Something i have been thinking for a month.. (yoyo revolution related)


#1

hey dude , there is a new throw. Have you tried it ? Not yet, how does it play? More stable than xxx.(usually a yoyo come out not long before that) or fantastic feeling(about finish or shape) or great for speed with a so reasonable price.

I am bored with this. Because every time I try , I got disappointed. Nothing greatly has changed, still about 1 min effective spin time, still the H shape that like yoyorecreation, even worse people in my country became silver addicted… I am not rich since I am being a student, but if there is a throw really works, I would try my best to get it. So what is a revolutionary change for a yoyo? Like Tom Kuhn use ball bearing, Hspin made H-shape ,kind of this change really works.

You can’t define any yo that change as I mentioned before. You may say a clyw chief is amazing throw, but not epic, in fact it may be inferior to Sleipnir a throw originally made in 2008. Although we need to consider factor like price or appearance, but too many yoyos with no improvement…

Then how to make a revolutionary throw? I think the community is waiting for a great mechanist who gets yoyo addicted. A cad paper doesn’t work, you need real theory to get it right. I have heard that yyf is using a wind hole to test their prototype for right aerodynamics expression? That may be an active change. I am not a pro in mechanics, but I just want to show something after a lot of researching on it I have done.

Firstly is the bearing changing: a normal bearing is tightly sticked to the body of yoyo that will cause more friction, why not using a magnetic bearing, and we can put magnetic material in both of the yoyo body to make the bearing just in the right place.

Second is the axle changing: a normal axle’s screw thread may cause more friction ,why not move the axle’s center part screw thread? I don’t know exactly if the axle can works if applying this change…

Third is the shape: all the yoyo currently made reminds me of the alphabet “x”. so the “x” is just so great that people can not drop it ? I think it’s time to make shape like this! yeah a spintop like shape! So you may ask why this ? just be bored with “x”? not yet. I am trying to challenge the aerodynamics… which lead to a longer spinning time for horizontal throw!

Above is the shape i am chasing…

Below is a java applet from nasa’s free tutorial about aerodynamics which tell us something related to lift.

So it’s easy to see that a more angle degrees make more lift! So what happened when we throw horizontal skill ? it will tilt a bit like the picture showed below. Then you will see the top is more angular while the bottom is plain by this spintop like design which will make more lift. And we need this lift to make our baby glide for longer.

You may see the strange hole-like thing near the a-zone right? That’s another fantastic thinking! Imagining when we throw horizontal, the air behind the yoyo will be blow out in a short time, and there is a pressure difference . if we get some hole , will it achieve some kind of jet effect and give more lift? And for sure it will cut more contact area between string and yoyo which will reduce a lot of friction!

The last is something related to theory: what should be done for a more advance yoyo? I think we should consider the precession. Here is the definition of precession given by howstuffworks

if we can slow down the angular velocity of precession, it’s sure that we can have a longer spin time when doing horizontal tricks. You can easily understand how to get it from wikipedia:

So r is the key to it , reduce the radius will work. We can increase the weight in the middle area of yoyo. Some people may think, oh no , yoyo will spin shorter if the weight is centered. So the wide spin top like shape will help again to solve this problem!

P.S. :there may be some picture display problem you can go to my flicker to see the original pic.


#2

I don’t really understand your point about bearings. That they’re tight to the yoyo body is actually an effort to reduce friction. You want them tight as possible so no potential energy goes to waste between the bearing and the yoyo. The loss of energy from a bearing, besides heat from rolling resistance, is when the ball bearings are imperfectly round or imperfectly aligned and they “slip” inside the bearing while it turns. This could be improved upon with better machining tolerances, but this is probably cost prohibitive for a relatively low cost recreational activity.

Magnetic bearings would still be tight to the yoyo, but they use a magnetic field rather than ball bearings in order to separate the inner and outer tracks allowing them to turn. Unfortunately, pretty much all magnetic bearings are actually electromagnetic, and require an external power source, so they’re totally impractical for this application.

I also think your little cutouts near the response area would tear a string to bits. I suppose the edges could be rounded but I’m not sure what effect that might have on the aero.

Not that it isn’t nice to see someone thinking seriously outside the box. I guess I’m just wondering what kind of benefits we’re talking about. Is this shape 5% more efficient or 200%? And, could it be made in such a way, both shape and weight, that a human could still comfortably play it and perform all or most current tricks…or is it just a bid for spin time/stability?


#3

Short, straight answer: I’m afraid you’re wrong about just about everything. Putting weight near the axis of the yoyo makes it less useful for stability, no matter how close to or far from the center plane it is. Precession can already be more or less eliminated by using a string-centering bearing such as a KonKave. Aerodynamics is a negligible concern for yoyos, especially in terms of lift—don’t forget the shape is symmetrical, pulling down as equally as up. Adding holes won’t change anything important, unless you like whistling yoyos. Magnetic bearings are a dead end—clean metal bearings already reduce bearing friction to where you can practically ignore it for anything but long sleeper contests, the real friction comes from the string rubbing against the walls because of sloppiness in play. And yes, they should be “tightly sticked” to the yoyo for best performance. Threaded axles don’t increase friction on anything but the holding together of the yoyo, which is exactly how you want them to function. Finally, your yoyo has no response system and would thus lack the most important friction of all…the friction to get a powerful spin at the beginning of a throw and return to your hand at the end of one.


#4

Is that correct? What does the position of the string have to do with precession?
Isn’t precession a property of the spinning yoyo?

If that were true, then everyone would have concave bearings. Since most yo-yos do not; I surmise that the string position and or the bearing; is not the problem.


#5

There’s an old saying: “If it ain’t broke, don’t fix it.”

You may be bored with the yoyos you get, but I get freaking excited for every single throw I get. It doesn’t matter if some kid said that it ‘sucks’, I’ll make the most out of my yoyo and I’ll make it awesome.


#6

Necro…


#7

[quote=“YoyoGeezer,post:4,topic:36040”]
Try this experiment: Take a really wide-gapped yoyo and put a flat bearing in it. Give it a good throw. While it’s spinning, get the string to go to one edge of the bearing. Wait a bit. Take note of what happens. Then get the string to go to the other edge of the bearing. Wait a bit. Take note of what happens. Then put a KK or groove2 in. Throw it. Wait a bit. Take note of what happens.

For a more extreme but less direct example, throw a yoyo equipped with hubstacks, then (while it’s still level) lift it by one of the hubstacks, possibly using a pencil stuck in the side.

There are other ways to experiment with precession. Thumb grind a yoyo. Or put a weight ring in one side. Or put together two guts-compatible halves of yoyos, but with one of them larger or heavier than the other (people get all surprised that it doesn’t wobble when they do this…but wobble comes from other factors to begin with).

[quote=“YoyoGeezer,post:4,topic:36040”]
Well, precession usually doesn’t cause so much of a problem unless you’re doing 3A. And since most people don’t do 3A, or market their yoyos as 3A yoyos, flat bearings tend to do the job quite well.


#8

If we could some way incorporate “Lift” into horizontal play, I’d be fascinated…And if we can electrify a yoyo…I am so down for that.

Magnetics also seem like a really interesting/bad idea that I would love to see someone work on.

I don’t mind plugging my yoyo into the usb port to charge it!

I have also thought it would be interesting to have a yoyo that is somewhat hollow like a bell and then I could wrap up loops of strings around 5 of my fingers creating a harp. If I could then strum the 5 strings and create music or chords or at least tones with the yoyo…that would be ridiculous!


#9

Precession is the result of moment acting perpendicular to an angular momentum or a component of an angular momentum. The moment must have some sort of constrained center location (or pivot point) to act through in order to generate the the precessional rotation. On a yoyo there is only one such pivot location, the furthest point from the hand where the the string contacts the bearing/axle. If the yoyo is spinning perfectly smoothly and the string is perfectly centered, and the yoyo is perfectly balanced from side to side, there will be no precession. This, of course, is a very rare situation. On a well made yoyo with a good throw and a reasonably centered string the forces that cause the precessional rotation are generally quite small, and the resulting precession is very small to not noticeable.

db


#10

You know what might be a good name for a levitating horizontal yoyo? The UFO!


#11

Not trying to start an argument - I truly am ignorant about this angular momentum stuff.
Is it true that a perfectly balanced yoyo has no precession?

I thought that the two halves had to spin in opposite directions to cancel each other’s precession out. If each is spinning the same direction, won’t it mean 2x the precession?

Am I missing something?


#12

Exactly. I think the yoyo is fine how it is right now. It’s simple yet extraordinary. And it’s fun.