How-To "Backspin on chips"

hi Mox
think of what Tiger said in your text.
the last part says,
which will result in a divot on the forward side of the ball.

that must mean the club hits the ball before the ground if the divot starts after the ball. so how if swinging shallower do you get this pinching of the club and ground. what really happens and what players think happen is not always the same, even if you tiger.
cheers
bill

Mox,

Tiger is wrong here and so are you or anyone that believes the ball can be trapped between the clubface and turf in the swing. Just try something that Bill suggested earlier: Place a ball on a table then take a club, say a 7 iron and lay it behind the ball, now see if you can trap the ball between the surface and clubface, you will see that the shaft will need to lean forward past horizontal to do it.

You should read the link I posted earlier in this thread it shows and explains to you how the ball reacts to the clubface. The ball is in contact for half a millisecond as it is struck an oblique blow by the loft(not a downward vector), it is compressed onto the clubface, slides up then rolls before the coefficient of restitution springs it off.

Look again carefully at these videos: Does the driver trap the ball in the turf? does the iron? No! of course they don't but they all create backspin.


Tiger may be a great golfer but he does not necessarily understand the ballistics or physics of impact.

Mox, you are a knowledgeable golfer but please give this matter some closer observation and you will see that 'pinching the ball' is a myth and impossible.

__________________
Best Regards
Brian

________________________________
Funny o'l game!

Of course they create backspin, but not a lot of backspin.

When hitting driver, you're actually hitting UP on the ball trying to AVOID backspin to gain distance.

And iron off the tee - struck on a downward trajectory - WILL 'trap' the ball between club and tee and generate more backspin.

A really great iron strike off the tee, will hammer the tee into the ground instead of chopping it in half like in your video.

You can choose to believe what you want. It matters little to me. But SIMPLE physics prove you wrong.

It seems to me, that you think 'trapping' or 'pinching' the ball is about thumping it into the ground, as in generating an angle between clubface and turf of less than 90 degrees. It is not! That is irrellevant. It is about the FACT, that during the very first part of that split-second contact between clubface and ball, there ARE force vectors working on the ball, that is going marginally into the ground resulting in friction between the ball and the ground as it starts to move. The resulting force back on the ball from the ground (or tee) is the 'trapping' or 'pinching'.

Your video actually proves my point, Brian. If you look at the driver shot and go frame-by-frame, you'll see that there is a point after the driver has hit the ball bug before the driver has hit the tee, where the trailing edge of the tee is actually already deforming from the friction between ball and tee. (freeze frame provided)

There is NO WAY that rubber tee would 'lip out' like that, unless there is pressure on it from the ball. And that is a sweeping strike. Imagine that being a downward trajectory! Oh yes - there IS 'pinching'.

But I'm sure the good people over at Zero Friction Tees will be sad to learn, that there is no friction between ball and tee anyway, so their product is useless.

EVERY shot generates backspin. 'Hitting down' on the ball generates MORE backspin.

I have given this plenty of thought, and as I mentioned, this is quite basic physics in action.

We'll probably never agree, and further debate is likely pointless.

Attached Images

pinching.jpg (9.8 KB, 10 views)

__________________
//Mox
2008 bag:
Mizuno MX-500 460cc 10.5* Fujikura Tour Platform 26.3 stiff. (about to be replaced by MP-600 10,5* UST Proforce V2 stiff)
Mizuno F-50 3w 15* Fujikura Tour Platform 26.3 stiff.
Wilson Deep Red 5w 18* Graphalloy Fatshaft stiff
Cleveland HALO 3i hybrid 22* graphite regular
Mizuno MP-60e forged 5i-PW True Temper Dynamic gold R300 steel
Mizuno MP Black OX raw haze 50/6 GW, 54/9 SW, 58/10 LW
Heavy Putter B3-M
Titleist NXT Extreme

Mox,

Please don't take my word for it, carry out some investigation and see what all scientific research reveals on the subject. I know that golfers feel like they are pinching the ball into the turf and that may well be a good swing thought that helps them, it does not detract from what actually happens though.

I am relating to you what I have deducted from scientific research using high speed photography and research into the ballistics of ball contact. It really does not mater to me if you wish to disbelieve it and I am not attempting to ridicule your theorising. I have had a number of these discussions but have not found them able to give a substantive argument.

Enjoy the game my friend.

__________________
Best Regards
Brian

________________________________
Funny o'l game!

hi Mox
how can you hit down on the ball when even with the ball on a tee and with a driver its the bottom half of the ball that compresses.
with an iron you cannot hit the ball downward as the face of the club has so much loft, the only way you can hit down is if you lean the shaft below your knees and even then you only come into the middle of the ball and not above the center. to hit down you have to apply downward pressure and it cant be done with a a golf club with the loft we use. try picking any club out your bag and try and do it you will see it imposable to do and it the loft of the face that stops you doing it. you cant push a ball downward using something wedged shaped like a golf club.
swinging down with a steep swing get you more backspin as the ball runs up the club face more. why do you get the same backspin when playing of fairways with short and long grass and playing it in the first cut of rough, playing out the rough you get less backspin only because grass gets between the face and the ball. if you nip the ball out the sand in a fairway bunker you can still get backspin and only take sand after the ball.
if you were to put a club against a ball in your hand you would see you cant hit down on a ball only swing down.
cheers
bill

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mox,

i agree with the whole "just because tiger says so" does not mean it is correct.

that being said, I do believe that there is a SLIGHT dowward force (probly less than .001psi) but I don't think that force that pinches against the ground has any effect on the ball.

the main purpose to hit down on the ball is so that you hit the ball 1st and the ground next. the reason you get more distance from hitting down on it has nothing to do with pinching, and little to do with delofting, but mostly it is from pure contact with the ball vs, turf slowing of club a bit then ball. as you said with sand, you can swing full blast but because you get sand between the club and ball you don't hit it very far at all.

btw, when i spoke of hitting the ball out of the sand and how the ball does not depress into the sand (once that ball does move .000001mm down in the sand, the groves and loft roll the ball up the face as brians link show) and it goes up and out like in that post i was refering to fairway bunkers, not greenside bunkers, where you want to hit the ball 1st before the sand via a descending blow so that you get maximum contact and power transfer and good spin and high launch if there is a big lip in front of you.

i agree it is a good swing thought, but that fact that the "pinching" actually adds to the distance.... that is one thing I would need to see some seroius research to prove that. but does it actaull impart a downward force (no matter how small or insignificant)? yes, i believe it does

Like I said - further debate would likely be pointless, but still ...

Bill, Yes - you CAN (and DO) apply forces in a direction into the ground. The wedge shape of the club does not change that. The MOTION of the wedge shape is relevant, and being downward as well as forward, it applies forces in both directions. Putting a static club head next to a ball is completely irrelevant. The club head MOVES at the time of impact, and during the time the ball is compressed. It moves forwards and DOWNWARDS.

Get a soccer ball. Put it on the ground. Place one finger on top of the ball (not necessary if you have 5000fps eyesight). Put your other hand - in a wedge shape - behind the ball, below the equator. Press directly forward. Will the ball slide? Yes - quite easily.
Now do the same, but instead of pushing directly forward with the "wedge hand", now press forward as well as downward. Will the ball slide? Yes it will. Just as easily? Not it won't! Why? Because the downward forces you apply to the ball is causing increased friction between the ball and the ground.

Try it with a balloon, you will easily see it compress into the ground.

The forces are there, and they are more than marginal.

Read bullet #3 here

Greg Norman has some feelings about this.
Short Game guru Dave Pelz:
That last article is actually a very good answer to the original question in this topic.


Oh - and for golfingguy - I don't think anybody is talking about distance. It's purely about spin-rate.


I choose to believe the combined knowledge of Tiger, Greg Norman, Dave Pelz and my high school physics teacher.

__________________
//Mox
2008 bag:
Mizuno MX-500 460cc 10.5* Fujikura Tour Platform 26.3 stiff. (about to be replaced by MP-600 10,5* UST Proforce V2 stiff)
Mizuno F-50 3w 15* Fujikura Tour Platform 26.3 stiff.
Wilson Deep Red 5w 18* Graphalloy Fatshaft stiff
Cleveland HALO 3i hybrid 22* graphite regular
Mizuno MP-60e forged 5i-PW True Temper Dynamic gold R300 steel
Mizuno MP Black OX raw haze 50/6 GW, 54/9 SW, 58/10 LW
Heavy Putter B3-M
Titleist NXT Extreme

Mox,

You are creating questionable statements to support an incorrect theory. Come on now, do you really believe the ball gets compressed between the tee and clubface in a way that can contribute to velocity and spin? The ball meets the face at force of around 2500 pounds

I agree that many eminent golfers claim that the ball gets trapped with the turf and that is how spin is generated but they are wrong, these people are not speaking from scientific experimentation they are talking of what it feels like, I am not convinced your school physics teacher ever studied club/ball ballistics either.

The tremendous forces created when the lofted clubface meets the ball pushes it backwards and upwards not downwards, how can soft earth and grass compress a golf ball that is struck with these forces. Take a golf ball and see if you can compress it in your hands, try it in a vice, it is very hard and does not compress easily, dirt has no chance.

Here is an excerpt again from Mt Tutelman's site that explains and he knows a bit about golf:

• Impact lasts no more than a half millisecond.
• The clubhead moves less than an inch during this time.
• The force between clubhead and ball can peak between 2000 and 3000 pounds. (It can average about 1900 pounds over the 0.4 millisec of impact. The peak is between 1.4 and 2 times the average force.)

So what is actually going on during that half-millisecond or so of impact? Here's the story, as described by Cochran & Stobbs -- and in somewhat more detail by Gobush:

1. In the first microsecond of impact, we have the irresistable force meeting the immovable object. The ball has to react somehow to the momentum of the clubhead, and the least-energy way it can react is by moving up the lofted clubface. Initially it slides up the clubface, because there isn't enough friction yet between clubface and ball. But all that is about to change very quickly.
2. The ball cannot acclerate to an upwards velocity in no time at all; that would require infinite acceleration, which requires infinite force. So it can't get completely out of the way of the clubhead just by sliding upwards. It begins to compress on the clubface, which creates a force between the clubface and the ball. If you don't think this is a large force, just try to compress a golf ball by 30% of its diameter using your fingers. Not even close! OK, use a vise; it's still very hard to apply that much compression force. Remember, this is a force that averages almost 2000 pounds during impact, and can easily peak around 3000 pounds. This force of compression does two important things:
   • It begins to accelerate the ball with a horizontal component, not just the vertical motion up the clubface.
   • It creates a lot of friction between ball and clubface. So, instead of sliding up the clubface, the ball begins to roll instead.
3. The ball continues accelerating upwards (due to the loft) and horizontally (due to the compressive force). The sliding has turned completely into roll, so the upwards acceleration increases the speed of roll. At some point, the momentum absorbed from the clubhead through acceleration has the ball moving faster than the clubhead. In other words, the elastic rebound of the ball's acceleration allows the ball to release from the clubhead. At this instant, its launch conditions are determined.

__________________
Best Regards
Brian

________________________________
Funny o'l game!

nice links and explination brian

Ok, so you are now telling me, that the ball moves up, based on forces pushing down and forward?

Imagine that the ball was under no influence from gravity and hanging freely in midair, with no contact with the ground.

Now hit it with forces moving down and forward. Will the ball move up?


That ball begins sliding upwards, because it reacts to the downward force applied.
Action equals reaction, remember.

Explain why spinrates are different from fairway to sand and to hardpan, if friction is not involved. Have you ever tried to hit a spinning shot off a concrete path? It'll spin like crazy!

Never mind. This is pointless. Forget about it. We just disagree. I'm not going to bother anymore.

__________________
//Mox
2008 bag:
Mizuno MX-500 460cc 10.5* Fujikura Tour Platform 26.3 stiff. (about to be replaced by MP-600 10,5* UST Proforce V2 stiff)
Mizuno F-50 3w 15* Fujikura Tour Platform 26.3 stiff.
Wilson Deep Red 5w 18* Graphalloy Fatshaft stiff
Cleveland HALO 3i hybrid 22* graphite regular
Mizuno MP-60e forged 5i-PW True Temper Dynamic gold R300 steel
Mizuno MP Black OX raw haze 50/6 GW, 54/9 SW, 58/10 LW
Heavy Putter B3-M
Titleist NXT Extreme

hi Mox
the ball moves up because of the loft of the club face. how much it moves up depends on how much loft id applied. that why when using a putter the ball hardly lifts of the ground at all and why with a one iron the ball comes off the face of the club lower than if you used a wedge. the angle of loft makes the ball compress into the face and the angle of the face determines the angle the ball leaves the club face.
again it is not a downward hit on the ball as the face of the club hits below the center of the ball and that gives the ball and upward blow not a downward blow.
if you hit the ball with a club with no loft then the ball would travel in a slightly downward motion. but you don't you use a club with loft then the ball leaves the face on the same angle as the face. if you have a 10.5% driver then the ball comes of the face about 12%, if you use a 52% wedge the ball comes of the face about 52/54%.
if what you say was true then people in hat sunny places would be playing on hard fairways and people like me on most wet fairways and our clubs would have to be tweaked for the diffrent conditions as we cant trap the ball the same as the ground is harder there and softer here. that just does not happen.
cheers
bill

__________________
ping zing2 metal driver
ping zing2 metal 3 wood
ping eye2 1 iron
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ping zing2 52% s/wedge
ping mb 56% wedge
ping c10 G2I broom handled putter
top flight "T" golf balls
white ping bag

Regarding hardpan and a fluffy lie:

Have you ever noticed how a ball that's "sitting up" will fly higher when struck than a ball that is resting upon hard pan? The launch angle is greater in the first case because the ball's centroid is situated higher than the clubhead's centroid at impact.

In this illustration, (Dam, it has been deleted somehow) we show two situations. At the left, we show a golf ball sitting pretty close to the ground at impact. On the right, we show a ball that's "sitting up", perhaps upon a tuft of grass. Those arrows do not represent the respective launch angles. They simply illustrate the relative positions of the centroids at impact. (Aside: The higher the arrow points, the more the clubhead's face angle will increase at impact due to temporary bending, further complicating calculations!)

When momentum is transferred from the club to the ball on the left, the launch angle will be shallow because the ball's centroid is not much higher than the clubhead's.

But a ball that sits up has an elevated centroid which a golfer can easily "get under". In this case, the club's centroid is so low with respect to the ball's that this launch angle is likely to be quite vertical and a flop shot will result.


That's OK Mox, I am not looking for a bust up only debating what happens to golf balls at impact Lets leave it at that then my friend.

__________________
Best Regards
Brian

________________________________
Funny o'l game!

Great debate guys,

I'm in Brian and Bills school here.

If Norman reckons he contacts the ball on the upper rear quadrant of the ball for extra spin, he is a little dillusional! If we'd hit a ball there you just bury it in the ground.

It is physically impossible to hit the ball any higher than the equator if we are to get it air born. Even though the clubhead mass is moving in a slightly descending direction, the loft on the face (and ball position depending on 2 iron or wedge) is at an angle greater than the angle of descent. Always. Hence the ball cannot move down. Even for 0.0000000000001 seconds.

Even if we hit it flat, square on the equator of the ball (the highest point possible) we would need a club with negative loft to place any force into the ground through the ball.

So, clubhead mass goes slightly downwards, loft of club is always greater than angle of descent, combination of the two = piercing shot with plenty of spin.

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Luke: I don't believe it!
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[quote=Neil18;10551983]
It is physically impossible to hit the ball any higher than the equator if we are to get it air born. Even though the clubhead mass is moving in a slightly descending direction, the loft on the face (and ball position depending on 2 iron or wedge) is at an angle greater than the angle of descent. Always. Hence the ball cannot move down. Even for 0.0000000000001 seconds.
[quote]

Have you ever seen a billards player hit a massé shot?

It is absolutely possible to hit a ball higher than the equator, and it WILL compress the the ball into the ground and kick it into the air with massive backspin.

It's a matter of DIRECTION how forces is applied to the ball. The loft only has influence as the ball react to the forces applied!

__________________
//Mox
2008 bag:
Mizuno MX-500 460cc 10.5* Fujikura Tour Platform 26.3 stiff. (about to be replaced by MP-600 10,5* UST Proforce V2 stiff)
Mizuno F-50 3w 15* Fujikura Tour Platform 26.3 stiff.
Wilson Deep Red 5w 18* Graphalloy Fatshaft stiff
Cleveland HALO 3i hybrid 22* graphite regular
Mizuno MP-60e forged 5i-PW True Temper Dynamic gold R300 steel
Mizuno MP Black OX raw haze 50/6 GW, 54/9 SW, 58/10 LW
Heavy Putter B3-M
Titleist NXT Extreme

Mox Mox Mox!

Now I understand where our differences are!

You're playing golf with a cue!

I should have said "you can't hit the ball above the equator with a golf club"!

As we are using clubs, not cues, your example (although a valiant attempt) is not applicable.

The only way to hit a golf ball with a golf club above the equator is to thin it, or ram it straight into the ground with negative loft.