What's really so bad about OAT's?

[Blake_T1]

good example BU.

 

[BlarneyStoner]

As for OAT and the stability of discs. It's typical for new throwers to roll their wrist over or get off plane because they're unfamiliar with proper form. They typically start with 1-2 discs and they get beat up pretty quickly. Thus, they believe that those discs are now too understable for them. They then go and look for a disc that's more stable, thinking that the previous one is too understable for their power. They could just go buy a new version of the same disc. Now, they find with the new, more stable disc, that the discs don't go as far, so they throw harder, causing more lack of control and more OAT and wrist roll.

Wow... that is exactly what I've just realized I've been doing. I started turning over Surge's (RHFH) as I started to try to generate more power. I have thrown them in the 275-300ft range for some time and have been trying to break that plateau. I thought it was the disc, so I went out and bought a couple new ones that would give me some more stability. Same effect. It looks like I'm throwing with quite a bit of OAT, and that's causing the disc to fly a lot more HS understable. Does that sound right?

 

[black udder]

As for OAT and the stability of discs. It's typical for new throwers to roll their wrist over or get off plane because they're unfamiliar with proper form. They typically start with 1-2 discs and they get beat up pretty quickly. Thus, they believe that those discs are now too understable for them. They then go and look for a disc that's more stable, thinking that the previous one is too understable for their power. They could just go buy a new version of the same disc. Now, they find with the new, more stable disc, that the discs don't go as far, so they throw harder, causing more lack of control and more OAT and wrist roll.

Wow... that is exactly what I've just realized I've been doing. I started turning over Surge's (RHFH) as I started to try to generate more power. I have thrown them in the 275-300ft range for some time and have been trying to break that plateau. I thought it was the disc, so I went out and bought a couple new ones that would give me some more stability. Same effect. It looks like I'm throwing with quite a bit of OAT, and that's causing the disc to fly a lot more HS understable. Does that sound right?

Maybe, maybe not. If you're throwing RHFH (sidearm), then you will get a lot more snap on the disc than a typical backhand. It's not uncommon for newer players to sidearm a disc 300', but backhanding a disc 300' is a bit tougher.

With sidearm, you get a LOT of snap on the disc which will turn over discs that are not too overstable. A Surge could be one of these discs that isn't good for sidearm (I can't sidearm so can't say much). I know the sidearm players I know throw things like Monsters. You can check out the equipment threads for good sidearm discs, or quote your average distance and ask some of the guys what they recommend.

What I was talking about would mean that you threw the Surge at the start and it did just what you wanted, and as it got older, you started to flip it, so you bought a more overstable disc and then it was too overstable.

 

[BlarneyStoner]

What I was talking about would mean that you threw the Surge at the start and it did just what you wanted, and as it got older, you started to flip it, so you bought a more overstable disc and then it was too overstable.

That's what happened. I used to throw nice 300ft shallow S's with it. 325 on a really good throw, released with a little anny. Now, more often than not I'm geting a 175-200ft 1/2-S, intead of the S. I think I'm giving the same amount of height I used to, in order for it to have the time to flex out. I just don't feel like I'm getting that strong whipping motion that I used to on the sidearm, but I don't know what I've changed.

 

[BlarneyStoner]

so you bought a more overstable disc and then it was too overstable.

Oh... sorry, just caught this part. I did wind up buying newer Surges to compensate for what I thought was a beat understable disc. The result was not too much overstability, but the same lack of HS stability- imparted, I'm starting to believe, by my inability to direct all of my power around the axis of my throw.

 

[Blake_T1]

With sidearm, you get a LOT of snap on the disc which will turn over discs that are not too overstable.

it's actually velocity that turns discs over... snap does not.

people who have cannons for arms have a lot of velocity, hence the need for stability.

most players who bomb have very little off axis torque.

 

[freeus]

This is a very illuminating discussion. I always thought that off-axis torque meant the disc fluttering like an unbalanced tire while it flies (which mine also do sometimes) . But based on what's been said here, I have a huge OAT problem. Thanks for the info, I have something to work on.

 

[cmlasley]

This is a very illuminating discussion. I always thought that off-axis torque meant the disc fluttering like an unbalanced tire while it flies (which mine also do sometimes) . But based on what's been said here, I have a huge OAT problem. Thanks for the info, I have something to work on.

The flutter can be a symptom of OAT.

 

[Olorin1]

I'm also trying to understand OAT better. I'm not really clear about what axis you're talking about. To me, the initial explanation was unclear. A picture would really help here, but I don't know how to post a good one. Here are 2 attempts:
-Look on the first page of this article http://www.discwing.com/pdf/ARCpaper.pdf for the X-Y-Z axes on a disc
-On this page, http://sites.google.com/site/discphysics/Home/axes, there's an attachment that has the same picture of just the disc with the X-Y-Z axes.

OK, so lets try with just words. Assume that the disc is flat and the forward velocity vector is pointing on the X axis. Then the Z axis runs vertically through the center of the disc. The Y axis is on the same plane as the disc and perpendicular to the X axis.

OR: looking down on the disc, the front is at 12:00 so the X axis runs between 12:00 and 6:00 and the Y axis between 3:00 and 9:00.

If someone could figure out how to post those pictures here it would be much easier to visualize.

Back to OAT-- I'm guessing that OAT is along the Z axis. Is that right?

 

[JR]

Tired after work so let's see if my brain has shut out. If the disc is flying along X axis it would rotate on Y axis thanks to the spin. Rotation anywhere else than on the Y axis would be off axis torque. That's why there's the off there. The disc would still rotate around the center but it would also have other forces going to different directions acting on the disc=flutter.

 

[Olorin1]

Actually, the disc is spinning on the X-Y plane while it rotates around the Z axis. It may be easier to think of airplane first. See this page on Flight Dynamics. The nose on the airplane is pointing in the same direction that the disc is flying. There are 3 aerodynamic parameters: Pitch, roll, and yaw.
Roll = Left or right side higher. Along X axis
Pitch = nose up, nose down. Along Y axis
Yaw = the spin on a disc. Along Z axis

 

[JR]

Actually, the disc is spinning on the X-Y plane while it rotates around the Z axis.

True dat. As I said I was dog tired. And any deviation of the spin from the X-Y plane is OAT. The nose of the disc can still be down or up and still spin like a flat front vs rear of the disc would without OAT. But that isn't usually good. There are also some often usable good forms of OAT. When they are planned to be utilized. Longest throws are annied steeply after the apex and the nose can be 80 degrees down on the disc rim and the disc falling from the sky. To get annied so much that the nose is so much down and having enough altitude that the disc will flex to flat and glide forward late in the throw may well need intentional OAT to have the disc flip to enough anny for the disc to avoid stalling at those high altitudes.

 

[garublador1]

Back to OAT-- I'm guessing that OAT is along the Z axis. Is that right?

You're part way there. Torque is a rotational foce about an axis. You are correct that it is about the Z axis in the coordinate system you have set up. Off-axis torque is any torque that is about an axis other than the Z axis. This off-axis torque will be a vector with a magnitude and a direction. Think of it as an arrow originating from (0, 0, 0) in your example pointing away from the disc in the positive Z direction, but not directly along the Z axix. The length of the arrow is the amount of torque you are applying. The direction of the OAT will have three components that can be expressed as an angle with respect to the X axis an angle with respect to the Y axis and an angle with respect to the Z axis. The component that's in the X axis is what we're talking about. It will cause the disc to act more or less "stable" than a clean throw.

There may also be a Y component that can change the pitch. For example, wrist extenstion can cause some OAT with a component in the Y direction that will cause more nose down. This type of OAT is generally not talked about a lot. It's more that people talk about things, like wrsit extension, causing more nose down, not causing OAT.

 

[Olorin1]

So, using the airplane analogy, the most common OAT is roll about the X axis so that the left side of the disc is higher and the right side is lower. Is that correct?

If the spinning disc is the XY plane then the disc spins about the Z axis. It seems to me that if you tilt the XY plane then the Z axis still stays perpendicular to the XY plane. Would you agree with that? If that's correct, then when you roll the disc so that the left side is higher, then the Z axis also tilts away from vertical to stay perpendicular to the plane of the disc. Would you agree with that too?

 

[Olorin1]

Who invented the term "Off Axis Torque"? It sounds like something Blake would say.

 

[garublador1]

So, using the airplane analogy, the most common OAT is roll about the X axis so that the left side of the disc is higher and the right side is lower. Is that correct?

Again, sort of. It's not about which side is higher, it's about how force is applied to the disc. You're right that the result is a force that pushes the left side higher.

If the spinning disc is the XY plane then the disc spins about the Z axis. It seems to me that if you tilt the XY plane then the Z axis still stays perpendicular to the XY plane. Would you agree with that? If that's correct, then when you roll the disc so that the left side is higher, then the Z axis also tilts away from vertical to stay perpendicular to the plane of the disc. Would you agree with that too?

You're right about the result, but again, it's about forces on the disc, not about disc orientation. If you throw with the left side higher that's, by definition, an anhzyer throw and doesn't say anything about the torque applied to the disc. OAT would be if you threw on a flat or hyzer line, but applied torqure about an anhyzer angle.

 

[mark12b]

If the spinning disc is the XY plane then the disc spins about the Z axis. It seems to me that if you tilt the XY plane then the Z axis still stays perpendicular to the XY plane. Would you agree with that? If that's correct, then when you roll the disc so that the left side is higher, then the Z axis also tilts away from vertical to stay perpendicular to the plane of the disc. Would you agree with that too?

off-axis torque would be when the z-axis of your throwing motion doesn't match the z-axis of the spinning disc.

 

[Olorin1]

If the spinning disc is the XY plane then the disc spins about the Z axis. It seems to me that if you tilt the XY plane then the Z axis still stays perpendicular to the XY plane. Would you agree with that? If that's correct, then when you roll the disc so that the left side is higher, then the Z axis also tilts away from vertical to stay perpendicular to the plane of the disc. Would you agree with that too?

off-axis torque would be when the z-axis of your throwing motion doesn't match the z-axis of the spinning disc.

We're dealing with precession here which can be hard to visualize and understand. But if I understand it correctly the angle that you impart in the XY plane to spin the disc sets the orientation of the Z axis. In other words, if you tilt the XY plane then the Z axis stays perpendicular to the plane and it tilts away from vertical. So the Z axis of your throwing motion always equals the Z axis of the spinning disc. I think you meant to say that with OAT the Z axis you produce tilts away from vertical. When the Z axis is vertical then you've made a flat throw. When the Z axis is at any angle other than vertical then you've got OAT.

 

[Tree Seeking Device]

When the Z axis is vertical then you've made a flat throw. When the Z axis is at any angle other than vertical then you've got OAT.

Not quite. Anhyzer and hyzer are both created when the disc's z-axis is not vertical - but it is possible to throw both with no OAT.
I think the easiest way to distill it in terms of your coordinate system: OAT is any force vector applied to the rim of the disc that is not in the XY plane.

Might be easier to think in terms of cylindrical coordinates (r, theta, z) where the z-axis is perpendicular to the flight plane of the disc. A force in the radial direction accelerates the disc. A force in the angular direction (theta) imparts spin. Any force with a non-zero z component applied away from the center of the disc creates OAT.

Yes I'm a physics geek.
:roll:

 

[rehder]

I'm not sure if I understand the term OAT correctly. Could someone explain it,
really slowly, with pics 'n vids 'n shit. So, what is off axis torque, and what it
causes to a disc golf discs flight path?

holf your arm straight out in front of you like you where going to shake somebodys hand. Now roll your hand clockwise, so that the palm faces up, and the thumb sticks out to the right. Thats wrist roll. But it is only one way of inducing OAT.

It can be used well in throwing rollers, and to keep very understable discs from flipping, if you roll your wrist the other way.

The problem with it is, that is more of an advanced concept, that you should introduce once you have a solid grip on the throwing fundamentals.


What happens when newer players grab a disc that is speed overstable, is that they cant match the speed required to make it fly straight, to get it to fly straight they then introduce wrist roll to their throws, so what they do is throw s-line shots to get more distance out of the disc. Mind you they arent really throwing straight shots, they are flex-shots wich have more or less play in the left-to-right.

Now when said player has thrown a ton of these shots and wrist-roll has become ingrained in his throw, and he grabs a midrange or a putter, and the tries to throw it, it will divebomb to the right and as was said above turn into a cutroller, because these discs dont mask the OAT