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I like my kite to be hard, when it will explode?

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Re: I like my kite to be hard, when it will explode?

Postby t3rse » Thu Aug 14, 2014 3:36 pm

I pump mine up to sound like a loose snare drum. It has a definite pitch when I flick it (like maybe a middle G). I don't know how high the pressure is but it takes putting some real ass into it the last few pumps.

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Re: I like my kite to be hard, when it will explode?

Postby Topaz » Thu Aug 14, 2014 4:01 pm

9psi seems like a lot of pressure for a kite.

The manufacturer indicates in the manual the maximum pressure for the kite. And it depends on the size of the kite.

This is from the Naish manual:

INFLATION PRESSURE:
Smaller kites require greater pressure in the bladder to hold their shape. Below are recommended maximum pressures.
• 3m through 7m kites require a maximum of 8.5 psi or .57 mPa
• 8m through 11m kites require a maximum of 7.5 psi or .51 mPa
• 12m through 15m kites require a maximum of 6.5 psi or .44 mPa
• 16m kites require a maximum of 5.5 psi or .37 mPa
• Always inflate kite very firmly.
Note: Do not over inflate the kite struts or you may damage
the internal bladder.

That's obviously the pressure at the moment of pumping it. During the session, the actual pressure will change. A hard slam against the water will increase the pressure a lot. Years ago it was common to see a main bladder explode during the slam. Now I think they take the hit with no problem.

The pressure also changes with temperature. If the temp of the kite drops because of the kite getting wet (rain or fall), the pressure will go down as well and the kite will get softer and won't fly as well as with the right pressure. It will come back to normal when it gets dry again.

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Re: I like my kite to be hard, when it will explode?

Postby yuko » Thu Aug 14, 2014 4:09 pm

I often pump my VarialX to 11psi. It's a higher aspect ratio kite that needs a lot of pressure to keep it from deforming when it get's to the limit of it's range.

Just get a Gauge!

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Re: I like my kite to be hard, when it will explode?

Postby tautologies » Thu Aug 14, 2014 9:07 pm

MarianoMoll wrote:9psi seems like a lot of pressure for a kite.
The danger of saying what PSI one use (from the pump) is that the pressure meters on the pumps will show different measurements from pump to pump. The ideal I think is to have a pump...sort of calibrate to the pressure you want and then use that as a way to keep your pumping consistent.

I have a buddy who claimed 12+ psi...when I used my pump to see he was at about 8...its a huge difference.

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Re: I like my kite to be hard, when it will explode?

Postby edt » Thu Aug 14, 2014 9:09 pm

MarianoMoll wrote:9psi seems like a lot of pressure for a kite.

The manufacturer indicates in the manual the maximum pressure for the kite. And it depends on the size of the kite.

This is from the Naish manual:

INFLATION PRESSURE:
Smaller kites require greater pressure in the bladder to hold their shape. Below are recommended maximum pressures.
• 3m through 7m kites require a maximum of 8.5 psi or .57 mPa
• 8m through 11m kites require a maximum of 7.5 psi or .51 mPa
• 12m through 15m kites require a maximum of 6.5 psi or .44 mPa
• 16m kites require a maximum of 5.5 psi or .37 mPa
• Always inflate kite very firmly.
Note: Do not over inflate the kite struts or you may damage
the internal bladder.

That's obviously the pressure at the moment of pumping it. During the session, the actual pressure will change. A hard slam against the water will increase the pressure a lot. Years ago it was common to see a main bladder explode during the slam. Now I think they take the hit with no problem.

The pressure also changes with temperature. If the temp of the kite drops because of the kite getting wet (rain or fall), the pressure will go down as well and the kite will get softer and won't fly as well as with the right pressure. It will come back to normal when it gets dry again.
it's all about hoop pressure which depends on the diameter of the tube and the pressure, here's a helpful chart, assuming a new kite explodes with a rim stress of somewhere around 400 pascal of hoop stress these are all equivalent pressures:

6 inch diameter tube, 13.5 psi = 400 pascal
5 inch diameter tube, 16 psi = 400 pascal
4 inch diameter tube, 20 psi = 400 pascal
3 inch diameter tube, 27 psi = 400 pascal
2 inch diamter tube, 40 psi = 400 pascal


You can pump your 3m somewhere around 30 to 40 psi, impossibly hard and it will be the same as pumping up your 17 or 18 meter kite to 13.5 psi. Hoop stress is proportional to the pressure, 1/thickness amd the diameter.

By the way the ping test measures the hoop stress so it's actually going to inflate your kite to the correct pressure no matter what size it is. You should notice you have to pump a smaller kite to a higher psi to get it to ping.


I agree by the way, when a kite is due to explode it's gonna explode. Kites don't explode because they are pumped too hard, they explode because the stitching wore out and it was gonna blow anyway sooner or later.

I think those guidelines from naish should be followed of course, but if you are talking about how hard you can really pump up a smaller kite until it explodes, well ridiculously hard. For larger kites 17m or more, you probably don't want to get too much above 10psi.

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Re: I like my kite to be hard, when it will explode?

Postby TheRussian » Thu Aug 14, 2014 9:22 pm

I have only ever exploded one kite during pumping - I asked the rep how much pressure to put in & he said pump it up as hard as possible and it went bang ! I remember immediately beforehand the pump shaft felt very hard to push, but thought I could give it some more :roll:

I have been nervous about excessive pressure ever since, but some kites really need pressure - I found that an indicated 7 psi in a 13m Ozone Edge was not enough to take the creases out of the struts and on asking Ozone, they recommended 8 psi in all kites :o

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Re: I like my kite to be hard, when it will explode?

Postby plummet » Thu Aug 14, 2014 11:52 pm

edt wrote:
it's all about hoop pressure which depends on the diameter of the tube and the pressure, here's a helpful chart, assuming a new kite explodes with a rim stress of somewhere around 400 pascal of hoop stress these are all equivalent pressures:

6 inch diameter tube, 13.5 psi = 400 pascal
5 inch diameter tube, 16 psi = 400 pascal
4 inch diameter tube, 20 psi = 400 pascal
3 inch diameter tube, 27 psi = 400 pascal
2 inch diamter tube, 40 psi = 400 pascal


You can pump your 3m somewhere around 30 to 40 psi, impossibly hard and it will be the same as pumping up your 17 or 18 meter kite to 13.5 psi. Hoop stress is proportional to the pressure, 1/thickness amd the diameter.

By the way the ping test measures the hoop stress so it's actually going to inflate your kite to the correct pressure no matter what size it is. You should notice you have to pump a smaller kite to a higher psi to get it to ping.


I agree by the way, when a kite is due to explode it's gonna explode. Kites don't explode because they are pumped too hard, they explode because the stitching wore out and it was gonna blow anyway sooner or later.

I think those guidelines from naish should be followed of course, but if you are talking about how hard you can really pump up a smaller kite until it explodes, well ridiculously hard. For larger kites 17m or more, you probably don't want to get too much above 10psi.
EDT is bang on with his analysis.

A basic analogy is double the size half the pressure!. Ping test is best i think. I have to pump my 6m reo until the pump almost wont pump anymore.... but my 13 edge is at "ping" well before u hit the limit of my pump.

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Re: I like my kite to be hard, when it will explode?

Postby 14ToeSide » Fri Aug 15, 2014 3:44 am

Until you end the Pump handle on a Flat base Pump! Or it goes Kabooooom!!!!!

:pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump: :pump:

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Re: I like my kite to be hard, when it will explode?

Postby tautologies » Fri Aug 15, 2014 9:38 am

edt wrote: By the way the ping test measures the hoop stress so it's actually going to inflate your kite to the correct pressure no matter what size it is. You should notice you have to pump a smaller kite to a higher psi to get it to ping.
yes great elaboration.


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