That’s very true. Winter is just is an indicator. Obviously if a hall is heated and therefore the temperature is similar to warmer conditions above 20 degrees for sure you could consider playing with a speed 77 shuttle after speed testing it. As far as I’m concerned our halls are not heated and I recorded 15 degrees last time I checked which is again just an indicator but after testing the shuttles the 77 were just way too slow. Not only you can confirm it after testing them but also when smashing or defending. In fact I ordered a tube of speed 79 shuttles to speed test them because at 15 degrees (and probably a bit less soon around January) in a hall technically we should use or at least give a speed test try to a speed 79 shuttle.
Temperature is not the only element affecting the speed of shuttle. Air humidity also plays a role too. So even in a heated gym, if humidity is not controlled (low), you still need a faster speed. In fact, heating usually dries air even further so it could be worse. There's a scientific research about shuttlecock's physics. Temperature and humidity effects are in the Appendix B. http://iopscience.iop.org/article/10.1088/1367-2630/17/6/063001#njp513625t4
Time to put my chem eng hat on! The variation in shuttlecock speed is almost entirely due to density of the air in the hall, which is a function of temperature and humidity. The results of the study (Appendix B) by @khoai show that a rough 10% decrease in air density relates to roughly 10% more distance. That is pretty significant - in the test results, that was a change of 30°C leading to ~1.3m of distance difference! The rough gist of the results shows ~10°C is about 40cm, which sounds reasonable based on our experience of shuttle speed selection. The second significant part of humidity, is specifically the humidity AT WHICH SHUTTLES ARE STORED IN (not the humidity of the hall, which just factors into the air density*)! The reason stated in the article is simple: feathers absorb (small) amounts of water, so the same shuttlecock with be heavier, and therefore fly faster, if stored in humid vs. dry conditions. The article says the difference between shuttles stored in 15% relative humidity (quite dry) vs. 92% RH is the difference of 0.3g, or THREE speeds of shuttles! Granted most people might see the difference between 15% RH (car boot) and 40% RH which was recorded at close to 0.14g - still a difference enough to make a speed 78 shuttle feel like a speed 77 if you store them in a garage! *If you want to see the effect of humidity on air density, see what we call a 'psychrometric chart': https://www.google.com/url?sa=t&sou...FjAKegQIBhAB&usg=AOvVaw11kjUmKKIG202E4sCSpTkx For example, dry air (15% RH) at 20°C gives us about 89.5 m3/kg, whereas 40% RH air is about 87.2 m3/kg specific vol (inverse of density). This shows us the humidity difference from dry to comfortable humidity is about 2.6% lower density, which as we know from above, is therefore about 2.6% faster. Similarly, if we look at temperature, going to 40% RH at 15°C gives us 84.8m3/kg, which is 2.8% increased density. We can quickly see how sensitive shuttle speeds are to changing hall conditions, and storage of shuttles, and why the speed test is required, even when using the same tube of shuttles in the same hall on different days!
If anybody tells you that he is used to his speed, but the speedtest indicates that the shuttle is too slow you can say "according to the rules..." and refuse the shuttle. They want to take advantage, but why should you accept it, when they are used to a subjective impression of speed which is not according to the rules? It's not your fault that they are conditioned to slow shuttles. I experienced quite often that too slow shuttles were commented by my opponent as a cheat that he didn't hit it full or perfect, but insist to tip the feathers. My answer is normally "Okay hit as long as you think you hit it right". In tournaments I use the rear doubles service line as reference and use the shuttles slightly infront or slightly past to it, to have the middle of both extremes. I also experienced people who want to tip shuttles which land slightly infront of the rear doubles service line. Best way is to not give up. Everybody should have a fair game and this include beside the calls also the right speed. Be persistent to such people. They get pissed off, but hey it's not your fault that they never learned play the right speed.
They do get pissed hehe. I try to explain and go by the book but I still play at a low level where most players aren’t very serious about it. Also even if I now beat most of the players at the two clubs I regularly play at, they still see me as a beginner as they play since years at those clubs and before I started, and surely look at me like I don’t know what I’m talking about but hey things can change and I did put to good use the latest advice of @Cheung which was to perform a high serve in case of a slow shuttle being used during a match and it was great! Totally killed a guy as he could really not clear properly to the back of the court and it made me practice my smash a bit hehe. Won by a decent margin and proposed again my 78 speed shuttles. It was different and we had a tight 3 setters and I explained it was just his slow shuttle and you know what, trying to take his side, it was easier to accept for him. He saw the slow shuttle put him at a disadvantage and that he played better with a shuttle adapted to the condition because he could clear back to back a bit easier. If I can convert a few of the players at my clubs to these shuttle speed rules that would be great .
I agree. IMO there is no rule of thumb when we need to play which speed. The speed test is the most accurate way and best arguement to determine which shuttle is the right one. I play the whole year speed 3 (Yonex) or 77. For tournaments in the warmer days I tip the feathers. But every decision is made after the speed test. In my training hall I can play them from autumn to spring without tipping. If you can't find the middle with the opponent, I normally ask for an independent player (not his club and not mine, no friend or in the same group or class. I prefer to ask a player one level above.). IMO life is too short to accept crappy reasons and be locked up due conditions whose rules my poisonous opponent make. I want a fair competition and this also include to accept and follow any rule. It isn't my fault that some people learned a binary hitting action with a 6kg factory job. 1:hit with everything you can bring behind it and pure strength or 0: not hit. It's also not my fault and task to play games with a modified shuttle just because they never learned to control their swing very well. They want to cheat to deliver a better performance while I should sacrifice everything and accept a breaking of the rules. Not with me.
I used to avoid high serves (wrongly) but I’m loving it now. Kinda enjoying the slower shuttles at the moment . But it does feel like cheating to win points taking advantage of a slow shuttle. When people don’t know about the speed and issues related to a shuttle that is too fast or too slow it is one thing but when they play purposely with a slow shuttle for example it is a little bit like cheating. Anyway thanks for the tips .
Actually, I see it as tactical rather than cheating. It's very often that we don't get a perfect shuttle and it's relative to what you are used to and also brand of shuttle. Once you experience playing in different countries, you realise the shuttle flies differently in different countries. In the HK championships (our sort of 'national championships' ), they use yonex AS40. One year, the shuttle was incredibly fast. I did the test and the shuttle flew out of the back of the court by three feet. The umpire (all have umpiring qualification ) said to me either you play or you don't ! They supply the shuttles so they just don't have the variety of speeds available. The next year, the same shuttles and speed were used and it was perfect. The year after, slightly fast again! In the end, if you want to play, you just have to adapt to different conditions. It's good practice to play with fast and slow shuttles as you never know what the conditions are when you go to a tournament. I think attitude to slow shuttles is a bit regional. In HK, we don't have a strong culture of altering the shuttle. Probably because halls have air-conditioning and conditions are more consistent. I also don't see it much in Malaysia or Singapore but I am usually playing without aircon there and the weather is consistently hot and humid. Whereas in Europe, people are much more worried about the shuttle speed. It would be interesting to check what the Canadians and Chinese in China do.
Note that shuttle speed is usually under the purview of the referee, not the umpires. Some tournaments would rather switch to a different shuttle speed than start tipping. Sometimes, the referee wants to acknowledge every change. Good referees record humidity and temperature in the hall over the tournament days so that they can step in before the shuttle speed becomes too fast/too slow (see §3.5.4 ITTO). So, really, your complaints should go directly to the referee. But if the shuttles go that far out during the tests, as an umpire I would immediately call the referee on my own. I have no doubts any umpire who'd just play on with shuttles that go over the baseline during the test would be given a stern talking to in their evaluation.
Interesting again to hear how different cultures adapt to a specific issue whether it be badminton or anything else.
Thanks. I will do that next time. Note, this is a local tournament that do not have the inventory of other shuttle speeds.
