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Old 07-27-2005, 03:23 AM
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Default ELECTRIC KITE EXPERIENCE

You are flying along and suddenly you feel something painful jolt up your arm. The shock may be intermittent or continuous, annoying or downright painful, you may just hear a discharge whenever you jump and so on. One of the most common causes apparently is IMMINENT lightning, very close to where you are waving around a potential 100 ft. lightning rod on a flat surface. Doesn’t sound real good does it?!

During the recent Velocity Games in Texas, Mother Nature catered a nearby storm that lit up one of the heats. Shannon Best described it as a painful sensation as he flew his kite but he was not going to be the first off the water. It was getting pretty intense however. Once another guy bailed Shannon landed pronto. A nice squall cloud moved through shortly thereafter.

The causes of these static electric discharges could include many factors such as the naturally occurring voltage gradient from the ground up to the sky to something called the Electret Effect that involves semiconductor properties of kite line. Worrying about insulative value of bindings, bars, gloves, booties is generally a waste of time and may have minimal useful effect. Immanent lightning can do wonders for the voltage gradient and give you that special sense of urgency IF you react well and early enough.

Avoiding lightning – Checkout the forecasts, always be aware of the weather around you and moving in, KNOW weather patterns for your riding area. Lightening can strike more than 10 miles from a storm cloud and can develop temperatures of 50,000 F (much hotter than the surface of the sun!), 100,000,000 volts and 30,000 amps. IF you see lightning and hear thunder within 30 seconds you need to land and secure your kite pronto and move to safe shelter. Wait 30 minutes after all lightning, thunder activity has stopped (the 30/30 Rule). The 30/30 Rule triggers when the lightning is within 6 miles. Strikes out to 10 miles have been documented so don’t screw around. Pain in the butt? Maybe but almost 70 people are struck each year in the USA. Why join up?! A large part about kiteboarding safety is developing hazard awareness and avoidance. Here's a heads up, the rest is up to you.

More about static electricity, lightning and kiteboarding at:
http://fksa.org/viewforum.php?f=94
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Old 10-20-2005, 05:33 AM
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More related info here: http://www.kiteforum.com/phpbb/viewtopic.php?t=2321146

including:

'Though if you're sailing and not touching ground you shouldn't be able to have any concequences from it if it strikes you. !'

Wrong. How many people do you know of that have been struck by lightning, particulary while standing in a ground (water) that suffer no injury (burns from a 50,000 F arc)?

You caught the fact this guy lives in Florida, right? We have had a lot of people injured and some killed by lightning, more than any other place in the USA.

Have you ever seen lightning strike water? It happens very often and it strikes the highest object in the area most frequently. The surface of the sea IS THE GROUND! Forget about the kite for a moment. Just consider all 5 to 6 feet of you on an open sea. You're the highest object in the area.

For more info, checkout The vast majority of lightning injuries and deaths on boats occur on small boats with NO cabin. Sounds like us.

More stats, • The odds of becoming a lightning victim in the U.S. in any one year is 1 in 700,000. The odds of being struck in your lifetime is 1 in 3,000. * Your odds in ignoring an OBVIOUS hazard are much greater of course and even more so in Florida.
* From: HERE

Being a survivor of a lightning strike may not be a picnic either. Lots more people survive than die in lightning strikes, sometimes with serious impairments. More about this HERE and HERE.


The following figure about lightning and boating is from:
http://www.cdc.gov/nasd/docs/d000001...07/d000007.pdf
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Old 10-20-2005, 07:42 AM
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Any RF, electrical engineers/technicians, physicists, informed individuals, etc. with insight on these and other influences (including atmospherics) on static electric discharges from kite lines? Also of interest are semiconductor properties of Dyneema/Spectra (HDPE) line/related effects and altered conducting properties induced by saline moisture and charged atmospheric aerosols.

It seemed like a simple question, "what causes electrostatic kite line discharges?" The potential answer(s) seem to be growing more complex rapidly.

Thanks!


More on the technical side of static discharges from kite gear appears at:
http://www.kiteforum.com/phpbb/viewtopic.php?t=2318240


Wow, thanks for all the input. In my experience these electrostatic kiting discharges have been mildly to fairly painful, noisy on occassion and by one telling, even visible as an arch that followed a jumper. I have some concerns that some sources of electrostatic discharge include some that may closely preceed lightning.

Some of the things that have come up so far in trying to explain causes for electrostatic kite line discharges follow.

Voltage gradient -

Manfred summed it up well as:

"1.: in weather near to a lightning, even if there actually is no lightning,
there can occure potentials of more than 10.000V/m (vs sunshine 100-300v/m). If you jump up then, you (your kite and yourself) can easily load up to 150.000V - when you touch ground there may be a small lighning. "

This has been an issue with balloons with conductive tethers, kite lifting antennas and has resulted in a lot of damaged equipment. Regarding injuries?


Dyneema and Spectra are made of HDPE, a poor conductor or semiconductor in dry conditions. Still, if I have it right, these materials can develop significant charges through the Electret Effect.

****ney Lad provided input in this direction with:

"Dry kite line might be an insulator but it can still be used to generate / hold a charge. Pulling an insulator through a charged environment such as dry kite lines in a charged airflow sounds a lot like a van de graff generator to me.

ZAP! don't do it...."

I understand that this is the case with Cable Generators that utilize the Electret effect that are similar to Van De Graff generators.


Chis Glazier indicated:

"First of all understand that spectra or dyneema kitelines are excellent insulators and do not conduct electricity. Otherwise every power line incident involving a kiteboarder would certainly result in a dead kiteboarder. However if kite lines are wet with salt water, they may may not be good insulators. Interestingly, fresh water is quite a good insulator and does not conduct electricty very well. "

The poor conductor part is true but then there may be the Electret effect at work as well. In the past the coating of the exterior of the line with saline water was the only way I could explain electrostatic discharges. I didn't think about the possible contribution of aerosols discussed below.


Aerosols can also contribute to charge development:

"Still another source of atmospheric charge collected by the cable generator are Aerosol Charges. These are particles of dust or water which form dipoles and disproportionately collect one charge or the other. Where ions carry only single or double units of charge, Aerosols carry 100's to 10's of thousands of units of charge. The fact humidity is such an important factor in the output of the cable generator indicates that aerosols are an important source of the energy it collects.."
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Old 07-23-2007, 08:13 AM
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More about boating and lightning at:
http://www.cdc.gov/nasd/docs/d000001...7/d000007.html

More about diving and lightning at:
http://scuba-doc.com/lightdive.htm
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Old 10-12-2010, 10:53 AM
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VIDEO - Kiteboarder Struck by Lightning



Marc
Cabrinha '09 16m XBOW / GK '08 12m & 9m Trix / Eclipse '08 14m Thruster
Kiteboarding Videos: Feat. GK, Litewave, Flyboards, Ozone, Naish, & More
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Old 10-08-2012, 09:10 AM
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The following is from:

"Kiteboarder Struck By Lightning"
http://fksa.org/showthread.php?p=50249#post50249

We experience some electrical phenomena while kitesurfing, just not apparently all such phenomena like inducing lightning strikes, to date anyway. Why is this?

Spectra and Dyneema kite lines are poor electrical conductors comprised of Ultra-high-molecular-weight polyethylene. If they are coated with salt and moisture the conductance may improve somewhat but how much? Looking at the example of most incidents involving one of our kites hitting high tension power lines, the lines conduct so poorly that they melt (and often the kite catches on fire). In some cases the kiter may suffer some flash burns but isn't electrocuted which you would expect with a reasonable conductor. I have read of kite related electrocutions when different line material was used say like nylon fishing line. Note to self, don't use nylon fishing line to fly kites! Folks have fired rockets into storm clouds trailing a copper filament and have nicely induced a linear bolt of lightning down the filament to the ground.

We know that kites and lines can have static discharges. These seem to occur both in conditions of immanent lightning strikes and in other potentially less threatening conditions. The static discharges appear to be caused by the Electret Effect and the line moving through aerosols.

A good question is, can our kite and line setups in kitesurfing attract stepped leaders from clouds and in turn lightning strikes? Falk apparently at less than seven feet in height did this on an open beach but I understand people are better conductors than kitesurfing system materials and a person's head may be pointier than a blunt, poorly conducting kite. The apparent lack of such an event seems to support the low probably of such a thing happening and yet there are the static discharges described above. It is important to note that untold numbers of people have been struck on level surface through time, no tall conductor necessary much less a kite. As such I would think a planning kiter might be struck regardless of having a kite up or not by virtue of having an induced positive charge and being the highest, pointy object in the vicinity. Thoughts?



Some background on induced charges and lightning.
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Last edited by RickI; 10-08-2012 at 09:37 AM.
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