Propulsion
Commercial jetliners - like all airplanes - fly according to basic physical principles. To find out how they work, following the links below:
- Airplane Parts
- Aerodynamics
- Propulsion
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A jet engine uses a fan on the front to suck in air, mixes it with burning fuel, and blasts the expanded air-gas mixture out the back. In the process, it turns a turbine in the back of the engine that spins the fan in the front. Because every action has an equal and opposite reaction, a jetliner surges forward as its engines push air backward.
Fanjets
High-bypass-ratio fanjets are the most reliable engines ever developed. Fundamentally simple, fanjets are fuel efficient and quiet turbine engines. They feature continuous combustion and smooth rotation, unlike the internal-combustion engine of a car, truck or bus. A fanjet engine has three sections:
- Fan unit and compressor section
- Combustion chamber
- Turbine section
The compressors pressurize air and feed it aft. Most goes around the engine core through a nozzle-shaped chamber. The rest goes through the engine core where it mixes with fuel and ignites. The hot expanding combustion efflux passes through the turbine section, spinning the turbine as it exits the engine.
The spinning turbine turns the engine shaft. The rotating shaft spins the fan on the front of the engine. The fan compresses more air and keeps this continuous cycle going.