Titanium instead of nickel in a printed rocket engine: a claimed 44% saving
Published
What TCT Magazine reports: Skyrora ran six hot-fire tests of its 3.5 kN low-Earth-orbit engine at its Midlothian site. The article describes a titanium-coated component and says Skyrora is said to have cut weight by about 44% by using titanium instead of a nickel-based alloy; it does not say who made the claim or what the weight refers to. It says the component was engineered with Skyrora's in-house Skyprint 2 hybrid directed-energy-deposition printer, under the EU-funded MADE-3D programme. No damage to the modified components was reported. Why it matters for materials: swapping a nickel-based alloy for titanium usually trades high-temperature strength for much lower mass, so it tends to suit a part that sees moderate heat or is protected. That is our inference; the article says only that the part is designed for the engine's demanding thermal environment. Our take: the saving is close to what the density gap alone would give. In our archive Ti-6Al-4V is 4.43 g/cm3 and Inconel 718 is 0.297 lb/in3, about 8.22 g/cm3, so titanium is roughly 46% lighter for the same volume, for those two grades. Which grades Skyrora used is not stated, and the page calls the part titanium-coated and also speaks of using titanium instead of a nickel-based alloy, so we cannot tell a surface layer from a bulk swap. The 44% has no baseline mass, and test durations, measured thrust, pressures and temperatures are not given. Six hot-fires with no reported damage do not show it is flight-qualified. What we would watch: which part it is, how hot it runs, and whether it survives repeated firing. Would you trust titanium there?