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 Optimize driver carry+roll (total distance) for 73mph CHS « View previous topic :: View next topic » 
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thepinkbomber
PostPosted: Sun Jun 16, 2013 1:49 am    Post subject: Optimize driver carry+roll (total distance) for 73mph CHS Reply with quote

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Joined: 22 May 2013
Posts: 3

Hi,

Love your software. Current user. Actually had email communications with David over the years but sure he doesn't rememember me.

Having trouble and wondering if you can help me. I have a pre-junior. Trying to optimize her driver loft between a 12* or 14*, current is 16* and she hits up on it high but no roll. Maybe you can help having trouble with the details and she has a tournament this week and want to reshaft asap.

Her average club head speed is 73mph. This is average using the swing radar kits you place next to the tee (max higher and min is around 70). Given her age you can assume she doesn't hit it flush all the time so she doesn't get max ~1.49 smash factor but hits it great most of the time. Her face for weight is only 320cc, upgrading to either 400cc or 420cc to get bigger face but still only 185g versus 460cc at 197g.

I haven't measured but her angle of attack is probably ~ 3 degrees up. She clearly is a big hitter up on the ball for last several years. I think this is why for her swing speed I get steered toward higher lofts but she swings up on them so high they go high with little roll (not a popup or hitting down chop). She also has been trained to have an inside to out swing path if that makes a difference. Not sure degree (mine is 6-Cool if I had to guess average 3 degrees in to out.

Looking for max carry with max roll not just max carry which produces less distance than maximizing with roll to. For my swing speed trackman says avg 37* descent gives max total distance but I am finding for slower swings its not 37 degrees.

Can you estimate for 73mph avg CHS with ~ 3 degrees up AoA and average fairway conditions (not soft / not hard) with 3* in to out path what is her maximum carry+roll with 12*, 14* and 16*. Assume they are the lofts on the face versus the number stamped. Her club head weight is 185g not standard 200g adult weight so they may change the calculations slightly.

Any help is appreciated it.

Greatly appreciate the insight!!!!
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thepinkbomber
PostPosted: Sun Jun 16, 2013 1:57 am    Post subject: atmosphere and elevation FYI Reply with quote

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Joined: 22 May 2013
Posts: 3

Forgot to mention I am based out of Philadelphia for atmostphere and elevation estimates. Assume average fairways (not soft and not hard).

Thanks.
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dtutelman
PostPosted: Sun Jun 16, 2013 2:47 am    Post subject: Re: Optimize driver carry+roll (total distance) for 73mph CH Reply with quote

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Joined: 09 Apr 2007
Posts: 105
Location: New Jersey, USA

thepinkbomber wrote:
Having trouble and wondering if you can help me. I have a pre-junior. Trying to optimize her driver loft between a 12* or 14*, current is 16* and she hits up on it high but no roll. Maybe you can help having trouble with the details and she has a tournament this week and want to reshaft asap.

You don't give a guy much time, do you?'Wink'

Quote:
Her average club head speed is 73mph. This is average using the swing radar kits you place next to the tee (max higher and min is around 70). Given her age you can assume she doesn't hit it flush all the time so she doesn't get max ~1.49 smash factor but hits it great most of the time.

Anything less than max smash factor results in a lower ball speed, which requires a higher launch still for maximum carry.

(I'm only going to quote data relevant to your question. Some of the other data is interesting, but we can deal with it another time.)

Quote:
I haven't measured but her angle of attack is probably ~ 3 degrees up. She clearly is a big hitter up on the ball for last several years. I think this is why for her swing speed I get steered toward higher lofts but she swings up on them so high they go high with little roll (not a popup or hitting down chop).

We may have a problem here -- or not, don't know.

You estimate a 3-degree upward AoA. How are you estimating this? If it is because of a cupped wrist at impact, not all of that angle is going into attack. A significant fraction is just increasing the loft at impact. That will indeed give a higher launch angle, but more spin and less ball speed.

It actually takes rather good instrumentation (e.g.- an excellent slow-motion camera, or a Trackman or Flightscope class of launch monitor) to get a good estimate of angle of attack. You could be right. But also, what you and she take for angle of attack could be more loft than is built into the club.

Quote:
She also has been trained to have an inside to out swing path if that makes a difference. Not sure degree... if I had to guess average 3 degrees in to out.

Won't make a lot of difference, maybe a yard of carry, depending on the face angle as well.

Quote:
Looking for max carry with max roll not just max carry which produces less distance than maximizing with roll to...Can you estimate for 73mph avg CHS with ~ 3 degrees up AoA and average fairway conditions (not soft / not hard) with 3* in to out path what is her maximum carry+roll with 12*, 14* and 16*.

As I am sure you have already noted, carry will be maximized for a 16* driver, for the impact parameters you cite. Be aware that this is not just the loft stamped on the club. It is defined as the angle between the clubhead path and the perpendicular to the face at the point of impact. It must include things like loft increase due to cupped wrist, plus about 2* for shaft bend, as well as the effect the club's face roll has when you consider where on the face she hits the ball. (This can be much larger than most people guess; an inch higher or lower on the face is worth 5-6 degrees of loft.)

We have some data for slower swing speeds. TrajectoWare Drive gives pretty good distance estimates there, too -- even lower than hers -- as long as the spin is kept below 4000rpm. (We are working on extending that limit, and hope to have a TrajectoWare version 2 out that can handle higher spins. Not too distant future, we hope.)

We do not have data [yet] for runout after landing. We are studying the problem, but don't have an answer yet. We have some hopes that version 2 will incorporate total distance as well, but are not as close to that answer yet.

Bottom line:

  • I wish I could help compute total distance, but I can't. Not yet anyway.

  • Check to make sure she is not cupping her wrist, and you are not mistaking that for angle of attack. Both will increase the launch angle (a similar amount, but not exactly the same), but they will have very different effects on spin. A cupped wrist will definitely decrease roll after landing, and may also reduce ball speed -- thus both carry and total distance. If that is the problem, then clubfitting will help some, but lessons and practice are the better solution. The clubfitting "band aid" would be reduced loft (to account for the loft she is adding with the cupped wrist), and perhaps length and/or swingweight adjustments to delay her release.


Hope this helps,
DaveT
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thepinkbomber
PostPosted: Sun Jun 16, 2013 4:54 am    Post subject: optimal loft for 73mph swing Reply with quote

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Joined: 22 May 2013
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Good question on AoA. I have been measured by trackman with a large AoA which I have always tought her. I take small tees place them in front of the ball when she soles and makes sure she can swing up over the tee and still hit the ball on a high tee. Can go flat and do it but you can see on high speed video she is going nicely.

She does have a slight cupped wrist at impact but face is square. So far our initial thought is the slight cup wrist at impact is due to a strong grip at address. working on weakening the grip so she can more easily have the back of the left had facing the target which is much easier with a neutral grip versus too strong.

She tends to hit just above center of face so I think what you are saying that increases loft more.

With the high AoA and above center face impact that could be explaining why at 73mph 16* hits a high line drive but then drops with no roll. That is why I was thinking a 14* which is probably more appropriate. I know a friend who has a girl that swings slightly slower than mine and she went to Ping womens club 12*. I tried the ping 16* womens club and she hits it super high so the loft on it probably is 15-17 versus the 14* stamped on in and the 12* they use which I think is too low for 73mp works good because for ping womens its probably a 14* with a 12 stamp on it.

John
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dtutelman
PostPosted: Sun Jun 16, 2013 11:10 am    Post subject: Re: optimal loft for 73mph swing Reply with quote

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Joined: 09 Apr 2007
Posts: 105
Location: New Jersey, USA

thepinkbomber wrote:

Good question on AoA.

...you can see on high speed video she is going nicely. She does have a slight cupped wrist at impact but face is square.

She tends to hit just above center of face so I think what you are saying that increases loft more.

I tried the ping 16* womens club and she hits it super high so the loft on it probably is 15-17 versus the 14* stamped on in and the 12* they use which I think is too low for 73mp works good because for ping womens its probably a 14* with a 12 stamp on it.


OK, we have four possible culprits. (You mentioned three; there's another.) One at a time:

(1) CUPPED WRIST: Probably not a big factor. But any visible angle between the left forearm and the shaft is likely to have some component that is added loft.

(2) IMPACT HIGH ON FACE: This is a GOOD thing. Yes, it will result in a higher ball flight, but the spin is reduced which should help total distance. The magic term is "gear effect". See my articles at http://www.tutelman.com/golf/ballflight/gearEffect2.php and http://www.tutelman.com/golf/ballflight/gearEffect5.php.

(3) VANITY LOFTS: Yes, there is even a term for it. Very common among the OEM manufacturers. Some component companies are also guilty of this, but not nearly as many. Why? Lots of golfers want to think they hit the ball farther than they do. So they get drivers will lower loft (and often stiffer shafts) than they need. The manufacturers have found this so prevalent that they "compensate in advance". The lesson here: measure the loft yourself.

(4) SHAFT BEND: (This is the one you didn't mention.) Shaft bend typically adds 2 degrees to the loft. If you have a tip-flexible (high launch) shaft, it could be more than that.

Think about it. If she has only 1* due to a slightly cupped wrist, add on another 2* due to vanity loft and 2* due to shaft bend, and that brings the 16* driver up to 21* at impact. I didn't even mention face roll and high-face impact; that will increase launch angle but reduce spin, both good for total distance.
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