Clever people, these Russians...

[PTT]

http://emuse.ebaumsworld.com/video/watch/21751/

:confused:

:ok:

[Razor61]

What kind of video camera would be operating at speed (frames per second) like that?

[scopey]

Selected frames removed? The FPS seems to vary throughout...

[Green Flash]

Tornado-cam. I think it uses a CCD. Check out the high res slomo on the BBC sports (F1, etc). T-cam can go to something like 2000fps, not bad for video. It works in conjunction with Hawkeye. Takes some memory, mind.

[Genghis Couldn't]

Well, for all the doubters, that is the proof that helicopters fly simply because they are so ugly that the ground repels them........

[Pilot Pacifier]

That's the Czech Republic Hind that was at the Belgian Helidays meet last weekend in Liege, I think!

Did view it through a beer goggle haze though! :8

[PPRuNeUser0211]

Razor, the camera doesnt have to run at the same fps as the rpm of the rotors, the rpm just has to be a multiple of it (eg 30 fps but an rpm of 300 means that the rotors appear in the same position on every frame but have in fact rotated ten times between the frames)

Hilarious to read some of the posts below that video though!!!

[Razor61]

Thanks for clearing that up.
It annoys me when people's first reaction to a lot of aviation videos is "That's Fake".
I feel like replying to them personally but can't be a%sed.

[ChristiaanJ]

Razor61,
It's a bit like using a strobe flash to "stop" motion, e.g., a running engine.

With video it's only coincidence when there is a such a near-perfect match between rotation and frames-per-second.

But I do remember a BBMF Lancaster "four-engine-out" flypast with the props seemingly windmilling very slowly.... :)

With todays very high shutter speeds, it can become a nuisance on aircraft photos as well, when the props are perfectly "frozen".

[green granite]

Razor, the camera doesnt have to run at the same fps as the rpm of the rotors, the rpm just has to be a multiple of it (eg 30 fps but an rpm of 300 means that the rotors appear in the same position on every frame but have in fact rotated ten times between the frames)

That's all very well, but it would mean that the rotor speed remained constant through out the entire display, is that likely?

[oli,_the_original]

If you watch carefully, the rotor steadily moves back and forwards a few degrees throughout the display, so the rotor speed is probably varying, although, as said, it depends on multiples of frame speed, so if, for example, 25 frames per second, and it increases by 100 RPM, then slight rotor movement during transition to new RPM

[ChristiaanJ]

That's all very well, but it would mean that the rotor speed remained constant through out the entire display, is that likely?It's very likely, becoz them whirry things fly with essentially constant rotor rpm.
It's indeed the blade pitch that is varied "cyclically" for pitch and roll control and "collectively" to go "up and down", not rotor rpm.

[MightyGem]

Another one here. (http://www.youtube.com/watch?v=DFCsFTnW5y4)

[ChristiaanJ]

MightyGem,
That's a PERFECT one.....

It makes one suspect that rotor rpm can be set to some pretty exact round figure (say 300 or 350 rpm) which then exactly matches the 25/50 fps rate of the camera.

[Brian Abraham]

The effect can be seen when night flying on some types. The strobes can make the rotor appear that it has stopped. :eek: