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Aero engine without gas turbine

  1. Feb 18, 2007 #1
    Is there any aero engine in the world without any rotating bodies like compressor-turbine? Other than ram jet or scramjet.

    Thers is a vague idea in my mind to go for an aero engine without rotating elements in it. I just wanted to confirm if it is there.
     
  2. jcsd
  3. Feb 18, 2007 #2

    brewnog

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    Well a normal reciprocating engine doesn't have a compressor or turbine, but still has rotating components (crankshaft etc). A 2 stroke radial engine would minimise rotating components, but you've still got the prop shaft which needs to rotate. A rocket engine doesn't have any rotating components.

    What are you trying to do?
     
  4. Feb 18, 2007 #3
    IC engine has its rotating parts. and Rockets are coming in ramjet or scramjet category which is known to me.
    My question here is "is there any aeroengine without even single roating element in the main power unit (other than accessory gears and accessories)?
     
  5. Feb 18, 2007 #4

    brewnog

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    None that I know of, but you should look at how a radial engine works, there's a nice distinction between that and a normal reciprocating engine at the crankshaft.

    Why do you ask?
     
  6. Feb 18, 2007 #5
    The reason of asking this question is there are hell lot of problems by having any reciprocating or rotating parts in the engine in terms of play, vibration, manufacturing, cost etc etc. So it is better to go for an aeroengine without any such moving parts. There is a vague idea in my mind and seems to be its feasible too. So i wanted to confirm is there any engine exists in the world without any rotating parts or moving parts.

    Hope you got your answer!

    That idea - I will share later some days if you insists.
     
  7. Feb 18, 2007 #6

    FredGarvin

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    Pulsejet, ramjet and rocket engines are the only ones that come to my mind.
     
  8. Feb 18, 2007 #7

    brewnog

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    That's a pretty bold statement to assert, particularly given the fact that all aeronautical vehicles actually use engines with rotating components!

    What's your idea, we might be able to help you understand any limitations of it.
     
  9. Feb 19, 2007 #8
    I ll share you the idea some days later. Please wait.
     
  10. Feb 19, 2007 #9
    Without revealing the patent that will put you alongside Whittle, what is your means of thrust. You seem to be implying that you are not using a rotating prop to pull the aircraft through the air, or a gas thrust to push it. Apart from flapping wings I'm not aware of any other methods.
    Give us a peek under the tarpaulin, I'm sure I'm not the only one intrigued.
     
  11. Feb 19, 2007 #10
    Yes, Mr.Panda,
    Its getting thrust from an engine but without rotating of sliding/moving parts in the engine. But its not scramjet, because it could be put into opeartion when Aircraft is moving at sonic velocity only and hence it could not take off from ground.
    In aero engine, compressors are used to raise the pressure and increase the mass flow rate of air which engine sucks. then compressor needs power which is given by a turbine... and it forms a mesh of rotating components and leading to lot of manufacturing and opeartional problems ... ofcourse the whole world is using turbo jet engines only. however to come out the problems and without sacrificing heavy massflow rate induction in engine, we can use one system that is what my idea is.
    for the time being i give a clue..."Ejector". I am into this project now once things are feasible i will tell you about the whole mechanism....
    till then please bear with me if you are much intrested in knowing the answer.
     
  12. Feb 19, 2007 #11
    Its getting thrust from an engine but without rotating of sliding/moving parts in the engine. But its not scramjet, because it could be put into opeartion when Aircraft is moving at sonic velocity only and hence it could not take off from ground.
    In aero engine, compressors are used to raise the pressure and increase the mass flow rate of air which engine sucks. then compressor needs power which is given by a turbine... and it forms a mesh of rotating components and leading to lot of manufacturing and opeartional problems ... ofcourse the whole world is using turbo jet engines only. however to come out the problems and without sacrificing heavy massflow rate induction in engine, we can use one system that is what my idea is.
    for the time being i give a clue..."Ejector". I am into this project now once things are feasible i will tell you about the whole mechanism....
    till then please bear with me if you are much intrested in knowing the answer.
     
  13. Feb 19, 2007 #12
    Its getting thrust from an engine but without rotating of sliding/moving parts in the engine. But its not scramjet, because it could be put into opeartion when Aircraft is moving at sonic velocity only and hence it could not take off from ground.
    In aero engine, compressors are used to raise the pressure and increase the mass flow rate of air which engine sucks. then compressor needs power which is given by a turbine... and it forms a mesh of rotating components and leading to lot of manufacturing and opeartional problems ... ofcourse the whole world is using turbo jet engines only. however to come out the problems and without sacrificing heavy massflow rate induction in engine, we can use one system that is what my idea is.
    for the time being i give a clue..."Ejector". I am into this project now once things are feasible i will tell you about the whole mechanism....
    till then please bear with me if you are much intrested in knowing the answer.
     
  14. Feb 19, 2007 #13

    russ_watters

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    Well, it sounds like a ramjet. We did have someone here once try to eliminate the compression stage of a jet engine, though. I hope that isn't what you are trying to do...
     
  15. Feb 19, 2007 #14
    May be similar but its not ramjet alone. because ramjet just receives ram-air as is without compressing it before entering into combustion chamber.

    The rear portion of my engine may have ramjet similarity but not the intake and compression portion. Its totally new.
     
  16. Feb 19, 2007 #15

    brewnog

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    Well I'm sure then, given your extensive knowledge of existing designs, that it's definitely something which Rolls Royce, GE or Pratt & Whitney have never thought of.

    Russ, I thought of exactly the same thread!
     
  17. Feb 19, 2007 #16

    russ_watters

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    That isn't true! Yikes!

    http://en.wikipedia.org/wiki/Ramjet
     
  18. Feb 19, 2007 #17

    FredGarvin

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    I cringed when I saw the hint of an ejector on this. I know where this is going...
     
  19. Feb 20, 2007 #18
    Its good that you got something from hint. Is it feasible? Yes it is. because NASA is also into similar (not the same of mine) kind of system which is under experiment.
     
  20. Feb 20, 2007 #19
    We are getting somewhere now, you have a jet with a non-rotary compressor that does not rely on forward thrust to provide compression.

    So in answer to your question, yes I have heard of such a system, it's the pulse jet, although it does not provide continuous thrust.

    The power to weight ration of modern gas turbines are pretty high so I'm not sure you would be able to gain that much by removing the incredibly well balanced low friction moving parts of a commercial engine. Unless you are trying to achieve hypersonic speeds without using RAM and SCRAM technology.
     
  21. Feb 20, 2007 #20

    FredGarvin

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    Under research and feasable are two totally different worlds. Ejectors have been around a long time. Also, most of the ejectors I have ever seen are, like Panda already mentioned, attached to pulse jets for thrust augmentation. The SR-71 had an ejector set up to give more thrust. What would be different in your application? Also, in regards to something else Panda mentioned, when we manufacture an engine, vibrations are not the biggest concern with a properly operating engine. We have our overall levels down quite a bit and they are nowhere near a recip engine's. Noise is also improved dramatically with various mixing schemes and materials.
     
    Last edited: Feb 20, 2007
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