reducing spin on drives

[Beachcomber]

Originally Posted by onesome

Looks the opposite to me,guy on left has ascending impact and guy on right descending.

onesome, you have to look at the left armpit/shoulder.  That is low point.

After low point - the club indeed will make an ascending path (up).  Both golfers are swinging up.  The thing that is ideal about Grant Waite, golfer on the right, is that his handle of the club is forward - thus the club is still in state of angular acceleration... Accelerating... Going faster... Speeding up.

The golfer on the left - his club handle is inline with the club head... Meaning his club has already reached maximum speed... And is considered to be entering a state of angular deceleration (also referred to as 'throwaway').

There are a few other interesting items that must be noted as ideal when looking at Grant Waite (golfer on the right).  Given that he is hitting up with the driver - along with the forward shaft lean (handle is slightly ahead of the clubhead)... Grant has delofted the driver... Thus the lower the loft - the less the clubhead will be slowed by impact forces.  So even if the golfer on the left is matching the swing speed of Grant on the right... Grant is imparting higher force onto the golf ball - than the golfer on the left.  Meaning Grants ball is going to leave the club at a higher ball speed - due in large part to the forward shaft lean.

Basic Laws of Physics and Geometry... Trackman will spit these numbers out all day long and prove these points.

[Beachcomber]

Originally Posted by mvmac

Who's this Grant Waite guy?

I don't know?  But I'd like to meet him.  He looks like he can swing the golf club?

[luu5]

Originally Posted by Beachcomber

First, make sure you understand Attack Angle.  So below -5 (hitting down) is not good - as shown in the previous post that I made with the Trackman data.  Therefore, you want to hit up on the driver.

Is this picture really an optimal case? Looks like player has flipped as the clubhead seems to be passing the handle. Spin on the ball would be caused by the loft of the club (+possible shaft bend).

I would think the best would be handle ahead or inline with clubhead, but the clubhead ascending. So the spin would be reduced even more as the "topspin" caused by clubhead moving up and through the ball, not just through. Take the clubhead in the first picture and put it in the second picture, but leave the arrows intact. Extreme with handle that much forward, but perhaps understood?

[Beachcomber]

Is this picture really an optimal case? Looks like player has flipped as the clubhead seems to be passing the handle. Spin on the ball would be caused by the loft of the club (+possible shaft bend). I would think the best would be handle ahead or inline with clubhead, but the clubhead ascending. So the spin would be reduced even more as the "topspin" caused by clubhead moving up and through the ball, not just through. Take the clubhead in the first picture and put it in the second picture, but leave the arrows intact. Extreme with handle that much forward, but perhaps understood?

Correct! But I couldnt find a picture which represented that illustration. If someone can photo shop that image maybe it would be a better representative?

[Stretch]

Originally Posted by mvmac

Who's this Grant Waite guy?

No idea, but I recently started training with this dude and think they'd make a really terrific team!

[broomhandle]

Originally Posted by luu5

Is this picture really an optimal case? Looks like player has flipped as the clubhead seems to be passing the handle. Spin on the ball would be caused by the loft of the club (+possible shaft bend).

I would think the best would be handle ahead or inline with clubhead, but the clubhead ascending. So the spin would be reduced even more as the "topspin" caused by clubhead moving up and through the ball, not just through. Take the clubhead in the first picture and put it in the second picture, but leave the arrows intact. Extreme with handle that much forward, but perhaps understood?

The pictures are so far out of scale that what you are suggesting would represent a true topspin shot.

The first pic has negative dynamic loft AND negative attack angle and would result in a 'carry' of about an inch and a half :)

Second picture wouldn't represent a flip if the left arm was at the same angle as the shaft.

[luu5]

Originally Posted by broomhandle

The pictures are so far out of scale that what you are suggesting would represent a true topspin shot.

The first pic has negative dynamic loft AND negative attack angle and would result in a 'carry' of about an inch and a half :)

Second picture wouldn't represent a flip if the left arm was at the same angle as the shaft.

I wrote "extreme", but look at the picture "Gator Hater" posted.

[Golfingdad]

Originally Posted by Beachcomber

onesome, you have to look at the left armpit/shoulder.  That is low point.

After low point - the club indeed will make an ascending path (up).  Both golfers are swinging up.  The thing that is ideal about Grant Waite, golfer on the right, is that his handle of the club is forward - thus the club is still in state of angular acceleration... Accelerating... Going faster... Speeding up.

The golfer on the left - his club handle is inline with the club head... Meaning his club has already reached maximum speed... And is considered to be entering a state of angular deceleration (also referred to as 'throwaway').

There are a few other interesting items that must be noted as ideal when looking at Grant Waite (golfer on the right).  Given that he is hitting up with the driver - along with the forward shaft lean (handle is slightly ahead of the clubhead)... Grant has delofted the driver... Thus the lower the loft - the less the clubhead will be slowed by impact forces.  So even if the golfer on the left is matching the swing speed of Grant on the right... Grant is imparting higher force onto the golf ball - than the golfer on the left.  Meaning Grants ball is going to leave the club at a higher ball speed - due in large part to the forward shaft lean.

Basic Laws of Physics and Geometry... Trackman will spit these numbers out all day long and prove these points.

I am a physics/geometry guy, so I shouldn't be having trouble understanding this but, alas, I am.  I was under the impression that the low point of the swing would have to occur when the shaft is straight vertical with no forward (or backwards) lean.  Thus, to catch it on the upswing, you would have to - in effect - be flipping a little bit.  Also, your D-plane would have you catching the ball at a little out-to-in angle making it difficult to draw the ball.

I know I'm wrong, I just want to understand exactly how.  I'm guessing it has something to do with the shoulders, though, because if I have forward shaft lean on a club that is moving upwards, then that left shoulder HAS to go going up, right?

[iacas]

Originally Posted by Beachcomber

First, make sure you understand Attack Angle.

Pretty sure he's good with that. :)

[broomhandle]

Originally Posted by Golfingdad

I am a physics/geometry guy, so I shouldn't be having trouble understanding this but, alas, I am.  I was under the impression that the low point of the swing would have to occur when the shaft is straight vertical with no forward (or backwards) lean.  Thus, to catch it on the upswing, you would have to - in effect - be flipping a little bit.  Also, your D-plane would have you catching the ball at a little out-to-in angle making it difficult to draw the ball.

I know I'm wrong, I just want to understand exactly how.  I'm guessing it has something to do with the shoulders, though, because if I have forward shaft lean on a club that is moving upwards, then that left shoulder HAS to go going up, right?

With the first order approximation of a 1-lever swing of constant radius around a steady center the low point MUST BE when the imaginary line between the center and the clubhead is straight vertical. Makes no difference how the body parts are arranged so long as they don't change the radius to the clubhead or move the center.

With a real full golf swing with centers of rotation around at least the left wrist, left shoulder and spine and the center quite probably moving a bit it gets heinously complicated. Generally, I think the left arm swing from the shoulder is dominant around impact and low point is when the imaginary line between the shoulder joint and clubhead is vertical. If the hands are leading the club then that imaginary line is a bit shorter but it's still the verticality of the imaginary line and not the arm or shaft angles that defines low point.

I think the left shoulder is coming up through impact on EVERY remotely competent golf swing. The left arm swing from the shoulder and the arm-club angle releasing and lengthening the lever make most swings downward blows.

[iacas]

Originally Posted by Golfingdad

I am a physics/geometry guy, so I shouldn't be having trouble understanding this but, alas, I am.  I was under the impression that the low point of the swing would have to occur when the shaft is straight vertical with no forward (or backwards) lean.  Thus, to catch it on the upswing, you would have to - in effect - be flipping a little bit.  Also, your D-plane would have you catching the ball at a little out-to-in angle making it difficult to draw the ball.

I know I'm wrong, I just want to understand exactly how.  I'm guessing it has something to do with the shoulders, though, because if I have forward shaft lean on a club that is moving upwards, then that left shoulder HAS to go going up, right?

Low point tends to be around the left shoulder. As broomhandle said, it's closer to a double pendulum. The center of rotation is near the base of the neck (between the shoulders), which pulls the left shoulder up, and then the wrists have lag, reach inline, and then pass inline. The lever (shoulder-clubhead) is longest when it's inline, but you can reach low point in a wide area if you reach inline too early or too late given the way the left shoulder works up almost the entire downswing.

[Golfingdad]

Originally Posted by broomhandle

With the first order approximation of a 1-lever swing of constant radius around a steady center the low point MUST BE when the imaginary line between the center and the clubhead is straight vertical. Makes no difference how the body parts are arranged so long as they don't change the radius to the clubhead or move the center.

With a real full golf swing with centers of rotation around at least the left wrist, left shoulder and spine and the center quite probably moving a bit it gets heinously complicated. Generally, I think the left arm swing from the shoulder is dominant around impact and low point is when the imaginary line between the shoulder joint and clubhead is vertical. If the hands are leading the club then that imaginary line is a bit shorter but it's still the verticality of the imaginary line and not the arm or shaft angles that defines low point.

I think the left shoulder is coming up through impact on EVERY remotely competent golf swing. The left arm swing from the shoulder and the arm-club angle releasing and lengthening the lever make most swings downward blows.

Originally Posted by iacas

Low point tends to be around the left shoulder. As broomhandle said, it's closer to a double pendulum. The center of rotation is near the base of the neck (between the shoulders), which pulls the left shoulder up, and then the wrists have lag, reach inline, and then pass inline. The lever (shoulder-clubhead) is longest when it's inline, but you can reach low point in a wide area if you reach inline too early or too late given the way the left shoulder works up almost the entire downswing.

OK, I got it.  I now have other random things rattling around in my head regarding dynamic loft but at least I understand the attack angle now.  Thanks.

[Beachcomber]

Originally Posted by iacas

Pretty sure he's good with that. :)

Sorry, I wasn't responding to Gator with that... More of a general statement to readers of this forum - that come into this thread - who may not understand Attack Angle.

[broomhandle]

Originally Posted by Beachcomber

You should also understand Attack Angle - and its importance and relationship to Spin (Launch and Loft).  Following is a Trackman driver fitting chart which shows that having a positive Attack Angle will reduce your Launch Spin - but increase your Vertical Launch.  So the ball will fly higher - but with less spin.  Ultimately, your Ball Speed increases, and the result is your ball will fly further - increasing both your Carry and Total Distances.

-5 is swinging down - descending blow at impact.

0 is level at impact.

+5 is swinging up - ascending blow at impact.

I believe you're mis-applying this particular chart. This seems to be a chart for FITTING YOUR DRIVER to a given swing type.

This show's that IF you swing down you need a lot more loft in your driver to maximize your carry than IF you swing up.

And the carry for the guy who swings down will still be less than the guy who swings up.

This is NOT a chart of what happens if you swing THE SAME CLUB at different AOA's.

I've seen one of those somewhere and it showed greater efficiency for positive AOA but negligible difference in spin rate.

I have no problem with your conclusion that positive AOA is desirable but I think you're presenting the wrong data to support it.

[iacas]

Originally Posted by broomhandle

I believe you're mis-applying this particular chart. This seems to be a chart for FITTING YOUR DRIVER to a given swing type.

This show's that IF you swing down you need a lot more loft in your driver to maximize your carry than IF you swing up.

And the carry for the guy who swings down will still be less than the guy who swings up.

Even if the chart was intended for what you say, the fact of the matter is that the bold statement can still be used to prove that hitting up = better than hitting down. You see that, yes?

[broomhandle]

Quote:

Originally Posted by iacas

Even if the chart was intended for what you say, the fact of the matter is that the bold statement can still be used to prove that hitting up = better than hitting down. You see that, yes?

Yes, which is why my post included this phrase:

Quote:

"I have no problem with your conclusion that positive AOA is desirable "

I believe the difference in spin rates between neg and pos AOA is VERY misleading if you don't understand exactly what that chart is.

No way that swinging up produces a 7 degree decrease in spin loft with the same club . If anything the tendency for most would be to release a bit more and add a tad of loft

[iacas]

Originally Posted by broomhandle

I believe the difference in spin rates between neg and pos AOA is VERY misleading if you don't understand exactly what that chart is.

No way that swinging up produces a 7 degree decrease in spin loft with the same club. If anything the tendency for most would be to release a bit more and add a tad of loft

I think you're misunderstanding what spin loft is. Spin Loft is the difference between the dynamic loft and the angle of attack. That's why lower spin loft produces lower spin.

[broomhandle]

Originally Posted by iacas

I think you're misunderstanding what spin loft is. Spin Loft is the difference between the dynamic loft and the angle of attack. That's why lower spin loft produces lower spin.

I understand just fine. It's translating my understanding to Trackman's terms AND your terms that is a struggle.
Trackman says - SL = DL - AOA   - agrees with you

There may be a difference between you and trackman in definition of dynamic loft.

Trackman's seems to be DL = Static Loft +- shaft lean + AOA

so substituting formula 2 into formula 1 gives Spin Loft = Static Loft +/- shaft lean + aoa -aoa

spin loft = static loft +/- shaft lean

assume a neutral shaft for simplicity and spin loft = static loft

10* driver 5* down:

dl = 10-5 = 5

sl = 5--5 = 10

10* drive 5* up:

dl = 10 + 5 = 15

sl = 15 - 5 = 10

Trackman says this:

TrackMan has seen that spin loft (the

difference between angle of attack and dynamic loft; SPIN

LOFT = DYNAMIC LOFT – ANGLE OF ATTACK) remains

virtually constant for a particular golfer, given club loft and

club speed, no matter what the attack angle is. This means

the myth that “hitting down on the ball creates more spin” is

not true. For example, Moving the ball back in the stance

generally creates a more negative attack angle, but the dynamic

loft will be offset by a similar amount, resulting in an

unchanged spin loft and thereby unchanged spin rate.

Where is that thread where you changed your mind about recommending a positive AOA to average golfers? I think the trackman data that showed very similar spin when swinging the same club up or down was in there. Nevermind, I found the thread and the chart I think I remember isn't there.