“Shock collar” generated by U.S. Navy EA-18G Growler caught on camera.
Last month we published an amazing shot showing a U.S. Navy EA-18G Growler Electronic Attack aircraft with the Electronic Attack Squadron 130 (VAQ-130) “Zappers”, based at Naval Air Station Whidbey Island, Washington, flying at low level on VR1355, one of the low level routes running through national parks in the Cascade Mountains, Washington State, in the U.S. Pacific Northwest region.
The visible shock waves along the wings trailing edge axis made that photo, taken by photographer Dave Honan with a Canon 1DX MkII with 100-400L MkII lens and 1.4x MkIII extender in October 2020, particularly interesting.
However, that shot was not the only dramatic photograph taken by Honan on that day. The one that you can find in this article was taken five frames after the shockwave photo: considered the camera shoots at 14 fps, this new image represents the same aircraft 5/14th of a second after the first shot.
As you can see, a “shock collar“, also known as “vapour cone” has formed around the Growler less than half a second after the previous one.
“The cone itself was fully developed for only three frames — it appeared and vanished in that almost imperceptibly brief span of time,” Dave told us in an email.
The shock collars are generated by a sudden drop in pressure associated with high speed that allows water vapour to condense as vapour.
Although many believe that these clouds appear when a jet “breaks” the sound barrier, they can appear when the aircraft flies at subsonic speed, in humid air, as in the photo taken by Honan.