Friction has a big roll in spin generation particularly with irons. If there is less friction then there is less spin. This is the infamous 'flyer' that occurs with irons where the ball goes much further then expected. Also the tee shot that dips when the driver face is wet is also caused by less friction.
Grass, dirt and moisture between the ball and club face are the main culprits that lower friction and cause the flyer.
Lately I've been noticing that flyers occur mainly in short irons and that the opposite is occurring in longer irons i.e. more spin is being produced then expected from lies that cause flyers e.g. grassy or wet. This also means instead of the ball travelling further then expected, it's actually travelling less.
Recently I hit some shots from wet grassy lies to test what I've been noticing. I hit 10 shots with each iron from pitching wedge to 4 iron and recorded the results on a Trackman 111 launch monitor. It was a really nice December day around 10 degree Celsius and little wind. The Miura MB 001 was the iron used and the ball used was the Titleist Pro V1.
An example of a wet grassy lie that leads to flyers.
Below are the results from the test.
Both these golfers were hitting from slightly longer then fairway grass and we can see in the shorter irons spin rates are less then expected and in the longer irons spin rates are higher then expected.
I'm not sure at all, more investigation is needed. It also seems to happen only in irons as spin rates decrease on woods and hybrids due to decreased friction (think of the dipping tee shot due to a wet wood face). It also seems that it is around the loft of a six iron (30-32 degrees) that the change in spin rates in irons seems to happen.
In 'flyer' lies e.g. wet and grassy, long irons travel less then expected and shorter irons travel more then expected. This needs to be taken into consideration in club selection, e.g. trying to carry water with a long iron from a slightly damp semi rough lie might be a bad idea. Playing a 7 iron from 'flyer' lies might lead to much better results then long irons.
Questions and comments are appreciated.
Grass, dirt and moisture between the ball and club face are the main culprits that lower friction and cause the flyer.
Lately I've been noticing that flyers occur mainly in short irons and that the opposite is occurring in longer irons i.e. more spin is being produced then expected from lies that cause flyers e.g. grassy or wet. This also means instead of the ball travelling further then expected, it's actually travelling less.
Recently I hit some shots from wet grassy lies to test what I've been noticing. I hit 10 shots with each iron from pitching wedge to 4 iron and recorded the results on a Trackman 111 launch monitor. It was a really nice December day around 10 degree Celsius and little wind. The Miura MB 001 was the iron used and the ball used was the Titleist Pro V1.
An example of a wet grassy lie that leads to flyers.
Data
Below are the results from the test.
|
Club
|
Club Speed (mph)
|
Ball Speed
|
Launch Angle
|
Spin Rate
|
Carry (yards)
|
Total
|
|
PW
|
80.1
|
93.4
|
28.6
|
5218
|
118.8
|
125.1
|
|
9i
|
81.5
|
100.4
|
26.0
|
4633
|
135.3
|
143.7
|
|
8i
|
84.7
|
107.5
|
19.6
|
6736
|
139.1
|
144.8
|
|
7i
|
87.3
|
114.1
|
17.7
|
5686
|
150.5
|
158.3
|
|
6i
|
89.6
|
119.6
|
13.8
|
6402
|
158.4
|
166.1
|
|
5i
|
90.4
|
123.1
|
13.1
|
6332
|
164.4
|
172.4
|
|
4i
|
92.6
|
126.4
|
11.3
|
5207
|
172.9
|
184.1
|
What spin rate would we expect from each club? Spin is calculated by club speed x spin loft x 2.6 for irons. For the 9 iron above we would expect 81.5 x 34.6 x 2.6 = 7,332 and the 4 iron would be 92.6 x 17.3 x 2.6 = 4,165. A reasonable rule of thumb to calculate spin for an iron is to multiply the iron number by 1,000 e.g. 4 iron 4,000, 5 iron 5,000 etc.
Looking at the data, the spin for the 9 iron was 4633 on average, much lower then expected, this is what a flyer would be, ball travelling further through the air and running more on landing. The spin for the 4 iron was 5207, higher then expected which means ball doesn't fly as far and runs less on landing.
The 7, 8, 9 and PW have spins less then expected. The spin for the 6 iron is slightly higher then expected and much higher then expected for the 4 and 5 irons.
Below is data taken from shots taken by two more golfers during the Summer.
|
Club
|
Club Speed (mph)
|
Ball Speed
|
Launch Angle
|
Spin Rate
|
Carry (yards)
|
Total
|
|
8i
|
87.8
|
111.5
|
28.3
|
4080
|
160.6
|
169.7
|
|
4i
|
96.3
|
123.4
|
15.7
|
5633
|
175.3
|
187.3
|
|
Club
|
Club Speed (mph)
|
Ball Speed
|
Launch Angle
|
Spin Rate
|
Carry (yards)
|
Total
|
|
9i
|
89.6
|
114.6
|
23.1
|
5694
|
159.9
|
167.7
|
|
5i
|
101.5
|
136.9
|
10.7
|
6490
|
190.5
|
199.3
|
Both these golfers were hitting from slightly longer then fairway grass and we can see in the shorter irons spin rates are less then expected and in the longer irons spin rates are higher then expected.
Why does this happen?
I'm not sure at all, more investigation is needed. It also seems to happen only in irons as spin rates decrease on woods and hybrids due to decreased friction (think of the dipping tee shot due to a wet wood face). It also seems that it is around the loft of a six iron (30-32 degrees) that the change in spin rates in irons seems to happen.
What this means for your golf?
In 'flyer' lies e.g. wet and grassy, long irons travel less then expected and shorter irons travel more then expected. This needs to be taken into consideration in club selection, e.g. trying to carry water with a long iron from a slightly damp semi rough lie might be a bad idea. Playing a 7 iron from 'flyer' lies might lead to much better results then long irons.
Questions and comments are appreciated.
