Hobo Jungle

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webenda
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Re: Hobo Jungle

Postby webenda » Fri Feb 26, 2016 3:08 am

sarge wrote:OK. Go for it.

Understand though I'm still in need of convincing you can confidently give a Murph a wingspan with no other parametres defined:


I went for it. My mind seized on the idea of a simple correlation between span and lift when you challenged me. The "Span Theory" proved false. I am giving up Theoretical Aeronautics and going back to running toy trains around in a circle.

All the birds in Rhett Allain's wing span study had a suitable wing area for their weight and flying speed. He just noticed a correlation between wing span and bird weight and focused on the span parameter only.

Rhett Allain is an Associate Professor of Physics at Southeastern Louisiana University. I don't think for a moment he is ignorant of the lift formula or the fact that area is needed to generate lift.

I thought I could create a formula for a string wing that moved enough air to fly Murph high in the sky, but found out differential pressure over the wing area is a significant factor in lift and cannot be ignored. That and acceleration of air downward are factors that explain how a wing works.

Here is a nice photo showing the downward flow of air pushing a trough in the top of a cloud after an airplane passes over. In the picture, the Cessna Citation has just flown above a cloud deck shown in the background. The downwash from the wing has pushed a trough into the cloud deck. The swirling flow from the tip vortices is also evident. Area of a wing is also very much a part of calculating the mass of air accelerated downward. Span alone is does not contain enough information to give a clue about lift.

Image

"The real details of how an object generates lift are very complex and do not lend themselves to simplification."
--NASA
----Wayne----

Back when I was growing up, if you didn't start someth'n, there wouldn't be noth'n.
--Merle Haggard

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webenda
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Re: Hobo Jungle

Postby webenda » Wed Mar 02, 2016 9:29 am

Happy Weights and Measures Week 2016!
http://nist-takingmeasure.blogs.govdeli ... week-2016/
----Wayne----

Back when I was growing up, if you didn't start someth'n, there wouldn't be noth'n.
--Merle Haggard

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MurphOnMillerAve
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Re: Hobo Jungle

Postby MurphOnMillerAve » Wed Mar 02, 2016 10:19 am

webenda wrote:....
"The real details of how an object generates lift are very complex and do not lend themselves to simplification."
--NASA

Actually, I thought is was a simple matter; that is, one made the air atop the wings move faster than the air below wings, decreasing the air pressure above them and, thus, the air pressure below lifts the plane up in the air.

Now, the actual physical machinery involved to effect that lift is a whole lot more complicated a matter, but the principle is simple: less air weight/pressure atop the wings = lift from the underside air pressure, and up we go!. Eh? :D Huh? Wha'? 8)

For example, to demonstrate such a simple principle to my eighth grade classes back in the simpler '70's, I used to take a sheet of writing paper, hold it horizontal and parallel to my mouth, blow across the top of it, and voila! The paper lifts its tail-end and arises as though in flight. Demo over. Smiles and "Ah's!! all around. Try it. You'll like it.

I'm jus'sayin' . :mrgreen:

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webenda
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Re: Hobo Jungle

Postby webenda » Wed Mar 02, 2016 4:41 pm

Bernoulli's Principle
Blowing on a piece of paper.jpg
Blowing on a piece of paper.jpg (24.88 KiB) Viewed 3149 times

Nice demo of Bernoulli’s principle Murph. Bernoulli's principle states that fluids in an area moving faster than the surrounding area possess less pressure.
Prior to blowing across the paper air molecules are moving with random vectors, an equal number striking each side of the paper.
Piece of Paper.png
Piece of Paper.png (7.24 KiB) Viewed 3149 times

When blowing on one side of the paper air molecules in the stream of air from the mouth are vectored in a stream away from the mouth. Very few of them strike the paper.
Piece of Paper Blowed on.png
Piece of Paper Blowed on.png (5.66 KiB) Viewed 3149 times

Air molecules under the paper have random vectors many of them striking the paper. The force of those strikes pushes the paper up.

When used to explain airfoil lift the experiment leaves out one little detail—air blows under a wing in flight, not just across the top.
Piece of Paper wing.png
Piece of Paper wing.png (5.67 KiB) Viewed 3149 times
----Wayne----

Back when I was growing up, if you didn't start someth'n, there wouldn't be noth'n.
--Merle Haggard

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MurphOnMillerAve
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Re: Hobo Jungle

Postby MurphOnMillerAve » Wed Mar 02, 2016 5:01 pm

Oh. OK.

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webenda
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Re: Hobo Jungle

Postby webenda » Wed Mar 02, 2016 5:23 pm

MurphOnMillerAve wrote:Oh. OK.

OK? Don't you wish to argue that a flat piece of paper is not a very good airfoil? And argue a good airfoil has a curved upper surface that forces the air to flow faster over the curve with a resultant reduction in pressure?
Attachments
Write Flyer Airfoil.jpg
Write Flyer Airfoil.jpg (19.19 KiB) Viewed 3139 times
----Wayne----

Back when I was growing up, if you didn't start someth'n, there wouldn't be noth'n.
--Merle Haggard

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MurphOnMillerAve
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Re: Hobo Jungle

Postby MurphOnMillerAve » Wed Mar 02, 2016 6:13 pm

webenda wrote:
MurphOnMillerAve wrote:Oh. OK.

OK? Don't you wish to argue that a flat piece of paper is not a very good airfoil? And argue a good airfoil has a curved upper surface that forces the air to flow faster over the curve with a resultant reduction in pressure?

OH yes! I forgot that part. :oops: Good point, indeed! :D (You're a generous man.)

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robert.
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Re: Hobo Jungle

Postby robert. » Wed Mar 02, 2016 6:59 pm

0AA9_zpsnh3idxo1.jpg
I spend entirely too many hours a day tying my shoes

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webenda
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Re: Hobo Jungle

Postby webenda » Wed Mar 02, 2016 7:37 pm

Looks like we are both wrong Murph. Seems lift is caused by our dreams.
----Wayne----

Back when I was growing up, if you didn't start someth'n, there wouldn't be noth'n.
--Merle Haggard

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MurphOnMillerAve
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Re: Hobo Jungle

Postby MurphOnMillerAve » Wed Mar 02, 2016 8:38 pm

Such is life, my brother.
Murph

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Rufus T. Firefly
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Re: Hobo Jungle

Postby Rufus T. Firefly » Thu Mar 03, 2016 7:55 am

MurphOnMillerAve wrote:Such is life, my brother.
Murph


The stuff that dreams are made of...
Do not wait to strike till the iron is hot; but make it hot by striking.

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Rufus T. Firefly
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Re: Hobo Jungle

Postby Rufus T. Firefly » Tue Mar 08, 2016 8:05 am

http://www.pillsbury.com/holidays-celeb ... NwodsyMG8Q

What!!!!!! :shock: :shock: :shock: :shock: :shock:

Yet another sign that the end of civilization as we know it is eminent........... :?
Do not wait to strike till the iron is hot; but make it hot by striking.

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rogruth
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Re: Hobo Jungle

Postby rogruth » Tue Mar 08, 2016 9:05 am

Strange. Well at least odd. :D
roger

I support thread drift.
If God didn't want women to be looked at, He would have made 'em ugly. RAH

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robert.
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Re: Hobo Jungle

Postby robert. » Tue Mar 08, 2016 12:35 pm

They need more raisins :lol: . I think those cookies were made by the guy i saw on the beach.
I spend entirely too many hours a day tying my shoes

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MurphOnMillerAve
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Re: Hobo Jungle

Postby MurphOnMillerAve » Tue Mar 08, 2016 1:22 pm

And all of that makes me wonder how long aliens have actually been visiting this planet. . :mrgreen:
Last edited by MurphOnMillerAve on Tue Mar 08, 2016 2:15 pm, edited 1 time in total.


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