UCL Rocket Team Hot-Fires 3D-Printed LOX IPA Engine

A student team pushed a 3D-printed liquid rocket engine through its first hot-fire test

University College London's UCL Rocket team, working with Chinese metal 3D printer maker Eplus3D, successfully tested a regeneratively cooled liquid oxygen and isopropyl alcohol engine. The 7 kilonewton engine uses LOX as both oxidizer and coolant, with IPA serving as fuel. The design keeps the combustion chamber from melting by running extremely cold liquid oxygen through 57 tiny channels machined into the chamber wall before burning it alongside the fuel.

The chamber itself is 3D-printed in CuCrZr copper alloy on an Eplus3D EP-M300 machine. The team also used an EP-MC400 to remove unfused powder from internal channels after printing. This step matters: any leftover powder becomes debris during final machining.

That debris became the test's biggest surprise. After final subtractive machining, 33% of the active coolant channel area was blocked by metallic swarf. The chips were not part of the original test plan. Rather than abort, the team cut throttle in half and added 2% PDMS to the fuel mix. The chamber survived the test without warping.

The team learned that post-machining cleanliness is as important as the original print quality. Processes like Extrude Hone or REM could have cleared the channels, but they were not available for this build. The experience gives UCL Rocket concrete data on cooling sensitivity and combustion behavior as it moves toward more powerful engines.

UCL Rocket previously competed in Race2Space, the UK student rocketry program sponsored by the UK Space Agency. That earlier engine ran on nitrous oxide and produced 5 kilonewtons. The LOX/IPA architecture is more complex and runs hotter, which is why the cooling channel design and post-processing matter so much.

The test validates that a student team can move from advanced design to flight-ready hardware using commercially available metal 3D printers. Eplus3D says the partnership helped turn computer models into test-ready propulsion parts and confirmed the cryogenic engine concept works in practice.