In the 4th century BC, Aristotle provided evidence showing Earth was round, such as ships disappearing hull first when sailing over the horizon and Earth casting a round shadow on the moon. Most believers in a flat Earth believe the planet is a flat disk surrounded by an ice wall, and they explain away shorter than necessary flight times by saying they are fake. They use direct Sydney to explain how people can sail or fly in a completely straight line from China to Chile without a slight curve in the horizon.
In theory, you should be able to discern a slight curve in the horizon from an airplane at over 10,600 meters (35,000 feet), although you would need a fairly wide field of view. The topic of air navigation relies on the fact that the Earth is a globe, not the undefined, non-dimensional flat fantasy land they wish it to be. Flat Earthers claim plane routes make more sense on a flat Earth than a globe, but this argument has always been based on how they have been in planes and even from that high up it still looks flat.
Michael Marshall, project director of the Good Thinking Society in the UK, talks about flat earth belief and its relationship to conspiracy theories and other questions. For example, on a flat Earth, the flight route of Jakarta–Hong Kong–New York–Bogota is almost a straight route between the two locations. This page is designed to answer some of the questions that many Round Earthers raise when they first arrive.
📹 Why flights don’t make sense on a Flat Earth
Minor correction – when talking about stall speeds I gave a figure of 250knots, a few people have pointed out this is indicated …
📹 Flat Earthers think planes can’t work on a globe
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Not only do planes work just fine on a globe they use flight plans that will only work if the Earth is a Globe. I have been asking flat Earthers to debate me on this topic for years and they ALL run. One way to silence them is to ask for a flight plan based on an alternative to the Globe and provide the equations used to prove it. They run, every time.
An acquaintance of mine believes in the flat Earth theory. I tried to explain to him that I admire his curiosity and that it’s good to question everything, but that he was still mistaken. I frequently fly from BER to LA/LV, so I recorded articles for him, measured various things on the plane, and took images of the stars and moon in Vegas, among other experiments. However, it didn’t change anything; he wants to BELIEVE in flat earth and it has nothing to do with seeking the truth. I went out of my way for this bs. Now I know the earth is a sphere for 110%, instead of 100%, but he still knows 0.
A simple way to illustrate how that works is to attach a small plane perpendicular to a clock hand. During a full rotation of the hand, the plane also perform a full rotation while remaining perfectly horizontal relative to the up/down direction provided by the clock hand and at the same altitude relative to the clock center.
Excellent article. Just a minor correction, the reason for the difference in pressure is not that “the path is longer” on the upper side, and therefore “it has to speed up”. As you can see from the animation showed also in the article the two separated flows don’t meet up at the end because one is much faster. So it’s not really the length of the foil, but a more complex reason that lies in the particular shape. The best way to explain it is skipping the “length” part and only saying that the airfoil causes a difference of pressure between the upper and the lower surface. Note that this correction DOES NOT change in any way what he explained in the rest of the article, this comment is only meant to avoid common misconceptions about airfoils. EDIT: Btw, thank you all guys, I love that we can all have peaceful conversations in these comments even if sometimes there’s some disagreement, I love when people on the internet just peacefully understand each other’s view. (Yes, that should be normal behaviour, but as you know unfortunately that’s definitely not normality)
As an ex RAF aircraft technician your explanation was fairly detailed and completely correct, well researched Dave, good work. As we know Flerf’s of all abilities are unable and/or unwilling to accept 3 dimensional thinking but people with still functioning “reality acceptance” thinking can easily see the truth to your explanation.
The thing to remember about a plane flying through the air is that it is ALWAYS a battle between keeping it up and falling. The pilots don’t have to lower the altitude of the plane to account for the curvature of the earth, they have to lower the amount of lift needed to keep it up at altitude. Oh, it’s not much, as you point out, and, in the grand scheme of things, it is imperceptible compared to all the other things they are accounting for, but it’s there. A plane is always falling. The challenge is what you have to do to keep it up. Of course, the problem is the whole concept of “tilt the nose down.” Down with respect to what? Down with respect to the surface of the earth? No, you don’t do that. You keep it level with respect to the surface of the earth.
The attitude of the aircraft is adjusting by 1 degree per 111 km. That takes 8 minutes at 450 Knots. Meanwhile the Earth curves by the same amount so there is no apparent change in the nose attitude relative to the horizon. This is very easy to understand for most people but Flat Earthers fail at geometry and physics.
A detail. Planes, sometimes, crash. The natural tendency of any flying object heavier than air is to fall (gravity is the scientific name and description of how all that “things fall” even babies know, works). If anything, pilots don’t correct the position of the plane down to prevent it from flying into space, but correct it in all possible manners to prevent it from crashing against the ground – even when landing.
There is no ‘taking curvature into account’ as I often hear. As a pilot, you level off at your required altitude by setting the pitch attitude to where it should be and see what your altimeter does, then adjust attitude as necessary. Once it flies level at the required altitude, trim the aircraft so all the forces are in balance, then you should be able to just let go and it will stay there. If ever the altitude starts to wander, repeat the procedure. That’s it. It really is that simple, almost as simple as letting an autopilot do it for you. You don’t need to worry about curvature, because as you say, maintaining altitude already does that.
Hey Dave. Airline captain here. Recently found your channnel and love the content. I recently had a visitor to the flightdeck after landing (grown adult) who started with a similar line of questioning. “Hey how do you land a plane on a curved ball?”… “Sorry, what?”… “How do you land a plane on a curved ball surface”… “Well if the ball is big enough the runway is treated as pretty flat”… “Ha, thought you’d say that! So have you ever seen the curve?”… “Well as the globe is so big it’s hard to see unless at very high altitudes”… “right! “… “Ok well our service ceiling, max altitude, is 41000ft and even though that’s pretty high the horizon curve is still hard to see but you can make it out. It’s a gentle subtle curve even at that altitude”… “well, why do they call it the horizon then? Because it’s horizontal! Ha!”… and then he walks off…
Funny that you never hear flat Earthers talk about airplanes making a constant left or right turn as the head east or west on THEIR model… I always explain it this way: Imagine that you’re sitting in a race car on the equator of their flat Earth heading east. How much would you have to turn that steering wheel to stay on that line? The amount would be so tiny that it would seem like you’re not turning the wheel at all. And, once you have it turned you would not need to turn it more since the angle would not change.
This one has always baffled me when I hear it from flat earth proponents. Even if one were ignorant of the sheer size of the planet and how any corrections would be so minute as to be unnoticeable, there’s another good test to show why this is odd and how the flat earth community doesn’t understand the globe earth. Thanks to gravity, everything is pulled toward the center, yeah? If you got one of those tethered model airplanes that you hold via a wire and spin around, where the wire essentially acts like gravity, the model plane isn’t constantly “correcting” for the circular flight. The wire, aka gravity, is doing that for the model plane.
It’s not just flat earthers that get confused with this. I was on a debunking website, can’t remember which, where the owner claimed that the plane does dip it’s nose but it’s automatic and only small inputs are needed. He got quite aggressive when I reminded him that a ship doesn’t need to dip its bow to travel round the earth. Same for a submarine and air, like water, is a fluid.
Hey Dave – I really appreciate all your well-researched, knowledgeable, and carefully explained discussions, especially this one as I’m a small aircraft pilot and see you touched on all the important highlights. And perusal your responses to this entire flat earth business brings up one of my “what if …” fantasies. I’ve thought “What if” I actually won some huge lottery and had money to spare so I could make an offer to the flat earth community; let them pick their most well-known/prominent representative and provide that person with a full “ticket to ride” to the ISS via Space-X. I would think that would put them in a very awkward position – refuse an opportunity to “prove” their position or accept, travel to the ISS, and be forced to concede when they found no wires and likely spend some of their time being space sick because they would be truly weightless. In any case, keep up the good fight.
Also, another thing that shows that curvature of the earth is a real thing can be seen by opening analogue gyroscopic instruments (like the artificial horizon). Since the gyro will remain orientated as the inertial system in which it was started after a few hours of flight you would notice that the instrument is indicating a slightly wrong angle, that’s because the gyro angle reference would still be parallel to the starting position, whereas the plane would be slightly angled because of earth’s curvature (this phenomena is called apparent precession). For this reason the gyroscopic instruments like the artificial horizon have correction systems to turn the gyroscope so that it follows earth’s curvature. This kind of system is in every kind of gyroscopic instrument but on the older analogue ones it’s a physical thing that is attached to the gyro so you can literally see it with your own eyes. Minute 4:40 in: youtube.com/watch?v=b6XzGgOkWtQ Minute 5:55 and 8:00 in: youtube.com/watch?v=aFmq5N4oOc4 (sorry it’s in italian, but you can see the physical thing that’s explained as a drawing in the first article, so the language doesn’t really matter)
As Dave has “stolen” (= already mentioned) most of the numbers that I usually list, just one: This downward pitch correction amount to 1cm/second. Of course, every second another cm from the corrected position. In one hangout, the flatlings came with their usual “the plane would have to dive down 8kms (or so) after 1 hour” – Triumph. Then one of them (might have been Jeran) made the error and calculated the correction after half an hour – oops, just 2 km. Again, 15 minutes – just 500 meters 7.5 minutes – 125 meters. Only then it dawned on him that the square law was just crushing him, and he aborted and kept his mouth shut.
My response to this ridiculousness is to point out that if an airplane has to continually point its nose down to keep from flying off into space, then a boat traveling the same path across the ocean would also have to point its nose down to avoid flying off into air. The same logic applies to anything traveling along what appears to be a straight line on a map.
Does anyone have a curated list of all the people who would have to be brought in on the flat earth secret if it were true? Every national government All world military leaders Every single pilot Every single surveyor Every person who works for whatever agency is guarding the edge of the world Every ship’s captain Every meteorologist ……. Each and every one of them sworn to never reveal the truth and keep acting like the world is a globe, because.. Well, no reason really…
I’ve heard this argument too from a flat earther. Another argument I’ve heard is how do people in Australia stay on the earth. Gravity doesn’t cut it for them. As a cyclist I’m constantly adjusting my balance to keep myself level. However, these adjustments are so slight and so automatic that I’m not consciously aware that I’m doing it. At any rate I enjoy your articles.
I got bored of explaining all this to flat earthers; it didn’t matter that I also pointed out that I’ve had a pilot’s licence for 25 years, work on the things every day and so I know what I am talking about, their Dunning-Kruger self-belief in their notion that they know more about stuff than people with actual knowledge and experience of things, always kicked in. And that’s because they don’t want to be told the truth, they want to think they are special and ‘in on a secret’. They’ll do the same thing with this article too, I guarantee it. Facts mean nothing to those people.
Best flat earth debunking website (as far as I’ve seen). So many of these websites are condescending, and really don’t have more than a rudimentary understanding of what they’re talking about. Dave is only mildly snarky when he gets directly attacked by someone, and he clearly knows his shit. He doesn’t always get everything correct, but mistakes are few and far between. The kicker for me is that I almost always learn something. It might be about aerodynamics, orbital mechanics, or photography, but there’s usually something there. And he’s got really novel methods of attacking arguments which often hadn’t occurred to me. Always a pleasure when he uploads.
You’ve already busted the Flat Earth “model” by 4:00, when you casually mention there being less air at higher altitudes. Flerfers think that it’s impossible to have an atmosphere on a planet that’s surrounded by a vacuum. To do this, they have to ignore actual mountains of evidence (ie- how climbing a mountain perfectly demonstrates the thinning atmosphere with increasing altitude).
Hey there! While i agree of course with the conclusion, the whole aerofoil thing is not the primary reason for why planes fly. Despite that, it is still thought in a lot of physics textbooks and such. If the aerofoil was the primary reason, how would planes be able to fly upside down? The real primary reason in the deflection of air molecules to another direction, thus a change in momentum occurs propelling the plane upwards. Don’t get me wrong, the aerofoil effect is certainly a thing, just not that much of an effect.
I mean they aren’t technically wrong. The plane is going fast enough to cause the plane to have lift… go fast enough and you could lift off the planet. But that’s the wonderful thing about gravity it is still affecting the plane regardless of that lift. So the plane is still falling…. but with STYLE!!!
Airliners also have automatic pilots which keep the aircraft at the desired attitude relative to the continuously measured local vertical. When you initialise an inertial platform when it’s stationary on the ground it uses a set of 3 accelerometers and 3 gyros to level and orient itself. Interestingly, the process is much quicker if you enter your lat and long as then it can allow for the rotation of the Globe beneath it.
What’s kind of cool is that in games like kerbal space program you can let an aircraft fly on its own around and you’ll notice it’s angle of attack very gradually increase as well as altitude until eventually the plane stalls when the speed gets to low. So it’s pretty accurate: so everything once and a while you need to push down the angle of attack. If it were a real plane there would be an autopilot keeping at the same altitude on its own. It’s pretty cool to see actually.
An honest flat earther would consider how they drive a car: do they set the steering wheel to a pre-determined angle and ignore it? Of course not; they constantly play the angle to the response of the car,a little more, a little less. You could unbolt the wheel and re-attach it at some offset and they’d cope perfectly well, because any controlled motion of interest – walking, driving, flying, or sailing – involves constantly integrating multiple inputs and iterating the control in response
One point I think you missed is that airplanes determine their altitude above sea level by using… wait for it… air pressure! So while you’re completely right about the fact that a pilot would naturally be adjusting for Earth’s curvature when also dealing with much larger variations during the flight, I think some Flat Earthers would have this notion that if you set the autopilot to fly “level” then on a globe it should fly on a tangent off into space. But that’s not how autopilots work. When you set the autopilot to level flight, you give it an altitude and it sticks to that altitude. So let’s say it starts off initially flying along that tangent, and 15 miles later the Earth has dropped a 10 feet or so underneath it. But as you pointed out, due to the air pressure gradient, your air pressure a 10 feet higher is now slightly lower. The autopilot will read that as now being at a higher altitude than it was before — which it is — and pitch down slightly to return to the designated air pressure target.
Man, I saw a article where a pilot provided what he considered to be compelling evidence for flat earth. I, not knowing anything about aviation, started to get a little stumped by what he was saying. I am so glad I saw this article. You totally debunked his argument with simple clarity. Part of the reason I struggled dealing with his article was there were some many overly complicated things to try to follow. Thank you for your time and efforts.
No correction for curvature is needed because flying a great circle course there is no change in altitutde or attitude from moment to moment. H above SL is always the same. The problem with flat earthers seems to be their inability to viualise altitude as a distance above the centre of the globe… a radius in fact. Buu then it seems that the idea of gravity is difficult for them too. Looked at from “outside” where there is no up, down or sideways, it is obvious, but it seems to be a fact that some people cannot visualise it. That doesn’t make the facts different, it just makes the flat earthers not very bright.
If you wanted to try extend out the flying in a tangent to earth, you could use simple physics and trig to show that once the plane is farther out on its tangent, the vertical vector of gravity has shifted in relation to the lift vector, causing the vertical vector of lift to be angled in relation to gravity, so you start to fall toward gravity because the vectors don’t balance out anymore. Unless you increase lift which means increasing speed. Which leads to the horizontally increasing speed to eventually be the vertical vector as the plane reaches 90 degrees to its original starting point, which is just a diagram of a rocket pointed straight up.
Planes fly level to maintain altitude. Level comforms to the distance to the center of earth not the geography of earth. Understanding this simple principle completely eliminates the stupid idea of it must nose down to stay level. Level dosent and has never meant flat. If you think it does, you should put on a helmet to protect your silly brain
Alright let’s calculate the angular change required to keep a plane level as it travels around the globe. If a plane travels around the world along a great circle arc, it has to rotate 360 degrees, which means the amount it has to rotate is equivalent to the radial distance around the planet. The earth is 10,000 km from north pole to equator, so 40,000km circumference (give or take since the earth isnt exactly circular). 360 degrees over 40,000km is 0.009 degrees per kilometer. Long distance planes fly at about 900kph, meaning that every hour you rotate 8 degrees. The hour hand on a clock rotates almost 4 times that speed and if you look at an hour hand it doesnt seem to be moving at all. Throw in the fact that plane noses are constantly going up and down slightly to adjust for different wind speeds, weather, turns, etc and it becomes completely impossible to even notice the turn
Flerfers try to use the argument that commercial flights don’t fly over Antarctica, not realising that the actual reason commercial flights don’t fly over Antarctica these days is because of the Mount Erebus air disaster of 1979, where it was virtually impossible to rescue anyone because of the remoteness of Antarctica.
You do a great job at explaining some pretty complicated physics in a way that everyone can understand. Or at least in a way that everyone with an IQ above 70 can understand. I’m not sure there are any flerfers with an IQ that high, to be honest… If a flerfer truly believes their nonsense about airplanes having to constantly “nosedive,” then why don’t they send one of their own to flight school and get them employed as a commercial pilot? They could test out their hypotheses in person that way — preferably on a cargo flight rather than a passenger flight, of course. I guess the problem with that is that you have to be able to understand some of the physics of aerodynamics and some moderately complex maths in order to get a pilot’s license, so the flerfers would all flunk out of flight school…
An aircraft in the cruise will be maintaining a steady pressure altitude, either under control by the pilot or the autopilot. And yes, it will have to continuously pitch downwards in order to do that. But the pitch rate will be so slow as to be completely imperceptible to anyone – including the pilot. Think of it this way: For a subsonic aircraft, it will be pitching down at less than half the rotational rate of the hour hand on an analogue clock. Sit and look at such a clock for a while and see if you can perceive it moving. You can’t. And then realise that the aircraft pitch rate will be half that. (I’ve spent my career in flight simulation, global navigation, ATC, and Safety Assurance, and I have plenty of experience in that field. I have flown as a pilot and a passenger throughout that period. I know for a fact that all aircraft navigation is calculated based on the Earth being a globe.)
Seriously, I don’t think flat earthers actually believe what they say they do. I think they’re just trolling and enjoying the attention and income they are able to generate by vigorously arguing for a position they don’t actually hold. Like debate club in high school, except if they do it right they get paid well for their efforts.
Im not kidding about this. I was a sophomore and flat earth had a little spike in trends. We were talking about space and astronomy and this kid said that if the earth was a ball how come he can roll a ball and it stop. He was legitimately making the argument that since its round the ball should never stop. He also made the argument that there is an ice wall with a firmament overhead. I asked him about meteorite’s and lunar eclipses and his whole argument fell apart
Nice one Dave, I especially liked the ‘from the plane’s perspective’ graphic. Now all we have to do is wait for Oakley to rip this one apart in one of his FEDs by interrupting, insulting, and shouting midway through every non-technical/non-relevant sentence that you made. “CLOSED SYSTEM YOU *%£$!!”$%^ “
flat earthers think the entire earth is the size of just the USA they think california is on the underside of the world, and they think for them to reach upside down by the time they reach california they’d have to nose dive this, of course, makes no sense, so they think the entire thing must be flat
If the earth is a flat disk being propelled upwards to simulate gravity, what keeps the air from being blown off (especially around the edges) allowing planes to even fly at all? Where is this atmospheric regeneration coming from? Further, why isn’t the upward moving earth constantly smashing planes like bugs on a windshield?
Ask them how it is possible that, according to their perspective, we don’t have to constantly steer the airplane to the left or right, since the east and west is also a circle on their flat disc model. When we travel to the east or west, we moving in a straight line. Considering their claim that the North is at the center and the South at the outer edge, according to their model, if we were to travel in a straight line, we would consistently end up in the South!
I’m truly not interested in anything flatties have to say. But I wanted to say that I’ve seen the sun rise while on a flight to Saudi Arabia when I was a kid. That beautiful dark red to orange to yellow and to blue, then dark blue in the sky as we flew at 35000 feet, combined with the gorgeous strong curvature of our Earth is the most wonderful, beautiful, exquisite thing I’ve ever seen in all my seventy years! 🥰 I’ll never forget it, and I hope it’s the last thing I ever remember when I die. 🌅🥲
Excellent description of how a plane works. However, it doesn’t matter. Flat Earther’s cannot comprehend that down is relative. They believe that down is a universal constant which is why they think people in Australia are upside down on the globe model. This means that they don’t think the atmosphere wraps around the earth, they just believe that the air starts at the bottom of down and goes up until it doesn’t. So even after this excellent description, they don’t understand how an airplane can curve around a globe without pointing their nose down, and eventually flying upside down.
Flerfers are simple-minded creatures who think north, as illustrated on a typical globe, is the “top” while south is the “bottom”. Therefore, they think when a plane flies from north towards south, the plane is diving “downwards”, eventually going upside down. They simply can’t comprehend the fact that the universe has no “up” and “down”.
The problem with refuting flerf points is that their issue begins more fundamentally than any singular point: Their standard of evidence. If you want to make any headway with a flerfer, you need to begin with agreeing on a standard of evidence and remaining true to that standard for everything. I suspect they will be unwilling or unable to do so.
Aircraft altitude is measured (inferred) by atmospheric pressure. The aircraft is usually flown at an altitude that maintains constant ambient pressure (by pilot or autopilot, as the case may be). Changes in local barometric pressure (provided by air traffic control) are used to recalibrate the aircraft altimeter. As long as the aircraft is flown at a constant ambient pressure (hence constant altitude), it will be following the earth’s curvature (as the atmosphere is attached to the spherical earth and has same properties at same distance from the centre, in an ideal case) as the altitude is measured from the surface, which is curved, and not a plane.
Can’t wait for the flerfs to just… see your detailed explanation as to why they’re absolutely incorrect about aeronautics, or whatever it’s called. Then proceed to claim “nope nope nope the animation is true it has to nose dive” when they forget that gravity would still be pulling them down and they wouldn’t be flying fast enough to eject from the atmosphere.
It does drop thousands of feet during the flight, just thousands of feet from the point of view of the start of the flight. In other words if you drew a line straight out tangent to the ground at the start, there would be thousands of feet of space between the line and the ground at the end because the Earth is round
Of coarse the energy used taking a plane up would slow it down well before the air thinned significantly. The plane would slow down reducing lift and fall back to it’s trimmed altitude. Because the downward curve is so slight and self correcting, these adjustments are lost in the noise of correcting for wind gusts, control play, etc.
This is the perfect, in-a-nutshell, kinda concept that really does a good job of illustrating flerthers biggest problem. That David Weiss from d.i.r.t.h. or whatever has gotten pretty animated at the idea of aeroplanes doing multiple controlled glides, like a flying squirrel (or using an elytra in Minecraft without any rockets), to travel for as long as possible whilst making huge vertical alterations to its pitch. And they disbelieve that premise because it’s ridiculously large but also cannot accept that a 0.002° trim is a realistic adjustment either. 🤷🏻♂️
Do they really also not understand how much energy is needed to increase altitude relative to the ground? As you try to go up, you’re fighting against gravity- if you can just fly straight in a tangent line without any problem then getting to space wouldn’t require absolutely massive rockets to overcome gravity. It’s like thinking driving a car on the surface will lift you off of the ground – and It’s like if you are looking at the orbit of a spacecraft around the earth and you just expect to go in a straight line, if you have no perception of the speed you already have and that your angular momentum will stay constant with gravity pulling you evenly across a circle at the same distance (assuming non elliptical orbit). In an orbit, in order to go in a straight line, or to expand the circle you would need lots and lots of energy to push yourself against gravity and momentum – and this thing with the plane would be like assuming you can increase the height of your orbit by flying perpendicular to it and not in the same direction of it – like how they do in movies (side note, I feel like flat earthers get all their intuition about the world with how things in movies work, it’s like if you showed them an actual explosive detonation and they said “thats not real because there wasn’t a big fireball”)
A typical passenger Aircrafts centre of lift (COP) and Centre of mass (COG) are not in the same place… COP is always behind COG to provide static stability for the aircraft. This means that gravity alone and its contstant changing angle relative to the earth as you move forward would inherantly and constantly level the aircraft by how it is balanced… and means no trim change would be required to combat it.
If you’ve ever flown a plane, you know that you would NEVER be able to notice having to pitch down to keep with the curve of the earth. As stable as an airliner seems, they are pitching and leaning and weaving all over the place all the time. So you’d technically adjust for the curve of the earth, but you wouldn’t be able to tell even if the earth were half the size.
Ok. . . Need to toss this out, as it’s a slight pet peeve of mine. Lift is NOT caused by lower pressure on top of a wing as opposed to below the wing! At least not a vast majority of it anyways. Lift is actually produced by the curved surface of the top of the wing causing the air flowing over it to divert downwards relative to the direction of travel. This downward movement of air produces an equal but opposite effect of pushing the wing upwards. Direct enough air down, and you soon create enough opposite force upwards to lift the entire plane. That’s why speed is needed. That’s why flaps are used at slow speeds. Let the arguments commence. . . 😉
As someone who’s been into aircraft and aerodynamics for more years than I care to remember, you’ve explained the basics of aerodynamics and flight fairly accurately, and why aircraft don’t fly upside down when flying long distances and why aircraft don’t have to push the nose down all the while. Anyway, although I think this is fairly simple stuff it’s still too hard for a flerf to understand, what’s the betting that the flerf community will still push their very wrong narrative even after your easy-to-understand explanation of flight, well done Dave, well done.
Related in principle to the FE theory of having to continually nose down during flight. If you position a globe on its side and look down the line of the of longitude and rotate the globe, you will see that it is a straight line of path. It does not curve and you do not have to adjust your path of flight from a straight ahead direction if you are in an aircraft flying along that line. It may appear not to be true initially thinking of it, but a simple visual test proves my observation is true. An aircraft starting at one point on any line of latitude will remain on that line and will not “drift North or South” at all. It’s position in relation to the poles does not change at all. That is what the lines of latitude are for!!! They are a measurement of distance from the poles. On a flat Earth, the lines curve and an aircraft has to make a continual adjustment to stay on it. You can even test it to prove it. For this test you need to move the aircraft or a model of it over the Earth of the model of it and you will see that with a globe you can even hold the model plane in one place and rotate the model Earth and you get the same results. With a flat Earth model that only appears to work if you hold the model stationary and rotate the model Earth. When you move the model aircraft in the flat Earth test you must turn the aircraft the entire time that you move it over the line of latitude. And that is true even at the equator of the flat Earth and not at all on a globe model. The Earth.
If you made a small wooden model of a plane and screwed an eye screw into the underside at its centre of gravity, it could hang from a piece of string and be perfectly level (although upside down). If you then spin the plane around in a circle while holding the string, it will always be level with respect to the centre of that circle. There’s no need to adjust the trim. The forces acting on the model are basically the same at every point on its path. Aeroplanes in level flight are always level with respect to the centre of the Earth.
I’ve had this discussion with a lot of flatearthers on Quora, but I generally skip mechanics of flight mentioned in the first part of this article, because I know very well that it would go over their heads, especially when written as text. So I generally skip to the simpler explanation, like in the latter part of this article, and I basically just tell them that the pilots have to adjust their altitude constantly, and that they’re not going to accidently fly off into space. I do also try to get the idea of potential energy and equipotential surfaces across to them, and explain that for a plane to climb an extra 5,000 feet would require additional energy, in the same way that it takes more energy for a person to walk up a set of stairs, than it does to walk across a room. I rarely get many coherent responses to these answers, which usually means that the flatearthers in question are probably stumped. But of course I do often get some incoherent responses from them, mostly CAPS LOCKED answres wit SPELliNg mustkeis ndsumabuuse and threatz.. Which are always fun to read..
I did the math to scale down the globe for a flat Earth page and got yelled at. A 6ft 6inch tall man is roughly 2000 milimeters. And if we shrink him down to 1 milimeter tall. We shrink everything else by 2000 also. The circumference of that Globe would be (roughly) 12 miles. Mount Everest would be 14 ft tall. A commercial plane would fly at 21 ft at less than 1 quarter of a mile per hour. And that Earth’s rotation would be half a mile per hour… But a flat earther will tell me that I don’t understand physics. Well I don’t claim to know anything about physics! This is simply about scaling
Dave: I was so glad to see you show the part where the plane was stationary at the “top” while the Earth rotated under it. To me that one point demonstrates that many Flat Earth believers cannot think beyond their simple reference frame, thinking that if Earth is a globe then North has to be “up” and South must be “down”. They start with a false assumption, claim it doesn’t work, only “their way” is The Truth. 🙄🤦♂️
There is absolutely no need to correct an aircraft for the curvature of the Earth. Any and all aircraft have a ceiling or an altitude above which it cannot rise due to its limited thrust which translates into velocity. So no matter what the pilot does it will get stuck at a certain altitude depending on the velocity of the aircraft.
Dear Dave, I’m sure I’m not the first person to tell you this, but you’re eplaination of lift is incorrect. I don’t particularly blame you, as it’s a very common misconception, even in some physics textbooks. The explanation you gave, commonly referred to as the “equal transit time” explanation, relies on the assumption that a fluid(in this case air) passing by an aerofoil must take an equal amount of time to transit over and under the surface, and thus causing a drop in pressure due the longer distance. This has been repeatedly been proved to be incorrect. Lift is instaid generated by the foil pushing air downward, and via Newton’s 3rd law, the air pushed back up on the aircraft, generating lift. This obviously doesn’t really have any impact on the main point of the article, I just figured it was something worth pointing out. Appreciate all the work you do! -James
From a pilot I know. Aircraft fly altitudes and levels, not constant, linear paths. They’re constantly adjusted to maintain a particular altitude, but over the great circle routes, it is so minor as to be imperceptible. As such, in small craft, over small distances, there is no correction required or made. As to speed.. Aircraft measure it in indicated (relative), true (indicated adjusted for density of air and temperature), and ground speed (true adjusted for winds aloft), not “orbital”. So, another good article @DaveMcKeegan.
FWIW: I am currently rewatching this article. As I have commented under at least one other of Dave’s articles, everyday hundreds of thousands of people fly across the world. Perhaps MILLIONS, or even TENS OF MILLIONS. With all those people flying in all those aircraft, there is not one verifiable article or photo of the ‘Ice Wall’ at the edge of the Flat Earth.
Not to mention that modern airliners use auto pilots for most of the flight, usually only flying the first part of the take-off and only the final approach and landing by hand, so these airliners have t he ability to trim themselves to maintain level flight. Ya know, flat earthers could just go to their believed edge of the earth and their solid “firmament” many also believe in, and just take pictures and articles to prove us spherical earthers wrong, but none have ever done so. I also know a 747 pilot who is willing to fly a plane around the world with flat earthers on board and any instruments they want to bring with them to verify the direction of flight, as long as the pay the charter fees for the use of the aircraft and fuel. To date, he has not had any flat earthers take him up on that offer.
Good article. Your diagram of lift would be more accurate if the arrow was under the wing not over, because it’s the atmospheric pressure below the wing that holds up the plane. The lower pressure above the wing does not pull it upwards. Low pressures and vacuums have no power to pull or suck on objects or air
I love the way you explain things Dave. You have such a natural intuition about how to cover every aspect a person can think of to ask questions about. It’s sad this stuff needs to be explained to grown ass adults, some with their own children (😳), but it is what it is I guess. Thanks again, Dave! 👍🏻
Also, check me if I’m wrong, but doesn’t the weight of the plane behave like a centripetal force? It’s like tying a rocket to a string that’s staked to the ground: once the string goes taut, the rocket will just go in a circle without needing to adjust the thrust angle, because the tension in the string changes the rocket’s direction anyway.
As always the best debunker, especially the points you brought up at the end, and those are the KEY! Too many people get all caught up in the stuff that you were mentioning at the beginning and never go on to touch on the the REAL reason pilots aren’t constantly and consciously pitching down to follow the curvature. The earth curves away a whopping 8 INCHES per mile. Now the squared part of the equation only factors into an observer at the starting point. From the pilot’s perspective it’s always just going to be just another 8″ drop for the next mile they travel. Now each mile takes 7 to 30 seconds to travel, depending on the aircraft. There isn’t a pilot on the planet that can maintaing altitude within 8 inches for 7 or 30 seconds. Not only can’t they control it that precisely, they can’t see it nor is it indicated on any altimeter. Altimeter’s don’t have INCH indicators. As you mentioned ALL the variables involved in flight cause the pilot or autopilot to continually make minute corrections to keep the aircraft at their assigned altitude(really pressure level, as that is what the altimeter senses). So the pilot has no idea when he’s making a correcting control input if it’s adjusting for ANY of the variables in flight or the 8″ dropoff from the earth’s curve. Think of an automobile. I don’t care how straight and flat the road is, how perfectly aligned the car is or perfectly inflated the tires are, try taking your hands off the wheel for 30 seconds and see how that goes for you.
Changing the subject a bit, I thought of a new potentially novel way of proving earth’s curvature. Have you ever heard flat glass being referred to as float glass? There’s a reason for that. The cheapest way to produce flat sheets of glass (this is a bit simplistic, but is literally true nonetheless) is to have the glass literally float on top of a molten pool of tin. Tin has a high enough boiling point to not flash into tin vapor when introduced to hot molten glass, yet has a low enough melting point to not freeze as the glass solidifies. This means two things: 1 float glass is REALLY flat and smooth for a mass produced material. It’s commonly used instead of a proper surface plate (a literal standard of flatness to ensure accurate precision measurements are made) when a super accurate standard isn’t required. 2. The molten tin pool must have a curved surface due to the influence of a spherical objects gravity, aka the earth. Therefore, float glass must as well, as it derives its shape from the same pool of molten tin. The problem with this is manifold. Firstly, float glass is rather thin, it probably isn’t stiff enough to retain measurable amounts of the earth’s curvature compared to the curvature of it bending under its own weight. Secondly, the curvature will be so slight that internal stresses would distort it beyond the ability to measure the earth’s curvature. Lastly, I have no idea how to surpass these difficulties or conduct a sufficiently rigorous experiment. I might suggest this to
I think my new favorite argument against Flefs is when they say things should fall off the “bottom” of the earth, ask them to explain what’s the supermassive object that’s attracting them. And when they get confused, assert that “stuff doesn’t just fall towards nothing.” See, what they’re doing there is trying to apply a version of the laws of physics that only works on a flat earth to the globe. By interpreting their argument with actual globe physics, you turn their own stupidity against them.
Flat earthers would have you believe that aeroplanes naturally fly perfectly straight like a laser beam if no adjustments were made. Even without updraughts, air pockets, or crosswinds it would still be impossible and there would have been no need to invent autopilot. Here’s an experiment you flatties can try. Find a straight stretch of road, get your car going as straight as you can, keep the steering wheel in the exact same position, and see how long it takes to run off the road and crash. Better still, film it. We’d all get a good laugh!
As an ex glider pilot I feel qualified to comment. Aircraft are trimmed to fly at a more or less constant speed and pitch. When correctly trimmed this alone is enough for them to maintain a more or less constant altitude and follow the curve of the Earth. However an out of trim aircraft may require the pilot to hold in some up OR down elevator (depending on which direction the trim is off) to maintain constant height. So although pilots dont have to consciously “dip the nose” every now and then as flerfers claim, the controls, including trim, are being used to follow the curve of the earth. Air pressure variation with height isnt really enough to be self correcting, although it would be near the altitude limit for the aircraft. In short, If you could somehow transport an aircraft to a flat world the trim would need to be ever so slightly adjusted. This ignores the bigger problem flerfers face – which is that gravity woudnt point downwards except at the centre.
So like on Pizza World a boat going straight from east to west on the equator has to constantly steer in one direction to follow it. And in that case they do not have gravity that pulls the boat towards the North Pole creating a curved path without having to counter it like it is with planes. But I assume flat earthers will argue that it’s the magnetic force of the North Pole that draws the boat towards the North Pole. 😅
So, what happens on a flat earth if a plane continues to fly straight and doesn’t change its heading? It flies over the ice wall and then what? Could it then fly beneath the earth so we could see what the underside looks like? How thick is this pizza earth? Is it a thin crust or a Chicago style deep dish? Could a hole be dug through it and if you fell in, you’d fall out the bottom into space?
I like learning about the things you talk about, i feel like im learning more from you debunking flat earthers than i did in my engineering classes, i always had aerodynamics explained to me in a much different way about how the drag levels at different angle’s influence the amount of lift lade but i was never given visuals that helped me really understand it, thanks for this free lesson 🙂
The latest flerf argument that I have seen was that the attitude indicator should be thrown off due to the Earth’s curvature. They then denied that pendulous vanes, used as corrective mechanisms on attitude indicators, could work to correct the deviation. Because apparently pendulums do not function based on gravity. This person is an air traffic controller.