my take on wings
12-04-2010, 09:43 PM
#26
RE: my take on wings
ORIGINAL: rmh
The flat plate is not for the man carrying stuf but works extremely well in setups with low wing loadings
for example a 6 ounce model with 275 square inches.
One can fritter away time trying for a better setup on aerobats of this size but gain nothing in performance. The advent of really efficient electric power setups (very light weight and powerful) plus foamed plastics which are strong yet compliant enough to not break easily, have made possible -instant cut n try engineering.
The results have proven to be excellent in that the cost and time involved from idea to actual use is in minutes - not weeks.
The flat plate is not for the man carrying stuf but works extremely well in setups with low wing loadings
for example a 6 ounce model with 275 square inches.
One can fritter away time trying for a better setup on aerobats of this size but gain nothing in performance. The advent of really efficient electric power setups (very light weight and powerful) plus foamed plastics which are strong yet compliant enough to not break easily, have made possible -instant cut n try engineering.
The results have proven to be excellent in that the cost and time involved from idea to actual use is in minutes - not weeks.
Check this "flatfoil" performance out:
http://www.nanoplanes.net/bshark.html
12-05-2010, 12:08 AM
#27
RE: my take on wings
ORIGINAL: Lnewqban
Enough power to weight ratios can produce amazing results.
Check this ''flatfoil'' performance out:
http://www.nanoplanes.net/bshark.html
Enough power to weight ratios can produce amazing results.
Check this ''flatfoil'' performance out:
http://www.nanoplanes.net/bshark.html
Usual university research seems to be about better airfoils but not about such basic practical questions. There's no interest and no funding for that.
12-05-2010, 04:55 AM
#28
RE: my take on wings
The Kwick Fly Dance had a simple fix.
The cause was the location of the plastic canopy.
Change the canopy or eliminate it and the "dance "went away
I tried this on miine and it worked
Also I learned how to generate the dance in similar models, through an unexpected problem at a fun fly event.
My model (it was in 1974) was a typical box fuselage type, to which I added a paper cup just forward the canopy.
The cup held an egg for the egg drop.
the model danced shortly after take off -
Moving the cup eliminated the problem
The disturbed air from th cup location, greatly reduced rudder efficiency and the tail simply established a harmonic wag
The cause was the location of the plastic canopy.
Change the canopy or eliminate it and the "dance "went away
I tried this on miine and it worked
Also I learned how to generate the dance in similar models, through an unexpected problem at a fun fly event.
My model (it was in 1974) was a typical box fuselage type, to which I added a paper cup just forward the canopy.
The cup held an egg for the egg drop.
the model danced shortly after take off -
Moving the cup eliminated the problem
The disturbed air from th cup location, greatly reduced rudder efficiency and the tail simply established a harmonic wag
12-05-2010, 02:15 PM
#30
Moderator
RE: my take on wings
Even a flat plate is an airfoil. It has thickness, and the airflow does accelerate more over the top of it than the bottom. With a rounded leading edge, the boundary layer stays on fairly well at low angles of attack. But even with a squared or sharp leading edge the acceleration and pressure drop still occurs, even though the critical stall angle is so low that the practical lift produced is fairly low. For the OP, if you really think it's mostly about air deflection off the bottom of the wing, then pull the covering off the top and see what happens. Many of the early designs essentially had a top but no bottom because testing showed that it's airflow over the top of a curved surface that produces enough practical lift to make airplanes possible.
12-05-2010, 03:13 PM
#31
RE: my take on wings
actually-there was a top and bottom just a verrrrry thin wing
anything which is non porous will provide a chance for pressure differences -and that is what makes it all work.
There have ben endless writings about downwash , hogwash, etc., but when the final verdict is in it's all about pressure differences. The shapes used simply change the efficiency.
We all tend to overcomplicate "what makes it fly".
Basic rules :
Ifn it's light enough - nothing else matters
Ifn its too heavy there is no fixn it
Ifn you make it go fast enough anything will fly
Ifn it stops movin fast enough-it's through flying
anything which is non porous will provide a chance for pressure differences -and that is what makes it all work.
There have ben endless writings about downwash , hogwash, etc., but when the final verdict is in it's all about pressure differences. The shapes used simply change the efficiency.
We all tend to overcomplicate "what makes it fly".
Basic rules :
Ifn it's light enough - nothing else matters
Ifn its too heavy there is no fixn it
Ifn you make it go fast enough anything will fly
Ifn it stops movin fast enough-it's through flying
12-06-2010, 06:01 AM
#32
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RE: my take on wings
Newtons second law of motion states that Force=Mass X acceleration.
If you sit at the end of a runway all day long as a kid, you get that law used on you with every big plane that goes over you. The downwash of a 747 is just not to be believed until you experience it.
So how much sucking would it take to hold a 500 ton A380 off of the ground using Bernoulli?
http://www.amasci.com/wing/airfoil.html
Quite a bit I think. But that low pressure area above the wing is of great importance, because it helps get a Mass of air moving around the wing. Up and over the top and down at the rear. It is the acceleration of this Mass of air in the downward direction that supports the plane.
Notice that the drooped leading edges move down and scoop more air in afront view that must thenmove over the top of the wing. This air acceleratesreducing its pressure andassisting in lift but only a small amount. Perhaps 15%
of the total. Notice the tripple slotted fowler flaps hanging down into the airstream, the last onecan be at more than 50 degrees in some aircraft. On the F-4 Fantom the plain flaps go down to nearly 90 degrees. N-2 compressorair is blown down the back of the flaps and from the back of the drooped leading edges to keep Bernoulli flow attached to the wing and flaps without regardto airspeed. So a 74,000 fighter can float back aboard like a Piper cub instead of a freight train.
Notice that real aiplane airfoils have a zero lift line. This is a line that represents the nose down attitude when airflow inducedlift is in ballance on top and bottom and the airfoil is producing zero lift and zero downforce.
http://www.grc.nasa.gov/WWW/K-12/airplane/foil2.html
Download Foilsim and build any number of airfoils and watch the performance. Itsfree sort of. Your taxes paid for it.
Here for basic understanding and nomenclature.http://www.infouse.com/planemath/act...s_teacher.html
The rest of the lift is just the angle of attack. You might say that it is a Dynamic form of lift. Like you hand out the car window. Would you build a wing that looks like you hand? Yet it seems to work at 60 MPH.
During the design of the A-4 Skyhawk by Douglass, a young engineer was assigned to pick the most effective airfoil.
He spent a month collecting data on every known airfoil and sorting out the peak performance of each in the hope of developing the PERFECT airfoil for the project. The chief engineer looked at the outcome and told the young fellow to calculate it again using two sheets of 3/4" plywood laminated together. Dumbfounded, the young guy returned in a few hours to report that performance would be off by about 4%.
Most airfoils are stalled by 14 degrees of angle of attack. So the flow separation reduces the amount of air rotating around the upper surface, and the downwash is reduced, so a loss of lift is suffered. A loss but not all.
A real snap roll is performed with the stick centered but pulled back all of the way (Stalling the wing) and the rudder hard over against the stops. So, a snap roll is a flat spin performed in the horizontal. So it matters not at all what the ailerons look like.
Google Coanda Effect.
Lynn E. Hanover
If you sit at the end of a runway all day long as a kid, you get that law used on you with every big plane that goes over you. The downwash of a 747 is just not to be believed until you experience it.
So how much sucking would it take to hold a 500 ton A380 off of the ground using Bernoulli?
http://www.amasci.com/wing/airfoil.html
Quite a bit I think. But that low pressure area above the wing is of great importance, because it helps get a Mass of air moving around the wing. Up and over the top and down at the rear. It is the acceleration of this Mass of air in the downward direction that supports the plane.
Notice that the drooped leading edges move down and scoop more air in afront view that must thenmove over the top of the wing. This air acceleratesreducing its pressure andassisting in lift but only a small amount. Perhaps 15%
of the total. Notice the tripple slotted fowler flaps hanging down into the airstream, the last onecan be at more than 50 degrees in some aircraft. On the F-4 Fantom the plain flaps go down to nearly 90 degrees. N-2 compressorair is blown down the back of the flaps and from the back of the drooped leading edges to keep Bernoulli flow attached to the wing and flaps without regardto airspeed. So a 74,000 fighter can float back aboard like a Piper cub instead of a freight train.
Notice that real aiplane airfoils have a zero lift line. This is a line that represents the nose down attitude when airflow inducedlift is in ballance on top and bottom and the airfoil is producing zero lift and zero downforce.
http://www.grc.nasa.gov/WWW/K-12/airplane/foil2.html
Download Foilsim and build any number of airfoils and watch the performance. Itsfree sort of. Your taxes paid for it.
Here for basic understanding and nomenclature.http://www.infouse.com/planemath/act...s_teacher.html
The rest of the lift is just the angle of attack. You might say that it is a Dynamic form of lift. Like you hand out the car window. Would you build a wing that looks like you hand? Yet it seems to work at 60 MPH.
During the design of the A-4 Skyhawk by Douglass, a young engineer was assigned to pick the most effective airfoil.
He spent a month collecting data on every known airfoil and sorting out the peak performance of each in the hope of developing the PERFECT airfoil for the project. The chief engineer looked at the outcome and told the young fellow to calculate it again using two sheets of 3/4" plywood laminated together. Dumbfounded, the young guy returned in a few hours to report that performance would be off by about 4%.
Most airfoils are stalled by 14 degrees of angle of attack. So the flow separation reduces the amount of air rotating around the upper surface, and the downwash is reduced, so a loss of lift is suffered. A loss but not all.
A real snap roll is performed with the stick centered but pulled back all of the way (Stalling the wing) and the rudder hard over against the stops. So, a snap roll is a flat spin performed in the horizontal. So it matters not at all what the ailerons look like.
Google Coanda Effect.
Lynn E. Hanover
12-06-2010, 07:33 AM
#33
RE: my take on wings
ORIGINAL: lehanover
.
e that real aiplane airfoils have a zero lift line. This is a line that represents the nose down attitude when airflow induced lift is in ballance on top and bottom and the airfoil is producing zero lift and zero downforce.
<Lynn E. Hanover
.
e that real aiplane airfoils have a zero lift line. This is a line that represents the nose down attitude when airflow induced lift is in ballance on top and bottom and the airfoil is producing zero lift and zero downforce.
<Lynn E. Hanover
Really high performance aerobatic stuff use fully symm shapes and change AOA as needed.
Shape is related to desired efficiency for the task at hand
.
12-07-2010, 09:12 PM
#34
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RE: my take on wings
ORIGINAL: lehanover
Newtons second law of motion states that Force=Mass X acceleration.
If you sit at the end of a runway all day long as a kid, you get that law used on you with every big plane that goes over you. The downwash of a 747 is just not to be believed until you experience it.
So how much sucking would it take to hold a 500 ton A380 off of the ground using Bernoulli?
http://www.amasci.com/wing/airfoil.html
Quite a bit I think. But that low pressure area above the wing is of great importance, because it helps get a Mass of air moving around the wing. Up and over the top and down at the rear. It is the acceleration of this Mass of air in the downward direction that supports the plane.
Notice that the drooped leading edges move down and scoop more air in a front view that must then move over the top of the wing. This air accelerates reducing its pressure and assisting in lift but only a small amount. Perhaps 15%
of the total. Notice the tripple slotted fowler flaps hanging down into the airstream, the last one can be at more than 50 degrees in some aircraft. On the F-4 Fantom the plain flaps go down to nearly 90 degrees. N-2 compressor air is blown down the back of the flaps and from the back of the drooped leading edges to keep Bernoulli flow attached to the wing and flaps without regard to airspeed. So a 74,000 fighter can float back aboard like a Piper cub instead of a freight train.
Notice that real aiplane airfoils have a zero lift line. This is a line that represents the nose down attitude when airflow induced lift is in ballance on top and bottom and the airfoil is producing zero lift and zero downforce.
http://www.grc.nasa.gov/WWW/K-12/airplane/foil2.html
Download Foilsim and build any number of airfoils and watch the performance. Its free sort of. Your taxes paid for it.
Here for basic understanding and nomenclature. http://www.infouse.com/planemath/act...s_teacher.html
The rest of the lift is just the angle of attack. You might say that it is a Dynamic form of lift. Like you hand out the car window. Would you build a wing that looks like you hand? Yet it seems to work at 60 MPH.
During the design of the A-4 Skyhawk by Douglass, a young engineer was assigned to pick the most effective airfoil.
He spent a month collecting data on every known airfoil and sorting out the peak performance of each in the hope of developing the PERFECT airfoil for the project. The chief engineer looked at the outcome and told the young fellow to calculate it again using two sheets of 3/4'' plywood laminated together. Dumbfounded, the young guy returned in a few hours to report that performance would be off by about 4%.
Most airfoils are stalled by 14 degrees of angle of attack. So the flow separation reduces the amount of air rotating around the upper surface, and the downwash is reduced, so a loss of lift is suffered. A loss but not all.
A real snap roll is performed with the stick centered but pulled back all of the way (Stalling the wing) and the rudder hard over against the stops. So, a snap roll is a flat spin performed in the horizontal. So it matters not at all what the ailerons look like.
Google Coanda Effect.
Lynn E. Hanover
Newtons second law of motion states that Force=Mass X acceleration.
If you sit at the end of a runway all day long as a kid, you get that law used on you with every big plane that goes over you. The downwash of a 747 is just not to be believed until you experience it.
So how much sucking would it take to hold a 500 ton A380 off of the ground using Bernoulli?
http://www.amasci.com/wing/airfoil.html
Quite a bit I think. But that low pressure area above the wing is of great importance, because it helps get a Mass of air moving around the wing. Up and over the top and down at the rear. It is the acceleration of this Mass of air in the downward direction that supports the plane.
Notice that the drooped leading edges move down and scoop more air in a front view that must then move over the top of the wing. This air accelerates reducing its pressure and assisting in lift but only a small amount. Perhaps 15%
of the total. Notice the tripple slotted fowler flaps hanging down into the airstream, the last one can be at more than 50 degrees in some aircraft. On the F-4 Fantom the plain flaps go down to nearly 90 degrees. N-2 compressor air is blown down the back of the flaps and from the back of the drooped leading edges to keep Bernoulli flow attached to the wing and flaps without regard to airspeed. So a 74,000 fighter can float back aboard like a Piper cub instead of a freight train.
Notice that real aiplane airfoils have a zero lift line. This is a line that represents the nose down attitude when airflow induced lift is in ballance on top and bottom and the airfoil is producing zero lift and zero downforce.
http://www.grc.nasa.gov/WWW/K-12/airplane/foil2.html
Download Foilsim and build any number of airfoils and watch the performance. Its free sort of. Your taxes paid for it.
Here for basic understanding and nomenclature. http://www.infouse.com/planemath/act...s_teacher.html
The rest of the lift is just the angle of attack. You might say that it is a Dynamic form of lift. Like you hand out the car window. Would you build a wing that looks like you hand? Yet it seems to work at 60 MPH.
During the design of the A-4 Skyhawk by Douglass, a young engineer was assigned to pick the most effective airfoil.
He spent a month collecting data on every known airfoil and sorting out the peak performance of each in the hope of developing the PERFECT airfoil for the project. The chief engineer looked at the outcome and told the young fellow to calculate it again using two sheets of 3/4'' plywood laminated together. Dumbfounded, the young guy returned in a few hours to report that performance would be off by about 4%.
Most airfoils are stalled by 14 degrees of angle of attack. So the flow separation reduces the amount of air rotating around the upper surface, and the downwash is reduced, so a loss of lift is suffered. A loss but not all.
A real snap roll is performed with the stick centered but pulled back all of the way (Stalling the wing) and the rudder hard over against the stops. So, a snap roll is a flat spin performed in the horizontal. So it matters not at all what the ailerons look like.
Google Coanda Effect.
Lynn E. Hanover
banktoturn
12-08-2010, 04:00 AM
#35
RE: my take on wings
I think many are try to understand the side effects and the methods for increasing efficiency.
pressure difference is-of course the basic reason-for flight and the weather .
pressure difference is-of course the basic reason-for flight and the weather .
12-08-2010, 04:52 AM
#36
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RE: my take on wings
The various airfoil shapes, even the flat ones like sheets of plywood, need only alter airflow into a vector in the downward direction. Like a pool ball off a bank shot. So, the flat wing glider, although not very efficient can perform well for its weight. It does generate rotation just as a fully developed airfoil. It does generate a downwash, just not much.
Bernoulli explains the higher velocity of air over the top. Coanda explains the rotation, and Newton tells us how many tons of air per second displaced downward and at what vector is required for level flight.
Nobody picks anything. Now downwash = no flight.
Mother Nature's rules, not mine.
Lynn E. Hanover
Bernoulli explains the higher velocity of air over the top. Coanda explains the rotation, and Newton tells us how many tons of air per second displaced downward and at what vector is required for level flight.
Nobody picks anything. Now downwash = no flight.
Mother Nature's rules, not mine.
Lynn E. Hanover
12-08-2010, 05:21 AM
#37
RE: my take on wings
Some aerodynamics which are interesting -to me.
We have a number of mountains in our area and the winds change quite predictably as the temperature changes during a day
In a few areas there are very solid updrafts much of the time -which are used by hang gliders and model glider guys.
If you look at the flows - you can see how the pressures follow around or thru the hills and valleys
Just like air flows around a wing/fuselage etc..
Those living near the canyons , see this effect daily.
We have a number of mountains in our area and the winds change quite predictably as the temperature changes during a day
In a few areas there are very solid updrafts much of the time -which are used by hang gliders and model glider guys.
If you look at the flows - you can see how the pressures follow around or thru the hills and valleys
Just like air flows around a wing/fuselage etc..
Those living near the canyons , see this effect daily.
12-08-2010, 07:08 AM
#38
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RE: my take on wings
ORIGINAL: lehanover
The various airfoil shapes, even the flat ones like sheets of plywood, need only alter airflow into a vector in the downward direction. Like a pool ball off a bank shot. So, the flat wing glider, although not very efficient can perform well for its weight. It does generate rotation just as a fully developed airfoil. It does generate a downwash, just not much.
Bernoulli explains the higher velocity of air over the top. Coanda explains the rotation, and Newton tells us how many tons of air per second displaced downward and at what vector is required for level flight.
Nobody picks anything. Now downwash = no flight.
Mother Nature's rules, not mine.
Lynn E. Hanover
The various airfoil shapes, even the flat ones like sheets of plywood, need only alter airflow into a vector in the downward direction. Like a pool ball off a bank shot. So, the flat wing glider, although not very efficient can perform well for its weight. It does generate rotation just as a fully developed airfoil. It does generate a downwash, just not much.
Bernoulli explains the higher velocity of air over the top. Coanda explains the rotation, and Newton tells us how many tons of air per second displaced downward and at what vector is required for level flight.
Nobody picks anything. Now downwash = no flight.
Mother Nature's rules, not mine.
Lynn E. Hanover
"No Downwash=no flight" is correct. So are these: No pressure difference=no downwash, no circulation=no downwash, no circulation=no pressure difference, no viscosity=no lift, ... Choosing any of these as more important or separate from the others is meaningless and incorrect.
banktoturn
12-08-2010, 07:23 AM
#39
RE: my take on wings
.........and here are the formulas that try to take everything into consideration:
http://www.grc.nasa.gov/WWW/K-12/airplane/nseqs.html
http://www.grc.nasa.gov/WWW/K-12/airplane/nseqs.html
12-09-2010, 03:01 PM
#40
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RE: my take on wings
Lehanover and B2T, I'm not sure from the replies to each other if you're teaming up or disagreeing. But from where I'm reading it looks like you're both in total agreement and are "tag teaming" at slam dunking the same information onto us...
B2T, haven't seen you posting in some time. It's nice to have you back again.
B2T, haven't seen you posting in some time. It's nice to have you back again.
12-11-2010, 06:29 PM
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RE: my take on wings
I have to agree with BankToTurn. It is possible to accurately "decompose" lift into a component that is due to surface pressures that are below ambient atmospheric pressure (suction) and a component due to surface pressures that are above atmospheric pressure. However, It is NOT possible to accurately decompose lift into a compotent due to surface pressures and a component due to momentum transfer ("Newton" or "F=ma"). The two phenomena are both at work, but they are inextricably connected. Depending on your perspective, the surface pressures cause the momentum transfer or the momentum transfer causes the surface pressures.
Looking at a slightly difeerent problem, You can sum up all of the momentum leaving a rocket engine and figure out the engine's thrust. You can also sum up all of the pressures acting on the surface of the rocket engine to figure out it's thrust. Either method will give the same answer. It's not that some of the thrust is coming from momentum and some from pressure. The fact that you can attribute ALL of the thrust to momentum transfer or ALL of the thrust to surface pressures is not a contradiction. Newton's 2nd law establishes the connection between the two... You can't have one without the other.
Looking at a slightly difeerent problem, You can sum up all of the momentum leaving a rocket engine and figure out the engine's thrust. You can also sum up all of the pressures acting on the surface of the rocket engine to figure out it's thrust. Either method will give the same answer. It's not that some of the thrust is coming from momentum and some from pressure. The fact that you can attribute ALL of the thrust to momentum transfer or ALL of the thrust to surface pressures is not a contradiction. Newton's 2nd law establishes the connection between the two... You can't have one without the other.
12-13-2010, 07:25 AM
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RE: my take on wings
Hi BMatthews,
Mostly, I think I'm disagreeing with Lehanover; sorry I wasn't clear. The day job seems to fill most of my hours, but I try to stop by once in a while, thanks.
Hi Shoe,
Nicely put; I think you captured it very well with the rocket explanation.
banktoturn
12-19-2010, 11:32 AM
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RE: my take on wings
Bernoulli Sucks
A wing changes the position of air molecules - each molecule has mass.
For every action there is an equal and oppositie REACTION..
Pushing air down will create a reaction on the wing UPWARDS...
It always amazes me how people can think lift is produced due to the LOWER pressure on the upper surface of the wing..
HOW does that EXPLAIN the Incredible DOWNWASH from a helicopter when it is hovering - have you tried standing under a hovering helicopter? - Good luck!
Or how does it explain the PROPELLER wash that will BLOW a person OVER if you stand behind even a light aircraft at full throttle..
The Wing / Rotor and Propellor DEFLECT air molecules and the lift or Thrust created is the equal and opposite reaction...
VERY SIMPLE Physics
12-20-2010, 09:55 PM
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RE: my take on wings
HOW does that EXPLAIN the Incredible DOWNWASH from a helicopter when it is hovering - have you tried standing under a hovering helicopter? - Good luck!
12-21-2010, 09:42 AM
#46
RE: my take on wings
ORIGINAL: Shoe
HOW does that EXPLAIN the Incredible DOWNWASH from a helicopter when it is hovering - have you tried standing under a hovering helicopter? - Good luck!
Quite easily actually... The air in the helicopter's downwash has to come from somewhere. For a helicopter in a hover, it's quite apparent that the air in the downwash comes from above the rotor disk. What causes initially stationary air to accelerate downward toward the rotor disk? Low pressure above the rotor. Is it the low pressure above the rotor disk or the downwash that's responsible for the lift force on the helicopter? The answer to that question is simply: ''yes''. You can't have the pressure differential across the rotor disk without the downwash... and you can't have the downwash without the pressure differential.
HOW does that EXPLAIN the Incredible DOWNWASH from a helicopter when it is hovering - have you tried standing under a hovering helicopter? - Good luck!
Well stated, Shoe. I understood you perfectly. But then I understood the concept already. It's difficult for some folks to get their minds wrapped around the idea that all these constructs are but snapshots of a process.
Lets try an analogy. What is sound ? Is it the vibrating of the speaker's vocal chords ? Is it the pressure waves in the air created by the speaker ? Is it the sympathetic vibration of the listener's ear drums ? Or is it the motion of the fluid in the listener's inner ear ? The answer to all of the above is YES ! Every observation on the sound phenomenon is valid and none excludes or dispels the other. Just steps in the process.
So it is with lift.
Dick
12-22-2010, 05:21 AM
#47
RE: my take on wings
ORIGINAL: Rob2160
HOW does that EXPLAIN the Incredible DOWNWASH from a helicopter when it is hovering - have you tried standing under a hovering helicopter? - Good luck!
HOW does that EXPLAIN the Incredible DOWNWASH from a helicopter when it is hovering - have you tried standing under a hovering helicopter? - Good luck!
http://www.modelflying.co.uk/sites/3...7/att00044.jpg
12-22-2010, 07:41 AM
#48
RE: my take on wings
ORIGINAL: Lnewqban
This picture demonstrates that there is an incredible UPWASH as well:
http://www.modelflying.co.uk/sites/3...7/att00044.jpg
This picture demonstrates that there is an incredible UPWASH as well:
http://www.modelflying.co.uk/sites/3...7/att00044.jpg
If my aerodynamics instructors had used examples like that I would have paid more attention in class !
Dick
12-29-2010, 06:18 AM
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RE: my take on wings
My take on all of this - and it doesn't take a rocket scientist ...
Stand behind a prop when it's spinning. Or stand under a helicopter when it's taking off. You'll feel the force in the moving air, the force that ultimately moves that object, when you do that. Action/Reaction.
An airplane wing uses the same technology to move air that props and rotors use. But because an airplane wing doesn't keep rotating over the same spot, it's hard to feel the air that a wing moves downward when it's lifting.
But that air is being forced downward by the wing nevertheless, when a plane is flying.
Action and reaction.
Anything that forces air in one direction will push itself in the other direction. And it's patently obvious that airplane wings force lots and lots air in the direction opposite to the lift being created.
Here's where Bernoulli comes into play
[ul][*] A flat plate is at 0 angle of attack. Equal pressure on top and bottom of plate.[*] The plate's leading edge is raised a couple degrees.[*] An area of lower air pressure above the plate is created by this action. (Common sense dictates this)[*] This causes the air to move faster above the plate.[*] The air also has a quality that causes it to stick to the top of the plate.[*] So, the air moving over the top of the plate is increased in velocity by the vacuum.[*] And the air moving over the top of the plate is deflected downward by the angle of the plate.
[/ul]
Two important things happened when we tipped up the plate ...
1) The air was deflected downward.
2) The velocity of the air deflected downward was increased.
The result of the above is a lift vector.
Enjoy ...
Stand behind a prop when it's spinning. Or stand under a helicopter when it's taking off. You'll feel the force in the moving air, the force that ultimately moves that object, when you do that. Action/Reaction.
An airplane wing uses the same technology to move air that props and rotors use. But because an airplane wing doesn't keep rotating over the same spot, it's hard to feel the air that a wing moves downward when it's lifting.
But that air is being forced downward by the wing nevertheless, when a plane is flying.
Action and reaction.
Anything that forces air in one direction will push itself in the other direction. And it's patently obvious that airplane wings force lots and lots air in the direction opposite to the lift being created.
Here's where Bernoulli comes into play
[ul][*] A flat plate is at 0 angle of attack. Equal pressure on top and bottom of plate.[*] The plate's leading edge is raised a couple degrees.[*] An area of lower air pressure above the plate is created by this action. (Common sense dictates this)[*] This causes the air to move faster above the plate.[*] The air also has a quality that causes it to stick to the top of the plate.[*] So, the air moving over the top of the plate is increased in velocity by the vacuum.[*] And the air moving over the top of the plate is deflected downward by the angle of the plate.
[/ul]
Two important things happened when we tipped up the plate ...
1) The air was deflected downward.
2) The velocity of the air deflected downward was increased.
The result of the above is a lift vector.
Enjoy ...