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View Full Version : Gravity defying helicopter



nsteense
06-01-2007, 06:26 AM
Nothing special except...
http://www.youtube.com/watch?v=DjPfzKbYDXw&eurl=

MEGILE
06-01-2007, 06:34 AM
Ahh the wonderful world of camera speed

Divine-Wind
06-01-2007, 09:29 AM
Sounds like raaaid physics to me. http://forums.ubi.com/images/smilies/shady.gif

raaaid
06-01-2007, 11:58 AM
the interesting thing about stroboscopic effect is happening with the naked eye which contradicts current theory on persistence of vision

BSS_AIJO
06-01-2007, 03:58 PM
Originally posted by raaaid:
the interesting thing about stroboscopic effect is happening with the naked eye which contradicts current theory on persistence of vision


hmm, I think persistance of vision is a urban ledgend.. Heck if it actually was we woulnt even know there is a stroboscopic effect.. 8^P

Actually for an interesting experiment with it, go find an old IBM green screen monitor displaying something... Watch it and chew an ice cube at the same time. You will get a real first had understanding just how easly our vision is messed with.

At the same time, our vision is probably persistant. That would be the vision part. The brain is where it all fails, as that has to chop the stream into indvidual frames and do the very fast parallel object recognition on everything. Heck most magic trics are designed to expoit the way our brain process the stream, as it seems to be useing look ahead and look behind all while keeping up firmly in the present.. Still, when it sees an upcomming shortcut it will take it.

With occasional humerous results.


BSS_AIJO

Zeus-cat
06-01-2007, 04:04 PM
Notice that the main rotor blades are bent upwards indicating they are taking a load (helicopter blades like these droop when the helicopter is on the ground). The camera frame rate is nearly perfectly synched with the rotation of the blades.

Lurch1962
06-01-2007, 04:19 PM
Moreover, the shutter speed is VERY fast--Not only is the main rotor perfectly frozen in each frame, the faster-turning tail rotor is sharply imaged, too.

major_setback
06-01-2007, 04:48 PM
Originally posted by Lurch1962:
Moreover, the shutter speed is VERY fast--Not only is the main rotor perfectly frozen in each frame, the faster-turning tail rotor is sharply imaged, too.

I don't think it necessarily has to be so fast, as long as it's a figure that is a fraction of the rotors' , ie. if the rotor has 3000 rpm then the shutter could capture every 10th rotation in the same exact space.(or for that matter every 11th rotation, or ever 149th rotation.)

Badsight-
06-01-2007, 05:09 PM
cool subject

the brain processes sound & sight at different speeds (sound is processed faster)

the brain then does real time "editing tricks" to mix what you see & hear so they happen together

how it does this still isnt knowen

Hanglands
06-01-2007, 05:12 PM
Ditto for major_setbacks comment.

But if this vid was edited to include some sort of industrail sounding 'whine' effect rather than the archetypal 'duh duh duh wop wop wop' rotor blade sound, it would be pretty funny.

Zeus-cat
06-01-2007, 05:40 PM
I don't think it necessarily has to be so fast, as long as it's a figure that is a fraction of the rotors' , ie. if the rotor has 3000 rpm then the shutter could capture every 10th rotation in the same exact space.(or for that matter every 11th rotation, or ever 149th rotation.)

You are confusing shutter speed, the length of time the camera lens is opened to emit light, and the frame rate which is the number of pictures taken each second. Lurch1962 is correct, the shutter speed is indeed quite fast as the rotors are not blurry. If the shutter speed were slow the rotors would be blurred.

EiZ0N
06-01-2007, 05:55 PM
Originally posted by Zeus-cat:
<BLOCKQUOTE class="ip-ubbcode-quote"><div class="ip-ubbcode-quote-title">quote:</div><div class="ip-ubbcode-quote-content">I don't think it necessarily has to be so fast, as long as it's a figure that is a fraction of the rotors' , ie. if the rotor has 3000 rpm then the shutter could capture every 10th rotation in the same exact space.(or for that matter every 11th rotation, or ever 149th rotation.)

You are confusing shutter speed, the length of time the camera lens is opened to emit light, and the frame rate which is the number of pictures taken each second. Lurch1962 is correct, the shutter speed is indeed quite fast as the rotors are not blurry. If the shutter speed were slow the rotors would be blurred. </div></BLOCKQUOTE>
+1

FritzGryphon
06-01-2007, 06:01 PM
I never went to school and I don't know what's happening so it must be a hovering helicopter and the govermnet is trying to cover it up just like they covered up rosswell. I will pray for all u to understand someday If you dont I will laugh when you burn in hell.

ps I'll give you a hint, it has some helium in it like that what helps dragons fly. As for the rest I will only tell you -INDUCTIONFLUX TRANSMOGRIFICATION- Go educate yourselfs. www.inductionfluxtransmogrification-truth.com (http://www.inductionfluxtransmogrification-truth.com)

stansdds
06-02-2007, 05:04 AM
Yeah, but the U.S. has ultra-top secret black helicopters that make no noise. They use them to spy on me. Honest! Just the other day I saw a bunch of CIA guys in my yard. I think they bugged the bird bath and I'm sure they bugged the kitty litter pan. http://forums.ubi.com/images/smilies/35.gif

raaaid
06-02-2007, 07:32 AM
but if the shutter speed is so fast and the framerate slow, whats in the black part?
in fact does pc image has a flickering black image?

i mean if each frame shutter is .001 s and there are ten frames each second that makes a lot of missing time with no image

tigertalon
06-02-2007, 08:05 AM
Originally posted by Zeus-cat:
Lurch1962 is correct, the shutter speed is indeed quite fast as the rotors are not blurry. If the shutter speed were slow the rotors would be blurred.

It can also be seen that shutter is some kind of central-symetric method, not like traveling from left to right or from bottom up, as the blades are not 'bent' weirdly as it usually happens with such shutters. Two polarisers maybe...


Originally posted by raaaid:
but if the shutter speed is so fast and the framerate slow, whats in the black part?
in fact does pc image has a flickering black image?

i mean if each frame shutter is .001 s and there are ten frames each second that makes a lot of missing time with no image

Each image was taken in 0,001 sec, separated by 0,1 sec, but they are shown shown for the ,1 sec each. You are essentially looking at a slideshow with 10 pics per sec (in your example). The time of exposure has nothing to do with the frequency of framing, it depends on lighting, film (ASA), aperture etc...