Novel methods for propelling a rocket

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

  1. exchemist Valued Senior Member

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    6,465
    OK well it won't do that and I have just explained why. The guide rails and the magnets, or spring, or rubber cushion, between them make it a single rigid body, once the slack is taken up.

    There is nothing "free-moving" and it will consequently topple like any bottom thrust rocket.

    Sorry, but there it is.
     
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  3. Rocket Paul Registered Member

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    Okay I am off to bed now but I will answer your question why use magnets......if you now have a better idea on how the system works then when the engine takes the mass and starts to lift the craft and control the thrust on the engine we can move as slow as you like when the craft is levitated between magnetic fields and magnet platforms, the magnets also act as a cushion stopper between platforms.
     
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  5. Kittamaru Now nearly 40 pounds lighter. Staff Member

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    Most veering isn't because of being pushed from the rear though. This change doesn't solve any issue that exists.
     
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  7. Rocket Paul Registered Member

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    How can the system topple when we are moving vertical you say the mass but all thrust is vertical, one of the reasons today's rocket has to travel so fast because they are unbalanced top heavy and thrusting from the bottom, with lift from top and bottom all is fine.
     
  8. Rocket Paul Registered Member

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    Guys I really think you are moving away from the theory how to lift a rocket from the top I really don't care if unleaded is better..see you tomorrow.
     
  9. billvon Valued Senior Member

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    ?? I think you are perhaps unaware of the goal of a rocket.

    The goal of a rocket is to go fast. That is its #1 job - to accelerate a payload hard enough and long enough to put it into orbit, which means you have to make it go very, very, very fast. At LEAST 17,500 miles per hour fast. That is very fast. That's why you need high specific impulse engines, and multiple stages, and high energy fuels. Because you have to go very fast.

    A rocket that does NOT travel fast is useless for purposes of launching spacecraft. It is not "all fine." It is useless.

    In addition, you are confusing what happens when you hold something in your hand vs when it is free to move (i.e. has left the surface of the Earth.) Once it's left the surface of the Earth, it doesn't matter where you push on it. If you push on the front of a rocket with a force exactly in a line with its center of gravity, it will not turn - it will accelerate in a straight line. If you push on the back of a rocket with a force exactly in a line with its center of gravity, it will not turn - it will accelerate in a straight line. If you push on the front of a rocket with a side force, it will turn depending on how much force you apply, the lever arm and the rotational inertia of the rocket. If you push on the back of a rocket with a side force, it will turn depending on how much force you apply, the lever arm and the rotational inertia of the rocket.

    It is exactly the same physics in both cases.

    What you experience when you stick a pipe inside another pipe and hold it in your hand has nothing - zero - zip - nada to do with what a free-flight rocket experiences.
    You realize you are answering yourself here, right?
     
  10. Kittamaru Now nearly 40 pounds lighter. Staff Member

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    ... Rocket Paul, try this with a model hobby rocket and report back to us.
     
  11. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    One more time: you were given reasons (way back in one my first posts in this thread).
    But, as usual, you appear to have ignored them.
    Apart from that - YOU have made numerous claims without providing any supporting reason (or science).

    1) If the "two craft" are connected magnetically then they may as well be connected mechanically.
    2) The rocket has to be sufficiently powerful to lift the entire weight (of "both" craft) if it's not strong enough to do so the the magnet will simply repel the "rocket part" downwards and no overall movement will take place.

    The sequence of operation is as follows:
    The "two craft" are sat on the launch pad. The "top one" - due to its mass - is already very close to the absolute minimum distance (i.e. the "magnetic connection" is compressed) from the"bottom one".
    The rocket motor ignites and starts to lift the "bottom one", there will be some small reduction in the separation between the "two craft" until the thrust from the rocket is sufficient to lift the total mass of the "two craft".
    Since the rocket motor is accelerating then the "top craft" cannot lift (magnetically) any further away from the "bottom one".
    Once the vehicle is in orbit the rocket motor stops thrusting and the magnetic compression relaxes (again, this does not provide any significant thrust to the "top craft" because that relaxation will move BOTH "top" and "bottom" craft (one forwards, one backwards) "equally" (with regard to their relative masses).

    Here's a suggestion: go back to your "experiment" but this time do it with a loaded cart and see how much it moves when you hold a magnet in your hand close to it.
     
  12. Rocket Paul Registered Member

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    Billvon
    I think you are not taking any notice of the concept.....the very reason for the concept and two platforms is so you don't have to move at least 17,500 mph with the conventual rocket today yes you have to move that fast to escape earths gravity when all the propelling force is at the back if you go slower then it topples (unbalanced).

    So sorry I have not got a real rocket I think they cost a few bob yes it is exactly the same in both cases but who wants to turn it.
     
  13. Rocket Paul Registered Member

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    56
    1) If the "two craft" are connected magnetically then they may as well be connected mechanically.
    2) The rocket has to be sufficiently powerful to lift the entire weight (of "both" craft) if it's not strong enough to do so the the magnet will simply repel the "rocket part" downwards and no overall movement will take place.

    The sequence of operation is as follows:
    The "two craft" are sat on the launch pad. The "top one" - due to its mass - is already very close to the absolute minimum distance (i.e. the "magnetic connection" is compressed) from the"bottom one".
    The rocket motor ignites and starts to lift the "bottom one", there will be some small reduction in the separation between the "two craft" until the thrust from the rocket is sufficient to lift the total mass of the "two craft".
    Since the rocket motor is accelerating then the "top craft" cannot lift (magnetically) any further away from the "bottom one".
    Once the vehicle is in orbit the rocket motor stops thrusting and the magnetic compression relaxes (again, this does not provide any significant thrust to the "top craft" because that relaxation will move BOTH "top" and "bottom" craft (one forwards, one backwards) "equally" (with regard to their relative masses).

    Here's a suggestion: go back to your "experiment" but this time do it with a loaded cart and see how much it moves when you hold a magnet in your hand close to it.
    Dywyddyr
    Can it be you who is doing the ignoring.
    1) one craft two platforms something you fail to admit.
    2) yes we know the rocket has to be powerful to lift the entire mass of both craft you say, do you mean 1 craft and two platforms it will be strong enough, do you think by adding two magnets and a few guide rails that the rocket is overloaded, so you agree two platforms the rocket part goes downwards.

    the sequence of operation as you say I totally agree the thrust of the rocket will lift both craft and two platforms and yes since the rocket motor is accelerating the top platform is compressed and compress two repelling magnets together then the magnetic repelling field gets stronger but yes it can not move away any further but we still have force top and bottom of the craft, yep if the motor stops thrusting once in orbit the whole system is without drive but who says we stop the drive, yikes how are we going to get to mars.

    The experiment with a loaded cart is the same you just added more mass, you surely cant be saying that two magnets are going to stop the craft taking off, the engine is the initial strong force it reaches equilibrium with the repelling magnetic field thus movement to the overall mass.
     
  14. Rocket Paul Registered Member

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    Guys if the magnets are troubling you change them for a spring and you get the same outcome, but remember a spring cannot push the engine right back to the bottom since the engine hat to travel to meet it..
     
  15. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    18,629
    It could be, but...

    There's nothing to admit: 1) If the "two craft" are connected magnetically then they may as well be connected mechanically. Ergo ONE "platform".
    (Unless your inability to explain extends to also being unable to explain what you mean by "two" - since it's obviously not the usual meaning).

    I don't agree on "two platforms". And if the rocket does move downwards then there's no overall movement of the vehicle (as previously noted).

    Learn how to read - I neither said nor implied that. What I'm saying that adding the magnets has NO EFFECT WHATSOEVER except for adding mass and complexity.

    Correct. That "same outcome being added mass, added complexity and no advantages whatsoever.

    What?
     
  16. Rocket Paul Registered Member

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    Since we can't agree on two platforms I guess its pointless saying any more because without a second platform you can't get any force applied to the top, and even after all my explanations on how this CAN be done, I think its you who talks utter rubbish.
     
  17. Sarkus Hippomonstrosesquippedalo phobe Valued Senior Member

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    7,454
    So let me picture this...

    With regard stability: imagine you are holding a ruler in between thumb and forefinger, loosely enough so that it can swing freely. If you hold it at the top then the weight of the ruler below means that the ruler settles in a stable manner vertically downward. If you hold the ruler at the bottom however, it is tricky to get the ruler to stay balanced upright, and it is unstable.
    Your view is that if you put the engine at the top of a rocket, apply thrust to the top, you have the first scenario (holding ruler at the top) whereas applying thrust to the bottom is like the unstable second scenario?

    If this is what you are thinking then you may want to check the wiki page on Pendulum rocket fallacy. It doesn't go into too many details, alas, but hopefully it starts to get you thinking in the right direction.

    The magnet system you want to add between the inner and outer structures just seems to be the equivalent of a gimbal, and would be no different to gimballing an engine located at the bottom.
     
  18. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    18,629
    Dear god...
    Even WITH the magnets the ONLY force that counts is that applied by the rocket engine.

    Yeah.... you ask for people who know science to give a critique: you ignore it. You ask for a "rocket scientist" to give a critique: you ignore that.
    You demonstrate a complete lack of understanding and rely on ignorance and obtuse wishful thinking. If you could harness that to power rockets then you might have something. Otherwise...
     
  19. Rocket Paul Registered Member

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    Force applied to the front force applied to the back, now hold the ruler at the top and the bottom...? is it stable now...
     
  20. Rocket Paul Registered Member

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    Looks like you will never get it you say two craft but refuse to say two platforms you are very good at dodging, two craft in space one craft has lost propulsion so the other craft pushes it with repelling magnets attached to each craft or if its easier a spring attached to each craft the one pushes the other much the same as I have explained with my concept, but what you refuse to get your head round is one craft is inside the other.
     
  21. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    18,629
    Did you bother to read the linked page?
    What's your reply?

    They are NOT separate craft. ALL of the propulsion drives "both" - together. The are not independent systems and - as has been pointed out - may as well be mechanically linked (e.g. simply made into one "complete" rocket).
    There is NO propulsion applied by the magnets except to transfer the rocket engine's thrust to the "upper part".
    Any "push" provided by the magnets (when the rocket engine is off) applies in BOTH directions to BOTH "parts" - one goes forwards and one goes backwards. Thus (as also, multiply, pointed out) there is no overall movement of the craft.
     
  22. Rocket Paul Registered Member

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    Yes I have read it but its nothing like what I am saying he has not got a free moving engine and a second platform, engine and fuel tank are fixed, tell me what you think about what I just said one rocket pushing the other rocket that lost its propulsion does it work or not, I think maybe you will dodge the question.
     
    Last edited: Oct 27, 2017
  23. Dywyddyr Penguinaciously duckalicious. Valued Senior Member

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    18,629
    That doesn't make a jot of difference. Nor do you have "two platforms" since the thing can only operate as a complete unit.

    Which part of "They are NOT separate craft. ALL of the propulsion drives "both" - together. The are not independent systems and - as has been pointed out - may as well be mechanically linked (e.g. simply made into one "complete" rocket).
    There is NO propulsion applied by the magnets except to transfer the rocket engine's thrust to the "upper part".
    Any "push" provided by the magnets (when the rocket engine is off) applies in BOTH directions to BOTH "parts" - one goes forwards and one goes backwards. Thus (as also, multiply, pointed out) there is no overall movement of the craft" did you not understand?

    Going back to an earlier post of yours (which I'd missed):
    This is false.
    1) There MUST be a reaction on the entire thing (otherwise it wouldn't move).
    2) The propulsive force is where the rocket engine exhausts - at the bottom. There is no "force to the top" (the magnet does provide "force to the top" but ONLY in exactly the same way that "force is applied to the top" in any ordinary rocket, i.e. it's part of the entire vehicle.
     

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