Tilted Axes, Spirals, and Dynamic Balance

[Brychanus]

Moving this here @timothy42b if you don't mind since it seemed thematically related.

Axes are increasingly weird to me to think about depending on the frame of reference being used. Don't really have a conclusion at the moment, just a link to the vids he shared with me if you hadn't stared at them yet:

First form check!

I think once you start getting closer to "flat" release with your gg move you'll find your speed will go up a little and the pendulum pump is going to help maintain tempo but the swing will feel dampened a little, which is probably much safer than just digging in and elbow locking.

www.dgcoursereview.com

Here was a link to his image:

Relationship between axis of rotation (yellow line), center of mass (pink circle), and disc trajectory (teal arrow) near moment of release from @sidewinder22.

View attachment 338508

Here was your thought about the axis:

Umm. Not saying you're wrong. But I had a somewhat different interpretation. So......

Consider the shoulder plane. It wobbles a bit during the throw, as Tread Athletics graphics show, but near release it must be fairly stable.
I would think the axis of rotation at that instant is a line perpendicular to the shoulder plane, and possibly (probably?) passing through the center of mass.

 

[timothy42b]

Thanks. I thought of putting it here in the first place, it might have fit either thread.

I didn't bring it up to be argumentative. I have recently come to think getting the disc on plane at release is a neglected but crucial topic. Advanced players probably do it without thinking but some of us struggle.

It's more obvious in forehand, maybe because the lower spin rate makes the wobble more obvious. I've been throwing more forehand on the course, because even a bad forehand helps my score.

But I'm blithely using the term "on plane" without defining mathematically what plane I'm talking about, nor how close the match has to be.

 

[Brychanus]

I think e.g. the Overthrow video on planes or Philo's "tips for throwing flat" give a reasonable representation of talking about one kind of plane, or at least how some people think about or demonstrate it. Is that "right"?

My own sense is that the plane will always tend to get a bit more complex in reality as the motion gets more advanced like in the "not straight and flat" thread. I'm not sure if my own motion should ever be a reference point, but the slightly weird stuff my body learned to do from all the drills and throwing means that there's a lot more wave-like and torquey stuff going on in the motion than I ever expected. It ends up looking smooth but there's all kinds of interesting forces and interactions in there. The most surprising stuff was completely unintentional and just started to happen on its own as my motion changed. There was also no way to know how it would feel in advance. It doesn't feel or work quite like most of the "plane drills" people share (for me). Dunno if it's just me or just because I didn't learn by using them.

The overhand golf images sidewinder shared were immediately cool and new brain candy to me because I guess one takeaway I have is that as real biological motions get more advanced, they get more fluid and organic while also putting the force chains in new places, and "rotation" becomes a weird concept depending on the frame of reference I guess. So your questions are interesting IMHO and I don't have a great answer myself.

 

[timothy42b]

I think e.g. the Overthrow video on planes or Philo's "tips for throwing flat" give a reasonable representation of talking about one kind of plane, or at least how some people think about or demonstrate it. Is that "right"?

My own sense is that the plane will always tend to get a bit more complex in reality as the motion gets more advanced like in the "not straight and flat" thread.

I'm about to re-read the No Flat Swing thread. It occurs to me that if the disc is spinning without wobble, and it is nose up or nose down at all, the plane of the throw must not quite match the plane of the spin. ??

 

[Brychanus]

I'm about to re-read the No Flat Swing thread. It occurs to me that if the disc is spinning without wobble, and it is nose up or nose down at all, the plane of the throw must not quite match the plane of the spin. ??

I actually think we even see evidence that there are some differences all the way at the top of throwers.

E.g., GG or Simon seems to a throw "on plane"/low off-axis torque by the time the disc is coming out of the pivot/high spin/low wobble. GG achieves this with pretty US (for mortals) discs. But the action out of the backswing into the pocket and then release has all of the interesting redirections as the whip through is evolving. GG still looks like the most "centrifugal" thrower we've ever seen and has a huge but it's always interesting that the profile of actions and disc redirections from peak of reachback to release is similar:

In contrast, Wiggins has often violent initial wobble on OS (for anyone) discs that stabilizes in flight. Watch the action of the disc as it is exiting the pocket but before the release here:

Since I've been working on onboarding a bit more "GG-lite" mechanics there's definitely some weird new force interaction coming through the pocket, and more of a spiking acceleration in release.I finally got the green and white imaginary force lines to "connect" today in my move. I wouldn't generalize just from me and I'm not positive how I could know if it's actually part of how GGs works, but I found it interesting that it worked out for me today.

My move looks smooth and kind of slow until almost the very last part, then this burst happens:

Look for the "push the quarter on the tabletop"/drop the hammer. There's this enormous force that suddenly comes through my hand and you can see the disc "drop" as my plant leg resists the ground:

Big acceleration/snap/"explosive" looking spike for "free" in the move. My disc is in the pocket, starts to redirect out, then BOOM it's gone. Fascinating. I had to be careful today to make sure I was landing postured well enough that my arm was following through safely.

 

[itlnstln]

I'm about to re-read the No Flat Swing thread. It occurs to me that if the disc is spinning without wobble, and it is nose up or nose down at all, the plane of the throw must not quite match the plane of the spin. ??

Not necessarily, and I think it has something to do with gyroscopic precession or whatever TF that Pete Ulibarri video was demonstrating. My understanding is that wobble is evident with the axis of spin isn't the center of the disc; nose up or down can still be on-axis. A better example is your arm and body is throwing an anhyzer and the disc in a hyzer orientation.

Imagine your shoulders and arm are rotating on flat plane and you're holding the disc in the "briefcase" position all the way through the hit, this would be an ([Mountain Dew Voice]: EXTREME!) example of OAT and the disc would wobble (or not fly at all in this example). The discs rotation of axis is the edge of the disc, not the center of the flight plate. Really, I suspect all we need to account for is ensure the forearm and disc are on the same plane through the hit if we're concerned only with wobble. This is somewhat supported by the examples Brychanus posted of GG and Simon.

If you want to see OAT very clearly, look at slow motion footage of Ohn Scoggins' and Missy Gannon's putts. You can see in Ohn's putt that the disc sags down in her hand. It's kind of like her arm is flat and the disc is in a hyzer position

I actually think we even see evidence that there are some differences all the way at the top of throwers.

E.g., GG or Simon seems to a throw "on plane"/low off-axis torque by the time the disc is coming out of the pivot/high spin/low wobble. GG achieves this with pretty US (for mortals) discs. But the action out of the backswing into the pocket and then release has all of the interesting redirections as the whip through is evolving. GG still looks like the most "centrifugal" thrower we've ever seen and has a huge but it's always interesting that the profile of actions and disc redirections from peak of reachback to release is similar:

In contrast, Wiggins has often violent initial wobble on OS (for anyone) discs that stabilizes in flight. Watch the action of the disc as it is exiting the pocket but before the release here:

Since I've been working on onboarding a bit more "GG-lite" mechanics there's definitely some weird new force interaction coming through the pocket, and more of a spiking acceleration in release.I finally got the green and white imaginary force lines to "connect" today in my move. I wouldn't generalize just from me and I'm not positive how I could know if it's actually part of how GGs works, but I found it interesting that it worked out for me today.

My move looks smooth and kind of slow until almost the very last part, then this burst happens:

Look for the "push the quarter on the tabletop"/drop the hammer. There's this enormous force that suddenly comes through my hand and you can see the disc "drop" as my plant leg resists the ground:

Big acceleration/snap/"explosive" looking spike for "free" in the move. My disc is in the pocket, starts to redirect out, then BOOM it's gone. Fascinating. I had to be careful today to make sure I was landing postured well enough that my arm was following through safely.

Not sure if this was or is true, but I remember Blake mentioning on DGR that distance throwers purposely throwing discs with OAT to get the nose down on high-trajectory, distance line throws. Anecdotally, this tracks. If you get a significant amount of OAT/wobble on a disc, it'll turnover

 

[Nick Carroll]

As a person who is really, really, good at creating wobble on discs - albeit unintentionally - it more effects the initial fight of the disc than the later parts of it, since gyroscopic forces stabilize the disc in flight the farther it travels. So increased wobble will make a disc flip up more, and alter the flight due to that initial (less stable) first part of the flight.

In my experience nose up doesn't necessarily make the disc less stable, or wobble more in flight. It has more of an effect of making a disc more stable because of the initial drag, and distance loss will occur due to the disc "air bouncing" early in it's flight, and fade earlier towards the end of it. That said, nose up throws, and anything else that causes wobble, will tend to reduce the distance the disc will travel.

I think this effect is largely ablated if the disc hits the right angle once stabilized. But the relatively deep hyzer throws at high speed and spin, that flip up and carry, will largely be stabilized by the time they reach a better angle in the air, to be carried by the wind.

 

[timothy42b]

In contrast, Wiggins has often violent initial wobble on OS (for anyone) discs that stabilizes in flight. Watch the action of the disc as it is exiting the pocket but before the release here:

Good find. In the yellow shirt Wiggins video, this is what I think I see.

Intersecting lines define a plane, so the bent arm defines one plane and it isn't the same as the shoulder plane. The disc plate is on that plane from the pocket to the hit. Relative to the arm, the disc is moving west and down.

But at the same time the shoulder is moving up and east. That causes the resultant direction of the disc to be north and a little up, but the disc plate is still oriented down and disc rotation plane is slightly down and west. Since the force forward and up is at the edge of the disc rather than the COM, some wobble is nearly inevitable.

The shoulder plane precesses, the arm plane translates I think.

 

[BenjiHeywood]

As a person who is really, really, good at creating wobble on discs - albeit unintentionally - it more effects the initial fight of the disc than the later parts of it, since gyroscopic forces stabilize the disc in flight the farther it travels. So increased wobble will make a disc flip up more, and alter the flight due to that initial (less stable) first part of the flight.

I think high initial wobble would actually have an effect on the end of the flight, as well as that initial bit of extra turn. I'm pretty sure that the forces that act to damp the wobble will reduce the spin rate, and a lower spin rate through the rest of the flight will obviously impact the turn/fade behaviour. But I've no idea how big the effect would be.

I guess @Eric_T might be the man to ask on the physics stuff. Am i right that damping wobble costs you spin?

If so, it would be really interesting to be able to access the back-end of a techdisc, and persuade it to record the metrics again a few metres into the flight and see how big an effect wobble has on the ability to maintain spin.

 

[sidewinder22]

IDK that wobble really turns the disc over more, I think it keeps it moving straighter as the CoP is moving all the way around the disc so it kind of cancels out a lot of the precession in one direction or the other. Easier to see on putts like Scoggins and Rico with their wobble putts that go dead straight, and don't really turn or fade like a low wobble putt does.

I think wider rim discs have two things that help dampen/stabilize wobble quicker, 1. is the aerodynamic profile/sharper wing and drag, and 2. is the mass distribution/gyro effect.

IIRC the wobble rate is 2x the spin rate, but IDK that dampening the magnitude affects the spin rate or how it affects. I also read somewhere that drag doesn't really slow spin rate much, not sure if true or how true.

 

[Nick Carroll]

In my experience editing hundreds of disc golf videos and throwing with a lot of wobble, I personally believe it will make a disc turn over quicker, but as the disc flies farther, the wobble decreases and the turning aspect diminishes over time. I don't have anything scientific other than watching discs fly that way, but it makes for more S-curve style flights. This phenomenon is more visible on putters.

I used to get full S-curves out of Darts with my backhand throw because I produced so much wobble they turned quickly, and if thrown high enough and they don't roll over, they'll slow down in flight and then fade. And these didn't go more than 200 feet at best. Someone with smooth form and little to no wobble can throw a Dart dead straight much farther. I can actually throw them 200' much straighter now, than I did 2-3 years ago when I threw them a lot, because I've spent a lot of time working to specifically minimize wobble.

I know this is totally anecdotal, but I have higher wobble numbers than most, and I've done a lot of throwing that way for years now.

 

[sidewinder22]

In my experience editing hundreds of disc golf videos and throwing with a lot of wobble, I personally believe it will make a disc turn over quicker, but as the disc flies farther, the wobble decreases and the turning aspect diminishes over time. I don't have anything scientific other than watching discs fly that way, but it makes for more S-curve style flights. This phenomenon is more visible on putters.

I used to get full S-curves out of Darts with my backhand throw because I produced so much wobble they turned quickly, and if thrown high enough and they don't roll over, they'll slow down in flight and then fade. And these didn't go more than 200 feet at best. Someone with smooth form and little to no wobble can throw a Dart dead straight much farther. I can actually throw them 200' much straighter now, than I did 2-3 years ago when I threw them a lot, because I've spent a lot of time working to specifically minimize wobble.

I know this is totally anecdotal, but I have higher wobble numbers than most, and I've done a lot of throwing that way for years now.

I think it has more to do with where you are directing force(form) than the wobble itself causing it to turn.

 

[Nick Carroll]

I think it has more to do with where you are directing force(form) than the wobble itself causing it to turn.

That could be. Admittedly I'm no authority here, and I may be missing things that aren't obvious to me.

 

[BenjiHeywood]

IDK that wobble really turns the disc over more, I think it keeps it moving straighter as the CoP is moving all the way around the disc so it kind of cancels out a lot of the precession in one direction or the other. Easier to see on putts like Scoggins and Rico with their wobble putts that go dead straight, and don't really turn or fade like a low wobble putt does.

I think wider rim discs have two things that help dampen/stabilize wobble quicker, 1. is the aerodynamic profile/sharper wing and drag, and 2. is the mass distribution/gyro effect.

IIRC the wobble rate is 2x the spin rate, but IDK that dampening the magnitude affects the spin rate or how it affects. I also read somewhere that drag doesn't really slow spin rate much, not sure if true or how true.

Interesting. I feel like if there is any effect of wobble straightening putts (which is an interesting brand new idea to me) it wouldn't be a strong enough thing to straighten a higher-speed throw.

In ultimate, i remember a really interesting coaching session with a guy whose throws matched mine very closely downwind (same distance, height, turn, same amount of late fade etc) implying very similar spin and speed, but his upwind throws turned and burned almost immediately. Slow motion footage showed much more wobble for him. I've always been convinced that wobbly has a very appreciable effect on early turn.

 

[mostlynorwegian]

Beautiful manna to my ears.
Disc golf is a playground for other sports, and movement based activities to integrate from as it is about taking and creating energy from a point of balance. Where a lot of what is mentioned with skiing, bicycling, skateboarding, etc. is also distinctly utilizing the shaping of the land itself for the body to create the intended point of velocity.
I also don't get why the usual barrage of form videos that get linked then goes to show EVERY THING where the legs are just on a flat surface, and never really that far off axis so as to compromise balance if anything were to distract them.

 

[sidewinder22]

Interesting. I feel like if there is any effect of wobble straightening putts (which is an interesting brand new idea to me) it wouldn't be a strong enough thing to straighten a higher-speed throw.

In ultimate, i remember a really interesting coaching session with a guy whose throws matched mine very closely downwind (same distance, height, turn, same amount of late fade etc) implying very similar spin and speed, but his upwind throws turned and burned almost immediately. Slow motion footage showed much more wobble for him. I've always been convinced that wobbly has a very appreciable effect on early turn.

You mentioned wind so is it due to precession or is it sailing?

 

[BenjiHeywood]

You mentioned wind so is it due to precession or is it sailing?

It definitely flips/turns, ie left edge rises and right edge falls (for rhbh).

 

[sidewinder22]

Could it be that nose is nodding more down? Or is actually released more nose down.

Not sure how to really isolate the wobble from nose or average nose.

 

[BenjiHeywood]

Could it be that nose is nodding more down? Or is actually released more nose down.

Not sure how to really isolate the wobble from nose or average nose.

I think the nose goes both up and down. I don't think the 'average nose' is generally different on a wobbling vs non-wobbling throw. But i don't have data, obviously.

Another anecdotal thing from ultimate. Releasing very low to the ground - often as low as 4-6 inches release height, where the wind is much lower - is a very good way to throw upwind even if the throw then goes up higher, into the teeth of the wind. The received wisdom is very much that the initial wobble is happening in the low-wind, lower-airspeed phase and has been damped before the disc is exposed to the stronger wind. The same throw, thrown from waist height or above, would be much more likely to burn over due to that initial wobble.

Again, i don't know of any data on that, but it's definitely the received wisdom in ultimate that you're better off releasing low in headwinds, even if that means you need slightly more nose-up and show some of the flight plate to the wind.

 

[Eric_T]

I think high initial wobble would actually have an effect on the end of the flight, as well as that initial bit of extra turn. I'm pretty sure that the forces that act to damp the wobble will reduce the spin rate, and a lower spin rate through the rest of the flight will obviously impact the turn/fade behaviour. But I've no idea how big the effect would be.

I guess @Eric_T might be the man to ask on the physics stuff. Am i right that damping wobble costs you spin?

If so, it would be really interesting to be able to access the back-end of a techdisc, and persuade it to record the metrics again a few metres into the flight and see how big an effect wobble has on the ability to maintain spin.

I haven't looked at the wobble part of the dynamics yet, but it's a really interesting question. The wobble definitely means that angular momentum is transferred between the axes, but not sure if you can say that you need to take momentum from the spin to damp the wobble. But the off-axis torque could initially have been used to give the disc more spin instead, so you definitely lose something there.

I am trying to set up a simulation now of how the wobble affects the aerodynamics, so should have some data there soon. My guess would be that the wobble doesn't create extra turn, and that it has more to do with release angle being thrown off, but we will see.