Helicopter Rotors on TV

[JohnR]

The other night I was amusing myself watching video's on You Tube and I came across one showing the very impressive convoy escorting the Queen from Frankfurt Airport, about thirty police outriders, loads of police cars and vans, Range Rovers carrying her Maj and an ambulance bringing up the rear. The video was presumably made by observers on a bridge over the autobahn with a mobile.

What I am intrigued by is there was a helicopter doing over watch, but the strange thing was the main and tail rotor were rotating at a very low speed. I know this is because of some optical reason something to do with how many images it takes a second; but what is it. I've noticed it before on other programs, such as the Air Ambulance.

As always, thanks in advance.

 

[Orionblamblam]

Shazam:

View: https://www.youtube.com/watch?v=AYQAKwCxScc

Over the years I've seen people claiming that these sort of videos are proof that the rotors on helicopters are purely cosmetic, because The Illuminatti are hiding from us the fact that these vehicles actually fly via antigravity or some such foolishness. Carry on the discussion long enough and eventually you'll drift around to the Flat Earth, and how jetliners are actually capable of flying tens of thousands of miles an hour and that's why passengers can fly from Australia to South America in reasonable timespans.

View: https://www.youtube.com/watch?v=jWIcVP6GRfw

View: https://www.youtube.com/watch?v=jQDjJRYmeWg

 

[JohnR]

Thank you for that very quick answer to my question, which has been well and truly answered. The second video really brought home the point with the main rotor stock still but the fenestrone still rotating but at a reduced rate. Thank you again.

 

[riggerrob]

Most helicopter rotors are constant-speed.

You often see this optical illusion with video of propellers rotating at differing speeds, especially when they test run engines on the ground.

If the video camera is recording at 60 frames per second, a rotor will appear not to turn at 60, 120, 180 or 240 rotations per minute. Any other recording speed will create the illusion that the rotor is accelerating or slowing down.