A friend of mine is a pilot (he flies a King Air 350). A few days ago he took this photo which I thought was pretty cool. I asked if I could post it here and he said yes. So here it is!
Reminds me of the Russian anti-gravity helicopter.
What is it we are seeing here?
Were there multiple exposures?
Rolling shutter. It’s a digital camera thing.
See also: propeller shedding boomerangs.
Right; it’s a single exposure (i.e. he only pressed the shutter release button once) but due to the high RPMs of the propeller and the way a shutter works in most digital cameras, an interesting effect is produced that shows different parts of the blades at different points in their rotation.