How jet engines are made

The turbine blades in a jet engine run in gas hotter than the metal they are made of would normally survive.

stations: 7
things upstream: 49
raw sources: 23
steps from the ground: 7

The short version

A jet engine sucks in air, squeezes it with a bank of spinning compressor blades, burns fuel in it and passes the hot gas through a turbine that drives the compressor. Its parts are forged titanium and cast nickel superalloy, machined to tight limits, balanced, assembled in modules and run on a test stand.

Forge the fan and compressor blades

Titanium is pressed hot into blade shapes that must withstand centrifugal pull and the impact of air at speed. The blades are then machined and polished.

Goes in
Titanium
Forge the heavy disks

The disks that hold the blades are forged from nickel-based alloys and titanium, then heat-treated and machined. They spin faster and hotter than almost anything else in a machine.

Goes in
Nickel Titanium
Fit the cast turbine blades

Turbine blades come from a specialist foundry, where they are cast from superalloy around ceramic cores and coated against heat. They sit directly behind the combustor.

Goes in
Turbine blade
Weld the combustor and casings

Sheets of nickel alloy are formed and welded into the burner liner and outer casings, with a ring of fine holes that let cool air in.

Goes in
Nickel
Balance the rotor

The shaft and disks are stacked up and spun on a balancing machine. Material is ground off wherever a heavy spot shows up.
Build it up in modules

Fan, compressor, combustor and turbine are each put together as a module. Modules are then joined, and the fuel, oil and control systems are piped on.
Run it on a test stand

The engine is run through its full power range, and thrust, temperatures and vibration are logged before it is cleared for an airplane.

Goes in
Jet fuel

End of the lineJet engine Next it goes into airliner.

Worth repeating

The GE90 turbofan of the 1990s produced 115,000 pounds of thrust, against 5,000 for a 1950s turbojet.
In-flight shutdowns fell from 40 per 100,000 engine flight hours to under 1 per 100,000 by the late 1990s.
A Heinkel He 178 with a gasoline-fuelled HeS 3 engine flew on August 27, 1939.