01 September 2009

The Kopp-Etchells effect




When helicopters pass through dust storms, contact of the particles with the rotating blades produces either sparks or static electricity. The phenomenon has been observed during combat operations in Afghanistan; Michael Yon has documented the effect, and has named it after two soldiers who died there.

Credit, with more photos and information. Via Izismile.

12 comments:

  1. I know when I was in the Army at Ft. Campbell KY in the early 90's at night you could see a blue glow from the static electricity as the blades moved through the air. Very faint and definitively not white. I could believe it is sparks from the sand impacting the rotors.

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  2. I know when I was in the Army at Ft. Campbell KY in the early 90's at night you could see a blue glow from the static electricity as the blades moved through the air. Very faint and definitively not white. I could believe it is sparks from the sand impacting the rotors.

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  3. Definitely video material!

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  4. I'm not sure if what's happening in the pictures is the same thing, but something similar is definitely visible at night... and is VERY visible at night using NVGs. (Former CH-47 crewcheif)

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  5. I personally witnessed this effect during an exercise in the Mojave desert at the National Training Center at Ft. Irwin California. Only difference was the helicopter - the one I saw was a Blackhawk. Cheers

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  6. The Kopp-Etchells effect was named by Michael Yon after two soldiers, however only Etchells was from the U.K.
    Kopp was a U.S. soldier.

    7/18/09
    Kopp, Benjamin S.
    Corporal 21 US

    7/19/09
    Etchells, Joseph
    Corporal 22 UK

    The electro-luminescence so beautifully captured by Michael Yon is a phenomenon I'm sure most helicopter pilots and crews are familiar with. It might be akin to St. Elmo's Fire. I have asked my son, who is a CH-47F Chinook pilot in Afghanistan, if they have a name for it. When I get his answer I'll post it. In the meantime, I like the naming of it after two valiant soldiers.

    Rest In Peace, Honored Valiant Men. As a Blue Star Army Mom, I am proud to know my son served with you as a Brother in Arms.

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  7. Electrical effects exist, for sure, but I don't think this yellowish flare effect is such. They use titanium as an abrasion cover for the rotor blades, and this looks very like what happens when you put a titanium sheet into a grinder -- which dusty air might resemble. Small particles of titanium knocked off ignite in air.

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  8. I suspect that it is the titanium sparking off the dust, but not a spark of electricity, more like the spark of a flint on a Zippo.

    My titanium golf clubs do the same thing on dirt (an experience not available to the proficient golfer, who is familiar only with the verdant, manicured carpet of the fairway) and it's especially noticeable in low light.

    As is often the case with neat sh!t, the spark does absolutely nothing discernable to improve accuracy.

    Titanium is a pretty tough metal, but I cannot help but wonder what kind of replacement rate those rotors have in such an abrasive invironment.

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  9. Apache refueling in dusty Arizona conditions makes a beautiful blue dust spark halo

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  10. Hello,
    I came across this site while researching for my masters thesis. I beleieve that we have found the cause, and a possible solution to this phenomenon. Feel free to contact me for more info at: jerandsta@gmail.com thanks again.

    LT Jeremy Young

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  11. Sorry that email is

    jerandstac@gmail.com

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