The physics of floaty?


#1

Is it possible to predict the speed at which a yoyo will play? The cliff is really floaty but it also specs that it should be heavier. I don’t get it. The chief isn’t that floaty but a lot lighter. Is there a diameter to weight ratio that suggests how it will behave?


#2

I am no expert, but here is my take on float.

Larger diameter, Less weight, Weight is more center focused than rim focused. My floatiest throw is my MFD Gelada, that thing just hovers.


#3

center weight= floaty, rim weight= solid


#4

But there is a lot rim weight on the Cliff (judging from the shape), also i don’t see center weight much since there is no center hub


#5

It is the positioning of rim weight near the undercut that makes it floaty.


#6

Oh yay! I’ve been waiting for one of these threads, and have been surprised to have not seen one earlier.

My take is that “floaty” is part physics and part “it’s all in your head”. In terms of physics, I think people underestimate the… er… zippiness at which a yoyo goes from hand to to end of the string (“unrolling?”). This is a function of the bearing, string, response, walls, and diameter of the yoyo, all contributing to whether a yoyo gets to the end of the string with a “thunk” or elegantly reaches the end of the string with a powerful spin and little or no “thunk”.

Since that’s the first sensation at the beginning of any trick, it’s going to inform your feelings. A C3 Token which has a heavy “thunk” at the end of the string, is never going to be called “floaty” even though it might have the same weight as another yoyo.

The H5xChief, on the other hand, spins its way out to the end of the string without a “thunk”, so it just feels elegant and “light for its size”. Well, it’s not any lighter. It felt lighter because it did not accelerate to the end of the string at the same velocity as a rock on a string. It “floated” to the end.


The second part is stability. Get a yoyo that likes to go off axis and which you have to micro-manage in terms of control, and it’s probably not as likely to be called “floaty”. It might get called “nimble” or “precise” but not “floaty”.

But you get a yoyo with spin dynamics that cause it to stay on-axis, and you can easily predict its motion through the air and the amount of control (or lack thereof) that you will need as it comes into a mount. Hate to break it to some of y’all, but if you hop it up, it’s going to travel the same arc as any other yoyo of the same weight. It’s not floating or getting any more hang time. At all. But because it’s so stable it reduces effort required to manage its trajectory.

Less effort likely results in a “floaty” feeling.


That’s my take on it. I don’t think that “floaty” is a total load of hooey, though I think that some people crank up the BS when they talk about movement through the air. I think there is some physics behind it. But the physics are NOT the yoyo as it flies through the air. The physics relate to the initial throw and the stability, as far as I can tell. These contribute to an overall feeling of effortlessness and casual ease which trick the brain into seeing the entire experience as one of “floating” the yoyo around your tricks and combos.


#7

Excellent explanation GregP! I especially like how you accurately described the physics of hops for yo-yos of the same weight and yet did not ignore the “in your head” feelings, which are not negligible. If everyone read this, it would clear up a lot of misconceptions on “floaty”! I find it a confusing word to use.

I think many of your principles also apply to the attribute of “speed”. It’s really about the weight of the yo-yo and the force it takes to change directions, but then the feel of the stability really gets into your head. However, the initial throw may be even more important for the feeling of “speed”, since the unrolling of the yo-yo can be truly “fast” or “slow”.

Thanks for the awesome post!


#8

Good. …and this can help explain why using a KK can make a yoyo feel “heavier”… it’s because a KK increases the “thunk” at the end of a throw.

As far as rim weight vs. center weight, and how more center weight being more floaty… I think there is truth to that. Think of the Protostar vs. Northstar… Protostar is actually lighter but feels more solid due to more rim weight, Northstar is floatier even though it is heavier due to gaining more center weight.

Also, I have 2 Peaks that weigh the same but the weight is distributed differently. More rim weight = solid, less rim weight (more center) = floaty.

EDIT: So I do think there is something to floaty that is more than just stability… but more on that later… This would be easier to think about by busting out some basic physics equations and considering the yoyo as a non-spinning object.


#9

The rim vs. center weight informs the spin dynamics, which will inform the manner at which the yoyo gets to the end of the string. And also the stability. So there’s still that.

But just flying through the air, if two yoyos are the same weight, they’ll travel in the same arc. At a miniscule level the spin velocity and air resistance will have some sort of effect if you were able to measure at that scale. Obviously two extremely different shapes (like a flying disc vs. a ball) is a whole other story, but two yoyos (ie similar basic design), I think any differences will come down to that shifty fluctuating gray area we call perception.


#10

People tends to mistake correlation for causation.

Perception of the feel of a yoyo can actually be broken down into three stages:

  1. First impression
  2. Expectation
  3. Reaction

If you think about it, the objective analysis of perception, in the case of yoyos, is actually a lot simpler than Greg is giving it credit for.

For example, on the same throw, there are only two variables that is controlled by the design of the yoyo:

  1. Distance (amount of acceleration)
  2. Time (rate of acceleration)

On the string, there are:
3. Exterior volume to mass ratio – contributes to the perceived density
4. Moment-of-inertia-to-mass ratio – completely dictates the perceived axial stability
5. Mass – contribues to the perceived inertia
5. String elasticity

As I have mentioned earlier, perception can be broken down to three stages: First impression, expectation, and reaction. Each stage is dictated by the preceding one, and gradually the effects of earlier stages will diminish as the user adapt. Ultimately, the user will settle to a certain set of control mode. What you need to do to analyze the perception is to look at this final mode and analyze its relation to the physical attributes of the yoyo itself.

PS: There is actually two types of “floatiness” that yoyoers can experience:
a) at the end of the string, and
b) on the string


#11

Hmmm… maybe the shape of the yoyo is worth considering here, with respect to aerodynamics. My thought here is that the yoyo is slicing through enough air when you consider the RPMs and not just the distance traveled. What is the average RPM of a yoyo on a throw, anyways?

And if we break the rim vs. center weight down to the concept of a tightrope walker carrying a pole for balance, that might help. Rim weight = pole with lots of weight on the ends. Center weight = pole with no weight on ends.

Also, agreed with GregP on how rim weight contributes to the stability as well as how the yoyo unrolls. Hence, the perception of rim weight = more solid, and heavy.

I’m not totally convinced that all yoyos of equal weight would follow the same arc but I want to look into that further to be sure or not. However, one component would be the same and that’s the acceleration towards the Earth due to gravity (vertical component). I’m just not sure about the lateral (horizontal) part of the arc… need more time on this than I have at the moment…

Apologies for the ramble, but I like this topic for sure.


#12

It can go as high as 60000 rpm.
In contrast, the maximum speed of a YYJ Large bearing is 50000 rpm.\

It contributes to the perceived density of the yoyo (see my post).

No.

It is fully dictated by the player’s action. Assuming no action from the player, it is uniform motion.


#13

Floatiness can also be impacted by the state of your response system. I have had a yoyo that totally thunked at the end of the string because the response was worn and slippy. After changing the response out the yo-yo gave a much more thorough and elegant wind-out returning the floaty feel that it originally had.

While this is a no brainer for most it is something to remember when you get a used yoyo in a trade. Always inspect the response if it plays unlike the preconception yu have due to the reviews and comment you have read on the web.


#14

See Greg’s and my post.


#15

I did, I didn’t see mentioned how worn the response is effecting the feel being mentioned. I read Greg mention response in his post. That could have been many different things, from what I mentioned to the response gap being too wide. Your posts did not mention response at all.


#16

#17

I definitely had the … grippiness (whether by choice of response system or age of the response)… in mind when I was talking about how quickly it gets to the end of the string or gets there with/without “thunk”, but I thought your example encapsulated it better than my brief mention. S’all good. :slight_smile:


#18

Besides “how quick” the yoyo gets to the end of the string, you also need to consider how much of the total string length was utilized to spin the yoyo up to speed.


#19

Yupyup!


#20

Which not only relates to the traction of the response but also the size and profile of the bearing. And the string. And the gap width.

In addition, the non-linearity of the acceleration caused by the geometry of the string wrapping also needs to be taken into account.

This is why I proposed that it be analyzed in two parts by the resulting observation, namely time and distance. It is quite obvious that it goes without saying the latter is dictated primarily by the response, and influenced to a lesser degree by the geometry of gap.