An In-depth explanation of the generation of lift

[pb_guy]

I ran across this in-depth explanation of how airplane wings develop lift. It is the first one that I have run across that finally, and fully, puts together the various components involved. One thing that he did not emphasize was that the upper layer actually gets to the TE of the wing before the bottom layer. And he does not talk about 'parasite' drag. Although this explanation does not help us to build a better wing, it does help us to understand why the darn things don't just fall out of the air, even if the wing is totally flat.

See: https://www.youtube.com/watch?v=CT5oMBN5W5M

ian

[lincoln]

Now you've done it!

[ilgk48]

Very appreciated!
P.

[Spiros]

Much appreciated. Thank you!

[OZPAF]

I don't want to be a spoil sport Ian, and thanks for taking the time to post this video. However, I'm more than wary of these fellows - especially when they label their videos as " How Airplane Wings REALLY Generate Lift" implying that how wings work has been a mystery!

Actually, the Fluid Mechanics basics of lift generation had been proposed by the late 19th Century by Joukowsky a leading Russian mathematician followed by the Prandtl - Lanchester theory of lift development - Prandtl a German and Lanchester in England coming to similar conclusions.

https://www.britannica.com/biography/Ludwig-Prandtl#ref59033

Prandtl developed the theory into his "Lifting line" method of calculating lift and it was widely in use by the mid 1920's in the design and development of aircraft.

This basic history is covered in Aerodynamics texts and thus I find these U Tube side show barkers insulting and annoying - willing to show and say anything to earn a dollar.

John

[Andrew D]

I think that he titled the video "REALLY" to (correctly) debunk what my Aerodynamics lecturer called the "Boy's Own" explanation of lift, ie the equal transit theory.  To many lift is a mystery, and anything that does offer a more credible non-mathematical explanation for the man on the Clapham omnibus has to be good IMHO. TBH I only skim watched the video, but I don't think he said anything particularly misleading. I did all of the theoretical stuff at uni, and TBH I barely understood it at all - few actually did, although I could spew it back in an exam (at the time!). John You are of course completely correct in everything you mentioned, but it is all mathematical, and at least the video gives a reasonable explanation in generally understandable language.  This is a ray of light amongst thousands of other click bait videos that try to convince folks that the earth is flat!

[Lastwoodsman]

Sun Feb 22 2026

Hello Ian:

     Thanks for the link.   A link is always better than no link .....

     In this discussion of  "lift",  let's go in full bore for the ordinary man,  typical of many others (Clapham obvious). 

      I have read,  that,  when a wing with positive incidence ( leading edge higher than trailing edge )  moves forward,  it  "deflects"  air downward,  causing the wing to lift.   The same principle applies to elevators and ailerons.

      I know this may be over simplified,  but it does explain how to get that sheet of plywood to fly ....   (pun intended) 

Lastwoodsman
Richard

[Prosper]

I believe that's right Richard. A moving surface with a positive angle of attack pushes air down, but the air isn't having any, and pushes back, thus keeping the surface airborne. Just ask any flying squirrel. But if that were the whole story, flat-plate flying surfaces would suffice for anything from a Bleriot to an Airbus A380. That's where one has to step down from the Clapham omnibus and invoke Kutta, Prandtl et al to see what's going on - accelerated local flow - stagnation points - circulation theory - all that stuff.

Stephen.

[Andrew D]

To be fair, the guy does explain about drag in his video, and why the flat plate isn't the best..

If you are designing the wing for an airliner, then sure study and understand the maths - you have to!  But if you are a young person trying to understand the world around you, or an older person who is just interested, then this isn't a bad video at all.  If just one 15 year old kid watches that video and thinks "that's interesting" and goes on to study Aerospace engineering - I'd see that as a win.  From experience I wish I'd have seen that at the age of 15, then I wouldn't have had my bubble completely burst by my Aerodynamics lecturer a few years later.

This isn't some sort of dumbing down, it's an appropriate approach to explain something at an appropriate level.  At O level or GCSE Chemistry they teach kids that atoms have neat shells like an onion where electrons exist orbiting the nucleus like planets  around a star.  Is that correct?  Hell no!  But it suffices to explain why for instance sodium and chlorine react to make salt.  For all intents and purposes, it is correct enough for that level of understanding...

So people have to go out and study Kutta, Prandtl et al to get a reasonable grasp on why an aeroplane flies?  Really?  As PB Guy said this video won't help you design a better wing, but it will reasonably explain why they don't fall out of the sky...

And before anyone asks, yes I am bored, not only bored but ill, propped upright on the sofa with a chest infection being jolly annoyed, looking for any excuse to have an argument!       

[Lastwoodsman]

Sun Feb 22 2026

     Yes there really are complicated components to lift and theory of flight.    My required text for Flight Theory 39 years ago,  was this book by  Wolfgang Langewiesche,  "Stick and Rudder"  1944,  which was pretty complicated ....

Pic #1     book by  Wolfgang Langewiesche  "Stick and Rudder"  1944

Pic #2     What's in Stick and Rudder:   The first bullet dot line says ....s
"The invisible secret of all heavier-than-air flight  -  the Angle of Attack.   What it is,  and why it can't be seen.   How lift is made,  and what the pilot has to do with it."

Pic #3     STICK AND RUDDER    BOOK  1944   HARD COVER

Yes,  the  invisible,  secret,  "Angle of Attack" ....  unless Wolfgang says otherwise.   Of course, there are differing opinions ...

Lastwoodsman
Richard

[steve-de24]

This is my 'go to' simplified aerodynamics book - and it has the advantage of being a free download (25MB) thanks to the FAA.
Aerodynamics for Naval Aviators

Steve

[OZPAF]

And before anyone asks, yes I am bored, not only bored but ill, propped upright on the sofa with a chest infection being jolly annoyed, looking for any excuse to have an argument!       

I hope Ian and I provided some light entertainment Andrew. Are you designing your next model?

By the way Stick and Rudder Richard is IMHO - one of the best books ever written on flying and together with one on gliding by Derek Piggot helped considerably when I took glider flying lessons.

John

[Jmk89]

I tend to start (and often finish) my aerodynamics research with Martin Simons, Model Airplane Aerodynamics.  There are 5 editions but any of them will get you well on the way to an understanding of the part of aerodynamics that deals with our 'planes.  Because he isn't dealing with higher speeds and weights of full-size aviation, the discussion can be much more focussed.

[OZPAF]

I tend to start (and often finish) my aerodynamics research with Martin Simons, Model Airplane Aerodynamics.

This is possibly the best way to start a better and more accurate understanding of the subject, and there is a free downloadable copy(early edition) available on the web.

https://dn790002.ca.archive.org/0/items/ModelAircraftAerodynamics/Model%20Aircraft%20Aerodynamics.pdf

John

[lincoln]

Sun Feb 22 2026

Hello Ian:

    Thanks for the link.  A link is always better than no link .....

    In this discussion of  "lift",  let's go in full bore for the ordinary man,  typical of many others (Clapham obvious). 

      I have read,  that,  when a wing with positive incidence ( leading edge higher than trailing edge )  moves forward,  it  "deflects"  air downward,  causing the wing to lift.  The same principle applies to elevators and ailerons.

      I know this may be over simplified,  but it does explain how to get that sheet of plywood to fly ....  (pun intended) 

Lastwoodsman
Richard

There is some truth in there, but the result of generating lift, by whatever method, would HAVE to be a deflection downward. The same would be true when flying a piece of plywood, at a positive angle of attack, through a cluster of ping pong balls* in a vacuum. It doesn't really tell you how it works. Furthermore, the leading edge doesn't have to be higher on some wing sections have some camber. As I recall, a Clark Y generates some lift at an angle of attack of 0. If you want zero lift, you need it at something like -2 or -3 degrees. https://flugbox.wordpress.com/wp-content/uploads/2015/04/lift-curve.png


*If you have enough sufficiently energetic ping pong balls, and a really, really, really large wing, maybe it will behave about like a real wing in air. However, I doubt it's possible to work at a sufficiently large scale.