Jump to content

Left and right hand threads, and where you live- A dilemma


Paul Marsh
 Share

Recommended Posts

Nothing to do with threads getting loose but......

In 1962, Ascher Shapiro, an expert in fluid mechanics at the Massachusetts Institute of Technology who died in 2004, ran an experiment showing that the Coriolis force does affect water drainage, but the rotational effect is so small that it's overshadowed by other factors, such as the direction that water enters a basin or the shape of the basin (which is a function of how the toilet-maker designs the bowl and flush mechanism).

Shapiro began his experiment by filling a large, shallow dish with water (two metres across and 150mm deep), making sure that the water entered the dish with a clockwise swirl, the opposite direction you'd expect it to turn in the Northern Hemisphere. He covered the dish with a plastic sheet, which removed any air drag, and let the water stand for 24 hours to negate its initial spin. When Shapiro first unplugged a drain at the bottom of the dish, he didn't notice any rotation to the water as it drained. However, after some time the water eventually began to swirl counterclockwise, though at a slow rate.

A few years later, another research team at the University of Sydney showed the opposite to be true in the Southern Hemisphere.

.... the people doing the demo with a small bowl / bucket of water at the equator are fakes, even when it was filmed by Michael Palin for the BBC embarrassed

Link to comment
Share on other sites

Advert


Posted by WolstonFlyer on 28/09/2013 09:15:08:
Have a look on YouTube at videos of people pouring water down a plug hole at the equator, there are lots of examples to look at. The water does seem to change direction or is it a trick?????.


***Link***

Trick. Notice how he puts his hand in the water - supposedly to steady it. Then as he takes his hand out he rotates it slightly starting the water moving in the direction he wants it to go. Except for the final time on the equator when he lifts it out cleanly.

Link to comment
Share on other sites

Very interesting discussion, but to return to the original problem -wing bolts unscrewing themselves if anyone remembers-
you could always make the wing bolts captive in the wing by wrapping a tiny rubber band around the bolt. Assuming there is a bit of a gap between the wing and the captive nuts it wont need to be removed. Otherwise just link the bolts together with a rubber band after flight.
Link to comment
Share on other sites

Posted by Ponty Bri on 28/09/2013 14:27:57:

What a great forum this is , so entertaining, nothing to do with flying mind you. Up to now I believed it was all to do with the hemisphere.

Brian

That's why I brought it up. Suppose the original topic is model related, but the water issue is also connected to the original topic, be it fluid dynamics rather than oscillation frequency. We can get to the Chaos Theory, but gravity is playing an active part in both fields - therefore doesn't fall under Chaos Theory, just bad luck when your wings fall off in the air (trust me - I know!). Again gravity plays a part when the model crashes down, but which way does the fuselage spin?crying

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

 Share

×
×
  • Create New...