I recently taught my 11-year-old nephew “how planes fly.” A bit oversimplified, of course, but words like camber and lift and circulation were tossed around along with Bernoulli’s principle.
Yes, there’s a bit of a myth around Bernoulli’s principle (faster moving fluids have lower pressure) and how much it matters for lift in plane wings. It came up in the conversation because I was trying to describe what air pressure is in general, and made an analogy to a pan flute (he plays flute in band).
Disclaimer: I’m an aerospace engineer, but I do not claim to be an expert on topic.
But for plane wings, the myth is really that the air above the wing moves faster because the curved surface is longer. That’s pretty much dead wrong, but is still in tons of textbooks. The air above the wing does move faster, but it’s because of a bunch of complicated physics that to be honest, I don’t really understand any more. I may have even been taught wrongly in college. But the result is that there is a velocity difference on a cambered wing even when it’s flat, and thus Bernoulli’s principle does apply, and there is a pressure difference giving you lift.
But that speed difference is mostly important at cruising altitude, when the wings aren’t angled, and it’s positively correlated with airspeed, so the thrust matters way more. When you’re climbing, the angle matters more. The camber (curvature) of the wing, the airspeed, and the angle of attack all lead to that pressure difference, along with a few other things like circulation, which is also caused by a sharp edge at the back of the wing. But everything kind of works together to generate that pressure difference and hence the lift that can combat gravity. It’s actually pretty hard to try and dumb it down without saying things that aren’t wrong.
This is fascinating, thank you. I understand that Bernoulli’s principle is involved, but it is not the sole nor even the most important factor in fixed-wing aircraft flight (if I’m using terms properly), and you’ve added some interesting context.
I give you my gratitude, and also my belief that you sound like an awesome sibling-of-a-parent to your nephew.
I recently taught my 11-year-old nephew “how planes fly.” A bit oversimplified, of course, but words like camber and lift and circulation were tossed around along with Bernoulli’s principle.
I’ve heard that Bernoulli’s principle is not that important for how planes fly.
Yes, there’s a bit of a myth around Bernoulli’s principle (faster moving fluids have lower pressure) and how much it matters for lift in plane wings. It came up in the conversation because I was trying to describe what air pressure is in general, and made an analogy to a pan flute (he plays flute in band).
Disclaimer: I’m an aerospace engineer, but I do not claim to be an expert on topic.
But for plane wings, the myth is really that the air above the wing moves faster because the curved surface is longer. That’s pretty much dead wrong, but is still in tons of textbooks. The air above the wing does move faster, but it’s because of a bunch of complicated physics that to be honest, I don’t really understand any more. I may have even been taught wrongly in college. But the result is that there is a velocity difference on a cambered wing even when it’s flat, and thus Bernoulli’s principle does apply, and there is a pressure difference giving you lift.
But that speed difference is mostly important at cruising altitude, when the wings aren’t angled, and it’s positively correlated with airspeed, so the thrust matters way more. When you’re climbing, the angle matters more. The camber (curvature) of the wing, the airspeed, and the angle of attack all lead to that pressure difference, along with a few other things like circulation, which is also caused by a sharp edge at the back of the wing. But everything kind of works together to generate that pressure difference and hence the lift that can combat gravity. It’s actually pretty hard to try and dumb it down without saying things that aren’t wrong.
I wish I had a cool family member like you when I was a kid! Thanks for being you. :)
This is fascinating, thank you. I understand that Bernoulli’s principle is involved, but it is not the sole nor even the most important factor in fixed-wing aircraft flight (if I’m using terms properly), and you’ve added some interesting context.
I give you my gratitude, and also my belief that you sound like an awesome sibling-of-a-parent to your nephew.
Ooh don’t fight THAT battle in front of your children
Yes, the truth is a battle, but only because people force it to be so.