The Kopp-Etchells Effect (2012)

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25 points·eproxus··6 comments

The Kopp-Etchells effect was first documented during combat operations in Afghanistan. The photographer Michael Yon named the effect after two soldiers who died there, Koop, a US Ranger, and Etchells, a British soldier. Both were killed in combat in this province of Afghanistan.

Props to the photographer for naming the effect after the soldiers who lost their lives.

Pity the article has been getting Kopp's name wrong without correction for the last 10 years though, despite containing several other changes suggested by the photographer.

The spontaneous combustion part here feels bit weird; I imagine the phenomenon is more like when you hit metal with angle grinder and sparks fly out, where the abrasive action heats the particles up to ignition point. At least I wouldn't call that very spontaneous.

The author's claim is that the powdered metal oxidizes, not directly abraded.

https://en.m.wikipedia.org/wiki/Pyrophoricity

My first guess was triboluminescence, but yeah, pyrophoricity sounds very plausible as well.

The movie scene writes itself:

(the scene: a firebase in Afghanistan. A platoon of weary grunts are landing in a chopper, returning from a tough mission)

Marine A: Did you guys notice that halo around the rotors when the chopper took off, after we landed at the site?

B: No, douchebag, we were checking our weapons again.

A: That's called the Kopp-Etchells effect.

B: You're going to explain it to us, aren't you?

A: You see, the leading edge of the blades has titanium on it, so ...

B: (chopper lands) Well, here we are! Looking forward to hearing all about this, next mission, douchebag.

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