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Reaction torque propulsion

  1. Mar 31, 2004 #1
    What do you think of this web page? Reaction torque propulsion
    It challenges some important notions.
     
  2. jcsd
  3. Mar 31, 2004 #2

    NateTG

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    It ignores the that the axle exerts a force or assumes an incorrect center of rotation.
     
  4. Mar 31, 2004 #3
    It would work regardless whether there a force on the axle or not. Please refer to the home page : http://www.spacecrab.com/ where there is an link to the demonstration and to the concept of the center of rotation!
     
  5. Mar 31, 2004 #4

    NateTG

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    Ah. Right - my bad. The problem is that 'propulsion' is a misnomer. Things like this can be used to change orientation only.
     
  6. Mar 31, 2004 #5
    If you click on the Proof link, there is another link to Translation showing that this concept is used to propel a hovercraft. Previously reaction wheels were only used to maintain a satellite's attitude, now they can be used to propel a spacecraft.
     
    Last edited: Mar 31, 2004
  7. Mar 31, 2004 #6

    NateTG

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    None of the rotations move the center of mass. Propulsion as you describe it is not feasible. I will not post on this thread again.
     
  8. Mar 31, 2004 #7
    It is a question of facts and logic. Physics is the explanation of facts and logic!
     
  9. Apr 2, 2004 #8
    Ray, with all due respect, I have researched this subject guite thoroughly, and have been interested in it for some time.
    My observations and experiments(basic) have indicated that unidirectional thrust phenomema does indeed exists. That's not the problem. It is EASILY demonstrated in many "one-shot" schemes. The problem is making it occur again and again for continual thrust.
    Curiously enough, Ray, as you may know, if the general premise is that "energy is expended", no violations occur.
    In my own endeavors, "vector translation" is key. That is, a given force vector alters it's orientation with respect to origin.
    Now, a part of that aspect is readily seen in gyroscopic mechanisms, yet the vector shifting is merely displaced in the same axis orientation, though in a different lateral place. Interesting, but not at all useful for unidirectional thrust.
    Several years ago I designed a very simple mechanism which causes a forward or upward motion in excess of resultant downward motion.
    Nobel prize? World changing invention? No.
    It works, but only works on the first input pulse. Nothing is violated in physics because energy is expended in the process. I have never been able to effectively cycle the event. So, it remains as a one-shot "reactionless" shock absorber until I can further develop the device.
    Having not much luck in traditional force translation sciences, I am encouraged in the unusual aspects of shock wave propagation, specifically non-linear spherical. How this might go with my own designs remains to be seen, though I would encourage you looking into it.
     
  10. Apr 2, 2004 #9
    This isn't a one shot deal. Please refer to:
    http://www.spacecrab.com/Proof.htm
    the Translational Motion link proves that the hovercraft moves continuously using reaction torque. The rotational vectors are combined to produce a translational motion.
     
  11. Apr 3, 2004 #10
    Ray, having viewed your video and read your site many times today, I suppose I might see why you have the impressions you do.
    However, I considered if the effect shown might be a result of "friction-walking", where differing moments of inertia against contact friction causes the effect(consider the worm or snake). I know that the device is a hovercraft, but it by no means suggests that surface friction is zero!
    So, to resolve this I considered what whould happen if the same device shown in the video was not on a table, but rather suspended in some special way to eliminate friction-walking as a possible cause.
    I would suppose that you have also considered special variations on the experiment to exclude such factors. I would also suppose that you see such variational endeavors to be absolutely paramount in establishing claim credibility, and that you would aggressively persue such matters.
    What I am saying, Ray, is this: the video is NOT a truly convincing "proof" of your claim.
    Why? Because a trained eye see's walking friction regardless of any contention from you to the contrary because walking friction is DEFINITELY a component in your demonstration as designed.
    Now, this does not mean that the effect you present is not real or worthy of further inquiry, it simply means that your experiment as shown DOES NOT exclude enough aggrivating factors to be convincing.
    So, it is incumbent upon you to address these concerns, and to design an experiment which is much more acceptable. Are you willing to do that?
    Does not the true researcher or experimentalist or inventor critique their own designs with breathtaking brutality until an outstanding, peer-reviewable product is achieved?
    So, let us now examine your idea and seek to improve its purest experimental expression worthy of the most discerned critique. Agreed?
     
  12. Apr 3, 2004 #11
    That is a very intelligent and constructive idea. The Demonstration link on the home page at http://www.spacecrab.com/images/DoubleRotation.mpg proves to me without any doubt that there are two rotations as predicted by the physics from the Physics link. All told it is very convincing to me, but I'm willing to try any experiment. The ideal of course would be to test it in space!
    The problem is what do I do? I have considered drop towers, air tables, pendulum test, elliptical flight (vomit comet) and they all have their advantages and disadvantages. I even tried to obtain some near-frictionless coating from http://www.techtransfer.anl.gov/techtour/nfc.html I was convinced the hovercraft test was the best, though I can appreciate the "friction-walking" criticism.
    I am open to any concrete suggestion. Please send me an E-mail.
     
  13. Apr 4, 2004 #12
    Upon reflection I find the objection based on "friction walking" rather farfetched. The hovercraft does have a rocking behavior but saying that this compresses air within the plenum, that has no baffle and is open on its sides, is exagerated. Even if there were some friction, nothing acts on it, certainly not the rotating balsa wood loads!

    I have tried to get help from many engineers and from the academic community and except for the very few they dismiss my invention offhandedly without proper scrutiny. Perhaps their cynicism has overcome their curiosity!

    I remain open to suggestions and full inspection. I await concrete and constructive comments.
     
  14. Apr 4, 2004 #13
    Excellent! Ray, I am VERY impressed by your both your hands-on nature to develop a theory and, most importantly, your willingness to consider more detailed examination and special experimentation(s) into this theory.
    Agreed, the "friction-walking" may or may not be an integral factor in the effect, so I should retract my original statement defining it as an absolute. However, it certainly must be eliminated from all possible influence, and I can see that you do indeed desire the same. Good job!!
    As soon as I get off work I will get on to it.
     
  15. Apr 5, 2004 #14
    I am aware that all possibilites have to be investigated. There could be a jerking behavior produced in other inventions that use the difference between static and kinetic friction. I don't know how to eliminate these possibilities and that is why I'm using this forum.
    I'm looking forward to your contribution, pallidin.
     
  16. Apr 5, 2004 #15
  17. Apr 5, 2004 #16
    To palidin,
    Our discussion has led me to devise a simple variation to test whether friction has any effect. All that is needed is to change the surface under the hovercraft so that there are various coefficients of friction; if friction has ANY kind of effect, we should expect the hovercraft to move at different velocities. Of course the hovercraft has to be sturdy enough to produce constant results; the toy model I used should be upgraded.

    By the way, the tests I made were done on highly polished travertine that should have a very low friction coefficient.
     
  18. Apr 5, 2004 #17

    enigma

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    The other option of course is aerodynamic forces. You have two giant (relative to the body) propellors on the thing. Even if you've lined them up perfectly perpendicular, the motion about the CG due to the rotations may cause non-zero angles of attack as the craft crawls forward.
     
  19. Apr 5, 2004 #18
    Enigma brings up a valid observation.
    A suggestion, Ray: That particular aspect is easily addressed in re-design by completely enclosing the spinning elements so that no external aerodynamic forces are potentialized. Since both extension arms are static there are any number of ways to do this, from individual plastic spheres to entirely exclosing part or all of the apparatus. For that matter, a million thoughts on how to achieve isolation from aerodynamic influence is now crossing my mind. I would choose whatever least expensive option for now, as any option should be equally effective.

    Your suggested variation which incorporates varying surface coefficients is interesting.

    I also looked at your link with regards to compensating for friction, but at this point, my opinion is that it is not necessary and actually might complicate matters.

    Just throwing thoughts out now:
    First of all, I consider the effect worthy of further study, because the device uses and expends energy, also, that the "effect" is less than the energy used to create it. This tells me that the device is not asking "something for nothing"
    Of course, this doesn't mean that the effect is separate from normal causes or holds any special promise, it means that the effect should be investigated, in my opinion.
    Ray, I have closely examined the concept behind the extension arms with the motors and off-centered balsa wood, and apart from the possible aerodynamic effects noted by Enigma, I have also noted another prevalent set of dynamics going-on: very rapid cyclic compression and extension forces placed on the support arms(frequency roughly equivalent to the motor armature)
    When the balsa wood is rotating away from the support arm the support arm experiences an extension, however slight. When the balsa wood is rotating towards the support arm, the support arm compresses. In fact, the effect is not linear, and so the support arm will also slightly bend left and right as well as in and out during this off-centered rotation of the balsa wood.
    In addition to the above dynamics, and as noted in your web site, a constant torque tension is being placed on each arm, due to the fact that the end of the arms support the motor housings, which produce opposite rotational torque with respect to the motor armature and vectored on the center of system mass.
    On top of all this, the center of system mass dynamically alters by virtue of the rotating balsa wood, and this alteration is non-linear. That interests me.

    Ray, in summary, I would propose pursuing complete isolation of aerodynamic influence as presented by Enigma. That seems a healthy first design variation.
    If the effect continues to occur afterwards, then we can address the more problematic issue of designing a test which eliminates friction-walking as a potential.
     
  20. Apr 6, 2004 #19
    Thanks to enigma and pallidin, this is a very constructive discussion.

    The possibility that there is any propulsion by expulsion (of air) is remote since I did't feel much air displacement; of course outsiders aren't aware of this! However for scientific purposes I recognize that this possibility has to be excluded. In fact I had tested it by enclosing the mechanisms in cardboard, but they were too heavy. Furthermore this would not have been a very good demonstration, since the mechanisms would have been hidden. At any rate I concur that this test has to be done.

    From the getgo I was aware of the wobbly motion of the apparatus and I had a hard time explaining the behavior because of it. The ideal experiment would be to have authentic reaction wheels, but one manufacturer told me that they cost $50,000 each. Another didn't even quote a price. I had to forego this avenue because I lack the money to do this.

    As you know to produce a torque, which is a force, I have to have an acceleration. Simply rotating a load will not do the job. In order to simulate this, the loads have to be eccentric, however theey would cause wobbly motions that are problematic. If you observe the DoubleRotation.mpg on the Home page, you will see that the load was a disk originally but that didn't work because it quickly reached a constant velocity. I simply added some electrical tape to create a constant acceleration. I intend to do some more rigourous testing in the near future.


    I appreciate your comments very much.
     
  21. Apr 6, 2004 #20
    Thanks to enigma and pallidin, this is a very constructive discussion.

    The possibility that there is any propulsion by expulsion (of air) is remote since I did't feel much air displacement; of course outsiders aren't aware of this! However for scientific purposes I recognize that this possibility has to be excluded. In fact I had tested it by enclosing the mechanisms in cardboard, but they were too heavy. Furthermore this would not have been a very good demonstration, since the mechanisms would have been hidden. At any rate I concur that this test has to be done.

    From the getgo I was aware of the wobbly motion of the apparatus and I had a hard time explaining the behavior because of it. The ideal experiment would be to have authentic reaction wheels, but one manufacturer told me that they cost $50,000 each. Another didn't even quote a price. I had to forego this avenue because I lack the money to do this.

    As you know to produce a torque, which is a force, I have to have an acceleration. Simply rotating a load will not do the job. In order to simulate this, the loads have to be eccentric, however they would cause wobbly motions that are problematic. If you observe the DoubleRotation.mpg on the Home page, you will see that the load was a disk originally but that didn't work because it quickly reached a constant velocity. I simply added some electrical tape to create a constant acceleration. I intend to do some more rigourous testing in the near future.

    I appreciate your comments very much.
     
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