What does thrust in jet engines push?

Question

I know that air gets compressed and is lit to make thrust but what actually gets pushed by the thrust? The engine as a whole or are there certain parts ment to absorb the thrust, thus pushing the aircraft? I feel like the thrust should just thrust itself through the front of the engine and defeat the purose of the engine. Is there a dynamic equilibrium between the fan blades and the thrust and is there something to recieve the enegry and push the plane? I love aviation and one day hope to be a test pilot but I have always been puzzeled on what jet engines actually push because its not like a propeller that pulls.

Answer 1

The rearward jet pushes forward against the combustion chamber.  

The air accelerated aft by the bypass fan pushes forward against the fan blades.

Answer 2

Lamens...Newtons Third Law. If there is a force one way..there is a force equal and opposite the other

Answer 3

The jet engines push and pull the air and push exhaust gases in order to create thrust. However, it does not push on the surrounding atmosphere; it's only there to provide lift and oxygen.

Imagine you're sitting in a rolling chair with a basket of baseballs. If you throw the baseball, it goes one direction, and you go the opposite direction. If you throw hundreds of baseballs, then you'll get going pretty fast. This is basically how the jet engine works. It does not push on the surrounding air.

When air enters the turbofan engine, it goes to two different distinct areas, the bypass area and the jet area.

The bypass area is exactly what it sounds like; air goes around the jet area and out the back.

You're probably thinking, what's the point?

Well A turbofan is essentially a jet engine, with a fan mounted at the front. This is similar to a propeller on other aircraft. The fan uses energy from the jet engine to move a larger amount of air more slowly, which increases fuel efficiency below mach 2.

Remember, as the fan gets bigger, it has to turn slower to move the larger amount of air, but the output of energy should be the same right?

Not exactly, it takes more energy to move a small amount of air very fast than it takes to move a large amount of air relatively slow, due to friction forces.

As for the air entering the jet area, it goes through a series of compressor blades which compresses the air, and as a result, heats up the air tremendously.

Then this heated air goes to what is called the "flame holder". This is where jet fuel is basically injected into the engine, and the hot air spontaneously reacts with the jet fuel and combusts.

This combusted air travels to the back of the jet engine where a series of exhaust blades capture the energy of the escaping gases and drive the fan in front, and the compressor blades. Some of it escapes past the exhaust blades and add to the total thrust.

All the blades of the engine are connected to one axis, and the exhaust blades basically sustain the jet engine.

Answer 4

When the blade of the turbojet engine starts turning, there is a pull which pushes the engine forward which results in a ramming effect which in turn compresses the air,(air gets compressed both by ramming effect and due to the blades pushing it into a small area). this compressed air which is now hot due to work which was done on it, is cooled and then pushed in to the combustion chamber where the fuel is burnt(oxygen comes from the compressed air). due to the combustion of fuel, suddenly the volume of gas increases.the only outlet would be from the behind because while this was happening fresh compressed air has already entered from the front and the pressure at the rear is lower than in side the combustion chamber. The gas bursts out of the rear creating a forward thrust (newton's 3rd law). the gas to be able to move back actually pushes the engine forward. not only that the escaping gases turn the turbine which in turn turns the compressor blades which in turn not only sucks air but also compresses!

Answer 5

A jet engine does not push against anything.  It's not like traveling through the water where your hands and legs push against the fluid.  

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For every action there is an equal and opposite reaction.  If you sit in a chair that has wheels and you hold a heavy object, if you then throw the heavy object away the chair will roll backwards.  In a jet aircraft the engine thrust is expelled out the back of the engine at high speed causing the plane to move forward.

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This is one of the basic laws of motion.  It works just as well in space where there is a total vacuum and no air at all.

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Answer 6

suck, squeeze, bang, blow.

On modern commercial hi-bypass engines 80% of the thrust is produced by the fan blade, the engine core's main purpose is to turn the fan. The fan compresses the air which is converged down the exhaust increasing in velocity producing thrust. As previous people have said the air goes backwards the opposite effect is the engine moving forwards which inturn pulls the aircraft.

Answer 7

how did you hang up  the carpet with duck tape???

Answer 8

De plane, de plane, de plane gets pushed by thrust.

Answer 9

a jet engine creates more of pushing force than a pulling force. in the first part of a jet engine there are stators and rotors. both are at an off-set angle and when the rotors pass in front of the stators they compress the air. there are several stators and rotors in a jet engine which continue to compress the air tighter and tighter until it reaches the combustion chamber. this is where fuel is added to the mixture. the mixture is ingnited and the blows through another section of the engine called the turbine section, this is basically another section of stators and rotors, the exhaust gets compressed and gets forced out the exhaust section. it most aircraft( dont do this when the engines are running) if you look at the exhaust of a jet engine you will notice a cone. this acts much like a wing of an airplane. the cone causes the exhaust to flow much more rapidly out the back. if the cone wasn't there you would not get any thrust whatsoever. i guess you could call the cone a "concentrator" if you contact a jet engine mechanic they may be able to explain it better than i can

Answer 10

Basically it pushes the engine in the opposite direction of the jet blast.  And the engine is connected to the air plane.

More specifically the jet turbine blades are the parts that is getting pushed - which is connected to the engine.

Good Luck...

Answer 11

It sucks!  Just like a sail boat, it's not the wind in the back it's the low pressure in the front.  That's why engine power is measured as EPR. Exhaust Pressure Ratio.  http://www.grc.nasa.gov/WWW/K-12/airplan...

Now mind you I've been out of the cockpit for more than thirty years but I remember these basics.  So it makes you wonder where these self proclaimed experts get their knowledge.  They think self proclamation, emulation, supersedes factual reference.  I know I can be wrong that's why if the question is interesting I will back it up.

And we call it thrust because that's easier to measure than vacuum.  Thrust is, http://www.grc.nasa.gov/WWW/K-12/airplan...

Suck is equal and opposite.

BTW: Rockets work on thrust because the opposite reaction is pushing on the front of the chamber. equals forward speed.  You can delay a jet in the first moments of power but don't get in the way of a rocket.

Note: JThe argument of push or pull is an old topic and the power is referred to as 'Thrust'.  This is more obvious on sailboats that are also pulled rather than pushed. Jet fighters with After Burner produce Thrust.  This is done by reducing the nozzle and injecting fuel in the not exhaust. It's almost the same as a basic ramjet.

The fan's on a Fan Jets act as shrouded Propellers to provide low altitude Power, 'thrust' where the jet is less efficient.  That's why a 707 has such a long take off roll by comparison.

Answer 12

Isn't thrust the force generated by the spinning blades and fuel combustion that pushes the airframe forward.

Answer 13

It pushes the expanded hot air out the back. It takes force to do that. More exactly, it takes force to accelerate the air, i.e. speed it up by a large amount.

The propulsion does not come from that air pushing on anything, it comes from the reaction force -- a jet or rocket is a 'reaction engine." The term refers to Newton's Third Law: For every action there is an equal and opposite reaction."

Forces always come in pairs. The jet engine uses the exact same principle as the octopus; it fills a sac with water, then squeezes it, and water shoots out in one direction, the animal goes the other direction.

All this is why such engines can operate in space, where there is no air; in fact, they work even better there than in an atmosphere.

Answer 14

Newtons Third Law of Motion - "Each action has an equal and opposite reaction".

Jet engines suck the air from the intake, compress it, mix it with fuel and ignite it. This results in a high velocity air being pushed out from the exhaust. Air being pushed back and out from the exhaust makes the engine (and plane) move in the opposite direction - front.

The engine itself receives the energy from fuel and combustion which is translated into forward motion of the aircraft.

A good and intelligent question.