Dynamic Loft

[deronsizemore]

Can any of you experts out there explain dynamic loft to me and how it's calculated?

I came across this site giving different explanations for terms: http://3jack.blogspot.com/2009/12/trackman-translations-part-iii.html

I can't seem to do the math (never was good at it... ) and get the 11.3° dynamic loft that they get. I assume it has something to do with this part: " adjusted for the impact of the bended shaft (typical +2° for a driver)"

How do you adjust for the impact of a bended shaft for other clubs beside driver?

[sblack5]

dynamic loft is the loft on the face of any given club at impact based on how the club was brought to the ball....be it either ascending or descending.   for instance, my driver is 6.5 * of loft....sitting still.  this is called static loft.  I hit up on the ball 4 to 5 degrees with my driver, meaning at impact the dynamic loft of my driver is 10.5 to 11.5*....which is great launch for my SS.  if I were to come into the ball dead level, my dynamic loft would be 6.5* because I hit the ball with neither an asceending or descending blow.  if I were to hit down on the ball say 2* my dynamic loft would be 4.5* and launch extremely low, and barely leave the ground.  make sense?

works the same in irons too....if a typical 4 iron is 23 degrees, and if you hit down on it 2 degrees, all of the sudden that 4 iron is a 21 degree 4 iron (which is 3 iron territory) and goes as far as a typical 3 iron......that's part of how the tour guys hit their irons so far.

[Beachcomber]

I believe it is pretty simple arithmetic... If you have the tools to give you the base numbers.  The most widely recognized tool - being a Trackman.

Trackman will provide you your Attack Angle (also commonly referred to Angle of Attack or AA) which will be + or - depending on your ascending or descending swing plane... And combine (add) it to your clubs static loft (as sblack5 stated).

Thus if your Attack Angle is +3 (swinging up), and you are playing with a 9* driver... Your Dynamic loft will be ~ 12*.  I use the approximation sign (~) as you also need to take into consideration the amount of lead/lag found in the shaft which is based on the position of the lead arm and shaft angle at impact (P7).

[deronsizemore]

That's exactly thought I thought it was calculated but reading this I'm not sure:

[quote]In the sample we are dealing with, the golfer is hitting a 6-iron which has about 32* of loft. The golfer had a -3.4* attack angle which is about the Tour average and likely had some forward shaft lean.

The result? It took that 6-iron loft and turned it into a 11.3* loft at impact.[/quote]

How do you take a 6 iron with 32* of loft with a -3.4 AOA and get a dynamic loft 11.3*? Like I wrote in my first post, they've got the bit about "adjusting for the impact of a bended shaft" but that doesn't help me figure out how they end up with 11.3* dynamic loft.

[mdl]

That's a typo.  Or the author just has no clue.  There's just no way the face of a 32˚ 6i is 11.3˚ of loft at impact in anything but the punchiest of punch shots.  No fancy math you're missing there.  Perhaps trackman adjusts for average shaft bend at impact given typical flex for a club swung at the seen speed, and that could change things by a couple degrees in addition to the 32˚ loft minus 3.4˚ AoA minus extra forward shaft lean, but what you quoted is just wrong and doesn't make sense.

[saevel25]

Spin Loft = Dynamic Loft - Angle of Attack

Dynamic Loft = Spin Loft + Angle of Attack

Spin loft is determined by the loft of the club, and the dynamics of the shaft at impact. So its really tough to measure, but even if the hands are ahead of the ball at impact, theres no way that there turning a 32 degree club into an 12 degree club on a normal shot.

[deronsizemore]

Originally Posted by mdl

That's a typo.  Or the author just has no clue.  There's just no way the face of a 32˚ 6i is 11.3˚ of loft at impact in anything but the punchiest of punch shots.  No fancy math you're missing there.  Perhaps trackman adjusts for average shaft bend at impact given typical flex for a club swung at the seen speed, and that could change things by a couple degrees in addition to the 32˚ loft minus 3.4˚ AoA minus extra forward shaft lean, but what you quoted is just wrong and doesn't make sense.

Thanks. That's kind of what I thought, but I figured since that's such a highly regarded blog, it must be correct. Glad to know I'm not THAT dumb...

Originally Posted by saevel25

Spin Loft = Dynamic Loft - Angle of Attack

Dynamic Loft = Spin Loft + Angle of Attack

Spin loft is determined by the loft of the club, and the dynamics of the shaft at impact. So its really tough to measure, but even if the hands are ahead of the ball at impact, theres no way that there turning a 32 degree club into an 12 degree club on a normal shot.

Yeah, didn't seem right to me. Thanks for the info.

[iacas]

Average LAUNCH ANGLE for a 6-iron on the PGA Tour is north of 14°.

http://mytrackman.com/TrackMan.Online.DrivingRange/PGANumbers.html

[Beachcomber]

Not sure if this will help or hurt the conversation... But here is my 6i Trackman numbers from a golf clinic I attended in March.

I'm using an MP-59 6i 30-deg static loft - hitting off a lie board - outdoors on a range.

[Beachcomber]

Originally Posted by deronsizemore

That's exactly thought I thought it was calculated but reading this I'm not sure:

[quote]In the sample we are dealing with, the golfer is hitting a 6-iron which has about 32* of loft. The golfer had a -3.4* attack angle which is about the Tour average and likely had some forward shaft lean.

The result? It took that 6-iron loft and turned it into a 11.3* loft at impact.[/quote]

How do you take a 6 iron with 32* of loft with a -3.4 AOA and get a dynamic loft 11.3*? Like I wrote in my first post, they've got the bit about "adjusting for the impact of a bended shaft" but that doesn't help me figure out how they end up with 11.3* dynamic loft.

Also, your quote states 11.3* loft at impact.  That doesn't mean dynamic loft... I believe your quote is referring to Launch Angle.

Here is the calculation for Launch Angle (taken from Trackman website):

Driver.............. Launch Angle = (Dynamic Loft) + ((.85%) (Angle of Attack))

Irons............... Launch Angle = (Dynamic Loft) + ((.75%) (Angle of Attack))

So in your example, for a 6i of -3.4 AoA and 11.3* Launch Angle... The Dynamic Loft was actually.....

Dynamic Loft = (11.3) - ((.75%) (-3.4)) = 11.3 - (-2.55) = +13.85

[iacas]

Originally Posted by Beachcomber

Also, your quote states 11.3* loft at impact.  That doesn't mean dynamic loft... I believe your quote is referring to Launch Angle.

Here is the calculation for Launch Angle (taken from Trackman website):

Driver.............. Launch Angle = (Dynamic Loft) + ((.85%) (Angle of Attack))

Irons............... Launch Angle = (Dynamic Loft) + ((.75%) (Angle of Attack))

So in your example, for a 6i of -3.4 AoA and 11.3* Launch Angle... The Dynamic Loft was actually.....

Dynamic Loft = (11.3) - ((.75%) (-3.4)) = 11.3 - (-2.55) = +13.85

I get 16.2 quickly doing things, actually. 11.3 is 14.7 away from the AoA, and so the dynamic loft should be 19.6 away from the AoA, or 16.2 away from horizontal.

Plus I'm certain you didn't mean 0.75% or 0.85%.

But there's a lot more to it than that. 11.3 is still really low, though, so I don't know if we should waste time figuring out numbers that may be junk anyway.

[deronsizemore]

Originally Posted by Beachcomber

Also, your quote states 11.3* loft at impact.  That doesn't mean dynamic loft... I believe your quote is referring to Launch Angle.

Here is the calculation for Launch Angle (taken from Trackman website):

Driver.............. Launch Angle = (Dynamic Loft) + ((.85%) (Angle of Attack))

Irons............... Launch Angle = (Dynamic Loft) + ((.75%) (Angle of Attack))

So in your example, for a 6i of -3.4 AoA and 11.3* Launch Angle... The Dynamic Loft was actually.....

Dynamic Loft = (11.3) - ((.75%) (-3.4)) = 11.3 - (-2.55) = +13.85

Originally Posted by iacas

I get 16.2 quickly doing things, actually. 11.3 is 14.7 away from the AoA, and so the dynamic loft should be 19.6 away from the AoA, or 16.2 away from horizontal.

Plus I'm certain you didn't mean 0.75% or 0.85%.

But there's a lot more to it than that. 11.3 is still really low, though, so I don't know if we should waste time figuring out numbers that may be junk anyway.

Wait... maybe there is a typo (in the original article I linked too) here, but with the formula for how to calculate dynamic loft? According to Saevel25 earlier:

Spin Loft = Dynamic Loft - Angle of Attack

Dynamic Loft = Spin Loft + Angle of Attack

If you take that formula using the trackman numbers supplied at the top of the blog entry, it works out to 11.3 degrees of dynamic loft. In the article, he has "Static Loft + Attack Angle" where I think he meant "Spin Loft + Attack Angle?"

11.3 - -3.4 = 14.7 Spin Loft

14.7 + -3.4 = 11.3 Dynamic Loft

Correct?

[iacas]

Originally Posted by deronsizemore

If you take that formula using the trackman numbers supplied at the top of the blog entry, it works out to 11.3 degrees of dynamic loft. In the article, he has "Static Loft + Attack Angle" where I think he meant "Spin Loft + Attack Angle?"

Static loft is basically irrelevant in the middle of a swing, yes. :)

[deronsizemore]

Originally Posted by iacas

Static loft is basically irrelevant in the middle of a swing, yes. :)

Makes sense now.