Pinch/trap it between the clubface and the turf?

[Gibby]

I hear this description of compression constantly.

This is more of a conceptual thing, right? I mean, if this were literally happening, the ball would be compressing in two different places: the top and the bottom. When I watch a pro compress the ball in slow motion, the only point of compression occurs at the back of the ball.

The words "pinching" and "trapping" suggest that the force is being delivered down into the top of the ball, driving it down into the turf, and then the ball somehow rebounding off the ground into the air.

So although this seems to be an effective description of the intended feeling, it is not literally what happens. Right?

 

[JamesBurg]

Right.

 

[Kevin Shields]

I hear this description of compression constantly.

This is more of a conceptual thing, right? I mean, if this were literally happening, the ball would be compressing in two different places: the top and the bottom. When I watch a pro compress the ball in slow motion, the only point of compression occurs at the back of the ball.

The words "pinching" and "trapping" suggest that the force is being delivered down into the top of the ball, driving it down into the turf, and then the ball somehow rebounding off the ground into the air.

So although this seems to be an effective description of the intended feeling, it is not literally what happens. Right?

This Peter Kostis type description drives me absolutely effin crazy every time i hear it on TV. I dont know where it came from.

 

[Mashie72]

Something to Ponder

I'm not 100% sure...There might be a small resultant trapping force in terms of added/less resistance..If you take 3 lies, the sand, normal grass lie and hardpan, I would think you would hit the ball three slightly different distances.

Mashie 72

 

[Robbohank]

Seems like "pinch or trap" is still what's happening to some degree. Any good iron shot is going to be ball-first contact which indicates a slightly descending blow, and the turf is providing "some" resistance.

What would be a more accurate description that "the masses" would understand?

 

[Jim Kobylinski]

No, no, no.

The ball is GONE before the club is even taking a DIVOT if you hit it correctly. Its just a feel
not a real.

 

[JamesBurg]

You would have to have a club with negative loft to compress a ball, even slightly, against whatever it is lying on.

 

[Kevin Shields]

No, no, no.

The ball is GONE before the club is even taking a DIVOT if you hit it correctly. Its just a feel
not a real.

To concur, the ball in a good swing is long gone before any contact with the ground or tee on any surface. Just look at the swingvisions on you tube. Its as plain as day.

 

[Kevin Shields]

I'm not 100% sure...There might be a small resultant trapping force in terms of added/less resistance..If you take 3 lies, the sand, normal grass lie and hardpan, I would think you would hit the ball three slightly different distances.

Mashie 72

If you're not hitting it absolutely correct, you might get a flyer off the grass lie. Assuming no interference with the ball-face contact, all 3 lies should travel the same distance.

 

[Damon Lucas]

I think what happens a lot of the time with various lies is that people instinctively adjust the amount of forward lean and angle of attack to ensure good contact and that creates different trajectories and spin rates. Also the type of release might change, and combined you get some different spin rates.

 

[Mashie72]

Pool Anyone?

You would have to have a club with negative loft to compress a ball, even slightly, against whatever it is lying on.

What about the mechanics of a slight draw shot in pool? Contact is below the cue ball's equator with a slight decending angle of attack and the cue tip's contact is on top (positive loft)...

At impact the cue ball is compressed slightly against the cloth even though we have loft..

 

[Mashie72]

Could be..

If you're not hitting it absolutely correct, you might get a flyer off the grass lie. Assuming no interference with the ball-face contact, all 3 lies should travel the same distance.

IMO, the only way to know for sure is to test it out...bring some sand to the launch monitor or bring the launch monitor to the sand...There's no debate..It either is a factor or it isn't..

Mashie72

 

[dbl]

Mashie72, I think you are discounting what Damon posted.

"Facts" are not always what they seem. Even on a LM a golfer might adjust what he is doing.

 

[Mashie72]

I'm just curious

Mashie72, I think you are discounting what Damon posted.

"Facts" are not always what they seem. Even on a LM a golfer might adjust what he is doing.

I agree with you and Damon...In the real world under actual conditions we probabaly all make adjustments and get different results...I'm just curious if any testing has ever been done with a robot that keeps everything the same and measured the results of the three different conditions...

Mashie72

 

[dbl]

Oh...a robot on a LM....maybe it would show something (or nothing!).

 

[Jim Kobylinski]

You could "rig" the robot test too if you wanted; here's how:

Flyer lie:

You could choose how much of a flyer lie it really is based on the height of the grass and the lie of the ball

Sand lie:

You could choose very soft or very hard sand

Standard lie:

You could choose a decent public course mown fairway or augusta mown fairway

------------

Depending on how you setup the test would have varying results

 

[Mashie72]

Robot Test

Yes Jim...Maybe even throw in the 4th lie of hardpan (very short dead bent/links grass) where the ball is truly on the ground

 

[pecky987]

forgive my very basic knowledge, but if the clubhead force is travelling downward when it hits the ball, then surely there is some force on the ball downward into the ground

 

[Jim Kobylinski]

forgive my very basic knowledge, but if the clubhead force is travelling downward when it hits the ball, then surely there is some force on the ball downward into the ground

I'm not physics expert at all, AT ALL, but my logical brain says that it is heavily minizmied by LOFT. Thus that's why it's easier to get higher lofted clubs out of the rough easier because the ball is going more "up" than it is going "forward" thus reducing the resistance of the rough.

Just my "hunch" and not rooted in any science

Hopefully that is enough disclaimers lol

 

[Gibby]

"forgive my very basic knowledge, but if the clubhead force is travelling downward when it hits the ball, then surely there is some force on the ball downward into the ground"

------->
http://www.youtube.com/watch?v=4MlhxXKTjMg

Please observe impact at 0:51 seconds several times. Where is the point of compression? Does the ball deflect in any way off the ground? Does it deflect off the tee?

After viewing as many super slow motion impact videos as I could find, I have concluded that the point of compression ALWAYS occurs directly on or below the equator of the ball.

Amazingly, even after seeing this clear picture of compression, the announcer still continues to repeat the flawed "pinching" analogy.