Some Numbers

I'm sure that I will return to the long game at some point.  Golly, nothing in golf seems to last more than round and half, so I'll be back.

But I was thinking about the levers and radii in golf and thought I'd provide some actual numbers.

I'm making some assumptions here.  I could look all this up and I may, but let me jot down some actual numbers and calculations and then I'll expound about the whole thing.

My numbers:  Middle neck to shoulder joint: 9 inches,  Shoulder to start of fingers: 26 and length of a normal driver from middle of hand position to center of the club face: 42 inches.

The diameters can be calculated if we could spin these items into a fill circle.  But since about 90 degrees is all I want to for my shoulders let's start there.

A 90 degree arc for my shoulder is about 14 inches.

The arms are going to have a longer arc since they are getting somewhere over the right shoulder and then extending down to the ball.  I'll be generous and say that it's 170 degrees or 170/360 * the diameter.  That number is about 77 inches.

The final number is that of the club.  For the driver we have 3/4 of a diameter as we will get the club close to parallel above the shoulders.  That number is about 198 inches.

Let's look at ratios of these numbers.  The idea that I move shoulders back and coil the arms and club around the body and then we will spin back and unwind everything.  If the time is the same, i.e., the shoulders are finished rotating at the same time the arms and shoulders are, we can calculate the speed attained by the club head as a multiplicand of the shoulders.  We can talk about how valid this all is in a moment.

The distance the club head moves is about 14 times the shoulder movement.  Note that the swing centroid is at the left shoulder.

If we can move the shoulders at 8 miles an hour we should get about 110 at the club head.  Raise your hand if you'd like to have a club head swing of 110 MPH?  I'd love to see 100...

Caveats and there are always caveats.  1) It might be hard to move the shoulders at 8 MPH, not sure.  It seems certain people can.  2) If the "swing" times are not the same then the end speeds will not be correct.   But if the energy is the same and we get some whip at the end, it may be that parts are slower initially and then faster later.

I'm inclined to think that this might be fairly accurate at least as a model for the swing.  I believe that since at impact the hands and club are pretty much in line with the left shoulder.  So the end positions and times are pretty much the same.

The shoulders have to start it all.  But the arms stay against the chest for a time and don't have the full diameter on the downswing.  Now this is probably a good thing in re building club head speed.  The arms unfold after the shoulders have moved a bit.  Then the club swings out in the same manner.

The natural release method tells us to let the angular acceleration do this for us.  We don't want to "help" the arms or club come out and swing around.  See Tutelman.com and his swing section for more information.

I've managed to play with this a couple of rounds.  The swing has simplified to a small shoulder movement back and down and then forward.   Everything else is on its own.  I'm really happy with contact and direction. 

I had another nice range session today and I'm still a happy camper.  Big test will be Tuesday at the long course.  I play tomorrow too, Monday.

Sorry for the disjointed post here, but I wanted to get something out.