How much do you pump up your kite?

Kite questions, info, feedback and tech discussion.
defever
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Today I learned something about the kite and the air in the struts.

Today I went out and got my kite washed up by the shore dump. Well, it needed a wash so I wasn't bothered (other than having a fricken' heart attack fearing that I destroyed my kite!). I got it recovered and the kite was floppy. OH SH!7. OH MY MONKEY BUDDHA. that's it. It's gone...

But I checked the leading edge and all the struts and I couldn't find the leak. So I asked one of the guys and he told me that sometimes the kite feels deflated when dropped due to the temperature difference in dry and wet. Makes sense. Cold air = less pressure, warmer air = more pressure.

So I carried on. With a jellyfish kite. Got washed up few more times, but it was fine. Same old jellyfish kite. No leak.

When I took the lesson in June, I was taught to pump up the kite until it feels firm on the leading edge and when the wing tips are hard to bend. No more, no less. I've been following this until now.

Having experienced this today, what do I do? Do I pump it up extra hard in anticipation of cold air compression and risk bursting the kite if I crash it hard)? Or is this down to personal preference of how soft / hard the kite should be?
broraboyan
Posts: 268
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I always pump it up until the strut is firm, if you flick your finger against the leading edge you should get a nice ping ding, I use this method for all my kites.
tadaska
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if it went soft from getting wet then surely it should soon dry out and go hard again?
defever
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oh yes the ping tip. I forgot about that... have you ever experienced this though, broraboyan?

Tadaska, that's what I thought too. That's why I didn't pump it up after it went floppy. In the summer I guess the kite can heat up with the sun. But in the winter I think it's harder for the air in the kite to heat up (already cold outside air + convection through flying).

I'm going out again tomorrow so I'll pump it up until I can hear the high pitch and see what happens. Hopefully I won't let the shore dump suck my kite like a fat kid annihilating a lolly pop...
southseasailor
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Low pressure? if the kite got wet then its most likely the air within contracted (shrank) which would result in a floppy kite. Don't forget, if the kite gets wet and flying again, evaporation will cause the tube to cool.

I know some folk use a gauge when inflating their kites, I used to till the adaptor broke. Pump up till its hard, wait a bit to get your breath (if your unfit like me) then give it another pump or two.
anthonylanglands
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Ok pump your kite till the pump feels like it wont go anymore .. period.
if your kite got smacked in the impact zone it lost air thru the values as they distort under alot of pressure and air escapes out the sides
cesc21
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A floppy kite is more likely to fold on you when jumping or eventually be difficult/impossible to relaunch.

The temperature difference doesn't sound that likely to me. More likely it's a slow puncture, which you can check by pumping it up at home, clip off the struts from the LE and see which part goes soft. Alternatively, pump it really hard, get a garden plant sprayer with some washing up liquid and water, spray all over LE and struts and check for bubbles. That way you can find the approx location of the leak before getting the bladder(s) out to fix them.
broraboyan
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defever wrote:oh yes the ping tip. I forgot about that... have you ever experienced this though, broraboyan?

Tadaska, that's what I thought too. That's why I didn't pump it up after it went floppy. In the summer I guess the kite can heat up with the sun. But in the winter I think it's harder for the air in the kite to heat up (already cold outside air + convection through flying).

I'm going out again tomorrow so I'll pump it up until I can hear the high pitch and see what happens. Hopefully I won't let the shore dump suck my kite like a fat kid annihilating a lolly pop...
yes I have, and what I found was it had a leak, tried to sort it 4 times and gave up after the kite losing shape and then catching the wind again when coming ashore of the beach not nice.so I sent it to Jonnie Eisler.sorted :grin:
defever
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oh no... I refuse to believe that it has a leak! oh my...

I checked the strut clips after I pumped initially and checked again after it crashed and the clips were closed so I believe, if it is leaking, it's the leading edge... humph.

With the wind we're getting on the south coast I'm not going to be taking it out for a while. But I'll see what the outcome is!

Thanks everyone for your advice, very much appreciated!!
southseasailor
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If it is the LE bladder, its not such a hard job to sort out. Youtube has some good clips on how to remove and refit. I have done it and all it takes is patience.

Check, before you go too mad, the tubes from LE to struts, could be a slight leak on a joint?
ali
Team/Shop Rider
Team/Shop Rider
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i would totally agree that its the cold water. especially on a sunny day, the airtemp can be alot warmer than the water temp, causing the air to contract, making the kite feel sloppy.

the opposite often happens in hot countries. People pump their kites up with a compressor (which is stored away in a shed or underground, meaning cold air) and then they leave the kite on the beach in the baking sun, and BOOM, kite explodes due to the air pressure increasing.
cesc21
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Of course temperature difference effects pressure, but (assuming you were in the UK!) the air temp certainly wasn't warm on Saturday and the sea isn't that cold yet, plus it went 'floppy...jellyfish' which sounds pretty deflated, more than just feeling 'sloppy'; so I still think it's more likely to be a slow puncture and it only takes say 15 minutes to check.
southseasailor
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When I was first learning to kite I attended a course for a day down at Fareham, Hill Head. I helped a few people launch their kites, and at least 3 of them had not inflated their kites enough. Kite would feel a bit saggy, but they still flew the thing. If its not inflated enough and you bang it down on the water, it will cool and contract the air.

Try it on a hot day/warm water and what have you, spray some water on your skin and expose to the breeze...my, doesn't it feel cool:)

Of course, it could still be a leaky valve or a pinhole :shock:
anthonylanglands
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Omg ... he ditched the fookin kite in the swell and it got smashed ... it lost air thru the valve ( Or it has a pin prick in the bladder) . When the inflate valve is distorted it losses air , weather it has a non- return valve or not . Try it and see.
I see it happen every week with learners smashing powered up kites into the sea.
It also happens with older kites when the valve has become too large for the stopper ( by continuously ramming the pumps inflate valve to deep into the kites inflate valve and stretching it ) , but this can be fixed by heating up the stopper and using something to push up inside the stoppers core to increase its diameter.
One question thou , what kites ru flying ? model and year.
Also , being told no more no less is crap .. your kite is a aerofoil and its flight and relaunch capabilities are governed by the rigidity of the frame of that wing , it should be inflated until the pump will physically not offer you any increased return for your effort , to maximize the efficiency of the flight and relaunch of your kite
defever
Posts: 193
Joined: Fri May 10, 2013 11:46 pm
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Location: East Sussex

anthonylanglands wrote: he ditched the fookin kite in the swell and it got smashed
Thanks anthonylanglands for telling everyone what happened, but I didn't see you when it happened?? You must have been standing by the beach, watching me struggle to recover it from the shore dump. oh proper pointless assumption.

OTHERWISE, thanks very much for your comment, antonylanglands. I really do appreciate your time and effort to actually leave 2p worth of your wisdom for me (and all the forum readers). I really do. As it seems to happen in this thread, there are mixed opinions about how much to pump, what the cause can be for the jellyfish aftermath, etc...

After it happened (wasn't really a crash, it stalled and dropped, but caught in the shore dump), I checked the struts (the clips were still closed and struts were remained pumped), and the leading edge. I was touching the LE like a pervert, stroking it up and down, one of my ears close to it hoping (actually hoping not) to hear hissing sound for a good while. When I carried on, the floppiness didn't change at all until I called it a day and packed up about hour ago, despite having couple more episodes of kite being washed it up (stalled again). So I'm less convinced that it has a puncture; may be a very slow puncture. I can understand that the pump valve is plastic and can distort under stress, but I find it hard to imagine this (I'm not saying it is mechanically impossible to distort the pump valve, just hard to imagine an impact so severe to distort it). The thermal change via conduction and convection is more convincing to me; cooler water than air and breeze can make you feel chilly even in your thick wetsuit, no? At least my little brain is convinced. I could be wrong, I could learn something new.

I don't know yet if there is a puncture / leak on the kite. I haven't pumped the kite since that day and I won't be in foreseeable future. Maybe after this incoming storm leaves.

Thanks all again for your thoughts in this! The biggest kook in here (i.e. defever...) appreciates your shared knowledge.
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