This cool shot shows Marine Corps MV-22 Osprey generating Kopp-Etchell’s effect in the dust

25 November 2015

Image credit: U.S. Marine Corps. H/T @DCDude1776 for the heads-up

By David Cenciotti

A U.S. Marine Corps Osprey tilt-rotor aircraft is depicted with seemingly solid rotor disks.

The image in this post shows a U.S. Marine Corps MV-22 Osprey assigned to Special Purpose MAGTF – CR – CC during a TRAP (tactical recovery of aircraft and personnel) drill at an undisclosed location in Southwest Asia, on Nov. 16, 2015.

What makes the shot particularly interesting (and vaguely Star Wars-like…) is the halo effect caused by the sand hitting the blades and eroding their metal surface. The effect is more visible around the blades’ tips where the peripheral speed is higher.

Caused by the oxidation of eroded particles, the so-called “Kopp-Etchells effect” (named by war correspondent Michael Yon after Cpl. Benjamin Kopp, and Cpl. Joseph Etchells, two fallen American and British soldiers) makes the tilt-rotor aircraft more visible from distance, hence more vulnerable.

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