John Gs Wheel

[john_g]

Harvey

Ref your comments, I think you are correct, impact means loss of energy, however I think there is a trade off between requiring a quick action and total smoothness of movement, and the impact cound be used to add energy to say the rim. Your last paragraph holds the key but it may not be neccessay to store the energy in a spring.

Regards

John

As John G. states above, the wheel in Stealth's dwg is asymmetric.

This could be purposeful, or neglectful it is hard to say, but the result would be that some of the rollers simply cannot move inboard as far as others.

I use the term roller here, because we do not know that the rollers are spherical. In my drawing above, my rollers were long cylinders connected to two endpoint wheels as drawn. All you see is the end-view. This is the first place that I have shared that information. That element immediately changes the mass acceleration force in the F = ma equation where 'a' is the acceleration of 9.8m/sē. And as you may imagine, can overscale the frictional resistance of the system by several magnitudes.

Cloxxi's reference to the third or fourth derivative of position (where velocity is the first derivative and acceleration is the second) is an interesting thing to ponder. Even a small child understands the third derivative which we call 'jerk'. We see this sudden change in acceleration throughout our daily lives and we intuitively apply it to overcome the moment of inertia associated with stationary objects that just won't budge otherwise. Like a kid whose wagon wheel gets stuck behind a root sticking out of the ground, who first leans away with a pull, intuitively changing his leverage to no avail. Next he will roll the wagon back a bit and then steady pull it to see if that gets over the hump only to find it stops with that constant and steady velocity. So next, he rolls it back and then pulls faster and faster, accelerating all the way up to the point of impact only to find that it bounces back. And finally, without doing any calculus, he intuitively 'jerks' the handle just as the wheels are about to impact the root and that extra change in acceleration at the right moment does the trick and over the root it bounces.

Weight lifters use it to snap the weights at the right moment. Rockets use it to get the final escape velocity. Animals use it to catch their prey at the last moment.

So if there is a means to apply that third derivative, without losing energy do to impact (anytime you hear a sound from the transaction, you have lost energy) then I would say that it could be quite useful. Here is a secret: Compress a spring orthogonal to the rotation of the wheel using gravity, and then release it tangent to the rotation of the wheel and in connection with the wheel and you will have successfully converted the gravitational energy to kinetic energy by using two conservative forces. When done properly, energy can be extracted from the gravitational field.

[rickoff]

Rick, would a simple ramp South East not help the balance of the wheel assuming coutner clockwise rotation?

I'm not quite sure what you have in mind. Could you show a sketch with the ramp configuration? Would this be a replacement (alteration) to the current ramping, or an addition to it?

Rick

[Stealth]

Springs?

By adding a spring to a gravity wheel,would it not act as a dampening effect? resulting in loss of thrust on the outer rim.The rolling balls have a hammering impact on the rim. Any material on the inside rim that would not transfer energy to the rim would dampen the impact on the rim,causing a loss of energy.I have been trying a few ideas on this wheel, and have decided that the best material to be used in this configuaration is not a ball at all,but a liquid.It would have the ability to produce the hammering effect, and also,retreat and hammer again until it settles . You could possibly get 2 or 3 effects with a liquid. A heavy liquid like mercury would definetly have a strong impact force. Good Luck with your wheel. Stealth

[Harvey]

If the mount is rigid, then the spring will store the energy given to it.


Imagine we have a wheel with a weight at the 12 o'clock position and that a cam compresses the spring orthogonally and the spring is latched in the compressed position - let's say that the spring is vertical and we used the gravitational leverage of the falling weight to compress the spring. Note that this form of compression has zero effect on the wheel motion because a force applied perpendicular to the axis of rotation provides zero torque to the wheel. So it neither slows it down, nor does it speed it up. But, we have taken some measure of our gravitational force and applied it to compressing the spring during the downward motion of our weight. So the overall acceleration of the wheel will be less than if we did not compress the spring.

Now suppose that after compressing the spring we allow the weight to continue onward, like a pendulum and it swings perhaps only up to the 10:00 o'clock position. Gravity supplies a negative acceleration during this time and that slows the wheel to a stop. We do not get 360° because of the friction in the system and because we have transferred some of the energy to our spring. While this is happening, a mechanism with some losses in it, moves the spring into a tangent position and the latch is released bringing the weight just short of 12 O'clock because of the losses in the system.

We have shown then, that energy can be taken from gravity and stored in a spring to later be applied to the kinetic acceleration of the wheel. But this was not a wise use of the spring's stored energy because we used it to accelerate the wheel from a stopped position. Now, what if we instead, allow the weight to swing back like a pendulum and just as it passes bottom dead center we release the energy in the spring to accelerate the wheel further? Will the momentum of the system, and the application of the 3rd derivative have a different effect? Will the weight go past the TDC mark?

Interesting to contemplate.

[john_g]

If the mount is rigid, then the spring will store the energy given to it.


Imagine we have a wheel with a weight at the 12 o'clock position and that a cam compresses the spring orthogonally and the spring is latched in the compressed position - let's say that the spring is vertical and we used the gravitational leverage of the falling weight to compress the spring. Note that this form of compression has zero effect on the wheel motion because a force applied perpendicular to the axis of rotation provides zero torque to the wheel. So it neither slows it down, nor does it speed it up. But, we have taken some measure of our gravitational force and applied it to compressing the spring during the downward motion of our weight. So the overall acceleration of the wheel will be less than if we did not compress the spring.


Now suppose that after compressing the spring we allow the weight to continue onward, like a pendulum and it swings perhaps only up to the 10:00 o'clock position. Gravity supplies a negative acceleration during this time and that slows the wheel to a stop. We do not get 360° because of the friction in the system and because we have transferred some of the energy to our spring. While this is happening, a mechanism with some losses in it, moves the spring into a tangent position and the latch is released bringing the weight just short of 12 O'clock because of the losses in the system.

We have shown then, that energy can be taken from gravity and stored in a spring to later be applied to the kinetic acceleration of the wheel. But this was not a wise use of the spring's stored energy because we used it to accelerate the wheel from a stopped position. Now, what if we instead, allow the weight to swing back like a pendulum and just as it passes bottom dead center we release the energy in the spring to accelerate the wheel further? Will the momentum of the system, and the application of the 3rd derivative have a different effect? Will the weight go past the TDC mark?

Interesting to contemplate.

Harvey

Talking about springs, one thing that I find interesting is the reaction you can get with a self retracting tape measure. Hold tape measure lightly between say thumb and finger so the tape can rotate about the reel axis. Pull out the tape say 12 " then release it. The turning reaction is very marked and strong (depending on tape type) for what appears to be little input.

Regards

John

[Cloxxki]

I'm not quite sure what you have in mind. Could you show a sketch with the ramp configuration? Would this be a replacement (alteration) to the current ramping, or an addition to it?

Rick

Rick,
Really, I suppose I am pretty much proposing the way the forums understand the workings of the "Abeling wheel".
I'm pressed for time right now, but imagine the rollers sticking out from the side of the wheel. In the south east corner, ramps that sit alongside the wheel, prevent the rollers from finding the rims, resulting in a tight path upward. No outer position, no counter torque when turning counter clockwise.

Some say that the positions weights take on the Abeling wheel, mathematically prove it to be OU. Mass out of center, torque over balanced in each phase of rotation, that should bring a spinner. I am not believing it just yet, as I've never seen a seesaw setup where one weight managed to lift the other. They balance. And if they don't balance, the upward weight never get as high as the downward one dropped for it.

1kg on a mile long lever is still not going to lift another 1kg weight (1 foot lever opposite the seesaw pivot) up higher than the work done by the weight on the long end of the lever. Even working as a spring board, the spring will release too slowly to catapult the weight up higher than the other one came from.

With such a winded reply I have a bad case for being pressed for time. If I was unclear, I'll sketch you something or refer some Abeling replication video's, especially by Youtube poster batgold.

[Harvey]

Springs, Levers and Magnets - oh my . . .

John G,

In my younger years I was a fairly proficient drywall hanger and my tape was the lifeblood of my work. So I am quite familiar with the force delivered from a retracting blade. Not only can they cut pretty good if your too close to edge, but they can deliver a fairly painful blood blister if you happen to leave a digit near the opening when that metal tip arrives home. The springs in those tools are every bit as long as the tape itself and are wound tight as a clock-spring when the blade is fully extended. That noise you hear when you pull it all the way out is the friction of the spring rubbing on itself as it reaches full compactness. That is usually when the center spindle snaps off or the end point of the spring where it flexes most simply gives up and breaks. I've rescued more tapes than I can remember by cutting new notches in the end of the spring after they broke, but then I'd have to wind one or two wraps of the blade inside to make up for the lost section. Clocks and watches have put that force to work for centuries. But the specific impact that you refer to has its origin in the mass acceleration involved. Internally, not only is the mass of the blade in motion, but also the spring itself. And as the blade rewinds, it keeps adding to the angular momentum of the internal wheel increasing its diameter. The spring decreases in force (it is unwinding on retraction), and the wheel increases in velocity so when the tip reaches the case it has all that internal momentum pulling on it. The impact is tangential, so it is easily converted to kinetic energy in the case itself. But, don't underestimate how strong our muscles really are as to the energy stored in an extended tape measure. Put the end of one on a fish scale and measure the force, then weigh the tape to get an idea of how much mass that force is accelerating. F = ma, a = F / m.

@Cloxxi,

I agree that a balanced beam will not let one side be higher than the other if the lengths to the fulcrum are the same. There must be an outside force applied if a gain is to be had. You have probably seen the modern day Stonehenge being built by one man. He lifts thousands of pounds of concrete by himself using just a few buckets of rocks that he moves from one side to the other to alter the balance. He then moves the fulcrum height, increasing it on every swing by having two fulcrums side by side that alternate in supporting the weight while the other one is raised up to touch the inclined concrete block.

But it does make one think a bit . . .

Full Size

I posted this in another thread here somewhere, so you may have seen it before. It raises the question as to how much force a large moving mass has, and since it takes very little to make this be off balance (Like Peters Penny on the Wheel) we must ask ourselves if that acceleration can be converted to a usable form. If the bearing was nearly frictionless, how much force would that impact have?

I am also curious what you thought of the M.A.P. video I linked to in my other post above Post 93726

Cheers,

[Cloxxki]

@Harvey,
I'll need to look up that video when I get home.

On the mouse and weighted seesaw. I think the force of impact will be the equivalent of the mouse (20g?) falling the height from the end position of his bed, relatively to the food.
If the mouse actually takes careful little mouse steps to get to the food, the impact will be infinitely small. A part of the mouse's weight (it doesn't even move to the edge of the lever) will gradually be transferred to the granite.
I'll gladly place my finger right under the heavy load, to neatly keep the granite dust off it. Less scary than letting an actual mouse sit on my actual finger.

Fascinating to hear that indeed a heavy weight on a pendulum, being pushed laterally can see it be lifted each half cycle. Not surprising though, as swing with a fixed pivot equals height gain. When one quickly adjusts the cord which supports the weight at the highest point in the swing, it will not swing back down. Only lateral pushes are again required to set up for a height gain.
Makes me think for the 2-stage oscillator. Minute inputs evenly get a larger object to swing vertically. Ram a pillar in place under it just at the highest point, and the weight will stay up there. the energy to lift the weights is still required to be put in. Like one man's tax payment don't build a country, but if we all pay, we get nice roads and city halls.

[john_g]

John G,

In my younger years I was a fairly proficient drywall hanger and my tape was the lifeblood of my work. So I am quite familiar with the force delivered from a retracting blade. Not only can they cut pretty good if your too close to edge, but they can deliver a fairly painful blood blister if you happen to leave a digit near the opening when that metal tip arrives home. The springs in those tools are every bit as long as the tape itself and are wound tight as a clock-spring when the blade is fully extended. That noise you hear when you pull it all the way out is the friction of the spring rubbing on itself as it reaches full compactness. That is usually when the center spindle snaps off or the end point of the spring where it flexes most simply gives up and breaks. I've rescued more tapes than I can remember by cutting new notches in the end of the spring after they broke, but then I'd have to wind one or two wraps of the blade inside to make up for the lost section. Clocks and watches have put that force to work for centuries. But the specific impact that you refer to has its origin in the mass acceleration involved. Internally, not only is the mass of the blade in motion, but also the spring itself. And as the blade rewinds, it keeps adding to the angular momentum of the internal wheel increasing its diameter. The spring decreases in force (it is unwinding on retraction), and the wheel increases in velocity so when the tip reaches the case it has all that internal momentum pulling on it. The impact is tangential, so it is easily converted to kinetic energy in the case itself. But, don't underestimate how strong our muscles really are as to the energy stored in an extended tape measure. Put the end of one on a fish scale and measure the force, then weigh the tape to get an idea of how much mass that force is accelerating. F = ma, a = F / m.

Harvey

I applicate what you correctly say,however it strikes me rightly or wrongly, that the laws of conservation of energy, when applied to a rotating, spirally retracting object seems to produce a strong effect which may warrant further investigation - I cannot find any info about it.

John

[Harvey]

@Harvey,
I'll need to look up that video when I get home.

On the mouse and weighted seesaw. I think the force of impact will be the equivalent of the mouse (20g?) falling the height from the end position of his bed, relatively to the food.
If the mouse actually takes careful little mouse steps to get to the food, the impact will be infinitely small. A part of the mouse's weight (it doesn't even move to the edge of the lever) will gradually be transferred to the granite.
I'll gladly place my finger right under the heavy load, to neatly keep the granite dust off it. Less scary than letting an actual mouse sit on my actual finger.

Fascinating to hear that indeed a heavy weight on a pendulum, being pushed laterally can see it be lifted each half cycle. Not surprising though, as swing with a fixed pivot equals height gain. When one quickly adjusts the cord which supports the weight at the highest point in the swing, it will not swing back down. Only lateral pushes are again required to set up for a height gain.
Makes me think for the 2-stage oscillator. Minute inputs evenly get a larger object to swing vertically. Ram a pillar in place under it just at the highest point, and the weight will stay up there. the energy to lift the weights is still required to be put in. Like one man's tax payment don't build a country, but if we all pay, we get nice roads and city halls.

So how fast does the mouse eventually go?

I would imagine, that given enough time, the Moment of Inertia will be fully overcome by the force of the mouse being pulled down. And that the force will continue to accelerate the entire system to an 9.8m / sē, and this results in a very large mass gaining momentum over that long period of time at which point the full inertial force will be felt by the granite.

But I may be wrong - how could we solve this mathematically? Perhaps angular velocity is involved and force vectors change

[Cloxxki]

So how fast does the mouse eventually go?

I would imagine, that given enough time, the Moment of Inertia will be fully overcome by the force of the mouse being pulled down. And that the force will continue to accelerate the entire system to an 9.8m / sē, and this results in a very large mass gaining momentum over that long period of time at which point the full inertial force will be felt by the granite.

But I may be wrong - how could we solve this mathematically? Perhaps angular velocity is involved and force vectors change

My gut feeling says the heavey balanced weights act as a damper on the mouse's descent. 0.2N of imbalance just doesn't throw 900kg up on one side, even if on the other is an identical 900kg doing its best.
The effect I expect would be similar to a mouse jumping off the canyon rim, with a very long rope around it's waist connected to two inline and level placed cute 900kg city cars. And in the drawing, the mouse doesn't even transfer the full length of the beam, which reduced the effect.
At first, the mouse will seem to hang still from the rope, and then ever so slowly start to descend. Like watching paint dry. Even after 80m worth of calender-wasting descend, the KE in the cars will not be greater than the potential energy of a 20g mouse on an 80m canyon wall.
If your principle proves to offer gain, I'll dedicate serious time to assist you in making a device out of it!

[Harvey]

Harvey

I applicate what you correctly say,however it strikes me rightly or wrongly, that the laws of conservation of energy, when applied to a rotating, spirally retracting object seems to produce a strong effect which may warrant further investigation - I cannot find any info about it.

John

Hi John,

You may be on to something with regards to the concentration of energy. Baseball players intuitively use spiral energy both in pitching and in hitting to concentrate the energy to a single point. Ballet dancers and skaters demonstrate the Conservation of angular momentum when they spin in place and accelerate by pulling their arms in. Perhaps the concept lends itself to a means of energy conversion and storage that reduces losses.

It would be interesting to see what you find out about it.

[Cloxxki]

Hi John,

You may be on to something with regards to the concentration of energy. Baseball players intuitively use spiral energy both in pitching and in hitting to concentrate the energy to a single point. Ballet dancers and skaters demonstrate the Conservation of angular momentum when they spin in place and accelerate by pulling their arms in. Perhaps the concept lends itself to a means of energy conversion and storage that reduces losses.

It would be interesting to see what you find out about it.

Easy idea. Spin over 3 axes. Stores lots of energy, at low rpm.

A spherical weight spins in horizontal plane 1000rpm, sitting centrally on a vertical rod. Stored KE : 1.
Now, device a enclosement that allows you to maintain this horizontal (x axis?) 1000rpm spin, and start inputting Y axis spin, again up to 1000rpm. And again, for Z. Logic suggests to me that 3x the KE energy would be stored. This might actually prove to be incorrect, due to a shorter distance being travelled than when spinning up to 3000rpm. THEN however, 1/2 M*Vē would apply, and KE would be 9.

One thing I know, being spun over 3 axes at the same time can really upset the stomach. And, everyone faintly interested in such concepts, should own a Powerball. You can FEEL the 3-axis gyro power, and input more into it by finding the path of most resistance.

[john_g]

Hi All

Quick update on my wheel progress. Made up some new brackets today to go onto the support stand and mounted proper bed bearing onto them. Also increased the width of support stand so the wheel is central rather than hanging off the stand. I noticed running the shaft through the wooden cutouts as the weight of the wheel was increasing so was the friction - which you would expect but it was a lot more than I had anticipated.

Regards

John

[Harvey]

Hi All

Quick update on my wheel progress. Made up some new brackets today to go onto the support stand and mounted proper bed bearing onto them. Also increased the width of support stand so the wheel is central rather than hanging off the stand. I noticed running the shaft through the wooden cutouts as the weight of the wheel was increasing so was the friction - which you would expect but it was a lot more than I had anticipated.

Regards

John

Hi John,

Just a few links associated with the increased negative torque you are experiencing:

SKF Evolution Online > Measurement & quality-assurance > Research & Theory > Other > Other > Using a friction model as an engineering tool

Rolling Bearing Friction

Rolling resistance - Wikipedia, the free encyclopedia

One thing that is very counter intuitive, is that the coefficient of friction does not increase with surface area. So larger bearings do not change the CoF. This is somewhat difficult to imagine. A physics professor at MIT would use sandpaper and tires as examples with an incline plane, proving that larger contact surfaces did not change the breaking point (holding power of the friction against the force of gravity in those demonstrations). The breaking point is dependent on the materials in contact and the pressure applied.

What about Passive Magnetic Bearings?

Passive Magnetic Bearing Development

Cheers!