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Jet engine

  1. Feb 21, 2008 #1
    O.k i understand that a jet engine gains its thrust by pushing heated air out its nozzel, but i was wondering if that the reason it goes forward is because the speed of it being released out the rear nozzel is moving faster than the air can get pushed out of the way so the some of the force is used to push air out the way, and the remaining is used pushing the jet forward
    is this correct?
  2. jcsd
  3. Feb 21, 2008 #2


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    No it's a lot simpler than that.
    Consider a rocket engine (it's a little simpler )
    You burn fuel in a closed box , the fuel creates hot gas which expands pushing on all the walls of the box equally - so no movement.
    Now make a hole in the back of the box, the hot gas at the back doesn't push on this any more, but there is still gas pushing on the front of the box - so the box moves forward. This is why rockets can work without atmosphere.

    A jet engine is basically the same except that instead of storing the oxygen it pulls it in from the air at the front. Instead of pushing on the front of the rocket chamber the hot gas is pushing on the back of the compressor blades.
  4. Feb 21, 2008 #3
    Thanks very much that explains alot :), your a star
  5. Feb 21, 2008 #4


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    A white dwarf, to be specific... :uhh:

    Okay, I'm leaving now.
  6. Feb 21, 2008 #5


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    I prefer to think of myself as 5' 6 1/2" of slightly degenerate matter
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