What makes an airplane fly? (Bernoulli vs. Newton)

I'm Brodie Brazil, Commercial Pilot & Certified Flight Instructor.

On this channel, I'll share the best tips & tricks for learning how to become a better pilot.

IN THIS VIDEO: What makes an airplane fly... besides MONEY... and which theory of lift really makes the most sense: Bernoulli's Principle, or Newton's Third Law?

** I am a licensed FAA Flight Instructor, but in this video, not acting as YOUR flight instructor. None of the content presented here should supersede your ACTUAL flight training. **

#aviation #flying #pilot

[FdlF]

This is probably the worst explanation of lift I've seen in the entire Youtube 👍

[ap]

Thank you so much for opening up another way of thinking about how those damn things lift off the ground. It is much appreciated. This new channel really rocks. Keep on with this...please.

[lorenzopilotto]

Hi Brodie, with all due respect, the explanation is wrong in so many ways.

The equal transit time theory is just wrong, as there isn't any physics principle to back that theory, in fact, if you look videos of an airfoil in a wind tunnel, the opposite thing happens.

Why does air accelerate and stick to the wing? Thats because of Coanda's effect, air is attached to the upper most curved surface of the wing, creating a depression where air is sucked in and accelerated (Bernoulli)

Then you have downwash contribuiting to lift, explained with Newton's Third Law.

Hope It is elaborated enough, anyone correct me if I am wrong.

Safe flying!

[kabzebrowski]

I don't want to sound mean nor anything, but that's an incorrect explanation. If pushing air down was the sole reason for lift then it would be impossible for planes to fly upside down - something we know isn't the case. The catch is that Bernoulli and Newton are two sides of the same coin, there is no "vs". Bernoulli's equation comes directly from applying some conditions on Newton's three laws. They do not compete.
You can check NASA's explanation on lift on their website, it's a good read, and I'd also reccomend watching 'lift: no curves required', by Light and Sporty Guy, here on youtube, a very good video on lift, foils, and he also provides the derivation of Bernoulli's equation from Newton's laws.

[dracomoth]

The only thing that I don't understand is, Newton's third law establishes that for every force there is an equal reaction force but in opposite direction. On vectors this basically means that the sign of the vector changes. I understand this means that for every Force A (per your diagram) pointing left, the reaction force is pointing right, not down. I think the correct explanation is in the green lines of your diagram. Air is coming from right to left flat, but as it encounters the wing profile (with the angle of attack) it makes the air go down (both in the upper surface and the lower surface, as you have drawn in green lines). This generates a reaction force upwards, which is the lift. If I'm not mistaken of course.

[squawkdude]

Lower pressure above the wing is due to the Venturi effect. Downwash created by the wing also provides lift. That's how I understand.

[acecabral]

Hey Brodie!

Solid video as always. I would quote the book Stick & Rudder, “an airplane flys due to the Incline plane of the wing and pushing down the on coming air”. I mean, why do they call it an airplane.

It’s all in the incline plane of the wing. According to the author, Bernoulli’s theory, laminar flow, circular theory are all engineers concepts trying to explain the simple concept of above statement.

[richardarchbold]

Hi, Brodie: Just want to let you know that I am really enjoying this series. Back in the day, I had thought seriously about being a recreational pilot but after a couple of lessons, decided that the time required (and expense) made that impractical as I was concentrating on career, family, etc. Your clear presentations remind me of what I was intrigued by. Thanks!

[workablob]

My brother and I fly, and he thinks I'm crazy when I mention Newton's 3rd law. I came upon it on my own by comparing it to skiing on the water. Instead of water it is another fluid being air. I think it's cool that you confirmed my theory.

[jamesnel]

My mate I believe you are much closer than any of the previous videos I've watched. Everyone is concerned about Bernolli's principle. Although there is nothing rong with wat he said that is not what creates the lift needed for a plane to take off.

[juncearyoutube]

Ive been discussing this issue for years. I have no involvement with airplanes, I do have a very deep technical knowledge about gas turbines. I think, one of the reasons this is an argument with an airplane wing is because while flying, a wing doesn’t really need to create much lift, it could generate a lot more, but what you want is a compromise between lift/low forward air resistance. In the turbine of a gas turbine, you want maximum “lift”, you wan to extract as much energy from the fluid (hot gasses coming from the combustion chamber at high pressure and speed) as possible, and thats why a turbine blade has a much more crooked shape, ultimately what you want is to redirect the flow downwards to create an upwards momentum on each blade that forces the turbine rotor to turn. For me in a gas turbine is a lot clearer that is Newton’s third law the most important contributor to “lift”

[keithstirling]

Thanks. I think you're onto something

[Mach]

the action - reaction description given here is completely wrong.