Lets start this over - pre-stress

[Ringer]

Please no hassling me, I'm not trying to prove that I'm right because I honestly don't know and want to understand. Don't belittle me because I don't know or don't immediately understand the forumula that is 20 lines long. Please also refrain from telling me there was a thread discussing this 2 years and 9 months ago. I just want a simple explination for the following.


What would happen if we set up the following experiment?

One club placed in a clamp hanging upright so that the lie angle is level to the ground but suspended about a half inch off the ground.

One club just like the first, except that there is a mechanism keeping the clubhead from going forward (it can still go backward), and the clamp is twisted so that the shaft is already flexed considerably.

If we fired a golf ball at the clubface from off the ground parallel to the ground and straight at the middle of the clubface, what would happen to the ENERGY TRANSFER for these two situations?

My non-scientific belief is that the first one would have the shaft absorbing a good deal of the energy since it can vibrate freely, and reduce the energy that is maintained by the ball after collision. The second would have less energy lost into the flexing of the shaft and therefore the ball would maintain more of it's energy after the collision.

 

[Biffer]

Ringer,

Good question. It's possible to make assumptions regarding the outcome, but wouldn't it be best to do the actual experiment to discover the correct answer to your question?

 

[blehnhard]

Ringer - correct me if I am wrong, but approaching impact the shaft looks like this "(" not like this ")" - you are looking face on at a right handed swing going >.

Therefore, the idea that the "head" is trailing the shaft is not correct. The shaft is bent so that the "middle"of the shaft is behind the clubhead.

That is the "kick" to the shaft that results from the bending of the shaft in the opposite direction early in the downswing. This "kick" has no useful purpose as far as energy transfer is concerned, but is a timing feature built into the characteristics of the shaft to help determine loft and 'squareness' at impact.

I believe that the pressure of impact will actually rebend the shaft back the other way - very noticable when irons take a divot.

Again, I could be wrong.

Bruce

 

[golfbulldog]

http://www.youtube.com/watch?v=4MlhxXKTjMg

In this swing vision it seems to suport Blehnhard.

 

[Ringer]

This thread is not about whether or not the shaft flexes forward. I want to know the answer to the experiement because I am wondering about energy displacement/absorbtion.

 

[jmessner]

Well, from the physics I've read about impact, I think they'd be the same given the same effective loft angle. I'm basing that on the idea often discussed that the shaft is flexible enough in the short duration of impact to be ignored. That's why the mass variable in momentum equations for golf impact is used as just the clubhead mass and does not include the shaft.

 

[holeout]

Well, from the physics I've read about impact, I think they'd be the same given the same effective loft angle. I'm basing that on the idea often discussed that the shaft is flexible enough in the short duration of impact to be ignored. That's why the mass variable in momentum equations for golf impact is used as just the clubhead mass and does not include the shaft.

This seems to make sense. So perhaps we should be shooting the clubhead at the golf ball at X mph and see how it reacts, mph wise, after impacting the stationary golf ball?

 

[armourall]

Ringer, I think your assumption is correct, but are you saying that bending the shaft is the only way to prestress it? I believe the shaft can also be prestressed longitudinally, like pulling a piece of rope tight. (However the shaft, not being as flexible as rope, would be subject to being bent by the clubhead's COG seeking its inline condition.)

 

[Vicious Circle]

Ringer, consider frist the duration of impact vs the time it takes for the hit impulse to travel from the head up the shaft - stressed or not. From what I've read, the ball is gone before the impulse has gone much past the hosel area.

 

[Ringer]

Ringer, consider frist the duration of impact vs the time it takes for the hit impulse to travel from the head up the shaft - stressed or not. From what I've read, the ball is gone before the impulse has gone much past the hosel area.

So you think the two would react exactly the same? I just have a very hard time believing that. The clubhead would give, but there is something to be said about "effective loft". That makes sense but still doesn't explain where the ENERGY goes... and a ball rebounding would need as much internal energy maintained as possible. The less the club absorbs the energy, the better... I'm pretty sure a flexible shaft would absorb some energy and that would cause the ball not to rebound as far.

 

[shortgamer]

I remember someone saying once(maybe mandrin) that whether the clubhead was mounted to a shaft or a piece of rope the ball would travel the same distance if they had the same clubhead speed.

 

[Bronco Billy]

I remember someone saying once(maybe mandrin) that whether the clubhead was mounted to a shaft or a piece of rope the ball would travel the same distance if they had the same clubhead speed.

Hi There

Exactly...... What He is Looking for is Sustained Force During the Impact(Collision) Zone...... Guess What If there is Any It Ain't Significant...... The Collision Lasts 5 Ten Thousands of a Second and is 3/4 inches Long..... Now if You Think a Mere Mortal can do Anything Significant in this Collision Interval You are at the Very Least Naive...... As Trevino Says in the Commercial- If I Knew How to Do It I'd Tell You......

Cheers

 

[golfbulldog]

Hi There

Exactly...... What He is Looking for is Sustained Force During the Impact(Collision) Zone...... Guess What If there is Any It Ain't Significant...... The Collision Lasts 5 Ten Thousands of a Second and is 3/4 inches Long..... Now if You Think a Mere Mortal can do Anything Significant in this Collision Interval You are at the Very Least Naive...... As Trevino Says in the Commercial- If I Knew How to Do It I'd Tell You......

Cheers

Highlights by me

the short duration of the impact interval is often used as a reason for explaining why the golfer can not exert any additional force on the ball. Whilst it is certainly true that the body can not react in such a short time period, isn't Ringer describing the altered state of the shaft as the means by which the clubhead is slowed down less at impact ie. the duration of time is immaterial - the shaft condition that is under debate is created prior to impact... ie transition through downswing to impact.

However...

Search for the Perfect Swing showed by using a hinged 2 wood that the clubhead acts as though it were a free moving body - hinge mounted in such a way that it would bend back at impact if the shaft were exerting any force on the clubhead. High speed photos showed no hinge motion at impact.

The shots with the hinged club averaged 215 yards ( 30 shots) whilst the normal equivalent unhinged 2 wood averged 220 yards. They concluded that the small difference in distance probably due to reduction in clubhead speed ( due to either extra weight of the hinge or the "wobbly" feel of the hinged club causing the golfers to "go easy" when swinging.)

So, although it appears unbelievable, it does seem as though the evidence supports the fact that the shaft does not have any additional force to add to the ball... it is solely due to clubhead velocity.... even though i type it i still don't quite believe it!

We instinctively think that a heavyweight boxer's punch moving at the same speed as a flyweight boxer's fist ( assuming same fist size/mass) will do more damage to your face because of the heavyweight's bulky body that seemingly powers the fist through your face... this may be true... but i think that Mnadrin and other physics people have said that the clubhead - ball collision is of a different scale and hence essentially immaterial ... debate goes on...

 

[matt kluck]

Formula for Downswing

Dear Forum Memebers,
I read with great delight when you are in the middle of a great discussion. I do not post much but certainly check on all of you frequently. Unbeknownst to me, my sister-in-law went by "ladygolfer" on another forum and the two of us started fooling around with mathematics and really enjoyed about five hours of golf talk. She studied "Mechanical and Nuclear Engineering" at one of our finer higher institutions of learning and has been a source of great information for me in the past. I did not know that she and Mandrin had a few discussions on another forum and thus my contribution to your cause.

Try this formula, use it, break it down or kill it, it makes no difference to me but if it helps then so be it.

W=lvl sinQ/r

W=Angular Velocity
V=Velocity (angle/time)
Q=shaft angle at the wrist to left arm
r=radius measured from the shoulder joint to the to of the golf club

Things to consider:
1. v=angle over time
2. radius is measured at address

Have some fun with this and enjoy.

Matt Kluck
PGA Master Professional

 

[jmessner]

W=lvl sinQ/r

W=Angular Velocity
V=Velocity (angle/time)
Q=shaft angle at the wrist to left arm
r=radius measured from the shoulder joint to the to of the golf club

Things to consider:
1. v=angle over time
2. radius is measured at address

Actually, the V is linear velocity measured in distance per unit time and W is radians per unit time. But, how is this formula related to the original question of shaft influence on impact dynamics?

 

[Brian Manzella]

Important

1. The shaft is timing mechanism.

2. The shaft assist the golfer in creating the proper impact aligments of the clubhead and clubface for the desired shot.

That's about all folks.

Since I learn that all this "heavy hit" stuff was bad math + false feel, and I figured out what to do with the information, my teaching has improved a bunch.

Next.

 

[daniell]

A clubhead attached to a shaft and approaching impact has a tensile force. A clubhead attached to a rope and approaching impact at the same speed does not have the tensile force.

Can someone explain to me how the two scenrios will hit the ball the same distance? Is that tensile force negligible?

BTW, like Brian says, all this maths won't make us a good golfer.

cheers,

daniel

 

[Ringer]

Ummmm, is it just me or is my original question still going un-answered? I am not putting the clubhead in motion with the experiment.... the BALL is in motion.

 

[DOCW3]

Purpose

Ringer~

It would help me if I (1) understood why this question is important to you and (2) what you will do with the answer assuming one is accepted.

 

[Vicious Circle]

So you think the two would react exactly the same? I just have a very hard time believing that. The clubhead would give, but there is something to be said about "effective loft". That makes sense but still doesn't explain where the ENERGY goes... and a ball rebounding would need as much internal energy maintained as possible. The less the club absorbs the energy, the better... I'm pretty sure a flexible shaft would absorb some energy and that would cause the ball not to rebound as far.

Yes they would react the same IMO.

Think about your last sentence for a moment. In your example, impact impulse travels up the shaft - then returns to the clubhead (which must occur if the clubhead/ball is to sense or be affected by anything about the shaft's state) where somewhat less energy is imparted to the ball due to shaft flex,,,

I don't have numbers but this return trip takes way too long compared to the impact duration of .0005 sec.