Watch a camera and helicopter cycle in perfect synchronicity

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I was going to say that a typical helicopter rotor speed seems to be on the order of 400-500 rpm, and I don’t know many people who accidentally or customarily take video at 7-8 frames per second. Then I realized, I guess it could be 30 frames per second, and in each frame it’s actually the next rotor blade facing us. Which I actually think is even cooler.


the helicopter says “I must go, my planet needs me.”


Not quite as exciting, but I’ve had the same thing happen on dashcam videos with other cars’ wheels.

Glitch in the Matrix! Prepare for a reboot! May also fix “Trump Bug” during down time!


Nice try, DOD. We know Project Bluebook tech when we see it.

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I have a really stupid question, and it’ll probably be embarrassing, but I’m old enough at this point where I think people might just feel sorry for me. :grin:

As it moves away, it starts to move. Is that because the pilot is increasing power at that point and they are spinning faster, or is there something about the distance that changes the relationship?

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I don’t think that’s a stupid question at all. My guess it’s actually the blades slowing down slightly after the ascent, as the helicopter will need less power to maintain a steady altitude.


While the second video does demonstrate blades moving out of sync with the camera’s shutter speed (as you can see them rotating), the propeller blades looking warped / curved is primarily due to the camera’s use of a rolling shutter.


Synchronization, not synchronicity. (Unless they are Police fans.)

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I watch a lot of model aircraft POV videos, and that is a genre that could really benefit from a camera that could synch with the prop speed. Probably too small a niche to have any marketing pull, though…

Let’s hope it doesn’t replicate itself!

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The shutter is not just in sync with the rotors, but it’s also very fast. Even if the blades were to be in the same position each frame, I’d still expect to see some motion blur and–if it had a rolling shutter–some “bending” of the blades. The fact that we see neither suggests that the shutter was open for a very short time, possibly because it was a very bright environment.

I’m also surprised the rotor speed was that constant. I know nothing about helicopters, but I would have guessed that the speed of the rotors varies significantly during take off.


Man, aerotech is getting better all the time; now they have rotor-fields to propel planes.

What will they think of next?

Another version… when you fly to the south Pole, the LC-130 aircraft never shuts off its motors. I first noticed this in my photo collection as its props aren’t aligned at pretty 45 degree angles, as they are when you land at McMurdo. The crew does the prop alignment by hand after you land.


Yeah, me too. To not visibly move at all must have meant the rotors were spinning at an incredibly consistent rate, even as it switched from vertical to horizontal movement. I would not have expected that.

This looks so weird.

Fake. I can tell from the pixels in the sky that he just photoshopped out the hand of god.

Shutters being a mechanical thing, and CCDs being solid state, I find the language used to explain this effect to be interesting. Not being a photography buff, Is the shutter speed of a digital camera an actual thing?