Illusion of flying helicopters with stationary propellers

The phenomenon of hovering helicopters above the takeoff yard, flying higher and higher while the propeller almost stood still completely stemming from the shooting speed and the number of frames per second.

The video shared by Chris Chris's account on March 3 shows that the helicopter seems to be magically hovering in the air, according to Popular Mechanics. In the video, the propeller moves slightly at some point but does not rotate continuously as usual when the helicopter takes off. Even when flying forward, the propeller still looks motionless and only starts spinning right before the video ends.

The helicopter seemed to be magically hovering in the air.

According to Chris Chris, the helicopter's confusing motion is due to a trick on the camera when the shutter speed of the machine matches the speed of rotating the rotor fan.

Shooting speed is the time the camera takes to capture light for each shot. The more the camera takes more time to light up, the more blur the frame will effect when moving in clarity in the picture. Fast shutter speeds can create strange frames, even making each rotor invisible.

The number of frames per second also contributes to this phenomenon. "Imagine you shoot a video of 24 frames per second of a helicopter rotor spinning a full circle every second. In the video, every spin that follows will be divided into 24 frames. You will see the rotor blades spinning as usual. But if the rotor rotates at the correct speed 24 times a second, you still turn in 24 frames per second, each rotation will be shown in one frame.The rotor will return to the original position each time. The camera captures a frame, so they look like they're standing still, ' Chris Chris explained.

The number of frames per second can also make the rotor fan look like it is turning around or even bending in an S shape.