How a High Bypass Turbofan Works

DFAN Aero 315 Course Video from the United States Air Force Academy

[@miri6056]

By far the best airline engine video I’ve seen

[@nurlatifahmohdnor8939]

B-Y signal

[@EASYTIGER10]

Basically a high bypass turbofan is a ducted propeller with a small jet engine in the middle

[@SurfingBullDog]

I had no idea the bypass air provides the majority of the thrust

[@MrOneWorld123]

Now I see why jet engines take their time to power up

[@eriklee1794]

Suck squish ignite blow......this was a highly informative video

[@FPV-wi8fw]

Great explanation 👍

[@alexanderlayouni7301]

Thanks for explanation! best video ever

[@DrPhilby]

The best explanation

[@taleimoce973]

Great vid!

[@Notolecimy]

Briliiant video!

[@DanFrederiksen]

Dat video quality doe

[@strangedays4]

Excellent video although I'd like to know more about the by-pass air which produces 80% of the thrust

[@paulh2981]

If I understand it correctly, the turbine engine spins the huge propeller blades in the front of the engine. Most (80%) of that air bypasses the engine and is compressed by the restrictive ducting, so it shoots highly compressed air out the back, increasing the amount of thrust per unit of fuel used dramatically.

[@El_Chompo]

What happened was first they made jet engines. Then they added propellers on the end and found out these were more efficient. And then they put ducts around the fans they added on the end, which makes them even more efficient. So that's where 80% bypass air comes from. The actual jet engine part is only being used as the most efficient way to burn fuel and turn it into power to turn a fan blade to propel you, it's not really being used to make forward thrust itself so much.

[@Hazztech]

@@paulh2981 so these are just weird looking prop planes...

[@MoistGrundle2.0]

​@@HazztechEssentially. It's an insane prop, with a cowl that increases efficiency and thrust, and a lot of complex doodads inside to make it all work.

[@paulh2981]

My main takeaways from thie: the only way to propel yourself in a fluid (such as air) is to push against the fluid. Pushing against the fluid propels the vehicle in the opposite direction, which is called thrust. Jet engines compress air before pushing it out, to increase the push in order to provide more thrust. They do this with propeller blades and combustion combined with restrictive ducting.

[@jirehla-ab1671]

What would happen if it didn't eject any fuel?

[@eriklee1794]

Where do we draw the line on it just becoming a big ass turbo prop....minus the gears

[@rontate7719]

more quite?

[@privatejr2702]

so how is the fan in the front initially powered before enough air can be compressed?

[@simonpohludka1002]

The APU in the back of the aircraft actually spin the fan. The fan then suck air and that's it

[@myusername3689]

@@simonpohludka1002 Yup APU is a small turbine engine that’s light enough to spin on electricity alone.

[@lenynaise]

@@myusername3689 The APU also uses fuel

[@JohnPlant90]

The APU produces electricity and compressed air. ​@@myusername3689

[@GRJ1SwagY]

call me an absolute idiot. but just a thought. why dont they use a simple ICU like the ones in a sedan? like use it to turn the turbines and push the air backwards! did he not say that 80% thrust comes from bypassed air? hope someone will help me out with this doubt!

[@SayanChakraborty_F1]

If they use only fuel then the amount of fuel required will be much higher compared to the current case. In this scenario they are using the compressed air to a large extent to help rotate the low spool which in turn rotates the propeller.

[@shriramvenu]

gas turbine engines, which is what the turbojet component basically is, are far more efficient at producing high speed rotation compared to reciprocating piston engines. Lighter and fewer moving parts too.

[@gusm5128]

Basically just a ducted fan .

[@philknight8808]

Understandible some what . But what's involved in overhauling the enjine

[@philknight8808]

???

[@philknight8808]

Give us ' in detail of what's all involved when joverhauling the turbofan engine

[@JB-ef6wt]

This is one of the better videos on how a turbofan engine works. Also see: kzbin.info/www/bejne/lX3EfJ97Z81mgNk

[@rozniyusof2859]

I thought jet engines work with Newton's Third Law, rather than the Second.

[@julians7058]

Its both. The one shown here is the second law F=ma. And now the third comes into play, every force has a counterforce. So without the explanation of the second law you couldnt explain the third because you wouldnt know about the force.

[@nurlatifahmohdnor8939]

Page 157 See ducted fan.

[@nurlatifahmohdnor8939]

Page 157 Birmingham Wire Gauge