A collection of sublime images from embedded journalist Michael Yon of what happens when helicopters fly through dust storms. Lightning bolts arcing around the blades are thought to be created by static electricity arising from friction between two dissimilar materials - in this case the metal blades and the sand. Yon coined the term "Kopp-Etchells Effect", named for two soldiers killed in Afghanistan.
Full set of images here. I suspect the blurring is due to the long exposures necessary to capture the effect.
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Stunning pictures, although I would have thought the sparks were caused by the dust erroding the titanium coatings on the blades away - a bit like an inverted grinding wheel.
I believe the effect you describe can also occur in flight, in certain types of cloud or just via air resistance alone; but not specific to just dusty conditions.
I could be wrong though...any other thoughts?
Not ligntning bolts, just sparks from individual dust particles striking the blades accumulated due to teh exposure. Nice thought naming it after two soldiers but it's already a known effect.
We see this effect in sandblasting, its the sand hitting another surface (in this case the blades) at supersonic speeds. The sparks are from the sand granules splitting, and not due to abrasion of the rotors themselves.
discharge of static electricity...that's all it is. Happens all the time, much more intense with NVGs.
Must be static. Titanium doesn't spark as far as I know.
ladies and gentlemen - do you think maybe it could be the sand and debris in the air around the blades? think on it.
In regard to Ben's previous post: Titanium sparks with nice long, white streaks. Steel sparks with shorter orange ones. It's one way to test for real titanium.
I like how everybody on the internet knows fucking everything and nobody is ever wrong. cool pics, nice effect, leave it at that.
yes adam, lets never question anything. ignorance is bliss.
"I suspect the blurring is due to the long exposures necessary to capture the effect."
A helicopter hovering in a dust storm like that would be blurred much more if this was a longer-exposure. Its a relatively normal exposure... Its blurry, because its a moving object, in a DUST STORM.
Dust catcher systems or not, can you imagine what the 1st stage compressor blades look like?
or id could be some runway lights..... look at the spacing of the lights. they're too evenly spaced for it to be static or lightning or anything like that. There's just too much consistency
Clearly photoshopped!
I think Jesus did it. >.>
Hitler invented the Helicopter
Does no one remember the scene from "The Hunt for Red October", when the character Jack Ryan is trying to get aboard the American sub USS Dallas, and they have a guy with a pole to ground the line before they try to grab him? Ryan's leg contacts the guy and sends him over the side of the sail (he's in a safety rig and so suffers little more than a nasty electric shock, though they did add some blood for effect). Just static electricity. Happens a lot with helicopters.
My lord, get this man an anti-static anklet. HURRY!
http://img692.imageshack.us/img692/7579/7576104md.jpg
(Image is of a man using a GRINDING WHEEL)
(The grinding wheel is ROTATING, giving off non-electrical sparks as friction-heated metal is flung away from the metal and wheel)
"Kopp-Etchells Effect" must be a replacement phrase for "I was too moronic to be trusted around fast moving machinery in Shop Class, so I make up new imaginary science terms to further shame myself and my parents".
It could be a piezio-electric discharge effect generated by the blades striking alumina particles in the sand. Does the effect happen in humid as well as dry climates?
Though there may be some mechanical effect generated here as proposed by many above, anyone who has the opportunity to see these aircraft on clear sand-free nights would be able to note the static discharges at that time. To prove it is static electricity and not a mechanical effect, touch one of these aircraft before it is grounded (electrically) to see what happens.
Oh, and two dissimilar materials will only cause a static effect if they are both dialectric (insulating) materials. This won't happen between metal and sand (unless the metal is painted -- but that's not what the article implies).
Almost all of you people are a bunch of assholes. the author is accurate in his explanation of why said effect is caused. I don't give a crap about educating you as to why, the author put it perfectly. (BTW - gifted in science since elementary school, no expert, just educated).
Some of the negative or argumentative comments are from people basing it on your "similar" experiences that are of no similarity at all because it was caused by using entirely different materials at a highly different speed, in an extremely different environments. A circular saw blade (or w/e commenter was working with) is not of the shape or design to rotate the air around it, as the 'chopper blades do...nor was there the same HIGH density of airborne sand. Blades designed to move air at extremely high velocity + atmosphere packed with airborne sand = not the same shit at all that was described in comments above.
Your cars breaks = ceramic/Kevlar, what-ever... grinding down at high speeds against the metal rotors. Sparks? Anything visible? Ok...
And the jackass who got their stained panties in a knot regarding the "long-exposure" photo, get a fucking life. you prob care more about minor technicalities (that may or may not be true)than you do the neglected kid(s) you probably have. Go spend some time with your wife, "Doug", so she'll stop calling me for some real dick all the time.
Fuck you those who disagree. I worked this week, got paid excellently, and am stumbling the web. I am totally chilling and never normally waste a minute of fucking time replying to shit like this. But some of the previous comments are just moronic. My responsibilities are handled, I'm smoking some great weed and chilllllllin online. What's your fuck-ass excuse?
Kudos to the author on a very cool article.
@ wtf (poster No. 21)
Agreed.
Check out St elmo's Fire
wtf, please let me know next time you're in town. We need to party.
BTW, Mr. Yon was mistaken. Those photographs were taken on Veteran's day, those are sparklers coming from the blades in celebration. Where do you think all your tax dollars go?
This is clearly evidence of the existence of the Flying Spaghetti Monster. All Hail FSM! May the Pesto be upon him!!!!!!!!
And speaking of the death panel conspiracy theory, has anyone been checking out Arthur Goldwag's coverage of Sarah Palin's conspiratorial beliefs? How sad is it that we still have candidates for national office that believe things that fail the snopes.com test.
A controversial teaching program linked to an alleged cult leader managed to slip into 44 New York City public schools because it didn't cost enough to trigger detailed background checks, school officials said yesterday.
For wtf, post 21. if you are so well educated, you need to learn how to spell "brakes"
#12 lol John, you realize we're talking about the lighting effect above the helicopter and not the green lights on the ground right? Those are indeed runway lights. lol Too funny
Its just the blades grinding against the sand. Sandstorms can move as fast as cars if not faster and the blades are moving incredibly fast aswell. Strike a rock hard enough on metal and it generates a spark. Sand is a mixture of salt and rocks (usually just incredibly small rocks).
Its just amplifying the effects because of how much sand there is.
No you cant take a single grain of sand and make a spark (well in a high tech lab with a special launcher or something maybe) so dony try it and deny it -.-
It could be static electricity but its unlikely, static electricity is caused by two dissimiliar materials rubbing up against eachother, at these speeds it would be striking not rubbing.
As a guy who's spent some time with the aircraft in the photos ...it's static electricity ...when you hook up to move equipment or what have you you must use a grounding hook first ..it downtown matter what the weather dust sand or what not ..failing to do so will give you a shock that will knock you off your feet ...I've seen the rotor glow in all kinds of conditions.
I'm quite familiar with these photos and many others by Michael Yon, they are very authentic. Taken in 2009 he referred to this corona effect as "Kopp-Etchells effect", to honor Cpl. Benjamin Kopp, and Cpl. Joseph Etchells, recently fallen American and British soldiers. I work with Michael Yon as his photo editor so yes it was put through photoshop but only for color & contrast. He is well known for his original photos, no special effects, they have to be kept as authentic as possible. The green light are landing lights, the sparks flying off the blades is a real effect not "photoshopped". It's simply a static electrical discharge. And Doug was right, trying to focus a camera at night( the only lights were from the helicopter & landing lights) while being blasted with sand and wind from the blades makes it a bit more difficult to focus.