What's Wrong with this Picture?
What’s wrong with this picture?
The picture is upside down. It was taken when the helicopter was near the apex of a loop. You can tell not only by the sun reflection on the bottom, but also by the angle of the rotor blades.
When helicopter is flying normally, rotor blades form a shallow cone. If you were to draw a straight line from the tip of one blade to the tip of the opposite blade, this line would pass above the rotor hub:
Rotor blades are flexible and support the weight of the helicopter only because the centrifugal force is pulling them apart. You can think of the helicopter as hanging on the clothesline. No matter how tight the clothesline is, it’s never going to be completely straight.
The second hint is that the blades in the picure are feathered (their pitch is close to zero). The rotor is not generating any lift, as if the helicopter is on the ground:
Normally it looks like this: