# QA Backspin on Drivers

Editor's Note: This is the latest in a weekly Q&A feature from GOLF CHANNEL's Chief Technical Advisor Frank Thomas. To submit a question for possible use in this column, email letsbefrank@franklygolf.com

QUESTION OF THE WEEK: Every week we will select the best question and Frank will send one lucky golfer a personally signed copy of 'Just Hit It'. Last week's lucky winner was Dave, with his question regarding talented junior golfers and the best way to help them and their parents.

Backspin on Drivers

Frank,

I'm confused about some contradictory statements I've read concerning the desirability of backspin (or lack of it) when one hits a driver off the tee. The February 2008 issue of Golf Digest states, ' . . . you want to hit the ball just above the true middle of the face to launch it high without too much backspin' (p. 123). On the other hand, a book entitled Newton on the Tee: A Good Walk Through the Science of Golf states, 'The force of the air on a dimpled golf ball with backspin provides lift . . .' (p. 81). The author elaborates that the rotating ball creates a downward force on the air, and 'according to Newton's Third Law, the air must, in turn, create an upward lifting force on the ball' (P. 83). This lifting force, he concludes, alters the ball's trajectory in an upward direction.

The implication of both of these contradictory points of view is that a golfer will get more distance from his drives.

What is your view on the backspin issue?

--Tom

Tom,
Believe it or not these statements are not contradictory. A ball without back spin will fly about 140 yards compared 260 yards with backspin. This assumes all other launch conditions ' speed, launch angle etc ' are the same.

The dimples on a golf ball actually reduce the drag force through the air at speeds the ball normally experiences in flight. But it is very important to have the right amount of backspin to get the maximum distance. It is only recently -- in the last twenty years -- that we have really understood the total effect of spin in combination with launch angle and ball speed to get maximum distance. Because of the equipment these launch conditions were not achievable to the likes of Jack Nicklaus and golfers of his era.

When the ball spins ' backspin is on every shot irrespective of what some TV announcers suggest -- the air flow over the ball is such that it creates a differential in air pressure above and below the ball ' high pressure below and low pressure above. This allows the ball to experience a lift force creating a gliding trajectory through the air rather than take on the trajectory of a stone or bullet.

The problem about backspin is, that too much actually creates more drag forces giving the ball a lift force sending it into a ballooning trajectory and reduces the distance. So backspin is important, but the right amount is needed in combination with ball speed and launch angle to get maximum distance.

The reason why it has been suggested one hits the ball high on the club face is to take advantage of the vertical gear effect which will help reduce the spin getting it closer to the optimum, e.g. about 2,500 rpm for a 13 degree launch angle and a head speed of about 90 mph. In the past we have found it difficult to get this low spin rate with a 13 degree launch angle because as the launch angle increases so does the spin rate. Today drivers in combination with the multi-layered balls allow us to get close to optimum launch conditions.

Hope this helps clear up the confusion.

Frank

To Change or Not to Change Shakespeare irons?

Frank,

I enjoy your insights very much on the game we all play. I am 52 and using Shakespeare Irons with aluminum shafts. They are about 35 years old. I am about a 10 handicap player and usually play about 1 to 2 times a week. I am concerned about the difference in the action of the shafts, these do not seem to twist as much when I miss hit a shot keeping my shots more on line although the distance suffers. What type of shafts on todays clubs would be the closest to what I am using now?

Thanks Again.

--Brian

Brian,
This is an especially interesting question, because the irons you are using are probably those I designed when I was the chief design engineer for Shakespeare Sporting Goods in 1968-71 just before I introduced the graphite shaft to the world of golf. However, if these have aluminum shafts then they may have been the model year before my first head design. If this is the case then the clubs are about 40 years old and I do think that it is a good time to consider a change.

In my book Just Hit It, which was released on February 15th and is now available by Clicking Here, I caution golfers not to jump on the latest equipment immediately it is introduced each year -- sometimes three times a year ' simply because it is new. New does not necessarily mean that it will affect your performance measurably from last years model, or in fact the year before that.

Sometimes it takes a year to get your clubs and your swing in sync, broken in so-to-speak and frequent changes will disrupt this process. It is like pulling up a newly planted tree every month to see if the roots have grown. Certainly, the technology in irons cannot change rapidly enough to warrant an annual change. This is now the case with drivers as well.

However, forty years is on the edge of being too long to hold on to your clubs especially if you play twice a week. These Shakespeare clubs were not cavity backs and not very forgiving clubs. Karsten was just about to come out with his classic clubs Eye-2 irons, which turned the world of iron design on its head. These Eye-2s are still good clubs and hard to beat for forgiveness.

With regard to the shafts -- in your new set of clubs --I would recommend that you get a set of R-flex good steel shafts which will perform better than the aluminum versions you presently have.

A little bit of fun information; during impact the shaft plays no part in the way the ball flies. The head rotates about its own center of gravity (c.g.) on mishits, not the shaft. The shaft may just as well be severed from the head immediately when impact starts. The only purpose of the shaft during and after impact is to stop the club from flying down the fairway.

By the time impact is felt by your hands the ball is about 18 inches off the face and by the time you can do anything about it the ball is close to 20 yards on its way to wherever it is headed ' on the fairway we hope. You are better off talking to your ball than trying to control it during impact or getting a shaft that will affect the ball flight during this very short period of time.

Brian as much as you may like your Shakespeare clubs it is time to clean them up before they take a place on your mantel shelf. Then relax and read my book to get some interesting information about equipment and how we should try to speed up play to help make our game more enjoyable.

Frank

Frank Thomas, inventor of the graphite shaft, is founder of Frankly Golf, a company dedicated to Helping Golfers. Frank is Chief Technical Advisor to The Golf Channel and Golf Digest. He served as Technical Director of the USGA for 26 years and directed the development of the GHIN System and introduced the Stimpmeter to the world of golf. To email a question for possible use in an upcoming Let's Be Frank column, please email letsbefrank@franklygolf.com