We spent the day at the Canadian Aviation and Space Museum, which has an excellent collection. The space part's a bit thin, but then Canada's not exactly a space powerhouse despite what we tell ourselves.
Napier Sabre 24 cylinder sleeve valve engine
I'm always a pilgrim to the engine section. Engines are a highly compressed amalgams of theory made real. Every valve, pump, duct, nut, bolt, piston, housing, even the metal threads on the hoses above, even the things that happen inside the engine, has been defined by numbers and mathematics. Numbers into the real world, and not just into a static object, but an object that actually changes the world by converting one kind of energy into another.
If the great piston engines seem to be carved out of solid metal, the jet turbines are often delicate sheet metal origami of the highest order. Only the discoloration of the fins gives a clue to the roaring, blistering blast of hot gases:
Jet Turbine Exhaust