Variable stator vane · 7 cm

One of the two small stator vanes, 7 centimetres. Everything the big ones have is here — eye, spigot, twisted aerofoil — just at a smaller scale.

Inside a jet engine's compressor, rotating and stationary blade rows alternate. The stationary ones — the stator vanes — straighten the air for the next stage. Some of them are adjustable: they sit in bearings and are turned together by a ring, so the compressor works as cleanly at idle as it does at full power. That is why this piece has an eye with a bore at its head, where the lever engages, and a spigot on the reverse that runs in the casing.

Which engine this came from is not known. There are no papers with it, and apart from its shape nothing identifies the type. The material cannot be named without testing either: compressor blades use titanium, steel or a nickel alloy depending on the stage. What is certain is in the key facts — the rest stays open.

• Length 7 cm
• Flat bearing eye with bore at the head
• Guide spigot on the reverse
• Twisted aerofoil, sharp edges
• Metal, alloy undetermined
• Loose single piece, no stand

Used, unremarkable. Bright front, darker reverse, fine scratches across the surface. Edges and bore in order.