"Engineer debunks theory of Flight" 2

[rb1957]

http://www.smh.com.au/world/engineer-debunks-theory-of-flight-20120126-1qjrc.html

i was hoping for something more radical ... he's going back to the old myht that two molecules of air ahead of the wing join up again after the wing, the longer distance of the path over the wing measn it has to travel faster, ...

no, he says it's the shape of the wing causing lower pressure above ...
which from bernoulli means higher speed ...

 

[IRstuff]

Let's not bring THAT subject up again. It was beaten to death a couple of years ago here, when someone brought up the question of circulation. Moreover, the "professor" is promulgating a myth to "debunk" the other myth. His "explanation" uses pressure differential to "cause" lift, which, we know, is not correct either. If he had gone on to conservation of momentum, I might have gotten interested.

TTFN
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[KENAT]

If the curve is do damn important then why does a flat plate generate lift quit nicely if put at an appropriate angle to the airflow. Urggh.

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[KENAT]

Hang on, is this the clip

http://www.youtube.com/watch?feature=player_embedded&v=UqBmdZ-BNig

In the clip all he does is demonstrate that particles going over the top of the wing don't arrive at the back of the wing at the same time as those going under.

However, in the article the talk about curved 'wing' does not match what I was taught, or experiments we got to conduct.

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[GregLocock]

It is only the Sydney Morning Herald, which outsources its journalism and editing and printing. Some of the comments underneath are pretty funny (No my pen-name isn't John Shaw from Melbourne)



Cheers

Greg Locock


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[KENAT]

Well yeah, I was only going by the part in quotation marks, which I vaguely hoped was at least from the prof. Now it may be out of context but unless they really changed the wording or made it up then it doesn't look good.

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[FeX32]

I also was taught the "faster top - slower bottom" theory in uni.
I also vaguely remember one of the profs mention that the lift may have to do with the coefficient of drag at certain angles of attack. The higher the drag the more momentum is displaced. Then the lift can be derived from there, possibly.


Fe (IronX32)

 

[rb1957]

that's cause it is "faster on top", 'cause the static pressure is lower. the problem with the two molecules meeting up again is that i think it is a simplification for the masses.

 

[KENAT]

Pretty sure faster on top, slower on bottom is more than a theory, heck that video certainly suggests it.

It's the 'why' that still leads to debate.

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[IRstuff]

The faster implies a lower pressure, so it boils down to whether the pressure differential is enough to lift the plane. If it isn't, then that theory is wrong.

TTFN
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[KENAT]

Well, I was taking for example the demonstration of the pulsed smoke plumes - where that over the top clearly reached the rear of the wing before that going under the wing - as a reasonable indication that the air over the top is effectively traveling faster than that under.

So hence I'm pretty confident in the 'theory' that air over a lifting wing is traveling faster than that under it.

This was in response to FeX32's comment.

I wasn't getting as far as applying Bernoulli, and definitely wasn't straying into conservations of momentum or bound vortex territory etc.

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[berkshire]

Hell Yawll aint getting it, yonly get lift if th wing deflects air down equal to the weight of the plane an it don matter how it does that.

The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor

 

[btrueblood]

Horses, dead, beating.

 

[IRstuff]

Sounds like a mil std:
"Military Standard
Horses, Dead, Beating"

TTFN
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[FeX32]

So hence I'm pretty confident in the 'theory' that air over a lifting wing is traveling faster than that under it.

I'm not disagreeing with the theory. I would just feel more comfortable if we could relate it to a differential change in momentum somehow.
Anyways, I don't want to beat any horses to death, what did they ever do to us besides provide us with ample transportation for centuries.




Fe (IronX32)

 

[rb1957]

Horses, Dead, For the Beating Of ...

 

[IRstuff]

and glue

TTFN
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[FeX32]

glue? lol


Fe (IronX32)

 

[KENAT]

... and yummy French cuisine...

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[FeX32]

Ok, the glue and French cuisine went right over my head lol


Fe (IronX32)