It's because this is dumbed down for elementary school show and tell. Vectors and forces are simplistic but many ignoramuses in society couldn't stay awake for 5 minutes.
Careful not to confuse lift due to the shape of the wing (which I believe is what you are trying to demonstrate) and lift simply due to angle of attack. You'll notice that if you create a flat wing, maybe just a cut of ply wood, you will still achieve lift with the high angle of attack you are using. This has nothing to do with Bernoulli, just force balance. You can do the same thing sticking your hand out the window of a car and adjusting the angle of attack.
I read a respond in the Smithsonian magazine years ago from someone who said he was a former air force pilot. He said you could make a barn door fly if you applied enough power to it and had a sharp enough angle of attack.
Exactly, angle btw flow of air and plane of wing is large , here upward force is exerted because of one component of momentum of air not because Bernoulli's , there will be large horizontal force on wing too and that opposes forward motion of plane.
@@freshapple920 in reality, a partial vacuum is created with very less air molecules spread on top of wing, whereas under the wing in less area, many Air molecules get accumulated. Both are given a downwash, but due to vacuum above ,the molecules on top, are going back and try to stick to surface where a vacuum is created(coanda effect) but can't, and do a downwash. Now there's a pressure difference on top of wing and below the wing , and this pressure difference makes air above move faster and hence generates a lift. Please see if this answer is correct.
Good look getting this education in American schools. It’s turn to page 307 and read and take your test after............Ms.frizzle was the best teacher ever.
Its actually because the air at the bottom has more contact with the bottom of the wing than the top due to the wing's curved design, and also because of the wing's tilt upwards, the air applies more force at the bottom than the top.
Need to have no angle between the bottom of the wing and relative wind, (air compresses, the wings at an angle therefore air hitting the bottom of the wing....), to prove bernoulli.
Great video! I would be careful with citing Bernoulli in this situation. Bernoulli can really only be applied along a single streamline, and thus it can not be directly applied when discussing airfoils. The velocity to pressure relationship is not as direct as implied by Bernoulli.
My proof that i managed to find the 1st comment before the idiots (ppl that are going to write repetitive jokes about youtube and recommendations) arrived.
I'm not so sure it's higher pressure on top that caused the lift as it is the fact the wing was shaped to capture the air and push it down which caused the lift.
@Matt Parker, where di you buy the little wing you had at the beginning? If you made it, is there any plans online to build one? I am just looking for the dimensions and scale, thank you
👉🏻👉🏻 The principle is that “Velocity increases and pressure decreases” As the airflow increases on top on the blob pressure decreases it creates vacuum and air pressure beneath the blob rises instantaneous to fill in the void so it lifts up, so does the wing of a plane, etc.
*In fluid dynamics, Bernoulli's principle states that an increase in the speed of a fluid occurs simultaneously with a decrease in static pressure or a decrease in the fluid's potential energy. The principle is named after Daniel Bernoulli who published it in his book Hydrodynamica in 1738. From wikipedia*
The wing generates lift not because the air flows faster at the top, this faster flow at the top just make it generate more lift. If that was the reason lift was created, a flat wing would never work, and it works .
Physics or Aerodynamics is not my major but I got very fascinated about it in my secondary school(high school) and read about it. Whenever I use superman, man of steel to help people visualize a sonic boom, they take it as a joke lol and that was before I saw videos of jets breaking sound barriers with ease lmao
Physics teacher now : “ok class, i give you a question about how much time needed for a flying elephant to go to Africa from America but the elephant was made in China. Give me your answer before 10 o clock.” Ten minutes ago before 10 o clock.
At 1:14 he says it exactly backwards. You get higher *velocity* over the top of the airfoil, not higher *pressure*. As velocity increases, pressure decreases. The lower velocity below the airfoil results in higher pressure which produces lift
@@gjohn163 On a cambered airfoil, such as an airplane wing, turbine blade, etc. let’s say the leading edge is point A and the trailing edge is point B. Due to the camber the distance traveled along the upper surface is longer than that of the lower surface. So the molecules on the top of the wing have to travel faster to get from point A to point B, and the molecules on the underside of the wing travel slower to get from point A to point B
Yeah I can imagine that, but surely the pressure difference from the velocity difference on either side of the airfoil is small and won't generate any lift... I might be wrong though
@@gjohn163 Its basic aerodynamics. I am an aeronautical engineer. Trust me, its this concept that makes jet engines generate thrust and airplanes fly. Even though I understand the concepts it’s still hard for me to believe how it works. That’s why I have been fascinated with flight ever since I was a little kid and chose that as my profession
Oh okay... I saw somewhere that it wasn't necessarily speed differences but more to do with circulation generated from the incoming velocity vector field... I'm trying to figure out where it all fits...
Is there a place to purchase that airplane-on-a-stick demo? Or instructions on how to make something similar? I'd love to use that as a demonstration with my little kids without having to remove masks to blow over the top of a piece of paper.
A question for you geeks. About nails and aerodynamics, not the one on fingers or toes but the one carpenters use. The question goes as follow: What direction will a nail fall if you trow it say, from the Eiffel tower, will the hammer head be down, or will the pointy tip be down?
That's... a very good question. The center of gravity it closer to the hammer head, but where is the center of pressure?... Actually I'm not sure if there's any stable orientation 🤔
I thought Sir George Cayley in about 1850 demonstrated how a wing would creat lift. He even made the first heavier than air flying machine. Unfortunately there was no efficient engines to power it. We had to wait for the Germans to invent the internal combustion engine some years later.
I don’t understand why it’s the negative pressure on top of the wing that gives it lift? It looks like the angle of the wing pointing up gives it its lift?
Interestingly, In wind tunnels air clearly goes faster on top of the wing but experimental evidence actually shows that in real life with a moving wing in still air, a parcel of air under the wing will reach the trailing edge first. The problem people get confused with Bernoulli’s principle is cause and effect. Fast air doesn’t create lower pressure on the wing. It’s actually the wing that causes lower pressure. It is this Pressure Gradient Force (PGF) which causes air to accelerate, as it has mass and nothing will move without a force. Where does this low pressure come from? Likely due to the fact that an angle of attack causes the top of the wing to be deflected away from the oncoming flow, but due to air’s pressure and low viscosity it will adhere to the wing’s surface. Air curves around the top of it, meaning that there must be a force causing it to take a curved path instead of move in a straight line. That is also caused by the pressure gradient force.
That shows angle of attack much more than aerofoil effects. Bad explanations meant I never properly understood aerofoil lift until i was an adult and looked it up myself.
Start with a window size box fan. Make a shroud out of stiff cardboard that fits over the fan and tapers to about 1 ft square. Extend that section for about a foot. Make a flow straightener out of more cardboard that interlaces into a grid with 1 in square openings about 4 in long. Glue to the square opening. Set up some supports so the thing does not fall over or move. This can be built in a morning with cardboard and a hot glue gun. Turn on the fan. The three speeds will give you some variation on airflow velocity. Have fun.
It's just the demonstration of Newton's 3rd law: Action = -Reaction. That same would have happen anything that obstruct that incoming wind. If he was trying to show how lift is generated over a wing, the explanation is not at all enough or covered.
This is exactly what we did at physics lab at school. We couldn't build the model correctly hence didn't performed the against the wind. Anyway our team was smart enough to angle the wing so a force is build upwards, but it was not Bernoullie at all 😁. As the teacher was not paying much attention, we got marks 😂.
At the moment 94 thumbs down actually know that the lift was achieved with angle of attack in that demonstration, and 3k thumbs up are once again fooled into the outdated theory of flight that Bernoulli’s Principle is the only lifting force acting on a wing.
Think of it as a race track going around a corner. A person running on the outer lane has to go faster to keep up with the person in the inner lane. If you have 5 people in the outer lane and 5 people in the inner lane running at the same speed in the straight stretch and only when the curve begins does a runner start going faster, each time a runner starts going faster they will separate from the others in their lane. That separation is a simulation of the drop in pressure over the top of the wing.
There has been an argument for years as to what causes lift. Angle of attack or shape of wing. Although not great I have flown rc aircraft with different airfoil. A flat bottom with an increase in speed will gain altitude. Flying inverted is hard, a lot of down elevator required. A semi symmetrical airfoil will do the same, just not as fast. But flying inverted is easier. A symmetrical airfoil will not increase altitude with speed. Flying inverted ther was little to no change in trim to maintain level flight. In all cases a change in angle of attack effects the attitude of the aircraft at a given speed.
Good observation. Flat bottom airfoil has positive camber to it and will generate lift even with zero angle of attack which means that when you fly inverted you need to first use elevators to negate the lift created by the now flat top wing and then more elevator use to create angle of attack over the wing that will create lift to carry the aircraft. Symmetrical airfoil is essentialy the same as flat plate wing and it won't generate any lift at zero AoA. But as you said the inverted flight is then easier.
Nice demo for AoA, but not Bernoulli's effect. You can have a symmetrical wing and still gain lift if sufficient AoA is there. Bernoulli's play a very small role than AoA.
