About wing lift
11-29-2002 | 03:25 PM
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From: e, ZIMBABWE
About wing lift
Did you also got fooled by some book or teacher about the theory of wing lift in the past?
They always say it is caused by the shape of the classic assymetric air-foil section.
For the first time ever, I saw some guy in T.V., telling some truth about it. Some guy sent a question about if the assymetrical airfoil is the cause of airplane wings providing lift, how come some airplanes can fly inverted ?
The answer is of cource this: Different airfoils is different optimazions for drag/lift ratio. Even a table or a reasonable flat stone can fly with sufficient speed and ANGLE OF ATTACK, the magic word.
The effect of AOA is easily studied when you are taking a bath, wave your hand in the water with different AOA.
I know I have limited knowledge about aerodynamics and this might look like a besserwisser thing but I really think this is important.
AOA and air speed causes air molecules of different kinds (N2, O2, Ar) hit the wing on the lower surface, causing a force on the wing, and what is attached to it, that can be divided in two resultants: induced drag and lift.
Assymetrical airfoils produces same amount of lift at lower angles of attack, even negative angles. This is important for aircrafts that has to fly economical, slowl or with a weak engine, its about optimizion.
Sometimes, its said that the low pressure on the upper side of the wing causes more lift than the high pressure on the lower side.
This is just a riddling with words or something.
Low pressure can not ever produce mechanical work.
It's always the relative higher pressure located somewhere that produces work.
The word "pressure" is expressing how hard gas atoms/ molecules are hammering on a surface or eachother. This hammering is caused by the movement induced by temperature and/or relative speed to some obstacle like a wing surface or two gas streams hitting eachother.
Pressure can be divided into static and dynamic pressure, The first caused by temperature, the latter by relative difference in speed.
Pressure meashured on different locations at lower and upper surface of a wing, should be compared to eachother, not with surrounding pressure.
If I am wrong, the extremely low pressure in outer space should provide a vaste source of energy for ISS and other space ships [img]i/expressions/face-icon-small-happy.gif[/img] Why cannot this vaccuum suck a space ship to Mars without using LH/LOX and stuff [img]i/expressions/face-icon-small-happy.gif[/img]
/Bo
They always say it is caused by the shape of the classic assymetric air-foil section.
For the first time ever, I saw some guy in T.V., telling some truth about it. Some guy sent a question about if the assymetrical airfoil is the cause of airplane wings providing lift, how come some airplanes can fly inverted ?
The answer is of cource this: Different airfoils is different optimazions for drag/lift ratio. Even a table or a reasonable flat stone can fly with sufficient speed and ANGLE OF ATTACK, the magic word.
The effect of AOA is easily studied when you are taking a bath, wave your hand in the water with different AOA.
I know I have limited knowledge about aerodynamics and this might look like a besserwisser thing but I really think this is important.
AOA and air speed causes air molecules of different kinds (N2, O2, Ar) hit the wing on the lower surface, causing a force on the wing, and what is attached to it, that can be divided in two resultants: induced drag and lift.
Assymetrical airfoils produces same amount of lift at lower angles of attack, even negative angles. This is important for aircrafts that has to fly economical, slowl or with a weak engine, its about optimizion.
Sometimes, its said that the low pressure on the upper side of the wing causes more lift than the high pressure on the lower side.
This is just a riddling with words or something.
Low pressure can not ever produce mechanical work.
It's always the relative higher pressure located somewhere that produces work.
The word "pressure" is expressing how hard gas atoms/ molecules are hammering on a surface or eachother. This hammering is caused by the movement induced by temperature and/or relative speed to some obstacle like a wing surface or two gas streams hitting eachother.
Pressure can be divided into static and dynamic pressure, The first caused by temperature, the latter by relative difference in speed.
Pressure meashured on different locations at lower and upper surface of a wing, should be compared to eachother, not with surrounding pressure.
If I am wrong, the extremely low pressure in outer space should provide a vaste source of energy for ISS and other space ships [img]i/expressions/face-icon-small-happy.gif[/img] Why cannot this vaccuum suck a space ship to Mars without using LH/LOX and stuff [img]i/expressions/face-icon-small-happy.gif[/img]
/Bo
11-30-2002 | 12:28 PM
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From: MD
About wing lift
Check this out:
http://www.lerc.nasa.gov/WWW/K-12/airplane/right2.html
Also has comments on some other theories (look in the index under lift)
http://www.lerc.nasa.gov/WWW/K-12/airplane/right2.html
Also has comments on some other theories (look in the index under lift)
11-30-2002 | 11:03 PM
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From: gone,
About wing lift
The mixed up mess above, is just going to confuse a lot of people, as it says just enough to cause confusion, not enough to clear ANYTHING up. If it were presented properly... it would take about 600 k of ASCII text. (2 k is one double-spaced typewritten page)
The normal simplified explaination of how a wing produces lift is adequate for a basic understanding of flight. We present the simplified Bernouli explaination for the purpose of explaining that you need AIRSPEED to have the wing "create" lift. Inadequate airspeed and/or excess angle of attack means the plane falls out of the sky. (when the wing stalls)
The extra details, which are not needed to give a basic explaination of how a wing works, are ignored when using a flat bottom, high lift airfoil as the introductory example of how a wing holds a plane in the air. This common practice is not an intentional deception... its just an attempt to not overload a beginning R/C pilot with unnecessary information.
You want a PARTIAL explaination of what's missing? Go to: http://www.allstar.fiu.edu/aero/airflylvl3.htm
The full description of how a wing works takes the average Aeronautical Engineering student a couple of years to get right...
The normal simplified explaination of how a wing produces lift is adequate for a basic understanding of flight. We present the simplified Bernouli explaination for the purpose of explaining that you need AIRSPEED to have the wing "create" lift. Inadequate airspeed and/or excess angle of attack means the plane falls out of the sky. (when the wing stalls)
The extra details, which are not needed to give a basic explaination of how a wing works, are ignored when using a flat bottom, high lift airfoil as the introductory example of how a wing holds a plane in the air. This common practice is not an intentional deception... its just an attempt to not overload a beginning R/C pilot with unnecessary information.
You want a PARTIAL explaination of what's missing? Go to: http://www.allstar.fiu.edu/aero/airflylvl3.htm
The full description of how a wing works takes the average Aeronautical Engineering student a couple of years to get right...
11-30-2002 | 11:17 PM
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From: e, ZIMBABWE
About wing lift
I apologize, Huber.
My first language is not English, hence the mess.
I hope My English is better than your Swedish. [img]i/expressions/face-icon-small-tongue.gif[/img]
Sorry.
/Bo
My first language is not English, hence the mess.
I hope My English is better than your Swedish. [img]i/expressions/face-icon-small-tongue.gif[/img]
Sorry.
/Bo
12-03-2002 | 02:28 PM
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From: Frederick, MD
Some thoughts from a rocket scientist...
What a mess.... The pressure differential between the top and the bottom of the airfoil causes lift. Period, end of discussion.
Many things can influence the pressure distribution on an (2D) airfoil including: geometry, air density, angle of attack, and velocity.
To further complicate things the actual lift produced is determined by the (3D) wing. Some of the factors include: aspect ratio, shape, lift distribution, etc.
Many things can influence the pressure distribution on an (2D) airfoil including: geometry, air density, angle of attack, and velocity.
To further complicate things the actual lift produced is determined by the (3D) wing. Some of the factors include: aspect ratio, shape, lift distribution, etc.
