Daanopperman,...To respond to your query,lets take the simplest model you cited like the sheet of paper which should serve to answer the other questions you raised. Excuse me if I do not use any academic jargon or abbreviations, because the easiest way to lose someone is to use terms that are not every day language.
Bear in mind that on each side of that paper there is about 1kg/sq/cm of air pressure. Air is also like electricity, it travels in a stream or circuit.
Now if you blow over the paper it flows over the surface, but will not leave that surface because of the air pressure.
Once you initiate a stream of air, it continues to flow due to its mass, but it will not leave a vacuum behind it, so air comes in to fill the gap including the surface of the paper.
As with any object that is in a stream of air, it represents an obstruction so air must flow closely around it, due to the atmospheric pressure. If the flow is intense, a low pressure will result behind the object.
I must reiterate that the air in a flow under the most vacuum constraint near the surface will travel fastest, due to its reduced mass.
The Physics of Wing Lift...Logic versus tradition.
Moderator: scott
re: The Physics of Wing Lift...Logic versus tradition.
It would have been nice to be able to see the plane you fly 'oldNick'.
Is it still fuel powered or have you gone over to electrics.
Model planes have come a long way since the 50's.
I was invited to a club meet by a friend of my daughter's.
He had a plane that ran on straight fuel. When he took his plane up I was so impressed. I've never seen such incredible aerobatics in my life. I suggested that he enter international competitions. Oh no, he said, "Been there and done that".
He now only flies for enjoyment.
Is it still fuel powered or have you gone over to electrics.
Model planes have come a long way since the 50's.
I was invited to a club meet by a friend of my daughter's.
He had a plane that ran on straight fuel. When he took his plane up I was so impressed. I've never seen such incredible aerobatics in my life. I suggested that he enter international competitions. Oh no, he said, "Been there and done that".
He now only flies for enjoyment.
re: The Physics of Wing Lift...Logic versus tradition.
Hi Trevor,
I am all electric now and I don't have any fixed wing aircraft at the moment, but the next one will be of my own design. However I do have 3 quadcopters
the biggest I use for aerial photography, It has GPS and will hover where I put it. I also have 3 helicopters, 2 small ones for indoor use. Plus 2 ornithopters , these are propelled with flapping wings, although these 2 are only kids toys they fly well and are easy to control and glide nicely for landing.
all the above were purchased for experimental purposes only. lol.
I agree with your flat wing theory, it's all about angle of attack.
photos to follow when I figure out how to post them.
I am all electric now and I don't have any fixed wing aircraft at the moment, but the next one will be of my own design. However I do have 3 quadcopters
the biggest I use for aerial photography, It has GPS and will hover where I put it. I also have 3 helicopters, 2 small ones for indoor use. Plus 2 ornithopters , these are propelled with flapping wings, although these 2 are only kids toys they fly well and are easy to control and glide nicely for landing.
all the above were purchased for experimental purposes only. lol.
I agree with your flat wing theory, it's all about angle of attack.
photos to follow when I figure out how to post them.
re: The Physics of Wing Lift...Logic versus tradition.
Wow!...that is so great. I also like to be original.
When I was at the aero-plane club meet, a guy had small quad-copter and he was surveying the surrounding bush using virtual glasses.I thought that was so cool.
You won't believe it but 25 years ago my dream was to build a man piloted hexa-copter with individual motors on each of the six props, simply because I thought that was the safest way to fly. Now its all coming to pass.
Also , when I was 12 years old I built several ornithopters out of balsa, powered by rubber bands. I am 72 now,...my how time flies.
When I was at the aero-plane club meet, a guy had small quad-copter and he was surveying the surrounding bush using virtual glasses.I thought that was so cool.
You won't believe it but 25 years ago my dream was to build a man piloted hexa-copter with individual motors on each of the six props, simply because I thought that was the safest way to fly. Now its all coming to pass.
Also , when I was 12 years old I built several ornithopters out of balsa, powered by rubber bands. I am 72 now,...my how time flies.
re: The Physics of Wing Lift...Logic versus tradition.
Your mention of http://www.youtube.com/watch?v=a-qS7oN-3tA
brought back some memories, I gave up early and my interests went to
gyrocopters http://en.wikipedia.org/wiki/Autogyro.
Built many balsa wood, tissue papered models, many from store bought kits and some of my own design. All were powered by fox or McCoy glow plug engines, "U" wired control.
Upon entering High-school I signed up for a machine shop course, it was mandatory that the first semester was "Mechanical drafting" upon completion I was then allowed into the machine shop.
I built a few wrought iron coffee tables for family members, and then proceeded to start fabrication of a small jet turbine engine using White gas as not only a lubricant for shaft bearings, but vaporized for combustion. It took me until the end of my sophomore year to complete this project. A shop air compressor and blow gun was used to start the engine which was tied down to a wooden base and clamped in a bench vise. It ran well and was extremely loud. The instructor who never thought it would run, made me shut it down in fear of blowing out shop windows.
During the last week of the school year a fellow classmate, got to messing with it behind my back. He dropped it on the concrete work floor, that was the end of my jet engine project.
Ralph
brought back some memories, I gave up early and my interests went to
gyrocopters http://en.wikipedia.org/wiki/Autogyro.
Built many balsa wood, tissue papered models, many from store bought kits and some of my own design. All were powered by fox or McCoy glow plug engines, "U" wired control.
Upon entering High-school I signed up for a machine shop course, it was mandatory that the first semester was "Mechanical drafting" upon completion I was then allowed into the machine shop.
I built a few wrought iron coffee tables for family members, and then proceeded to start fabrication of a small jet turbine engine using White gas as not only a lubricant for shaft bearings, but vaporized for combustion. It took me until the end of my sophomore year to complete this project. A shop air compressor and blow gun was used to start the engine which was tied down to a wooden base and clamped in a bench vise. It ran well and was extremely loud. The instructor who never thought it would run, made me shut it down in fear of blowing out shop windows.
During the last week of the school year a fellow classmate, got to messing with it behind my back. He dropped it on the concrete work floor, that was the end of my jet engine project.
Ralph
re: The Physics of Wing Lift...Logic versus tradition.
Great Ralph, it looks like us old guys have a lot in common.I've also been fascinated with jets.
It looks like the electrics are taking over though.
One day I foresee the airliners going over to electrics because these new nano technology batteries are light and the amp/hour capacity is 10 times conventional ones...who knows!
It looks like the electrics are taking over though.
One day I foresee the airliners going over to electrics because these new nano technology batteries are light and the amp/hour capacity is 10 times conventional ones...who knows!
re: The Physics of Wing Lift...Logic versus tradition.
I subscribe to the following technology site which posts updates on just about everything, including battery technology, aviation, automotive etc...
You may find this last post of interest, and suggest you subscribe.
http://www.gizmag.com/lockeheed-martin- ... 6-90303542
Go here to subscribe to Gizmag http://feeds.feedblitz.com/Gizmag
Warning! some of gizmag's posts require extensive scrolling as they cover a number of topics.
You may find this last post of interest, and suggest you subscribe.
http://www.gizmag.com/lockeheed-martin- ... 6-90303542
Go here to subscribe to Gizmag http://feeds.feedblitz.com/Gizmag
Warning! some of gizmag's posts require extensive scrolling as they cover a number of topics.
re: The Physics of Wing Lift...Logic versus tradition.
Thanks a lot Ralph, that Giizmag website looks really good.
I like it because it is so comprehensive, covering all fields of science.
I like it because it is so comprehensive, covering all fields of science.
re: The Physics of Wing Lift...Logic versus tradition.
Your welcome,
Added note; When watching a video such as the one regarding the SR72, do not get impatient and close it, there are often more than one feature presented. I believe there are at least five on the SR72 video.
Ralph
Added note; When watching a video such as the one regarding the SR72, do not get impatient and close it, there are often more than one feature presented. I believe there are at least five on the SR72 video.
Ralph
re: The Physics of Wing Lift...Logic versus tradition.
http://www.youtube.com/watch?v=edZLT9eymIk
This quasi-steady state animation shows a Van de Vooren 15% thickness ratio symmetric aerofoil cycling sinusoidally through a +-15 deg angle of attack range. The first animation shows the streamlines and pressure field, the second shows the normal forces on the aerofoil, the third the lift component, and the fourth the pressure drag c...omponent (which integrates to zero in a potential flow). The purpose of this animation was to reveal how the majority of the lift force comes from the upper surface near the leading edge. Thus rather than being held in the sky by sitting on a cushion of high pressure, it is more the case that you are being suspended by imaginary strings connected to the top of the wing!
In reality, pitching the aerofoil as was done in this animation would result in vortex shedding at the trailing edge due to the change in circulation with angle of attack. This occurs to satisfy the Kelvin condition of constant total circulation enclosing body and wake for all time. Such a code is in development and an unsteady flow animation of a pitching aerofoil with wake roll-up is coming soon.
This quasi-steady state animation shows a Van de Vooren 15% thickness ratio symmetric aerofoil cycling sinusoidally through a +-15 deg angle of attack range. The first animation shows the streamlines and pressure field, the second shows the normal forces on the aerofoil, the third the lift component, and the fourth the pressure drag c...omponent (which integrates to zero in a potential flow). The purpose of this animation was to reveal how the majority of the lift force comes from the upper surface near the leading edge. Thus rather than being held in the sky by sitting on a cushion of high pressure, it is more the case that you are being suspended by imaginary strings connected to the top of the wing!
In reality, pitching the aerofoil as was done in this animation would result in vortex shedding at the trailing edge due to the change in circulation with angle of attack. This occurs to satisfy the Kelvin condition of constant total circulation enclosing body and wake for all time. Such a code is in development and an unsteady flow animation of a pitching aerofoil with wake roll-up is coming soon.
re: The Physics of Wing Lift...Logic versus tradition.
http://www.youtube.com/watch?v=q_eMQvDoDWk
Published on Jul 29, 2013
more at http://scitech.quickfound.net
"1930s test conducted at NASA Langley Research Center's 6 by 19 inch Transonic Tunnel during its NACA era."
Public domain film from NASA, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied.
The film was silent. I have added music created by myself using the Reaper Digital Audio Workstation and the Proteus VX VST instrument plugin.
http://creativecommons.org/licenses/b...
http://en.wikipedia.org/wiki/Camber_(...)
In aeronautics and aeronautical engineering, camber is the asymmetry between the top and the bottom surfaces of an aerofoil. An aerofoil that is not cambered is called a symmetric aerofoil. The benefits of camber, in contrast to symmetric aerofoils, were discovered and first utilized by Sir George Cayley in the early 19th century...
Overview
Camber is usually designed into an aerofoil to increase the maximum lift coefficient. This minimises the stalling speed of aircraft using the aerofoil. Aircraft with wings based on cambered aerofoils usually have lower stalling speeds than similar aircraft with wings based on symmetric aerofoils.
An aircraft designer may also reduce the camber of the outboard section of the wings to increase the critical angle of attack (stall angle) at the wing tips. When the wing approaches the stall angle this will ensure that the wing root stalls before the tip, giving the aircraft resistance to spinning and maintaining aileron effectiveness close to the stall.
Some recent designs use negative camber. One such design is called the supercritical aerofoil. It is used for near-supersonic flight, and produces a higher lift to drag ratio at near supersonic flight than traditional aerofoils. Supercritical aerofoils employ a flattened upper surface, highly cambered (curved) aft section, and greater leading edge radius as compared to traditional aerofoil shapes. These changes delay the onset of wave drag...
http://en.wikipedia.org/wiki/Flap_(ai...)
Flaps are hinged surfaces mounted on the trailing edges of the wings of a fixed-wing aircraft to reduce the speed at which an aircraft can be safely flown and to increase the angle of descent for landing. They shorten takeoff and landing distances. Flaps do this by lowering the stall speed and increasing the drag.
Extending flaps increases the camber or curvature of the wing, raising the maximum lift coefficient—or the lift a wing can generate. This allows the aircraft to generate as much lift but at a lower speed, reducing the stalling speed of the aircraft, or the minimum speed at which the aircraft will maintain flight. Extending flaps increases drag which can be beneficial during approach and landing because it slows the aircraft. On some aircraft, a useful side effect of flap deployment is a decrease in aircraft pitch angle which improves the pilot's view of the runway over the nose of the aircraft during landing. However the flaps may also cause pitch-up, depending on the type of flap and the location of the wing.
There are many different types of flaps used...
The Fowler, Fairey-Youngman and Gouge types of flap increase the planform area of the wing in addition to changing the camber. The larger lifting surface reduces wing loading and allows the aircraft to generate the required lift at a lower speed and reduces stalling speed...
http://en.wikipedia.org/wiki/Leading_...
A leading edge slot is a fixed aerodynamic feature of the wing of some aircraft to reduce the stall speed and promote good low-speed handling qualities. A leading edge slot is a span-wise gap in each wing, allowing air to flow from below the wing to its upper surface. In this manner they allow flight at higher angles of attack and thus reduce the stall speed...
Purpose and development
At an angle of attack above about 15° many airfoils enter the stall. Modification of such an airfoil with a fixed leading edge slot can increase the stalling angle to between 22° and 25°.
Slots were first developed by Handley Page in 1919 and the first aircraft to fly with them was the experimental H.P.17, a modified Airco DH.9A. The first aircraft fitted with controllable slots was the Handley Page H.P.20. Licensing the design became one of Handley Page's major sources of income in the 1920s.
Similar, but retractable, leading edge devices are called slats. When the slat opens, it creates a slot between the slat and the remainder of the wing; retracted, the drag is reduced.
A fixed leading edge slot can increase the maximum lift coefficient of an airfoil section by 40%. In conjunction with a slat, the increase in maximum lift coefficient can be 50% or even 60%...
Unlike trailing edge flaps, leading edge slots do not increase the lift coefficient at zero angle of attack since they do not alter the camber.
Published on Jul 29, 2013
more at http://scitech.quickfound.net
"1930s test conducted at NASA Langley Research Center's 6 by 19 inch Transonic Tunnel during its NACA era."
Public domain film from NASA, slightly cropped to remove uneven edges, with the aspect ratio corrected, and mild video noise reduction applied.
The film was silent. I have added music created by myself using the Reaper Digital Audio Workstation and the Proteus VX VST instrument plugin.
http://creativecommons.org/licenses/b...
http://en.wikipedia.org/wiki/Camber_(...)
In aeronautics and aeronautical engineering, camber is the asymmetry between the top and the bottom surfaces of an aerofoil. An aerofoil that is not cambered is called a symmetric aerofoil. The benefits of camber, in contrast to symmetric aerofoils, were discovered and first utilized by Sir George Cayley in the early 19th century...
Overview
Camber is usually designed into an aerofoil to increase the maximum lift coefficient. This minimises the stalling speed of aircraft using the aerofoil. Aircraft with wings based on cambered aerofoils usually have lower stalling speeds than similar aircraft with wings based on symmetric aerofoils.
An aircraft designer may also reduce the camber of the outboard section of the wings to increase the critical angle of attack (stall angle) at the wing tips. When the wing approaches the stall angle this will ensure that the wing root stalls before the tip, giving the aircraft resistance to spinning and maintaining aileron effectiveness close to the stall.
Some recent designs use negative camber. One such design is called the supercritical aerofoil. It is used for near-supersonic flight, and produces a higher lift to drag ratio at near supersonic flight than traditional aerofoils. Supercritical aerofoils employ a flattened upper surface, highly cambered (curved) aft section, and greater leading edge radius as compared to traditional aerofoil shapes. These changes delay the onset of wave drag...
http://en.wikipedia.org/wiki/Flap_(ai...)
Flaps are hinged surfaces mounted on the trailing edges of the wings of a fixed-wing aircraft to reduce the speed at which an aircraft can be safely flown and to increase the angle of descent for landing. They shorten takeoff and landing distances. Flaps do this by lowering the stall speed and increasing the drag.
Extending flaps increases the camber or curvature of the wing, raising the maximum lift coefficient—or the lift a wing can generate. This allows the aircraft to generate as much lift but at a lower speed, reducing the stalling speed of the aircraft, or the minimum speed at which the aircraft will maintain flight. Extending flaps increases drag which can be beneficial during approach and landing because it slows the aircraft. On some aircraft, a useful side effect of flap deployment is a decrease in aircraft pitch angle which improves the pilot's view of the runway over the nose of the aircraft during landing. However the flaps may also cause pitch-up, depending on the type of flap and the location of the wing.
There are many different types of flaps used...
The Fowler, Fairey-Youngman and Gouge types of flap increase the planform area of the wing in addition to changing the camber. The larger lifting surface reduces wing loading and allows the aircraft to generate the required lift at a lower speed and reduces stalling speed...
http://en.wikipedia.org/wiki/Leading_...
A leading edge slot is a fixed aerodynamic feature of the wing of some aircraft to reduce the stall speed and promote good low-speed handling qualities. A leading edge slot is a span-wise gap in each wing, allowing air to flow from below the wing to its upper surface. In this manner they allow flight at higher angles of attack and thus reduce the stall speed...
Purpose and development
At an angle of attack above about 15° many airfoils enter the stall. Modification of such an airfoil with a fixed leading edge slot can increase the stalling angle to between 22° and 25°.
Slots were first developed by Handley Page in 1919 and the first aircraft to fly with them was the experimental H.P.17, a modified Airco DH.9A. The first aircraft fitted with controllable slots was the Handley Page H.P.20. Licensing the design became one of Handley Page's major sources of income in the 1920s.
Similar, but retractable, leading edge devices are called slats. When the slat opens, it creates a slot between the slat and the remainder of the wing; retracted, the drag is reduced.
A fixed leading edge slot can increase the maximum lift coefficient of an airfoil section by 40%. In conjunction with a slat, the increase in maximum lift coefficient can be 50% or even 60%...
Unlike trailing edge flaps, leading edge slots do not increase the lift coefficient at zero angle of attack since they do not alter the camber.
re: The Physics of Wing Lift...Logic versus tradition.
Thanks Ralph for all the info which I find very interesting and useful.
The purpose of this thread is to help even the layman visualize how and why planes fly. I will try to do this in my next post.
I mentioned that the essential ingredient is the angle of attack, but that is not the whole story. Of course camber is important, especially for slow speed planes to optimize the deft handling of the air stream.
At the risk of sounding arrogant, I have learned not to just accept what is dished up to one, but to work it out in your own mind using all your accumulated hands on experience.
The result can turn out very different to what we are taught.
The purpose of this thread is to help even the layman visualize how and why planes fly. I will try to do this in my next post.
I mentioned that the essential ingredient is the angle of attack, but that is not the whole story. Of course camber is important, especially for slow speed planes to optimize the deft handling of the air stream.
At the risk of sounding arrogant, I have learned not to just accept what is dished up to one, but to work it out in your own mind using all your accumulated hands on experience.
The result can turn out very different to what we are taught.
-
eccentrically1
- Addict
- Posts: 3166
- Joined: Sat Jun 11, 2011 10:25 pm
this is useful
http://science.howstuffworks.com/transp ... lider3.htm
flying is using the air as a working mass. wings are most efficient shape nature has shown to convert its fluid properties' effect on the solid surface into a usually controlled dynamic motion. but it's not perpetual motion, or overunity. the coefficients don't imply that. they're a function of AoA, Mach number and Reynolds number.
http://en.wikipedia.org/wiki/Lift_coefficient
http://en.wikipedia.org/wiki/Mach_number
http://en.wikipedia.org/wiki/Reynold_number
http://en.wikipedia.org/wiki/Drag_coefficient
http://science.howstuffworks.com/transp ... lider3.htm
flying is using the air as a working mass. wings are most efficient shape nature has shown to convert its fluid properties' effect on the solid surface into a usually controlled dynamic motion. but it's not perpetual motion, or overunity. the coefficients don't imply that. they're a function of AoA, Mach number and Reynolds number.
http://en.wikipedia.org/wiki/Lift_coefficient
http://en.wikipedia.org/wiki/Mach_number
http://en.wikipedia.org/wiki/Reynold_number
http://en.wikipedia.org/wiki/Drag_coefficient
re: The Physics of Wing Lift...Logic versus tradition.
Eccentrically1,...I'm not questioning the formula,as I said before you can get any equation to work using coefficients and constants.
My argument is how they perceive a plane stays in the air. It's not just about angle of attack or circulation for that matter.
There is a deeper principle involved.
My argument is how they perceive a plane stays in the air. It's not just about angle of attack or circulation for that matter.
There is a deeper principle involved.
-
eccentrically1
- Addict
- Posts: 3166
- Joined: Sat Jun 11, 2011 10:25 pm
Re: re: The Physics of Wing Lift...Logic versus tradition.
read the article. it does drop like a stone. that's what it does to thrust itself up to gliding speed. remember the feather and the hammer on the moon. it's just more aerodynamic than a stone.trevor wrote:What I am mainly concerned with is; What is the main reason why even a flat wing glider can fly so beautifully without dropping like a stone.
this was discussed on the other threads already.Trevor wrote:Okay here goes controversy number one.
Most guys who know planes know that the vacuum effect over the wing is caused by the angle of attack on the air mass,and because of its inertial mass it is slow to fill that space the front shoulder of the wing has left,creating reduced pressure.
Now we get another school that insist that the vacuum is created by the venturi effect.
They say that high speed air lowers it's atmospheric pressure on top of the wing and that is what allows a plane to fly.Unfortunately they cannot say why this happens but it just does.
My contention is that they have actually got the proverbial,'Cart before the horse'.
Here's what actually happens.
The angle of attack into the air creates reduced pressure over the wing and the highest vacuum is closest to the surface,being air that has far less mass and under the greatest constraint to flow in the direction of travel.As a result this thin skin of air will expand much faster exponentially in the direction of travel than,the denser layer,...the whole reason for its higher speed.
So in short it is actually the vacuum that creates the high speed air and not the high speed air that creates the vacuum.