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เนื้อหาบางส่วนที่เกี่ยวข้องกับหัวข้อairfoil คือ

เมื่อมองดูแอร์ฟอยล์ทั่วไป เช่น ปีก จากด้านข้าง ลักษณะการออกแบบหลายอย่างจะชัดเจนขึ้น คุณจะเห็นได้ว่ามีความโค้ง (หรือมุมแคมเบอร์) ของพื้นผิวด้านบนและด้านล่างของปีกแตกต่างกัน มุมแคมเบอร์ของพื้นผิวด้านบนนั้นเด่นชัดกว่าพื้นผิวด้านล่างซึ่งมักจะค่อนข้างแบน เส้นคอร์ดเป็นเส้นอ้างอิงที่ลากจากจุดศูนย์กลางของขอบนำตรงผ่านปีกไปยังขอบท้าย ระยะห่างจากเส้นคอร์ดนี้ไปยังพื้นผิวด้านบนและด้านล่างของปีกแสดงปริมาณแคมเบอร์บนและล่าง ณ จุดใดก็ได้ เส้นอ้างอิงอีกเส้นหนึ่งซึ่งลากจากขอบด้านบนไปยังขอบด้านหลังคือเส้นแคมเบอร์เฉลี่ย เส้นค่าเฉลี่ยนี้เท่ากันทุกจุดจากพื้นผิวด้านบนและด้านล่าง airfoils ที่แตกต่างกันมีลักษณะการบินที่แตกต่างกัน น้ำหนัก ความเร็ว และจุดประสงค์ของเครื่องบินแต่ละลำจะกำหนดรูปร่างของแอร์ฟอยล์ ฟอยล์ที่มีประสิทธิภาพมากที่สุดสำหรับการผลิตลิฟต์ที่ใหญ่ที่สุดคือหนึ่งที่มีพื้นผิวด้านล่างเว้าหรือ “ตักออก” ในทางกลับกัน airfoil ที่เพรียวบางอย่างสมบูรณ์แบบและมีความต้านทานลมน้อยในบางครั้งไม่มีกำลังยกมากพอที่จะขึ้นเครื่องบิน ออกจากพื้นดิน ถ้าปีกเป็นรูปหยดน้ำ ความเร็วและความดันของอากาศที่ไหลผ่านด้านบนและด้านล่างจะเท่ากันทั้งสองข้าง แต่ถ้าปีกรูปหยดน้ำถูกตัดครึ่งทางยาว รูปแบบที่คล้ายกับส่วนของปีกที่คุ้นเคยจะส่งผลให้ ความแตกต่างของแรงดันระหว่างพื้นผิวด้านบนและด้านล่างของปีกเพียงอย่างเดียว จะไม่นับรวมแรงยกทั้งหมดที่เกิดขึ้น การไหลของอากาศจากด้านบนและด้านล่างของปีกทำให้เกิดการชะล้างลง การล้างลงนี้ไหลไปตามกระแสจากด้านล่างของปีกที่ขอบด้านท้าย เมื่อใช้กฎข้อที่สามของนิวตัน ปฏิกิริยาของการไหลย้อนกลับนี้ส่งผลให้เกิดแรงไปข้างหน้าบนปีก แรงยกยังเกิดจากสภาวะแรงดันใต้แผ่นลม เนื่องจากลักษณะที่อากาศไหลผ่านใต้แผ่นลม ทำให้เกิดแรงดันบวกหรือแรงดันสูง มุมของการโจมตีของปีกคือมุมระหว่างเส้นคอร์ดกับการไหลของอากาศกับขอบด้านบนของปีก ค่าเฉลี่ยของความแปรผันของความดันสำหรับมุมของการโจมตีใด ๆ เรียกว่าจุดศูนย์กลางของแรงกด ระบุเป็น CP . . แรงแอโรไดนามิกทั้งหมดกระทำผ่านจุดศูนย์กลางแรงดัน ที่มุมโจมตีสูง จุดศูนย์กลางแรงดันเคลื่อนไปข้างหน้า ในขณะที่มุมโจมตีต่ำ จุดศูนย์กลางแรงดันจะเคลื่อนที่ไปทางท้ายเรือ การเดินทางของศูนย์ความดันมีความสำคัญมาก เนื่องจากความสมดุลของอากาศพลศาสตร์และความสามารถในการควบคุมของเครื่องบินถูกควบคุมโดยการเปลี่ยนแปลงของศูนย์กลางความกดอากาศ การผลิตลิฟต์นั้นซับซ้อนกว่าแรงดันที่แตกต่างกันอย่างง่ายระหว่างพื้นผิวปีกบนและปีกล่าง อันที่จริง airfoils จำนวนมากไม่มีพื้นผิวด้านบนที่ยาวกว่าด้านล่าง สิ่งเหล่านี้เรียกว่า airfoils สมมาตร ฟอยล์แบบสมมาตรมีให้เห็นในเครื่องบินความเร็วสูงที่มีปีกแบบสมมาตร หรือบนใบพัดแบบสมมาตรสำหรับเฮลิคอปเตอร์หลายรุ่นที่มีพื้นผิวด้านบนและด้านล่างเหมือนกัน ด้วยฟอยล์แบบสมมาตร ความสัมพันธ์ของฟอยล์อากาศกับกระแสลมที่พุ่งเข้ามา หรือมุมของการโจมตีนั้นแตกต่างกัน เมื่อปีกเคลื่อนผ่านอากาศ ปีกจะเอียงขึ้นไปต้านกระแสลม ทำให้เกิดกระแสที่แตกต่างกันซึ่งเกิดจากความสัมพันธ์ของปีกกับอากาศที่จะมาถึง ลองนึกถึงมือที่วางอยู่นอกหน้าต่างรถด้วยความเร็วสูง หากมือเอียงไปในทิศทางใดทิศทางหนึ่ง มือจะเลื่อนขึ้นหรือลง ซึ่งเกิดจากการโก่งตัวซึ่งทำให้อากาศหมุนรอบวัตถุภายในกระแสลม จากการเปลี่ยนแปลงนี้ ความเร็วของวัตถุจะเปลี่ยนทั้งขนาดและทิศทาง ส่งผลให้มีแรงและทิศทางความเร็วที่วัดได้ จนถึงตอนนี้ เราเน้นเฉพาะการไหลของอากาศผ่านพื้นผิวด้านบนและด้านล่างของแผ่นลมเท่านั้น แม้ว่าลิฟต์ส่วนใหญ่จะสร้างขึ้นจากสองมิตินี้ ซึ่งเป็นมิติที่สาม แต่ส่วนปลายของปีกก็มีเอฟเฟกต์แอโรไดนามิกเช่นกัน บริเวณความกดอากาศสูงที่อยู่ด้านล่างของ airfoil จะดันไปรอบๆ ส่วนปลายไปยังบริเวณความกดอากาศต่ำที่อยู่ด้านบน การกระทำนี้จะสร้างกระแสหมุนที่เรียกว่ากระแสน้ำวนปลายปีก กระแสน้ำวนไหลไปทางด้านหลัง airfoil ทำให้เกิด downwash ซึ่งขยายกลับไปยังขอบด้านท้ายของ airfoil การล้างลงนี้ส่งผลให้การยกโดยรวมลดลงสำหรับส่วนที่ได้รับผลกระทบของปีก ผู้ผลิตเครื่องบินได้พัฒนาวิธีการต่างๆ เพื่อต่อต้านการกระทำนี้ สามารถเพิ่ม Winglets ที่ปลาย airfoil เพื่อลดการไหลนี้ ปีกนกทำหน้าที่เป็นเขื่อนป้องกันไม่ให้กระแสน้ำวนก่อตัว Winglets สามารถอยู่ด้านบนหรือด้านล่างของ airfoil อีกวิธีหนึ่งในการตอบโต้การไหลคือการทำให้ปลาย airfoil เรียว ลดความแตกต่างของแรงดันและทำให้กระแสลมรอบ ๆ ปลายเรียบ ดัดแปลงจากคู่มือความรู้ด้านการบินของนักบิน .

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ภาพถ่ายที่เกี่ยวข้องกับหัวข้อของairfoil คือ

Airfoil Design
Airfoil Design

นอกจากการอ่านข้อมูลเกี่ยวกับบทความนี้ Airfoil Design คุณสามารถค้นพบบทความเพิ่มเติมด้านล่าง

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ข้อมูลบางส่วนที่เกี่ยวข้องกับairfoil คือ

#Airfoil #Design.

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Airfoil Design.

airfoil คือ.

หวังว่าค่านิยมบางอย่างที่เรามอบให้จะเป็นประโยชน์กับคุณ ขอบคุณมากสำหรับการดูข้อมูลairfoil คือของเรา

48 thoughts on “Airfoil Design | ข้อมูลที่มีรายละเอียดมากที่สุดทั้งหมดเกี่ยวกับairfoil คือ

  1. Tech Stuf says:

    Reaction lift is indeed occurring. If a constant stream of solid particles, (say small plastic air soft pellets, for example) were aimed at the front of the wing, of sufficiently large volume to stream past the top and bottom of the wing, it's obvious that the wing would rise. And this is without the Coanda effect taking place.

    So, both reaction lift (most often the majority) resulting from impact with the bottom of the wing by the aggregate mass of the air, combined with the boundary layer mass of air flowing over the top and creating a thin, negative pressure area near the top surface of the wing to which it adheres; serve to maximize lift efficiency.

    What occurs on the top wing surface is analagous to the effects of orbiting bodies and the "sling shot" effect used by space probes, only substituting vacuum adhesion for gravity. This is also aptly demonstrated with the "chain fountain" phenomenon. A partial orbit of a mass causing lift in the direction of a vector originating at the arc's center of radius and extending out, bisecting the arc at it's center.

    This partial orbit of the air mass over the wing, tugging on the wing surface via suction, added to the upward push from the air mass deflecting off the bottom, share responsibilty for lifting the wing.

    Both air and sea creatures make very efficient use of alternating these effects above and below the wing or tail (and to appreciable degree with sea creatures, their bodies.) Rapidly alternating negative and positive pressures enable the Black Marlin for instance, to hit a reported 82mph.

    Good Journeys All

    P.S. See – "Huge media blackout regarding supermoons" on the net

  2. blaster 0416 says:

    I have another bone to pick. Air does not "suck". There is no such thing as "negative pressure". There is only less pressure than ambient, but it is still positive pressure. Your blue arrows suggest that the air is magically pulling on the upper surface and that is incorrect. Air pressure can ONLY push. There is no "pulling" of air. The illision is done by reducing the pressure on one side, Therfore allowing the opposing higher pressure to do all of the pushing. That includes the positive air pressure on the inside of the wing pushing on the inside of the upper wing skin.

  3. blaster 0416 says:

    I have an issue with your illustration at 4:34. Looking at the small blue arrows, you purpetuate the myth that the air being split at the leading edge matches up again at the trailing edge. This is false. The air on the top of the wing goes faster and beats the air under the wing at the trailing edge.

  4. Peter Phil says:

    Most of your lecture is incorrect bro… it started when u said the airflow over the top has to be faster because the upper surface is longer… seems you think molecules above and below are somehow entangled like quantum mechanics and need to return into each other’s arms… the transit times above and below are different bro… this is a gaseous fluid and there is nothing in aerodynamics that indicates fluids have to be the same after playing host to a transiting wing… pretending they have to be the same is not physics but a belief system such as religion is based on belief without good evidence…
    if u don’t know bro just say so… BUT don’t churn BS to the uninitiated who will be none the wiser.

  5. K. Chris Caldwell says:

    Wrong! Wrong! Wrong! And wrong again. It's now well established that Bernoulli effects have little to due with creating lift–flight. Neither does the Coanda effect. Lift is Newtonian, and comes about from pressure gradients due to the vacuum along the top-rear of an airfoil, not conservation of energy in air flows or Bernoulli pressure gradients.

    Lift results from air accelerated by the vacuum on the top-rear surface of an airfoil. However, Bernoulli's formulas are a close approximation for designing wings and explaining lift, and so are often used for just that.

    The formation of lift by an airfoil comes from the pressure gradient at the extreme vacuum found at the top-back surface of a wing. This vacuum accelerates the air just above the back surface of the wing down towards the back of the wing. This accelerated air in turn pulls down and accelerates more air from above the airfoil. The opposite and equal result of this pulling down, "scooping," of air and accelerating it downward is an upward force, lift. Lift is Newtonian.

    Airfoil equipped aircraft are essentially horizontal rockets, but much more efficient because of their ability to utilize graviational energy to create lift.

    The Coanda Effect is not the driver of lift either. It is caused by a weak electrical interaction between flowing fluid/air and the surface it is flowing over.

    As lift is Newtonian, it follows that the vast majority of the energy that is used to create and sustain lift, and maintain a heavier than air aircraft in the sky, comes from gravity, not from the aircraft's engines. That is why aircraft have non-powered glide-ratios and helicopters auto-rotation. Autogyros are an extreme example of this fact. If the energy from an aircraft's engines were the sole source of energy generating lift, a plane, like a rocket, would not be able to sustain flight for more than a few minutes; Also why jet packs will remain elusive for the foreseeable future.

    In the following video one can see the condensation in the vacuum induced low pressure area above the aircraft's wings. A closer look will reveal that this air is being pulled down, accelerated, and then pushed down at the back of the plane's wings:

    https://www.youtube.com/watch?v=t2SZawBVSrQ

    Hate away, but them's the facts.

  6. John Pombrio says:

    Cambridge University has debunked Bernoulli's principle as the means by which an airfoil creates lift. A wing need only have a curved surface to create lift. Period. "If a streamline is
    curved, there must be a pressure gradient across the streamline, with the pressure increasing in the direction away from the center of curvature. ' '
    A good example of this is a tornado that has curving air moving in a vortex. The center of the tornado has less pressure than the outside thus creating its "sucking" effect. No one has ever used Bernoulli's principle to explain a tornado!
    https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwi97cSJp9DsAhXMm-AKHTQ3CKwQFjAaegQIKhAC&url=http%3A%2F%2Fwww3.eng.cam.ac.uk%2Foutreach%2FProject-resources%2FWind-turbine%2Fhowwingswork.pdf&usg=AOvVaw12sAqN9m4QZOvdGdrW5wHE

  7. Observ45er says:

    This video only repeats very common misconceptions and invents a new one, as follows.

    .

    3:13 The low pressure above the wing allows higher pressure ahead of the wing to accelerate it to the higher speed. It is Newton. The force of pressure accelerates the mass of air.

    The movement of the wing creates pressure gradients and as Euler reported to us in the mid 1700s, Pressure gradients accelerate fluids.

    Bernoulli never said speed causes a pressure reduction. He only noted that the (static) pressure and velocity have an inverse relationship with no indication of cause and effect. This is a major, common misunderstanding.

    Euler determined that pressure gradients accelerate fluids toward the lower pressure. That is the opposite of the common misconception.



    3:29 The pressure difference top to bottom accounts for ALL THE LIFT. This 'a little of this and a little of that" is bad science. The same pressures that have the net upward lift force on the wing are the very same pressures that cause all accelerations around the wing including ahead, above, below, behind and around the tips.

    The higher pressure under the wing pushes up on the wing AND down on the air below to contribute to the down-wash.

    The lower pressure above the wing allows atmospheric pressure to push air above the wing downward, to also contribute to the down-wash.

    ..

    NOTE: the whole upward force on the wing is equal to the force required to accelerate all the air in the down-wash. THAT is what satisfies Newton's Third Law. The upward 'push" (force) on the wing equals the downward 'push' (force) on the air accelerated downward.

    The downward moving air does not push up on the wing. That air was pushed down by the pressures around the wing.

    The down-wash also does not push the wing forward. You've invented a new a fallacy. The net force fore-aft is rearward and is called drag and is not caused by the down-wash as explained above.

    When viewed from the still air frame of reference, the down-wash is moving slightly forward.

    ….

    4:27 Bernoulli's Principle is again misused. The flow is not slowed under the wing which is NOT the cause of the higher pressure. . That view is valid only in the stationary wing, wind tunnel reference frame only.

    In fact, REAL data from a REAL wing generating REAL lift flying through otherwise still air shows the lower air being moved forward in the direction of flight. This acceleration from still air is CAUSED BY the higher pressure at the lower surface. The increase in pressure at the surface is because the wing is pushing the air out of its way. This push increases the pressure, not the Bernoulli Principle Fallacy.

    ….

    The pressure increase below the wing in combination with the decrease above the wing provides the ENTIRE lift force.



    If by this magic, the down-wash did just happen to add to the lift, that "addition" would be exhibited as an increased pressure difference on the win…but it DOES NOT.

    Bernoulli's Principle causes nothing in the generation of lift because the "speed-causes-pressures" is a fallacy.

    It is all explained by Newton, BUT NOT with this ":reaction force" fallacy.

    Newton's Third Law "reaction force" is not an originating force, but is a direct result of the originating force which, in this case, is from the pressures around the wing as described above.

    ….

    At 7:11 Please listen to your words: “The high pressure area on the bottom of an airfoil pushes around the tip to the low pressure area on the top.”. This shows that you understand that pressure causes movement, but you fail to apply it on all the other parts of this and, therefore shows the problems with this explanation. The correct story uses this Pressure accelerated air in ALL aspects around the wing, because that I the real science.

    The tip vortex does not ‘create the down wash”. You already explained the down-wash without reference to the tip vortex. This is a flaw in this explanation. The tip vortex is CONSISTENT with the wing generated down-wash moving against the still air outside the wing span. Masses of air sliding along each other create vorticity (vortices) along the boundary of the two masses.



    At 7:47 Winglets DO NOT and CANNOT prevent the tip vortex from forming. They can only reduce the severity and the negative effect because they act to effectively lengthen the wingspan; longer wings have less severe vortices . See Doug McLean’s You Tube video on misconceptions for a full explanation.

    https://www.youtube.com/watch?v=QKCK4lJLQHU



    Though well-meaning, the 'Pilot's Handbook of Aeronautical Knowledge.' has bad information in it as do so many other publications and on-line resources such as YouTube.

  8. Sohail says:

    Hello Pilots,
    Do I understand it right that,
    Stall will happen when you have a large angle of attack at relative low speed?
    But if, with the Same Angle of Attack, the speed is much higher, then stall won't happen. Right? And the plane will climb up of course. Right?

    If not right, Then how come that fighter jets and other acrobatic planes can climb straight vertically?
    I suppose this is because of their high speed, which provides enough lift, no matter in what direction or angle they move.

    So why can't normal plans in a critical angle of attack give full thrust to gain more lift?
    The air is the same everywhere in the sky. Why behaves the air different if we want to fly in an angle which is not parallel to the horizon?

  9. Thailand Expat says:

    I am investigating airfoils to use for a sailboat Wingsail. Most wing sales use a symetrical foil for the front section of the wing. My question is, if possible, am I better off finding a way to designing a wing foil that matches a standard airplane wing foil? More efficient? the Trick is to be able to adjust the leading edge to adjust for left vs. right side attack. Your thoughts?

  10. Chris Drake says:

    Back before computers, they simplified as best they could based on their limited experimental data. We don't need to do that these days. Here's a great example: https://forums.autodesk.com/t5/fusion-360-api-and-scripts/add-in-announcement-hydrofoil-and-airfoil-tools-seeking-your/td-p/9453985 – years of CPU time doing CFD are now free to give you the right shape for what you need, and the math to work out what you need from what you know is now just mouse-clicks away 🙂

  11. Robert Van Housen says:

    Some have suggested this is "Not correct at all", the "at all" part is very unlikely. Also, please give video suggestions for a more complete rendering of the subject.

  12. Magnar Nordal says:

    I'm sorry, but there are too many mistakes here. It starts at 1:15. The stagnation point at the leading edge is shown at the end of the chord line, but with an angle of attack like this, the stagnation point is further down. Secondly, the illustration shows the "equal transit time" hypothesis, which is the result of a poor understanding of Bernoulli's principle. Here is a link to the University of Cambridge, showing how it really works: http://www.eng.cam.ac.uk/news/how-wings-really-work

  13. dnjoncvichy says:

    If these descriptions on video were the reason planes fly, why DC-3 (which has totally symmetric airfoil) had flow and still flies so well… Please don't start explaining with airfoil modern planes don't have…

  14. Observ45er says:

    This video only repeats very common misconceptions and invents a new one, as follows.

    .

    3:13 The low pressure above the wing allows higher pressure ahead of the wing to accelerate it to the higher speed. It is Newton. The force of pressure accelerates the mass of air.

    The movement of the wing creates pressure gradients and as Euler reported to us in the mid 1700s, Pressure gradients accelerate fluids.

    Bernoulli never said speed causes a pressure reduction. He only noted that the (static) pressure and velocity have an inverse relationship with no indication of cause and effect. This is a major, common misunderstanding.

    Euler determined that pressure gradients accelerate fluids toward the lower pressure. That is the opposite of the common misconception.



    3:29 The pressure difference top to bottom accounts for ALL THE LIFT. This 'a little of this and a little of that" is bad science. The same pressures that have the net upward lift force on the wing are the very same pressures that cause all accelerations around the wing including ahead, above, below, behind and around the tips.

    The higher pressure under the wing pushes up on the wing AND down on the air below to contribute to the down-wash.

    The lower pressure above the wing allows atmospheric pressure to push air above the wing downward, to also contribute to the down-wash.

    ..

    NOTE: the whole upward force on the wing is equal to the force required to accelerate all the air in the down-wash. THAT is what satisfies Newton's Third Law. The upward 'push" (force) on the wing equals the downward 'push' (force) on the air accelerated downward.

    The downward moving air does not push up on the wing. That air was pushed down by the pressures around the wing.

    The down-wash also does not push the wing forward. You've invented a new a fallacy. The net force fore-aft is rearward and is called drag and is not caused by the down-wash as explained above.

    When viewed from the still air frame of reference, the down-wash is moving slightly forward.

    ….

    4:27 Bernoulli's Principle is again misused. The flow is not slowed under the wing which is NOT the cause of the higher pressure. . That view is valid only in the stationary wing, wind tunnel reference frame only.

    In fact, REAL data from a REAL wing generating REAL lift flying through otherwise still air shows the lower air being moved forward in the direction of flight. This acceleration from still air is CAUSED BY the higher pressure at the lower surface. The increase in pressure at the surface is because the wing is pushing the air out of its way. This push increases the pressure, not the Bernoulli Principle Fallacy.

    ….

    The pressure increase below the wing in combination with the decrease above the wing provides the ENTIRE lift force.



    If by this magic, the down-wash did just happen to add to the lift, that "addition" would be exhibited as an increased pressure difference on the win…but it DOES NOT.

    Bernoulli's Principle causes nothing in the generation of lift because the "speed-causes-pressures" is a fallacy.

    It is all explained by Newton, BUT NOT with this ":reaction force" fallacy.

    Newton's Third Law "reaction force" is not an originating force, but is a direct result of the originating force which, in this case, is from the pressures around the wing as described above.

    ….

    At 7:11 Please listen to your words: “The high pressure area on the bottom of an airfoil pushes around the tip to the low pressure area on the top.”. This shows that you understand that pressure causes movement, but you fail to apply it on all the other parts of this and, therefore shows the problems with this explanation. The correct story uses this Pressure accelerated air in ALL aspects around the wing, because that I the real science.

    The tip vortex does not ‘create the down wash”. You already explained the down-wash without reference to the tip vortex. This is a flaw in this explanation. The tip vortex is CONSISTENT with the wing generated down-wash moving against the still air outside the wing span. Masses of air sliding along each other create vorticity (vortices) along the boundary of the two masses.



    At 7:47 Winglets DO NOT and CANNOT prevent the tip vortex from forming. They can only reduce the severity and the negative effect because they act to effectively lengthen the wingspan; longer wings have less severe vortices . See Doug McLean’s You Tube video on misconceptions for a full explanation.

    https://www.youtube.com/watch?v=QKCK4lJLQHU



    Though well-meaning, the 'Pilot's Handbook of Aeronautical Knowledge.' has bad information in it as do so many other publications and on-line resources such as YouTube.

  15. Observ45er says:

    +Will Liebhaber,
    .
    This video only repeats very common misconceptions and invents a new one, as follows.

    .

    3:13 The low pressure above the wing allows higher pressure ahead of the wing to accelerate it to the higher speed. It is Newton. The force of pressure accelerates the mass of air.

    The movement of the wing creates pressure gradients and as Euler reported to us, Pressure gradients accelerate fluids.

    Bernoulli never said speed causes a pressure reduction. He only noted that the (static) pressure and velocity have an inverse relationship with no indication of cause and effect. This is a major, common misunderstanding.

    Euler determined that pressure gradients accelerate fluids toward the lower pressure. That is the opposite of the common misconception.



    3:29 The pressure difference top to bottom accounts for ALL THE LIFT. This 'a little of this and a little of that" is bad science. The same pressures that have the net upward lift force on the wing are the very same pressures that cause all accelerations around the wing including ahead, above, below, behind and around the tips.

    The higher pressure under the wing pushes up on the wing AND down on the air below to contribute to the down-wash.

    The lower pressure above the wing allows atmospheric pressure to push air above the wing downward, to also contribute to the down-wash.

    ..

    NOTE: the whole upward force on the wing is equal to the force required to accelerate all the air in the down-wash. THAT is what satisfies Newton's Third Law. The upward 'push" (force) on the wing equals the downward 'push' (force) on the air accelerated downward.

    The downward moving air does not push up on the wing. That air was pushed down by the pressures around the wing.

    The down-wash also does not push the wing forward. You've invented a new a fallacy. The net force fore-aft is rearward and is called drag and is not caused by the down-wash as explained above.

    When viewed from the still air frame of reference, the down-wash is moving slightly forward.

    ….

    4:27 Bernoulli's Principle is again misused. The flow is not slowed under the wing which is NOT the cause of the higher pressure. . That view is valid only in the stationary wing, wind tunnel reference frame only.

    In fact, REAL data from a REAL wing generating REAL lift flying through otherwise still air shows the lower air being moved forward in the direction of flight. This acceleration from still air is CAUSED BY the higher pressure at the lower surface. The increase in pressure at the surface is because the wing is pushing the air out of its way. This push increases the pressure, not the Bernoulli Principle Fallacy.

    ….

    The pressure increase below the wing in combination with the decrease above the wing provides the ENTIRE lift force.



    If by this magic, the down-wash did just happen to add to the lift, that "addition" would be exhibited as an increased pressure difference on the win…but it DOES NOT.

    Bernoulli's Principle causes nothing in the generation of lift because the "speed-causes-pressures" is a fallacy.

    It is all explained by Newton, BUT NOT with this ":reaction force" fallacy.

    Newton's Third Law "reaction force" is not an originating force, but is a direct result of the originating force which, in this case, is from the pressures around the wing as described aboave.

    ….

    At 7:11 Please listen to your words: “The high pressure area on the bottom of an airfoil pushes around the tip to the low pressure area on the top.”. This shows that you understand that pressure causes movement, but you fail to apply it on all the other parts of this and, therefore shows the problems with this explanation. The correct story uses this Pressure accelerated air in ALL aspects around the wing, because that I the real science.

    The tip vortex does not ‘create the down wash”. You already explained the down-wash without reference to the tip vortex. This is a flaw in this explanation. The tip vortex is CONSISTENT with the wing generated down-wash moving against the still air outside the wing span. Masses of air sliding along each other create vorticity (vortices) along the boundary of the two masses.



    At 7:47 Winglets DO NOT and CANNOT prevent the tip vortex from forming. They can only reduce the severity and the negative effect because they act to effectively lengthen the wingspan; longer wings have less severe vortices . See Doug McLean’s You Tube video on misconceptions for a full explanation.

    https://www.youtube.com/watch?v=QKCK4lJLQHU



    Though well-meaning, the 'Pilot's Handbook of Aeronautical Knowledge.' has bad information in it as do so many other publications and on-line resources such as YouTube.
    .

  16. Mateo Brainardo says:

    jihun wong, you are wrong. the airfoil simply redirects the streamlines on the top and bottom, newtons third law applies, and bam; you got lift. Explain to me ground effect, oh wise one…

  17. AbdulRahman Belhareth says:

    Totally reversed. the pressure will be higher above the wing since the area of stream air going through it will be smaller because of the concave shape.

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