If there's only one post you'll read today, please have a look at the link inside this one

[vortexring 0]

http://www.michaelyon-online.com/the-kopp-etchells-effect.htm

Truly magnificent. For the pictures; for the words.

'for it's Tommy this, an' Tommy that, an' "chuck 'im out, the brute!" But it's "saviour of 'is country" when the guns begin to shoot.'

[shropshire 0]

Amazing

(.)Y(.)
Chivalry is not dead; it only sleeps for want of work to do. - Jerome K Jerome

[wmw999 2,545]

Thank you for posting that.

Wendy P.

There is nothing more dangerous than breaking a basic safety rule and getting away with it. It removes fear of the consequences and builds false confidence. (tbrown)

[quade 4]

It's static electricity. The effect has had a name for centuries, "Saint Elmo's Fire".

Yeah the photos are interesting, but I'm not really sure why it required being couched in this "good vs evil" mysterious language that implies "halos" from "angels". Here's a quote that's somewhat telling, " If not for such men, we would be at the mercy of every demon." Really? We're fighting "demons"?

quade -
The World's Most Boring Skydiver

[vortexring 0]

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It's static electricity. The effect has had a name for centuries, "Saint Elmo's Fire".

Thanks for the heads up. Despite having flown helicopters in such conditions, and in similiar conditions in 3 different continents of the earth. . .

And you're also wrong. The flashes of light are the sand particles emitting bright glows as they are disturbed. It is the piezoelectric effect, where a crystal makes a big energy shift when its crystal lattice is mechanically disturbed. This is the way a diamond record needle drives the sound into the amplifier. NVD's amplify about 40,000 times, so these very dim glows look like sparks. It isn't Saint Elmo's fire.

'for it's Tommy this, an' Tommy that, an' "chuck 'im out, the brute!" But it's "saviour of 'is country" when the guns begin to shoot.'

[quade 4]

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And you're also wrong. The flashes of light are the sand particles emitting bright glows as they are disturbed. It is the piezoelectric effect, where a crystal makes a big energy shift when its crystal lattice is mechanically disturbed. This is the way a diamond record needle drives the sound into the amplifier. NVD's amplify about 40,000 times, so these very dim glows look like sparks. It isn't Saint Elmo's fire.

Are you sure? If so, then what's the mechanic for them sometimes showing and other times not? Varying humidity would easily explain that for St. Elmo's Fire, but I'm not sure that works to explain varying triboluminescence.

quade -
The World's Most Boring Skydiver

[vortexring 0]

A further cause is simply just mechanical where you've minute particles - say concrete, hitting the blades leading edges when hover taxying inside ground effect. Less apparent on wet evenings though. Naturally enough this effect will be more obvious in sandy, gritty conditions that you'll find in the desert.

St Elmo's fire is rare. I've never experienced it, nor know of anyone personally who has. As for rotor-disc sparking? That's a very common occurance.

'for it's Tommy this, an' Tommy that, an' "chuck 'im out, the brute!" But it's "saviour of 'is country" when the guns begin to shoot.'

[LouDiamond 1]

I'm very familiar with that phenomenon and with the Helmand province. The HALO effect on the rotor blades is usually only seen in sandy LZ areas, at least in my experience.

"It's just skydiving..additional drama is not required"
Some people dream about flying, I live my dream
SKYMONKEY PUBLISHING

[vortexring 0]

Probably because there's more particles in the air, although I've seen it numerous times in temperate climates as well. Apparantly there's a bit of a debate into exactly what the cause is, but I reckon it's a combination of what I mentioned earlier. I guess I'll be paying it a bit more attention in the future.

What I did enjoy and find remarkable about the pics was the colour in such low light conditions. (Without everything being shades of green)

'for it's Tommy this, an' Tommy that, an' "chuck 'im out, the brute!" But it's "saviour of 'is country" when the guns begin to shoot.'

[rickjump1 0]

Thanks for sharing.

Do your part for global warming: ban beans and hold all popcorn farts.

[Gawain 0]

Good stuff. Thanks for the link. I didn't get to see anything like that in Iraq. Some of those shots are quite impressive in their quality.

So I try and I scream and I beg and I sigh
Just to prove I'm alive, and it's alright
'Cause tonight there's a way I'll make light of my treacherous life
Make light!

[rushmc 23]

Wow, and a great explination of WHAT we are seeing is great.

Thanks

"America will never be destroyed from the outside,
if we falter and lose our freedoms,
it will be because we destroyed ourselves."
Abraham Lincoln

[TankBuster 0]

Thanks. Great pictures. An even better narrative.

The forecast is mostly sunny with occasional beer.

[Lefty 0]

Haha, I saw the third picture and Iraq came rushing back. Saw that same thing through NODs, said "What the hell is that?" then went on about my business. Man, funny how most questions eventually get answered.

Edit: Can't believe I still had the video recording of it on an old thumb drive. Clicky.

Provoking a reaction isn't the same thing as saying something meaningful.
-Calvin

[ErricoMalatesta 0]

Its easier to look at than children in 15 different pieces from unmanned drones but then self serving propaganda usually is.

[JackC 0]

You know, if I were flying into a war zone, I really wouldn't want to be lit up like a christmas tree giving all the RPG weilding nutters out there something bright and shiney to aim for. It's not a halo, it's a bullseye.

[Skyrad 0]

I think the 'Hale Halo effect' would be a fitting name. Amazing pictures and a touching blog, thanks for posting.

When an author is too meticulous about his style, you may presume that his mind is frivolous and his content flimsy.
Lucius Annaeus Seneca

[warpedskydiver 0]

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A further cause is simply just mechanical where you've minute particles - say concrete, hitting the blades leading edges when hover taxying inside ground effect. Less apparent on wet evenings though. Naturally enough this effect will be more obvious in sandy, gritty conditions that you'll find in the desert.

St Elmo's fire is rare. I've never experienced it, nor know of anyone personally who has. As for rotor-disc sparking? That's a very common occurance.

I have never seen what is referred to St. Elmo's.

I only know of one person who has, when they were in a storm in the North Atlantic and there was a Sea King attempting to fast rope someone on board.

[warpedskydiver 0]

Yep if we only had pupils that size eh?

[warpedskydiver 0]

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Good stuff. Thanks for the link. I didn't get to see anything like that in Iraq. Some of those shots are quite impressive in their quality.

I bet the camera is a Leica.

[mnealtx 0]

>>Its easier to look at than children in 15 different pieces from unmanned drones indiscriminate bombings but then self serving propaganda usually is.<<

Fixed that for you.

Mike
I love you, Shannon and Jim.
POPS 9708 , SCR 14706

[mnealtx 0]

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Quote

Good stuff. Thanks for the link. I didn't get to see anything like that in Iraq. Some of those shots are quite impressive in their quality.

I bet the camera is a Leica.

Actually, I believe it's a Nikon D70.

Mike
I love you, Shannon and Jim.
POPS 9708 , SCR 14706

[vortexring 0]

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Its easier to look at than children in 15 different pieces from unmanned drones but then self serving propaganda usually is.

Yes, yes, errico; now run along.

'for it's Tommy this, an' Tommy that, an' "chuck 'im out, the brute!" But it's "saviour of 'is country" when the guns begin to shoot.'

[Gawain 0]

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You know, if I were flying into a war zone, I really wouldn't want to be lit up like a christmas tree giving all the RPG weilding nutters out there something bright and shiney to aim for. It's not a halo, it's a bullseye.

Part of that is the enhanced low-light sensitivity of the camera. Not having seen it first hand myself, I can only speculate, but I don't think this is highly visible to naked eye, requiring NODs or other night-vision aids...others will correct me.

So I try and I scream and I beg and I sigh
Just to prove I'm alive, and it's alright
'Cause tonight there's a way I'll make light of my treacherous life
Make light!

[vortexring 0]

No, you're right Max.
Jack, it can sometimes be visible to the naked eye, but if you're close enough to see it, you're also close enough to see the light emitting from the a/c's internal instruments! Coupled with the noise...

A similiar effect can be seen if you go into your garage with a sugar cube and a hammer. Ensuring it's properly dark, and your eyes have adjusted (and you can remember where you've placed the sugar cube), smash it hard with the hammer and see what happens. Now, imagine wearing an image intensifier and consider how much brighter the effect would be.
Then explain to the missus what on earth you're up to. . .

It's a real shame a picture of the light levels as seen from the human eye wasn't taken - I reckon people might then appreciate the pics better.

'for it's Tommy this, an' Tommy that, an' "chuck 'im out, the brute!" But it's "saviour of 'is country" when the guns begin to shoot.'