Results 35 to 51 of 134
05-30-2013, 11:07 AM #35
05-30-2013, 11:11 AM #36
Lol... yeah, but at least we got a good output to input ratio.
Does the software need an input for frame rate? Because that FHF super slow mo section is very very high frame rate per sec. Meaning that one frame is probably like 1/1000th of a sec.
05-30-2013, 11:24 AM #37
Lol, Yeah it is clearly not FHF real time.
Tried to do quite a few things with regard to frame rates but to no avail. If the video is already in slo mo you can't input the frame rate of the vid into the software for translation, not that i would know what the fhf frame rate is(or maybe you can I don't know the software inside out and there is developer templates). But you can imagine whatever speed he usually hits the shuttle and divide it by 1.5 to get the real time racket speed.
05-30-2013, 11:42 AM #38
have you incorporated air resistance in your calculations then? if you have been ignoring it, then why not ignore it further?
and it also depends on how hard the shuttle is being spun, if there is any slice component incorporated in the smash, the spin contributes.
05-30-2013, 12:01 PM #39
05-30-2013, 02:02 PM #40
I think if you want to compare what racket weight is best, you would be best forgetting about using a shuttle, and just record swings speed of only you(personally) seeing how fast you can swing the different weighted rackets, then use line and lengths formula!
05-30-2013, 02:13 PM #41
05-30-2013, 02:29 PM #42
05-30-2013, 02:45 PM #43
But still, let's say I swing fastest with the Arc FB, that doesn't mean that I'll get the fastest smash with it as it has a really low m. Otherwise you'll see everyone using very light rackets.
Somehow m also plays a large role eg for LCW, LD.
05-30-2013, 04:51 PM #44
So for instance lets say you have a racket with a 35g head mass and can swing(record it) at 150mph (67.05m/s) and then you get a flashboost with head weight 28g and you can swing that 170mph(75.99m/s)(record this).
Then use vs/vr=(c+1)*mr/(mr+ms) to see what has worked out best for you. (I think c is more 0.7 and a 5g shuttle)
first racket: the 35gram one
Vs/67.05= (0.7+1)*0.035/(0.035 + 0.005)
Flashboost one: the 28 gram one
vs/75.99 = (0.7+1)*0.028/(0.028+0.005)
vs = 109.6m/s (245.16mph)
So if you can swing that 28g that faster than the 35g one then hey presto!
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05-31-2013, 06:03 AM #45
05-31-2013, 06:31 AM #46
It's too simplistic a model anyway. Just because you can swing it with a lot of momentum, doesn't mean you'll be good at transferring it to a shuttle.
05-31-2013, 06:34 AM #47
05-31-2013, 07:32 AM #48
Whilst the vast majority of us (myself included) will only ever achieve a string-bed-speed of 20-30m/s, a speed in the region of 67-75m/s was probably needed to set the 421kph record.
Re: wind resistance. I was trying to find a formula to solve: a = -k.v*v, v(0) = V. Maclaurin series diverges too quickly to be useful. Anyone know a good method? If there is one, craigandy could plot several frames after impact and work back to what the contact speed would have been. That said, taking the average speed over the first 2-3 frames after contact will be within a few percent.
Re: momentum transfer to the shuttle. Whilst no contact is instantaneous, this one is short enough for additional force at the handle to make no significant influence what-so-ever. Just watch super slo-mos of balls striking cricket bats or snooker cues. The supposedly rigid timber wobbles like a tuning fork! To get the best shuttle speed for the weight you have, the velocity of the racket head needs to be as square to the shot as possible (no slicing) and as quick as possible at the point of impact.
05-31-2013, 02:34 PM #49
general approach with short/long time approximation equation:
matlab: in 2d for golfball with drag
06-01-2013, 02:09 PM #50
06-01-2013, 02:13 PM #51