The Ridiculous Engineering of Jet Engines

This is one of the most powerful jet engines in the world. And it actually runs at temperatures 250° C hotter than the melting point of the materials that make it up. >> That's 12,200°. >> So the question is, why doesn't a jet engine just melt into a puddle?

We are right at the boundaries of the laws of physics. >> That is wild. It's at the same temperature now as it would be inside the jet engine. But here, they're liquid.

Every time I get on a plane, I'm thinking, "This is never going to work." >> And yet, it does work. Right now, there are over 10,000 planes in the sky powered by engines just like these. Maybe you are on one right now. So, how do they work?

This is a jet engine, specifically a turboan engine. At the front is this giant fan. During takeoff, these rotating blades push 1.3 tons of air backwards every second, and around 10% of that air gets compressed. The compressors force the air into increasingly narrow chambers.

They compress the air to about 50 times atmospheric pressure. And just by doing that, the air heats up to around 600° C. This compressed air is then forced into the combustion chamber where fuel is sprayed in through a ring of nozzles and ignited. That chemical reaction gives off a lot of heat.

So the temperature jumps to around 1,500° C. So now you've got this high pressure gas from the combuster that just wants to expand. And now it's got an incredible amount of thermal energy. But between the combustion chamber and the outside air is this rows of turbine blades.

So in order for the gas to expand and get out, it needs to push these turbine blades out of the way. And in pushing the blades, that is how it transfers its energy to the engine. This is where all the power really comes from. In modern jets, on takeoff, each high-pressure turbine blade is generating as much power as a Formula 1 car.

And there are 68 of them. As the gas rushes through the turbine and nozzle, its pressure drops from around 50 atmospheres down to one, and it expands by almost 20 times. And that spins these turbine blades up to 12,500 revolutions per minute. The fan that is pushing all that air backward and ...