Comments below *** ----- Original Message ----- From: "Al Taylor" <[EMAIL PROTECTED]> To: <[EMAIL PROTECTED]> Sent: Thursday, January 02, 2003 3:16 PM Subject: Re: ShopTalk: shaft flex v.s. frequency
> Lloyd, > I am not sure about the effect caused by the loading at the top of the > swing, and let others deal with that. You make my original point > below. The pro accelerates into impact, thus holding the toe in a constant > and in the case of pros, consistent location relative to the ball. Eg. > they are very consistent and have few off center hits. The amateur has a > tendency to decelerate before impact. If he decelerates the toe will come > back up giving you the "bob" of dipping and then raising. My guess is that > once you stop accelerating, the toe will tend to unload or come back to > neutral and probably oscillate/vibrate about the neutral > position. *** No, because the clubhead speed is not reduced and the centrigugal force pulling down is still there. Any deceleration that I have seen reduces the clubhead speed less the 10% so even then you have a high percentage still pulling down. Decelerating before impact would only exaggerate this. How did > I do on this? *** From all the swing data I have gathered which shows the clubhead speed and acceleration upto impact less then 10% of all players tested showed any sign of deceleration. > > Al > > At 08:07 PM 1/2/2003, you wrote: > >Al > > > >When you talk of toe bob I think of an oscillation. As club head speed > >builds during the swing (yes speed is a result of acceleration, > >accelerating, speed gets higher, etc) the centrifugal force in this case > >progressively gets higher during the swing thus creating a load pulling down > >on the head that progressively gets greater until ball impact at which time > >the club head speed drops abruptly. So there is no bobbing caused by > >clubhead speed prior to impact, the toe is only pulled down. But overlaying > >that deflection and the only bobbing action which occurs is from the toe up > >deflection induced at the top of the swing being released when the club face > >rotates into the hitting path. This later bobbing action is the only thing > >that will change the amount of recorded toe down deflection at the time of > >impact and it is independent of clubhead speed. Two players using the same > >club with the same club head speed just prior to impact can have different > >toe deflections only because of the induced toe bobbing from toe up > >deflection introduced at the top of the swing. This toe up deflection would > >be dependent on club position at the top and how much to club is loaded at > >the top of the swing. > > > >llhack > > > >----- Original Message ----- > >From: "Al Taylor" <[EMAIL PROTECTED]> > >To: <[EMAIL PROTECTED]> > >Sent: Thursday, January 02, 2003 1:27 PM > >Subject: Re: ShopTalk: shaft flex v.s. frequency > > > > > > > Lloyd, > > > Thanks for the reply. I think that head speed has a direct bearing on the > > > centrifugal force that pulls the toe down, into the first half of a > > > "bob". If I am wrong, stop reading, because I am basing my comments on > > > that. If it is true, then I would make a layman's guess that by either > > > increasing or decreasing the head speed would cause a change in the amount > > > of toe bob / deflection. I always thought the acceleration and > > > deceleration was changing speed. What am I missing? Thanks again. > > > > > > Al > > > > > > At 06:10 PM 1/2/2003, you wrote: > > > >Al > > > > > > > >Acceleration through impact would have nothing to do with toe up toe down > > > >deflection its the centrifugal force pulling down on the head and the > > > >flexing of the shaft in the toe up toe down direction initiated at the > >top > > > >of the swing. These deflections are normal to a players acceleration at > > > >impact. The acceleration component normal to the toe up toe down flexing > > > >would have no or at least very little affect on toe up toe down > >deflections. > > > >The fact that the good player takes the club away from to top slower or > >more > > > >smoothly would substantially reduce that component of toe bob which I > > > >believe is the major factor in the toe deflection problem. > > > > > > > >llhack > > > > > > > >----- Original Message ----- > > > >From: "Al Taylor" <[EMAIL PROTECTED]> > > > >To: <[EMAIL PROTECTED]> > > > >Sent: Thursday, January 02, 2003 10:16 AM > > > >Subject: Re: ShopTalk: shaft flex v.s. frequency > > > > > > > > > > > > > Lloyd, > > > > > I hate to argue with an engineer since I am out of my league then, but > >I > > > > > believe that the TT shaft lab results do show that higher head speeds > >have > > > > > greater toe down. Along this area, the Pros usually are still > > > >accelerating > > > > > into impact and, as a result, have little to nil toe bob. The amateur > > > > > often starts to decelerate prior to impact and the toe then starts > >back > > > >up, > > > > > or bobs. The TT graphs show that somehow there is often a series of > >toe > > > > > ups and toe downs on the later example. > > > > > > > > > > I know that my irons profile is similar to pro iron profiles (wonder > >why > > > >my > > > > > shot results aren't the same?) but my driver shows some toe bob. > > > > > > > > > > Al > > > > > > > > > > At 09:40 AM 1/2/2003, you wrote: > > > > > >Royce and Alan > > > > > > > > > > > >The centrifugal force is certainly part of the Toe down deflection at > > > > > >impact. Since toe down deflection is dependent on club head speed > >this > > > > > >would make the better players with the high clubhead speeds have > >greater > > > >toe > > > > > >down deflection ( opposite True Temper results ). What I described > > > >earlier > > > > > >is the other component of toe down defection at impact. As can be > >seen in > > > > > >all of the Shaft Lab data there is initially a toe up deflection at > >the > > > >top > > > > > >of the swing. This deflection along with the time from the start of > >the > > > >down > > > > > >swing to impact gives the shaft time to go through 1/3 to 2/3 cycle > >of > > > >its > > > > > >natural frequency resulting in some degree of toe down deflection. > >This > > > > > >resulting defection is a function of how much the club is loaded at > >the > > > >top > > > > > >of the swing to produce the initial toe up deflection. Herein lies > >the > > > > > >difference between the good player and the others. > > > > > > > > > > > >Allen, I follow your 1/2 cycle argument and our only difference is in > >the > > > > > >definition of the cycle. As an example, if I mount the club in a > > > >frequency > > > > > >analyzer and pull the head down and hold it in that position before > > > > > >releasing it, it dose not complete a full cycle until it returns to > >the > > > >max > > > > > >down position again. A 1/4 cycle would bring it to shaft straight > >with > > > >max > > > > > >upward velocity. As in the swing I do not consider the loading of the > > > >shaft > > > > > >as part of the cycle because it is not a function of natural > >frequency or > > > > > >spring properties. > > > > > > > > > > > > > > > > > >----- Original Message ----- > > > > > >From: "Royce Engler" <[EMAIL PROTECTED]> > > > > > >To: <[EMAIL PROTECTED]> > > > > > >Sent: Tuesday, December 31, 2002 10:07 PM > > > > > >Subject: FW: ShopTalk: shaft flex v.s. frequency > > > > > > > > > > > > > > > > > > > Alan said.... > > > > > > > > > > > > > > <snip> > > > > > > > As far as 'toe bob' goes I am not sure that I know what you mean > >by > > > > > > > this. I think it is probably the toe down deflection of the club > >head > > > > > > > caused by the centrifugal force on the offset cg of the club head. > > > >This > > > > > > > force increases very rapidly near impact (it's proportional to the > > > >square > > > > > > > of the head velocity) and is resisted mostly by a relatively short > > > >section > > > > > > > of the shaft near the tip. > > > > > > > > > > > > > > </snip> > > > > > > > > > > > > > > As I understand it there are two forces acting here, both the > >result > > > >of > > > > > >the > > > > > > > CG of the clubhead being offset from the centerline of the shaft. > > > >First > > > > > > > there is a moment working to align the CG of the clubhead with the > > > >shaft, > > > > > > > which has the effect of rotating the trailing edge of the clubhead > > > >under. > > > > > > > This has the effect of increasing the loft of the club as it goes > > > >through > > > > > > > the ball, and acts in the plane of ball flight, commonly called > > > >dynamic > > > > > > > loft. According to Tom Wishon's book, moving the CG 1/8" further > >back > > > > > >from > > > > > > > the face will add about 7 feet to the trajectory. > > > > > > > > > > > > > > What is commonly called toe bob is the result of a similar, but > > > >orthogonal > > > > > > > moment trying to align the CG of the club with the shaft in the > > > >direction > > > > > > > from the toe to the heel. The net effect is to rotate the toe of > >the > > > >club > > > > > > > around the CG, which bends the tip towards your toes i.e. in a > >plane > > > >that > > > > > >is > > > > > > > orthogonal to the plane of ball flight. This is the effect that > > > >causes > > > > > > > dynamic lie angle to be different from static lie angle. > > > > > > > > > > > > > > All of which combines to make it amazing to me that any of us can > >ever > > > >hit > > > > > > > the ball "on the screws".... > > > > > > > > > > > > > > Royce > > > > > > > > > > > > > > > > > > > > > > > > >
