1. ## Physics Coursework

Ok
Hey I am an A-Level physics student who plays badminton
My aim is to find the optimum string tension for maximum rebound velocity.
I need also to know the best level of tension in strings Since I've never had my racket restrung cos it's never broken and I don't know that
I'd really appreciate any insight you guys have on whether more tension is bad or good. What your 'favourite' tensions are.
Also is it good to have a high rebound velocity?
I'm sorry I've been playing a while but not well
Hopefully you guys can help!
I'd appreciate it!
Thanks!
GreysGirl

2. Dear GreysGirl,
1) Welcome to BCBF.
2) What is an A-Level physics student? Are you a college or university student?
3) There are too many factors to consider. I would almost consider this as a loaded question.
4) Every one has their own favorit string base on their need. Everyone's need are different.
Please be more specific on the given factors. For example, a string player swing fast (or weak player swing slow). A racquet with stiff shaft (or flexible shaft). A head heavy (or a head light racquet) What type of shots (smash, clear, net drop or long drop.)

Good luck

3. Hey, A level is what uk students do between 16-18. There are an awful lot of variables to consider here. If I were you I'd choose 1 type of string for a start. Then you'd need a lot of the same racket at different tensions. Then you'd need a decent stringer who can string all of them. This project could become very expensive very quickly just to warn you if you were to do it properly. Or you could use only one racket and collect one set of data then restring, I guess that would be cheaper
I did mine using water rockets, so I think if you think about this and are careful it will be possible, though it may become expensive.
Hope that helps!

4. If you consider the racquet at impact, you have an impact force at the head from the shuttle that causes a bending moment opposite to the direction you are swinging. However, we know that with a decent stroke the head does not jump back at impact, so there has to be an equal and opposing moment generated from the grip end of the racquet.

With a stiffer stringbed you'll have a sharper rise in impact force meaning a shorter impact time is necessary to transfer the same amount of energy. A higher energy/time ratio means more power, which is good. However, this also means that you have to generate force at a faster rate at the grip. At some point, the impact is too great for you to handle appropriately and the excess force is transferred into your hand and wrist. Anyone who's used a string that too stiff knows that it can hurt when you swing it hard.

5. ## Everyone has their own favourite strings tensions based on their needs

Originally Posted by GreysGirl

My aim is to find the optimum string tension for maximum rebound velocity.
I need also to know the best level of tension in strings...

What your 'favourite' tensions are. Hopefully you guys can help!

.
Hi GreysGirl,

Perhaps you could get some insight if you read these 2 threads located at:

And what silentheart has replied is true ... Everyone has their own favourite strings tensions.

.

6. The best rebound 'should' come from
• A shuttle being smashed.
• Very tight string tension, 32lbs
• A very thin string.
• A central sweetspot hit
But these may be argued with, but power can be generated from a low tension racquet with an off-centre hit aswell.
As somebody has said there's a lot of variables and preferences.
Good luck with your coursework though.

7. On BC you get very different questions for "ideal string tension" "ideal string thickness" etc etc.

If I were you, I'd devise a Lab-test. Lock out as many variables as you can. (maybe even switch from a shuttlecock to a 5-gram pingpong ball, or something round of similar weight to a birdy).
Your answer may not have a real-time aplication for the sport, but this is what you would expect (with personal preferences being so diverse, and many many independent variables)

Calculating this with basic physics is very difficult... because it'll probably be all about energy-transfers. And the initial forces are already complicated enough: a birdy deforming, strings deforming, shaft flexing, sounds produced...
That's one heck of an asignment, I know mechanical engineers who would have difficulty with it

8. Oooook
It is a lab based test
I have a frame and i'm hanging weights off the end of the strings...
I'm using the cork from a shuttle and light gates.
I'm not really looking for real time application really
I'm just dropping the cork on the strings and recording rebound velocity.
However i need something to put in my rationale about goods and bads of string tensions and stuff so even your own personal preferences is fine
I'm sorry to be a bother and not very well explained but i have a million things on and this is not the hardest
You seem like lovely people and thank you for your help so far if you could bear with me for a little longer i would appreciate it

9. Since you are only testing the string and string bed. That is a good start. At lease you narrow down your variables.
1) now you have 3 variables to consider. a) string tension, b) string thickness, c) string material.
2) You need to go out and buy a cheapest racquet you can find.
3) Cut it into 4 sections so you have 12 grommets for mains and 12 grommets for cross.
4) Mount the racquet on a adjustable platform so you can adjust the main and cross tension. (Yes, I have a design of the platform by Yonex engineers. But you should figure one out yourself)
5) String up and tension the frame with string type 1. Test the bounce with different tension by adjust the platform. Repeat the same procedure with string type 1 with different thickness.
6) Repeat the same procedure 5 with string type 2.
7) You will get a set of data for you to do a statistic analysis.
Good luck and no more help from me now...

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