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ArcticMyst Security by Avery

Helicopter flies without moving the main blades, Or maybe not.

piferal

piferal

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Haha, obviously this is not true, but it may seem :D

For those who do not know, I tell you after, how and why they do this, although it is quite evident anyway.

 





Elektrotechniker

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Does it have to do with the framerate of the camera and the speed the blades are turning around?
 
piferal

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Yes, of course, is correct :beer:

But why do this? It is easy ;)
 
BShanahan14rulz

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Perhaps it is to study the effect of drag on the blades of a helicopter which is doing something other than just hovering or flying in one direction at a constant speed.
 
piferal

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BShanahan14rulz said:
Perhaps it is to study the effect of drag on the blades of a helicopter which is doing something other than just hovering or flying in one direction at a constant speed.
Click to expand...

The first answer as Silvershot said, is, a radio wave signal is coupling the shot time of the camera with the rotation of the rotor to synchronize them.

Well, not that in this case, this allows to visualize efforts and deformations of the blades during exercise testing in real conditions of flight.

The effect is nice anyway.

Silvershot said:
Wait, are you saying there is another way to achieve this effect?
Click to expand...

No, what I mean is, why do this, for what reason do this.

Maybe it's because of my bad English.

Edit: But at your question, yes, it could also make with a synchronized strobe light, although in this particular case with a helicopter,
would not be so easy to visualize and put into practice.

An example of inspection of a rotating shaft with a strobe light.

 
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BShanahan14rulz

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The method with the strobe light, i.e. strobing the light source instead of "strobing" the light imaging unit can be viewed with your eyes alone, too :)
 
piferal

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BShanahan14rulz said:
The method with the strobe light, i.e. strobing the light source instead of "strobing" the light imaging unit can be viewed with your eyes alone, too :)
Click to expand...

Yes, of course ;)

This method reminds me the se-tup of the older car engines, well, I do not know how to say this correctly in English :D
 
Dr_Evil

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piferal said:
Yes, of course ;)

This method reminds me the se-tup of the older car engines, well, I do not know how to say this correctly in English :D
Click to expand...

You're thinking of a timing light. You'd hook it up to a power source and there would be another cable you would hook to the #1 cylinder spark plug cable. The light was usually aimed somewhere near the crankshaft pulley. You'd see a mark on the pulley when the strobe went off. The number that the mark was next too would indicate how many degrees before or after the timing was set at. You could adjust the distributor while watching the timing if you were careful enough. Otherwise you'd get zapped.

stealth2.jpg


Cool video though. I've never seen one where the blades stayed "still" quite like that.
 
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Tech_Junkie

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Actually its the harmonic dampener, not the pulley. It absorbs the vibrations of the crankshaft. :whistle:
 
Tech_Junkie

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piferal said:
Yes, they are words too technic and I do not know their name in English to explain it, but more or less as you say,
is to Correct ignition timing by firing the spark plug to ignite air and fuel in the cylinder at the best precise instant.
Click to expand...

It controls the air/fuel valve in the head to let as much air/fuel pass as possible, then close the valve. This way there is a maximum amount of air/fuel in the cylinder when the plug fires.
 
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