"OAT"

[natedg1976]

Wow. I think the op needs to step away from the computer and go throw a round. I know I am after reading this. By the way I understand and agree with what you are saying, but also think being smug and condescending is not the way to go about getting your point across. Lighten up Doof.

 

[Doofenshmirtz]

haha....I started the exact same thread with the same questions/purpose about a year ago: OAT is a stupid concept

Yep, and the discussion was about wobble until Post #15, when somebody goes off track a little.

 

[Pwingles]

Well if we are gonna have the equivelant to the "stable means straight, not overstable" discussion, we may as well try and be civil.

This thread and theory is intriguing to me, so lets keep at it.

 

[Doofenshmirtz]

Now that the bell cow is blushing, and the herd is attentive, what's next?

I wish I had the answer. I suspect that a year from now, people will still be misusing "OAT" in the same way.

 

[Pwingles]

I wish I had the answer. I suspect that a year from now, people will still be misusing "OAT" in the same way.

At what point does banging your head against the wall over and over again to explain that a phrase's accepted definition and literal definition arent the same, become worth it tho

Question 2, what happens when they acknowledge the incorrect usage and keep using it

 

[Doofenshmirtz]

At what point does banging your head against the wall over and over again to explain that a phrase's accepted definition and literal definition arent the same, become worth it tho

Question 2, what happens when they acknowledge the incorrect usage and keep using it

No banging here. As to question 2: I suspect people will avoid that and will not want to knowingly use the word improperly. But then some people keep saying "chih poll tay" even when the correct pronunciation is pointed out to them.

And, seriously, most people aren't going to read this thread anyway.

 

[Pwingles]

I would argue your answer to question 2 is wrong based on how many people knowingly use 'stable' as a descriptive term, to describe something that has a different meaning.

Similar to when people say 'cool' and what they really mean is, 'thats ok' or 'thats acceptable to me' or any other variation of a similar phrase. We all mnow you dont mean the temperature of what you said is literally cold, but the shorthand has been adopted into our lexicon anyway, despite its literal incorrectness, it has evolved to mean something else. Language and words have that luxory, physics (which, i am nowhere near an expert, obv), not so much.

 

[Doofenshmirtz]

I would argue your answer to question 2 is wrong based on how many people knowingly use 'stable' as a descriptive term, to describe something that has a different meaning.

Similar to when people say 'cool' and what they really mean is, 'thats ok' or 'thats acceptable to me' or any other variation of a similar phrase. We all mnow you dont mean the temperature of what you said is literally cold, but the shorthand has been adopted into our lexicon anyway, despite its literal incorrectness, it has evolved to mean something else. Language and words have that luxory, physics (which, i am nowhere near an expert, obv), not so much.

I guess with "stable," there is a semantic difference. "Over" and "under" as prefixes to "stable" at the very least suggest that "over" = too much or "more" stability and "under" = too little or "less." Those words, irrespective of meanings as terms of art, appear to describe different levels of "stability" and, at the very least, most people probably know what someone means when they say "more stable" or "less stable" even if the listener/reader thinks the speaker/writer is using the terms incorrectly. "OAT," on the other hand, is being blamed for something it doesn't cause. You may be right about people continuing to use it even if they suspect they are using it incorrectly, hence my Chipotle reference. I am also not silly enough to think that people will read this whole thread and suddenly agree with me. Then again, maybe someone will post a video of a disc rotating around two axes at once and I'll have to eat my words.

 

[Olorin]

I haven't read this entire thread very closely, mainly because what I have read does not impress me much. I have a background in engineering and I have rather seriously studied the aeronautics of frisbee flight for several years. These long intricate discussions never seem to make sense based on what I know of aeronautics. The flight of a frisbee is so amazingly complex that what I have read on DGCR over the years always seems lacking and containing a great deal of misinformation.

Bottom line: Why can't OAT just be called "wobble"? Wobble is so much easier to understand and to visualize.

 

[garublador]

Then again, maybe someone will post a video of a disc rotating around two axes at once and I'll have to eat my words.

You're getting hung up on how we define our axis.

Imagine attaching a 6-degree of freedom inertial measurement unit mounted parallel to the flight plate and perfectly rigid (it won't move with respect to the flight plate). Now imagine someone throws the disc in a way that makes it flutter. What would the output of the rotational sensors show? If the disc can only rotate about one axis, which single axis will the sensor show as having torque?

If prefer you can think of OAT as meaning "throwing about an axis other than the one perpendicular to the flight plate." That way you don't have to imagine multiple axes. Though it's exactly the same as what I've been describing.

 

[garublador]

Bottom line: Why can't OAT just be called "wobble"? Wobble is so much easier to understand and to visualize.

A couple reasons.

First, you don't always see the wobble and the disc wobbling isn't really the problem. The problem many times is that the disc turns over too much.

Second, what do you say when someone asks what causes "wobble?" Using your definitions "wobble" causes "wobble" and that's not a terribly useful explanation.

 

[Aim For The Chains]

Rotation around a fixed axis is a special case of rotational motion. The fixed axis hypothesis excludes the possibility of an axis changing its orientation, and cannot describe such phenomena as wobbling or precession. According to Euler's rotation theorem, simultaneous rotation along a number of stationary axes at the same time is impossible. If two rotations are forced at the same time, a new axis of rotation will appear.

--assumes that the rotation is also stable, such that no torque is required to keep it going. The kinematics and dynamics of rotation around a fixed axis of a rigid body are mathematically much simpler than those for free rotation of a rigid body; they are entirely analogous to those of linear motion along a single fixed direction, which is not true for free rotation of a rigid body. The expressions for the kinetic energy of the object, and for the forces on the parts of the object, are also simpler for rotation around a fixed axis, than for general rotational motion. For these reasons, rotation around a fixed axis is typically taught in introductory physics courses after students have mastered linear motion; the full generality of rotational motion is not usually taught in introductory physics classes.

http://www.writeopinions.com/rotation-around-a-fixed-axis

garublador: +1

a disc doesn't float in the air b/c you spin it lol. Pretty easy Doofman'

 

[Doofenshmirtz]

http://www.writeopinions.com/rotation-around-a-fixed-axis

garublador: +1

a disc doesn't float in the air b/c you spin it lol. Pretty easy Doofman'

It doesn't "float" at all. But it also would not fly like it does if you didn't spin it. That this or your quote has nothing to do with the misuse of the word OAT appears to be beyond your grasp.

 

[rocthecourse]

It doesn't "float" at all. But it also would not fly like it does if you didn't spin it. That this or your quote has nothing to do with the misuse of the word OAT appears to be beyond your grasp.

What is the proper use of the word OAT?

 

[BogeyNoMore]

I haven't read this entire thread very closely, mainly because what I have read does not impress me much. I have a background in engineering and I have rather seriously studied the aeronautics of frisbee flight for several years. These long intricate discussions never seem to make sense based on what I know of aeronautics. The flight of a frisbee is so amazingly complex that what I have read on DGCR over the years always seems lacking and containing a great deal of misinformation.

Miss Information really gets around... she's quite a popular gal.

 

[ejvogie]

The last name of an idiot villain from a kid's cartoon? Yep, perfect name for a troll account.




<----leaves now while this invaluable information sinks in

 

[Hampstead]

From what I have experienced, there are generally three types of people who actually use the term OAT in reference to disc golf.

1. Those who spend way too much time analyzing and over-analyzing the game and all of its minutiae

2. Those who blame every bad throw on OAT

3. Those who hear someone blame a bad throw on OAT and say "What in the world is OAT?"

 

[str8]

What is the proper use of the word OAT?

I got really torqued last night, so I wobbled downstairs and had some OAT cereal and a cinnamon roll. Does anybody know where my ax is?

 

[Doofenshmirtz]

You're getting hung up on how we define our axis.

Are you now still insisting that you can exert rotational inertia on the roll axis that causes the disc to roll right after release while it is simultaneously spinning on the yaw axis?

That is what you were claiming.

As to what a sensor would show, why don't you put it on a disc and tell us. Speculating about its readings is like arguing over math.

Better yet, please post that video of the disc freely spinning about two axes. If the cause of a roll to the right is the "OAT" induced roll momentum that you describe, you should have zero problem demonstrating that by just tossing a disc up in the air and giving it an "off axis" push on release.

As to getting hung up on "how we define our axes," I've ignored those comments until now because they are simply unhelpful. An object moving in a striaight line through three dimensional space can be described by the changing of three coordinate values. That does not mean that it is traveling in three directions at once. And while axes can be "imaginary" as you put it, the spin axis is determinable. Irrespective of what "off" axis to which you apply torque on release and how you want to define that axis, there will be only one spin axis after release, whether the disc wobbles or not. More "off axis torque" will result in a bigger wobble, not a seemingly smooth spinning or slightly wobbling disc that rolls to the right due to inertia acting on the roll axis.

 

[garublador]

Heinz. Can I call you Heinz?

Doofenshmirtz,

I know it hasn't been very long, but any thoughts on my inertial sensor question?

Here's another one. We will define the x/y plane as the plane the disc sits on. The z axis always goes straight up through the flight plate and we'll call it the "on" axis. The torque vector for any throw can be represented as (x,y,z). For a clean throw, x and y are zero (or probably just minimized in real life). For a wobbly throw, x and/or y are significant. There are components on either or both of the "off" axes. Or, you can say the axis of rotation is "off" the z axis. Either way, there is torque in a direction that isn't directly along the z axis.

I have no problems admitting that I probably don't use the word "component" or the phrase "direction of" as much as would be perfectly correct, but getting too bogged down in semantics in this context would make the advice harder to read and less useful. Remember this is a disc golf forum and most of the discussion has to do with improving technique. In a physics thread it makes more sense to pay closer attention to how everything is stated. Context is key.