind used by pioneering space companies such as SpaceX, uses both fuel and an oxidiser rather than breathing in oxygen like a jet engine. It’s also the first UK-student-built engine that is regen-cooled, using fuel to cool the combustion chamber before it’s burnt, which increases the engine’s efficiency and saves weight.
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The students successfully hot fired the engine as part of a week-long competition called Race to Space, in which teams of students from universities across the UK tested rocket engines they have built over the last two academic years. The competition week is believed to have set an unofficial world record itself for the number of different hybrid/liquid rocket engines hot-fired for the first time on one site in one week.
There are only a handful of liquid rocket engines made by students throughout Europe and even fewer regen engines worldwide, and until now, none in the UK made by 3D printing or as powerful as the engine built at Sheffield.
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The Sheffield students built the engine over the last two years outside of their studies as part of the University of Sheffield’s Space Initiative, a programme designed to help STEM students use their skills to tackle some of the space industry’s biggest challenges and help them develop careers in the industry after graduation.
Students in the team, known as Sunride, hope to eventually use the engine to power one of their own rockets to the edge of space and become the first UK student-led team to launch beyond the Kármán line – the arbitrary boundary 100 kilometres above sea level that’s said to be where the atmosphere ends and space begins. The team already holds the UK altitude record for an amateur rocket, which they achieved in 2019.
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The University of Sheffield’s Royce Discovery Centre – a research centre that’s developing the next generation of materials to meet the needs of UK manufacturing – was instrumental in trialling the laser-powder-bed metallic 3D printing that was used to build the engine. The University’s Advanced Manufacturing Research Centre and Faculty of Engineering machined the engine post printing.
‘The hot fire test of our engine was a day I’ll never forget. From coming up with the idea in a coffee shop with two friends more than two years ago, it was amazing when we finally got to fire our rocket engine!’ said Henry Saunders – who led the team last year and is now doing a PhD at the University of Sheffield’s Royce Discovery Centre. ‘Being involved with the SunFire programme provided me with an opportunity to take the engineering science I had learned about in lectures and translate these learnings into a real-world practical application.
‘This, for me, was where the real excitement and learning reinforcements came from, not just seeing a rocket engine on a PowerPoint slide with some equations next to it, but actually being involved in building a rocket engine from scratch,’ he contined. ‘The equations only get you so far. The real learning, for me, came from trying things, failing and then eventually succeeding.’
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‘Additive manufacturing (3D printing) is increasingly being used by rocket companies such as SpaceX as it allows you to build complex, lightweight custom geometries that would not be possible using traditional methods,’ said Alistair John, deputy director of aerospace engineering at the University of Sheffield, who supervised the team. ‘For example, the cooling channels in our engine, which stop the engine melting, despite the 2,000°C combustion temperature, can only be made using 3D printing. Extra-curricular activities such as Sunride and the Race to Space initiative are hugely important as they allow students to apply the knowledge from their degree and push the boundaries of what they can achieve. It is hugely important for the UK space sector that we give our students hands-on, practical experience to develop the skills industry needs.’