I don’t know where I should put this but modders seem like the people who would be most interested in this. I was thinking about what makes a yoyo unstable. The higher the center of gravity is above the string, the more it will want to fall down. But what if the center of gravity was lowered below the string… It would be the exact opposite of unstable… Crooked throws would right themselves… But how could you do it? I thought of two ways. Since the yoyo is a rotating object, any weights used to lower its center of gravity would have to also rotate. The most obvious way would be to insert marbles into the rims and give them a pipe to roll through, with some kind of lubricant to help them through. The second way would be to attach a weight to a side of a hub stack. Which would be the best way?
The marble idea seems nice, BUT
In order for this to work, the marbles would need to spin at the same times and be fastened in very tightly. Otherwise you would end up with major vibe issues. The most common and practical choice to fix this would be O-Rings, or something a bit heavier to shove in the rims, kinda like glow mods, but some sort of weight rings. Also, not sure exactly what you are saying, but the closer the weight is to the rims, the more stable it is. GOing closer to the string, or bearing seat, would make it very unstable. Correct me if I am wrong, but i have found this true throughout playing with 100’s of yoyos. Also you may be saying the exact thing, I just had trouble understanding your post.
The main amount of weight should be close to the rims, yes. However, I am talking about the center of gravity- the absolute center of mass of both sides of the yoyo, including the axle and bearing. Now, when you land a trapeze, the center of gravity will be above the string the yoyo is resting on. As the center of gravity tries to lower itself, the yoyo tilts. This center of gravity being above the string is called a reverse pendulum- incredibly unstable. Now, if we can get the center of gravity below this string, we will get a proper pendulum, which will be stable. About the vibe, as long as the marble has enough wiggle room, there won’t be any vibe- like how a floating axle prevents vibe. The main problem would be to have the marbles be slippery enough to not rotate around the rim of the pipe they are resting in. The marbles spinning would subtract from the speed of the yoyo. The other solution, having a sort of pendulum hang from a hub stack, would also subtract from speed, though. The three bearings all holding weight- the actual yoyo and the weights attached to the sides- would slow the spin about twice as fast, probably a bit less.
Without getting into all the tech talk, since I’m not a physics major:
The Square Wheels Royale is an amazingly stable yoyo. To divert for a second, this yoyo changed my mind about H-shapes. This yoyo, if throw crooked, will hold axis amazingly well, so it’s very forgiving of bad throws, letting less experienced players experience very long spin times and more time to work on their tricks(and even more time if they correct it) and reward advanced players with just awesome and amazing performance. Having said that, I hear a new Royale is in the works and ready for release soon and I cannot wait to get this item.
I think a lot that has to do with stability is in the design. After that, the throw. Take the XCon Pro, which, according to me(and a few others) is a real punk of a yoyo. If not thrown properly, man, it just spins out fast. It does not tolerate bad throws. This isn’t a weakness by any stretch. This yoyo forces you to throw better, making you a better player through this practice. Once your throw improves, the yoyo then responds very well and is a fast moving and nimble mover, although not a great grinder. I really hated this yoyo at first, then I grew to like it once I understood what was going on. Being so small with a more centered weight right, this yoyo leaves little room for error. Good or bad, like it or hate it, this is a great yoyo.
If the design is good, then you’re fine. Even if it has quirks like “throwing the darn thing properly”, which we all should do anyways. With so many different interpretations of where weight should be, inner rim design, outer rim design, weight distribution, undercuts, cut-aways and other things, it’s been shown there is no “de-facto” design. We do see many similarities based on trends, which at the moment I think is this Stepped V-shape/almost H-shape design at the moment, with lots of weight loaded at the rim, but a bit more being put in the middle to remove the nub in favor of a flat or concave for those crazy gyro tricks. Other yoyos, like the Cascade, favor more center weight, which while still stable, needs a different playing technique to avoid knocking it off axis. Nimble and agile, the Cascade, along with other center-weighted yoyos, best suit players who have a decent amount of experience to truly maximize what these great yoyos can do. I’d say any player who’s been screwing around for a while and is somewhere in the YYE Advanced 2/Expert area has more than sufficient experience and skill to be able to see how to adjust to this kind of weight distribution.
But, if your design is bad, well, there’s absolutely nothing you can do but figure out what’s wrong, why it’s wrong and then figure out how to correct the problems in the next test model.
For me, in general, V-type shapes work best. The Phenom, Equilateral, V, Firmy, Anglam are all top players for me. Stuff like the AC and Chief are also fantastic fits for me. But I’m not exclusive and I play stuff of all shapes.
Good design and stability inherent in the design helps. However, what works best for one player may be hated by another. There’s no accounting for player preferences. But, assuming a good design(I can trust YYE’s product offerings for that, as well as nearly all other retailers), the biggest factors are the throw and the skill of the player. Good design is great, but without my throw itself being decent, no amount of design perfection will save me. Fortunately, through my wide assortment of variety, my throw has improved tremendously and I can enjoy nearly any yoyo these days.
There’s very few yoyos I hate, but there are some. But why do I hate them? Mostly because they do not line up to my preferences. My preferences are towards V shapes with lots of rim weight, but as I said, I’m not exclusive to that shape and design. However, does it mean the yoyos I don’t like are bad? No, I don’t think so. I do know they aren’t a good match for me.
Your saying that if you want more stability you should just add more rim weight, right? Adding rim weight leads to a flywheel effect, which increases stability by making the yoyo more resistant to tilting, and increasing momentum and spin times by a small amount. Now, if we were to lower the center of gravity below the string the yoyo would be sitting on during string tricks, making the yoyo resist tilting would actually be counter-productive, as the yoyo would tilt into a straighter through. No horizontal work, but incredibly long spin times.
So, both the design and the throw don’t really matter. As long as the design is long spinning and ‘unstable’, the yoyo will correct itself despite the throw. Yes, in this case you want an unstable yoyo.
Making this system would cause far more problems than it would theoretically solve. For one, it would lower spin times. There is no way to attach something to stabilize the yoyos spin without adding friction, lowering spin time.
Further, any system designed to keep weights below the yoyo would mess up any horizontal, (which is increasingly becoming a standard in competitive play) and speedy play, or play with lots of directional changes, would shake the weights around.
The only real benefit would be that the yoyo would tilt less when it’s not moving, but it would lower spin times as well, meaning that it’s not good for sleeper contests. And really, tilting is easy corrected by a skilled thrower, so it’s not really an issue.
While I agree with the above post, that this can pose many problems in play these are always interesting questions to hypothesize about, at very least in the abstract. I understand the OP’s point about the moving weight and the simple if somewhat hazardous solution would appear to be having internal rings of Mercury. I’m not really jesting as much as that might make it sound. Mercury is weighty so it would achieve the desired effect, it is liquid so it could move around inside the throw (to keep the weight where the OP wants it), and actually it would cause relatively minimal frictional/motion issues compared to many liquids because it has a high surface tension. (Please don’t actually use mercury 
It’ll make you go mad and then kill you - there are plenty of polymer/alcohol things these days that do just fine as replacements!)
The other thing of course would be to simply make hyper-yoyos (I think that’s what they’re called) more efficient - i.e. to electrically enhance the spin of the throw. The faster the revolutions (with some rim weighting) the more stable the yoyo will be. Some kind of KERS (Kinetic Energy Recovery System) would be ideal!
The c3 BTH
Actually, some type of maglev bearing with a pendulum from a hub stack would theoretically not effect spin times.
And, though it is easy to correct crooked throughs, it is not as impressive to stop halfway through a trick to correct it, and there’s some tricks you can’t do this with, such as revolutions.
Regardless of weighting system (unless you’re much, much more clever than I am), it’s still going to bounce/slosh (in the case of mercury) around, making the yoyo unstable.
As for correcting tilt, you don’t need to pause. Learning how to correct tilt while doing tricks is an essential skill.
The weights would slip around, but that would still not make having the weights be a disadvantage since 70% of the time they would still keep the yoyo’s center of gravity below the string. And learning to correct crooked throws is important, but if yoyofactory would bother to make mighty flea and legend, I think it would bother to make this.
Interesting idea.
Building on Yoyo kangaroo’s pendulum idea, what about something like the vibrators in Xbox 360 controllers?
For those how haven’t found the need to disassemble theirs, here’s a pic:
http://www.modiify.com/store/images/watermarked/thumbnails/0/360/360/motors.jpg
Obviously with the motor detached. But a free-spinning unbalanced weight might just work. I’d love to see a mod of that.
The weights would have to be heavy enough to lower the center of gravity, probably 25% of the weight.
I was pondering this a bit more. How would the ‘pendulum’ be mounted to the yoyo? Possibly hubstacks?
Whipped up an example.
The pendulum is fixed to the hubstacks themselves, so it would be free-spinning and thus gravity would pull them down, [hopefully] adding stability.
Hubstacks! Brilliant way to prove concept.
any weights used to lower its center of gravity would have to also rotate. The most obvious way would be to insert marbles into the rims and give them a pipe to roll through, with some kind of lubricant to help them through. The second way would be to attach a weight to a side of a hub stack. Which would be the best way?
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You took my idea.
That should have been quoted.
Sorry, didn’t see your post.
Don’t sue, please. I’m already broke.
Haha, I hadn’t seen it either. Sorry, 'roo!