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. Decelerating before impact would only exaggerate this. How did I do on this?
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 > > > > > > > > > > > > >
