Face To Path and Spin Axis

Good point - I see the same thing

I expected the face to path direction would be the same as the side spin direction. I'd like to understand why in some cases its not. Like the example you show above f2p right but spin axis left 

If I recall the theory (but please check) when teaching how to hit a fade is to keep your club face angle to be half the value of the club path angle and both the same direction L (left) and the side spin direction will be R. For a draw it is the opposite. Ideal spin axis is in range 3-6 deg. The spin rate is usually close to the number of the iron times 1000 eg 7 iron spin rate=7000. A club path L (left) with club face 0 deg to R(right) will start slicing. Trackman website will probably have all the theory on what to target in order to hit a certain shot

Hi Scott, what's your thoughts on the data though?  Look at the data 2 shot. The club face is almost square but the path is very much in to out (right direction)- the spin axis produced is right. I'm also getting readings like this. Data shot 1 is what I'd expect where the face to path relationship is right which make the ball spin right. 

I’m not sure how Garmin calculate the spin axis but I think it is a function of the spin loft and face to path not the club path. The 2 data shots have different attack angles so the spin loft will be different if the dynamic loft is the same so this might be why spin axis is different?

Spin loft = dynamic loft - attack angle = compression?

Spin Axis – The tilt angle relative to the horizon of the golf ball’s resulting rotational axis immediately after separation from the club face (post impact).

Copied from trackman website 

I agree that face to path is what primarily determines the spin axis which is what we are talking about here. If the face is left of the path the ball should spin left (unlike the shot 2 reading). The loft will  impact how far left, but I can't see how it would change the direction. 

The only other thing I can think of that would explain the reading is gear effect, but that's not stated as something that the r10 measures. 

On outdoors environments R10 calculates Spin Axis observing ball flight curvature, tracks firsts 50 yards of flight. Measuring position over time estimates changes in direction as spin axis, lifting and drag/deceleration estimates Spin Rate.

If you hit balls outdoors with strong lateral wind you'll see R10 reading the ball flight as you see it on the range/course even when the face to path is neutral or in the other direction.
If you hit balls into the wind you'll see a big increase in spin rate (backspin) because the wind causes the ball to rise and reduce their speed faster
The errors with long irons and woods I think is due the greater ball speed and lower spin have little effect in the firsts 50 yards of flight then any error will end on a under/over estimated reading of curvature. (I normaly see the ball curving in the last part of their flight, when the forward speed is lower is easier to see the ball curving)

I think R10 calculates Face Path from ball launch angle and clubhead path, because Spin Axis is measured/deduced only from the ball flight the results could be diferent.
With no wind, center clubface contact and neutral turf-iteration the Spin Axis must the proportional to the face to path relation and the club loft.

I had the same on an outdoor range. However,  I had a cross wind which I think may have effected the numbers.

Wind blowing right to left will push the ball left and the r10 would see that as a draw or hook even though the face was open and should be a fade.