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No One Can Explain Why Planes Stay in the Air

Desertfox

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I remember my aerodynamics professor in college telling us that answering any question with "magic" would get you at least partial credit.
 

totoro

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Dont the both theories contribute to the generated lift? I guess one could argue about the ratio, which principle generates more lift, and how much more.
 

MihoshiK

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sferrin

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If nobody knows why planes stay in the air how is it that they can design aircraft to do so? (And seriously? Aircraft stay up because they force air down.)
 

Desertfox

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We know how to make airplanes fly, we don't know exactly why they actually do.
 

rooster

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This is like saying we don't understand why billiard balls behave as they do. Of course we do, to a point, but what we don't yet understand is where the masses of the particles originates from that form atoms and molecules. The Standard Model still requires physicists to manually plug into the equations the masses that are found to exist via experiments. No proven theory yet explains mass. Higgs is a good attempt.The same forces that explain billiard balls explains air molecules on the bottom of a lifting surface pushing it upwards. Newton, Lagrange, and Hamilton rule classical mechanics. If you want to get philiosphical about mass and momentum and acceleration then start reading Mach. Fluid mechanics is why airplanes fly... Little tiny microscopic billiard balls on the bottom of wings push the wing up. L=T-V. Derivable from simple calculus and using Newtons f = ma.
 
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Sundog

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As an aeronautical engineer, we do know why airplanes fly. There are multiple ways of analyzing them, but it isn't F***ing magic. I really hate stupid articles like the one referenced. Apparently the people who wrote the article don't know a damned thing about circulation, or the Kutta-Jukowski theorem. Different "approaches" offer different data based on what is being sought; as they noted, Bernoulli and Newtonian Mechanics. They're both valid. They could also perform a Trefftz plane analysis,etc.

BTW, for simplicity, think of it like this. F=MA. The airplane stays up by throwing air down. Equal and opposite reactions. The different mathematics/physical approaches are just to reveal different data sets based on what we're seeking to understand about the vehicle's performance.
 
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icyplanetnhc

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My intermediate fluid mechanics TA said that if someone asks for a simple one word answer to describe, it's "circulation". I guess in the context of Kutta-Joukowski he's not wrong...

Still remember having to do those lifting line theory derivations. Good times.
 

galgot

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As an aeronautical engineer, we do know why airplanes fly. There are multiple ways of analyzing them, but it isn't F***ing magic. I really hate stupid articles like the one referenced. Apparently the people who wrote the article don't know a damned thing about circulation, or the Kutta-Jukowski theorem. Different "approaches" offer different data based on what is being sought; as they noted, Bernoulli and Newtonian Mechanics. They're both valid. They could also perform a Trefftz plane analysis,etc.

BTW, for simplicity, think of it like this. F=MA. The airplane stays up by throwing air down. Equal and opposite reactions. The different mathematics/physical approaches are just to reveal different data sets based on what we're seeking to understand about the vehicle's performance.
I remember reading the way a plane fly is more by being "sucked" up by the depression created above the wing by the forward motion than by the pressure under it (pushing air down). Did I understood correctly what I was reading :) ?
 

rooster

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As an aeronautical engineer, we do know why airplanes fly. There are multiple ways of analyzing them, but it isn't F***ing magic. I really hate stupid articles like the one referenced. Apparently the people who wrote the article don't know a damned thing about circulation, or the Kutta-Jukowski theorem. Different "approaches" offer different data based on what is being sought; as they noted, Bernoulli and Newtonian Mechanics. They're both valid. They could also perform a Trefftz plane analysis,etc.

BTW, for simplicity, think of it like this. F=MA. The airplane stays up by throwing air down. Equal and opposite reactions. The different mathematics/physical approaches are just to reveal different data sets based on what we're seeking to understand about the vehicle's performance.
I remember reading the way a plane fly is more by being "sucked" up by the depression created above the wing by the forward motion than by the pressure under it (pushing air down). Did I understood correctly what I was reading :) ?
So you're saying that vacuum can do work. No, vacuum by definition cannot do work. "Nothing" is not capable of work. There are quantum properties of vacuum in the microscopic realm that do not apply to macroscopic objects. In the world of every day objects it takes "something" to perform work.
 
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