Random facts about planes..
Discussion
AVV EM said:
Due to the shape of a wing, the air going over it is slowed down, slower than the air passing under it. This produces a pressure differential between the top and bottom of the wing. The top surface being of a lower pressure than the underside therefor the wing is sucked upwards by the lower pressure. Hence why its the top of a wing that produces lift, not the bottom.
The NASA link is correct (obvs), but the Bernoulli explanation above relates to the air going over the wing accelerating and not slowing down.Nah, it's all about Bernoullis.
The engines produce Bernoullis and it is these that magically make the a/c fly.
Of course, in the case of engineless a/c such as gliders, what you have to do is pump the fuselage full of Bernoullis such that the glider will fly. Given that the glider is not sealed the Bernoullis gradually leak out so the glider returns to earth.
At least, that's how we always explained the miracle of flight to the Pongoes...
The engines produce Bernoullis and it is these that magically make the a/c fly.
Of course, in the case of engineless a/c such as gliders, what you have to do is pump the fuselage full of Bernoullis such that the glider will fly. Given that the glider is not sealed the Bernoullis gradually leak out so the glider returns to earth.
At least, that's how we always explained the miracle of flight to the Pongoes...
AVV EM said:
Due to the shape of a wing, the air going over it is slowed down, slower than the air passing under it. This produces a pressure differential between the top and bottom of the wing. The top surface being of a lower pressure than the underside therefor the wing is sucked upwards by the lower pressure. Hence why its the top of a wing that produces lift, not the bottom.
You've got that the wrong way round. Faster moving air is lower pressure air. Due to the aerofoil shape of the wing section, the air that flows over the wing has to travel faster than the air below it, as it has a greater distance to travel. That's what creates the pressure difference between the lower and upper surfaces of the wing, and hence lift.amongst other forms, "lift" can be created by "skipping" across the surface of a higher density fluid like a stone over water (space re-entry vehicles), and through forced flow direction changes. Basically forcing a fluid to move in a different direction will create an equal and opposite force. E.g a fan, or a crude non aerofoil section wing, or very simply something being blown by the wind
dvs_dave said:
You've got that the wrong way round. Faster moving air is lower pressure air. Due to the aerofoil shape of the wing section, the air that flows over the wing has to travel faster than the air below it, as it has a greater distance to travel. That's what creates the pressure difference between the lower and upper surfaces of the wing, and hence lift.
Woops, my bad, AVV EM said:
dvs_dave said:
You've got that the wrong way round. Faster moving air is lower pressure air. Due to the aerofoil shape of the wing section, the air that flows over the wing has to travel faster than the air below it, as it has a greater distance to travel. That's what creates the pressure difference between the lower and upper surfaces of the wing, and hence lift.
Woops, my bad, To be fair, that is kind of how how most people thought wings worked until comparatively recently.
But it is not.
If it were, an aircraft would not be able to fly inverted.
Ayahuasca said:
AVV EM said:
dvs_dave said:
You've got that the wrong way round. Faster moving air is lower pressure air. Due to the aerofoil shape of the wing section, the air that flows over the wing has to travel faster than the air below it, as it has a greater distance to travel. That's what creates the pressure difference between the lower and upper surfaces of the wing, and hence lift.
Woops, my bad, To be fair, that is kind of how how most people thought wings worked until comparatively recently.
But it is not.
If it were, an aircraft would not be able to fly inverted.
And coincidentally on topic.
http://www.telegraph.co.uk/news/science/science-ne...
Eric - Re the blowing over the top of paper making it rise. You honestly think there is any comparison regarding the difference in velocity between the slightly longer path over curved surface, vs 100x the difference in speed by blowing across a flat surface over the stationary air below?
http://www.telegraph.co.uk/news/science/science-ne...
Eric - Re the blowing over the top of paper making it rise. You honestly think there is any comparison regarding the difference in velocity between the slightly longer path over curved surface, vs 100x the difference in speed by blowing across a flat surface over the stationary air below?
Brother D said:
And coincidentally on topic.
http://www.telegraph.co.uk/news/science/science-ne...
Eric - Re the blowing over the top of paper making it rise. You honestly think there is any comparison regarding the difference in velocity between the slightly longer path over curved surface, vs 100x the difference in speed by blowing across a flat surface over the stationary air below?
I'm not stating or claiming anything - just that such little experiments are often used to demonstrate the principle of how differing pressures on either side of a sheet cause it to move towards the faster flowing airflow.http://www.telegraph.co.uk/news/science/science-ne...
Eric - Re the blowing over the top of paper making it rise. You honestly think there is any comparison regarding the difference in velocity between the slightly longer path over curved surface, vs 100x the difference in speed by blowing across a flat surface over the stationary air below?
I've no idea how relevant they are to how an actual aircraft wing (or any other shape that can be used to create lift) actually works.
I found the NASA pages a bit awkward to navigate, but did find this which may be of interest; titled 'How Airplanes Fly': http://www.allstar.fiu.edu/aero/airflylvl3.htm
edit: there is an updated of the article here: http://www.allstar.fiu.edu/aero/Flightrevisited.pd...
edit: there is an updated of the article here: http://www.allstar.fiu.edu/aero/Flightrevisited.pd...
Edited by gregs656 on Friday 21st April 09:48
thebraketester said:
100% true.
Same as magnets. No one know how they work either.
Magnets work due to special relativity.Same as magnets. No one know how they work either.
https://www.youtube.com/watch?v=1TKSfAkWWN0
Again, nice theory, but then outside of the world of maths, every reason for why something works or not is a "theory".
So if you accept the theory then one does not have to deal with black & white 'fact'
You only have to worry about a superseding theory that matches prediction and measurement more accurately.
It is indeed because of Bernoulli's Principle. Simply put, there is a relationship between pressure, velocity and fluid density.
Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
Alias218 said:
It is indeed because of Bernoulli's Principle. Simply put, there is a relationship between pressure, velocity and fluid density.
Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
Except that aircraft can fly upside down. The Bernoulli principle is a minor effect and some wings have upper surfaces the same length as the lower. Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
Stick a hand out of the window of a moving car palm down. Twist your wrist so the airflow hits the palm and you have lift, twist it the other way and it's pushed down, no need for Bernoulli.
A better example of Bernoulli in action is toilet bowls.
Dr Jekyll said:
Alias218 said:
It is indeed because of Bernoulli's Principle. Simply put, there is a relationship between pressure, velocity and fluid density.
Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
Except that aircraft can fly upside down. The Bernoulli principle is a minor effect and some wings have upper surfaces the same length as the lower. Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
Stick a hand out of the window of a moving car palm down. Twist your wrist so the airflow hits the palm and you have lift, twist it the other way and it's pushed down, no need for Bernoulli.
A better example of Bernoulli in action is toilet bowls.
Alias218 said:
It is indeed because of Bernoulli's Principle. Simply put, there is a relationship between pressure, velocity and fluid density.
Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
Take a look at an aerofoil cross section for a fast jet, or a simple foam glider and report back. Amazed at the number of posters on here who still believe this.Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
LimaDelta said:
Alias218 said:
It is indeed because of Bernoulli's Principle. Simply put, there is a relationship between pressure, velocity and fluid density.
Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
Take a look at an aerofoil cross section for a fast jet, or a simple foam glider and report back. Amazed at the number of posters on here who still believe this.Taking fluid density (rho p) to be constant (in this instance air) then an increase in velocity results in a decrease in pressure. On an airfoil, the upper surface is longer than the bottom surface, resulting in two different velocities (due to the greater distance the body of air has to travel relative to the underside of the airfoil) and ultimately a pressure differential is formed as per Bernoulli's equation.
As a consequence, the pressure is lower above the wing than that below this creating lift. Turn a wing upside down and you have a spoiler! Same principle, but tipped arse over tit. It's also how carburettors work.
Other factors are in play like boundary layers and laminar/turbulent airflow but that's the bones of it, although I've probably left out the nuances of it.
Personally, it's my favourite principle owing to its simplicity and far reaching applications!
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