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PROPULSION SCIENCE · BEGINNER'S GUIDE
PROPULSEUM
The Encyclopedia of Propulsion.
Scroll down and watch a jet engine take itself apart, piece by piece — and put itself back together to explain exactly how it turns air into thrust.
Breathing the Sky
Every jet engine starts by inhaling. A giant fan at the front pulls in huge volumes of air, splitting it between the engine core and a bypass duct wrapped around it. The more air the engine can breathe, the more thrust it can eventually produce.
The Squeeze
Incoming air enters a stack of spinning blades called the compressor. Stage after stage, the blades pack the air into an ever-smaller space, raising its pressure and temperature long before it ever meets a spark.
The Bang
Inside the combustor, compressed air meets a continuous mist of fuel and ignites. It isn't an explosion but a controlled, roaring flame burning past 1,500°C, rapidly expanding the gas toward the back of the engine.
Powering the Cycle
The scorching gas blasts through a second set of blades — the turbine — connected by a shaft to the compressor and fan up front. Spinning the turbine powers the very components that fed it, keeping the whole cycle self-sustaining.
Newton Takes Over
What's left of the high-energy gas accelerates out through the nozzle at tremendous speed. For every action there's an equal and opposite reaction — mass thrown backward pushes the engine, and everything attached to it, forward.
Four words, one cycle
Intake
The fan draws in a continuous stream of air, feeding both the core and the bypass duct.
Compression
Rotating blades compress that air down to a fraction of its original volume.
Combustion
Fuel ignites in the compressed air, releasing the energy stored inside it.
Thrust
Expanding gas exits at speed through the nozzle, driving the engine forward.