Face angle vs. lie and loft

[joostin]

Sharing some numbers that some might like for reference. There's been plenty said of lie angles being too upright or flat causing the face angles to be left or right of the target, and that effect is amplified the higher the loft. We know that's why it's so important especially on wedges to have your lie angles corrected. My google search came up empty to see what kind of face angle numbers those are. So I modeled it up in CAD to figure them out because that's what I like to do. For example a 60* wedge at 3* toe up for a righty (3* toe down for a lefty) will have a face angle (horizontal like the Trackman reading) of 5.19* pointing left of the target line. A 30* 6 iron at 2* up or down will be 1.16* offline:

I just did numbers for 10* increments and 1* to 5* lies because it gets tedious, and you can kind of extrapolate from there even though it not linear. The same numbers apply for "flat" or "upright", or negative lie #s if that makes sense. This is all assuming that the leading edge is perpendicular to the target line. If anyone wants to see specific lofts/lies let me know. Hmm just thought, maybe I'll try something like a 56* wedge opened 30* to target like a bunker shot... effective loft changes too. This can get interesting.

[Howard_Jones]

Nice, but the reason you did not find it, is most likely because FACE ANGLE does not change

A lie angle thats upright or flat at impact TILT the LOFT PLANE like your illustration show, face angle remains unchanged.

The offline numbers you get would be right if the ball did not spin, so those numbers represent how far off the Loft plane points vs target line.

[Stuart_G]

If you enjoy doing that kind of thing, that's great.

But just in case you weren't aware, it has been done before.https://www.tutelman.com/golf/design/lie1.php

[joostin]

Seriously?! That's exactly what I couldn't find and pretty much the same table same, lol! Thanks Stuart, should've known to check his site. Though I trust my numbers off the CAD more than Tutelman's - they're a little different and I don't see where he got his numbers from. Oh well.. got a little CAD model to play with now.I think we're talking about the same thing, just the name "face angle" I took as Trackman's definition: https://blog.trackmangolf.com/face-angle/

Basically my blue dotted line "Axis1" from a top view pointing left or right of the target line, purely from a geometric perspective regardless of spin. Effective loft, if that's the name, should change too, but I'll check.. looking perpendicular to the target line with Axis1 vs the ground. Looking down along the the leading edge the loft remains the same, but along the ground line should change. Will be interesting to see what "opening up" a sand wedge does to all the angles.

 

[Howard_Jones]

Ohhh ...... you are reading that definition wrong, the way Trackman explains this is with a neutral lie angle or loft plane, so its NOT face angle that changes here.

Think of face angle as something we can adjust by rotating the shaft, while lie angle is NOT rotation, but "in and out" with the grip from ourselves, so when we adjust lie angles, its to make it fit with our hand position at impact where "high hands" = upright, and "low hands" = flat

Here is 3 examples of face angles, thats what we talk about when that term is used. (just overlook the rest of the illustration, its got nothing to do with this)

Your own illustration of the tilted loft plane is correct, and thats what happens when lie angle is off at impact, but we dont use the term face angle, it remains the same.

The tilted loft plane dont change dynamic loft, (or back spin) but it makes a tilt on the spin axis on the ball vs the horizontal line since the balls Spin axis is 90* vs loft plane.

Since you already has that model up and running, run some numbers for LIE ANGLE on PUTTERS with a lie that 1-3* off and 5 -10 and 20 yards distance to see how much outside of the cup the face actually points.

[Howard_Jones]

This Trackman explanation of face angle is "better", but it should be common knowledge - choose face angle when you get therehttps://trackmangolf.com/what-we-track

[Stuart_G]

@joostin said Though I trust my numbers off the CAD more than Tutelman's - they're a little different and I don't see where he got his numbers from
Most likely he used a calculator and the equation he showed on his page.

[Adam C]

Another thing to mention that hasn't been is that drivers and fairways have bulge and roll. I have looked at the Tutelman numbers and compared them to my personal measurements (not equations, just putting clubs into my loft gauge and then start cranking the lie angle around). Everything is spot on until you get to the driver where I end up getting smaller differences, say .25 off at 4 degrees lie change. I know this is caused by the face curve and realize that the measuring point must be fractionally off but it makes me question how important it really is when it is both very small, and can be changed a large amount relative to these measurements on the driver by a small change in face contact.

[Howard_Jones]

The answer to that should be obvious...MAYBE iron Byron would see a SMALL difference, the rest of us...no way, we vary on impact position way more than your measure point moved, and we cant even deliver the club head with the same path and face angle twice on a row, not even the best players can. A 10 year old Trackman report of Rory that i have stolen from the net say that back then he had a Face angle that was plus minus 1.7*, so your number of 0.25* compared to plus minus 1.7*or 2.4* from min to max....thats really 10:1 compared to on one of the best players we know about.

 

 

[joostin]

Ahh I see what you're saying... and I'll work up the putter scenarios you mentioned. So face angle only applies when lie is perfectly horizontal with the ground? "Face direction" may be the better term for this post if that's the case to indicate the tilted loft plane. Question: In my first picture, in order to get the face pointing down the target line at 3* toe up (for a righty), we'd have to rotate the club open - leading edge no longer perpendicular to target line. Does this indicate a positive "face angle" even though the face is actually pointing down the target line (Axis1 is perpendicular to the face and will point down target line)? Just the leading edge will be open. Trackman's Doppler radar I assumed would get data off the ball to back calculate face angle where the face was pointing regardless of leading edge (?).

[joostin]

You're right, thought he was calculating distance error based on angle at first glance.

[joostin]

@Howard_Jones Here are the putt numbers you asked for and some pictures. This is assuming a putter loft of 3* at impact, leading edge square to the target line, at lies up/down from neutral by 1* to 3*. My quick search showed a 3* putter loft is pretty common these days - Ping, Odyssey, Taylormade Spider. On the last picture I included a 3.5* loft, which looks like Scotty Cameron's current lineup.
[img]https://s3.amazonaws.com/golfwrxforums/uploads/462/M1XBM1CAKPAI.png[/img]Angles off target at 3* loft are:
[img]https://s3.amazonaws.com/golfwrxforums/uploads/034/5KXTKAAN25KX.png[/img]Pics at 60 ft putt, perfectly flat green:
[img]https://s3.amazonaws.com/golfwrxforums/uploads/908/XSXMWGT5N35E.png[/img]
[img]https://s3.amazonaws.com/golfwrxforums/uploads/157/VFAMS9GSQ7HH.png[/img]
[img]https://s3.amazonaws.com/golfwrxforums/uploads/533/6D79NDE4RC7R.png[/img]Even at 60 ft, with a 3* lofted putter, toe up by 3*, you still make the putt if the ball is dying by the hole. 3.5* lofted Scotty users, sorry, you missed the 60 footer!
Edit: standard 4.25" Dia. hole, 1.68" Dia. ball shown

[Stuart_G]

@joostin 3* is fairly common for static putter loft but 1* is considered more ideal for the dynamic loft at impact.

[joostin]

At 1* dynamic loft at impact, 3* toe up or down, we will be outside the cup at 203 ft away, even farther at 1* to 2* toe up or down, so no worries!

[Howard_Jones]

Thanks, thats very nice, now its visible where the face is pointing, but we cant use this for anything else than to show where its pointing, the ball would NOT go there

Here is the issue...the tilted roll axis, (just like a tilted spin axis for balls thats up in the air) so the ball is curving away from the hole, so the illustration you made tells where the face is pointing only.

For other clubs in the bag we see from this charts that more loft = more offline on the same lie angle like 1* off, but since distance with lower lofts is so much longer than it is with high lofted clubs, the average "off target factor" is about the same for all irons, so a #3 iron or a PW with a lie thats 1* off is about the same in distance to the side from the flag. We count it as 3 yards off target for each 1* off on lie, while actual is 2.6 to 3.4 yards if i recall right (rusty memory on those details)

[joostin]

Absolutely correct. The visuals only represent face direction - no roll, spin, fiction, pressure, etc. like many a physics textbook problem. Ball just slid to the hole. Tutelman has numbers very much like what you say, roughly 3 yards error including curvature for each 1* lie error for each club.