Spinloft according to TM

[wulsy]

Trackman states that spin loft generates spin and that spin loft remains largely unchanged when AoA is changed.

So why did Kyle Stanley's ball spin back off the green when he hit it in so low and others who hit it in higher did not suffer a similar fate? And why generally are low flying shots more likely to "spin back" than higher shots?

 

[ZAP]

I'll take a blind guess and say friction.

 

[mgranato]

I didn't see his shot. Was it a partial wedge?

 

[wulsy]

From about 75yds (from memory).

 

[ZAP]

I used to spin the crap out of my wedges before learning some of the stuff here. A back pin was out of the question for me pretty much unless the greens were concrete. And even sometimes then.

 

[Brian Manzella]

Funny you should ask:

Big Play: Kyle Stanley's spinning wedge shot into pond on final hole at Torrey Pines | GOLF.com

This is an article I did for Golf Magazine today.

It's been edited a bunch for length, but here is the general idea.


(pure-d guesses, I will try to get real numbers tomorrow)

SPIN LOFT for LOW SPINNY WEDGE: downward AoA 10° + dynamic loft 30° = 40° of spin loft, launch angle 18°
SPIN LOFT for LESS skinny WEDGE: downward AoA 4° + dynamic loft 32° = 36° of spin loft, launch angle 22°

 

[mjstrong]

I'd say that, because the low shot is in the air for a shorter period, it RETAINS more of its initial spin than a shot traveling through more air with more hang time would.

 

[mjstrong]

Brian, what are some of your keys to hit down by 6 more degrees while only reducing dynamic loft by 2?

Less shaft lean? Ball position back? Less axis tilt at impact?

 

[SteveT]

Angle of descent at impact with the green?

 

[wulsy]

But on the other hand, mj, it has much more forward momentum thus requiring more spin to stop it. And they always seem to bite in on the 2nd or 3rd bounce, after the ground has negated some of the spin. So it's still a bit of a mystery to me how these shots always seem to be the ones which spin back off the green.

In your example Brian, do you have any numbers for the actual spin rate produced?

 

[mjstrong]

But on the other hand, mj, it has much more forward momentum thus requiring more spin to stop it.

True, but in this case, like SteveT mentioned, pitching into the angled green probably helped start it backwards sooner.

 

[mgranato]

What about speed?