is it real or a model?

[t68]

Found this on you tube, there must be a simple explanation.
[nomedia="http://www.youtube.com/watch?v=_Isi2cwJsp4&NR=1"]YouTube - HOW the f#*@ is this helicopter flying?[/nomedia]

Can’t be real can it?

 

[Bonza]

There's a version of it on youtube somewhere with an accompanying explanation - from what I remember it has to do with matching the camera's frame rate to the rotation of the helicopter blades so it doesn't appears as though they're rotating, so from what I understand it's real, just the film is manipulated. At least I think that's what the explanation was - apologies if I'm mistaken. Have a look around youtube and you might be able to find it.

 

[harms]

Bonza is right, here are some other videos of the same effect...
[nomedia="http://www.youtube.com/watch?v=oBxz1k_apnI&feature=related"]YouTube - Helicopter flying without propeller[/nomedia]
[nomedia="http://www.youtube.com/watch?v=mfXApFfMKuo&feature=related"]YouTube - levitating helicopter[/nomedia]
[nomedia="http://www.youtube.com/watch?v=xx1YwT9q8IQ&NR=1"]YouTube - Cool Chinook Video.[/nomedia]
[nomedia="http://www.youtube.com/watch?v=4EvUwPRsnEs&feature=related"]YouTube - Optical effects of a moving propeller shot on video.[/nomedia]

...and some other strange ilusions
[nomedia="http://www.youtube.com/watch?v=pVcuntWruuY&feature=related"]YouTube - A strange effect[/nomedia]
[nomedia="http://www.youtube.com/watch?v=mwJWi2mhXR0&feature=related"]YouTube - Illusion of Antonov-24 propeller "deformation" in flight[/nomedia]