Eine Kleine Nichtmusik

Witty and pertinent observations on matters of great significance OR Incoherent jottings on total irrelevancies OR Something else altogether OR All of the above

Thursday, October 21, 2010

How It Works

Following on from this xkcd cartoon.....

...we reach this page....

....and finally this utterly brilliant explanation.

So that "This Way Up" sign on the Kulula plane isn't necessary after all.

2 Comments:

At 22 October, 2010 19:55, Blogger JoeinVegas said...

but the second explination totally ignores the first, which says it's the air flowing downwards at the back that produces the lift. Which one is right? (or are both?)

 
At 31 October, 2010 01:22, Blogger Rob said...

Well if the plane is going up some mass must be being pushed down to achieve that. Air gets shoved down in three ways: if the angle of attack is greater than zero the slope of the wing pushes it down. You can get that to work updide down by shoving the stick forward. If the air going over the top of the wing goes faster than the air underneath then you get that "curvature of streamlines" business, which is analogous to a wavefront bending when one end is slowed down (eg light refraction). This one works even at zero angle of attack (though isn't much use upside down). Finally there's the vortex shedding stuff. It all happens at once, I think.

 

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