How do jet engines work?
Welcome! I'm so excited to explore the incredible world of aviation with you. Jet engines are absolute marvels of engineering, and we'll break down exactly how they tame fire and air to fly.
To make sure we tailor this journey perfectly to you, what brings you to learning about jet engines today? Do you already have a bit of a background in physics or engineering, or are you starting completely fresh?
I have some physics/engineering background and want to go deep.
Since you have a background in physics and engineering, we can jump straight past the high-level fluff and look at the real mechanics of how these machines operate.
Your path
Anatomy of the Core Engine
Types of Jet Engines
The Governing Physics Newton and Thrust
At its absolute core, a jet engine is a momentum machine. It works by continuously sucking in a large mass of air at the front, heating it to drastically increase its thermal energy, and then expanding and accelerating that gas out the back at a much higher velocity.
This is a direct application of of Motion. The force required to accelerate the fluid mass rearward generates an equal and opposite reaction force, which we call thrust, pushing the engine forward.
Notice what this formula tells us: to maximize your thrust force, you have two primary engineering levers. You can either accelerate a small amount of air to an extremely high velocity (which is what older, loud do), or you can accelerate a massive volume of air to a more moderate velocity (which is how modern commercial turbofans achieve high efficiency).