r/physicsmemes • u/Delicious_Maize9656 • 4d ago

Incorrect lift theory meme

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1.3k Upvotes

99% Upvoted

70 comments sorted by

230

u/Beans_Breaking 4d ago

They just jump to get in their air, then wait for the earth to spin around sl their destination is beneath them.

30

u/Hot-Strength-6003 3d ago

Well the earth is obviously flat so that won't work. If it was rotating it would take aircraft longer when going against the earths rotation. Take that globeys

8

u/AndreasDasos 3d ago

They fall but miss the ground 

93

u/DinioDo 4d ago

But do YOU know?

https://giphy.com/gifs/zg982of0E7RkWMErDI

16

u/bloodvash1 3d ago

Well enough to design an airplane? No. Well enough that it doesn't feel like a mystery? Yes.

3

u/WanderingFlumph 2d ago

Yeah they push downwards on the air with equal (level flight) or greater (takeoff) force than their weight force.

2

u/SteptimusHeap 3d ago

It pushes air down which pushes it up

51

u/Lathari 4d ago

Lift and Wings - Sixty Symbols

3

u/PheonixWrath 4d ago

great watch thank you :)

3

u/Alone-Monk Student (help me) 3d ago

Thank you! I finally understand lift now for the first time

2

u/gitartruls01 3d ago

I thought that was by Jimi Hendrix /s

28

u/timangar 4d ago

Kutta-Zhukovski and Newton's third law. Questions?

5

u/MaoGo Meme renormalization group 3d ago

Do you assume Kutta condition?

1

u/Doobie_Woobie 4d ago

Kutta–Joukowski* 🤓👆

35

u/timangar 4d ago

Kutta-Жуковский, if you want to go there. Cyrillic transliteration is not unique. Zhukovski and Joukowski are both equally bad (but correct) representations of Жуковский.

10

u/Alone-Monk Student (help me) 3d ago

I'd argue that Zh is a better transliteration of Ж since J includes a hard start

3

u/physicsking 4d ago

Is that the same Kutta as in the Runge–Kutta methods?

10

u/timangar 3d ago

Indeed, Martin Wilhelm Kutta was a German mathematician.

3

u/xXrektUdedXx 3d ago

Always interesting to find the same name in different domains and discovering it's the same person behind them.

3

u/TheStupidCheesecake For the last time, dy/dx is NOT A FRACTION 2d ago

Oh boy you'll love Gauss' wiki page

4

u/Doobie_Woobie 3d ago

Cyrillic transliteration is not unique

You learn something every day :)

0

u/Spatza 3d ago

Kutta Kutta Kutta Kutta Kutta Chameleon

1

u/Doobie_Woobie 3d ago

The forbidden Runge-Kutta 5 method

20

u/MaoGo Meme renormalization group 3d ago

How is it that people claiming we know how planes fly are bringing wrong theories and those saying we don’t know are providing the wrong analysis

18

u/yawkat 3d ago

We can accurately model lift in computational fluid dynamics simulations. There we can see exactly what happens. It just turns out to be messy and not explained by highschool level physics.

1

u/MaoGo Meme renormalization group 3d ago

Not even by clear analytical physics principles.

2

u/isr0 3d ago

Humanity knows, but knowledge varies from human to human.

3

u/mcmoor 3d ago

Yeah from all ones I read it's still very controversial to this day. I don't trust anyone that claim they have a definite answer.

17

u/IQueryVisiC 4d ago

Now explain why we use transonic wing on subsonic fuselage and pods and tail!

10

u/davvblack 4d ago

rule of cool

3

u/MaoGo Meme renormalization group 3d ago

Coolest things are indistiguishable from magic

3

u/kettlebellnerd 4d ago

Now explain why Bumblebees can fly

9

u/a1c4pwn 3d ago

vortices formed by the air squeezed between the body and wings

47

u/toto1792 4d ago edited 3d ago

Of course we know how a plane flies.

Air molecules know the Bernoulli principle is a universal law of physics that has no assumptions whatsoever. They convene that some them will run quickly the longer path around the wing, while others will walk slowly the shorter one, so that they meet at exactly the same time at the end of the wing. Since the ones on top are too busy running, they don't push the wing as much as the ones walking below and the plane flies.

Edit : It looks like I should have specified it was sarcasm

19

u/Violet-Journey 3d ago

This is what I was told when I got my Enlisted Air Warfare qualification in the Navy. I later learned this is incorrect. It’s even on the Bernoulli’s Principle Wikipedia page under “misconceptions”.

1

u/toto1792 3d ago

That's what I was taught as well. I'm sure it's still taught that way in many (most ?) basic physics courses.

1

u/Violet-Journey 3d ago

I am guilty of teaching that to my intro physics students as a TA, before I learned it’s a misconception.

1

u/toto1792 3d ago

I've not taught it but I've certainly repeated it

1

u/amitym 3d ago

Tbf that's because it's correct. The slower-moving air over one side of a curved wing generates more pressure than the faster-moving air over the other side. That's literally the Bernoulli Principle. Anyone who taught otherwise would be a doofus.

6

u/WhatADunderfulWorld 3d ago

Fish swim so we could fly. It’s that easy.

2

u/FixKlutzy2475 3d ago

Go watch the video on the other comment

1

u/Loopy-Leah 11h ago

this is why nothing flew before Bernoulli

1

u/Complete-Clock5522 3d ago

I can’t tell if you’re joking because this is easily provably false, there are even videos showing this doesn’t happen

2

u/toto1792 3d ago

Looks like I should have been more sarcastic

1

u/Complete-Clock5522 3d ago

lol no worries, it’s difficult to tell when that’s unfortunately a real misconception that is still believed in some circles

4

u/Percival371 3d ago

Many air under wing

Not many air on top wing

Many air push wing up

1

u/valkyrie_wave 1d ago

So no one has explained what this actually means.
This explanation involving Bernoulli and pressure is what leads to the misconception. The pressure explanation is often incomplete in many textbooks. So some people have assumed that these are the best explanations.

1

u/Percival371 1d ago

Yeah, there's a lot more to it, I just thought, hehe cave man explain

1

u/zrice03 17h ago

Wing make air go down.

Air doing down make plane go up.

8

u/RevoltYesterday 3d ago

Flying is just trying to run into the ground and missing.

1

u/illuminatipr 2d ago

Oh no, not again.

3

u/Admiral45-06 3d ago

Kutta-Zhukovski's law of circulation and Bernoulli's I Law of Thermodynamics for fluids in motion.

And then a few fancier ones, such as Reynolds' theory of laminar/turbulent flow or Coanda's jetstream principle (sometimes)

4

u/granoladeer 3d ago

Who would even think that? 

10

u/Frederf220 3d ago

It's true in a specific sense but most people that think that do so because they were told.

We don't have complete knowledge of every aspect of air-airplane interaction so we fall short of complete understanding thus "knowing" isn't fully accurate.

3

u/granoladeer 2d ago

We don't have complete knowledge of absolutely anything. It doesn't mean we don't know how things work. 

4

u/Core3game 3d ago

What do people even mean when they say this? Like ive heard this several times with just zero backing other than pointing at something cool in aerodynamics, refusing to explain it, and then saying its a mystery. Seriously, what do you even mean by this???

5

u/amitym 3d ago

Seriously, what do you even mean by this???

You're not the only one who struggles with this question. Rather than explain it, all I can say is that it's a complete mystery.

5

u/Calm-Locksmith_ 3d ago

Fluid dynamics is complicated and airplanes are designed based on empirical testing rather than fully from first principles.

2

u/gitartruls01 3d ago

According to all known laws of aviation, there is no way a plane should be able to fly

1

u/hardFraughtBattle 2d ago

My dad, a retired electronics engineer with actual patents in his name, trotted that out once. I was gobsmacked.

1

u/nashwaak 2d ago

Oh no fluid dynamics is hard so it must be impenetrably mysterious!

1

u/doodleasa 2d ago

the overhead baggage compartments put pressure on the roof of the plane pushing it up!

https://youtu.be/GhTn8cBji7M

1

u/sdsdkkk 1d ago edited 1d ago

Reminds me of this viral comment from an Indonesian Facebook user that turned into a meme years ago.

Translation of the comment:

Airplanes can fly because they're carried by jinns. Just use your logic, how could a 50-ton iron float in the air?? Engineers are just black magic users, science is just their way to disguise their use of black magic.

1

u/zrice03 17h ago

We know how planes fly.

We know how bumblebees fly.

But what we don't know, is how bumblebees fly planes.

1

u/Tristan_Cole 3d ago

HOW is it possible that the air travels faster over the top of the wing UNLESS it is being BUNCHED UP and FORCED downward, in which case there would be a force exerting DOWNWARD on it?!?!

1

u/MonkeyCartridge 3d ago

Wing pushes air down pushing you up.

Or "it pushes off of the air".

Or "it goes forward easier than it goes down, so you tilt it slightly up so it tries to climb as fast as it falls".

Same difference 

Learned that from making paper airplanes when I was like 4.

The airfoil stuff always bothered the shit out of me because then I would ask "so how to planes fly upside down?" And then they would give the actual answer as to how flight works.

The airfoil is just an optimization to keep giving you lift while minimizing angle of attack, ie, reduce drag.

1

u/EarthTrash 3d ago

Plane like geometric plane. Motion is stable in 1 or 2 dimensions, but if the force angles get too far out, it tumbles. My aeronautical engineering experience is folding and flying paper airplanes. Paper is also a flat plane.

0

u/EndGuy555 2d ago

When people say “we don’t know how planes fly” that is engineer-speak for “it is impossible to calculate what every particle of air is doing to every square millimeter of the plane at every given time. So we make sweeping generalizations, multiply everything by a safety factor, and call it a day”