Nice video. I in particular liked the part when the LED was turned on too early and the bird saw a white "wall" and tried to land on it. This was not (of course) involved in the original paper and I appreciate this footage. I'd like to point out 3 things on the video, though: (1) The wingtip vortices do not "helps provide lift". They are unavoidable byproduct of producing lift with a finite span wing, and they actually cause the induced drag. (2) It's not the lift but the *lift coefficient* that is distributed more evenly over the body (spanwise). Please see the red lines in figure 5 of the paper. This is the whole point of the paper... (3) The video acknowledges 2 professors but not the 2 postdocs who played the major roles in the experiments and analysis. No mentioning on the LaVision (equipment company) people either, who not only provided the software/hardware but actively involved in the experiments.
Note how the vortices were not on the wingtip, but inboard. This is why birds don't need vertical stabilizers. Prandtl figured out how to reduce induced drag even more than his elliptical lift distribution, but it was practically ignored for 80-90 years. Look up NASA Armstrong Flight Research Center's flying wing called the Prandtl for more info.
Also, lift increases drag so I don't know what they meant by "decreasing drag." The least amount of drag would be the tail pointing straight back, parallel with the airflow.
@@nelsonphillips the bottom surface of the wing pushes air down, while the air above the wing rushes to fill the low pressure hole that the wing just pushed into the air. And if the wing is an aerofoil shape, it will add more lift that way. It's just the same as a propeller or fan. Does it work by pushing air in front of it, or sucking air? And if you say by sucking air, how come a non aerofoil blade or wing can still work? Lol To put it another way, if you stick your hand out the window while driving down the road, do you feel more pressure on the front, or suction on the back?
When I was doing my PPL the tailplane was used to change the pitch of a/c by using the elevators to increase or decrease the amount of lift it produced. The video seems to be somewhat underinformed.
There was one other thing that they got wrong. Aircraft wings do provide lift! That is how an aircraft can be pitched up or down. By increasing the lift in the elevator the nose is pitched down.
Not necessarily. It depends where they are in relationship to nearby flying surfaces. Wingtip sails on gliders and airliners reduce drag by interacting with the wingtip trailing vortices.
Yes, I think the narrator's statement on 0:58 is incorrect ('as expected the researchers saw vortices spinning down from the wingtips, this helps provide lift..."). I was taught that ground effect glide on final on a glider is achieved by maximizing lift through compression of the air underneath the wing against the ground and REDUCTION of drag by partial elimination of wingtip vortices. A bigger vortex implies bigger drag as the wing passes through the air. It doesn't create lift.
I think who wrote the script had in mind the circulation theorem. The pair of vortices that is the signature of induced drag is really the same vortex that produces the lift. Thus, the narrator is not really wrong when she said "this helps provide lift". But it's kinda confusing to people who know practical aerodynamics but not the theory. But let's be honest, they've tried their best, the internet will always be smarter than the small team in the production!
@@FullAfterburner so, I'm starting te new differential equations course and fluid dynamics this semester, hope will go well.I'm gonna try to do projects like yours, have a great day.
I love how this video describes an aircraft elevator's purpose in stabilizing flight and makes it sound like a new discovery when even the very first aircraft had it 😂 The goes on to suggest wingtip vortices create lift when in fact lift creates vortices which aircraft designers want to minimize.
The bird is producing a momentary "down elevator" control exactly when passing the bubbles @0:59 and that's why there is a second vortex pair formed. The bird "knows" exactly to keep it's tail "idle" and not creating any lift as the main wings are much more efficient at creating lift than the tail - this knowledge is shared with most aircraft designers. What the Owl does and no plane can do, is to use the tail as flaps, to supplement lift at slow flight and this is because it can move the wings to control and balance the centre of pressure in relation to centre of gravity. Tail providing lift is a way to make any flight inefficient as it increases the energy spent in air vortex, but at slow speed the Owl needs as much lift as possible, and it's a good way to slow down before landing.
Well, to be more precise... The owl doesn't know...right? It's "instincts" know....lol. Owls are one of nature's perfect killing machines. Millions of years coupled with evolution seems to always end up being the best engineer in the world, eh.😉 This is why we engineers often look to nature to solve complex issues. ☺️
@@Sabotage_Labsin most birds there's only very very rudimentary instincts for flying. In most the instinct is more of a "stick your wings out and hope you start gliding by luck" thing. They need to learn by observing the parent(s), then figure it out once they can start doing basic flying. The more they fly the better they get as well. This is why many pet birds cannot fly. They're capable but have either never flown, or haven't flown in such a long time that they've essentially forgotten how. They'll instinctively pull them out for a fall (like you would try and block your fall or pull your hand away from pain), and also sometimes flap them when they want to get up somewhere - but the instinctive flapping is normally so bad it generates virtually no lift, it's likely just there so their brain feels the tiny lift and knows it can improve on that. You can normally train birds like this to fly again, but it's really hard, especially if they were imprinted by humans instead of one of it's own species. In that case you need to teach it to fly without even knowing how yourself (thankfully both humans and most birds have very good general intelligence so they figure out what we're trying to get them to do pretty quickly). It probably needs to be learnt as instincts need to be simple to encode. It's really hard to select for large amounts of genetics for a single specific task, and there's just not that much room in DNA, e.g. the human genome is ~720MB and ~710MB of that is just for the internal cellular machinery. Of course it doesn't think about things like elevators, speed brakes, etc as they're all human concepts for human machines. The bird thinks about flying intuitively, just like pilots "feel" the aircraft (but of course the birds intuition is much stronger because it can literally feel and directly control all of the surfaces. It also doesn't make much sense to try and use plane terminology to try and describe what the bird is doing. They can change the shape of the wing in so many variable and tiny ways. And of course they can do it to each independently, and they often do very weird things that would be hard to analyse aerodynamically, but obviously it makes intuitive sense to them since it works. They're really impressive, e.g. I love the way they force stalls in one or both wings in order to take advantage of it. Would love to see a human attempt at such ridiculously variable wings. Probably too difficult and dangerous for human pilots, but given the recent advances in machine learning I would think it might be suitable for testing such designs.
At 0:47 you can see the cosmic owl creating not one, but two supermassive black holes! Another win for science. Well done researchers! The answers to the origin of the universe are almost within your grasp.
"Canard" aircraft do this as well, but they look weird, because the stabilizer is in the front, and also adds lift as it does its job. Rutan's odd looking, but beautiful airplanes are like that. They don't require active stabilization. The other extreme is helicopters and drones, which require a lot of active stabilization, and it was impossible to build one on a small scale until we had the technology to miniaturize the electronics and position sensing devices needed to do that.
Actually, it is by no means uncommon for model gliders to have lifting tails. Indeed, historically the majority of contest model gliders were designed for and balanced in this way. For high wing aspect ratios (typical of high performance gliders) it is only necessary to arrange that the area loading of the tail is significantly lower than that of the wing for stability to be maintained. However, it was discovered that the advantages of lifting tails was marginal because the tail is operating to a greater or lesser degree in the downwash of the wing. This increases the induced drag of the tail creating a greater drag penalty for the load carried on the tail compared to transferring that load to the wing by using a more forward CG. The wing operates in only about 50% of its own downwash while the tail experiences nearer to 100% of the wings downwash. Additionally, a lifting tail creates its own downwash further increasing the induced drag penalty for lift it generates. This more than anything else is why lifting tails are not as common as they once were.
@@ATruckCampbellbut also vortices are generated on purpose on many modern planes because they reduce the amount of drag by reducing turbulence. Also using owls as a study for flying efficiency is kind of dumb. They have selected for very quiete operation and close to the ground gliding, not for normal flying efficiency. They probably generate these to reduce and manipulate their sound signature, and to increase their ground effect (I'd guess also why they have such a concave shape on the underside of the wings) - and maybe also why they have such a widespread tail. It should also be clear just from the shape of their head lol. That thing is like the bird equivalent of an AWACS. It's hugely inefficient for flying, it's just to mount their stupidly sensitive huge eyes and hearing. I mean they literally have an asymmetric skull so they can better locate sounds, and their entire face is like a radar dish to exploit reflected sounds and possibly light. None of that says flying efficiency, it says short range stealth killing machine. There's a ton of birds that are built almost purely for flying efficiency, and they look completely different.
@@NathanChisholm041 basically, she states that the wingtip vortices aid in the generation of life, but that is completely incorrect as they actually cause a significant reduction of lift and increase in drag, which is why aircraft manufacturers spend so much time designing complicated wingtip devices to reduce the intensity of those vortices. This is one of the first things that are learned when it comes to aircraft design, so this mistake has absolutely no place in a video about aircraft design and aerodynamics research
It looks fancy but the commentary is factually wrong on many levels. We already have planes that actively use all of their control surfaces to improve their effectiveness. Tail fins no longer move just up or down for elevation, thanks to fly-by-wire avionics they (and all other control surfaces) are entirely independent from each other and using computer controls they keep the plane stable in changing conditions. All modern jet fighters utilize this, it's nothing new.
Bro the velocity of the airplanes are very high, for very low velocity and even in turbulent conditions our air crafts cannot fly, but this birds can fly, so bird flight stimulation is necessary.
Actually a lift-generating tail already exists in planes and is a patented design by Piaggio named 3LS for "3 lifting surfaces". Instead of having a main wing with a center of pressure aft of the aircraft center of gravity and a downward-lift generating tail which creates a loss of energy, the main wings, the tail surface and the "mustache" on the nose all provide lift, therfore no loss of energy occurs. For those interested, on the Piaggio Avanti, even the fuselage provides 20% of the total lift. It is one of the most efficient airplanes now :-)
There's a hike that I like to do at night under a full moon. There's a stretch of that trail where an owl always flies about 15 feet over my head, I never hear it coming, and it lets out a screech right over my head that scares the holy crap out of me. EVERY TIME. Thanks for the adrenaline, Mr. or Mrs. Owl.
I came here to see how owls are more evolved in terms of flight capabilities as compared with other birds of prey. However, the video was about something else and as per many comments gave wrong information. Still, the owls are beautiful so I liked it.🦉❤
Passenger planes do make use of this. Before each flight they calculate the weight and center of gravity (CG). The cg must be within a certain zone. The more they can move the cg rearward within this zone, the more efficiently the plane flies because then the tail is generating lift instead of counteracting the lift of the main wing. I don't think you have anything new to tell the engineers here.
If you put your CG that far back that the elevator is producing positive lift your plane would be in an unstable configuration. It would flip like a reverse thrown dart. But yes you can put your CG back (to certain amount) to decrease the needed angle of attack for a given speed and therefore fly more efficiently.
@@michaelderflinger5002 Incorrect. It is not the elevator that produces the relevant amount of lift (positive or negative), it's the horizontal tail. And what Mark said is completely correct. You don't need to generate negative lift from the HT to have a stable aircraft. You just need the center of pressure (of the aircraft, not the wing) behind the center of mass.
Vortices don't create lift, they are just a consequence of lift being created, when a vortice is created we can assume lift is being generated too. Vortices actually create more drag and reduce efficiency
If you spontaneously generate a vortex parallel to the bottom of the wing allowing only the underside to have airflow do you think the pressure above the wing would be greater or smaller than beneath the wing?
@@thesuccessfulone player, i dont know, well on second thought it might, think about, why do geese fly in the vee, you know those votices flare out, maybe they know something that scientists dont!
We still have alot of things to learn from nature. The Japanese engineers observed and even apply the structure of a Kingfisher's beak to bullet trains which made it more energy efficient and alot faster.
Lift creates drag, always. So they generate lift without drag is an erroneous statement. You can reduce the drag, but just having a separate surface to generate lift won’t do that.
Just remember this. Everthing in nature is in its closest to perfect design. When flying my hang glider in thermals its just great to watch the birds head turn and laugh at me.
That's not quite true... Evolution does optimize towards the local minimum of the phasespace, but there are still major design flaws in natural or living systems. For example, in humans, the respiratory and the digestive pathways intersect in the throat, causing a lot of humans to accidentally inhale food and die. We rely on the epiglottis to save our lives every time we swallow. This is not the case in, for example, dolphins, who have the respiratory and digestive openings located far apart.
Everything in nature is most definitely not closest to "perfect" design, but evolutionary pressure does create some extremely efficient biological machinery for certain tasks.
Lovely video but you are completely wrong, lift causes induced drag regardless of where the lift is created however the tip vortices only appear when the owl has made a direction change and so it's pretty reasonable to assume that the tail of the bird is acting in exactly the same way as the tail surfaces of an aircraft and are not just providing stability but also acting as a control surface.
Thanks! I utilized the idea of this research for my car DIY modification. By installing a decent size of diffuser (a third of width of vehicle) and adding vortex generators to the end plates of the existing GT wing, my car got more downforce with a flatten angle of attack at the wing, thereby reduced drag. I can feel the car is more sucked on cornering so that made it more fun to drive!
Some airplanes do produce lift at the tail. The F-16 with it's reduced stability, sometimes lifts slightly depending on the speed and load. This is only possible with very fast controls being overseen by a computer. However birds employ other aerodynamic tricks to self-center themselves and achieve stability without as much parasitic drag or active intervention. Our airplanes use their tail for everything, which is simple and powerful, but relatively inefficient. Birds do much more of their control via the main wings, in a way which we are only starting to understand. There is a reason birds don't have rudders, and they're more efficient for it. But, birds don't have titanium or jet fuel at their disposal, so you've got to give the humans some credit too.
@@THYB737 did you watch the video? This is good for gliders since the birds use the tail the same way planes use the wings. Fighter jets tails are NOTHING like the tails of these birds. They function differently since the birds can generate lift with the wings and tail making the gliding more efficient. A jets tail generates thrust from the actual jet engine and the lift comes from the wing flaps being adjusted. Tail flaps for help with turns and maneuvers. Imagine manually flying a plane with a moving tail. Holy fuck
Really a well made video and a British accent adds no less than 20 IQ point. Imagine engineers mimicking nature and using all horizontal surfaces to generate lift.... perhaps like the canard in the front of the Wright Bothers planes, or those of Burt Rutan. Yeah, that'd be something.
Beautiful! For anyone interested in aerodynamics this is really interesting, and of course birds of prey like the owl are amazing and fascinating. However, people can see this for themselves, by watching seagulls as they ride onshore winds on the coast. They use their tail feathers constantly whilst flying, helping them turn and out manoeuvre their rivals. When they come into land, they spread their tail feathers out into a wide 'delta' shape and angle them down, so as to generate extra lift and bleed off airspeed, so they can land at walking pace. Conversely, whilst they are in flight, they can tuck all of their tail feathers into a very minimal, streamlined shape for extra speed, making fine adjustments to their flight with their wings only. Aircraft designers have long wanted to emulate this astonishingly fine tuned control system for agile, efficient flight, but it is expensive and very challenging to implement. Computerised, 'fly-by-wire' control systems make it possible, but stability is still an issue for 'tail-less' high performance aircraft. Research aircraft have been built with wings that actually twist in a controlled way, but no aircraft in service uses this technology. The current designs that are widely used may seem mundane, but they are stable, safe, and easy to build.
@@manfredschultz9619 yes, good observation, and what an incredible, if somewhat sinister aircraft they are. The design of that aircraft works because it is not supersonic, or intended to be 'agile'. For its size and weight I would guess that it's actually very efficient in flight, although the design remit was, of course, low 'observability' rather than outright efficiency. The fact that it flies at all is an amazing achievement, and testament to the power of modern computerised flight control systems.
Vortices do not produce lift, they create drag. the vortices are formed by the high pressure air escaping to the low pressure zone above the wings. Smooth airflow over their airfoils allows them generate lift using their wings. The vortices are a byproduct.
Saw a video of scientists studying aerodynamics by watching an owl fly through a cloud of tiny bubbles and the pattern / vortex and flow of the waves looks very similar to this one
Using owls as a study for flying efficiency is kind of dumb. They have selected for very quiete operation and close to the ground gliding, not for normal flying efficiency. They probably generate these to reduce and manipulate their sound signature, and to increase their ground effect (I'd guess also why they have such a concave shape on the underside of the wings) - and maybe also why they have such a widespread tail. It should also be clear just from the shape of their head lol. That thing is like the bird equivalent of an AWACS. It's hugely inefficient for flying, it's just to mount their stupidly sensitive huge eyes and hearing. I mean they literally have an asymmetric skull so they can better locate sounds, and their entire face is like a radar dish to exploit reflected sounds and possibly light. None of that says flying efficiency, it says short range stealth killing machine. There's a ton of birds that are built almost purely for flying efficiency, and they look completely different.
Player_1 In very basic terms, a wing generates low pressure above it so the pressure beneath it is higher than in the upper part. A vortex is the result of those two pressures trying to equalize at the tip of the wing.
just a note there are lifting tail designs already and birds are closer to flying wings that already do this "trick" Jack Northrup figured it out years ago
Lift is created by vortex-shedding. But to avoid the beginners' misconceptions, you'd need an actul fluids professor, and NOT someone who teaches undergrads, or introductory aerodynamics. Those people would tell you that the airfoil divides the parcels, and the top of the airfoil must have a longer path, so the parcels can re-join again at the trailing edge. (Today called the "transit-time fallacy." Intro textbooks are full of such mistakes.)
The system is already in use since 1974 with the invention of Fly By Wire on the F 16. The reason civil planes don't use this is because it is forbidden by the regulation FAR 25
@@windowsxseven actually canard are placed in front of the wing. The video talks about the lift produced by the tail. A plane, in order to be stable, has the center of mass placed in front of center of pressure (where the lift force is placed). This means that you have to produce a downwards force in the tail to reach balance. In modern fighter jets (unstable but controlled by a computer) you have the center of mass behind the center of pressure, so every horizontal surface is lifting, providing a better efficiency. The thing about vortices is not completely true, although there is a strong connection between drag and vortices left behind by a plane.
Airlines when they can load their planes with the centre of gravity as far aft as allowable, this enhance performance and economy by reducing the downward force produced by the horizontal stabiliser. This also results in an acceptable loss of pitch stability. They never get to a load configuration where the horizontal stabiliser actually produces upward force or lift.
Burt rutan's airplane designs used the tail for lift decades ago. The trick was to make the main (front) wing have a higher angle of attack so it always stalled before the tail, making it inherently stable. Modern aircraft the tail pushes down when in flight...
What? That was the conclusions? "It makes swirlies and its tail also provides lift." I could have told you that from the footage. I thought they would say the swirlies at the end of the wings stabilize the bird's yaw axis or something. So what you are saying is, we pretty much learned nothing?
The vortex's are not coming off the wing tips, rather just before it, this causes the tips to provide a small amount of thrust, when the Prandtl equation is graphed the area of lift ends in a nice curve, but if the graph is made longer you can notice the equation continues to increase gradually after the curved termination, when applied to the wing you would achieve "Positive Yaw" and would have no need for a vertical stabilizer.
I am no expert, but I always thought that fly-by-wire passenger planes since the first Airbus use lift also from the tail, hence having smaller main wings and saving fuel. I read it in 1990, I remember because I was then doing Erasmus in Glasgow University and I liked to read books at the aeronautics library.
Might have been touted as a possible thing, but it doesn't seem they do do that. If you look at the wing profile of the horizontal stabilizers of almost any passenger jet you'll see they're actually inverted foils in a lot of cases, at least at the root.
Gorgeous images of the aerodynamics of birds, but the commentary is misinformed : - the tail of a plane does produce lift : it actually can vary the lift produced by using the elevator therefore controlling the pitch of the aircraft. - wingtip vortex reduce lift (since if decreases the pressure under the wing and increases the pressure on the top of the wing) and increase drag (induced drag)
I just realized that the bird increases the angle of attack of both its wings and its tail to increase the lift and rise just before passing over the camera
Ahh, anyone who has ever watched a bird fly knows the tail gets used as a lifting surface. Pitch is controlled mostly by moving the wings forward and back. If the tail was used for pitch, it would come up during landing flare to raise the nose. It comes down, while the wings swing forward. This video appears to be by people who know nothing about birds, or aerodynamics, but the bubbles were pretty.
@@thesuccessfulone well on an aircraft, which doesn't control pitch by moving the wings forward and back, lifting the tail (elevator) pushes the tail down, and the nose up. Birds don't do that.
@@thesuccessfulone yeah, basically that's how an aircraft is controlled in pitch. If you watch a plane take off, it trundles down the runway, and when it's going fast enough, the back of the tail, (called elevators on a plane) lift up. That pushes the tail down, the plane pivots on the wheels and lifts the nose. Because the wings are fixed to the body of the plane, that means the wings pitch up. The front of the wing is now higher than the back of the wing. So as it hits the air it throws the air down. That pushes the wing up, and the plane takes off.
@@thesuccessfulone you can see it pretty clearly in this video. The tail is set quite a long way up during takeoff to lift the nose. ua-cam.com/video/a8iDMvkfl9Q/v-deo.html ua-cam.com/video/a8iDMvkfl9Q/v-deo.html
In this experiment, the birds know that they are flying in confined spaces and therefore use the main wings for relative lift to keep a relative altitude and use the tail to control pitch, very much like a regular aircraft, so this clip confuses the general public.
The direction of the swirls shows that the tail is generateing lift rather than downforce. I am puzzling over how the bird is stable (unless it isnt and the flight computer/brain is good enoigh). Cannards do the same thing at the front of an aircraft.
Newtonian physics. Action and reaction is numerically equal but opposite. The bird accelerate air downward (action) and the resultant equal reaction upward is called lift
For an aircraft to be stable and easy to fly the centre of gravity must be forward of the centre of lift. Unfortunately this causes a nose down pitching moment that the tail must correct by producing a down force (negative lift). Since total lift must equal weight this means the wing must produce more lift than strictly necessary. This in turn means its creating more drag and burning more fuel than necessary. So we would like to move the centre of gravity back and fix the stability problem this would cause some other way (eg by using a computer). This has been known for decades, I guess we just didn't know birds could do it without one. Edit: This is a bit of an over simplified explanation.
It means God is twice as good at creating birds and didn't have to make a mark 2 anything. And we are learning to copy these ideas without crediting the designer. Nice touch mapping the helium balloons.
You can see the same effect made by an airplane at the end of the movie "Die Hard II." A wonderful vortex of smoke and snow created by the wing of a plane is captured on film.
I wonder if this is akin to the way the alternating vortices generated from a fish tail push against each other to generate more thrust. I wish this video was more specific and told us how much difference having the second set of vortices made. 2%? 30%?
Sorry, this video makes absolutely no sense. I'm an aerospace engineer. You can't decrease drag by generating more lift. In fact, increasing lift increases a component of drag called induced drag.
Surely aircraft tails DO produce lift, don't they? The stabilizer has movable fins on it (elevators?). If the fins are moved to create more lift, the nose of the plane will drop and the plane will descend.
![Lp. Сердце Вселенной #60 РОЖДЕНИЕ ЛОЛОЛОШКИ [Финал] • Майнкрафт](http://i.ytimg.com/vi/YoR0pAV9FVQ/mqdefault.jpg)
What I love most is that the birds are thanked in the credits.
Hear. Hear!
Yeah, wasn't that a hoot?! 🦉
Bird - Played as the bird.
😂
They will appreciate it for sure....
Nice video. I in particular liked the part when the LED was turned on too early and the bird saw a white "wall" and tried to land on it. This was not (of course) involved in the original paper and I appreciate this footage. I'd like to point out 3 things on the video, though: (1) The wingtip vortices do not "helps provide lift". They are unavoidable byproduct of producing lift with a finite span wing, and they actually cause the induced drag. (2) It's not the lift but the *lift coefficient* that is distributed more evenly over the body (spanwise). Please see the red lines in figure 5 of the paper. This is the whole point of the paper... (3) The video acknowledges 2 professors but not the 2 postdocs who played the major roles in the experiments and analysis. No mentioning on the LaVision (equipment company) people either, who not only provided the software/hardware but actively involved in the experiments.
Things fly by pushing air down. The physics is why the shapes work well, or badly, but the basics are simple 😀
@@RobertSzasz pulling air down, inversely to a straw that pulls up
Note how the vortices were not on the wingtip, but inboard. This is why birds don't need vertical stabilizers. Prandtl figured out how to reduce induced drag even more than his elliptical lift distribution, but it was practically ignored for 80-90 years. Look up NASA Armstrong Flight Research Center's flying wing called the Prandtl for more info.
Also, lift increases drag so I don't know what they meant by "decreasing drag." The least amount of drag would be the tail pointing straight back, parallel with the airflow.
@@nelsonphillips the bottom surface of the wing pushes air down, while the air above the wing rushes to fill the low pressure hole that the wing just pushed into the air. And if the wing is an aerofoil shape, it will add more lift that way.
It's just the same as a propeller or fan.
Does it work by pushing air in front of it, or sucking air?
And if you say by sucking air, how come a non aerofoil blade or wing can still work? Lol
To put it another way, if you stick your hand out the window while driving down the road, do you feel more pressure on the front, or suction on the back?
The vortices from the wings do NOT generate lift. They are an effect of lift. They generate induced drag and reduce the effectiveness of wings.
*vortex,basically a vortex eliminates turbulence,and by that reduces drag,yes it still creates drag,but much lesser than turbulence
you are right.
They are not really an effect of lift either. More what lift *looks like*.
When I was doing my PPL the tailplane was used to change the pitch of a/c by using the elevators to increase or decrease the amount of lift it produced. The video seems to be somewhat underinformed.
There was one other thing that they got wrong. Aircraft wings do provide lift! That is how an aircraft can be pitched up or down. By increasing the lift in the elevator the nose is pitched down.
Isn't it more that the vortices are a side effect of producing lift but they themselves actually increase drag?
Yes.
Exactly... the explanation in the video is incorrect.
Not necessarily. It depends where they are in relationship to nearby flying surfaces. Wingtip sails on gliders and airliners reduce drag by interacting with the wingtip trailing vortices.
Yes, I think the narrator's statement on 0:58 is incorrect ('as expected the researchers saw vortices spinning down from the wingtips, this helps provide lift..."). I was taught that ground effect glide on final on a glider is achieved by maximizing lift through compression of the air underneath the wing against the ground and REDUCTION of drag by partial elimination of wingtip vortices. A bigger vortex implies bigger drag as the wing passes through the air. It doesn't create lift.
I think who wrote the script had in mind the circulation theorem. The pair of vortices that is the signature of induced drag is really the same vortex that produces the lift. Thus, the narrator is not really wrong when she said "this helps provide lift". But it's kinda confusing to people who know practical aerodynamics but not the theory. But let's be honest, they've tried their best, the internet will always be smarter than the small team in the production!
The first time I'm seeing an actual vector field
Fluid dynamics are beautiful
@@FullAfterburner You should totally make a video on that
You just got vectored
@@FullAfterburner could you tell me more about it? I'm doing electrical Engineering and this sound as a interesting project to develop
@@FullAfterburner so, I'm starting te new differential equations course and fluid dynamics this semester, hope will go well.I'm gonna try to do projects like yours, have a great day.
*Aero engineers hate him.* Owl reduces drag with this one weird trick:
Yes! This comment 😂😂 you made my day
Perfect!
Seriously underrated joke! 😄
He was adorable as a baby owl on UA-cam, when you see what he looks like today you'll be shocked!
Haha
I love how this video describes an aircraft elevator's purpose in stabilizing flight and makes it sound like a new discovery when even the very first aircraft had it 😂
The goes on to suggest wingtip vortices create lift when in fact lift creates vortices which aircraft designers want to minimize.
The bird is producing a momentary "down elevator" control exactly when passing the bubbles @0:59 and that's why there is a second vortex pair formed. The bird "knows" exactly to keep it's tail "idle" and not creating any lift as the main wings are much more efficient at creating lift than the tail - this knowledge is shared with most aircraft designers. What the Owl does and no plane can do, is to use the tail as flaps, to supplement lift at slow flight and this is because it can move the wings to control and balance the centre of pressure in relation to centre of gravity. Tail providing lift is a way to make any flight inefficient as it increases the energy spent in air vortex, but at slow speed the Owl needs as much lift as possible, and it's a good way to slow down before landing.
I think it was air brake. To increase drag for landing.
Well, to be more precise... The owl doesn't know...right? It's "instincts" know....lol. Owls are one of nature's perfect killing machines. Millions of years coupled with evolution seems to always end up being the best engineer in the world, eh.😉 This is why we engineers often look to nature to solve complex issues. ☺️
Nice innovative video, nice.visualization of the airflow. But the description is below par.
@@Sabotage_Labsin most birds there's only very very rudimentary instincts for flying. In most the instinct is more of a "stick your wings out and hope you start gliding by luck" thing. They need to learn by observing the parent(s), then figure it out once they can start doing basic flying. The more they fly the better they get as well.
This is why many pet birds cannot fly. They're capable but have either never flown, or haven't flown in such a long time that they've essentially forgotten how. They'll instinctively pull them out for a fall (like you would try and block your fall or pull your hand away from pain), and also sometimes flap them when they want to get up somewhere - but the instinctive flapping is normally so bad it generates virtually no lift, it's likely just there so their brain feels the tiny lift and knows it can improve on that. You can normally train birds like this to fly again, but it's really hard, especially if they were imprinted by humans instead of one of it's own species. In that case you need to teach it to fly without even knowing how yourself (thankfully both humans and most birds have very good general intelligence so they figure out what we're trying to get them to do pretty quickly).
It probably needs to be learnt as instincts need to be simple to encode. It's really hard to select for large amounts of genetics for a single specific task, and there's just not that much room in DNA, e.g. the human genome is ~720MB and ~710MB of that is just for the internal cellular machinery.
Of course it doesn't think about things like elevators, speed brakes, etc as they're all human concepts for human machines. The bird thinks about flying intuitively, just like pilots "feel" the aircraft (but of course the birds intuition is much stronger because it can literally feel and directly control all of the surfaces.
It also doesn't make much sense to try and use plane terminology to try and describe what the bird is doing. They can change the shape of the wing in so many variable and tiny ways. And of course they can do it to each independently, and they often do very weird things that would be hard to analyse aerodynamically, but obviously it makes intuitive sense to them since it works.
They're really impressive, e.g. I love the way they force stalls in one or both wings in order to take advantage of it. Would love to see a human attempt at such ridiculously variable wings. Probably too difficult and dangerous for human pilots, but given the recent advances in machine learning I would think it might be suitable for testing such designs.
At 0:47 you can see the cosmic owl creating not one, but two supermassive black holes! Another win for science. Well done researchers! The answers to the origin of the universe are almost within your grasp.
"Canard" aircraft do this as well, but they look weird, because the stabilizer is in the front, and also adds lift as it does its job. Rutan's odd looking, but beautiful airplanes are like that. They don't require active stabilization. The other extreme is helicopters and drones, which require a lot of active stabilization, and it was impossible to build one on a small scale until we had the technology to miniaturize the electronics and position sensing devices needed to do that.
Actually, it is by no means uncommon for model gliders to have lifting tails. Indeed, historically the majority of contest model gliders were designed for and balanced in this way. For high wing aspect ratios (typical of high performance gliders) it is only necessary to arrange that the area loading of the tail is significantly lower than that of the wing for stability to be maintained. However, it was discovered that the advantages of lifting tails was marginal because the tail is operating to a greater or lesser degree in the downwash of the wing. This increases the induced drag of the tail creating a greater drag penalty for the load carried on the tail compared to transferring that load to the wing by using a more forward CG. The wing operates in only about 50% of its own downwash while the tail experiences nearer to 100% of the wings downwash. Additionally, a lifting tail creates its own downwash further increasing the induced drag penalty for lift it generates. This more than anything else is why lifting tails are not as common as they once were.
As someone who is currently studying fluid dynamics it is amazing to see this!
Do not listen to this video if you are studying aerodynamics.
Vortices do not generate lift, they actually create drag, aircraft designers have been trying to eliminate that drag for 80 years or better.
Heathrow on a drizzely, misty is an excellent place to see vortices.
There are YT videos.
@@ATruckCampbellbut also vortices are generated on purpose on many modern planes because they reduce the amount of drag by reducing turbulence.
Also using owls as a study for flying efficiency is kind of dumb. They have selected for very quiete operation and close to the ground gliding, not for normal flying efficiency. They probably generate these to reduce and manipulate their sound signature, and to increase their ground effect (I'd guess also why they have such a concave shape on the underside of the wings) - and maybe also why they have such a widespread tail.
It should also be clear just from the shape of their head lol. That thing is like the bird equivalent of an AWACS. It's hugely inefficient for flying, it's just to mount their stupidly sensitive huge eyes and hearing. I mean they literally have an asymmetric skull so they can better locate sounds, and their entire face is like a radar dish to exploit reflected sounds and possibly light.
None of that says flying efficiency, it says short range stealth killing machine. There's a ton of birds that are built almost purely for flying efficiency, and they look completely different.
She has no idea what she's talking about
Please enlighten us?
I'm glad 99% of the comments agree she is completely wrong
@@NathanChisholm041 basically, she states that the wingtip vortices aid in the generation of life, but that is completely incorrect as they actually cause a significant reduction of lift and increase in drag, which is why aircraft manufacturers spend so much time designing complicated wingtip devices to reduce the intensity of those vortices. This is one of the first things that are learned when it comes to aircraft design, so this mistake has absolutely no place in a video about aircraft design and aerodynamics research
@@chixinspace I was led to believe that vortices cause vortex drag on the aircraft thus slowing it down!
@@NathanChisholm041 what you have been led to believe is correct, were talking about the same thing here
It looks fancy but the commentary is factually wrong on many levels. We already have planes that actively use all of their control surfaces to improve their effectiveness. Tail fins no longer move just up or down for elevation, thanks to fly-by-wire avionics they (and all other control surfaces) are entirely independent from each other and using computer controls they keep the plane stable in changing conditions. All modern jet fighters utilize this, it's nothing new.
yes
Bro the velocity of the airplanes are very high, for very low velocity and even in turbulent conditions our air crafts cannot fly, but this birds can fly, so bird flight stimulation is necessary.
Actually a lift-generating tail already exists in planes and is a patented design by Piaggio named 3LS for "3 lifting surfaces". Instead of having a main wing with a center of pressure aft of the aircraft center of gravity and a downward-lift generating tail which creates a loss of energy, the main wings, the tail surface and the "mustache" on the nose all provide lift, therfore no loss of energy occurs.
For those interested, on the Piaggio Avanti, even the fuselage provides 20% of the total lift. It is one of the most efficient airplanes now :-)
There is a video on the owl and how it is able to fly near silently compared to other birds, all very interesting.
Owls turn off the microphone.
ua-cam.com/video/d_FEaFgJyfA/v-deo.html
vortex generators on wings
There's a hike that I like to do at night under a full moon. There's a stretch of that trail where an owl always flies about 15 feet over my head, I never hear it coming, and it lets out a screech right over my head that scares the holy crap out of me. EVERY TIME. Thanks for the adrenaline, Mr. or Mrs. Owl.
I came here to see how owls are more evolved in terms of flight capabilities as compared with other birds of prey. However, the video was about something else and as per many comments gave wrong information. Still, the owls are beautiful so I liked it.🦉❤
This is one of the most uninformed videos ever.
This is so cool. Those vortices in the soap bubbles look like 2 galaxies spinning in the vastness of the empty universe.
.
I sincerely hope those are not soap bubbles
I appreciate the thanks to the birds.
engineering that takes inspiration from nature is called biomimicry
it looks like the owl is interstella and just spawned 2 black holes
Passenger planes do make use of this. Before each flight they calculate the weight and center of gravity (CG). The cg must be within a certain zone. The more they can move the cg rearward within this zone, the more efficiently the plane flies because then the tail is generating lift instead of counteracting the lift of the main wing. I don't think you have anything new to tell the engineers here.
If you put your CG that far back that the elevator is producing positive lift your plane would be in an unstable configuration. It would flip like a reverse thrown dart.
But yes you can put your CG back (to certain amount) to decrease the needed angle of attack for a given speed and therefore fly more efficiently.
and Flying wings are even better jack northrop figured this out at the end of WWII
these guys have just rediscovered the canard configuration
@@michaelderflinger5002 Incorrect. It is not the elevator that produces the relevant amount of lift (positive or negative), it's the horizontal tail. And what Mark said is completely correct. You don't need to generate negative lift from the HT to have a stable aircraft. You just need the center of pressure (of the aircraft, not the wing) behind the center of mass.
@@windowsxseven These birds are not canards. Canard has the stabilizer in front of the wing. Not even a duck is a canard, on this sense.
The 2 vortices look like the owl's face. They also look like black holes in space...
My god, please watch this making sure the sound is OFF
Active tail stabalization is already a technique in aviation and used in many smaller planes.
A model plane has done this very thing for many years. It is called the Telemaster and has a lifting horizontal stabilizer and several others.
Vortices don't create lift, they are just a consequence of lift being created, when a vortice is created we can assume lift is being generated too. Vortices actually create more drag and reduce efficiency
If you spontaneously generate a vortex parallel to the bottom of the wing allowing only the underside to have airflow do you think the pressure above the wing would be greater or smaller than beneath the wing?
@@thesuccessfulone Player, that vortice is i think way behind the the wing, it just looks like its under the wing.
@@lendavidhart9710 but if it were under, would it not generate lift?
@@thesuccessfulone player, i dont know, well on second thought it might, think about, why do geese fly in the vee, you know those votices flare out, maybe they know something that scientists dont!
@@lendavidhart9710 I think the thing we call "drag" is just lift but in the downward direction.
We still have alot of things to learn from nature. The Japanese engineers observed and even apply the structure of a Kingfisher's beak to bullet trains which made it more energy efficient and alot faster.
I saw you before in another comment sections. How is that possible, that's spooky lol
Lift creates drag, always. So they generate lift without drag is an erroneous statement. You can reduce the drag, but just having a separate surface to generate lift won’t do that.
Just remember this. Everthing in nature is in its closest to perfect design.
When flying my hang glider in thermals its just great to watch the birds head turn and laugh at me.
That's not quite true... Evolution does optimize towards the local minimum of the phasespace, but there are still major design flaws in natural or living systems. For example, in humans, the respiratory and the digestive pathways intersect in the throat, causing a lot of humans to accidentally inhale food and die. We rely on the epiglottis to save our lives every time we swallow. This is not the case in, for example, dolphins, who have the respiratory and digestive openings located far apart.
Everything in nature is most definitely not closest to "perfect" design, but evolutionary pressure does create some extremely efficient biological machinery for certain tasks.
Lovely video but you are completely wrong, lift causes induced drag regardless of where the lift is created however the tip vortices only appear when the owl has made a direction change and so it's pretty reasonable to assume that the tail of the bird is acting in exactly the same way as the tail surfaces of an aircraft and are not just providing stability but also acting as a control surface.
the lift from the tail is just about essential, especially when carrying another animal that is about to be a meal. very cool video.
Thanks! I utilized the idea of this research for my car DIY modification. By installing a decent size of diffuser (a third of width of vehicle) and adding vortex generators to the end plates of the existing GT wing, my car got more downforce with a flatten angle of attack at the wing, thereby reduced drag. I can feel the car is more sucked on cornering so that made it more fun to drive!
This also happens when you poop underwater and try to swim fast
Some airplanes do produce lift at the tail. The F-16 with it's reduced stability, sometimes lifts slightly depending on the speed and load. This is only possible with very fast controls being overseen by a computer. However birds employ other aerodynamic tricks to self-center themselves and achieve stability without as much parasitic drag or active intervention. Our airplanes use their tail for everything, which is simple and powerful, but relatively inefficient. Birds do much more of their control via the main wings, in a way which we are only starting to understand. There is a reason birds don't have rudders, and they're more efficient for it.
But, birds don't have titanium or jet fuel at their disposal, so you've got to give the humans some credit too.
Engineers have been using this idea for years on fighter jets.
Which fighter jet uses it's horizontal stabilizer to generate lift in cruise (not ascending/descending) flight conditions?
Fighter jets aren't gliders
Decades
@@Handlebarrz you are totally lost
@@THYB737 did you watch the video? This is good for gliders since the birds use the tail the same way planes use the wings. Fighter jets tails are NOTHING like the tails of these birds. They function differently since the birds can generate lift with the wings and tail making the gliding more efficient. A jets tail generates thrust from the actual jet engine and the lift comes from the wing flaps being adjusted. Tail flaps for help with turns and maneuvers. Imagine manually flying a plane with a moving tail. Holy fuck
Really a well made video and a British accent adds no less than 20 IQ point.
Imagine engineers mimicking nature and using all horizontal surfaces to generate lift.... perhaps like the canard in the front of the Wright Bothers planes, or those of Burt Rutan. Yeah, that'd be something.
Beautiful! For anyone interested in aerodynamics this is really interesting, and of course birds of prey like the owl are amazing and fascinating. However, people can see this for themselves, by watching seagulls as they ride onshore winds on the coast. They use their tail feathers constantly whilst flying, helping them turn and out manoeuvre their rivals. When they come into land, they spread their tail feathers out into a wide 'delta' shape and angle them down, so as to generate extra lift and bleed off airspeed, so they can land at walking pace. Conversely, whilst they are in flight, they can tuck all of their tail feathers into a very minimal, streamlined shape for extra speed, making fine adjustments to their flight with their wings only.
Aircraft designers have long wanted to emulate this astonishingly fine tuned control system for agile, efficient flight, but it is expensive and very challenging to implement. Computerised, 'fly-by-wire' control systems make it possible, but stability is still an issue for 'tail-less' high performance aircraft. Research aircraft have been built with wings that actually twist in a controlled way, but no aircraft in service uses this technology.
The current designs that are widely used may seem mundane, but they are stable, safe, and easy to build.
richie1326
Seems only those Stealth Bombers currently have the “tail-less” design
@@manfredschultz9619 yes, good observation, and what an incredible, if somewhat sinister aircraft they are. The design of that aircraft works because it is not supersonic, or intended to be 'agile'.
For its size and weight I would guess that it's actually very efficient in flight, although the design remit was, of course, low 'observability' rather than outright efficiency. The fact that it flies at all is an amazing achievement, and testament to the power of modern computerised flight control systems.
birbs
In this video the vortices were not coming from the wing tips. They were coming from about .75 of the length of the wing.
Vortices do not produce lift, they create drag. the vortices are formed by the high pressure air escaping to the low pressure zone above the wings. Smooth airflow over their airfoils allows them generate lift using their wings. The vortices are a byproduct.
Saw a video of scientists studying aerodynamics by watching an owl fly through a cloud of tiny bubbles and the pattern / vortex and flow of the waves looks very similar to this one
Sometimes it surprises me what researchers are surprised by.
Using owls as a study for flying efficiency is kind of dumb. They have selected for very quiete operation and close to the ground gliding, not for normal flying efficiency. They probably generate these to reduce and manipulate their sound signature, and to increase their ground effect (I'd guess also why they have such a concave shape on the underside of the wings) - and maybe also why they have such a widespread tail.
It should also be clear just from the shape of their head lol. That thing is like the bird equivalent of an AWACS. It's hugely inefficient for flying, it's just to mount their stupidly sensitive huge eyes and hearing. I mean they literally have an asymmetric skull so they can better locate sounds, and their entire face is like a radar dish to exploit reflected sounds and possibly light.
None of that says flying efficiency, it says short range stealth killing machine. There's a ton of birds that are built almost purely for flying efficiency, and they look completely different.
Engineers have created Canards which mimic the same thing. It's just that they're in front of the wing instead of in the tail.
Vortices don’t generate lift. Vortices a result of lift
Okay, but explain how a vortex beneath a wing wouldn't lift it.
Player_1 In very basic terms, a wing generates low pressure above it so the pressure beneath it is higher than in the upper part. A vortex is the result of those two pressures trying to equalize at the tip of the wing.
@@carlossvazquezz How would a vortex not lift it?
just a note there are lifting tail designs already and birds are closer to flying wings that already do this "trick" Jack Northrup figured it out years ago
Should have gotten a professor in fluid dynamics explaining this!!
Vortices producing lift??
Hahahahahahahaha
Lift is created by vortex-shedding. But to avoid the beginners' misconceptions, you'd need an actul fluids professor, and NOT someone who teaches undergrads, or introductory aerodynamics. Those people would tell you that the airfoil divides the parcels, and the top of the airfoil must have a longer path, so the parcels can re-join again at the trailing edge. (Today called the "transit-time fallacy." Intro textbooks are full of such mistakes.)
So glad I start at Embry-Riddle next year, stuff like this is so exciting and interesting
Vortices increase lift at lower speeds but also increase induced drag because of higher downwash. However they do reduce turbulence.
The system is already in use since 1974 with the invention of Fly By Wire on the F 16. The reason civil planes don't use this is because it is forbidden by the regulation FAR 25
This.
yep, this video talks about what essentially is a glorified canard, plus the additional incorrect physics
@@j.f.fisher5318 thanks
@@windowsxseven actually canard are placed in front of the wing. The video talks about the lift produced by the tail. A plane, in order to be stable, has the center of mass placed in front of center of pressure (where the lift force is placed). This means that you have to produce a downwards force in the tail to reach balance. In modern fighter jets (unstable but controlled by a computer) you have the center of mass behind the center of pressure, so every horizontal surface is lifting, providing a better efficiency. The thing about vortices is not completely true, although there is a strong connection between drag and vortices left behind by a plane.
It is not forbidden by Part 25
Airlines when they can load their planes with the centre of gravity as far aft as allowable, this enhance performance and economy by reducing the downward force produced by the horizontal stabiliser. This also results in an acceptable loss of pitch stability. They never get to a load configuration where the horizontal stabiliser actually produces upward force or lift.
Burt rutan's airplane designs used the tail for lift decades ago.
The trick was to make the main (front) wing have a higher angle of attack so it always stalled before the tail, making it inherently stable.
Modern aircraft the tail pushes down when in flight...
So essentialy canards wings ? Or fly by wire unstable aircraft ? Those already exist , but maybe this will help us icrease their efficency
What? That was the conclusions? "It makes swirlies and its tail also provides lift." I could have told you that from the footage. I thought they would say the swirlies at the end of the wings stabilize the bird's yaw axis or something. So what you are saying is, we pretty much learned nothing?
Did you read the paper?
@@TCA17 Reading is for chumps.
@@tristunalekzander5608 Rock on 👌🏼
@@tristunalekzander5608 well keep in mind that whoever wrote this had zero clue what they were talking about
The vortex's are not coming off the wing tips, rather just before it, this causes the tips to provide a small amount of thrust, when the Prandtl equation is graphed the area of lift ends in a nice curve, but if the graph is made longer you can notice the equation continues to increase gradually after the curved termination, when applied to the wing you would achieve "Positive Yaw" and would have no need for a vertical stabilizer.
Do you have a link to this? This video doesn't seem to illustrate the actual formation of the vortices very well as it's a bit low res
I am no expert, but I always thought that fly-by-wire passenger planes since the first Airbus use lift also from the tail, hence having smaller main wings and saving fuel. I read it in 1990, I remember because I was then doing Erasmus in Glasgow University and I liked to read books at the aeronautics library.
Might have been touted as a possible thing, but it doesn't seem they do do that. If you look at the wing profile of the horizontal stabilizers of almost any passenger jet you'll see they're actually inverted foils in a lot of cases, at least at the root.
it makes"lift" just to compensate CG that can go more far from neutral/stable point
It's not a "toy" plane.
It's a Bob Martin Talon slope soarer. I have one that uses JATO
Easy there Heinrich Dorfman
As soon as she said "toy" I turned off her . An aerodynamicist would never call a flying model a toy.
Model aircraft have been flying with lifting horizontal stablizers since the 1920 and 30s and they are very stable.
I love how birds fly.
Gorgeous images of the aerodynamics of birds, but the commentary is misinformed :
- the tail of a plane does produce lift : it actually can vary the lift produced by using the elevator therefore controlling the pitch of the aircraft.
- wingtip vortex reduce lift (since if decreases the pressure under the wing and increases the pressure on the top of the wing) and increase drag (induced drag)
Thank you
I just realized that the bird increases the angle of attack of both its wings and its tail to increase the lift and rise just before passing over the camera
because cg goes to rear
Ahh, anyone who has ever watched a bird fly knows the tail gets used as a lifting surface. Pitch is controlled mostly by moving the wings forward and back. If the tail was used for pitch, it would come up during landing flare to raise the nose. It comes down, while the wings swing forward.
This video appears to be by people who know nothing about birds, or aerodynamics, but the bubbles were pretty.
How does bringing up the tail raise the nose?
@@thesuccessfulone well on an aircraft, which doesn't control pitch by moving the wings forward and back, lifting the tail (elevator) pushes the tail down, and the nose up. Birds don't do that.
@@gasdive Pushing the tail down and the nose up?
@@thesuccessfulone yeah, basically that's how an aircraft is controlled in pitch. If you watch a plane take off, it trundles down the runway, and when it's going fast enough, the back of the tail, (called elevators on a plane) lift up. That pushes the tail down, the plane pivots on the wheels and lifts the nose. Because the wings are fixed to the body of the plane, that means the wings pitch up. The front of the wing is now higher than the back of the wing. So as it hits the air it throws the air down. That pushes the wing up, and the plane takes off.
@@thesuccessfulone you can see it pretty clearly in this video. The tail is set quite a long way up during takeoff to lift the nose.
ua-cam.com/video/a8iDMvkfl9Q/v-deo.html
ua-cam.com/video/a8iDMvkfl9Q/v-deo.html
In this experiment, the birds know that they are flying in confined spaces and therefore use the main wings for relative lift to keep a relative altitude and use the tail to control pitch, very much like a regular aircraft, so this clip confuses the general public.
The direction of the swirls shows that the tail is generateing lift rather than downforce. I am puzzling over how the bird is stable (unless it isnt and the flight computer/brain is good enoigh).
Cannards do the same thing at the front of an aircraft.
interesting to see that the vortices of owls are much smaller causing less noise
Newtonian physics. Action and reaction is numerically equal but opposite. The bird accelerate air downward (action) and the resultant equal reaction upward is called lift
So they throw footballs while flying?
For an aircraft to be stable and easy to fly the centre of gravity must be forward of the centre of lift. Unfortunately this causes a nose down pitching moment that the tail must correct by producing a down force (negative lift). Since total lift must equal weight this means the wing must produce more lift than strictly necessary. This in turn means its creating more drag and burning more fuel than necessary. So we would like to move the centre of gravity back and fix the stability problem this would cause some other way (eg by using a computer). This has been known for decades, I guess we just didn't know birds could do it without one. Edit: This is a bit of an over simplified explanation.
Props to the person who had to blow 20,000 helium bubbles
Very interesting. I can’t help wonder what it is like to breath the bubbles. I suppose it would just be a bit of soap. A little helium shouldn’t hurt.
The bubbles are so tiny and the soap is so dilute that you probably wouldn't even notice the soap. Or the helium.
The Vortices are shadow evidences of the drag from the wings of the owls; the shadow vortices are not the lift.
No bubbles were harmed in this video.
Nature is such an ingenious engineer.
The point here is that birds have no rudder and are more susceptible to side slipping.
Shortly: Birds can move.
It means God is twice as good at creating birds and didn't have to make a mark 2 anything. And we are learning to copy these ideas without crediting the designer.
Nice touch mapping the helium balloons.
Well said.
No, it is called evolution and natural selection.
@@Sauromannen ua-cam.com/video/W1_KEVaCyaA/v-deo.html
An owl flew right past my head in the wilderness, there was no sound (zero) as it approached and a 'whoosh' as it passed.
Modern flight control computers allow inherently unstable aircraft to be flown with no trouble, so expect this to be used in the near future.
Nice to see the comments having more knowledge than whoever wrote this video
*one hawk was scared by producing this video*
You can see the same effect made by an airplane at the end of the movie "Die Hard II." A wonderful vortex of smoke and snow created by the wing of a plane is captured on film.
Modern fighter jets already do this. They are statically unstable and can only fly with a computer that constantly adjusts the tail, just like a bird.
Wow, this looks like the same effect you see on aircraft. They are nearly identical.
I thought I might of had a stroke. None of this made sense to me. Then I read the comments.
"The vortexes looked like a owl face"
Lights flash on. Birb: "Aaarrrrgh bubbles!!!"
Lights flash on. Yooman: "Aaarrrrgh spiders!!!"
I wonder if this is akin to the way the alternating vortices generated from a fish tail push against each other to generate more thrust. I wish this video was more specific and told us how much difference having the second set of vortices made. 2%? 30%?
The owl should receive royalty for copying his wing design
Anyone who watches this video and knew nothing of lift beforehand is now significantly more ignorant.
Sorry, this video makes absolutely no sense. I'm an aerospace engineer. You can't decrease drag by generating more lift. In fact, increasing lift increases a component of drag called induced drag.
Thats a whole lot a induced drag there. Not increasing efficiency with that one.
Don't tails on both birds and planes generate lift every time they angle the elevator downward or point the tail downward in the case of birds?
That was awesome. What it does with its tail was cool.
Great piece. Fascinating.
This is a nice analogy to what black matter would look like moving around galaxies and other universal systems.
The F22 has lift producing flaps on the tail. It just needs to be actively managed. Allows for supersonic flight without afterburners.
Waow. Love the vortex. Class looking
Surely aircraft tails DO produce lift, don't they? The stabilizer has movable fins on it (elevators?). If the fins are moved to create more lift, the nose of the plane will drop and the plane will descend.
Looks like the vortices start slightly inboard of the wingtips. 🤔
I was wondering if anybody else would notice. Of course it would be someone who already knows that. ;)
Good catch :) See Al Bowers' lectures on Prandtl wing design for details.
@@dekutree64 I've heard Al talk about this for dozens of hours. 😉