so as the palne is taxing down the runway i realize i forgot to open the valves on the bladders..i tell the stewards it might explode(not good choice of words!!)..
oops!!! i mean...how do you explain kite baldders to someone...well she was good looking and being a bloke(me not her)...(always about sex)..i say it's like a big condom with a wink i my eye..she proceeds to throw me on the floor and brutalize me...well almost!!!! I'll get the boss she says instead...
so am at singapore airport getting escorted to my luggage to see what has happenend...looks in one piece but did want to blow up the kites in the airpoprt..so will know more when i arrive at kite holiday destination..(no not telling where)
and knowing my luck wind will be in ..swell will huge and my kite will be in pieces...haha..

sounds like you just caused a lot of trouble for yourself that was unnessecary.

off to the lady boys in thailand looser

mrjf said...so am at singapore airport getting escorted to my luggage to see what has happenend...

Someone had replaced your kite with 5kg of Mary Jane???? Same shtt you'd been smoking earlier!

Tuff crowd ay? [}:)]

You have entered yourself for goose of the week though.. Alex has been pinged so suddenly there is a bit of competition for the dias.

BTW you could have tried calling on your shoe phone for help, just to seal the deal. Either that or inform the hosty that apparently airline hostys have the highest incidence of STDs of any (legal) profession. Instant upgrade to 1st class? Maybe not.

Cant beleive Im wasting my time replyn t that crap !

What you want to do with them.

I guess you lose no matter what. If this is a true story then you are too dumb to draw breath. If it's a joke, it's not working.

Do any of you guys actually know how much different the air pressure is up there? and seriously who can get every bit of air out of your kite anyway? normally a lot of the air would come out once it was packed up and in your bag, assuming your valves are open, but if the valves closed a lot of air could still be inside it.

Sure it may not expand enough for it to "explode" but there could be a noticeable "inflation" of the kite while at high altitude but it will only go back to normal when you come back down.

To settle this debate i decided to do some calculations. Good practice for my exams staring tomorrow :S

Most commercial flights fly at about 3,000m above sea level. At this height the atmospheric pressure is about 3/4 of 1 atmosphere (76kPa) or what it is at sea level (where we spend most of our lives :D).

If the kite had 10cm^3 of air inside it when the valves were shut and this was at 1 atmosphere (~101.3kPa) (In other words, someone packed up their kite at the beach but shut the valves just before putting his kite in its bag).

Using Boyle's Gas Law, P1V1 = P2V2, Then

If, 101.3kPa x 10cm^3 = 76kPa x V2
Then, 101.3kPa x 10cm^3/76kPa = V2
Then, V2 = 13cm^3

This result isn't a huge increase and shouldn't make your kite explode. A fully inflated 9m C kite has ~110L = 110000cm^3 and it should be inflated to about 7 Psi (0.002kPa).

If, 101.3kPa x 110000cm^3 = 76kPa x V2
Then, 101.3kPa x 110000cm^3 / 76kPa = V2
Then, V2 = 146000cm^3

Thats an increase of 34.6L
Which prob would be your kite exploding as that is an increase of about 1.3x the original size. (But this is only if your dumb enough to put a fully inflated kite into the cargo hold on a plane)

(I take no responsibility for any idiots who actually try any of this to prove me right or wrong. it will be at your own loss of your kite.)

I found a picture that can show the effects of atmospheric pressure changing.

This plastic bottle was closed at approximately 2,000 m (6,600 ft) altitude, then brought back to sea level. It was crushed by air pressure. This is the opposite effect as to what kite would do when the valves are closed at sea level and it is taken up. A kite would expand. But it would then contract on the way down again.

qwerto said...
Besides flaunting your infinite wisdom of grade 7 chemistry (max respect) and showing us a crushed plastic bottle, what is your point?

Physics Qwerto.

MasterUWA said...


Most commercial flights fly at about 3,000m above sea level.

More like 10,000m, but I agree with the rest of your working.

qwerto said...



No, chemistry Tobes.

I vote Physics.

peanuticus said...

WTF are you going on about? why would a bladder explode when there is no air in it..

altitude if the bladders are closed off

Isn't it (V1 x P1)/T1 = (V2 x P2)/T2?

The temperature at 3000/10000m is usually pretty different to that at sea level so your calcs are probably a bit out aren't they (not sure out in which direction as I'm no scientist).

Boyle would be turning in his grave to see his law misused like this

fver said...

I have a similar bladder pressure issue when I boost too high...

I was wondering if anyone else wet themselves when boosting big.

(sorry someone had to say it)

MasterUWA said...

Do any of you guys actually know how much different the air pressure is up there? and seriously who can get every bit of air out of your kite anyway? normally a lot of the air would come out once it was packed up and in your bag, assuming your valves are open, but if the valves closed a lot of air could still be inside it.

Whoa! you got a lot of red arrows there. You should post in the Windsurfing section we love that sort of stuff.

But as you said, you don't have to have enough residual air to reinflate the bladder, only enough to over stress whatever container the kite is packed in. Stuff a partially deflated kite in a cardboard box, you're sure to get a bit of a pop on depressurisation.

No problem in assuming the temperature in the hold remains the same if T1 = T2 - Boyle is happy.

No problem in assuming the temperature in the hold remains the same if T1 = T2 - Boyle is happy.

Wouldn't the temp in the hold on the runway when the plane is loaded be a lot different to the temp in the hold at 30,000ft??