Snap vs. Hit

[BogeyNoMore]

Originally Posted by rocthecourse

Correct me if I am wrong but they are sort of the same(at least some of the time.) OAT is bad form causing some of that torque(snap) to be off the plane(axis.)

Or to put it another way. snap=good torque, OAT=bad torque.

But then again not all OAT is the same.

I don't know, just a thought.

I think you're getting it, but are having some difficult experessing it.
The difference between the two torques you mention is the axis about which they are acting.

Once you let go, the axis the disc rotates about it's center of mass. But prior to letting go, the axis the disc is rotating about at the edge of the disc (specifically the point at which you are holding it). The part of the disc furthest from your hand is moving faster than the part in your hand, which imparts the spin when you let go - because it can no longer rotate about a pivot that no longer exists. The greater that differential is (i.e. the faster you accelerate the disc through the snap) the more spin is imparted to the disc.

OAT is simply rotation about a different axis, caused by "rolling" your wrist as you throw.

Trying to describe them two dimensionally, to see the first axis, you would look downn on the disc as it's being thrown. Standing directly overhead, looking down at the point where the disc is being held - that line of sight would be the axis.

Standing behind a person throwing (RHBH to illustrate), looking toward the fairway: as they are releasing the disc, if they rotate their wrist with a palm up motion (even if it they don't rotate nearly until their palm is truly facing up) rotates the disc from the plane of motion it was pulled through prior to the release. The axis of rotation isn't through the disc - it's through your wrist as you rotate (or twist) the disc out of the plane you started it on. The axis of rotation changes pepedning on wher your arm is in yout motion, but basically, along your forearm.

I believe it's called it "Off Axis" because its a torque that isn't on the axis you want it to act on (i.e. the pivot point whereyou hold the disc). That's the axis you where you want to apply torque - because it will propel the outer edge of the disc fwd, inducing spin.

Torqing the disc about your forearm is undesireable because it induces a change in the angle the disc is released at, and if severe, can cause the disc to 'turn and burn' - This commonly happens when really trying to muscle a disc.

I hope that helps.

[BogeyNoMore]

Originally Posted by mashnut

Torque is a force which produces rotation, you don't have a spinning disc without applying torque. What you want is torque applied on the plane of your throw, when you apply torque in a different plane you pull the rotation off it's axis.

I wish I could explain with Masnut's economy of words.

[Lewis]

Originally Posted by jrawk

Here's the diagram:

I think you should tell us what all the shapes and lines are in the diagram. I don't see a person, an elbow, a wrist, or a hand, and I'm not sure where the disc is, or what the direction of the throw is.

[Dan Ensor]

Purple thingy's the hand, green thingy's the disc.

[BogeyNoMore]

^ hmm, never thought of it that way, that makes sense. Now I understand it perfectly!
Anyone care to explain what we're looking at, or is that some sort of art nouveau?

[Dan Ensor]

http://www.discgolfreview.com/forums...24903&start=30

[mashnut]

Originally Posted by jrawk

yes torque is a force, but torque is being discussed in this thread as power/muscle. Which it shouldn't be. More power does not create more spin. Maximizing the rotational force is not achieved through power torquing.

Torque is a word that means a specific thing. Whatever you think it refers to, it still means a force which causes rotation. In disc golf, torque is a good thing if you can apply in on the same axis as your throw. You're trying to apply other definitions to that word.

[theeterrbear]

Sigh, torque is a force about an axis. Plain and simple. When you use a wrench on a bolt, the rotation of the wrench about the bolt (the axis) is a result of torque. Torque is defined as tau = rFsin(theta), where tau is torque, r is the displacement, F is the scalar of the force, and theta is the angle of the applied force. In the wrench, it's why when you push perpendicular (90*) on the wrench you get maximized torque for your distance (sin90*=1), and the farther out your hand is on the wrench the easier it is to rotate the wrench (r gets larger).

On a disc at the end of the hit is when the hand is torquing the disc. Also worth noting is that for our intents and purposes, r is constant. The disc is pinched between the rip finger and the thumb (pad) and from our frame of reference is rotating around this point. From the disc's inertial frame of reference, the rip point is applying a force back toward the body, and this results in the torque that gives the disc its spin.

I hope this helps, but I've been watching Suits and typing this in the commercials so there may be an error or two. This is just meant to help give a fundamental understanding of the forces at work. It'll take some more time and some reacquainting to work it out more. I strongly recommend checking out the thread that Dan Ensor linked to (and thank you for that) especially the first page.

[theeterrbear]

Originally Posted by Dan Ensor

Purple thingy's the hand, green thingy's the disc.

I wish I had noticed that earlier. I just want to point out now that the due to the disc's momentum being roughly linearly forwards and the hand being at 3 o'clock on the disc maximizes the amount of torque on the disc, as the force vector (from the disc's frame of reference) is now perpendicular to the edge of the disc (like a tangent) which creates the 90* angle needed to achieve sin(theta)=1, r from earlier is constant (in our model), which means that the force applied is dependent on the speed of the disc.

I'm doing this on the fly, and sorry for having two posts in a row.

[garublador]

Originally Posted by jrawk

Snap is the worse term in disc golf terminology to ever catch on. It's nothing more than lingo that people define in different ways.

That's what it is now, but my understanding is that originally "snap" was defined as the difference between those throwing Teebirds 350' and 450'. Not nearly as much was really understood about what went into "snap" so a single, generic term was used. Now there are many more terms that are more descriptive and specific and people use "snap" to mean a bunch of different things, many of which have nothing to do with the original definition.

I like to describe OAT in aviation terms roll, pitch and yaw. Yaw is "on-axis" torque, and also what we call "spin." Pitch is nose angle and we rarely talk about this type of OAT, but it does exist. Roll is the "off-axis" we're normally talking about.