As I said “The threads flutter and swing back and forth in the air stream and the camera freezes them in whatever position they are in when the exposure is taken. From what I saw first hand, the center of the thread flutter and swinging was straight back from the tape holding the thread at all test points.” The ends of the threads moved about 1/4” to 1/2” in either direction from center, but the center of the flutter on all test points was directly behind and down stream from the attachment points. I was unable to detect any spiral air flow at any of the test points. The engine on the Kaos has “0” right “0” down thrust.

If there is spiral air flow it is very weak and invisible to the test threads I used.