Understanding shaft "kickpoint" or "bend profile"

***cobalt*** · 04-23-2011, 10:42 PM

Originally Posted by cobalt

Maybe it would help if Visor and/or Dinkalot or Jumpsmash can explain to us all how one can accurately locate the kick point...

Thank you for your question, Cobalt. Our Technical Support and other Specialists are at present busy with other Customer Service issues, and will get round to your question in a short while. In the meanwhile, please visit this site for further information and assistance:
http://www.open2.net/diyscience/mangonel/index.html

-From the KickPoint Technical Support Team.

Ingest in jest...

**visor** · 04-24-2011, 12:33 AM

^^^

Lol!

From my understanding, the kickpoint or bend profile is not a static but a dynamic measure. Meaning you can't just bend the racket between your two hands to figure it. You actually have to hit hard with it to feel the flex point.

Having said that however, there are certain rackets with tapered shafts (technology borrowed from golf shaft design) that you can actually feel with your hand the separate joints of different diameter shafts as you run your fingers along the length of the shaft.

Eg Panda Power rackets are designed with not just one but several kickpoints along the shaft, by joining 3 pieces of shafts of decreasing diameter from the handle to the T. Eg starting with something like 7.0mm diameter at the handle, to 6.7mm in the middle, to 6.5mm at the T. The idea of this design is that the shaft will flex more along the length of the thinner shaft and the flex profile can be designed to better take advantage of power and to be more suitable for a wider variety of swing styles and speeds.

That's why the term bend profile is better to describe the shaft's dynamic behavior, rather than using kickpoint.

**jump-smash** · 04-24-2011, 12:33 AM

@visor
hello ... I'm glad that you open a new thread here
so we could discuss this interesting subject without being Out Of Topic

one thing about stiffness is that it is very difficult to measure without a proper machine
how could we confirm it just by using feeling because it is relatively different for every person
so it is hard to agree on the degree of stiffness even on the same racket
what may feel flex for some could feel stiff for others

furthermore the length of handle / cone and the shaft itself will contribute for more contradictions
not to mention the location of the Kick Point / Bending Point and also Balance Point.
the nearer the KP to the handle / cone it tends to feel more flex
and the further the KP is to the T-Joint it will feel more stiff
and also the more head heavy the racket it will make the shaft feel more flexible ...

**DinkAlot** · 04-24-2011, 03:25 AM

Originally Posted by cobalt

Apacs again. I'm surprised the handle didn't splinter as well...

Panda's an equal opportunity racket breaker.

Some of Panda's best breaks:

NS9000-X don't like 32lbs. miss...hits.

**daren2** · 04-24-2011, 03:37 AM

Originally Posted by DinkAlot

Panda's an equal opportunity racket breaker.

Some of Panda's best breaks:

NS9000-X don't like 32lbs. miss...hits.

Wow!!! i don't think i have the power to break any of them!

**j4ckie** · 04-24-2011, 04:14 AM

Holy smokes....The shaft cracks are incredible, really shows you use those rackets to the max

I think I dont want to be on the receiving end of your smashes anytime soon^^

**Sketchy** · 04-24-2011, 06:43 AM

The part about shaft flexibility is pretty widely accepted, I think.

There's no such thing as a "kick-point" - the shaft will flex along its entire length.
In fact, the "flex profile" will be exactly the same for all rackets having shafts of constant diameter and composition (ie. most, incl. all Yonex) - a stiffer/less head-heavy racket will bend less, but the distribution of flex will be identical.
eg. http://www.engineeringcalculator.net...alculator.html (click the 4th diagram down).

The only way you'll get a significant difference in flex profile is by using a tapered shaft, and although they're becoming more common, I believe the vast majority of people here are going to be using rackets with non-tapered shafts.
According to manufacturers such as Gosen and Kumpoo, the main benefit of a tapered-shaft is that it allows you to hit steeper smashes - this is because you can contact the shuttle higher whilst still having the face of the racket pointing downwards (because the shaft flexes more near the T-joint). There's also a benefit to control - a small amount of flex near the handle will cause much greater movement of the head, compared to flexing higher up the shaft.
It's not really about swing speed at all.

**jump-smash** · 04-24-2011, 08:34 AM

@DinkALot
I never saw so many rackets broken just because someone use them to play in my entire life
it's a different story if clashing the rackets
it is very rare to have that kind of POWER
I don't think that there's a racket strong enough for you to use

***cobalt*** · 04-24-2011, 09:28 AM

OT: Wonder if Dink plays baseball...
If he does, I'm glad I'm nowhere close to CA

**Naim.F.C** · 04-24-2011, 09:40 AM

DinkAlot are you Thor?

**DinkAlot** · 04-24-2011, 11:00 AM

@Sketchy: please check your e-mail.

Originally Posted by cobalt

OT: Wonder if Dink plays baseball...
If he does, I'm glad I'm nowhere close to CA

Yes, Panda used to play a little baseball and then a lot of softball traveling around the U.S.; was so fun until Panda blew out his throwing arm then even worse, fractured his back diving, colliding with the fence.

Panda's lucky to be alive.

Panda love's base and softball...almost as much as badminton.

Originally Posted by Naim.F.C

DinkAlot are you Thor?

No Sir. Thor is the God of Thunder. Panda is nothing but a nice, gentle, panda who dinks-a-lot on the court these days. Panda leaves the smashes to the young guns. Panda's too old to smash.

Originally Posted by jump-smash

@DinkALot
I never saw so many rackets broken just because someone use them to play in my entire life it's a different story if clashing the rackets it is very rare to have that kind of POWER I don't think that there's a racket strong enough for you to use

Panda's breaking much less rackets these days and is happy with his "improvement". Panda broke a lot more rackets back in the day; mostly do to poor timing, bad or miss...hits. Panda has minimized the miss...hits and much less rackets are breaking. But still, every month or so, a handle snaps.

But no worries, Panda has a bunch of spare handles and Gorilla Glue.

**visor** · 04-24-2011, 11:12 AM

And now after a few words from your sponsor,we're back to the regular programming...

Cobalt, in answer to your question.

Dink, does this sound right to you?

Originally Posted by visor

^^^

Lol!

From my understanding, the kickpoint or bend profile is not a static but a dynamic measure. Meaning you can't just bend the racket between your two hands to figure it. You actually have to hit hard with it to feel the flex point.

Having said that however, there are certain rackets with tapered shafts (technology borrowed from golf shaft design) that you can actually feel with your hand the separate joints of different diameter shafts as you run your fingers along the length of the shaft.

Eg Panda Power rackets are designed with not just one but several kickpoints along the shaft, by joining 3 pieces of shafts of decreasing diameter from the handle to the T. Eg starting with something like 7.0mm diameter at the handle, to 6.7mm in the middle, to 6.5mm at the T. The idea of this design is that the shaft will flex more along the length of the thinner shaft and the flex profile can be designed to better take advantage of power and to be more suitable for a wider variety of swing styles and speeds.

That's why the term bend profile is better to describe the shaft's dynamic behavior, rather than using kickpoint.

***cobalt*** · 04-24-2011, 12:07 PM

Something bothering me at the periphery of my thinking; also something that Sketchy said; maybe I won't be able to express it adequately, so bear with me...

Lets say my grip doesn't change in the following 2 cases.
1. If I smash using constant acceleration, and
2. If I smash using higher acceleration and sudden deceleration
Would I in effect, "feel" different kick-points on the same racquet? Would the racquet actually "behave" differently?

I would think that stresses on the shaft section close to the handle would be magnified in the second case.

**visor** · 04-24-2011, 02:08 PM

Originally Posted by cobalt

2 cases.
1. If I smash using constant acceleration, and
2. If I smash using higher acceleration and sudden deceleration
Would I in effect, "feel" different kick-points on the same racquet? Would the racquet actually "behave" differently?

I would think that stresses on the shaft section close to the handle would be magnified in the second case.

That sounds right. That's probably how Dink breaks so many shafts, nearly most of them near the handle.

That's why tapered shafts are designed like a whip, with a thicker section closer to handle for solidity and a thinner section closer to the tip for acceleration and speed.