No One Can Explain Why Planes Stay in the Air

[rockytopva]

In Germany, one of the scientists who applied themselves to the problem of lift was none other than Albert Einstein. In 1916 Einstein published a short piece in the journal Die Naturwissenschaften entitled “Elementary Theory of Water Waves and of Flight,” which sought to explain what accounted for the carrying capacity of the wings of flying machines and soaring birds. “There is a lot of obscurity surrounding these questions,” Einstein wrote. “Indeed, I must confess that I have never encountered a simple answer to them even in the specialist literature.”

No One Can Explain Why Planes Stay in the Air

 

[zippy2006]

I have also found explanations of aerodynamic lift wanting, so this makes some sense.

 

[Willing-heart]

I have also found explanations of aerodynamic lift wanting, so this makes some sense.

“Aeronautics was neither an industry nor a science. It was a miracle.”
― Igor Sikorsky (Aviation pioneer)

 

[Halbhh]

In Germany, one of the scientists who applied themselves to the problem of lift was none other than Albert Einstein. In 1916 Einstein published a short piece in the journal Die Naturwissenschaften entitled “Elementary Theory of Water Waves and of Flight,” which sought to explain what accounted for the carrying capacity of the wings of flying machines and soaring birds. “There is a lot of obscurity surrounding these questions,” Einstein wrote. “Indeed, I must confess that I have never encountered a simple answer to them even in the specialist literature.”

No One Can Explain Why Planes Stay in the Air

This one though we can take advantage of the study of engineers and such since. The air flowing over the top of the wing must travel further, due to the shape of the wing. Consider: air molecules have temperature, which is really their kinetic energy of motion. If more of the temperature - motion for the air flowing over the top (vs air flowing under the bottom of the wing) is then forced to be in the direction of flight (parallel to direction of wing motion) then less of that over-top air's motion component can be perpendicular, meaning the air pressure of the air above the wing is then made to be lower then than air pressure under the wing. The pressure difference is then lift. (This reduced sideways pressure due to greater flow velocity is called the Bernoulli effect)

 

[Ophiolite]

Perhaps I can make a small contribution:

In the early 1970s I was flying over the South China Sea in a chartered DC3. Sitting next to me was a drunk American, employed as an oil and gas well cementer. At one point he nudged me and pointed out of the window at the propeller over the port wing. "You see that? You see that big fan? Do you know what that's for?" Intrigued as to what his explanation might be I allowed as how I didn't. "That's to keep the wing cool. If it wasn't there the wing would heat up, melt and fall off."

You just don't find that kind of in-depth information in aeronautical textbooks.

 

[Theophilus2019]

Like the writer above says, because of the shape of the wing as the wing moves through the air, the air above the wing has to travel further than the air under the wing. So the air above gets thinned, so the pressure below is higher, causing lift.

 

[SelfSim]

This one though we can take advantage of the study of engineers and such since. The air flowing over the top of the wing must travel further, due to the shape of the wing. Consider: air molecules have temperature, which is really their kinetic energy of motion. If more of the temperature - motion for the air flowing over the top (vs air flowing under the bottom of the wing) is then forced to be in the direction of flight (parallel to direction of wing motion) then less of that over-top air's motion component can be perpendicular, meaning the air pressure of the air above the wing is then made to be lower then than air pressure under the wing. The pressure difference is then lift. (This reduced sideways pressure due to greater flow velocity is called the Bernoulli effect)

Did you read the OP linked article?

 

[SelfSim]

No scientific theory is ever complete. They are contextual and provisional.

Why should these ones be any different from that?

 

[Halbhh]

Did you read the OP linked article?

No. But I had a physics professor in freshman physics who was pretty good. This isn't me coming up with why Bernoulli effect occurs. I'm pretty sure he explained it to us like this. Looking at the link, let me only comment that every physicist seems to have different ways explaining stuff. It's common that one will say something is not yet well understood and another would simply give an explanation.

 

[SelfSim]

No. But I had a physics professor in freshman physics who was pretty good. This isn't me coming up with why Bernoulli effect occurs. I'm pretty sure he explained it to us like this.

There are two main competing physical explanations.

In a nutshell:
The Bernoulli explanation: The flow along the top increases in speed, therefore decreases in pressure, and the resulting pressure difference creates a lift force.

The Newtonian explanation: Air is accelerated downwards so by conservation of momentum the wing is accelerated upwards. (Note here again that this is not (solely) the downwards deflection of the air by the bottom surface at a non-zero angle of attack but the downwards deflection of the air by the top surface at a zero angle of attack).

There are pros and cons either way. Your professor was probably only giving a freshman explanation .. don't fixate on freshman explanations .. move on (and read the article .. its a good one!).

 

[Halbhh]

There are two main competing physical explanations.

In a nutshell:
The Bernoulli explanation: The flow along the top increases in speed, therefore decreases in pressure, and the resulting pressure difference creates a lift force.

The Newtonian explanation: Air is accelerated downwards so by conservation of momentum the wing is accelerated upwards. (Note here again that this is not (solely) the downwards deflection of the air by the bottom surface at a non-zero angle of attack but the downwards deflection of the air by the top surface at a zero angle of attack).

There are pros and cons either way. Your professor was probably only giving a freshman explanation .. don't fixate on freshman explanations .. move on (and read the article .. its a good one!).

Same thing in different wording -- how is it the air overall motion is redirected? See? In the explanation I was laying out above, the question we'd perhaps go to next is how is it that the air molecules flowing over the top, and those flowing under also, are being made to have their average motion of the set of molecules redirected. See? I think of that as being from the collision with the shape of the wing. But this is all just mechanics way of thinking. Air molecules are little balls, with momentum-velocity. So, its the same explanation in both, to me, when you connect with that how the air motion is changed by the wing. We all have our own ways of fixating. I hope I'm fixating ok.

 

[Sabertooth]

No One Can Explain Why Planes Stay in the Air

(Maybe, you should wait until they all land before you call their physics into question...)

 

[sjastro]

"In pursuit of a discovery, the dedicated scientist will almost do anything.
The British physicist Lord Cherwell learned to fly in three weeks during World War I in order to put a plane into a dangerous spiral dive, and prove successfully, his solution to a problem in aerodynamics".

 

[Ricky M]

There are two main competing physical explanations.

In a nutshell:
The Bernoulli explanation: The flow along the top increases in speed, therefore decreases in pressure, and the resulting pressure difference creates a lift force.

The Newtonian explanation: Air is accelerated downwards so by conservation of momentum the wing is accelerated upwards. (Note here again that this is not (solely) the downwards deflection of the air by the bottom surface at a non-zero angle of attack but the downwards deflection of the air by the top surface at a zero angle of attack).

There are pros and cons either way. Your professor was probably only giving a freshman explanation .. don't fixate on freshman explanations .. move on (and read the article .. its a good one!).

And once again, it has to be one or the other. They can't both contribute. That would be sacrilege!

 

[Lady Donna Marie]

Mmmm. This doesn't make sense to me. There seems to be a mathematical equation for a lot of things.

Like, do A to get B = the outcome your looking aiming for.

The simple version is that a plane has to have the right materials to manage to stay up in the air accordingly. A plane has to have the right amount of force to defy gravity and that all depends upon the weight and materials used that built a plane and how much force it needs to get its self off the ground in the current weather conditions it experiences along with the weight of the air craft. A paper airplane easily floats in the air because the weight of the paper airplane doesn't not need a great force to get it going. It's light enough to fly with ease, but not so much in a controlled direction.

 

[NxNW]

If the force on the wing is upward, why can planes fly upside down?

 

[FrumiousBandersnatch]

If the force on the wing is upward, why can planes fly upside down?

They go into an upside-down 'dive'

 

[NBB]

If the force on the wing is upward, why can planes fly upside down?

Raw engine power.
and the 'newtonian' explanation above.

 

[SelfSim]

"In pursuit of a discovery, the dedicated scientist will almost do anything.
The British physicist Lord Cherwell learned to fly in three weeks during World War I in order to put a plane into a dangerous spiral dive, and prove successfully, his solution to a problem in aerodynamics".

What legend!
That's what I call "puttin ya money where ya mouth is"!

 

[SelfSim]

And once again, it has to be one or the other. They can't both contribute. That would be sacrilege!

Whatever do you mean there?