Jet engine: what it is, how it works and types

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Although on this website we focus on land vehicles, such as cars and motorcycles, surely motor lovers will also be curious to know more about this aviation jet engine, although they have also been used in land vehicles to break speed records: in crazy prototypes.

The jet engine, also known as a turbojet, is a type of internal combustion engine that uses compressed air and fuel to generate thrust and propel the vehicle. It is a revolutionary invention that has transformed air transportation, allowing flights at speeds and altitudes previously unimaginable. In these cases, the fuel used is not diesel or gasoline, but kerosene is used due to its properties.

Kerosene, or paraffin, is a liquid fuel derived from petroleum that is primarily used to fuel jet engines. Other conventional fuels are not used, since kerosene has advantages such as its high ignition point, its thermal stability, low sulfur content, and high calorific value, which allows high yields.

jet engine parts

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Un jet engine consists of some fundamental parts What you should know before continuing to see more about these engines:

  • Air entrance: Air is drawn in through the front of the engine through an air inlet.
  • Compressor: This sucked air is compressed by a compressor, which consists of a series of propellers with blades specially designed to increase its pressure and temperature as it travels towards the rear part of the engine.
  • Combustion chamber: Compressed air reaches the combustion chamber, which is mixed with pulverized fuel. This mixture is ignited by a spark, generating a large amount of hot gases at high pressure.
  • Turbine: The hot combustion gases expand their volume through a series of nozzles directed towards the turbine blades. The force of the expanding gas rotates the turbine, providing energy for the operation of the engine.
  • exhaust nozzle: The exhaust gases from the turbine are expelled at high speed through an exhaust nozzle. This expulsion of gases generates thrust that propels the aircraft forward.
As you know, thanks to this thrust, the wing will do its aerodynamic magic to make the device fly, when its shape causes the air flow over the top to accelerate (reducing downward pressure) and reducing the speed of the air flow. on the underside of the wing, which increases the pressure. When the pressure at the bottom of the wing exceeds the pressure above, the plane takes off...

Thanks to their design, these jet engines provide some advantages, including having a huge thrust equivalent to thousands of horsesIn addition, given their operation in terms of air intake, they work without problem at high altitudes without being affected like atmospheric or turbo ones (to a lesser extent). They also tend to have enormous reliability and durability. However, they also have some disadvantages, such as their great complexity, their high cost, the enormous noise they generate, and the high fuel consumption, as well as the enormous polluting emissions.

Horsepower (HP) is not the standard measure for quantifying the power of a jet engine. Instead, units such as thrust (measured in Newtons or pounds of force) or shaft power (measured in kilowatts or horsepower) are used. When we talk about small jet engines for light aircraft or small jets, up to 5000 HP can be generated, for military combat aircraft, such as fighters, even forces equivalent to 100.000 HP can be achieved. Commercial passenger or cargo aircraft can range from 10.000 to 50.000 HP.

Types of jet engine

As for types of jet engine, we have:

  • Turbojet: the most common type of jet engine, used in passenger and military aircraft. In this engine, compressed air is mixed with fuel and burned in the combustion chamber. The hot gases expand their volume and are expelled at high speed through an exhaust nozzle, generating thrust. It offers great power, simplicity and reliability. But its consumption is higher, given its lower efficiency. Some examples of these engines are the Pratt & Whitney JT8D used in the Boeing 737 or the General Electric F414 of the F-18 Hornet fighter jet.
  • Turbofan: is a variant of the turbojet that uses a fan to generate additional airflow around the engine. Some of the compressed air is directed to the fan, generating a low-speed air flow that passes around the motor. Hot combustion gases mix with this airflow, increasing thrust and efficiency. It has greater efficiency than the previous one, and greater performance, but it is also more complex and expensive. Examples are the CFM International CFM56 for the Airbus A320, or the Rolls-Royce Trent 900 for the Boeing 787.
  • turbopropeller- Combines a jet engine with a propeller to generate thrust. In this case, part of the compressed air is directed to the turbine, which drives the propeller. Hot combustion gases are expelled through an exhaust nozzle, generating additional thrust. It has good efficiency, and is ideal for short takeoff and landing (STOL) aircraft. However, they offer lower performance. Some cases are the Rolls-Royce AE2100 or the Pratt & Whitney PT6A of the ATR 42 and Bombardier Q400 respectively.
  • Turboramjet: a type of hybrid jet engine that combines a jet engine with a ramjet engine. At low speeds, the engine operates like a conventional turbojet. As speed increases, the air compressed by the compressor is heated primarily by friction with the inlet air, igniting the fuel without the need for a combustion chamber. It offers greater efficiency at high speeds, and less at low speeds. Furthermore, it is complex. Examples are the Pratt & Whitney J58 of the SR-71 Blackbird, or the General Electric J93 of the Lockheed A-12, both combat fighters.
  • scramjet: Lastly, this is a type of hypersonic jet engine that uses supersonic combustion to generate thrust. The air compressed by the compressor is heated to extremely high temperatures by friction with the inlet air, igniting the fuel without the need for a combustion chamber or rotating parts. It allows for high speeds and simplicity, but is complex and still under development. Examples are the Boeing Flight Vehicle 2 and the X-51 Waverider, both experimental hypersonic aircraft.

What are the sky trails left by these engines? Chemtrails

chemtrails

Hen/Stag Contrails, or contrails, are white clouds that form behind airplanes at high altitudes.. They are made up of microwater droplets or ice crystals that form when water vapor emitted by jet engines condenses in the cold, dry air of the upper atmosphere. Their formation depends on the ambient temperature, relative humidity, altitude (between 6000 and 12000 meters) and type of engine, which is why some airplanes do not leave this type of trails.

If you are a friend of conspiracies, there is also the theory of the "chemtrails", which alleges that they are chemtrails left intentionally for different purposes, such as changing the weather, among others...


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