Understability Really Two Things?

[HyzerUniBomber]

Dude, you need to look 'torque' up in the dictionary 'cause you're using it wrong. It doesn't mean what you think it does. I'd also recommend working on your reading comprehension as you respond to things that weren't actually said.

https://www.youtube.com/watch?v=N92FYHHT1qM&feature=youtu.be&t=2749

Torque along the axis of the spinning gyroscope. Walter Lewin of MIT explains.

 

[TheBeardedFatGuy]

https://www.youtube.com/watch?v=N92FYHHT1qM&feature=youtu.be&t=2749

Torque along the axis of the spinning gyroscope. Walter Lewin of MIT explains.

Dictionary.com. Torque. Actual definition, not someone talking about it.

 

[HyzerUniBomber]

Dictionary.com. Torque. Actual definition, not someone talking about it.

In physics, there are two types of precession: torque-free and torque-induced.

https://en.wikipedia.org/wiki/Precession

Dictionary.com isn't going to explain physics.

 

[TheBeardedFatGuy]

In physics, there are two types of precession: torque-free and torque-induced.

https://en.wikipedia.org/wiki/Precession

Dictionary.com isn't going to explain physics.

Nooo it explains what a word actually means. Never said a thing about trying to explain physics. I just maintain the use of the word was wrong based on its definition. And it was used incorrectly.

 

[sidewinder22]

Dude, you need to look 'torque' up in the dictionary 'cause you're using it wrong. It doesn't mean what you think it does. I'd also recommend working on your reading comprehension as you respond to things that weren't actually said.

I think you are in need of comprehension.

Let's break your post down...

Airspeed is a measurement of air speed. It doesn't torque anything. That's like saying cheetah speed eats gazelles. Also, torque promotes rotation, it doesn't inhibit it, and I don't see how air anything promotes rotation, unless you're talking pinwheels. Air 'resistance', for example, can act against the torque already present, but I don't see how it can promote it.

Airspeed is not just a measurement, it's the actual air molecules/matter flowing in a direction relative to the object, in our case a flying disc. This air flow is what causes the disc to lift. If there is no airflow, there is no lift. Lift is torque 90 degrees from the air flow that causes the disc to flip/rotate end over end if it is not spinning. However when we throw, the disc is spinning and therefore resists flipping/rotating end over end due to gyroscopic properties.

I still have no clue what your cheetah speed eats gazelles is talking about. Are you talking about the discs or the animals? Not that it probably even matters.

My two cents on wobble is that it causes diametrically opposite points on a disc's rim (highest and lowest) to alternately turn into and then away from the onrushing air as the disc moves through it. The result is air brake up, air brake down, air brake up, air brake down. And that's not even taking into account the disastrous airfoil this makes during all degrees of wobbled rotation. All told, the effect is to slow or stall the forward progression. It can't help but slow rotation, too, I suppose - friction is friction.

Friction is friction. If friction is slowing the spin, it's also then slowing or stalling the forward momentum. I'd say friction slows the forward momentum faster than the spin though.

If there's any validity at all to wobble contributing to left or right movement it would be because the resistance caused by the high and low points is greater on the left (RHBH) because they're rotating into the wind, than on the right because they're rotating away from the wind.

A disc can wobble in two directions regardless of spin direction.

Unless you can make a case for deflection in addition to drag, the effect must be to turn the disc to the left (again, RHBH) because, like a tank with a bad tread, resistance pulls a moving object in the direction towards the side with greater drag. Same thing if you try to walk a straight line dragging a cinder block tied to your left ankle - it'll turn you to the left.

Friction does not cause you to rotate. Moving forward on two different axis causes you to rotate. Normal walking forward (without cinder block) causes you to rotate as your axis changes right to left to move yourself forward. If your pelvis ain't rotating as you walk or run I'd like to see it. If you are rotating friction will anti-rotate you. The actual torque/power/force is generated by the axis, not the cinder block dragging. The cinder block resists your pelvis from actually rotating which is why you will walk in a circle if you don't adjust for the difference in torque/force required. A tank with a bad tread has two different axis conditions which causes rotation.

 

[HyzerUniBomber]

Nooo it explains what a word actually means. Never said a thing about trying to explain physics. I just maintain the use of the word was wrong based on its definition. And it was used incorrectly.

In the world of physics, like the MIT professor and the linked Wikipedia article, specific to this conversation - we are talking about the torque (adding weight in the video) on the axis of a spinning disc.

If you want to take issue with the world using torque to describe that - then have at it - as you seem to be saying that Wikipedia and MIT professors have it wrong?

 

[sidewinder22]

but Sidewinder will just insist a disc spins at the same velocity from start of flight to end. He's wrong, but he will insist.

I never said it doesn't slow spinning in flight, just doesn't slow spin nearly as fast as it's forward momentum.

Friction is friction. If friction is slowing the spin, it's also then slowing or stalling the forward momentum. I'd say friction slows the forward momentum faster than the spin though.

The only time that spin and forward momentum are slowed at the same rate by friction is with rollers. Sometimes you will see a disc peeling out when it first lands on a roller because it's spinning faster than it's forward speed. I've sometimes seen the disc pick up speed after landing, it's like walking the dog with a yo-yo. Rollers tend to go longer than air shots, because the spin will keep going longer than it's forward momentum would have. And I have to image there is a lot more friction rolling on the ground than flying in the air, as it has two sources of friction rolling - the air and ground.

 

[TheBeardedFatGuy]

I think you are in need of comprehension.
Airspeed is not just a measurement, it's the actual air molecules/matter flowing in a direction relative to the object, in our case a flying disc.

No it isn't. Dictionary, man. For God's sake. Words have actual defined meanings. Airspeed is most definitely NOT the air, it is a MEASUREMENT of the movement of the air. Using it in any other way is simply wrong.

Lift is torque 90 degrees from the air flow that causes the disc to flip/rotate end over end if it is not spinning.

Lift is NOT torque. I suppose lift, depending where it is centered, can CAUSE torque, but it is not torque.

I still have no clue what your cheetah speed eats gazelles is talking about. Are you talking about the discs or the animals? Not that it probably even matters.

I'll 'splain. You said, "..the airspeed torques it." As I've pointed out, airspeed is a measurement, like the speed of a running cheetah is a measurement. Saying airspeed torques anything is like saying a measurement of the cheetah's speed does something the cheetah is actually doing (i.e. eating gazelles). If you don't get analogies, avoid the SAT like the plague. It's speed might flunk you. Okay, that was mean. Sorry.

Friction is friction. If friction is slowing the spin, it's also then slowing or stalling the forward momentum. I'd say friction slows the forward momentum faster than the spin though.

I don't disagree with this. In fact, you make several statements in response to my comments that I don't have any disagreement with, though I'm a bit confused why you're saying them at all as they have nothing to do with anything I've said.

Case in point:

A disc can wobble in two directions regardless of spin direction.

You might as well be saying, "Cheese is a dairy product." It's true, but irrelevant to anything I've said so not sure why you're saying it.

Friction does not cause you to rotate. Moving forward on two different axis causes you to rotate. Normal walking forward (without cinder block) causes you to rotate as your axis changes right to left to move yourself forward. If your pelvis ain't rotating as you walk or run I'd like to see it. If you are rotating friction will anti-rotate you. The actual torque/power/force is generated by the axis, not the cinder block dragging. The cinder block resists your pelvis from actually rotating which is why you will walk in a circle if you don't adjust for the difference in torque/force required. A tank with a bad tread has two different axis conditions which causes rotation.

No, friction applied unevenly, more to one side of a forward moving object than the other, will tend to cause it to turn towards the greater point of resistance to forward movement. The only exception is when friction takes the form of deflection, but that's a whole 'nother discussion. Like the tank and cinder block analogies I used, the greater friction/drag caused to one side slows that side. As the non-hindered side continues forward the effect is to turn towards the slower side. Another analogy would be throwing an anchor out on the left side of a forward moving boat. Once it catches, the boat will swing to the left.

I've had my say. I'm out.

 

[sidewinder22]

No it isn't. Dictionary, man. For God's sake. Words have actual defined meanings. Airspeed is most definitely NOT the air, it is a MEASUREMENT of the movement of the air. Using it in any other way is simply wrong.

"Airspeed is the speed of an aircraft relative to the air." https://en.wikipedia.org/wiki/Airspeed
It is not a measurement of the movement of air, it's the speed of the object relative to the air.

Increasing airspeed = increasing airflow = increasing lift = increasing torque.

Lift is NOT torque. I suppose lift, depending where it is centered, can CAUSE torque, but it is not torque.

How can something cause torque, but not be torque? An airplane wing's lift torque is typically counter balanced by the tail. A plane without a tail is typically not very stable and likely to flip even with an asymmetrical wing design to help balance the plane. Plane wing designs are typically quite asymmetrical unlike a symmetrical disc. A disc has no tail or asymmetrical design to aerodynamically counter that torque, so instead we spin the disc to counter balance it gyroscopically.

The only way lift might not be considered torque on a disc is if it wasn't moving forward, only then might the lift be equal or balanced so to not cause rotation, but the problem with that is a disc would be falling and parachute dragging and not generating positive altitude lift force(unless there is some updraft, even then that updraft would have to be perfectly upward to not cause a torque rotation). Drag is not lift.

I'll 'splain. You said, "..the airspeed torques it." As I've pointed out, airspeed is a measurement, like the speed of a running cheetah is a measurement. Saying airspeed torques anything is like saying a measurement of the cheetah's speed does something the cheetah is actually doing (i.e. eating gazelles). If you don't get analogies, avoid the SAT like the plague. It's speed might flunk you. Okay, that was mean. Sorry.

Well if you are the person writing the analogies for the SAT, nobody would pass. I guess I didn't flunk the SAT's though when I took them 20 years ago, at least my math score was almost perfect.

I don't disagree with this. In fact, you make several statements in response to my comments that I don't have any disagreement with, though I'm a bit confused why you're saying them at all as they have nothing to do with anything I've said....

Right, I didn't disagree, I made a further clarifying statement. Why is that hard to comprehend?

You might as well be saying, "Cheese is a dairy product." It's true, but irrelevant to anything I've said so not sure why you're saying it.

...You only mention one direction of wobble when you said...

because the resistance caused by the high and low points is greater on the left (RHBH) because they're rotating into the wind, than on the right because they're rotating away from the wind.

...And you should have used the term airspeed or airflow instead of wind, unless you are actually talking about wind, but you did not indicate what direction the wind is blowing and would be assuming the wind is somehow always the same direction relative to the disc's direction.

No, friction applied unevenly, more to one side of a forward moving object than the other, will tend to cause it to turn towards the greater point of resistance to forward movement. The only exception is when friction takes the form of deflection, but that's a whole 'nother discussion. Like the tank and cinder block analogies I used, the greater friction/drag caused to one side slows that side. As the non-hindered side continues forward the effect is to turn towards the slower side. Another analogy would be throwing an anchor out on the left side of a forward moving boat. Once it catches, the boat will swing to the left.

Friction is not torque, nor is tension torque. You are unbalancing two separate axis on your two axis vehicle, and continuing to generate equal force to those two unbalanced axis. The vehicle is going to orbit on a path outside its axis with the same attitude, but not rotate on it's own axis.

Your off axis boat anchor is going to change the effective bow and cause the boat to orbit to the anchor with the same bow attitude until it settles(which wouldn't take long in the water), the tension of the chain keeps the boat from rotating on it's own axis like a ball on a string doesn't spin or rotate on it's own axis. The boat is orbiting around the anchor, it's not rotating or twisting on it's own axis. Torque causes an object to rotate about it's own axis. The anchor is not an axis of the boat. Then tension of the chain between the anchor and boat creates centripetal force, not torque.

I've had my say. I'm out.

The village must have been worried about their special guy while he was gone.

 

[Atvizory2000]

I love reading posts after TheFatBeardedGuy has responded. Good Times opcorn:

 

[TheBeardedFatGuy]

"Airspeed is the speed of an aircraft relative to the air." https://en.wikipedia.org/wiki/Airspeed
It is not a measurement of the movement of air, it's the speed of the object relative to the air.

Tell you what, why don't you tell me what the airspeed of your next drive is. Oh, wait, to do that you'd have to MEASURE it. Any speed is expressed as a measurement on some scale, like 35 mph.

Increasing airspeed = increasing airflow = increasing lift = increasing torque.

Wrong. What you have there is a string of causes and effects, not of equal elements.

How can something cause torque, but not be torque?

I don't know. How can a car cause movement but not be movement? Yet, somehow, it manages to not be movement.

The only way lift might not be considered torque on a disc is if it wasn't moving forward, only then might the lift be equal or balanced so to not cause rotation, but the problem with that is a disc would be falling and parachute dragging and not generating positive altitude lift force(unless there is some updraft, even then that updraft would have to be perfectly upward to not cause a torque rotation). Drag is not lift.

Okay. Never said drag was lift, so not sure your point there. And you're first sentence there is wrong in a couple ways. I would never consider lift to be torque - it might CAUSE torque (torsion or rotation) if the center of lift is not the same point as the center of mass. In other words, it is a force pulling a disc that wants to rotate around its center of mass, so it torques the disc. If the center of lift is forward of the center of mass, the effect is to rotate or pitch the nose of the disc up.[/QUOTE]

Right, I didn't disagree, I made a further clarifying statement. Why is that hard to comprehend?

To me, when you're arguing, you respond to or counter the other person's statements. When you throw other stuff in, it's confusing because it isn't something that was discussed.

...You only mention one direction of wobble when you said...

...And you should have used the term airspeed or airflow instead of wind, unless you are actually talking about wind, but you did not indicate what direction the wind is blowing and would be assuming the wind is somehow always the same direction relative to the disc's direction.

Because what I was referencing only dealt with one direction of wobble. Why would I complicate it?

Friction is not torque, nor is tension torque.

Never said it was, so not sure of your point.

Your off axis boat anchor is going to change the effective bow and cause the boat to orbit to the anchor with the same bow attitude until it settles(which wouldn't take long in the water), the tension of the chain keeps the boat from rotating on it's own axis like a ball on a string doesn't spin or rotate on it's own axis. The boat is orbiting around the anchor, it's not rotating or twisting on it's own axis. Torque causes an object to rotate about it's own axis. The anchor is not an axis of the boat. Then tension of the chain between the anchor and boat creates centripetal force, not torque.

Torque is "something that produces or tends to produce torsion or rotation" all of the left side analogies I've used do this.

The village must have been worried about their special guy while he was gone.

[/QUOTE]

The lowest form of debate is to shift from attacking a statement or position and instead lob insults at one's opponent. Congratulations, man. You must be proud.

 

[sidewinder22]

Tell you what, why don't you tell me what the airspeed of your next drive is. Oh, wait, to do that you'd have to MEASURE it. Any speed is expressed as a measurement on some scale, like 35 mph.

You can bring your calculator and throw your disc on paper. I'm going to throw a disc in the real physical world where the air exists.

Wrong. What you have there is a string of causes and effects, not of equal elements.

They are all directly related. You even said yourself that lift can cause rotation, torque is the cause of rotation, rotation is the effect.

I don't know. How can a car cause movement but not be movement? Yet, somehow, it manages to not be movement.

You answer my question about your statement with a question that makes no sense.

Okay. Never said drag was lift, so not sure your point there. And you're first sentence there is wrong in a couple ways. I would never consider lift to be torque - it might CAUSE torque (torsion or rotation) if the center of lift is not the same point as the center of mass. In other words, it is a force pulling a disc that wants to rotate around its center of mass, so it torques the disc. If the center of lift is forward of the center of mass, the effect is to rotate or pitch the nose of the disc up.

Causation without representation?

To me, when you're arguing, you respond to or counter the other person's statements. When you throw other stuff in, it's confusing because it isn't something that was discussed.

That's what reading comprehension is for.

Because what I was referencing only dealt with one direction of wobble. Why would I complicate it?

Why would you only halfway explain something?

Never said it was, so not sure of your point.

You sure did imply friction is torque because you say friction/drag is causing rotation.

The lowest form of debate is to shift from attacking a statement or position and instead lob insults at one's opponent. Congratulations, man. You must be proud.

Pot meet kettle...

If you don't get analogies, avoid the SAT like the plague. It's speed might flunk you. Okay, that was mean. Sorry.

 

[DG_player]

A disc can wobble in two directions regardless of spin direction.

I think we need a little clarification on wobble. A disc always wobbles in one direction.

The axis of spin will always point in the same direction (absent outside torques). The wobble axis or rotational axis will precess in a circular motion around this spin axis, in the direction of the spin. It will also do this at a very specific rate, at 1/2 the rate of spin.

With no outside forces this would continue on forever, however the aerodynamic forces quickly dampen it with a disc. Throughout the wobble phase of flight the disc is going to be alternating between a nose up attitude and nose down attitude.

 

[DG_player]

How can something cause torque, but not be torque?

Torque is just a directional force. If the lift is centered directly below the center of mass, it is not creating any torque, it's simply pushing the disc up. If it's off center it's pushing the disc up AND creating a rotational force.

 

[vdWcontact]

this escalated quickly...

 

[TheBeardedFatGuy]

You can bring your calculator and throw your disc on paper.

You win, man. I can't stand to watch you flail any longer, getting pretty sad. I'm out for real this time.

 

[Dan Ensor]

TBFG should probably look up the definition of "measurement". It's a representation of a physical phenomenon. A cheetah's speed does, quite literally and directly, catch him up to the gazelle so he can eat it.

 

[roggenb3]

I wish I was a cheetah. Especially one eating a Gazelle. Probably super lean and delicious.

 

[sidewinder22]

I think we need a little clarification on wobble. A disc always wobbles in one direction.

The axis of spin will always point in the same direction (absent outside torques). The wobble axis or rotational axis will precess in a circular motion around this spin axis, in the direction of the spin. It will also do this at a very specific rate, at 1/2 the rate of spin.

With no outside forces this would continue on forever, however the aerodynamic forces quickly dampen it with a disc. Throughout the wobble phase of flight the disc is going to be alternating between a nose up attitude and nose down attitude.

You sure about that? I think that would be like saying the disc only precesses in the direction of spin. I thought the disc wobbles in the direction of precession, not spin. This why rolling your wrist under causes the disc to wobble around more nose up, and rolling your wrist over causes the disc to wobble around more nose down. The different angle of wrist roll at release causes the wobble to start one direction or the other as the angle of the disc into the airflow will start different wobble rotation like it does with precession.

 

[sidewinder22]

Torque is just a directional force. If the lift is centered directly below the center of mass, it is not creating any torque, it's simply pushing the disc up. If it's off center it's pushing the disc up AND creating a rotational force.

In the context of throwing a disc, lift is only going to push the whole disc up if it is spinning(resisting torque). Otherwise if the disc is not spinning lift will torque and flip the disc over.

The only way lift might not be considered torque on a disc is if it wasn't moving forward, only then might the lift be equal or balanced so to not cause rotation, but the problem with that is a disc would be falling and parachute dragging and not generating positive altitude lift force(unless there is some updraft, even then that updraft would have to be perfectly upward to not cause a torque rotation). Drag is not lift.