Airflow across a wing
Cambridge UniversityCited 3× on HN, 2021–2025
demo · general · evergreen · 2021–2025 on HN
A one-minute clip from Cambridge's Prof. Holger Babinsky that debunks the equal transit time explanation of lift. It shows how air actually flows over a wing.
Linked in lift-theory arguments as a clear demonstration that air over the top of a wing does not need to catch up with air underneath.
Up next
11 mo on HNChildren Of The Magenta Line
Mossie Fly
11 HN recommender · 2021–2026
6 mo on HNThe Economics of Airline Class
Wendover Productions
6 HN recommender · 2017–2025
6 mo on HNDavid Fravor: UFOs, Aliens, Fighter Jets, and Aerospace Engineering | Lex Fridman Podcast #122
Lex Fridman
8 HN recommender · 2020–2022
6 mo on HNThe Fastest Way to Board a Plane Feels Like the Slowest
CGP Grey
9 HN recommender · 2020–2023
6 mo on HNZipline - How Rwanda Built A Drone Delivery Service
Real Engineering
9 HN recommender · 2019–2023
5 mo on HNPulling Power from the Sky: The Story of Makani [Feature Film]
X, The Moonshot Factory
6 HN recommender · 2020–2025
5 mo on HNJoe Rogan Experience #1361 - Cmdr. David Fravor & Jeremy Corbell
PowerfulJRE
5 HN recommender · 2019–2023
5 mo on HNBig Plane vs Little Plane (The Economics of Long-Haul Flights)
Wendover Productions
8 HN recommender · 2017–2023
5 mo on HNWhy You Should Put YOUR MASK On First (My Brain Without Oxygen) - Smarter Every Day 157
SmarterEveryDay
5 HN recommender · 2016–2025
5 mo on HNThe Boeing 787: Broken Dreams l Al Jazeera Investigations
Al Jazeera English
6 HN recommender · 2017–2024
4 mo on HNA NEW Trace! The FULL MH370 Story, so Far..
Mentour Pilot
5 HN recommender · 2024–2025
4 mo on HNHow to crash an airplane – Nickolas Means | The Lead Developer UK 2016
LeadDev
4 HN recommender · 2019–2024
3 comments from Hacker News
> right, the other is that if you remove every incorrect statement from the AI "explanation", the answer it would have given is "airplane wings generate lift because they are shaped to generate lift". ...only if you omit the parts where it talks about pressure differentials, caused by airspeed differences, create lift? Both of these points are true. You have to be motivated to ignore them. ▶ this video
Funnily enough, there's another web page on the NASA domain that outlines the "longer path" or "equal transit" theories as the correct cause of lift on an aircraft wing: link When I was studying for my PPL, they taught us using the equal transit theory, though the instructor couldn't help himself from telling us that it was a simplification. This video from Cambridge University illustrates what happens to the airflow over an aerofoil: ▶ this video
You're right- there isn't, and it doesn't. In fact a parcel of air moving over the top of the wing will beat its counterpart moving below it to the trailing edge. This[1] video has a very good demonstration of this. (Relevant part begins around 0:25.) So saying that air on top of the wing moves faster, creating a pressure differential and thus lift, is absolutely correct. The problem begins when some people try to come up with an intuitive explanation for _why_ the air would need to speed up. "Because this is the lowest energy state that conserves energy, momentum, and mass" isn't a very satisfying answer; neither is "because this system of PDEs say so"; so they came up with the "equal transit time" explanation, which is simple, intuitive, and completely wrong. Hopefully aeronautical engineers at P&W didn't actually believe that last bit? [1] ▶ this video