Posts Tagged ‘height’
I recently stumbled onto an interesting tidbit whilst working with a young professional on his wedge game. It was early in the morning and we had been hitting beautiful 50 yard pitches the afternoon before and suddenly he could not get the ball to launch low enough with the spin rate he had been generating the day before. Now as you may know I’ve tested almost all there is to test in regards to a 50 yard wedge shot and of course I had looked into the effect of water interfering with the friction between the face and the ball. One problem – I had tested a wet club striking a dry ball. My results from the earlier test showed very little difference in launch and spin when there was water involved and I had since adopted that belief.
As I watched the young pro struggle to lower his launch in the morning dew it came to me – there was a difference between a wet club striking a dry ball and a dry club striking a wet ball! I had to run the test again.
I had to be very careful with the test in that I needed to use the same club, my 54 degree sand wedge, in very controlled conditions, with golf balls that were consistent. I used brand new Titleist NXT Tour golf balls and made sure that I cleaned the grooves and clubface off between each shot. I attempted to hit each shot to carry 50 yards flat and hit eight shots for each portion of the test. I removed the two shots that had the lowest spin from each portion. With the help of my TrackMan here are the results:
Wet club and dry ball:
- Launch angle was 27.8 degrees
- Spin rate was 5463 rpm
- Height was 26.5 feet
Dry club and wet ball:
- Launch angle was 30.1 degrees
- Spin rate was 5291 rpm
- Height was 28.4 feet
Dry club and dry ball:
- Launch angle was 25.4 degrees
- Spin rate was 6603 rpm
- Height was 21.2 feet
The interesting thing in looking at the trajectory chart is how much lower the dry club and dry ball (purple) shots flew. Clearly there was more friction between the face and ball which led to a lower launch with substantially more spin. The dry club and wet ball (yellow) sample flew the highest as the water on the ball greatly decreased friction which led to higher launch, due to slippage and thus decreased spin – certainly not the optimal shot.
The interesting thing when comparing the wet club/dry ball versus the dry club/wet ball results was that the spin and launch were better when the BALL was dry. This was due to the water being forced off the clubhead and into the groove channels during the motion of the swing. Not to mention that the air dried the face during the swing too.
Moral of the story – always clean the clubface (unless it has sand on it) and dry the club and ball when possible. If you happen to have an early morning tee time and you’re a dew sweeper, don’t plan on hitting any low spinners! The drier the ball and club, the better the friction and the better the quality of shots you will hit.
Please read my first two articles on wedges and pitching:
My wife encouraged me to clean out the garage the other day and I happened upon an old driver I used in college. I still remember how cool this driver was – it was the latest and greatest and even had a titanium shaft! When was the last time you saw one of those? Just for kicks I placed it up alongside my current Titleist driver and was shocked at the massive difference between the two – the older club looked smaller than my current three wood! How could I have possibly played well with this mini club? This got me thinking about a TrackMan test.
For the record the smaller club was a TaylorMade Burner Plus 9.5 degree with a titanium X flex shaft and my current club is a Titleist D3 8.5 with a Motore F3 70 gram graphite S flex shaft. There is a fairly substantial 1.5 inch difference even though both clubs were standard length in their day. I am not sure about the weight or the true frequency/flex of each club as I did not have the appropriate equipment to check those measurements.
For the TrackMan test I hit 12 shots with each club and deleted the data for the two worst shots. I noted that the attack angle, club path, swing direction and plane were very similar from club to club.
The primary differences seemed to be:
- Club speed 99.7mph vs 101.8mph – I believed that this difference would be greater due to the large difference in length of shafts.
- Ball Speed 145.7mph vs 152.4mph – I put this down to the fact that the smaller head led to more off-center hits and thus a decreased average ball speed and smash factor.
- Point of contact – there was a noticeable tendency for me to strike the bigger club in the heel. This led to more shots missed to the right due to gear effect and an increase in the spin rate 2455rpm vs 2895rpm.
- Height – even though the smaller club launched the ball slightly higher the apex height was lower due to less spin and ball speed.
- Carry and total distance – the smaller club carried the ball almost 17yards shorter, but with less spin and a flatter land angle rolled further to only finish just over 10 yards short of the bigger club.
- Dispersion – the smaller club had more shots finish further from the center line due to a much smaller clubface and substantially lower MOI.
Here are the TrackMan generated dispersion charts (yellow is the smaller club) and averages:
(click to enlarge)
I was amazed at how small the difference between the two drivers, total distance wise, there was. Going in to the test I would have thought that there would be a 15 yard difference at least. I expected the smaller club to spin the ball less and lower the apex which it did, but I was truly amazed at how little distance I lost with it. I did notice a much greater tendency to hit the ball outside the sweet spot with the smaller club and that led to some fairly aggressive gear effect draws and fades.
Driving is not my strong suit and I am always looking to keep the ball in play off the tee. Armed with this new knowledge I am going to try a shorter shaft in my current driver head and see what that does for my fairways hit statistic. I also plan on practicing with the older club – I think it is vital in improving ball striking to practice with smaller headed clubs.
I also think this test might also illustrate that the majority of the distance gains we see on the PGATour today are not equipment based, but primarily due to the ball…..your thoughts?
In my quest to better understand pitching, chipping, and more specifically the low spinning wedge shot I needed to watch different professional players hit a variety of shots and be able to track the data from each shot. My objective was to understand how friction or grip between the face and the ball influenced the launch angle, height and spin rate. I have named the measurement of this grip and it’s influence on the golf ball – friction launch.
I need to explain some fairly detailed physics as to how I measure friction launch, so bear with me. The golf ball always launches somewhere between where the face is angled and where the clubhead is travelling – on both a vertical and horizontal plane. The ball also always launches closer to where the face is angled than where the clubhead is travelling. Where the ball launches between the face angle and the clubpath is primarily determined by club speed and friction between the face and ball. I needed to measure this friction in order to see how it effected the trajectory and spin on wedge shots.
With the help of Mark Reilly and Edoardo Molinari, we came up with the following formula to determine friction launch:
(Dynamic Loft – Launch Angle) x 100/Spin Loft = Friction Launch
This formula informs us where the ball launches between the face and path. The percentage indicates how far below the face angle the ball launched. A friction launch of 0% indicates that there was absolutely no grip at impact and the ball launched in the direction the face was angled at impact. A friction launch of 50% would indicate that the ball launched directly between the face angle and the clubpath and the grip was exceedingly high. By the way – neither of these are possible under normal conditions. The smaller the percentage, the higher the launch and lower the spin and vice versa.
With all the various situations I tested I needed to keep certain factors constant in order to be able to detect why the trajectory and spin rate of each shot was altered. My constants were TrackMan – to record the data; the golf club – a Titleist Vokey SM4 54 degree wedge; and the distance of each shot studied – 50 yards. If any ball landed short of 40 yards or longer than 60 yards it’s data was thrown out. The factors I controlled were the quality of the lie and playing surface, the grass and dirt in the grooves and on the face and the type of golf ball.
Here are the average results attained from three professional golfers hitting 10 shots each in 7 different situations:
1. Clubface packed with dirt and grass/ProV1/off lie board (to eliminate additional matter)
- Friction Launch 17.9 degrees/Spin Rate 4408/Launch Angle 34.9 degrees/Height 31.9ft/Carry 51.6yds
2. Clean clubface/ProV1/off lie board (to eliminate additional matter)
- Friction Launch 28.1 degrees/Spin Rate 6501/Launch Angle 28.4 degrees/Height 25.1ft/Carry 50.3yds
3. Wet clubface/ProV1/off lie board (to eliminate additional matter)
- Friction Launch 28.1 degrees/Spin Rate 6564/Launch Angle 28.7 degrees/Height 25.7ft/Carry 50.4yds
4. Clean clubface/ProV1/off turf/preferred lie
- Friction Launch 31.9 degrees/Spin Rate 7178/Launch Angle 26.1 degrees/Height 22.3ft/Carry 48.9yds
5. Clean clubface/hard range ball/off turf/preferred lie
- Friction Launch 28.8 degrees/Spin Rate 6625/Launch Angle 27.6 degrees/Height 25.1ft/Carry 50.8yds
6. Clean clubface/ProV1/off a new mat
- Friction Launch 30.4 degrees/Spin Rate 6859/Launch Angle 26.8 degrees/Height 23.3ft/Carry 49.2yds
7. Clean clubface/ProV1/Off a tee
- Friction Launch 30.6 degrees/Spin Rate 7259/Launch Angle 27.6 degrees/Height 24.8ft/Carry 51.2yds
Edoardo Molinari was also kind enough to submit his TrackMan data to me from the 10 shots he hit with his 60 degree wedge and 10 more with his 56 degree wedge: (the following shots were hit with premium golfballs, off preferred lies and cleaning the clubface between each shot)
60 Degree Wedge
- Friction Launch 22.9 degrees/Spin Rate 6048/Launch Angle 36.2 degrees/Height 34.8ft/Carry 51.0yds
56 Degree Wedge
- Friction Launch 24.4 degrees/Spin Rate 6046/Launch Angle 34.2 degrees/Height 31.5ft/Carry 50.5yds
NOTE: After a few weeks of practice Edoardo has improved his 10 shot average with his 60 degree to a spin rate of 8700rpm and a Launch angle of 26.1 degrees! There is something to this…
The deductions I took from the above tests are as follows:
- Shots out of the rough, first cut or even into the grain lies are always going to launch higher, spin less and as a result fall out the sky faster and roll more after landing – no matter how good you or your wedge is. There simply is too much ‘matter’ involved between face and ball to create optimal friction.
- A wet clubface actually makes very little difference in determining how much friction, and thus spin, is imparted on the ball.
- A premium golfball makes a noticeable difference with the wedges. Not only will it add distance off the tee, but it will also allow you to hit better and more predictable short shots.
- If the rules allow you to tee the ball up – go ahead and do so. You increase your ability to place the clubface cleanly on the back of the golf ball.
- Hitting pitch shots off mats is a fantasy world and can only increase the ‘illusion of competence’. No bad lies, nothing between the face and the ball, minimal consequence to heavy shots...
- For pitch shots, higher lofted clubs do not spin the ball significantly more than the next wedge down (60*vs56*). They do, however, get the ball to stop slightly faster due to a steeper landing angle.
- Average friction launch for a 50 yard shot is around 25%. The lowest friction launch was out of the poorest lie (18%) and the best results came from an ideal fairway lie, a new and clean wedge along with a premium golfball (32%).
- The quality of the lie is the most important factor in allowing a golfer to control the trajectory and spin of the wedge shot they are about to play.
Let’s take a look at the factors that influence friction launch:
The Golf Club
- The sharpness of the top edge of the groove will effect spin, yet most of the spin on a shot comes from the roughness of the area between the grooves.
- In my opinion the wedges that provide the highest amount of spin are the models that have the roughest surface between the grooves – the new TaylorMade ATV and the Nike Vr Pro wedges seem to do an excellent job with ‘between groove’ treatment.
- An excellent way to improve spin with your current wedges is to have the face sandblasted with normal aluminum oxide sand. This will provide a rougher, more ‘grippy’ texture to the face.
- The number of groove edges that come into contact with the ball also effects backspin. In pushing the limit of the groove rules manufacturers can now put five grooves on the surface of the ball at impact versus the traditional three.
- Grooves channel away some of the moisture and matter from rough that gets between the ball and face – but seldom all of it.
- The grooves and face of your wedges should always be very clean – even when you’re practicing. Keep a towel or brush handy to clean the club after every few shots.
- If you are serious about competitive golf I would recommend having a tournament set of wedges and a set you use in practice. Every shot you hit wears down the face which reduces friction at impact.
- In fact Gary Player would ensure that his caddie never cleaned his wedge after hitting a sand shot – the sand particles on the face helped to create more friction between the face and ball for his next shot.
Turf Type and the Quality of the Lie:
- When you are into the grain you will often get grass caught between the ball and the face, thus reducing grip. A down grain shot will ‘cut’ very little grass and thus allow for clean contact and increased grip.
- Different turf types are thicker and stronger and thus, even at fairway height, support the ball enough to keep it up and away from the grass. This makes it easier to have a higher friction launch factor. If you’ve ever played off kikuyu grass you’ll know what I mean.
- When laying up on a par five understand the value of high friction launch – lay up in the fairway and don’t be greedy.
- This is where I am now focusing my efforts. There does seem to be a method that DOES NOT involve a more open face, increased speed, higher launch or a cutting action that seems to produce a lower trajectory with a much higher spin rate. Stay tuned…..
Read part one of this article HERE
With so many questions after my two most recent posts I thought it would be enlightening to show you what we see when using TrackMan. This particular driver was hit by Rick Hartmann – my boss and the Head Professional at Atlantic Golf Club. Rick played on the European Tour for ten years and is a fantastic driver of the ball. This is a good drive, but not anything unusual for Rick (it was into a very slight headwind). These particular numbers are very close to optimal and should be something we should all be working towards regardless of what our club speed might be. Of course that is if you happen to like high, long draws…
If you want to be efficient with your driver here is an explanation of what I look for:
- The Attack Angle (0.9 degrees up) is positive – a good sign for maximum efficiency as an upward hit is better than a downward hit (if you want to hit it as far as possible).
- Notice how (because the Swing Plane is very close to 45 degrees) that the Attack Angle + Club Path = Swing Direction. Not unusual really, this is a helpful indicator in understanding what factors effect the club path.
- The Spin Loft is close to 11 degrees – a solid number that seems to work for most golfers. Spin Loft = Dynamic Loft - Attack Angle. Think of spin loft as a measure of ‘ball compression‘.
- In order to hit good draws the face must be open relative to the target at impact and here you see how the Face Angle is open (2.7 degrees) with the Club Path being further to the right (3.5 degrees). Couple that with a centered hit and you’ve got lovely push draws.
- A centered hit is vital and that’s why I like to keep Face to Path alongside Spin Axis. If the hit is in the heel the face angle would be closed ( a negative number) and the spin axis would be tilted to the right (positive) and vice versa for a toe hit. Here you see how with the face slightly closed to the path, you should get a baby draw, and that’s exactly what we got – all from a centered hit.
- Club Speed and Ball Speed are fairly self explanatory, but if you divide the club speed into the ball speed you will get 1.48 which equals the Smash Factor. Smash factor is merely a measure of how efficiently you translated club speed into ball speed and is not purely a measure of how well you struck the ball. The maximum smash factor for a driver 1.53. (I have seen 1.54 twice!)
- The Height of the shot, which is measured from flat and not necessarily the ground, is right where I’d like to see it for this particular club speed. PGATour average swing speed is 112mph and they hit all their clubs 90 feet in the air. At around 108mph I think 88 feet high works very nicely.
- Launch Angle and Launch Direction are largely influenced by the club face and I like both here. I look for draws to launch to the right of the target (positive) and the launch angle to be somewhere between 10 and 16 degrees depending on the players club speed.
- The Spin Rate for this shot is a touch high, but I would attribute that to a shaft that is softer than what the golfer should be using. I’d like to see the spin rate at this club speed be somewhere between 2000 and 2200.
- Side Total indicates that this ball is straight down the center and finished less than 4 feet right of the intended target line – just another ho-hum 280 yard drive down the pipe.
Somewhat advanced I know, but after the response to my last few posts I know there are thousands of golfers out there who are looking for a better understanding of what really happens at impact and what they should be working towards for maximum efficiency. If you can duplicate these numbers you won’t need me for much…at least not for the driver.