File:Gliding-Swifts-Attain-Laminar-Flow-over-Rough-Wings-pone.0099901.s004.ogv

English: Laminar-turbulent transition at maximum lift. Video demonstration of the detection of laminar-turbulent transition with the stethoscope on a fully extended swift wing at 10 ms−1 attaining maximum lift coefficient. At maximum lift the wing was partly stalled, resulting in light vibration, which complicated the use of the stethoscope. If the wing hits the stethoscope it can move a feather, which requires care during actual measurements. The original position of the feather was typically recovered by resetting the angle of attack and speed to zero and, if needed, careful preening of the feathers, and starting over.