Juan David's Newsletter - July 17, 2022
The Jet Engine: The Most Beautiful Engineering Masterpiece
My progress in learning everything about flying has been going strong. In less than a month, my document has grown to be almost 100 pages, and I’ve barely scratched the surface. So much to learn, so much to be curious about. When you’re curious, you’re never bored and you are always happy.
As great as learning is, it doesn’t translate to solving problems or knowing how to build things. My drone project has been a little slow as I got stuck and didn’t know how to move forward but I’m picking it up and continuing to build.
This week, we talked about the most mind-blowing thing I’ve learned in recent months: THE JET ENGINE!!!!!!!!!!!!!!!!!!!! Get excited.
The Jet Engine: The Most Beautiful Engineering Masterpiece
This essay draft is part of an upcoming mega essay (or book) of an exploration of teaching myself EVERYTHING on Flying from Hidden History to Hardcore Engineering.
Jet engines are also known as gas turbines. They work on the principle of taking air in with a fan, compressing it to raise the air pressure, and using it to generate thrust to push the airplane forward.
I was blown away and still am. How the heck do you develop a system that takes air, does something to it, and creates an insane amount of power to amount WHOLE AIRPLANES? Wow.
Jet Engine Parts
I want to go deeper and talk about every part of the engine.
Fan: This is the first component and what sucks the air in. After the air is in, it speeds up and splits up. One part goes through the center of the engine to be used by other engine parts. The second part does not go through the core engine but rather it goes above and below the center of the engine where it produces force to move the airplane forward. A cool fact is that the air from the second part is cooler so it helps quiet the engine as it mixes with the hot air.
Compressor: a compressor compresses air, which sounds simple but it’s essential because the squeeze of air increases the air pressure resulting in greater energy potential. How does this happen? The compressor is made up of fans with blades attached to a shaft.
This compressed air is now ready to go into the combustion chamber.
Combustion Chamber: this is where the fire part starts, quite literally. After the air comes from the fan and goes through the compressor, the air enters this chamber where the air is mixed with fuel and ignited. This mixture of air and fuel catches fire, which raises the temperature and when the temperature goes up, gases expand and are ready to go into the famous TURBINE!
Turbine: the air is coming in HOT!!!!! This high-energy airflow causes the turbine blades to rotate. The turbines are connected by a shaft to turn the blades in the compressor and to spin the fan at the front.
Take a look at the shaft:
The turbine is the most grateful part of the engine as gives energy back to those who came before him, the fan and the compressor. Without the generosity of the turbine, the jet engine would not work.
Now to the last part(s) of the engine.
Nozzle: This is the very end of the engine and where everything leaves, it’s the exit. More technically this is known as the exhaust duct of the engine. It’s the end and last part of the engine but not the least important. Actually, the nozzle produces the thrust for the plane. How? The air that goes through the turbine plus the colder air that did not go through the center of the engine come together to produce a force when exiting the nozzle that acts to propel the engine, and of course the airplane.
Sometimes before the nozzle, you may add a mixer that combines the high temperature from the sides and low-temperature temperatures coming from the center of the engine to help make the engine quieter. The mixer blends them together and ensures thorough mixing before they are ejected into the atmosphere.
The loudest parts of the engine? The compressor, the turbine, and the exhaust.
The faster the airflow, the louder it gets.
But the exhaust is far the greatest, which makes the other sounds insignificant. The speed difference between the exhaust jet and the atmosphere causes a shearing action, which creates a violent and turbulent mixing pattern. 160 decibels is the exhaust while the compressor or the turbine is 70 or 60 decibels respectively.
However in a bypass engine, the exhaust nose drops because of the reduction in the velocity of that exhaust but because of the greater power, the turbine and compressor generate higher noise.
In a high ratio bypass engine, the noise from the exhaust is lower than the noise from the compressor (fan) is greater!
Once engine manufacturers figured out a way to reduce noise levels from what used to be the loudest engine part, the exhaust. They now concentrate on lowering noise levels from the rest of the engine like the fan and the turbine. Both which can be reduced by using noise-absorbing materials which are really efficient. The tradeoff is the added weight and higher friction which causes a slight increase in fuel consumption.
And that right there, my friends, is how jet engines work. One of the many beautiful engineering masterpieces that makes a plane take off. After the Wright brothers paved the way, now we were ready to make planes better and faster, and the jet engine was a key part of this invention.
But progress isn’t guaranteed and we must work to make it happen. After the jet engine was invented, only incremental progress was made until we peaked with supersonic flight with the Concorde and fighter planes. In fact, we went backward after the Concorde stopped flying. Sure The Concorde wasn’t economically viable, the accidents, and a few other reasons but that just can’t be the whole story. In fact, we are flying planes at the same speed as we were in the 1960s. 60 years?!!!! And no progress?!
One of you will object and will tell me, “But Juan David… I can go to my computer and use Zoom, and it’s faster than anything we will ever create in the near term future.”
But don’t you ever forget, with enough inspiration and determination, humans are capable of accomplishing the unthinkable.
Planes are massively underrated. We take them for granted. Few of us know why they work or how they work or even the beautiful and brave history of flight.
Another massively underrated thing is water objects like boats and submarines. Crazier yet, we have very little idea of what is going on with the ocean. It’s too dark and hard to explore. What kind of animals and life exists out there? Exploring the ocean is as hard as exploring space. In the future, I’d like to create three types of companies to explore the ocean, the air, and space.
Anyways here’s a picture of a submarine! I’ll see you next week. As always, let me know what you think of these “flying” essays.
Up in the sky,
Juan David Campolargo
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