Is an airliner a jet

Generally speaking, an aircraft like the 737 can be regarded as a jet.

However, from the perspective of aeronautics, the optional CFM 56 engine or IAE V2500 engine of the 737 is a turbofan engine.

It can't be considered a jet engine. The only real jet engine is a turbojet engine.

There is an essential difference between the two, the turbofan engine.

The thrust mainly comes from the fan, and most of the high-temperature gas generated after combustion in the combustion chamber is used to push the turbine, and the turbine drives the fan to rotate to generate thrust. Most of the gas energy coming out of the tail spray is consumed on the turbine, which provides only about 20 to 30 thrust. The thrust of the turbojet engine mainly comes from the tail jet, and it does not have a first-stage fan, that is, the circle of blades that can be seen from the front of the 737 engine, so the engine inlet of the fighter equipped with the turbojet engine is basically not circular, but with the aerodynamic shape of the fuselage, it is made into the most suitable air inlet shape for high-speed flight.

The main thrust of the turbojet engine comes from the tail jet, which is the work of real combustion chamber combustion.

Gas expansion, high-speed ejection, with the recoil force of gas to propel the aircraft forward, as for the fighter jet can spew flames behind, is to add a ramjet engine behind the tail spray of the turbojet engine, or called afterburner, the gas out of the main engine is burned again to accelerate, mainly used for Mach 2.

Above supersonic flight. Because the gas from the combustion chamber of the main engine has to impact the turbine, and then the turbo drives the compressor, so after the tail is sprayed, the temperature has been reduced a lot, basically kept at about 600 degrees, and the flame is usually not visible, and once the afterburner works, its gas is sprayed out without doing any extra work, directly from the tail, the temperature can be as high as 1200 degrees, so it seems that the fire is sprayed instead of the exhaust.

As for the part that can be seen in the engine of the 737, the thread-like thing is the white paint painted on the fan rectifier cone, hehe, the function of the fan rectifier cone is to rectify the airflow, so that the air flow enters the fan and compressor in a regular direction, and the thread-like thing that can be seen is used to prevent bird strikes. The industry calls the rectifier cone Eagle Eye.

The reason is that it is painted with a white paint tape that rotates clockwise, and when the engine rotates, it looks like an eagle's eye from the front, and most birds have to run when they see an eagle, so this thing is used to scare birds. As for the propellers.

Wrapped in a large cylinder, this statement is basically correct, the engine body does not include the big cylinder, that is just four pieces of wrapping around the engine, two pieces of fan skin, two pieces of thrust reverser skin, they are installed on the hanger of the aircraft body, not with the engine together, look at this picture, this is the optional CFM56-5B engine on the 737. In fact, its principle is similar to that of the propeller engine, the difference is that the propeller of the propeller engine is called the pulling force, and the fan of the turbofan engine is called thrust.