Was saying to myself "there has to be more wind downward to support the glider weight if it's "balanced" " then you said the very same. Theory of flight is one thing I understand quite well, but these videos explain it very well for those not so sure. Nice work
Actually Bernoulli's principle is an application of Newton's laws for inviscid and incompressable fluids. So only wrong thing about the Bernoulli's priciple explanation is the principle is too abstract to visualize. You cannot guess which part has low pressure or higher velocity. However with good understanding of Coanda effect, everybody can visualize where the lift is and how the air moves. Thanks for this video, this is a great help for people who starts paragliding and wants to learn the physics behind it.
Great job explaining the principles! It's always really good to understand what's happening. But I feel like the system you showed here might be a little complicated to use in practice, because it's not tied directly to the required inputs or the feedback you get from the wing. To use this system I feel like one needs to convert the knowledge into inputs, observe the wing accelerating, understand that the balance of air spilling downwards and upwards is distrubed in this way and then start thinking of putting the appropriate input. (Mind you, maybe your brain is wired better for this kind of thinking than mine is :D ) I use airspeed over the wing as the parameter to control indirectly. There are two things that influence it when ground handling: wing loading ie how much tension there is on the lines and angle of attack/drag from brake inputs and pulling A's (sorry for the obvious statement :P ). This way if the wing is pulls you less strongly you know that the airspeed is going to drop so you need to take a step back to keep the wing flying and adjust brakes. The critical thing I think is getting a good feeling for the tension on the lines and tying your reactions to the feedback from the wing and not to your processed understanding of what is happening. This shortens the reaction time considerably. Also, there is usually a slight delay between the feeling on the lines and the reaction of the wing so this way you are ready to or already giving the right inputs before the wing starts moving in a new direction. And another key advantage is that in a tricky situation like a rotory launch or something, you react with very little processing. Left side pulls too much - slow it down immediately by brake or moving your feet. Wing doesn't pull hard enough - the wind died down a little and you need to take a few steps back to bring it overhead. This is just the way I found most effective to think about this, it might be different for other people. Anyway, apologies for the long comment, great videos and keep them coming!
Apologies not accepted! Long comments are great and I think what you're saying makes a lot of sense. It's one thing rationalizing it when sitting at a computer, but when I'm actually groundhandling I think my thought process is very similar to what you described! A lot more tension based and "feeling". Thank you so much for sharing!
Good thing our human brains are simplly pattern recognition devices. We don´t need to know or understand the physics in order to practice practice practie! It´s only practice that will develop our nervous systems with the fast reaction time needed to get the desired results. Studying the physics is a super super fun way to geek out though!
To understand lift and drag intuitively try handling sheets of plywood in a stiff breeze. That's all there is to it really. The shape of the wing makes the lift / drag ratio better and affects the handling characteristics (changes in forces generated) at low or high angles of incidence (angle the air hits the surface). Hold the plywood sheet, edge to the wind and it'll just pull back a bit and fall. Tilt the front edge up and the whole sheet will start pushing up. Keep tilting it and it'll start pushing more back than up until it isn't pushing up at all.
Seems like a really nice demonstration of fluid viscosity, cohesion, and surface tension to me. Place the spoon a few inches under the water in a stream and it becomes a better model of airflow around a wing.
Nice video Andre and nice that you brought up Newtons 3rd law but ..... :) It's Newton's 2nd law that actually describes 85% of the lift (15% of lift due to Bernoulli) The air is accelerated around a curved surface (flow turning) creating a centrifugal force which in turn throws the air outward creating the pressure differential and thus lift :) This effect is true for both top and bottom but two thirds of the lift is generated above the because the curve doesn't change directions unlike the bottom where the airflow "S"'s slightly but the air flow still averages a downward curve, plus the air is moving slower thus less energy in the centrifugal forces. Raw deflection of the air contributes very little to the lift component but plenty for the drag. There's more but that's the simple but accurate version of what's going on with a wing.
@freezatron Could you give some references for this? It's not a theory I've come across before, particularly the centrifugal forces. I'd like to read more.
That's because most people taught Bernoulli's theorem and then it's you don't need to know the rest etc. ...interestingly this is how the Coanda effect works too, similar deal why the low pressure is in the centre of the tornado, the air is being flung out by centrifugal force .... anyhow this video is very informative, I find this subject so fascinating :) ua-cam.com/video/QKCK4lJLQHU/v-deo.html
@@freezatron it's awesome that this is generating interesting discussion. I'm the first to admit that I'm not the most clued up on aerodynamics and it's great that people and chiming in to add/correct information. I'll have to find time (maybe in December) to watch that video. For those that have an even harder time than me understanding flow around the wing, the basic idea I wanted to stick with them is that air goes one way and the wing goes the other way :)
And as basic descriptions go yours is among the closest I've seen ;) A few more details and you're there mate :D :D :D The important bit to remember is that most of the lift is generated by airflow accelerated along a curve which induces centrifugal force throwing the air away from above the wing hence the pressure drop. Easy :D :D :D
Short and sweet, the overlayed arrows help illustrate the point a lot, thank you!
Was saying to myself "there has to be more wind downward to support the glider weight if it's "balanced" " then you said the very same.
Theory of flight is one thing I understand quite well, but these videos explain it very well for those not so sure.
Nice work
well done on the animations!
Actually Bernoulli's principle is an application of Newton's laws for inviscid and incompressable fluids. So only wrong thing about the Bernoulli's priciple explanation is the principle is too abstract to visualize. You cannot guess which part has low pressure or higher velocity. However with good understanding of Coanda effect, everybody can visualize where the lift is and how the air moves.
Thanks for this video, this is a great help for people who starts paragliding and wants to learn the physics behind it.
Correct until you talked about Coanda effect, which has nothing at all to do with flow over an airfoil.
is this karq s into ???????
Great job explaining the principles! It's always really good to understand what's happening.
But I feel like the system you showed here might be a little complicated to use in practice, because it's not tied directly to the required inputs or the feedback you get from the wing. To use this system I feel like one needs to convert the knowledge into inputs, observe the wing accelerating, understand that the balance of air spilling downwards and upwards is distrubed in this way and then start thinking of putting the appropriate input. (Mind you, maybe your brain is wired better for this kind of thinking than mine is :D )
I use airspeed over the wing as the parameter to control indirectly. There are two things that influence it when ground handling: wing loading ie how much tension there is on the lines and angle of attack/drag from brake inputs and pulling A's (sorry for the obvious statement :P ). This way if the wing is pulls you less strongly you know that the airspeed is going to drop so you need to take a step back to keep the wing flying and adjust brakes.
The critical thing I think is getting a good feeling for the tension on the lines and tying your reactions to the feedback from the wing and not to your processed understanding of what is happening. This shortens the reaction time considerably. Also, there is usually a slight delay between the feeling on the lines and the reaction of the wing so this way you are ready to or already giving the right inputs before the wing starts moving in a new direction.
And another key advantage is that in a tricky situation like a rotory launch or something, you react with very little processing. Left side pulls too much - slow it down immediately by brake or moving your feet. Wing doesn't pull hard enough - the wind died down a little and you need to take a few steps back to bring it overhead.
This is just the way I found most effective to think about this, it might be different for other people.
Anyway, apologies for the long comment, great videos and keep them coming!
Apologies not accepted! Long comments are great and I think what you're saying makes a lot of sense. It's one thing rationalizing it when sitting at a computer, but when I'm actually groundhandling I think my thought process is very similar to what you described! A lot more tension based and "feeling". Thank you so much for sharing!
Good thing our human brains are simplly pattern recognition devices. We don´t need to know or understand the physics in order to practice practice practie! It´s only practice that will develop our nervous systems with the fast reaction time needed to get the desired results. Studying the physics is a super super fun way to geek out though!
To understand lift and drag intuitively try handling sheets of plywood in a stiff breeze. That's all there is to it really. The shape of the wing makes the lift / drag ratio better and affects the handling characteristics (changes in forces generated) at low or high angles of incidence (angle the air hits the surface).
Hold the plywood sheet, edge to the wind and it'll just pull back a bit and fall. Tilt the front edge up and the whole sheet will start pushing up. Keep tilting it and it'll start pushing more back than up until it isn't pushing up at all.
Water + spoon is an example of the Coanda effect.
similar process though, a fluid is being accelerated around a curve :)
Seems like a really nice demonstration of fluid viscosity, cohesion, and surface tension to me. Place the spoon a few inches under the water in a stream and it becomes a better model of airflow around a wing.
Nice video Andre and nice that you brought up Newtons 3rd law but ..... :)
It's Newton's 2nd law that actually describes 85% of the lift (15% of lift due to Bernoulli)
The air is accelerated around a curved surface (flow turning) creating a centrifugal force which in turn throws the air outward creating the pressure differential and thus lift :)
This effect is true for both top and bottom but two thirds of the lift is generated above the because the curve doesn't change directions unlike the bottom where the airflow "S"'s slightly but the air flow still averages a downward curve, plus the air is moving slower thus less energy in the centrifugal forces.
Raw deflection of the air contributes very little to the lift component but plenty for the drag.
There's more but that's the simple but accurate version of what's going on with a wing.
@freezatron Could you give some references for this? It's not a theory I've come across before, particularly the centrifugal forces. I'd like to read more.
That's because most people taught Bernoulli's theorem and then it's you don't need to know the rest etc. ...interestingly this is how the Coanda effect works too, similar deal why the low pressure is in the centre of the tornado, the air is being flung out by centrifugal force .... anyhow this video is very informative, I find this subject so fascinating :)
ua-cam.com/video/QKCK4lJLQHU/v-deo.html
@@freezatron it's awesome that this is generating interesting discussion. I'm the first to admit that I'm not the most clued up on aerodynamics and it's great that people and chiming in to add/correct information. I'll have to find time (maybe in December) to watch that video. For those that have an even harder time than me understanding flow around the wing, the basic idea I wanted to stick with them is that air goes one way and the wing goes the other way :)
And as basic descriptions go yours is among the closest I've seen ;)
A few more details and you're there mate :D :D :D
The important bit to remember is that most of the lift is generated by airflow accelerated along a curve which induces centrifugal force throwing the air away from above the wing hence the pressure drop.
Easy :D :D :D
@@freezatron The thing is when your wing is a mess, upside down with cravats and a bowtie in the middle, which line are you going to pull? xD