Posted by Scott Ellis (216.87.95.64) on January 03, 2003 at 20:03:19:
In Reply to: Besslerwheel vs. centrifugal/centripetal forces... posted by Øystein Rustad on January 03, 2003 at 17:05:38:
Hi Øystein,
Thanks a lot for your post. I would like to follow up by posting the relevant discussion we had recently about this topic. Hopefully it will help catch people up on the ideas and illicit some responses...
Thanks, Øystein, for your permission to post this material.
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excerpt from an email from Øystein - 12/28/2002
Hello !
After reading your comment on how we can get unbalance from a wheel that is balanced when not in motion or moving slow. I thought through a couple of solutions, I have attached 2 of them, please read then with an open mind, and let me know...I am not all fired up from this, but I think specially the first is an int. view, and should be looked at !?
I just spent about 30 min. thinking this through so don`t take my word for it :-)
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excerpt from an email from Øystein - 1/1/2003
I have now done a more thorough description of my "double centrifugal pendulum principle".
Now you maybe will understand what I mean :-)
I can`t see why this at least theoreticall is a Gravity harnessing principle !
Please give me a feedback on this, will you ?
I think that maybe more brains could make this principle more effective, put in a better "system"...
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excerpt from a response email from Scott - 1/2/2003
Thanks a lot for this followup email. Indeed, I did not respond to your last email yet because I was still trying to understand it. I think I see better what you are saying now. It is definitely an interesting idea! I think it might be hard to predict the exact effects though... Do you think you can prototype it?As you mention, the mass's swing radius gets larger as it swings downward (when the spring is being compressed). One thing to keep in mind here is the Conservation of Angular Momentum (as generally accepted, but Hans Wiedenbusch would disagree... ;-). First imagine there were no gravity (say the apparatus were spinning on a horizontal plane). If the swing (or spin) radius increases, then the speed of the weight must decrease, right? This might offset the gravitational effect you predict?
?Another thing I thought about was that this seemed to actually be the OPPOSITE of pumping a swinging, as far as I understand it. To pump a swing, you must LIFT the mass at the bottom of the swing. (In this scheme, the weight is LOWERED a the bottom of the swing). In conventional analysis, the spring here is doing negative work (in the same direction as gravity). And as far as I can tell, lowering the weight at the bottom of a the swing doesn't pump it, but instead slows it down.
??BUT... I think the idea is interesting and might be hard to predict. I don't really get the concept of "negative work" anyway, since it seems based on a poor understanding of gravity to begin with as a "conservative force." The concept of "negative work" was introduced just to make the conservation laws work out properly in mathematical equations. And as you know, Inertia is one of the least understood principles in nature and is intimately related with gravity (e.g. Mach's Principle). Isn't Inertia what's really going on with Angular Momentum and the phantom "Centrifugal Force?" We are taught that centrifugal force is an illusion, and that the only real force is centripetal. Experience says otherwise... maybe Hans is onto something!
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excerpt from an email from Øystein - 1/1/2003
1. Yes, it could be posted on the board, even if it is a veeery crude drawing...
2. Yes, conservation of angular momentum still holds.
3. Gravity (mah) is bigger when falling.
3. Energy added to the rotation is always weight*arm*distance, (in every spring bases mechanism), you can of course
calculate this by calculating torque * distance, the energy transfered to the spring, is the same energy tha one that feels centripetal force) as a tiny person excerting force on the spring,
We can se that angular momentum is still true, but the weight * arm has always been bigger, and so do the total (mgh).
9. I think that the whole concept of imaginary forces, and centripetal forces etc, are bull and crap, and just wording to confuse us !
A real force is a force that will make a distance change if not the opposite and equal force is excerted in the opposite direction, FACT !
I may be able to get this buildt, by another mechanican, but friction etc, would be very critical, but I believe I have found a way to use this in a wheel.
If we can make the attachement of a weight and spring have "ahead" (at the top erea) and "catch up" periods (at bottom) through the revolution, the centrifugal force will
be lost at the bottom and a weight can be lifted on the now motionless system at the bottom ! (directly remove centrifugal forces from the lift, and adding centrifugal force to the fall)
THIS IS TRUE : Because work to lift a mass MUST BE : total force (gravity + centrifugal/centripetal +/- spring) * distance !!!
Here's hoping this produces some discussion,
Scott
: Hello again :-)
: For the ones int. I thought I should "bable" a bit about how besslers wheel was related to centrifugal forces mathematically !
: In his biggest wheel we can calculate how big the centrifugal forces wore, and from that see if they somehow could be a major factor, an maybe we can find a "lucky" relation !
: Lets see at what RPM the centrifugal forces will be equal to gravity !
: RPM(Fg = Fc) = (g * r)^1/2 * (60 / pi*2r)
: g = 9,8
: r = 1,825
: Resault = 22,1 RPM !
: At this RPM the weights are "weightless" at the top and
: have F = 2g at the bottom.
: We know this wheel rotated at about 24 RPM unloaded and about 20 RPM loaded.
: :-)
