Tilted Axes, Spirals, and Dynamic Balance

[Brychanus]

You may be, more generally, i couldn't say. But it's a safe bet that you're right on this one. There's no way that wobble, with additional drag, can add distance potential, unless perhaps the lift associated with wobble-drag was somehow way stronger than ordinary smooth-flight lift. Which seems highly unlikely, to say the least.

Yes, but where is the perceived distance increase conversation coming from, (Tech Disc or science)? Real world examples of more turn caused by wobble are nearly imperceptible because BH wobble is typically dampened before you can see any effect on turn and significant FH wobble seems to quickly increase fade.

I guess I'm imagining two players and both are in real-world situations:

1. A new player with low armspeed who is putting a lot of OAT/wobble on the disc at release. It turns the "overstable" disc into a turning disc early in flight. The player concludes that some discs are "too understable" for them. If instead they had low-wobble throws they would potentially learn different habits and make different conclusions.

2. @CoachChris may have something specific to say there in this case. A very advanced player like Wiggins who at some (and of course it appears to vary) had high-wobble throws on things like a Boss, which should initially somewhat slow the disc with drag but also send it into more turn initially. With a 85mph release once the wobble dampens, the disc is still moving so fast that great distance is achieved. I suppose what Chris is suggesting is that whatever bit of turn is happening early on due specifically to wobble may end up being negligible in a real-world context, but I'm raising it because I am curious, as usual.

Then for the sake of contrast, you have someone like GG where there are now actual data that he achieves low wobble, high spin rate throws such that even though he throws "only" in the mid-70s mph, he is not suffering the early drag from the wobble (@CoachChris) while throwing relatively understable discs that naturally have a pronounced gyroscopically stable turn phase when thrown well.

 

[CoachChris]

2. @CoachChris may have something specific to say there in this case. A very advanced player like Wiggins who at some (and of course it appears to vary) had high-wobble throws on things like a Boss,

David is not a good example in discussing wobble because having seen many of his throws in HD super slomo (and still hard to see) I think he may be stretching/distorting/elongating the disc going into release and not just adding OAT. (The disc seems to deform)

 

[Brychanus]

David is not a good example in discussing wobble because having seen many of his throws in HD super slomo (and still hard to see) I think he may be stretching/distorting/elongating the disc going into release and not just adding OAT. (The disc seems to deform)

Now that's also fascinating.

 

[BenjiHeywood]

David is not a good example in discussing wobble because having seen many of his throws in HD super slomo (and still hard to see) I think he may be stretching/distorting/elongating the disc going into release and not just adding OAT. (The disc seems to deform)

An excellent point. I'd be astounded if he wasn't deforming it. I've seen pics of ultimate discs distorting when thrown, and whilst they're a bit bigger and less dense, they're also not thrown at 85mph. I can't find a good photo just now.

I think the split-second distortion of a disc is massively more than we would ever see from the naked eye.

This photo is of a block, not a throw, so not really comparable in some ways, but you'd never guess in real time how massively deformed the disc gets at the moment of impact.

 

[itlnstln]

An excellent point. I'd be astounded if he wasn't deforming it. I've seen pics of ultimate discs distorting when thrown, and whilst they're a bit bigger and less dense, they're also not thrown at 85mph. I can't find a good photo just now.

I think the split-second distortion of a disc is massively more than we would ever see from the naked eye.

This photo is of a block, not a throw, so not really comparable in some ways, but you'd never guess in real time how massively deformed the disc gets at the moment of impact.

View attachment 339814

Good point. If you just hold a disc loosely in front of you, then grip it hard, you can see that it deforms pretty easily even fairly stiff plastic. When I clamp down, my thumb pushes the wing down some. I would imagine that could create wobble if it shifts the axis enough

 

[Brychanus]

There's also potentially the linear distortion/literal stretch of the disc in some forms - like Wiggins' possibly places a large effect on it as part of the horizontal abduction phase of his move.

 

[Eric_T]

I don't have an awful lot to add to the conversation just now, but i couldn't let this pass without saying how completely incredible it is that you're doing this. Thank you!

This is surely publishable research if you wanted to, right? I've never seen wobble dealt with properly in the literature.

I lied, i actually do have a question, now that i think about it.

We've talked a bit (not sure if in this thread or another) about the beating-in of a disc and what it is that might make it turn more. I wonder if this result impacts that discussion?

A common theory is that the lip gets bent down when a disc hits things, and/or that the bottom of the disc is scraped off - both of which lower the effective parting line height. As i said before, i personally think the rim would be bent both up AND down when the disc hits things - and if that were the case, could this asymmetry you've found in the effect on the moment explain the fairly slight additional turn we see?

Thanks, I really appreciate it! Yes, I could probably publish something on this, and I have been thinking about writing something like a summary of all the discussions here, but that requires a lot more rigor and attention to detail, haha. It's nice to have some outlets for my work which is more casual. So thanks a lot for the questions and comments!

I still think the beating-in effect is more subtle and tricky to describe. As you say, there are many factors coming into play. You could look at each factor in isolation, but I think to see how the effects actually develop over time and the importance of each factor would require some in-depth measurements and a lot of patience.

 

[sidewinder22]

But we clearly see that the oscillation is not symmetric, the moment drops more when the nose is down compared to how much it increases when the nose is high during the wobble. This means that the net effect will be increased turn compared to no wobble.

This makes sense, so if the disc was symmetric, top and bottom like a CD we wouldn't see the asymmetry in the precession with wobble.

This comes in addition to the fact that off-axis torque will reduce the spin rate.

Is this a fact? I'm not so sure with how the human body works.

 

[jupiterboy]

Smooth, clean hyzer with an understable disc will be more stable. Wind obv., but practicing keeping a flippy disc on hyzer is informative and beneficial from my perspective. You can almost craft any shot with an understable disc, it's just harder, and the wind might take some of those shots away.

I'm kinda on the fence about beating in discs. I was on that for a while, and beat some in, then lost some. You end up with this unicorn disc that can't be replaced. Still, even steady plastic like Z relaxes into a normal state. Change.

 

[itlnstln]

I'm kinda on the fence about beating in discs. I was on that for a while, and beat some in, then lost some. You end up with this unicorn disc that can't be replaced. Still, even steady plastic like Z relaxes into a normal state. Change.

In ye olde days, I used to carry 3-4 of the same mold in different states of wear. This was a time when there was really only Innova, Discraft, and Gateway (and some off-shoots like DGA and, later, Discmania). These days, there are so many molds in great plastic with (mostly) better consistency that it's easier to build a bag from stock, premium plastic than wait for that KC Pro Roc to beat in juuuuuust right

 

[Nick Carroll]

I did some fieldwork a couple years ago with my forehand throws, as I was starting to learn how to throw them. I saw in slow motion the disc deformed quite a bit during my swing, which created even more wobble. The more rigid plastics help, but it still happens with them. But the softer ones are the easiest to see this happen. That said, the smoother the swing, the least deformation happens. This is one of the reasons I advocate for as much of a flat swing plane as possible. From the peak of the backswing, to the release of the disc if possible, as that minimizes any distortion of the disc. This is also why I'm not a fan of the suitcase grip or other things that happen prior to the power pocket. Even if the disc is corrected by the time it comes through the power pocket.

 

[Nick Carroll]

This makes sense, so if the disc was symmetric, top and bottom like a CD we wouldn't see the asymmetry in the precession with wobble.

Is this a fact? I'm not so sure with how the human body works.

This response by Sidewinder to Eric's "off-axis torque will reduce the spin rate" statement. I think the wobble creates drag, which can't help but slow the disc down, at least initially, as well as reduce the spin rate in that initial period of time. I think if you watch a disc's flight as it stabilizes, you'll see the wobble go away fairly quickly. But the drag already happened at the beginning of the disc's flight. This is my understanding, at least, as a layman.

 

[BenjiHeywood]

@sidewinder22 Here's a thought. Imagine a disc spinning completely on edge like when you spin a coin on the table. It surely experiences significant drag which works to reduce the spin rate.

There's a continuum between spinning entirely on-axis in a clean flight, through a bit of wobble, then a lot of wobble, then eventually spinning more like a coin on a table. I don't have much of a clue what the graph of wobble versus spin-drag would look like, but I'm confident it would be at a minimum when the disc has no off axis torque and a maximum when spinning on its end. In between - a disc with a bit of wobble - would then experience a little bit more spin-drag than the zero OAT throw. I don't know how much obviously, it might be negligible, but wobble must cost you spin.

The question of whether the mechanism of damping costs you more spin directly, I'm not sure i know enough to work out. I dunno if a disc wobbling in a vacuum would have its wobble damped or not, and if it does, whether the spin would decline as a result. But I'm pretty sure that, in air, wobble must cost you some amount of spin (whether large or small i dunno).

 

[Eric_T]

This makes sense, so if the disc was symmetric, top and bottom like a CD we wouldn't see the asymmetry in the precession with wobble.

Is this a fact? I'm not so sure with how the human body works.

I meant in the sense that the torque you would impart on the disc to give it spin would instead be used off-axis, assuming conservation of momentum. But you are right, with biomechanics we cannot definitely say that momentum is conserved in this sense.

 

[Nick Carroll]

More things I've been thinking about regarding off-axis torque reducing speed and spin rate. I think this also applies to deformed discs.

1) There can be drag in any direction, including in a circle. A rotating disc that is deformed will have drag against the angular momentum, so that should slow the spin rate as well. A deformed disc should also travel slower in any direction, including as it rotates.

2) Also deformed discs should be less stable in flight. We beat in discs and they become less stable because they are deformed. That's incontrovertible. Why would a disc that wobbles not behave the same way? If a disc is rotating on it's center axis, but is deformed, it should also experience drag.

So to me at least, I'm at peace with the idea that speed and spin are reduced due to either a) off-axis torque, and b) deformed discs (not just deformed due to change in direction of the swing, but permanently deformed due to wear or defect).

 

[sidewinder22]

David is not a good example in discussing wobble because having seen many of his throws in HD super slomo (and still hard to see) I think he may be stretching/distorting/elongating the disc going into release and not just adding OAT. (The disc seems to deform)

Now that's also fascinating.

That is part of my goal when throwing far - to elongate/stretch the disc out longer with acceleration. It's also why I like swinging the Flexbar around, it gives you a little lag/spring/whip feeling to it.

Instead of the hammer you can use a plain ole stick or something like the flexbar I use in Don't Spill the Beverage. The flexbar gives you a little spring action which I like, almost like warping the disc.

 

[jupiterboy]

I've wondered if there's a phase aspect to any OAT or distortion of the disc where it may wobble, return to true, then express the wobble again—like the oat expresses in waves of stored energy. I wonder if this has anything to do with when a disc turns. Hard to know with variable wind conditions, but I thought a backhand turnover the other day was starting to get right then started a second phase of turn.

 

[Brychanus]

That is part of my goal when throwing far - to elongate/stretch the disc out longer with acceleration. It's also why I like swinging the Flexbar around, it gives you a little lag/spring/whip feeling to it.

I still mess with that sometimes and it was maybe the best purchase next to my throwing sledge.

It's kind of weird on the disc because the best throws always seem like they have that weird combination of "corkscrewing" into and out of the backswing/screwing the jar effect, plus possibly whatever the elongation stretch effect you & Taylor mention here. I can identify and manipulate both in the Flexbar.

I'm impressed that it seems like it doesn't even need to be very big to work as long as it is connected to the ground forces. E.g., I threw a couple standstills focusing on the "flexbar effect" with a small shift this morning and it was clear that it was some significant percentage of the power at low effort. I think that's maybe the "same" effect in X-step/hop as what defines whether I get a full hit & flight on the heavy Comets I like to throw vs. not. Lots of fascial load & unload, stretch reflexes all working together, etc etc. Probably the young and very mobile people are maxxing out on that dimension in ways I never will, but it's cool that it's possible to tap into with less nimble movement, too.

Also part of what I now like to think of as the "holistic" part of the move in the windup - it seems like you either build up and get all that torque vibing together from the ground up including the arm, or you don't. I do think there's some tolerance for slop in the body and balance since mine is far from perfect, but the better the windup, the better it just kind of.... works. If it's not, I'm working harder and usually throwing less well. So focusing on overall "windup quality"/whole body Flexbar effect is a helpful heuristic in my case right now.

 

[jupiterboy]

 

[yossarian]

This came across my newsfeed recently and I immediately thought of this thread. I wonder if any top level shot putters have played disc golf?

https://www.cbc.ca/sports/olympics/summer/trackandfield/sarah-mitton-shotput-canadian-record-may-12-1.7202094