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Comment by 1970-01-01 | Hacker News Reader

1970-01-01

Pretty much this. Also, we still do not 100% understand aircraft lift and Bernoulli's principle.

What are you talking about?? We completely understand aircraft lift. Bernoulli's principal is a nearly irrelevant footnote that gives a small boost to efficiency.

Aircraft lift is caused by the upward angle of the wings forcing air downwards as the jets move the plane horizontally forwards. This "angle of attack" is usually very small so it's hard to perceive with the naked eye when looking at a commercial aircraft.

That's not totally correct. See here:

https://www.grc.nasa.gov/www/k-12/airplane/wrong2.html

It says it in the article. Lift is created by turning a fluid. Just as a spoon in a faucet, it’s all how you “throw” the fluid in the direction opposite the direction of lift. This is angle of attack.

The year is 2312, and we still have to combat the Bernoulli-airfoil misinformation. Even though all you have to do is stick your hand out of the window of a self-driving drone and twist it around a bit.

This sounds like an XKCD comic!

https://xkcd.com/803/

I find it hilarious that in the future everyone is more capable than the present at inventing things and also simultaneously these same people are incapable children who can’t use anything manual. It’s concerning that people dream that way.

>> do not 100% understand aircraft lift

Do you mean turbulence? There are some blank spots there but we have very good equations to approximate the behavior, equations good enough for practical aviation.

From what I understand, the challenge is the following: Even though we know precisely how to calculate the lift generated by a wing, all attempts to reduce those equations and their predictions to "ELI5" arguments leads to incorrect explanations.

Basically: We can explain aircraft lift to a college student, but not to a 5 year old. Or, we can explain aircraft lift using equations, but not using informal arguments.

Air pushed down. Plane go up. More air pushed down, more plane go up. Most everything else is about preventing and controling turbulence, keeping the air moving smoothly around stuff.

Or the physics of lithium ions, which is why sometimes a new battery design will just spontaneously catch fire (because the time it takes it to denature into something dangerous exceeds the time the designers spent on practical testing).

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