Engines

Turbine engines have revolutionized the way air travel is performed today. Unlike the older reciprocating prop engines that use to carry passengers to their destinations, jet engines provide much less vibrations, less noise, increased aircraft performance, increased reliability, and an easier maintenance program. The evolution of the jet engine has been pretty amazing as can be seen by some of the newer engine options out on the market today. Classification of turbine engines come from the type of compressor they use which fall into three categories; centrifugal flow, axial flow, and centrifugal- axial flow. The type of turbine engine and power it produces is dependent on the path that the air takes through the engine and include; turbojet, turboprop, turbofan, and turboshaft engines. The real world American Airlines/Eagle fleet operates turbofan engines on the entire fleet as the older turboprop aircraft, such as the ATR-72 and Saab 340, have been retired.

Turbofan Engines

Turbofan engines are unique in that their output of thrust on takeoff is lower meaning it does not reach peak performance and efficiency until it is at higher speeds and altitudes. This is why you will see modern aircraft elect to get as high as they can as quickly as possible, and then stay up at altitude as long as possible while opting for as close to an idle descent as possible.

As you can see in the diagram, the engine is made up of an air inlet, compressor section, combustion chamber, turbine section, and then an exhaust. As air enters through the inlet it splits into two directions and either bypasses the engine core (bypass air) or is entered into the core’s compressor section. The amount of air that bypasses the engine core in comparison to that which enters the compressor section is how the engine’s bypass ratio is determined.

To find out more about how jet engines operate, we recommend this quick video from Rolls-Royce found on YouTube (https://www.youtube.com/watch?v=JxkJ-FwFeVI).