AOA to LAUNCH ANGLE - SPIN SAVED or LOST - LOFT COMPENSATION NEEDED

[Howard_Jones]

Angle of attack itself, is such a small contributor to spin values, we can forget it, but since AOA makes a influence on the ratio from Dynamic loft to launch angle, our benefit is the need for less loft, to get to the same "target" launch angle, and that way save spin. The spin savings comes indirectly, NOT directly, so here is how it works for a player with 100 mph club speed

, and all scenarios from a AOA of minus 5* to plus 5*

LAUNCH ANGLE VS DYNAMIC LOFT VS AOA
- The numbers is the expected launch angle from the Dynamic loft specified, and the given AOA

 

The practical use of AOA is to determine the need for LOFT to get to our wanted launch angle.
If we simplify it, and say 4* of loft will always be added by the shaft/swing, we can used the Dynamic loft to launch ratio to make a chart like this, so it becomes visible, its ALL about what loft should we play

Since the LA lost is larger from minus 5 to 0, than it is from 0 to plus 5, the best equalize of the 3 launch angle is with a loft ratio like this.
- AOA +5* = 9.0* Loft
- AOA 0* = 10* Loft 
- AOA -5 = 11.5* Loft

- AOA +5  = 9* static loft + 4* (basic addition from shaft) = 13* Dynamic loft x 0.91 = 11.8* launch
- AOA 0* = 10* + 4 = 14 DL x 0.85 = 11.9* launch
- AOA -5 = 11.5* +4 = 15.5 DL x 0.768 =11.9 * Launch angle 



The AOA to loft ratio who say from 0 to plus 5* we need 1 extra loft, and from -5* to 0* we need 1.5 extra loft, is a very good rule of thumb like this chart shows you



This gives us the chance to finally ISOLATE what it cost as SPIN to have a negative AOA
If your AOA is 0*, you need 1 extra loft to get the same launch angle as you would at -5* AOA
If your AOA is -5*, you need 1.5* Extra loft to get to the same launch as a AOA of 0, and 2.5* of loft if you want the same launch as +5*

This becomes the "price list" for SPIN vs AOA to equalize launch angle




Since AOA gives a different gear ratio from Dynamic loft to launch, this chart show how much launch angle we gain or loose vs 0 AOA using the same club.
Example with 17 dynamic loft - +5 gives a gain of 1.0 to launch angle, and -5*AOA gives a loss of 1.4 on launch vs the same club and 0* AOA
so from minus 5 to plus 5 with 17* as dynamic loft, the gain of launch is the summary or 2.4* as addition to launch, using the same club.



LOFT SAVED (free loft vs AOA) or LOST - or how much loft difference "gained or lost" or as needed compensation vs 0* AOA
The player with minus 5 AOA and 17 Dynamic loft, will need 1.8 + 1.1 = 2.9 or 3.0 more static or dynamic loft to get the same launch angle as the player with +5*, thats why he will have to pay with SPIN  from that extra loft to get there.



THE PRACTICAL EXAMPLE
Still 17 dynamic loft, and a player who can change his swing from -3* to +2.0* or a change of 5*, "saves" 1.0 + 0.5 = 1.5 on loft, so if he now plays a 10.5* he will get the same launch from a 9.0* and the benefit from cutting of 1.5 on loft, and by that reduction in spin, all due to his change of AOA.
His spin reduction from the lower loft, shall give him a benefit of 270-121 = 391 rpm (see the chart below here)

SPIN SAVED or AS COST
We stay with 17 Dynamic loft, and can see that the player with +5* have a spin save of 271 Rpm vs a 0* AOA
The player with -5* and 17 Dynamic loft, will have to pay with 2.9 extra loft to get there who cost 472+291 = 763 rpm



So, a positive AOA itself dont really matter for spin, IMPACT position does, but as you can see, we gain launch, and thats positive, and we can use a lower lofted head to get to our target launch angle, and save spin that way.

THE GAINS AS YARDS
Since a change of AOA influence on launch via the gear ratio, and the actual spin gain comes from the option to use lower loft, our scenario with 150 ball speed, 2350 rpm, and a dynamic loft of 17, gives a launch angle of 14.9 with +5 as AOA. Lets use that as target, and see how our example player who can change his swing from -3* to plus 2*, and by that could use a 9.0* driver instead of a 10.5* - Ball speed and launch remains the same, only spin changes with 391 rpm from 1.5* lower loft.



A swing change itself is not the way to more distance, if club speed and impact remains as before, and thats why most will benefit from a driver fitting, A REAL ONE, since thats where both distance and dispersion comes from.

SECOND SCENARIO - SHOT 3
If 2 players with the same dynamic loft of 17*, had 5* as difference to AOA, but played the same static loft, they they will have the same ball speed and spin, but a different launch angle due to the AOA gear ratio. (Shot 3 falls down to 13.7 on launch, due to a negativ AOA of -3*)


Thats why AOA itself dont really matters, its takes way to large of a differences to make a difference to distance that matters in play..


If you have a good swing, DONT get hung up in AOA, FOCUS on impact position since thats where we very easy loose or gain distance, and for the 100 mph player, a decent but low heel side impact, vs a ideal impact slightly above the centerline against the toe side, gives 16 yards difference or more to carry, and potentially 25 yards more on total. Tweaks on AOA can be silly hard, and cant really pay off, so just use more static loft when more launch is wanted.

For each 1/8" we move impact higher, expect spin to drop with 240 Rpm as average, and launch angle to go up 0.35* average
Thats why impact position on the face should be focus, NOT angle of attack

COMPARED
If the player now makes impact in the BLUE area, and has a NEGATIVE AOA, then its typical that AOA gets the blame for spin, but it hardly ever is, its vertical gear effects who is the ruler of spin.

If the player with 17 Dynamic loft, made impact on the BLUE spot, and moved it to the RED, improvement to launch would be 2.0, (it takes a change of AOA with 8.0* to to gain the same with 17* as Dynamic loft). His spin will drop with about 1450, so we can cut off unneeded spin this way, and by that, DONT worry about what static loft you need, let gear effect eat the spin, so its no need for a swing change if your swing is good.

 

HOW TO TUNE UP YOUR DRIVER - DIY
 

,
 

 

 

Edited March 20, 2023 by Howard_Jones

[ezra76]

Thank you. I have one question, how do go about figuring dynamic loft? Or is that something I've need from the monitor to tell me? I know my AoA and the loft of the driver.

 

I'm working on teeing a little lower and making more consistent contact. I have AoA to spare and although it's been fun gaining distance over the winter I'm working on getting my old cut shot back in action to keep it in play. I have a few little tournaments and a league starting next month so time to get it dialed in for accuracy. 

Edited March 17, 2023 by ezra76

[GungHoGolf]

1 hour ago, ezra76 said:

I have one question, how do go about figuring dynamic loft? Or is that something I've need from the monitor to tell me? I know my AoA and the loft of the driver.

You’ll need a launch monitor to tell you your dynamic loft. What monitor are you using that tells you AoA but not dynamic loft?

 

 

[nkurz]

Let me start by saying that I'm an interested amateur, and Howard is an experienced professional.  I feel like I understand the physics involved reasonably well, and think I mostly understand my own swing, but I've never done a fitting for anyone else.  

 

Tone is hard on the internet, and I'd ask you to read this as "confused" rather than "accusatory".  Line by line, I think I agree with everything Howard says. But the perspective here is so foreign to me that I think I must be missing something major:  Why would we assume that the dynamic loft would stay constant while the angle of attack changes?  

 

If I've got the terms right, Dynamic Loft is the angle of the face of the club at impact relative to the horizon.  It can be broken into two components:  Spin Loft  and Angle of Attack.  Spin Loft, as the name implies, is the portion of the loft that affects spin.   If you increase SL, you get a bit more spin (about 300 rpm per degree) and a Launch Angle that is higher by about .85 degrees for each degree of loft added. If you increase AOA with no changes to anything else, spin is unchanged and Launch Angle increases 1 for 1. 

 

What launch monitors have taught us is that golfers with relatively high swing speed (call it 100 mph+) who want to maximize their drive distance often benefit from having a higher launch angle and lower spin than can be achieved by simply using a high lofted club.   To achieve this difficult combination, they  either need to hit the ball above the clubs Center of Gravity and take advantage of Gear Effect, they need to hit the both with an upward (positive) Angle of Attack, or both.   

 

In my view, the "normal" way that a golfer would increase AOA with a driver is to tee the ball higher and farther forward, so that the ball is impacted on the upswing after the bottom of the arc.   Doing this increases the Dynamic Loft (SL + AOA) by the same amount the AOA increases, but since the Spin Loft is constant, the spin doesn't increase.   The Launch Angle increases by the same amount as the AOA, and they get a drive with significantly higher launch with no increase in spin.  

 

But in Howard's model, as part of increasing they AOA, they simultaneously change something else in their swing so as to keep the Dynamic Loft constant.  The obvious way of doing this would be to increase forward shaft lean at impact by the same amount that AOA increases, but maybe there is some other way? In any case, I'm doubtful that this is common, and not even sure it's always possible to do this while maintaining a constant swing speed across the full -5 to +5 range he talks about.  

 

The end result is that instead of getting a 1:1 increase in Launch Angle, they get only a very small increase in Launch Angle.  Howard concludes from this that AOA is not worth trying to change, since the benefits from a large change are so small.  He's not logically wrong about this conclusion, but I think it depends almost completely on his assumption that Dynamic Loft remains constant, and thus Launch Angle only changes minimally.  If you were to instead assume that Launch Angle increases directly with AOA, I think you'd reach the opposite conclusion. 

 

So which assumption is right?  Without tackling the bigger question of whether AOA changes are worth pursuing, it seems like this would be easy to answer.  If you take a golfer with a 0 AOA who is hitting the ball at the bottom of their arc, and have them tee the ball a 1/2" higher and 4" forward while keeping their swing exactly the same (guessing at numbers, use whatever produces a +5 AOA), does their Launch Angle tend to be 1 degree higher or 5 degrees higher?   

 

Closing the way I began, Howard definitely knows at least 10x as much about real golfers in the real world than I do.  He might be right here, but I'd like to understand why, because if he is then a lot of my intuition is probably wrong.  

 

 

 

 

 

 

 

 

 

[Howard_Jones]

1 hour ago, nkurz said:

Let me start by saying that I'm an interested amateur, and Howard is an experienced professional.  I feel like I understand the physics involved reasonably well, and think I mostly understand my own swing, but I've never done a fitting for anyone else.  

 

Tone is hard on the internet, and I'd ask you to read this as "confused" rather than "accusatory".  Line by line, I think I agree with everything Howard says. But the perspective here is so foreign to me that I think I must be missing something major:  Why would we assume that the dynamic loft would stay constant while the angle of attack changes?  

 

To make a example we need to start from something, and the example 17 was chosen since a area of 15% launch is very good for 100 mph club speed. The ratio from Dynamic loft to launch is NOT FIXED, but vary with AOA, but dont think there is a 1:1 ratio where +1.0* on AOA = 1.0* on lanch.

LOFT Deliver launch angle
AOA does not change loft, ONLY the gear ratio

17 Dynamic loft with a positive AOA of +5* = 15.5* as Launch angle
17 Dynamic loft with a neutral AOA of 0* = 14.5* as Launch angle
17 Dynamic loft with a negative AOA of -5* = 13.1* as Launch angle

We have 10 as difference to AOA, but only 2.4* as difference on launch, so the average become 0.24* for each 1.0 change of AOA into positive. 
- From 0 to plus 5 the average is only 0.20*
- From -5 to zero the average is 0.28*

Why the same dynamic loft?
Dynamic loft is a product of static loft and shaft bending, and the same player load a release the shaft about the same every time, so "all else equal"dynamic loft will be a value we can use as a constant. If we shall assume that more forward or higher tee = more positiv AOA and always will change dynamic loft (higher), then we are making a bit to many assumptions when the task was to isolate AOA itself, and the influence it has for a 100 MPH player. 

If its for launch angle reasons, we simply use more static loft.

Edited March 17, 2023 by Howard_Jones

[Glock917]

In regards to face impact position. I haven’t research it too meticulously but I saw a video of pings new g430 drivers having a different bulge and roll wear low misses spin less and launch higher and heel misses spin less and launch lower of that sorts. It was with the ping guy Marty that’s the spokesman for most ping tech and the stack system. 
 

I guess I’m curious on your view on that and my curiosity is bulge and roll been around since metal woods so why hasn’t this type of bulge and roll been done before? Or is it just overzealous marketing claims like twist face. 

[Howard_Jones]

4 minutes ago, Glock917 said:

In regards to face impact position. I haven’t research it too meticulously but I saw a video of pings new g430 drivers having a different bulge and roll wear low misses spin less and launch higher and heel misses spin less and launch lower of that sorts. It was with the ping guy Marty that’s the spokesman for most ping tech and the stack system. 
 

I guess I’m curious on your view on that and my curiosity is bulge and roll been around since metal woods so why hasn’t this type of bulge and roll been done before? Or is it just overzealous marketing claims like twist face. 

Tom Wishon was the first who left the classic "Bulge and Roll" thinking with his first GRT model 515 in 2004.



Talormade has their "Twist face" model
https://www.taylormadegolf.com/m3-m4-drivers.html#

They can stabilize LAUNCH angle (GRT), and to a certain point direction, while spin values will still be ruled by vertical gear effects, and thats a VCOG / RCOG and MOI value question, where the shaft has a certain influence, while the face on the club does not matter for spin itself.
 

[Howard_Jones]

6 hours ago, ezra76 said:

Thank you. I have one question, how do go about figuring dynamic loft? Or is that something I've need from the monitor to tell me? I know my AoA and the loft of the driver.

 

I'm working on teeing a little lower and making more consistent contact. I have AoA to spare and although it's been fun gaining distance over the winter I'm working on getting my old cut shot back in action to keep it in play. I have a few little tournaments and a league starting next month so time to get it dialed in for accuracy. 

If you know your Angle of attack, you now have all the numbers needed to figure out whats your dynamic loft.



EXAMPLE
- Your AOA is +3, average, and your launch angle is 14.0 average
That correspond with a dynamic loft of 16

If your head is 10.5 - 5.5 was added from shaft bending/swing 
 

Edited March 17, 2023 by Howard_Jones

[nkurz]

Thanks for responding gently!  To start, and I probably should have done this at the beginning, let's make sure we're using the same definitions.  I now realize that I may have already messed up on some of them.  But from here forward, does this diagram agree with the way you are defining things?  

 

 

 

1 hour ago, Howard_Jones said:

The ratio from Dynamic loft to launch is NOT FIXED, but vary with AOA, but dont think there is a 1:1 ratio where +1.0* on AOA = 1.0* on lanch.

 

Well, maybe this is where I'm wrong, because I feel confident about this.  Perhaps it depends on how we define "fixed" and "all else equal".  My version of "all else equal" would go like this.  Assume we set up Iron Byron to hit a driver at 100 mph with a 0 AOA with a 17 Dynamic Loft, which (let's say) produces something a 14 degree Launch Angle and 2300 rpm.  

 

Then without changing any settings, we put the machine on a ramp pointed 5 degrees up.  If we assume the swing is the same, I'd contend that this would produce a shot with a 19 degree Launch Angle, also at 2300 rpm.  If we put it on a ramp slanted down at 5 degrees, I'd expect a 9 degree launch with the same spin.    

 

In this admittedly somewhat contrived case, I'd expect the Launch Angle to change 1:1 with the change in AOA and the Spin Loft (and hence the spin) would remain constant.  The Dynamic Loft would also change the same number of degrees as AOA, but as you say, the ratio of Dynamic Loft to Launch Angle would not be constant.  

 

The question would then become whether a golfer changing their driver AOA by teeing the ball higher and farther forward is equivalent to putting Iron Byron on a ramp.  Based on my own experience, my guess is that it's more similar a ramp than assuming a constant Dynamic Loft, but I don't have measurements.  Is your thought that something else reliably happens when a real golfer tries to hit a ball on the upswing that causes them to keep the club face pointing low? 

 

1 hour ago, Howard_Jones said:

AOA does not change loft, ONLY the gear ratio

 

That might be another way of phrasing the question.  I agree that changing AOA does not change loft if club orientation is unchanged (see diagram above), but I think changing AOA almost always changes club orientation.  For a high positive AOA, I have trouble picturing how the club could be delivered to that it wouldn't.   Do you assume changing AOA typically does not change club orientation?  Also what do you mean by "gear ratio" in this context?

 

 

 

[Howard_Jones]

SPIN loft comes up short real life, we will not be able to use it to explain spin.

The others is just like i work with them
Dynamic loft is simply the loft the club has at impact
Its NOT related to AOA, thats only the travel direction of COG

Its just like when we open or closes face angle
- When we close it, COGs travel direction remains the same,
but now its travel direction goes toe side
- When we open it, COGs travel direction remains the same,
but now COG will travel against the heel side.



So the heads position and loft can be constant, and AOA variable, just like Face angle can be variable to a constant path or opposite.

Edited March 17, 2023 by Howard_Jones

[ezra76]

5 hours ago, GungHoGolf said:

You’ll need a launch monitor to tell you your dynamic loft. What monitor are you using that tells you AoA but not dynamic loft?

 

 

Trackman

[GungHoGolf]

17 hours ago, ezra76 said:

Trackman

TM measures dynamic loft. Perhaps you didn’t have that data tile displayed?

[Stuart_G]

On 3/17/2023 at 1:17 PM, Howard_Jones said:

Why the same dynamic loft?
Dynamic loft is a product of static loft and shaft bending,

 

And the amount of shaft lean due to release timing and positioning of the body at impact relative to the ball.

 

On 3/17/2023 at 1:17 PM, Howard_Jones said:

and the same player load a release the shaft about the same every time, so "all else equal"dynamic loft will be a value we can use as a constant.

 

If we shall assume that more forward or higher tee = more positiv AOA and always will change dynamic loft (higher), then we are making a bit to many assumptions when the task was to isolate AOA itself, and the influence it has for a 100 MPH player. 

 

 

In a theoretical sense I'm not really disagreeing.  Yes it is important to isolate the AoA and to make some assumptions.   I also agree with the bottom line message you're trying to make.   

 

But it's also important to point out that the reality is that most ams can not control the AoA independent of dynamic loft in their swing.   The more common attempt to manipulate AoA is to change body position relative to the ball - or tee height - in which case the amount of shaft lean - and the dynamic loft can and frequently does change right along with AoA.   Only much better players tend to be able to isolate AoA somewhat independent of dynamic loft.

 

But this isn't a criticism of the post or the message.  IMO this is an important additional argument NOT to try and change AoA.   Because - in addition to not really being much of a factor in the theoretical sense - it can also introduce many other problems into the swing and the ball flight results.   Added dynamic loft for even higher  spin, poor face impact location, even effect consistency and shot shape control.

 

 

 

Edited March 19, 2023 by Stuart_G

[nkurz]

On 3/17/2023 at 3:07 PM, Howard_Jones said:

SPIN loft comes up short real life, we will not be able to use it to explain spin

 

Could you expand on what you mean by this?  Do you say this because measurement errors make Spin Loft difficult to use to calculate actual spin?  Because other hard to measure factors like impact position (and hence gear effect) can overwhelm it?  Or something else?  

 

2 hours ago, Stuart_G said:

Because - in addition to not really being much of a factor in the theoretical sense - it can also introduce many other problems into the swing and the ball flight results.

 

While there might be good reasons not to change AOA, I don't understand the argument that it's not much of a factor.  To me, it seems like it's one of the biggest factors!   I think the difference in answer comes down to how closely related to Launch Angle you think it is.   We do agree that Launch Angle is important and worth optimizing, right?  

 

Howard thinks AOA doesn't have much effect on Launch Angle because he's thinks it's mathematically simpler to keep Dynamic Loft fixed.  I, relying on a more physical model, think it's better to assume that Dynamic Loft and AOA are intimately connected.  I believe that if you start with a delofted swing then move the ball forward and make contact after the low point, the ball will go higher with almost no change in spin.  

 

Putting some numbers on it, assume a 100 mph swingspeed golfer with a 10 degree driver and 0 AOA.  They'll get something like 150 mph ball speed with a 9 degree Launch Angle and 2500 rpm of backspin.  Flightscope says this yields about 230 of carry (243 including roll).  

 

If (and I do mean if) they could increase their Launch angle to 14 degrees without increasing spin, they'd be at 244 of carry (252 including roll).   At almost more 15 yards of carry and 10 yards of total,  this is a bigger gain than they could get from most other changes, and thus probably worth pursuing if if it can be down without a hurting consistency.    It's the consistency argument that I find harder to discard.  For me it seems to work, but maybe at higher levels of mastery there is something makes this swing harder to control.  

 

Anyway, I think the actual point of dispute is whether it's possible to use AOA to increase Launch Angle without changing spin.  In Howard's model where the club face remains pointed in the same direction, it is not, or at least not practical for a 5 degree change.  In my model where one hits the ball on the upswing, I think it's quite possible, at least for a golfer who is willing to practice.  This seems like it should be fairly easy to resolve:  if you tee it high and forward, does it fly higher or not?  Does the spin increase or stay constant?  

 

A separate question, and where I think Howard is doing a excellent service to the world in spreading the word, is whether hitting higher on the face and taking advantage of gear effect might be a better way for many golfers to achieve a high launch angle at low spin rates.   Absolutely!  But I just think this can be in addition to positive AOA, instead of a being strictly better.   There are limits to how high above COG you can hit while keeping high Smash Factor, and using both lets high swing speed players optimize a little better.  

 

 

 

 

 

[vernon]

🤯

[Stuart_G]

4 hours ago, nkurz said:

Absolutely!  But I just think this can be in addition to positive AOA, instead of a being strictly better.   There are limits to how high above COG you can hit while keeping high Smash Factor, and using both lets high swing speed players optimize a little better. 

 

I'll let Howard answer most of the questions but I will say that IMO - changing AoA should ALWAYS be a decision that's made with the advice and help of a qualified/professional swing instructor.   It should never be a recommendation just for the sake of optimization - and never a recommendation that a fitter should make.

[Howard_Jones]

6 hours ago, nkurz said:

 

Could you expand on what you mean by this?  Do you say this because measurement errors make Spin Loft difficult to use to calculate actual spin?  Because other hard to measure factors like impact position (and hence gear effect) can overwhelm it?  Or something else?  

 

We need a GOOD Robot to be able to get a impact tight enough, but we are not Robots, so all those LM reports ive looked deeper into, from better players with a rather tight impact pattern and smash factor, we are NOT able to see a system for SPIN vs SPIN LOFT, they simply DONT follow each other.
The reason is because vertical gear effects is the absolute strongest, and so strong that 1/8" off will overrule Spin loft many times.

Here is a report of RORY from 2010, analysed so we can see if there is a system to it.
The full report first


Then we enter those numbers into Excel so we can see what we got.
Higher spin loft should mean higher spin right? - NOT

Look at LINE 2 (shot 10) and LINE 3 (shot 8).
Its the only shots above 3000 rpm, but spin loft "rank" is 2 and 3, so they should have been among the 3 lowest spinning, but are the 2 highest of 13
LINE 10 (shot 9) has only 2446 spin, with a spin loft of 12.4*, so why has shot 10 3.039 rpm with a spin loft of only 7.4
 





 

[nkurz]

1 hour ago, Howard_Jones said:

The reason is because vertical gear effects is the absolute strongest, and so strong that 1/8" off will overrule Spin loft many times.

 

Got it.  That makes sense to me, and I agree, although it also seems possible that measurement inaccuracy of the Spin Loft might be playing a big role.  It seems really suspicious that a pro with a grooved driver swing would have a Spin Loft that varies from 5.8 to 13.8 over 10 swings unless they were playing around with new things or switching clubs.  

 

Still, it's hard to understand where there is still (apparently) so little emphasis on impact position relative to other factors.  I happened to be (re?) reading  Tom Wishon's "Search for the Perfect Golf Club" and I was startled by how dismissive he was of vertical gear effect.  It's completely the opposite of your statement.  Here's a quote (P. 31-32): 

 

Quote

And yes, I know of the so-called vertical gear effect that can change backspin from the effect of a high or low shot on the face, which I can assure you is not even close to enough spin change to cause any visible alteration in the flight of the ball.

 

One might hope he was talking only about irons, where this is at least closer to true, but it's right under a diagram of horizontal gear effect on a modern metal wood.  This was published in 2005, so there definitely were some decent launch monitors around, but maybe they weren't accurately measuring spin yet?   A lot of his approaches have held up well, but he seems to have really gotten the wrong end of the stick here.  

 

[Howard_Jones]

18 hours ago, nkurz said:

While there might be good reasons not to change AOA, I don't understand the argument that it's not much of a factor.  To me, it seems like it's one of the biggest factors!   I think the difference in answer comes down to how closely related to Launch Angle you think it is.   We do agree that Launch Angle is important and worth optimizing, right?  

 

 

Absolutely yes, and we do that by dailing in a good impact area, then we can judge the need for loft to get the ball slight we want

 

 

18 hours ago, nkurz said:

 

Howard thinks AOA doesn't have much effect on Launch Angle because he's thinks it's mathematically simpler to keep Dynamic Loft fixed.  I, relying on a more physical model, think it's better to assume that Dynamic Loft and AOA are intimately connected.  I believe that if you start with a delofted swing then move the ball forward and make contact after the low point, the ball will go higher with almost no change in spin.  

 

Dont think of the swing like its 2 D, its not
We might think that when the swing is at the bottom, and the club head goes up again, we have a positive AOA, and thats correct, but it does not mean the club was delofted on the way don, or have added loft on its way up. All specs is related, but independent.
But YES, if you chaneg AOA into positive, launch goes up due to a better "exchange rate" drom dynamic loft to launch angle, but thats not much...see below
 

18 hours ago, nkurz said:

Putting some numbers on it, assume a 100 mph swingspeed golfer with a 10 degree driver and 0 AOA.  They'll get something like 150 mph ball speed with a 9 degree Launch Angle and 2500 rpm of backspin.  Flightscope says this yields about 230 of carry (243 including roll).

If (and I do mean if) they could increase their Launch angle to 14 degrees without increasing spin, they'd be at 244 of carry (252 including roll).   At almost more 15 yards of carry and 10 yards of total,  this is a bigger gain than they could get from most other changes, and thus probably worth pursuing if if it can be down without a hurting consistency.    It's the consistency argument that I find harder to discard.  For me it seems to work, but maybe at higher levels of mastery there is something makes this swing harder to control.  

 

Thats mission impossible, just look at the numbers.

AOA - 0 TO PLUS 5

Launch of only 9  at 0 AOA has a ratio to AOA 0f 0.85
9 / 0.85 = 10.6 Dynamic loft.

Thats our starting point, now we want the same player to alter his swing (we use +5), and tagret launch is 14, who gives this number
14 / 0.91 (the ratio at +5*) = 15.38 Dynamic loft needed

Target 15.38 Dynamic loft
Now 10.6 Dynamic loft
= 4.78* of extra loft needed to get to target.
(Club loft goes from 10 to 14.78 as example)

MINUS 5 to PLUS 5
Even the extreme case, where hIs launch was due to -5.0* to AOA we get impossible numbers
A launch angle of only 9, with -5* AOA have a ratio of 0.768 to Dynamic loft
9 / 0.768 = 11.7 Dynamic loft

Now we alter hos swing from minus 5 to plus 5.
0.91 x 11.7 = 10.64 as launch angle

A change of AOA with 10, all else equal, changed launch angle 1.64*, but we demanded 5*, so that cant be done with a change of AOA only, we have to improve something else too.

A change of 1.64* to launch angle makes little to no difference of importance, we gain or loose way more with a tight vs variable impact pattern

6.3 yards carry gained from a AOA change of 10..... 






9 

Edited March 20, 2023 by Howard_Jones

[Howard_Jones]

18 hours ago, nkurz said:

Anyway, I think the actual point of dispute is whether it's possible to use AOA to increase Launch Angle without changing spin.  In Howard's model where the club face remains pointed in the same direction, it is not, or at least not practical for a 5 degree change.  In my model where one hits the ball on the upswing, I think it's quite possible, at least for a golfer who is willing to practice.  This seems like it should be fairly easy to resolve:  if you tee it high and forward, does it fly higher or not?  Does the spin increase or stay constant?  

 

How many times to i have to show you the gear ratio DL to launch?
Improved AOA = more launch from the same dynamic loft
In the example give above, a change of AOA with 10 changes launch with 1.64* when we isolate it.

 

18 hours ago, nkurz said:

A separate question, and where I think Howard is doing a excellent service to the world in spreading the word, is whether hitting higher on the face and taking advantage of gear effect might be a better way for many golfers to achieve a high launch angle at low spin rates.   Absolutely!  But I just think this can be in addition to positive AOA, instead of a being strictly better.   There are limits to how high above COG you can hit while keeping high Smash Factor, and using both lets high swing speed players optimize a little better.  

For me, SW values during fitting, or AOA thinking is useless.
If you follow my DIY driver tune up, you will on the way, find what works for you and your swing
If the swing by that changes and add dynamic loft when needed, FINE, but focus on IMPACT position, since thats where BALL SPEED , LAUNCH ANGLE & SPIN values is dictated from
ALL the 3 key parameters is ruled by IMPACT position.

When found, use loft up or down to tweak ball flight.

COMPARED
A realistic possible change of AOA for most players is limited to 5*
Depending on what Dynamic loft and club speed we have, a change of 5* will still be BELOW 1.0* for launch angle.

If we move impact 3/8" on the face, launch goes up by 1.0* (more than a change of 5 to AOA), and we cut 720 rpm spin at the same time, while a change to AOA only changed launch, spin  remained the same.

Its no doubt about where our focus should be, whats important and whats not
 


 

[Howard_Jones]

I looked into some of my notes to see if there was some reports who could indicated that Dynamic loft goes up with a positive AOA, and down with a negative, and YES, i found at least 1 who support that, but before we make any conclusions we should see more reports than only 1.

This is a analyze of numbers from Adam Young, where he tries to deliver the club with max positive vs max negative AOA. The first box where Positive and Negative AOA is where we can see it.

When his AOA is average + 5.8*, his average Dynamic loft is 15.44*
When his AOA is average - 5.2*, his average Dynamic loft is 9.16*
Difference is 11 to AOA and 6.27 to Dyn Loft

In this case, Dynamic loft goes op with 0.57* average for each 1 change of AOA
0.57 added DL x 091 = 0.51* added launch

Again we can see that thats is no system what so ever to SPIN vs SPIN loft, we we ca NOT say that AOA makes a difference to spin, it makes a difference to LAUNCH angle, since we get a better "exchange rate" from Dynamic loft to launch, and MAYBE a positive AOA always has a trend where we get some added dynamic loft on the bargain.

But, we can still hit up with 5*, and make impact low and heel side....so focus has to be on IMPACT and the swing we got.

Edited March 20, 2023 by Howard_Jones

[Howard_Jones]

Lets try your case impossible, and add in Adam Youngs numbers for AOA to DL
To make it right, and give you the benefit of a higher DL as start, we say those numbers was from -5.0 in stead of 0 as AOA

Starting point
150 Ball speed - 9 Launch - 2500 Spin - AOA -5.0 
9 / 0.768 = 11.71 Dynamic loft.

Target
14 launch who needs 14 / 0.91 = 15.38 Dynamic loft.

Needed Dynamic loft = 15.38* - 11.71* = 3.67*
Using Adam Youngs numbers for added DL vs AOA og 0.57 we get this

3.67 / 0.57 = 6.43* as change to AOA.....

That want bring us all the way, since we are not up where we get the best exchange rate from Dynamic loft to launch, we have only moved from -5 to +1.43*, and the exchange rate to launch is only 0.866

15.38* Dynamic loft x 0.866 = 13.31* launch...target is 14

So it seems like if we can move AOA from minus 5 to plus 2-3 or by about 7 - 7.5*, your scenario is possible, and your 13 yards found at Flightscope can be found.....

BUT, THIS chart will still be the valid one when we shall judge AOAs influence on launch since its all about LAUNCH ANGLE wanted, and by that, a certain Dynamic loft needed, vs AOA





AOA changes compared to the variable we see to impact should make it clear where focus should be, or start. We will NOT improve our game with a different AOA, without a tight good impact pattern, so at least establish that first by club tweaks to make it fit you.

THEN you might look into what swing tweaks can deliver, and you have a club you can handle, and the very best odds to make those changes.

Impacts influence alone:, no matter AOA...
And its UNDERESTIMATED, since high to low ball speed is ONLY 3 mph (151 down to 148), and thats the GOOD area...what if your smash is average below 1.45, and you loose 6 mph ball speed vs max, not only 3 as illustrated?

 

Flightscope is tuning their algorithms often, so when i enter the datas from the best shot above, 151 Ball speed, 15 launch and 2050 RPM it delivers
248.9 yards carry and potentially 275.1 total (hard fairway)

If we now goes to the BLUE DOT, and use the same launch and spin values from gear effects with 3.450 rpm spin and 13 launch, but reduces ball speed to a smash of 1.43 instead of 1.48, we get 143 mph ball speed (not unusual, the Blue dot moves on the same height and heel side to the 97 mph club speed line, its now on the 99 mph line so its only 0.5 inch heel side vs now)

Those input values returns
223.7 yards carry and a potentially total of 242.4

248.9 vs 223.7 = 25.2 yards on carry
275.1 vs 242.4 = 28.7 yards on total

His carry can be improved to a distance 6.5 yards longer than his total was, ONLY by improved impact position alone. This was on a FAST rolling fairway.

If its was a medium fairway, his Total WAS only 229.4, and then a new carry of 248.9 really makes a difference when its almost 20 yards longer, now as CARRY. With a MID rolling fairway new total will be 258 or 28.6 yards more 

Thats inline with many feedback from several players claiming they gained 30 yards or more by tuning up their own driver by using my DIY driver tune up.
 

Edited March 20, 2023 by Howard_Jones

[Howard_Jones]

This is a edited version of the chart above.
Since we gain or loose launch angle vs AOA, the difference is the need for DYNAMIC LOFT
The 100 mph player should seek a launch from 13 as minimum - 17 as maximum

If he has a POSITIVE AOA of 5, he belongs to the GREEN FIELD for Dynamic loft need (14-19)
If he has a NEGATIVE AOA of 5, he belongs to the RED FIELD and need 17-23 Dynamic loft to get to the same launch angle.

14 Dynamic loft vs 17 as need = 3 more loft needed to get to the same launch
9* vs 12* heads to get to the same launch angle

SIMPLIFIED LOFT CHOICE VS AOA
- AOA = +5* = 9* Loft
- AOA = 0* = 10.5* Loft
 -AOA = -5* = 12* Loft

That will bring them all to about the same launch angle.

So, when we have a player, and his average AOA, we can do the math for how much more loft he needs to get to the launch angle we want. Thats how we use this.
 

 

if we use a FIXED factor where 4* of loft is always added by the shaft or swing, we can make a map for LOFT and launch angle like this.
Now it should be easy to pick the right loft, vs wanted launch and actual AOA as average.

 

Edited March 20, 2023 by Howard_Jones

[Howard_Jones]

Ive made a edit to the main post, where the concution is
- A player with a negative AOA of -5.0* need 1.5* extra loft to get to the same launch angle as a player with 0* AOA, so for Negative AOA. 1.5* loft compensate for 5.0* as AOA
- A player with 0* AOA, needs only 1.0 extra loft to get to the same launch as the player with a AOA of plus 5.0*

The "cost" as spin to get there can be found in this "price list"
- Negative AOA -5.0* need 1.5* static loft to get to the Launch angle of 0* AOA, at 100 mph that cost 390 rpm.
- Each 1.0 to AOA into negative cost average 390 / 5 = 78 RPM (saved or lost)

From 0* AOA to the launch of +5.0* AOA we only need 1.0* extra loft who cost 260 Rpm spin. Each 1.0 to AOA into positive saves 260 /5 = 52 rpm average



The extreme case is the player with negative AOA of -5.0*
He needs 2.5* loft to get to the same launch as the player with ¨5.0* AOA and at 100 mph, that cost 650 rpm of spin.

If we take advantage of vertical gear effects, and use the same formula where 1/8" = 240 rpm or 1/16 = 120, the additional spin of 650, can be cut of by moving impact 5/16 higher
5 x 120 = 600 Rpm cut of. (less than 3/8" higher, at 3/8" up spin cut off would have been 720 rpm)

For MOST players, we have a scenario of 1 or 1.5 extra loft to get the same LA as the AOA +5* player", so the "extra" spin it takes, is most often 260 to 390 Rpm by loft changes, and that only take about 1/8" (240 rpm) to 3/16" (360 rpm) higher impact needed, to "equalize".

So IMPACT position remains the most important, just use what ever loft it takes to get launch right,a d make sure your driver fits you in the first place.

THE LOFT SYSTEM IN GROUPS
The GREEN Fields indicate the closest Launch angle
The rule of thumbs for LOFT vs AOA is very good.

Edited March 20, 2023 by Howard_Jones

[Howard_Jones]

Knowing this, we can now plug in some numbers and compare our 3 players

Player 1 has a POSITIVE AOA of 5* and (ex) a 9.0* loft
Ball speed 150 - Spin 2050 - Launch 15
Carry 246 - Potential total hard fairway 273.8

Player 2 has a NEUTRAL AOA of 0* and a head (ex) 10* loft
Ball speed 150 - Spin 2310  (plus 260 from 1.0 loft)- Launch 15
Carry 245.9 - Potential total hard fairway 270.4

Player 3 has a NEGATIVE AOA of -5*and a head (ex) of 11.5*
Ball speed 150 - Spin 2700 (plus 650 from 2.5 loft)- Launch 15
Carry 244 - Potential total hard fairway 265.2 

What happens if we manage to BOOST the -5* player to the max, taking advantage of VCOG like i show off in my DIY driver tune up?

If we move his impact 2/8" up, and 3/8" toe side, he gains 0.7* on launch, and cut of 480 rpm of spin. New numbers : Ball speed 152 - Spin 2700 - 480 = 2220 - launch 15.7*. Carry 251.3 yards, potential carry on a hard fairway 275.7 yards

As long as LOFT is fittet CORRECT, we can get to the optimum for launch, and by that carry, even from negative AOA. its TOTAL that will suffer a little from higher spin, but a tuned up club and a tight impact pattern, makes it all a NO Brainer, USE LOFT to get launch angle right, and never mind AOA.


 

Edited March 20, 2023 by Howard_Jones

[nkurz]

Thanks Howard for your detailed responses.  I didn't have time to think about them adequately today to respond---hopefully tomorrow.  I thought they deserved better than a quick response, but didn't have time to do them justice.  If anyone else wants to jump in with thoughts before I do, please go ahead!

[fjk]

4 hours ago, nkurz said:

Thanks Howard for your detailed responses.  I didn't have time to think about them adequately today to respond---hopefully tomorrow.  I thought they deserved better than a quick response, but didn't have time to do them justice.  If anyone else wants to jump in with thoughts before I do, please go ahead!

I think the same way as you and had the same question.
 

Maybe one assumption you are making is that the center of the swing is fixed so  that by moving ball position from -5 AOA to +5AOA you’ll get the same change as if the club were a hand on a clock face. 
 

In addition to shaft lean and release as Stuart mentioned, the club isn’t moving on a fixed circular arc at the bottom of the swing where you can assume changes to AOA are 1:1 with delivered loft? The handle is moving forward as the club is released from downward AOA to upward AOA. So there must be some rise to the club that affects AOA and not just pivot from the handle. 

Edited March 21, 2023 by fjk

[Howard_Jones]

17 hours ago, nkurz said:

Thanks Howard for your detailed responses.  I didn't have time to think about them adequately today to respond---hopefully tomorrow.  I thought they deserved better than a quick response, but didn't have time to do them justice.  If anyone else wants to jump in with thoughts before I do, please go ahead!

Hmmmm. 

YOU ARE ON TO SOMETHING.....THANKS FOR INPUT

I gave your input about a swing change against a positive AOA some thinking and i could not help it, i had to make a excel calculator to debunk myself or your claims.

ISOLATED, AOA only changes our gear ratio from dynamic loft to launch.
But, changing our swing against a positive AOA, DOES have a potential, and if we look at the photo of Bobby Jones, we get "picture" of it.



It boils down to, HOW FAST FORWARD is our hands right before impact?

- If out hands STOPPED when our arms was where the bottom of the swing is, the clubs point of rotation would be the butt end, and since we was at the bottom, 1 * "forward" for the head, would add 1.0* of loft. I would call that "flipping hands".

The extreme opposite is the player where his hands is just as fast as the club head, he can even DELOFT the club, and have a positive AOA, since his arm will lift the club up, and by that move COG upwards,

.


The slow hands will give a ratio UP against 1.0, but they have to stop to get there, and the fast hands down against zero.

The average and "truth" would be something like "medium fast", and maybe in the area we saw in the case of Adam Young.

Its simply so many parameters that makes its own influence here, it would be hard to set a average factor without tons of data, but i used Adam Youngs numbers who said 1* AOA into plus, ALSO adds 0.57* of Dynamic loft

Ive only done the numbers for launch, and compared the "isolated to AOA" scenario vs the "Adam Young Scenario" where added dynamic loft adds another difference to launch, not only the influence from the gear ratio itself

11 players with a difference to AOA of 1.0* in a realistic launch area for 100 mph



Now we adjust for the "Adam Young factor" and say 0* AOA is point zero
When we go into positive AOA, we gain 0.57 Dynamic loft for each 1.0* on AOA. When we go into negative AOA, we loose 0.57 Dynamic loft for each 1.0* on AOA

That brings launch angle to 7* apart (it was 2.2* cause by AOA alone), so there is something to it, ill get back with more numbers later, this was kind of interesting, at least of academical interest.


it DOES make a difference, even if the hands is so fast, it only changes DL with 0.2* for each 1* to AOA.

Edited March 21, 2023 by Howard_Jones

[Stuart_G]

19 minutes ago, Howard_Jones said:

It boils down to, HOW FAST FORWARD is our hands right before impact?

 

Close - but not really.

 

19 minutes ago, Howard_Jones said:

- If out hands STOPPED when our arms was where the bottom of the swing is, the clubs point of rotation would be the butt end, and since we was at the bottom, 1 * "forward" for the head, would add 1.0* of loft.

The extreme opposite is the player where his hands is just as fast as the club head, he can even DELOFT the club, and have a positive AOA, since his arm will lift the club up, and by that move COG upwards,
 

 

Hands always stall for the release and will always be WAY slower than the club head speed at impact.  Plenty of data to support that if you want to dig around for it.

 

The difference is actually in the release timing - or more specifically where the hands end up at impact - not how fast they are going.    That will determine how much (if any) the upward motion of the hands (from the arc the hands swing on) can add to the AoA of the head  as well as how the dynamic loft is effected (amount of shaft lean).

 

[Howard_Jones]

7 minutes ago, Stuart_G said:

 

Close - but not really.

 

 

Hands always stall for the release and will always be WAY slower than the club head speed at impact.  Plenty of data to support that if you want to dig around for it.

 

The difference is actually in the release timing - or more specifically where the hands end up at impact - not how fast they are going.    That will determine how much (if any) the upward motion of the hands (from the arc the hands swing on) can add to the AoA of the head  as well as how the dynamic loft is effected (amount of shaft lean).

 

It seems to be within 0 to 1.0* somewhere, and i should have had access to way more LM reports to see if there was "better trends", but now i made 3 examples, thew first with no influence, ( (super-fast hands), the others fast to medium, so "pick one"....i dont know whats closest to the average realitý here.

Nkurz was on to something. I did not look for that, but to isolate the effect of AOA (as launch, loft needed to compensate, AOAs influence as lost or gained spin, and at last, distance), but this input made it all more interesting.

Edited March 21, 2023 by Howard_Jones