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Forward Acting Thrust

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Old 31st May 2012 | 20:57
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From: Altrincham
Forward Acting Thrust

In How Airliners Fly it shows the workings of a jet engine and states:

"The fan, which is encased in a cowling, forces the compressed air backwards in the form of a jet, much in the form of a domestic electric fan. The engine itself experiences an equal and opposite force and this is the forward acting thrust which propels the aircraft".


If the thrust is coming out forward from the engine, how come the aircraft still flies forwards?
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Old 31st May 2012 | 21:18
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Newtons 3rd (I think) law of motion.

For every action there is an equal and opposite reaction.

Propel a mass of air rearwards and the resultant force (thrust) is forward.

Simples.
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Old 31st May 2012 | 21:53
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If the thrust is coming out forward from the engine, how come the aircraft still flies forwards?
Read "How Airliners Fly" again. What they are saying is the air expelled from the engine is going backwards, but the thrust (i.e. the force) produced by the engine is acting in a forwards direction, i.e. it's pushing the aircraft forwards.

Last edited by wiggy; 31st May 2012 at 21:53.
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Old 31st May 2012 | 23:11
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By pushing all that air through the engine rearwards, the engine sucks it way forwards
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Old 1st June 2012 | 09:58
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I will do

Thanks all for your patience and replies, I get it now
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Old 1st June 2012 | 10:30
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Although the action of producing thrust does produce a rearward force in the engine!
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Old 1st June 2012 | 11:29
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Isn't there a bloody big vacuum in front of the engine...?
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Old 8th June 2012 | 16:10
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Although the action of producing thrust does produce a rearward force in the
engine!
Not so I'm afraid.

The compressors and the diffuser section, amongst others, produce forward thrust. The turbine section produces a rearwards force.

Last edited by Lightning Mate; 8th June 2012 at 17:30.
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Old 8th June 2012 | 17:29
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This should help your understanding.......

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Old 8th June 2012 | 22:17
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Should have a Reply With Quote Button on here but anyway


So the total forward gas load less the rearward gas load produces total forward thrust?

Last edited by donnlass; 8th June 2012 at 22:18.
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Old 8th June 2012 | 23:27
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Although the action of producing thrust does produce a rearward force in the
engine!
Originally Posted by Lightning Mate
Not so I'm afraid.

The compressors and the diffuser section, amongst others, produce forward thrust. The turbine section produces a rearwards force.
So it does then...Unless I missed the bit where my turbine isn't in my engine

Last edited by Lord Spandex Masher; 8th June 2012 at 23:28.
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Old 10th June 2012 | 15:18
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So the total forward gas load less the rearward gas load produces total forward
thrust?
Well, if you think I am incorrect, check the Rolls Royce book, upon which my diagram above is based.

If you think it's wrong, then please feel free to put Rolls Royce on the right track!!!!
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Old 10th June 2012 | 18:58
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No I dont think you're wrong at all, am not qualified to think that
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