The Stack System

[birdiestobogeys]

14 hours ago, lookylookitzadam said:

Did they make mention to requirements for it? I heard about it on a podcast as well and it sounds like it will be a wedge combine, so that’s exciting!  I heard the catch is you have to use the Stacks branded PRGR launch monitor. 

I didn’t hear mention of that. I have a stack radar so that works for me. Here is the video. 

 

[RCGA]

Isn't the Stack radar just a PRGR with bluetooth? If so, there is no way it's accurate enough to give you any statistically viable information. 

 

Edit: This is in relation to the new wedge app 

Edited February 12 by RCGA

[NosajNeelik]

3 hours ago, RCGA said:

Isn't the Stack radar just a PRGR with bluetooth? If so, there is no way it's accurate enough to give you any statistically viable information. 

Except it is so….

[birdiestobogeys]

4 hours ago, RCGA said:

Isn't the Stack radar just a PRGR with bluetooth? If so, there is no way it's accurate enough to give you any statistically viable information. 

 

Edit: This is in relation to the new wedge app 

the claim is that carry distance up to 150 yards can mostly be predicted by ball speed. Yes, the prgr is only ball speed and club head speed, but I was under the impression it was very accurate with those two figures. Maybe I was mistaken. 

[RCGA]

15 minutes ago, birdiestobogeys said:

the claim is that carry distance up to 150 yards can mostly be predicted by ball speed. Yes, the prgr is only ball speed and club head speed, but I was under the impression it was very accurate with those two figures. Maybe I was mistaken. 

 

You need spin, ballspeed alone isn't good enough. I'm shocked they're claiming ball speed alone is "99%" accurate. Also, the PRGR is okay, but it's absolutely not good enough to narrow in on 10y gaps with any level of confidence for anyone below a 20hcp. 

 

Ball speed of 80mph and launch of 25* 

Spin at 4800 = 99y carry

Spin at 9000 = 93y carry 

 

Ball speed of 100mph and launch of 25* 

Spin at 4800 = 136y carry

Spin at 9000 = 123y carry 

[birdiestobogeys]

Interesting. Thanks for providing that data. I bought the stack system and radar at the end of last year knowing that wedge mode was coming. It was what tipped the scale in favor of me making the purchase. If I’m hitting my driver longer I would probably have more partial wedge shots that I would need to improve on. 
 

But if their claims are inaccurate that would be disappointing. I’m still hopeful that if you have normal launch and spin conditions it can still be useful for backyard practice. Maybe not up to 150 yards, but those 100 and in ones that I seem to always miss by 10 yards. 

[RCGA]

1 hour ago, birdiestobogeys said:

Interesting. Thanks for providing that data. I bought the stack system and radar at the end of last year knowing that wedge mode was coming. It was what tipped the scale in favor of me making the purchase. If I’m hitting my driver longer I would probably have more partial wedge shots that I would need to improve on. 
 

But if their claims are inaccurate that would be disappointing. I’m still hopeful that if you have normal launch and spin conditions it can still be useful for backyard practice. Maybe not up to 150 yards, but those 100 and in ones that I seem to always miss by 10 yards. 

 

The only way they can do it is if they pre-set the spin and launch numbers based on the shot (ex. 100y shot will always spin at X and launch at Y). But like, you can hit a 100y shot a dozen different ways (high, low, different clubs, etc.) and could probably change spin windows by 2k RPM though club choice, swing and ball. 

 

Don't get me wrong, it'll be fun for a while; I used a PRGR as my only launch monitor for 2 winters. I think it's fine for the swing speed stuff, but leaning on it for granular distance practice is a bit of a stretch. 

 

[NosajNeelik]

5 hours ago, RCGA said:

 

You need spin, ballspeed alone isn't good enough. I'm shocked they're claiming ball speed alone is "99%" accurate. Also, the PRGR is okay, but it's absolutely not good enough to narrow in on 10y gaps with any level of confidence for anyone below a 20hcp. 

 

Ball speed of 80mph and launch of 25* 

Spin at 4800 = 99y carry

Spin at 9000 = 93y carry 

 

Ball speed of 100mph and launch of 25* 

Spin at 4800 = 136y carry

Spin at 9000 = 123y carry 

Nobody is spinning an 80 yard wedge 4800 rpm 

[dcmidnight]

8 hours ago, NosajNeelik said:

Nobody is spinning an 80 yard wedge 4800 rpm 

 

And everyone is going to launch it differently as well. I think the point is there are just too many variables - that can provide a huge range of distances - to do this at the level they are claiming. If we used say the Flightscope optimizer and played with the launch angle, holding swing speed constant, my guess is you could spread that out pretty good.

 

Personally I thought their radar version was worth the upgrade simply because it auto reads the swing. But I would never think about using it at the range for anything other than swing speed.

 

And...yeah, if any other brand of $200 unit was claiming something like this, I would probably be crushing them.

[NosajNeelik]

3 hours ago, dcmidnight said:

 

And everyone is going to launch it differently as well. I think the point is there are just too many variables - that can provide a huge range of distances - to do this at the level they are claiming. If we used say the Flightscope optimizer and played with the launch angle, holding swing speed constant, my guess is you could spread that out pretty good.

 

Personally I thought their radar version was worth the upgrade simply because it auto reads the swing. But I would never think about using it at the range for anything other than swing speed.

 

And...yeah, if any other brand of $200 unit was claiming something like this, I would probably be crushing them.

That’s all good but was just commenting on the fact that no one is realistically going to spin an 80-120 yard shot 4800 rpm so the argument was moot. I mean maybe in a gale force wind downhill you would putt it but that’s not what’s we’re talking about.  And honestly the difference in the example were less than ten yards. So if a high handicap can consistently hit a wedge with ten yards of his target that’s an incredible improvement generally. 

Edited February 13 by NosajNeelik

[OHGolfer2]

I saw on twitter that the Stack Wedge will initially only work with the Stack radar, but then, a month or so after its release, it'll work with other LMs.  Presumably, they'll allow you to manually enter a carry distance from whatever LM you're using.  This would seem to be the best of both worlds - you'll get the feedback from the Stack app about your wedge strengths/weaknesses, while also getting carry data from a LM that is more accurate than the PRGR.  

[RCGA]

12 hours ago, NosajNeelik said:

Nobody is spinning an 80 yard wedge 4800 rpm 

I'm not saying an 80y wedge carry. I'm saying a ball speed of 80mph. 

 

My argument is that without accurate measured spin data, you're just guessing carry; that's why no one takes these low end radar units seriously. 

 

There was also a comment about this being okay for high handicap golfers. Higher handicaps have worse consistently over launch and spin (and strike), causing more issues with predicting distance patterns using just ball speed. 

[NosajNeelik]

22 minutes ago, RCGA said:

I'm not saying an 80y wedge carry. I'm saying a ball speed of 80mph. 

 

My argument is that without accurate measured spin data, you're just guessing carry; that's why no one takes these low end radar units seriously. 

 

There was also a comment about this being okay for high handicap golfers. Higher handicaps have worse consistently over launch and spin (and strike), causing more issues with predicting distance patterns using just ball speed. 

Ok well no is spinning a 99 yard shot 4800 so it’s still isn’t relevant. 
 

I totally disagree with your last point that if these can help a higher handicap get a consistent ball speed with a swing speed then that means they are improving their strike. Not everyone can buy a 2000-25000 dollar launch monitor. 

[dcmidnight]

8 minutes ago, NosajNeelik said:

Ok well no is spinning a 99 yard shot 4800 so it’s still isn’t relevant. 
 

I totally disagree with your last point that if these can help a higher handicap get a consistent ball speed with a swing speed then that means they are improving their strike. Not everyone can buy a 2000-25000 dollar launch monitor. 

 

I dont understand the correlation between consistent swings speed and quality of strike. Simply being consistent in your swing speed doesn't (necessarily) mean anything about your shot quality?

 

But I guess if you are that high a handicap - do you need any launch monitor at all?

 

Go to the range and point yourself at a 100 yard flag. Shouldnt be hard to determine your consistency and if you are getting better or worse.

[iacas]

1 hour ago, RCGA said:

My argument is that without accurate measured spin data, you're just guessing carry; that's why no one takes these low end radar units seriously.

 

I'm not going to argue that the low-end units are as good as a QuadMAX.

 

I am going to say that, in my testing, they're at least fairly consistent among themselves. If you swing a driver on a cheaper radar unit and it says 104, but your QuadMAX says 106.8… and your next swing is 103, and then 104, and then 103, and then 102… you can be pretty sure the QM is going to say something like 105.7, 106.7, 105.5, 104.9… etc.

 

They're reasonably precise, even if they're not super accurate and precise.

 

You started the topic with a disingenuous comparison between a normal amount of spin and a ridiculous amount of spin. So let's discard that and narrow the range to a smaller set of values:

 

A ball hit 65 MPH at 28° carries 67.3 yards at 8000 RPM and 68.9 at 10,000 RPM.

 

That's a pretty tight window, more than tight enough for a 10 handicapper to practice wedges in a controlled AI-driven way. And if they're bad, and launch it at 35° with 7000 and 9000 RPM spin, we get 68.7 and 66.6.

 

So, I think ball speed is more than "decent" for helping people manage their distances.

 

Heck, sometimes it can be better: imagine a launch monitor and a speed radar asking someone to hit a ball 68.7 yards or 65 MPH. On a launch monitor, they might blade it badly and it might even fly 68.7 yards, but the speed radar would likely measure a higher smash factor and a much higher ball speed than 65, so they'd fail.

 

You'll also note I varied the launch angle and spin across those four data points, and yet the widest numbers were 66.6 and 68.9. IMO that's pretty good for a pretty good chunk of the population, who can use their radar and get more out of it.

 

And if you have a QuadMAX, just use that instead. Or use both together.

 

1 hour ago, RCGA said:

My argument is that without accurate measured spin data, you're just guessing carry; that's why no one takes these low end radar units seriously. 

 

AFAIK the Stack wedge stuff isn't guessing carry. It's just asking you to hit ball speeds, which correlate to a fairly consistent carry yardage.

 

1 hour ago, RCGA said:

There was also a comment about this being okay for high handicap golfers. Higher handicaps have worse consistently over launch and spin (and strike), causing more issues with predicting distance patterns using just ball speed. 

 

And yet… still a pretty narrow window, and if they're measuring ball speed, my example above shows how it may even be better for them.

[NosajNeelik]

1 hour ago, dcmidnight said:

 

I dont understand the correlation between consistent swings speed and quality of strike. Simply being consistent in your swing speed doesn't (necessarily) mean anything about your shot quality?

 

But I guess if you are that high a handicap - do you need any launch monitor at all?

 

Go to the range and point yourself at a 100 yard flag. Shouldnt be hard to determine your consistency and if you are getting better or worse.

I’m not a high handicap and that’s how I learned my wedge game. I’m saying g if you can get a consistent ball speed with a certain swing speed then your strike is getting better/more consistent because your smash factor improves 

[iacas]

@RCGA, it turns out that this is also one of the situations where the theoretical is outshown by the empirical… because when we consider the theoretical, we have to simplify everything.

 

To wit… a reasonably well hit ball that launches at 65 MPH will go about the same distance whether it's hit with a 7I by a junior golfer or a lob wedge by a +3.

 

I remember years ago people were noodling around with an "ideal smash factor" of 1.0 and then clubhead speed =ball speed = yardage carry for short game shots.

 

I talked briefly with Dr. M and… the long story short is that they tested this against Trackman in normalized mode, and found that they are within 2 yards 95% of the time. Ball speed predicts, empirically, 99% of carry distance from 30 to 150 yards (!!!). Some of that two yards is Trackman error, too.

 

Marty doesn't even get his Trackman out anymore for wedge distances: he uses their radar as it's easier to set up and integrates with their app. The data is just as good, and here's the kicker: unless you're hitting identical golf balls and there are NO changes to the wind or conditions, ball speed may actually be a better predictor than actual measured carry yardage. If your Pro V1 or range ball has some worn dimples or weighs a little bit differently due to absorbing a little more moisture than the last ball you hit, that's two yards. If you get a puff of wind you don't even feel 20 feet off the ground, there's three yards. So, turns out, ball speed may actually be a better predictor.

[birdiestobogeys]

Good discussion here. Funny that we are critiquing a product that isn’t even available yet! Stack just needs to release it already and then the real fun begins. 

[OHGolfer2]

1 hour ago, iacas said:

@RCGA, it turns out that this is also one of the situations where the theoretical is outshown by the empirical… because when we consider the theoretical, we have to simplify everything.

 

To wit… a reasonably well hit ball that launches at 65 MPH will go about the same distance whether it's hit with a 7I by a junior golfer or a lob wedge by a +3.

 

I remember years ago people were noodling around with an "ideal smash factor" of 1.0 and then clubhead speed =ball speed = yardage carry for short game shots.

 

I talked briefly with Dr. M and… the long story short is that they tested this against Trackman in normalized mode, and found that they are within 2 yards 95% of the time. Ball speed predicts, empirically, 99% of carry distance from 30 to 150 yards (!!!). Some of that two yards is Trackman error, too.

 

Marty doesn't even get his Trackman out anymore for wedge distances: he uses their radar as it's easier to set up and integrates with their app. The data is just as good, and here's the kicker: unless you're hitting identical golf balls and there are NO changes to the wind or conditions, ball speed may actually be a better predictor than actual measured carry yardage. If your Pro V1 or range ball has some worn dimples or weighs a little bit differently due to absorbing a little more moisture than the last ball you hit, that's two yards. If you get a puff of wind you don't even feel 20 feet off the ground, there's three yards. So, turns out, ball speed may actually be a better predictor.

This is excellent info, thank you!

[GolfTurkey]

4 hours ago, iacas said:

 Trackman error

 

Heresy!!

 

As penance, please spend the next week practising hitting 5 degrees up on driver to gain 45 extra yards as per the Trackman chart.

[iacas]

4 hours ago, birdiestobogeys said:

Good discussion here. Funny that we are critiquing a product that isn’t even available yet! Stack just needs to release it already and then the real fun begins. 

 

It came out earlier today. I went through the baseline testing and compared the numbers to my GC and the GSPro ball flight algorithm.

[OHGolfer2]

@iacaswhat did you think of the wedge feature?  I have a regular PRGR (not a stack radar), so I can’t use it.  Wondering if the Stack app gives some good insight? 

[iacas]

11 minutes ago, OHGolfer2 said:

@iacaswhat did you think of the wedge feature?  I have a regular PRGR (not a stack radar), so I can’t use it.  Wondering if the Stack app gives some good insight? 

 

I did the baseline, and the Stack radar driven yardages were within a yard or two of what the GC and GSPro reported each time.

 

I'll do one of the actual tests another day. So far, I'm impressed.

[Rbsiedsc]

16 hours ago, iacas said:

 

It came out earlier today. I went through the baseline testing and compared the numbers to my GC and the GSPro ball flight algorithm.

so is it possible to use this new feature with a non stack radar?

[iacas]

2 hours ago, Rbsiedsc said:

so is it possible to use this new feature with a non stack radar?

 

No. Not currently.

[RCGA]

Ball speed predicts distance? 

 

First shot

79.5 BS

5182 RPM

109y carry

 

Second shot

80.8 BS

11,624 RPM (!!!)

99.9y carry

 

And not that it matters, but the difference between the two shots nets out to ~17y. 

 

 

 

Edited February 14 by RCGA

[DLiver]

Not sure why I would need a speed training program to offer a wedge program, but carry on men...

[birdiestobogeys]

1 hour ago, DLiver said:

Not sure why I would need a speed training program to offer a wedge program, but carry on men...

Because you’ll be hitting such big bombs that all you’ll need is a flip wedge in. Makes sense to me. 

[iacas]

1 hour ago, RCGA said:

Ball speed predicts distance? 

 

I shared what I shared above. You've come back with extremely different shots hit on GSPro (i.e. an algorithm, not outside in the real world) on a hole that plays 10% downhill.

 

I think the onus still lies with you to do something more than this. For now, I'm going to trust the PhD who hit and measured thousands of shots outside. Especially when it aligns with my baseline testing yesterday, which was within 2 yards every time on GSPro and my Foresight LM.

 

 

53 minutes ago, DLiver said:

Not sure why I would need a speed training program to offer a wedge program, but carry on men...

 

It has a pretty great putting training feature, too.

[RCGA]

First I'm told ball speed is all that matters....then I show spin has a big impact on distance

 

Next I'm told no one would spin a wedge at 5k RPM....then I show a 100y shot at 5100 RPM finishing 6y from the flag. 

 

Now it's an algorithm, not real world.....okay, you got me there. 

 

And yes, my examples at both ends of the spectrum. I don't disagree that a "normal" wedge shot with a "normal" urethane ball will produce acceptable accuracy with just ball speed. But you can't discount a high handicap in his garage hitting a mixture of urethane and surlyn golf balls, a funky swing off a mat and no reference to what a 100y swing should feel like.