No One Can Explain Why Planes Stay In The Air

Ed.'s note: We have an essay posted below after this Scientific American article that might explain how aircraft stay in the air since the Scientific American seems unsure. Next our scientist priest class whitecoats will be telling us they don't know why ships float. Note that Scientific American uses a really neat looking graphic of a Lockheed Martin SR-71 on their website. If Lockheed Martin had this technology for the SR-71 in the 1950s, where is all this technology today? Testing it out over the Antarctic where there is cold air for optimum performance? Bet they know how aircraft stay in the air. Like fly into deep space.
________

Source: Scientific American

Do recent explanations solve the mysteries of aerodynamic lift?

By Ed Regis | February 1, 2020

• On a strictly mathematical level, engineers know how to design planes that will stay aloft. But equations don't explain why aerodynamic lift occurs.
• There are two competing theories that illuminate the forces and factors of lift. Both are incomplete explanations.
• Aerodynamicists have recently tried to close the gaps in understanding. Still, no consensus exists.

In December 2003, to commemorate the 100th anniversary of the first flight of the Wright brothers, the New York Times ran a story entitled "Staying Aloft; What Does Keep Them Up There?" The point of the piece was a simple question: What keeps planes in the air? To answer it, the Times turned to John D. Anderson, Jr., curator of aerodynamics at the National Air and Space Museum and author of several textbooks in the field.

What Anderson said, however, is that there is actually no agreement on what generates the aerodynamic force known as lift. "There is no simple one-liner answer to this," he told the Times. People give different answers to the question, some with "religious fervor." More than 15 years after that pronouncement, there are still different accounts of what generates lift, each with its own substantial rank of zealous defenders. At this point in the history of flight, this situation is slightly puzzling. After all, the natural processes of evolution, working mindlessly, at random and without any understanding of physics, solved the mechanical problem of aerodynamic lift for soaring birds eons ago. Why should it be so hard for scientists to explain what keeps birds, and airliners, up in the air?

Adding to the confusion is the fact that accounts of lift exist on two separate levels of abstraction: the technical and the nontechnical. They are complementary rather than contradictory, but they differ in their aims. One exists as a strictly mathematical theory, a realm in which the analysis medium consists of equations, symbols, computer simulations and numbers. There is little, if any, serious disagreement as to what the appropriate equations or their solutions are. The objective of technical mathematical theory is to make accurate predictions and to project results that are useful to aeronautical engineers engaged in the complex business of designing aircraft.

But by themselves, equations are not explanations, and neither are their solutions. There is a second, nontechnical level of analysis that is intended to provide us with a physical, commonsense explanation of lift. The objective of the nontechnical approach is to give us an intuitive understanding of the actual forces and factors that are at work in holding an airplane aloft. This approach exists not on the level of numbers and equations but rather on the level of concepts and principles that are familiar and intelligible to nonspecialists.

It is on this second, nontechnical level where the controversies lie. Two different theories are commonly proposed to explain lift, and advocates on both sides argue their viewpoints in articles, in books and online. The problem is that each of these two nontechnical theories is correct in itself. But neither produces a complete explanation of lift, one that provides a full accounting of all the basic forces, factors and physical conditions governing aerodynamic lift, with no issues left dangling, unexplained or unknown. Does such a theory even exist?

TWO COMPETING THEORIES

By far the most popular explanation of lift is Bernoulli's theorem, a principle identified by Swiss mathematician Daniel Bernoulli in his 1738 treatise, Hydrodynamica. Bernoulli came from a family of mathematicians. His father, Johann, made contributions to the calculus, and his Uncle Jakob coined the term "integral." Many of Daniel Bernoulli's contributions had to do with fluid flow: Air is a fluid, and the theorem associated with his name is commonly expressed in terms of fluid dynamics. Stated simply, Bernoulli's law says that the pressure of a fluid decreases as its velocity increases, and vice versa.

Bernoulli's theorem attempts to explain lift as a consequence of the curved upper surface of an airfoil, the technical name for an airplane wing. Because of this curvature, the idea goes, air traveling across the top of the wing moves faster than the air moving along the wing's bottom surface, which is flat. Bernoulli’s theorem says that the increased speed atop the wing is associated with a region of lower pressure there, which is lift.

Please go to Scientific American to read the entire article.
________

LIFT on a Wing

plus a discussion of buoyancy 

and the raindrop question

by Miles Mathis

First published February 4, 2012

Almost no question has caused such incredible piles of nonsense-answers over the centuries as the question of lift on a wing. It has puzzled scientists for millennia. Aristotle and other Greek philosophers theorized on the subject in the 4th century BC, and Leonardo did famous work on the problem in the 15th century. In many ways, their explanations were more coherent than what we have today. You can see this by going to Wikipedia. I encourage you to read the entire page closely, scanning for sense. You won't find any. I will be told that this is because the science pages at Wikipedia are written by pimply-faced highschool boys who can't get dates, but they aren't. They are written by the universities and other institutions, which means they are written mainly by pimply-faced guys in their 30's who can't get dates.

For most of the 20th century—and the 19th and 18th centuries as well—the primary answer to this question included Bernoulli's Principle, and the old lift, drag, thrust, and weight vectors. Unfortunately, that lift vector has always been a hanger, and when it comes time to explain it, the hemming and hawing crescendoes, the math takes over, and everything possible is done to deflect you from noticing that the question is not being answered. It is also unfortunate for those selling this theory that it basically crashed in the 20th century, when it became possible to photograph smoke traveling past an airfoil in a wind tunnel. We had been told that the air above traveled faster than the air below, due to the fact that there was more curvature above, and that this created lift. It was not clear how this created so much lift in the first place, but even that has turned out to be false. Or, the air does travel faster above, but it appears to have nothing to do with the shape of the wing. From the photos, we know that the air above travels so much faster than the air below that they don't even come close to meeting at the back of the wing, which destroys all the old assumptions and equations.

We see this immediately in a recent "One-minute Physics" segment at New Scientist TV. The scientist, Holger Babinsky, admits that the old explanation has been falsified in wind tunnels, but he continues,

Babinsky explains that, although lift is caused by a pressure change between the top and bottom surfaces, it's due to the change in the shape of the air flow, rather than its speed. "This is why a flat surface like a sail is able to cause lift," he says. "In this case, the distance on each side is the same but it is slightly curved when it's rigged, acting like an aerofoil."

You see that he has deflected into curvature rather than different lengths top and bottom, but this explains nothing. First, notice that Babinsky completely overturns more than 200 years of bedrock theory and no one blinks an eye. New Scientist sells it as a One-Minute soundbite, and we are supposed to go on with our business, thinking that the old physics has just been given a minor update. No problem! It is still a pressure change, so who cares? But also notice that Babinsky hasn't shown us exactly how the shape of the airflow causes lift. He just states it as a fact. One of the commenters does the same thing. James says, "air above the wing moves faster on the top and the pressure is lower over the top because of that." But neither the speed nor the shape can cause more or less pressure without a mechanism. We have never seen a mechanism.

Here is the closest thing we get. The dots stand for air pressure, we have more dots below, therefore more air pressure, therefore lift. Many problems here, though. One, the diagrammers commonly give the wing an angle of attack in these newer animations, which is cheating. The old diagrams didn't do that. Two, we can turn the wing over and get lift, so we know it isn't the the longer distance on top that is causing the faster flow on top. So what is? Three, this diagram is pushed in another way, as we see by the rising dots even before the air reaches the wing. What makes those green dots in the second division rise before they reach the wing? Four, if the given mechanism worked as we are told, the back of the wing would be lifted more than the front. This diagram suppresses the fact that a change in speed requires a period of acceleration. If the higher speed above is causing the lift, then lift should increase as the speed increases. Since we must have a period of acceleration, the front of the wing would feel less lift than the back. This problem is never addressed. Five, the front of the wing has more weight, which doubles the problem of four. The back of the wing should have more lift and less weight, therefore we should have a strong torque on this wing, forcing the nose of the airplane down very strongly. We don't. Six, pressure changes like this still wouldn't cause a huge vector up. Some vector up would be created, but we have never been shown any clear math that proves the vector is capable of lifting giant planes into the air. The air density, especially at higher altitudes, isn't that great to start with, and the density differentials across a few feet cannot be that great, no matter the thrust. As usual, the equations are just matched to the data. We know that huge vectors up are created, so it must go to air pressure differentials. What else could be causing it?

We should have known that the old equations were compromised long before Babinsky admitted it, since we had known since the early part of the 20th century that planes fly just as well upside down.

According to the old math and theory, this shouldn't have been possible. To answer this, current physicists (and others, like Simple Cecil) deflect you into "angle of attack," which is a truly pathetic dodge. As you will see below, they deflect you into angle of attack even when they aren't explaining inverted wings. But it doesn't answer in either case, because we get lift in both cases without any angle of attack. We get lift even with negative angles of attack, in both cases; otherwise planes would either climb or drop like rocks. Those would be the only two possibilities. As soon as they leveled out or began a shallow descent, they would lose all lift and plummet. But they don't do that. We know that inverted planes can perform shallow descents, which immediately kills the idea of lift being caused by angle of attack. We know that inverted planes can fly on a level. If it were angle of attack that was causing lift, inverted planes could do nothing but climb.

See, no angle of attack. That top plane should have no lift, according to current theory. No angle of attack, wing not angled, wing with almost no curvature top or bottom, plane itself with more curvature down than up.

The same applies to a wing in the normal position. If you go to AskaMathematician.com, and ask him this question, you are treated like an idiot. He tells you,

Using the engines we have today (jets and what not) you could fly a brick, so long as the nose is pointed up.

Dodge. You see that this implies angle of attack is what is important. He wants you to think that, because all the old answers have fallen apart. But if you aren't an idiot, you remember watching planes take off. Planes taking off have no necessary angle of attack.

That plane weighs 775,000 lbs, and as you can see for yourself, its nose is not in the air. The tail is higher than the nose. The wings are sweptback, but they are not angled. And the engine placement should also interfere with the given theory of lift, since its exhaust acts to speed up the air on the lower side of the wing. And yet, if you move that plane fast enough in that position, it will take off.

That plane weighs 775,000 lbs, and as you can see for yourself, its nose is not in the air. The tail is higher than the nose. The wings are sweptback, but they are not angled. And the engine placement should also interfere with the given theory of lift, since its exhaust acts to speed up the air on the lower side of the wing. And yet, if you move that plane fast enough in that position, it will take off.

No angle of attack is necessary. We know this because very fast cars on the Bonneville salt flats take off if measures aren't taken to keep them from taking off. Not only do they have no angle of attack, they have no wings.

I will be told that this plane's thrust is so high it can overcome any problems, so let us look at a smaller plane:

Again, tail higher than nose, wing not angled.

I will be told that airplanes taking off do have their noses in the air:

Do you see the problem with that argument? It was lift that put the nose in the air, so the nose in the air can't be causing the lift! That would be circular, no? We can't have A causing B and B causing A. Do you think the pilot just pulled back on his steering wheel and the nose jumped up into the air, causing an angle of attack? I don't think so. This plane is already taking off, so lift is already happening. To study the cause of lift, we have to study the plane before it is taking off. And in that case, it is level to the ground.

I will be told, "The pilot uses flaps to get the nose in the air, you moron," but that answer misses the point. The flaps simply divert the lift that is already occurring to the front, instead of to all parts of the plane equally. So, again, the lift is the cause, not the effect. Without lift, the pilot couldn't get the nose in the air, so the nose in the air can't cause the lift.

But none of this matters. It is all a diversion, as I already proved above. If angle of attack worked as we are told, then airplanes wouldn't be capable of shallow descents. As soon as the angle of attack went negative, the lift would go negative and the plane would plummet. Lift has to remain hugely positive even during a shallow descent, because it is still counteracting most of the weight of the plane. If lift goes to zero, we are left with only the down vector, and a fast crash. This argument is doubled with inverted planes, which are also capable of shallow descents. They are supposed to be relying completely on angle of attack for lift, so any negative angle should cause negative lift. The inverted plane put at an initial shallow angle should immediately fall even faster than a rock, since it now has two stacked vectors down (weight and lift).

Modern physicists and mathematicians seem to understand the jig is up, since they don't even pretend to try to make sense anymore. The desperation has become obvious, and you can almost see the sweat poring down their faces as you read their remarks. Our mathematician at AskaMathematician.com is proof of that, since this is his last of four paragraphs:

So to actually answer the question; back in the day planes couldn't fly upside-down. But since then engines have become powerful enough to keep them in the air, despite the fact that by flying upside-down they're being pushed toward the ground. All they have to do is increase their angle of attack by pointing their nose up (or down, if you ask the pilot).

Weird. First, he admits that he hasn't "actually answered the question" in the first three paragraphs, then he misuses a semicolon, then he tells you a lie. "Back in the day," planes couldn't fly upside down. Hmmm. Maybe by "back in the day," he means before airplanes were invented, which is the only way he can be seen to be right. Because according to the old films I have seen, and the old planes I have seen fly recently, the old slow-moving planes were about the easiest to fly upside-down of any of them. Planes have been flying inverted almost from the beginning. Maybe our expert mathematician hasn't seen The Great Waldo Pepper, where Robert Redford's character spends half the film flying his 1920's era Standard J-1 upside down. I would call that back in the day.

Please go to Updates to read the entire essay.