Z-force 2 is terrible, looking for a new heavy head

Stiffer racquets repel harder and stronger but require more strength and speed put into them in order to make power. Sounds like you need something a bit easier to play with, so I'd suggest grabbing a Yonex Astrox 77 3U. It's not very demanding and does a good job in every area of performance.

 

At 2:35 is where he explains racquet stiffness in an easy to understand way.

 

Alright, you're on your own, dude. Good luck with your search.

 

Racket shaft are not solid tube (exception to 100zz), there is hollow part inside. So slimmer shaft not always less material, it can be less hollow area inside.
Also carbon fiber, depend on how you wrap/roll it each other could result different stiffness on final product.

About how stiffness relate to power.
Stiffer racket had higher ceiling for max power due to its nature (stiff) when bended it will snap back harder. But to be able to bend it one require to had stronger swing. Yes the racket characteristic are the same but player attribute vary alot especially on non pro player.

For the lenght of racket, the standard actually not specific number but ranged number. My old Lining are shorter than my TK770. Longer racket gain abit more power & reach while shorter one excel at handling.

about the compact head. Its not mean to makes racket lighter but smaller head mean less area in contact with air upon swinging which mean less air drag resulting faster swing (tho not by much).

Last. Dont get eaten up by marketing word. Most of them are not highly complicated high tech stuff, but just simple logic but many times its not common for our daily life so we easily tricked.

 

Basically this is the point, thought I would not prefer the term harder, but faster would be better.
The issue with the stiffness of a racket is the time window in which the racket will release its stored power by speeding up the racket face. A stiff racket has a very small time window, but will produce an higher velocity, whereas a flex racket has a larger time window, but will release it with less velocity.

And here the player is important. Is the player able to load the racket just before releasing it and hitting the time widow perfectly to hit the shuttle when the racket face reached its max velocity ?

It is far less about power of the player, but about the exact timing. A pro player who trains 6 days , >4 hrs each day has perfected his timing, so that he is able to utilize this small time window of a stiff racket to generate really high racket face velocity. On the other hand most players with only 5-10 hrs training a week will have a very hard time to get the timing right. Misstiming will result in lower velocity and therefor a flexible racket which has a much larger time window, thought with lower max velocity, will generate higher velocity eventually when used by non-pro players.

You can generate enough power with a stiff racket by brute force, but this will exhaust you quite easily, so that your clears will get shorter and shorter after some time.

Therefor, beginners should start with a very flexible racket (most low budget rackets are already), intermediate to advanced should test out more stiff (medium) rackets, because they are able to hit the right time window much better. But (extra) stiff rackets are ego rackets for the majority of players. I doubt that any casual player or low league player will invest so much training time to manage a stiff/extra stiff racket other than using brute force.

 

Astrox 99 and 100 are by far really stiff rackets (100 zz is the stiffest yonex racket afaik), thought the low budget models might be more flexible.

As already said, the astrox 77 is the most flexible astrox racket, still medium flex and really nice to play. I use the 77 nowadays, thought I although own the older 88s (stiff) and 88d(extra stiff), but they are a lot harder to play with, so they are only my emergency replacement rackets .

 

Smaller head means less string surface means less air resistance when swinging it.

Regarding shaft stiffness, I think the easiest way to imagine the shaft is to see it like a spring. A soft spring is easy to bend and by that, to store energy in it that can be released once the spring snaps back. A hard spring can store a lot more energy, but it needs more force to be bent in the first place. But if you have enough force to bend it, it will give you more energy back once it's "unloaded". The better a player's technique and strength, the stiffer the shaft that he or she is able to bend during a smash swing and the higher the potential energy that the shaft can add to the stroke if everything works perfectly.

However, looking at the whole swing and stroke physics, this "shaft support" is just a small part of the whole kinetic chain and all things involved that define the smash power. A Fu Haifeng would still punch a hole through your belly with an AX77. So as others said, in the end it's always about finding the racket that in its entirety fits your swing and feels right to you.

"The racket chooses you!"

 

From the current lineup, thing that are Head heavy like ZF are 99 pro.
Below 99 pro, there is 88D pro.

Well, you had tried few of your friend racket, why not get the same racket your friend own in which you like the most.
Rather than im suggesting one or two which you might like it or not like it.

 

AX99 are head heavier than 100.
Also 100 had solid shaft (no hollow part inside) & the stiffest in current lineup.
About 99, the old 99 are stiffer & less friendly. The new 99 pro are easier to use compare to the old one.
& if 99 Pro are to Head heavy, you can go to 88D pro.

For Lining, you might want to look at N99ii or TC75 if you can find one. One of great racket, easy to use & great power.

 

First you've now discovered that others people's opinions of rackets including the manufacturers are bs from your experiment, congratulations
Second nobody can actually give you a recommendation since you have no idea what specs suit you. Head heavy, 3u, why's that then? Cos other people say so? You've already got one of those and its crap, cos of the smaller head? Really? So now you can't hit properly but you need a head heavy 3u and the larger sweet spot is going to make all the difference... ok
Third you are intermediate so why are you wasting your money and time on comparing these high end rackets. The only thing that won't dissapoint is a cheap apacs or similar, medium flex medium stiffness, medium balance, no way of going wrong. Even better stick with your current racket and learn how to use it better.

 

thinking about it, actually when im having Adidas P8 which also compact head, my accuracy not getting worst like 50% of my shot miss hit. Even with my long trusted TK770 sometimes im also miss hit like when im in bad position or getting to much excited from my opponent super bad return.

My only noticeable issue was when im doing slice shot, my timing are off many times. Well maybe coz the head are smaller or probably the swing speed are different coz P8 definitely faster than my TK770. But again time solve the problem.

My only issue so far are with AVP. Its to damn fast & light from my preference & ruin my timing alot tho it had normal frame size.