Turbojet vs. Turbofan — What's the Difference?

Turbojet engines, utilized primarily in military and high-speed aircraft, work by compressing air and mixing it with fuel for combustion, producing a high-speed exhaust jet that propels the aircraft. In contrast, turbofan engines include an additional fan at the front, which pushes a large volume of air around the outside of the engine, enhancing thrust and fuel efficiency.

The design of a turbojet is relatively simple with fewer moving parts, which generally translates to lower maintenance costs but higher fuel consumption. On the other hand, turbofans are more complex and costly to maintain but significantly reduce fuel costs, making them economically preferable for commercial use.

Turbojets are characterized by their high exhaust speeds, making them efficient at supersonic speeds and suitable for applications like fighter jets and the Concorde. Whereas turbofans are optimized for subsonic speeds, with their bypassed air reducing noise and improving thrust efficiency, ideal for passenger jets.

Noise levels in turbojets are considerably higher due to the high-speed exhaust jet. Turbofan engines, by incorporating a large fan and bypassing a significant portion of air, generate less noise, aligning better with modern noise regulations in aviation.

The operational efficiency of turbojets decreases at slower speeds and lower altitudes; thus, they are less suited for typical commercial flight paths. Conversely, turbofans deliver optimal performance over a wide range of speeds and altitudes, meeting the diverse requirements of commercial aviation.