String Tension and temperature change

[DinkAlot]

Spam! postings from tanepak!

LOL! What's this world coming to? Who would have thought Eepak spamming.

[Matt]

LOL! What's this world coming to? Who would have thought Eepak spamming.

Yeah beats me. Either taneepak got internet issues about his post not showing up on his or was intentionally doing it. In either case, the moderators would not like to see that kind of action on the forum as it goes against the rules for spamming.

[DinkAlot]

Yeah beats me. Either taneepak got internet issues about his post not showing up on his or was intentionally doing it. In either case, the moderators would not like to see that kind of action on the forum as it goes against the rules for spamming.

Matt: take it easy, I'm just joking. Eepak wouldn't knowingly post all those times. Even if he did, we should just leave it up to the Mods, not a big deal.

[BaddGolfer]

lol tanepeak, you had to post it 3 times?

As I said it's not mine my rating system.

I still have not gotten an explaination why speed 78 flies noticably slower in warm air at the temp when the facility raised up the temperature, then compared to when it's at the normal cooler temperature when it does fly at the proper speed. That's pretty much the piece I'm most interested in. This is because is a counter example where the proper rating system does not explain.

I also think of it in F1 perspective. More down force the car has, the slower the car would be because there is more weight generated, with increased drag which results in a lower top speed. With less down force, the car will be faster because of less weight generation and it can obtain a higher top speed.

Matt, if you are talking about the same shuttle behaving that way, then please note the two temps and humidity readings. Theoretically its possible, when the heater is turned on to raise the gym temp, the humidity went down and dry air is more dense than humid air. I am not sure if the change in humidity is so much to more than offset the temp increase. I never played in a heated gym, so I have no first hand experience on this...

[BaddGolfer]

AH I SEE. Thanks, u solved this riddle of mine which had bugged me for a long while. This barometric thingy (not metric at all) is meant for weatherman making their little isobar map. It is a calculated number , NOT MEASURED.

"imagine if each stations bored a hole straight down to sea level, lowered their pressure sensing device to the bottom of the hole, and obtained readings. This is the sea level barometer."

so, reading barometric pressure has less meaning to me now. It explains why before i keep seeing vancouver and calgary pressure are so similar, and often calgary barometric pressure is even higher than vancouver but yet van. is at sea level. The confusing part weather report listed them as 'Pressure', and not barometric pressure. Barometric pressure is quite useless for the average joe public.

The next thing for you to figure out is the effect of the difference in gravity at high altitude locations!

[Matt]

Matt, if you are talking about the same shuttle behaving that way, then please note the two temps and humidity readings. Theoretically its possible, when the heater is turned on to raise the gym temp, the humidity went down and dry air is more dense than humid air. I am not sure if the change in humidity is so much to more than offset the temp increase. I never played in a heated gym, so I have no first hand experience on this...

Yes, this is assuming the same shuttle. Maybe you can ask the facility where you play to raise the temperature up for a while then turn it off as a test. Then the shuttle out, you may notice what I was observing.

[BaddGolfer]

Yes, this is assuming the same shuttle. Maybe you can ask the facility where you play to raise the temperature up for a while then turn it off as a test. Then the shuttle out, you may notice what I was observing.

I don't think my facility has heating (atleast I've never seen them use it). Many times in winter, I don't even take off the warmups...

[taneepak]

Sorry about the multiple posts due to one of two trans-Pacific cables being damaged by Taiwan earthquake. All internet communications in this part of the world adversely affected.

[DinkAlot]

Sorry about the multiple posts due to one of two trans-Pacific cables being damaged by Taiwan earthquake. All internet communications in this part of the world adversely affected.

This is true, as of right now, all these websites are down:

www.puppysports.com
http://www.bbesports.com/

[taneepak]

I also think of it in F1 perspective. More down force the car has, the slower the car would be because there is more weight generated, with increased drag which results in a lower top speed. With less down force, the car will be faster because of less weight generation and it can obtain a higher top speed.

Downforce and lift in cars and F1 racing cars are due to pressure differences. They do not make the same car heavier or lighter, although the downforce or lift seems to give one that feeling. In F1 cars the amount of downforce can be manipulated using the "wings". It can be made to have more downforce in sharp corners but almost very little in a straight, but that car still weighs the same. As a matter of fact you can make your ordinary road car to have more downforce. Just come up with some wings to channel the air flowing under the car so that they don't go all over the exhaust, tubes, etc at the bottom of the car, in such a way that more air comes out the back than what goes into the front underneath the car. It does this just like a plane, pressure differences to lift for take-off and pressure differences to slow down landing speed, and all these without adding or subtracting any passenger or cargo.
With shuttles, we use different weights to push through the air, although some fine adjustments to speed can be made by tipping the feathers, inwards or outwards.

[silentheart]

Hi Matt,

F=M*a. Even the down force makes the race car feel weight more. The mass is still the same. Therefore acceleration is still the same if you put same force. Also, because the care has moredown force, it give more traction and therefire corner at higher speed and tires are less chance to spun out and actually accelerate better.

However, this is totally different compare to the shuttle.

[Matt]

Well when I was explaining, I was only referring to the straightline speed only, not the cornering part, even thou yes it also plays a role there. The proper downforce setup is also needed as well because they have to take in both consideration the corning and straightline speed.

Sometimes when I watch F1 in qualifying session live, watching the same car doing adjustments to reduce the downforce proven to be better at times. The car appeared to be less stable on the corners, however the straightline speed made up for it for the car to get a better track time compared to when it had more downforce. Evidence would be looking at the speed traps.

[cooler]

Matt, if you are talking about the same shuttle behaving that way, then please note the two temps and humidity readings. Theoretically its possible, when the heater is turned on to raise the gym temp, the humidity went down and dry air is more dense than humid air. I am not sure if the change in humidity is so much to more than offset the temp increase. I never played in a heated gym, so I have no first hand experience on this...

a minor clarification is in order.
Yes, raising the temp. of humid air will make the air dryer but not denser since this same air is now warmer. Pressure and temperature have bigger influence on air density than level of humidity.

[hydrocyanic]

I must be in the wrong place...

though I distinctly remember clicking on "string tension and temperature change"

though, to strick to the current 'topic' I remeber from chemistry gasses get more dense when they cool down...(try cooling down water vapor)

exception is, offcourse, water. if you freeze water it gets less dense, but this is because it forms hydrogyn-bridges...the molucules stand further apart.

I think humidity is the key factor, because 'hot air' absorbs more moisture...wait, that might make it more dense...hmmm, how contradicting

i will just add some white wine to the table then...

water is most dense at 3degree C(i don't live in the state :P )

[CoolDoo6]

There was a cold snap in London last night. Approximately -1 celsius on the outside. There was light ice on the puddles. Indoors, my MLXL at 15 lbs tension was completely unaffected. It was at full power and very nice. However BG65, PG65, and Gosen Nano coated strings at 26 lbs were all popping like crazy. I picked up 5 rackets for restring in one night. As I strung these rackets previously, it was somewhat embarrassing for them to all go at the same time. Although the racket owners all insisted on paying the full restring price, I will be giving them a one off cold-snap discount anyway.

Low temperatures are definitely bad for strings and stringer reputation.

[taneepak]

Very high string tensions and very thin strings are for the tropics only. If you live in much colder countries you can still enjoy what the tropics boys and girls take for granted, if you are loaded and don't complain too much about frequent string breakage.