Novel methods for propelling a rocket

Discussion in 'Physics & Math' started by Rocket Paul, Sep 23, 2017.

  1. Baldeee Valued Senior Member

    Messages:
    1,104
    The magnet does not provide direct lift to the top of the rocket.
    It merely transfers the thrust from the engine which is still at the bottom.
    But then a rigid steel beam does that as well.
    So nothing new,
    You'd probably find 100 miles at 100mph is far more efficient: higher gear etc.
    But that aside, you still haven't explained where you think the additional thrust comes from, rather than it just being a transfer through the magnets.

    Hint: there is no spoon.
     
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  3. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Got any actual figures for that?
    The rocket still has to move the entire weight of the vehicle.
    At slower speeds it's applying the thrust for longer (= more fuel usage) - and also applying it for longer in the lower atmosphere, thus in a denser medium where drag is higher (more thrust required) AND where the engine itself is (significantly) less efficient (= even more fuel being used).
     
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  5. Rocket Paul Registered Member

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    56
    Yes lets say action on the fixed magnet and reaction on the free moving engine if the engine is not fixed then the reaction is nullified against the craft, I totally agree there is reaction on the free moving engine but like I say free moving.
    Yes the engine takes all the mass but is it not applying energy to the front of the craft as well as the back nothing is for free in the system if it was we would not need the engine.
    Yikes lets also ask do we have a re-actionless drive ?? we know the engine does have reaction from the fixed magnet but the craft does not, it only has action on the fixed magnet and because the engine is free moving not fixed can we not call it an independent energy force, inside the craft but not fixed.
     
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  7. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    No.

    Wrong.

    Sheer nonsense.

    Wrong again.
    Once in motion the engine is not "free moving" since it must reach a stop limit (effectively becoming "fixed") in order to start to move the front of the craft. The entire system relies on action/ reaction and the ONLY thing your "idea" has done is add unnecessary mass and complication.
     
  8. Rocket Paul Registered Member

    Messages:
    56
    Yes sure effectively it becomes fixed like you say when it "pushes at the front of the craft" so we agree we are pushing from the front as well as the back.
    Yes there is reaction to the engine but if you push the engine back reaction its just moving down the guide rails so no force applied to the system maybe a bit of drag.
     
  9. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    Since the exhaust is at the back then that's where the "push" is from.

    Wrong again.
    The thing is a system - regardless of the internal (and extraneous) detail: it's no different (at all) in function from any other rocket.
     
  10. Rocket Paul Registered Member

    Messages:
    56
    Yes the initial thrust does come from the back the engine, lets do a simple test get a three foot length of pipe sealed at one end and get a four foot stick rest the pipe sealed end upwards on to the open end of pipe and try and lift the pipe upwards, yep its kind of a balancing act unbalanced now put the stick inside the pipe up to the sealed end facing upwards and now the pipe is more balanced, with your hand acting as the free moving engine lifting the pipe the same as the free moving engine, we now have force at the bottom and the top its nothing like what we have now.
     
  11. Kittamaru Now nearly 40 pounds lighter. Staff Member

    Messages:
    13,219
    No, the only thrust comes from the engine... the magnets do nothing of value at all.

    Your hand is not akin to the "free floating engine" you describe - for one, your hand is anchored to your body, and through that, to the ground.
     
  12. Rocket Paul Registered Member

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    56
    Okay throw the stick so its free floating in to the pipe.
    The magnets are only there to provide a cushion to stop the inner engine colliding with the craft, if anything else comes from the magnets or spring or steel bar then that's a bonus.
    I think what is confusing some is that the engine is creating forward force lift and no reaction to the craft, I agree that there is reaction to the engine but the engine is not attached to the craft only in forward action.
    Another test light a firework rocket and put a plastic cylinder around the rocket, yes all will fly force to the front of the cylinder and force from the back of the rocket.
     
    Last edited: Oct 19, 2017
  13. Baldeee Valued Senior Member

    Messages:
    1,104
    Has this thread just been some sort of elaborate wind-up??
     
  14. Kittamaru Now nearly 40 pounds lighter. Staff Member

    Messages:
    13,219
    Stability of an aerodynamic object isn't that simple...

    Plus, then, you have to figure in what happens once you are out of the atmosphere and how handling changes them.

    This is why rockets employ gimbal engines, maneuvering thrusters, and sometimes aerodynamic planes... all of which is more effective, and less costly (both in terms of weight and money) than what you are proposing.
     
  15. Rocket Paul Registered Member

    Messages:
    56
    Guys I am stunned at the responses I am trying to answer from all angles yet some replies seem totally irrelevant, the tests I suggest all come up trumps all be it just rough examples, I guess as soon as anyone mentions magnets its a no no but before I go I will leave you with this.....
    For years people have tried to make magnet propulsion systems work off one structure but all have failed because of equal reaction, yet here we can overcome reaction, so I have let the cat out of the bag and do expect a lot more egg in the face not sure I want to read it when we can't even agree the rocket will work.

    Can anyone say that face to face repelling magnets will not bring a steady increase in momentum to a craft if reaction is nullified, its never been proven or disproved, a constant force in one direction and nullified in the opposite direction.
     
    Last edited: Oct 19, 2017
  16. billvon Valued Senior Member

    Messages:
    12,757
    Because:

    1) Friction between the exhaust plume and the rocket body reduces specific impulse, thereby requiring more fuel for a given mission
    2) Heating from the plume would increase heat shielding requirements, adding weight and thereby requiring more fuel for a given mission

    However, it does work; the Apollo escape tower rockets "did it from the front" (but were, fortunately, rarely used.)
     
  17. billvon Valued Senior Member

    Messages:
    12,757
    Face to face repelling magnets will provide a one time impulse to a vehicle which will NOT be steady; it will rapidly decline to zero. It might be useful to facilitate stage separation or something, but that's about it.
     
  18. Baldeee Valued Senior Member

    Messages:
    1,104
    How are you proposing to nullify the reaction?
    You push the lower magnet toward the upper with force F and the upper magnet moves away from it with force F.
    It's no more complicated than that.

    How has this discussion managed to go on for so long??
     
  19. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    18,629
    The confusion here is entirely yours. (And there is - MUST be - a "reaction to the craft": otherwise it wouldn't move - plus, as you've already been informed, you're misusing the word "lift").
    For example:
    So what?
    Again, there is no more "force to the front" than there is on a standard rocket. If the exhaust is at the back the force is applied at the back.
    Absolute drivel.
    The only reason this thread has continued so long is that everyone (except you) has said that "face to face repelling magnets will not bring a steady increase in momentum". (Basic physics "disproves" it).
    And the force is NOT "nullified" in any direction.
    Partial list:
    1) To make sure that the vehicle's structure is not inside the exhaust plume the rocket nozzles must be directed at least partially sideways - this will mean a loss of direct upwards thrust necessitating more powerful (and heavier) engines.
    2) Your method also requires multiple exhaust nozzles if not multiple engines in order to balance side forces. Any out-of-balance thrust would require more control force than is needed on an exhaust-at-the-back vehicle.
    3) Your method also requires placing the heavy engines at the top/ front - meaning that the entire structure has to be stronger in order to support that weight before lift off.
     
  20. DaveC426913 Valued Senior Member

    Messages:
    6,987
    To set the record straight: None of your respondents here are confused.
    Most of us of us have, at some point, run into someone (or somemany) flogging "let's use magnets as propulsion" fallacy.
    It's not a new idea by a long shot.

    We know how Newton's Laws works, in general, and free propulsion craft in specific.

    What we're doing here is guiding you toward seeing the errors in the mechanics for yourself.
     
  21. ArafuraOpal Registered Member

    Messages:
    20
    Magnets could be used to act against the Earth's magnetic field so the craft is repulsed by the Earth's magnetic field. The magnets would have to be so strong that it becomes mechanically impossible to do so. Also, if the magnets are just slightly out, the space craft would upend itself to be attracted by the the Earth's magnetic field causing it to crash. Also in space the magnetic fields are much weaker, practically non-existant, so this would not be able to used for anything other than leaving a planet with a strong magnetic field.
    Sorry, this would be wrong for the Earth, the Earth's magnetic field is not strong enough for any magnet to overcome the gravitational pull.
     
    Last edited: Oct 21, 2017
  22. Rocket Paul Registered Member

    Messages:
    56
    Hello guys lets talk about the magnets, if you do another simple test by fixing a magnet to the back of a toy car on a smooth flaw and hold a repelling magnet in your hand move your hand towards the car and it will push it in to motion this is because we are pushing off two different platforms in fact my guess is you will have a job to keep up with it unless you move your hand faster, just the same as craft and engine I mention, okay the engine is inside the craft but its not fixed to the craft its been blasted up the guide rails and is now an independent platform just like the hand held magnet on the car, the fixed magnet action to the craft and reaction is on the second platform the engine, although the engine makes everything work it is not fixed to the craft only in forward motion, it will not slow down or only last a short while this would only happen if you ran out of fuel or repelling distance (spent energy) same as if a compressed spring stays compressed then its producing energy.

    Lets also go back to the rocket sketch.....
    1, A rocket could take off from guide rails feasible...
    2,A rocket could have an outer skin the same as I describe and still take off feasible..
    3.So we have two platforms to push and push off craft and free moving rocket feasible..
    4.We have two types of energy engine and magnets feasible...
    5, so in fact all what I say is feasible..

    On the diagram it could be said that the overall mass is greater but lets not forget that the rocket craft could be made a lot smaller if it had to carry less fuel needed to escape earths gravity, in fact you could take in to orbit most shaped balanced craft by adjusting the design so the free moving magnet connects to a number of repelling magnets at each corner of lets say a triangle shape.

    Here is the link to the diagram just in case anyone missed it..
    http://magjet.blogspot.co.uk/
     
  23. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

    Messages:
    18,629
    No.

    This is the problem in a nutshell: you're guessing and not looking at the physics.

    No.

    No.

    No.

    No.

    Since (with all the additional crap) it masses more than a standard rocket then it would need more fuel

    Pure drivel.
     

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