What is the rotating disk ... Called?

[a1call]

What's the name of the rotating disk with multiple view holes called?
It is used to see rotating parts in slow motion/in-static.

In particular I am looking for good quality video of propellers in action, should anyone care to browse.

Thanks in advance.

[Perikles]

Do you mean the zoetrope?

[NEOWatcher]

Stroboscope?

[a1call]

Thanks again for the relies.
The word I was looking for was indeed stroboscope.
This board never fails to deliver.
Invitation to post related links to footage/pictures stands.

Thank you.

[orionjim]

Thanks again for the relies.
The word I was looking for was indeed stroboscope.
This board never fails to deliver.
Invitation to post related links to footage/pictures stands.

Thank you.

You can find many examples on YouTube

For example a strange effect of an airplane propeller
http://www.youtube.com/watch?v=LVwmtwZLG88

Or a helicopter
http://www.youtube.com/watch?v=rVSh-au_9aM

Jim

[NEOWatcher]

For example a strange effect of an airplane propeller
http://www.youtube.com/watch?v=LVwmtwZLG88

Obviously either the Australian or New Zealand air force's boomerang defense.

[a1call]

You can find many examples on YouTube

For example a strange effect of an airplane propeller
http://www.youtube.com/watch?v=LVwmtwZLG88

Or a helicopter
http://www.youtube.com/watch?v=rVSh-au_9aM

Jim

Thank you orionjim for the examples.
Another one for the record:

http://www.youtube.com/watch?v=Y3VsP...e_gdata_player

I can't help but assume that these are produced by filming with slow motion cameras then editing out all frames other than synced ones. They seem too perfect.

[NEOWatcher]

Thank you orionjim for the examples.
Another one for the record:

http://www.youtube.com/watch?v=Y3VsP...e_gdata_player

I can't help but assume that these are produced by filming with slow motion cameras then editing out all frames other than synced ones. They seem too perfect.

All it takes is the frequency of the frames, and the frequency of the movement to be harmonics (or near harmonics) of each other.
In that video the propellers do have some visible movement.

[publiusr]

I'd like to see digital camera, camcorder and film of the same craft to see how different media have different artifacts.

[a1call]

On a related note:
As I understand it an asymmetric tear drop profile is more efficient in providing lift than an angled blade.
As I understand most airplane wings as well as propellers have a tear drop profile to take advantage of the better performance.

*- Why don't all fan blades, boat propellers and impellers have a tear drop blade profiles?

Thanks to all who posted.

[NEOWatcher]

*- Why don't all fan blades, boat propellers and impellers have a tear drop blade profiles?

Bernoulli's equations have speed in the numerator. So; the effect is smaller with lesser speeds.

Add to that, when moving water, the effect may cause cavitation in which you end up trying to move air instead of water which is significantly different.

Fans are trying to move air, not provide propulsion.

[HenrikOlsen]

Oh, and incidentally, falling drops of water are not teardrop shaped.