How can you invoke a principle of conservation when energy is obviously exchanged between the wing leading edge and the air. After that everything according to the Great Bernoulli is circumstantial.
A more elaborate version of the Bernoulli equasion also takes a height difference into account. It goes like:
P1 + 1/2 * (ro)(v1)² + (ro) g (y1) = P2 + 1/2 * (ro)(v2)² + (ro) g (y2) with (ro) the density of the fluid and g = 9.80 m/s². y2 - y1 is the height difference. Torricelli was proven right by the above equation, but the one in the video wouldn't have been able to do that, for example.
The curved top of the wing in the production of lift is much over rated. A wing at zero angle of attack needs enormous speed to create usable lift. I read that a Cessna 210 would need to reach 400 mph to take off. Sounds reasonable to me. The theory of the cambered wing has been taught since the Wright Bros. and accepted and taught without question since then. I agree with you, the whole theory needs serious thought.
@winterka100 Tsk-Tsk-Tsk. You clearly have no clue. Ever heard of Flaps? Any idea what they do? They increase the camber, Lift & Drag; & decrease stall speed. Regardless, the 210 weighs 3800 lb max, uses a naca 64A215 airfoil at about 5 deg incidence. The clean airfoil (no flaps) produces a Cl ~0.7 at 5 deg. The wing area is 175 ft^2. Thus Vto = ~160 ft/sec or 110mph at sea level standard day conditions. At zero wing incidence, Vto = 220 mph which just so happens to be the 210's cruise speed.
@eyeammi Yes, I do have a clue, and I do know the function of flaps. Obviously you have no idea the difference between the angle of incidence and the angle of attack as shown by your misquoting of the specifications of the 210. I am only talking about the airfoil in it's simplest form as used in the worn out and blindly accepted theory of lift. Don't bother me with a bunch of impressive?? numbers without explaining what you think they mean.
What if spacetime flowed like a fluid between the earth and the moon? Would constriction & increased velocities occur? Could the bernouilli effect account for 'attraction' between masses in space? Could the bernouilli effect also account for the greater acceleration of lighter test masses in the Eotvos experiment?
@chatomare Yeah that's why pilots don't fly upside down for long periods of time. Most of those pilots who do cool tricks like going upside down only stay in that position for a few seconds.
@GeneralFalcao Planes can fly upside down all day long if they have the required fuel system (fuel tank, fuel injection,etc; also suitable engine lubrication system. It,s got nothing to do with the airfoil shape. Also zips on the pilot's pockets so that his money doesn't fall out.
Isn't it a bit interesting that the wing sections designed solely with reference to physics that predates the Wright brothers have been superseded by some rather odd shapes that work? The F117 Stealth fighter has nothing recognisable as a wing section! Also remember that the Wright brothers had to start from incorrect analysis and ended up with the good old fashioned cut and try method, with the whirling plate comparison method! I use the back of a steel comb for a good profile, nuthin subtle!
Cool video. At 1:45, did you mean P1+1/2(r)(v1)^2 = P2+1/2(r)(v2^2)? I must be getting old. I don't see a difference between the right and left hand side.
it's kinda hard to explain, but I get it though, so I'll give it a shot, Imagine a ballon with no air, what happens when you tryin to expand the balloon even with no air, you couldn't expand the balloon could you? because there is no air... because, air has has to occupy the space, so, the air has to go faster on the top because of the design of the airfoil..
Yeah yeah.. I know my explanation is kinda hard to understand, but I hope this helps..
NO. The air has absolutely no idea what distance it has, and the air above has no idea about the movement of air below. Air going faster simply because it has longer distance to go? Come on, that would be magic!
i will explain more clear When the upper side of wing hits the air it gives energy to the air to go faster. I am sure you saw many times when a car hits a man . The man rotates on car's hood then to windshield then above the car, then truck and then hits the ground
Well, it actually happened to me - that is, being hit by a car and flying over it. But I don't remember much of it, I just woke up behind the car. No youtube footage of this incident, though.
To the astonishment of the crowd, which surely hoped that I was dead, I was completely fine.
yes, thats why nascars have very low front bumpers so very little air goes beneath the car. They also have high rear bumpers so the little air that does manage to get underneath the car can very easily escape through the back. And when a nascar is going backwards at high speeds more air gathers underneath the car, the air compresses and pushes up on the car
Although air flows faster over the wing, it has nothing to do with a "longer path". In fact, in an average light plane, the top of the wing is only 1.6% longer than the bottom. To satisfy the "longer path" theory a small cessna would have to fly at around 300kts.
Fact is, the flow is so much faster on the top that it reaches the trailling edge much earlier than the flow on the lower part. The air speeds up because of the lower pressure on top and not the other way around.
The speed difference between the air on top of the airfoil. Dynamic air pressure is a function of velocity. Since the air stay together, the air on the top is moving faster, therefore has a lower pressure.
I'm not sure about that. Bernoulli's principle assumes an incompressible fluid. You are referring to a change in density here which isn't part of the equation.
In many situations the changes in pressure and temperature are sufficiently small that the changes in density are negligible. In this case the flow can be modeled as an incompressible flow. Otherwise the more general compressible flow equations must be used.
Symmetrical wings produces lift only if the attack angle is positive, otherwise, if the angle of attack (let's say the angle between the chord of the wing and the flow velocity) is 0 there is no lift.
Thanks. I may had focused on Bernoulli but it is NOT the ONLY factor for the lift. NASA had an article on this, addressing the issue on Bernoulli's Principle vs Newton's Third Law of Motion. It says that both are important factors. :)
@slick1120 also the navier-stokes equation plays a high role. but it's not true, that the shape is responsible for the lift, the angle of attack is responsible for that.
@slick1120 The P1 & P2 mistake is noticeable right away for anyone who knows about it but what I am interested is the Newton's Third Law of Motion playing a role in lift, all discussions always have Bernoulli's Principle dominating, would be able to make a video explaining the NASA article.
I hate when people give that stupid explanation of how planes fly. The air travels faster over the top then the the bottom, complete horse shit.I don't believe thats why it creates lift.
the wing deflects air downwards, which causes the air pressure to rise (air has mass and it cant get out of the way fast enough , so it compresses = higher psi). The top side of the wing creates low pressure b/c as it travels through the air it creates a "VOID". Which air has to fill,so the pressure is lower.
Explain to me then how it is that when you blow over the surface of a piece of A4 paper, the paper starts to come up? It has no way to deflect air down.
In the case of symmetrical airfoils it's the angle of attack that makes the air move faster over than under the wing. Without an angle of attack the air will move at the same speed on both sides and the wing will not generate lift. Unless it starts moving downward and an angle is made between the wing and the airflow.
I am not a scientist, just a student pilot. I am going to ask my teacher more information about this, but i am pretty sure it works in the way I explained.
An airfoil "fly" beacuse it has a shape that divert the airstream down, toward the ground. in other words it generate lift thanks to Newton's third law of motion: the wing divert air down and air produces a reaction that push the wing up. It is a common mistake to think a plane fly thanks to bernoulli's law.
(I study aerospace engineering, you can trust me! ^^)
Sorry, but the fact that an airfoil generate lift thanks to bernoulli's principle is totally untrue. To create enough difference in velocity between the two sides of the airfoil the upper side of the airfoil should be incredibly curved and thick, making the airfoil completely unable to fly for the immense drag it generates.
An airfoil "fly" beacuse it has a shape that divert the airstream down, toward the ground: in other words it generate lift thanks to Newton's third law of motion
im confused
crp1000 3 days ago
wait wait wait isnt the intro music from aperture science?
LiewDarWin 1 month ago
How can you invoke a principle of conservation when energy is obviously exchanged between the wing leading edge and the air. After that everything according to the Great Bernoulli is circumstantial.
g1geo1g 2 months ago
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karishmaprasad 2 months ago
um get it right THIS IS BOYLE'S PRINCIPLE!!!!!!!!!!
thebubbac11 2 months ago
can i have the voice over. lecture of this video? right now? reply me.. thank you
huuhhhuuuhuhuh 5 months ago
Thank you for this vid! As an engineering student, i find this so helpful! Very well explained and great examples of application.
dragonfirelee 6 months ago
A more elaborate version of the Bernoulli equasion also takes a height difference into account. It goes like:
P1 + 1/2 * (ro)(v1)² + (ro) g (y1) = P2 + 1/2 * (ro)(v2)² + (ro) g (y2) with (ro) the density of the fluid and g = 9.80 m/s². y2 - y1 is the height difference. Torricelli was proven right by the above equation, but the one in the video wouldn't have been able to do that, for example.
Just sayin'
FabFubar 6 months ago
This worn out theory of lift consists mainly of hot air.
winterka100 6 months ago
The curved top of the wing in the production of lift is much over rated. A wing at zero angle of attack needs enormous speed to create usable lift. I read that a Cessna 210 would need to reach 400 mph to take off. Sounds reasonable to me. The theory of the cambered wing has been taught since the Wright Bros. and accepted and taught without question since then. I agree with you, the whole theory needs serious thought.
winterka100 6 months ago
@winterka100 Tsk-Tsk-Tsk. You clearly have no clue. Ever heard of Flaps? Any idea what they do? They increase the camber, Lift & Drag; & decrease stall speed. Regardless, the 210 weighs 3800 lb max, uses a naca 64A215 airfoil at about 5 deg incidence. The clean airfoil (no flaps) produces a Cl ~0.7 at 5 deg. The wing area is 175 ft^2. Thus Vto = ~160 ft/sec or 110mph at sea level standard day conditions. At zero wing incidence, Vto = 220 mph which just so happens to be the 210's cruise speed.
eyeammi 5 months ago
@eyeammi Yes, I do have a clue, and I do know the function of flaps. Obviously you have no idea the difference between the angle of incidence and the angle of attack as shown by your misquoting of the specifications of the 210. I am only talking about the airfoil in it's simplest form as used in the worn out and blindly accepted theory of lift. Don't bother me with a bunch of impressive?? numbers without explaining what you think they mean.
winterka100 5 months ago
What if spacetime flowed like a fluid between the earth and the moon? Would constriction & increased velocities occur? Could the bernouilli effect account for 'attraction' between masses in space? Could the bernouilli effect also account for the greater acceleration of lighter test masses in the Eotvos experiment?
JustinSepheren 7 months ago
slick info!
meterdatamanagement 8 months ago
not quite, how ten planes can also fly upside down....according to what you say, when planes are upside down they would crahs down to the ground...?
chatomare 9 months ago
@chatomare Yeah that's why pilots don't fly upside down for long periods of time. Most of those pilots who do cool tricks like going upside down only stay in that position for a few seconds.
GeneralFalcao 8 months ago
@GeneralFalcao Uh, wrong. Aerobatic planes have symmetric wings - they generate as much lift upside down as right side up.
csmcmillion 7 months ago
@GeneralFalcao Planes can fly upside down all day long if they have the required fuel system (fuel tank, fuel injection,etc; also suitable engine lubrication system. It,s got nothing to do with the airfoil shape. Also zips on the pilot's pockets so that his money doesn't fall out.
winterka100 6 months ago
Isn't it a bit interesting that the wing sections designed solely with reference to physics that predates the Wright brothers have been superseded by some rather odd shapes that work? The F117 Stealth fighter has nothing recognisable as a wing section! Also remember that the Wright brothers had to start from incorrect analysis and ended up with the good old fashioned cut and try method, with the whirling plate comparison method! I use the back of a steel comb for a good profile, nuthin subtle!
SuperAviatar 11 months ago
your equation is wrong, the second half should be P2 and V2 not P1 and V1 again
12powerhouse12 11 months ago
@12powerhouse12 yep. i know. just a typo error.
slick1120 11 months ago
@12powerhouse12 yep i know. typo error
slick1120 11 months ago
@12powerhouse12
First of all, great video! Very informative. You should correct your formula either in the description of whatever means you've got.
kyiss 9 months ago
interesting! so much stuff to learn..I like!
7argool 1 year ago
the truth is than that the upper air has more space to fill
cris23dumi 1 year ago
great vid thanks!!!!!
mmeeeeooww 1 year ago
Cool video. At 1:45, did you mean P1+1/2(r)(v1)^2 = P2+1/2(r)(v2^2)? I must be getting old. I don't see a difference between the right and left hand side.
Ripley747 1 year ago 2
@Ripley747 i saw that too, the correct bernouli equantion is what you said.
But, good video tanks.
DelegadoNINJA 1 year ago
Sweet !
captfalconXX 1 year ago
Search for "incorrect lift theory" with Google and open the NASA link.
Read and learn!
MachWaveRider 1 year ago
Comment removed
MachWaveRider 1 year ago
Lift does not develop as shown in this video. The "equal transit time" or "longer path" explanation is nonsense. And this is a certainty!
If this theory was correct aircraft would not be able to fly upside down.
MachWaveRider 1 year ago 2
Thanks a lot I'm only in 6th grade but this is my project!! :)
freeflyer0123 1 year ago
This has been flagged as spam show
ship ! i can hardly understand the equation ... help pls ...
danezelcruz23 1 year ago
ship ! i can hardly inderstand the equation ... help pls ...
danezelcruz23 1 year ago
dont get it
rjkhemlani1996 1 year ago
Thanks a lot for the video. Studied Bernoulli's principle in the school, and now after many years while doing PhD.
Vaibik 1 year ago
Nice
EarthquakeMachine 1 year ago
hey you showed the equation
P1+1/2R(rho)v1^2= P1+1/2R(rho)v1^2
but tht is obvious
but eqn should be
P1+1/2R(rho)v1^2= P2+1/2R(rho)v2^2
aman2arora 2 years ago 5
Comment removed
avalosalvear 2 years ago
This is oversimplification. It's not the shape that matters the most, it's the angle of attack.
How the heck would you explain flying upside down?
Azarien 2 years ago 2
nice job. Thanks.
b24688 2 years ago 2
thanks was really helpful!
niftynishi27 2 years ago
hokay! so hereys de bernoulli's principle! dude way helpful thanks!!! it took a while for me to get this
omygoshdang 2 years ago
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Lathander28 2 years ago
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identernet 2 years ago
it's kinda hard to explain, but I get it though, so I'll give it a shot, Imagine a ballon with no air, what happens when you tryin to expand the balloon even with no air, you couldn't expand the balloon could you? because there is no air... because, air has has to occupy the space, so, the air has to go faster on the top because of the design of the airfoil..
Yeah yeah.. I know my explanation is kinda hard to understand, but I hope this helps..
WillStriveHarder 2 years ago
Because, the air has a greater distance over the top so it has to go faster than the air on the bottom
elik1985 2 years ago
NO. The air has absolutely no idea what distance it has, and the air above has no idea about the movement of air below. Air going faster simply because it has longer distance to go? Come on, that would be magic!
Azarien 2 years ago
i know it is hard to imagine
i will explain more clear When the upper side of wing hits the air it gives energy to the air to go faster. I am sure you saw many times when a car hits a man . The man rotates on car's hood then to windshield then above the car, then truck and then hits the ground
elik1985 2 years ago
Well, it actually happened to me - that is, being hit by a car and flying over it. But I don't remember much of it, I just woke up behind the car. No youtube footage of this incident, though.
To the astonishment of the crowd, which surely hoped that I was dead, I was completely fine.
Azarien 2 years ago 9
this is the same principle that causes balls the curve. In soccer or baseball you want a strong sideways rotation to curve the ball
tennisIS4pussys 2 years ago
thanks so much! very helpful ! :)
vt1875 2 years ago
great explanation!im malaysian student
fzul12 2 years ago
Is this the same theory that explains why nascars blowover when they go backwards?
spasticchuckles016 2 years ago
yes, thats why nascars have very low front bumpers so very little air goes beneath the car. They also have high rear bumpers so the little air that does manage to get underneath the car can very easily escape through the back. And when a nascar is going backwards at high speeds more air gathers underneath the car, the air compresses and pushes up on the car
tennisIS4pussys 2 years ago
thx
spasticchuckles016 2 years ago
Although air flows faster over the wing, it has nothing to do with a "longer path". In fact, in an average light plane, the top of the wing is only 1.6% longer than the bottom. To satisfy the "longer path" theory a small cessna would have to fly at around 300kts.
Fact is, the flow is so much faster on the top that it reaches the trailling edge much earlier than the flow on the lower part. The air speeds up because of the lower pressure on top and not the other way around.
bruno84 2 years ago
nice explanation bro
thinkmanworld 2 years ago
Totally agree.
aper2009 2 years ago
What causes the lower pressure on top?
bench175 2 years ago
The speed difference between the air on top of the airfoil. Dynamic air pressure is a function of velocity. Since the air stay together, the air on the top is moving faster, therefore has a lower pressure.
KlausvonAusburg 2 years ago
@bench175 air travels faster over top, so Velocity is higher.
So when velocity increases pressure decreases.
Indianmalujl 2 years ago
Bravo sir! Bravo. I finally get it.
dawance88 2 years ago 2
Are we talking about dynamic or static pressures here?
SteveTheCart 2 years ago
Why has the moving air got less pressure? What has it got less pressure than? What is the motion measured relative to?
SteveTheCart 2 years ago
its got less pressure because its got a higher velocity. the faster it goes, the further the particles spread out therefore less pressure.
sticky9cd 2 years ago
I'm not sure about that. Bernoulli's principle assumes an incompressible fluid. You are referring to a change in density here which isn't part of the equation.
SteveTheCart 2 years ago
In many situations the changes in pressure and temperature are sufficiently small that the changes in density are negligible. In this case the flow can be modeled as an incompressible flow. Otherwise the more general compressible flow equations must be used.
sticky9cd 2 years ago
Un Video Excelente muy bien explicado (An & Arth)
binover2 2 years ago
Comment removed
HomoBorealis 2 years ago
This comment has received too many negative votes show
This is totally wrong. It has nothing to do with Bernoulli's Princilpe and is only BS.
HomoBorealis 2 years ago
great video
snickle13 2 years ago
it seems believable that newton's third law creates an aircraft lift, and not bernoulli. then how come symmetrical wings produce lift?? answer that
addieroxrev09 2 years ago
Symmetrical wings produces lift only if the attack angle is positive, otherwise, if the angle of attack (let's say the angle between the chord of the wing and the flow velocity) is 0 there is no lift.
matteolegna 2 years ago 3
oh i see. thanks for the info.
addieroxrev09 2 years ago
im a race car driver, pilot and i spray those things all day long, wow bernoulli you're awesome!!!!!
stormthorgerson 2 years ago 4
Comment removed
stormthorgerson 2 years ago
increase in velocity means a decrease in pressure....
addieroxrev09 2 years ago
im about to enter an aviation school! I must watch this times and times again hahaha
Redirah 2 years ago
Thanks. I may had focused on Bernoulli but it is NOT the ONLY factor for the lift. NASA had an article on this, addressing the issue on Bernoulli's Principle vs Newton's Third Law of Motion. It says that both are important factors. :)
slick1120 2 years ago 3
@slick1120 also the navier-stokes equation plays a high role. but it's not true, that the shape is responsible for the lift, the angle of attack is responsible for that.
ms101289 1 year ago
@slick1120 The P1 & P2 mistake is noticeable right away for anyone who knows about it but what I am interested is the Newton's Third Law of Motion playing a role in lift, all discussions always have Bernoulli's Principle dominating, would be able to make a video explaining the NASA article.
Verdelufe 8 months ago
Cool! Applies to my Mustang!
Les
bigblockmustang 3 years ago
it's pronounced [bernui] not [bernuli]..
Lordkire 3 years ago
I thought Bernoulli was born in Holland...
Dutchdrummer99 3 years ago
he was (born in dutch province: Groningen), but he lived in switzerland.
MoopyToopy 3 years ago
I hate when people give that stupid explanation of how planes fly. The air travels faster over the top then the the bottom, complete horse shit.I don't believe thats why it creates lift.
the wing deflects air downwards, which causes the air pressure to rise (air has mass and it cant get out of the way fast enough , so it compresses = higher psi). The top side of the wing creates low pressure b/c as it travels through the air it creates a "VOID". Which air has to fill,so the pressure is lower.
treborly 3 years ago
Explain to me then how it is that when you blow over the surface of a piece of A4 paper, the paper starts to come up? It has no way to deflect air down.
Meuk1982 3 years ago
bernouli does have an effect on lift, but it consists of probly like less than 2% of the lift generated.
when u blow on the paper, that is bernoulli. I didnt say it did not exists, just not a major factor in flight.
treborly 3 years ago
untrue, tests in wind tunnels have sown that 70% of the lift is caused by Bernoulli's principle, and only 30% by the effect you explained.
Lordkire 3 years ago
maybe when the angle of attack is extremely low and the shape is suited to demonstrate Bernoulli principle.
some airfoils are symmetrical, why would air travel faster over top than below?
I`ve been testing this kinda stuff since i was like 5 years old. I`d trust my experience over someones "schooling" any day.
treborly 3 years ago
In the case of symmetrical airfoils it's the angle of attack that makes the air move faster over than under the wing. Without an angle of attack the air will move at the same speed on both sides and the wing will not generate lift. Unless it starts moving downward and an angle is made between the wing and the airflow.
I am not a scientist, just a student pilot. I am going to ask my teacher more information about this, but i am pretty sure it works in the way I explained.
Lordkire 3 years ago
An airfoil "fly" beacuse it has a shape that divert the airstream down, toward the ground. in other words it generate lift thanks to Newton's third law of motion: the wing divert air down and air produces a reaction that push the wing up. It is a common mistake to think a plane fly thanks to bernoulli's law.
(I study aerospace engineering, you can trust me! ^^)
johnnyblade86 3 years ago
I learned both in flight school. Bernoulli and Newtons third law
Meuk1982 3 years ago
Sorry, but the fact that an airfoil generate lift thanks to bernoulli's principle is totally untrue. To create enough difference in velocity between the two sides of the airfoil the upper side of the airfoil should be incredibly curved and thick, making the airfoil completely unable to fly for the immense drag it generates.
An airfoil "fly" beacuse it has a shape that divert the airstream down, toward the ground: in other words it generate lift thanks to Newton's third law of motion
johnnyblade86 3 years ago
thanks!!
it really helps!!
duncanma0128 3 years ago
Glad to help. :)
slick1120 3 years ago
@slick1120 Does is rational number principle that was solved by the 16 year old kid applied to physical space?
WhoisJacqueFresco 1 year ago
Great Video!
pixzers 3 years ago