Brian, I'm new to your forum, but definitely not new to this arguement, TGM, or online forums. I wanted to pot some things from another forum (I wrote them). I want to be VERY clear. I'm not saying you CAN'T hit down with the driver, I'm saying it's more effecient (in terms of physics) to hit up (and not up like you're trying to send the ball into the clouds, but up as in 3-4*)
QUOTED from GolfDigest's article on Hank Kuehne:
At impact with a test club, Hank's swing speed is 127 mph with a 2.8 degree upward path. His clubhead loft is 7.4 degrees at impact, because of forward shaft lean. The upshot: a launch angle of 10.4 degrees and ballspeed of 183 mph. (endquote)
The other interesting thing you see here is that forward shaft lean and a downward blow are NOT the same thing. As TMs equipment shows, he has the club leaning forward, and is hitting up.
http://redgoat.smugmug.com/gallery/84599 In that picture hank MUST be hitting up on the ball, or he's just but a 130mph skymark in it.
Jack Nicklaus says: "What you want in a driver swing is minimum backspin with maximum forward impetus."
how do we acheive minimum backspin (which WILL give you the highest forward impetus, all else equal)? Simply put, by hitting the ball as (and I hate to use this term, because it isn't exactly a word) non-obliquely as possible.
What is an oblique hit? This is how sidespin is imparted. comming from the outside, with an open face (aka bananna slice) is a classic example of an oblique hit. the club is travelling in a far different path than the clubface orientation. In terms of physics, this is NO different than swinging down with a lofted club (in one, the club is tarvelling left, with the face pointing right, the other has the club travelling down, with the face pointed up).
The way to minimize sidespin is to have the face of the club perpendicular to the path of the club. In like manner, the way to minimize backspin is to hit the ball with the path of the club as closely resempling the launch angle of the ball as possible.
why is hitting up better? is vector physics (math) really. without getting into the hard math: if you're swinging downward, that's the way the force will be directed onto the ball, so the ball would go into the ground with a 0* club. The loft of the club however creates a situation where the blow is delivered obliquely to the direction of force (a blow delivered obliquely to the line of travell is what causes ALL types of spin - even TGM says this), so what you have is the force being directed downwards, deflected obliquely, causing lift, and spin amplified.
why is this inefficient? because if you add two vectors at a right angle, the product of the two will be less than the sum of the parts, because they are added angle. Think of a stair case...12 inches in, then 12 inches up, but the vector sum of the two (or the distance from one stair to the other) is just short of 17 inches...a loss on 7 inches. I hope that makes some sense...it's tough to explain vectors without being able to draw. Now the conditions are actually worse when you hit down on the ball, because it's added at an accute (less than 90*) angle, meaning that one vector FIGHTS another...you hit down, but the lift wants it to go up. so taking the stair analogy, the distance between the two corners (or the vector sum) with a 60* angle would be 12"...a loss of 50% of the force -- this is far more extreme than what could ever happen in a driver swing, but you get the point.
Now imagine the two vectors were added at an obtuse (greater than 90*) angle. the two vectors would assist each other, until they are added at 180* (a straight line). 180* or anything close to it really isn't possible, so let's forget about that...but at 180*, the two would add to 24"...a 0% loss of power. By getting closer to that number, you will launch the ball more efficiently.
There is one thing different about golfballs though -- they are designed to create a partial vacuum and add lift with backspin...so backspin is necessary (and why you wouldn't want to have that 180* case come true), because it keeps the ball in flight longer. creating extra spin kills the ball by creating too much lift though.
I hope that clears up any confusion that's been generated about this topic.
