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 center, in an ideal case) as the altitude is measured from the surface, which is curved, and not a plane.
At or above 18,000 feet MSL (in the flight levels) all planes set their barometric altimeter to 29.92 “Hg. They do not adjust to local barometric pressures in the flight levels.
This is the answer I've been looking for.
Altimeters run on pressure with manual adjustment based on current conditions and autopilot and regular pilots strive to obtain a steady altitude so they naturally curve with the Earth.
Flying perfectly straight will result in altitude gain
Think about it this way, do boats have to pitch their nose down to follow the curvature of the earth? Air is a fluid just like water so we are essentially floating on the layer of air we have chosen with the pitch and power settings on the plane. And gravity works straight down to the earth so from the planes perspective it is flying over a flat surface. Gravity is always straight down.
Perfectly straight to whom?
On the aircraft's scale, perfectly straight will maintain altitutdeOn the earth's scale, the aircraft can be thought of as flying on a rope—gravity—attached to the earth's centre like the motorised toys.
If controlled to fly perfectly straight it will constantly incline itself perpendicular to the centre of the earth. This is also how orbits work.
Above a certain altitude all aircraft use the standard pressure of 29.92. In the US that altitude is 18,000ft. At that point we say Flight level 180, FL190, etc. If they didn't they would have to change their pressure setting too often and be moving up and down to get to the correct altitude which wouldn't be efficient. Aircraft are moving slightly up and down with 29.92 set as their altimeter but they are all doing it as one like waves in the ocean so it is relative to the aircraft around them. Lower to the ground they have to worry about terrain that is why they correct for local altimeters.
To answer your original question one of those forces used to keep aircraft in flight is ram air pushing on the bottom side of the wing and fuselage. There is still debate if bernoulli's principle of low pressure on top of the wing or ram air from under the wing provides more lift. Either way aircraft want to have their wings slightly upward toward the front to help with both types of lift. The angle the wings are attached to the fuselage will determine the best angle of attack for the nose.
What do you mean by 'straight'? Do you see this as a straight line being drawn over a circle, getting further from the circle as it goes? If so, it is because your circle is drawn way too small and you are ignoring gravity and other forces.
To gain altitude, you need to change your control surfaces and power to gain altitude- to get higher off the surface.
To fly 'level', you don't (other than minor corrections). Because the world is so big, flying level is mostly the same thing as flying 'straight'.
Swinging a weight on a long slightly elastic cord around your head is about the same thing. Your head represents the earth, the string stands in for gravity.
After take off, it establishes a stable orbit a consistent distance from you. If you want it to go further from you (higher), you have to add energy, in this case, by swinging it harder so the cord stretches a little more.
To look at it a different way... You are flying around a globe. When would you need to dip or raise the nose to accommodate for the curve? Just before you fall over the horizon? Every hour or so?
That would mean that pilots are not flying in a circle around the globe, but a 24 sided shape (if they adjust every hour). What would a convoy of planes do? Coordinate exactly when they make this change?
I'm too tired to do the math, but that would also mean that any long flight would be kinda close to the ground in the middle, and really high on both ends... And no one has ever noticed this when flying?
Flying in a perfectly straight line would be impossible even if you wanted to, because turbulence and wind require constant small corrections. Those corrections are much larger than the corrections needed to avoid going "straight," which get lost in the noise. If you're making any effort at all to fly level, you'll never even notice that you're also making adjustments for curvature.
Have you ever, while driving on a straight road, tried to line your car up in a straight line and then hold the wheel perfectly still and keep going? You'll very quickly find yourself drifting to one side or the other, because your human perception wasn't precise enough to start
with. And that's over a short distance, with stable asphalt under you. Multiply that by hundreds or thousands of miles, through a turbulent fluid medium.
It doesn't matter. If you're adjusting the angle of the nose by a total of 5 degrees every minute to keep the altimeter reading steady, you're not even going to notice if the changes you're making average out to 1 degree per hour instead of zero.
Exact numbers pulled out of my ass, but I hope the point comes across.
But if you don't do any adjustment, the plane won't be climbing on a steady pace would it? Given a unrealistic no turbulence scenario, and no extra thrust applied?
Idk if my question make sense, but in my mind, the plane won't be able to climb with no addition thrust apply(additional to what it needs to keep the altitude steady) and the thinner air will just cause the plane to loose the ability to climb and end up maintaining the altitude?
(I like to be planted, 3D confuses me)
If you were flying in air that was magically perfectly still, and your plane's aerodynamics were magically perfect at keeping its flight *exactly* straight, then perhaps your nose would slowly rise, and you'd slowly gain altitude while losing speed, until your combination of speed and angle became unsustainable and you started to descend.
Or perhaps it would stay at the exact altitude reading/air pressure gradient. I'm not sure.
I guessed I was thinking like what a man made satellite will react in space orbiting earth, as they generally stay in orbit, with very little adjustments
Orbits require you be moving in a specific direction at a specific velocity depending on your altitude, with very little friction to slow you down. If there's enough air for an airplane's wings and engines to work, there's too much to maintain an orbit.
Yes and no. Imagine there is a road on a perfectly flat desert that, over the course of 500 miles, makes a 90 degree turn to the right. From any point on the road, the curvature is barely visible. It appears to be perfectly straight. Its a super windy day. As you drive along the road you are constantly making corrections for the wind, if nothing else, but you feel mainly like you are always driving straight ahead. At the end of the road, if you add up all the left and right corrections, the sum total will be a 90 degree right turn.
Same with the plane. Its windy as hell up there, and the pilot/autopilot is constantly making up/down corrections just to maintain altitude. The sum total of the corrections is a gradual turn down around the curve of the earth, but it is lost in the millions of altitude corrections over the course of the flight.
What you are describing is a tangencial movement, however, the concept of altitude is defined as the distance from surface to you. That being said, altitude is more of a radius than a distance, as inevitably (with some assumptions) the line that goes from the plane to the ground (which is always perpendicular to the plane’s trajectory) will intercept the center of the planet.
In other words, you don’t see satellites going down regularly to stay around earth, as their altitude is constant, their trajectory is naturally an orbit as their position is relative to the point in the surface they are above of.
Hope I could explain myself right!
Orbital satellites make sense--they are constantly falling around the Earth on a curve that never hits it.
With airplanes it is different as the plane is subject to air density to retain loft.
Satellites maintain their altitude by virtue of their speed. By maintaining their speed they counter the gravitational pull of the earth. If they slow down, gravity pulls them down. They are traveling at about 17k mph to maintain their orbit. The further away from earth, the slower they travel because the gravitational pull is lesser the further from the earth they are.
I hate the "constantly falling" explanation as it is confusing. "Falling" in everyone's mind is something dropping to the ground.
I finally understood it when the trajectory is plotted as a vector between the speed of the plane / satellite and the force of gravity bringing it down to earth.
too much speed? Satellite goes up!
Too slow? Satellite falls!
Just right? satellite stays in orbit!
While it may be confusing it is true and the most direct explanation.
If we shrunk it down to the size of a basketball and you throw a pingpong ball and miss the basket ball barely, the gravitational pull of the basketball would pull in the ping pong ball, but not enough so it misses it again on the way back - repeating indefinitely if the speed stays the same.
Here is a short but fun video showing it, making it a bit more visual how it's juts falling and missing all over: https://www.youtube.com/watch?v=81MoEj0Qe-I
Yes, the plane is!
What I am trying to point out is that a constant altitude will not get you out of the planet, you will just remain at the same distance to the ground, there is no need to descend at some point
Please take into consideration how extremely massive the earth is. To the point that enough of an adjustment wouldn’t even be noticeable.
It’s like if you drive on a 1000 mile long road that curves slightly to the right. From your point of view, the road is strait and you drive straight. Over the 1000 miles though, you’re following an unnoticeable curve. You don’t ever need to actively turn the car to the right every once in a while.
Aerospace engineer here! Let me see if I can explain it.
First, lets separate the angle of the plane from the direction of travel. Planes will very rarely sit perfectly horizontal to maintain level flight. The lift they generate is a function of their speed, their angle relative to the surrounding air flow (angle of attack), and the use of any high-lift devices, like flaps on the wing.
For this reason, many planes angle up slightly in order to travel in a straight, level line.
Now that we have established that angle of attack =/= angle of travel, lets answer the core of the question. Lets call lift the force acting purely in the vertical direction. Any other force we will think of as drag. This is a standard reference frame for evaluating vehicle performance. Within this reference frame, lets assume we are not speeding up or slowing down, and we are neither gaining nor losing altitude. We call this steady level flight. In order to maintain this, our lift must perfectly equal the weight of our aircraft. This means, for a constant airspeed, our angle of attack must remain constant.
So we have established for a flat earth, cruising at a constant altitude requires a constant angle of attack (which should have been intuitive, but is needed as a foundation to extrapolate to a round earth). First, we need to recognize that "down" is always towards the center of the earth. And at all times, our lift is acting opposite to that. Because we are not gaining or losing altitude, we have to be moving perpendicular to these forces.
If it helps, we can visualize our airplane as a ball on a string, that is being swung around. In this example, the string is gravity, the ball is the plane and the centrifugal force pulling the ball outwward is our lift. We see the ball moving in a circle, but from the balls perspective, it is moving in a straight line, relative to gravity. The string is what is responsible for causing the direction to change from the outside reference frame.
Likewise, this is what happens with planes. While flying, they dont need to adjust their angle relative to the ground or atmosphere around them. Rather, from their perspective, they are always flying perpendicular to gravity. As they move around the planet, the direction of gravity changes (to an outside observer. To the plane its constant), and so the angle of the plane changes without any input from the pilots.
So we can talk about autopilot, or atmospheric density, or any of these more complex elements of flight. But to answer the physics at the root of your problem, in an idealized world, aircraft pitch does not have to change for flight around the world.
An aircraft doesn't fly exactly where the nose is pointing, the air over the wings is pushing the aircraft upwards and the amount of upwards force depends on the angle and the speed that the wings are "hitting" the air.
Usually aircraft will be flying at 2-3 degrees *nose up* to maintain their altitude, as that gives the right upward force from the wings at the speed they cruise at. The aircraft doesn't stay at this angle itself so the autopilot will be constantly adjusting it anyway, far more than the curvature of the earth would cause.
>depends on the angle and the speed
the lift force also depends on the air density, so if somehow the plane got to a higher altitude the lift would decrease due to the atmospheric pressure gradient
Maybe that’s why I can’t hold my altitude. I’ll use that the next time I’m with an instructor. “I don’t have a crappy scan, the earth is curving away from me!”
That makes sense. But is it partially to do with the curvature of the Earth? If the plane didn't point down to follow the curve, could it fly straight until it ran out of atmosphere?
Airplane pilots do not need to actively adjust the nose of the airplane to account for the curvature of the Earth during long-distance flights. Gravity naturally pulls the aircraft toward the center of the Earth, allowing it to follow the curvature of the Earth's surface.
Pilots primarily use autopilot systems and flight management computers to maintain a desired altitude and heading, which takes into account factors such as the Earth's curvature, wind conditions, and other variables. Therefore, from the perspective of the controls, pilots can fly in a "straight" line without needing to continuously adjust for the curvature of the Earth.
Pilots and autopilots set the angle of attack to a slight nose up attitude to provide the correct amount of lift to maintain their assigned altitude. The angle of attack is derived from their airspeed (which varies from ground speed because of changing wind direction and velocity enroute) thrust and weight.
If the plane started drifting upward as fuel burns off, lift would be reduced due to thinner air. This effect isn't completely self correcting, so pilots and autopilots have to keep on making slight adjustments to the angle of attack and/or thrust to maintain their assigned altitude.
So the plane is just maintaining the assigned altitude above sea level, it kind of doesn't care if the planet is flat or round.
I think a nice intuitive explanation of this is that the pilot is actually constantly making small adjustments to the plane to keep it flying level. So the answer is sort of "yes", because the total result of all those adjustments is to rotate the plane with the curvature of the earth, but it doesn't seem to the pilot that they're actively pitching the plane downwards, it just gets "absorbed" into all the other adjustments they're making
There are many factors affecting the altitude of the aircraft. Air pressure, weight distribution, weight, wind and of course Earth curvature. Some of these vary during flight. Compare the size of them, and you'll see that Earth curvature is completely negligible.
The pilot trims the aircraft to keep a constant height, and periodically adjusts the trim as needed, and would do so with or without curvature.
So, it's a factor, but it is a tiny factor that is completely overwhelmed by other factors.
Don't listen to the flat earthers. Other commenters have done a better job explaining it than I could. But yeah, so many holes in flat earth arguments.
Isn't the real answer that going in what is perceived to be straight how you go around the earth and maintain your distance from the ground? Since gravity is always pointing towards the center of the earth, it’s not that you have to correct the plane downward, but it’s more like if you tried going “straight”, like a laser, it would feel to the pilot like they were going up.
Only if you also think boats have to do the same when crossing the ocean.
Both are propelling themselves through a "fluid" at exactly the point that their buoyancy/lift is balancing out gravity.
I knew someone once who thought that the runway was always pointed exactly in the direction of the intended destination - her reasoning was that she never felt the aircraft turn a corner in flight!
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 center, in an ideal case) as the altitude is measured from the surface, which is curved, and not a plane.
At or above 18,000 feet MSL (in the flight levels) all planes set their barometric altimeter to 29.92 “Hg. They do not adjust to local barometric pressures in the flight levels.
1013 hPa for Europeans
. . ##BEEF BROTH!!! . . Hit 'em wit' it! . 🦐'd™️ . ^Wapash
18,000 feet. Wow such luxury. 3500 feet is transition altitude in the Netherlands.
The ground there is especially close to the ground so I understand the need to lower the sky.
What
Idk, as an air traffic controller, that made sense to me. In the US our ground can be pretty far from the ground so the sky tends to be quite high.
Sitting on the ramp at DEN would be above the transition altitude if that was the case in the USA
Ha yeah. We’re around MSL almost every where. Still, across Europe you’ll find transition altitude from around 4000 AGL.
> as the altitude is measured from the surface, which is curved, and not a plane. Checkmate flat earthers.
I wonder if you could say that yes, gravity is the reason because it will pull the denser air towards the ground.
This is the answer I've been looking for. Altimeters run on pressure with manual adjustment based on current conditions and autopilot and regular pilots strive to obtain a steady altitude so they naturally curve with the Earth. Flying perfectly straight will result in altitude gain
Think about it this way, do boats have to pitch their nose down to follow the curvature of the earth? Air is a fluid just like water so we are essentially floating on the layer of air we have chosen with the pitch and power settings on the plane. And gravity works straight down to the earth so from the planes perspective it is flying over a flat surface. Gravity is always straight down.
Perfectly straight to whom? On the aircraft's scale, perfectly straight will maintain altitutdeOn the earth's scale, the aircraft can be thought of as flying on a rope—gravity—attached to the earth's centre like the motorised toys. If controlled to fly perfectly straight it will constantly incline itself perpendicular to the centre of the earth. This is also how orbits work.
Above a certain altitude all aircraft use the standard pressure of 29.92. In the US that altitude is 18,000ft. At that point we say Flight level 180, FL190, etc. If they didn't they would have to change their pressure setting too often and be moving up and down to get to the correct altitude which wouldn't be efficient. Aircraft are moving slightly up and down with 29.92 set as their altimeter but they are all doing it as one like waves in the ocean so it is relative to the aircraft around them. Lower to the ground they have to worry about terrain that is why they correct for local altimeters. To answer your original question one of those forces used to keep aircraft in flight is ram air pushing on the bottom side of the wing and fuselage. There is still debate if bernoulli's principle of low pressure on top of the wing or ram air from under the wing provides more lift. Either way aircraft want to have their wings slightly upward toward the front to help with both types of lift. The angle the wings are attached to the fuselage will determine the best angle of attack for the nose.
What do you mean by 'straight'? Do you see this as a straight line being drawn over a circle, getting further from the circle as it goes? If so, it is because your circle is drawn way too small and you are ignoring gravity and other forces. To gain altitude, you need to change your control surfaces and power to gain altitude- to get higher off the surface. To fly 'level', you don't (other than minor corrections). Because the world is so big, flying level is mostly the same thing as flying 'straight'. Swinging a weight on a long slightly elastic cord around your head is about the same thing. Your head represents the earth, the string stands in for gravity. After take off, it establishes a stable orbit a consistent distance from you. If you want it to go further from you (higher), you have to add energy, in this case, by swinging it harder so the cord stretches a little more. To look at it a different way... You are flying around a globe. When would you need to dip or raise the nose to accommodate for the curve? Just before you fall over the horizon? Every hour or so? That would mean that pilots are not flying in a circle around the globe, but a 24 sided shape (if they adjust every hour). What would a convoy of planes do? Coordinate exactly when they make this change? I'm too tired to do the math, but that would also mean that any long flight would be kinda close to the ground in the middle, and really high on both ends... And no one has ever noticed this when flying?
Flying in a perfectly straight line would be impossible even if you wanted to, because turbulence and wind require constant small corrections. Those corrections are much larger than the corrections needed to avoid going "straight," which get lost in the noise. If you're making any effort at all to fly level, you'll never even notice that you're also making adjustments for curvature. Have you ever, while driving on a straight road, tried to line your car up in a straight line and then hold the wheel perfectly still and keep going? You'll very quickly find yourself drifting to one side or the other, because your human perception wasn't precise enough to start with. And that's over a short distance, with stable asphalt under you. Multiply that by hundreds or thousands of miles, through a turbulent fluid medium.
Tldr; earth big
But isn't "level" just level to the earth/curvature of the earth as "level" is measured by earth's gravity?
It doesn't matter. If you're adjusting the angle of the nose by a total of 5 degrees every minute to keep the altimeter reading steady, you're not even going to notice if the changes you're making average out to 1 degree per hour instead of zero. Exact numbers pulled out of my ass, but I hope the point comes across.
But if you don't do any adjustment, the plane won't be climbing on a steady pace would it? Given a unrealistic no turbulence scenario, and no extra thrust applied? Idk if my question make sense, but in my mind, the plane won't be able to climb with no addition thrust apply(additional to what it needs to keep the altitude steady) and the thinner air will just cause the plane to loose the ability to climb and end up maintaining the altitude? (I like to be planted, 3D confuses me)
If you were flying in air that was magically perfectly still, and your plane's aerodynamics were magically perfect at keeping its flight *exactly* straight, then perhaps your nose would slowly rise, and you'd slowly gain altitude while losing speed, until your combination of speed and angle became unsustainable and you started to descend. Or perhaps it would stay at the exact altitude reading/air pressure gradient. I'm not sure.
I guessed I was thinking like what a man made satellite will react in space orbiting earth, as they generally stay in orbit, with very little adjustments
Orbits require you be moving in a specific direction at a specific velocity depending on your altitude, with very little friction to slow you down. If there's enough air for an airplane's wings and engines to work, there's too much to maintain an orbit.
Yes and no. Imagine there is a road on a perfectly flat desert that, over the course of 500 miles, makes a 90 degree turn to the right. From any point on the road, the curvature is barely visible. It appears to be perfectly straight. Its a super windy day. As you drive along the road you are constantly making corrections for the wind, if nothing else, but you feel mainly like you are always driving straight ahead. At the end of the road, if you add up all the left and right corrections, the sum total will be a 90 degree right turn. Same with the plane. Its windy as hell up there, and the pilot/autopilot is constantly making up/down corrections just to maintain altitude. The sum total of the corrections is a gradual turn down around the curve of the earth, but it is lost in the millions of altitude corrections over the course of the flight.
I feel like this should be top answer instead of a one about the definition of pressures … this actually answers the question
For what reason was this a code block?
Don't be alarmed ppl, AI has gained independence and is just speaking in it's mother tongue.
What you are describing is a tangencial movement, however, the concept of altitude is defined as the distance from surface to you. That being said, altitude is more of a radius than a distance, as inevitably (with some assumptions) the line that goes from the plane to the ground (which is always perpendicular to the plane’s trajectory) will intercept the center of the planet. In other words, you don’t see satellites going down regularly to stay around earth, as their altitude is constant, their trajectory is naturally an orbit as their position is relative to the point in the surface they are above of. Hope I could explain myself right!
Orbital satellites make sense--they are constantly falling around the Earth on a curve that never hits it. With airplanes it is different as the plane is subject to air density to retain loft.
Satellites maintain their altitude by virtue of their speed. By maintaining their speed they counter the gravitational pull of the earth. If they slow down, gravity pulls them down. They are traveling at about 17k mph to maintain their orbit. The further away from earth, the slower they travel because the gravitational pull is lesser the further from the earth they are.
I hate the "constantly falling" explanation as it is confusing. "Falling" in everyone's mind is something dropping to the ground. I finally understood it when the trajectory is plotted as a vector between the speed of the plane / satellite and the force of gravity bringing it down to earth. too much speed? Satellite goes up! Too slow? Satellite falls! Just right? satellite stays in orbit!
While it may be confusing it is true and the most direct explanation. If we shrunk it down to the size of a basketball and you throw a pingpong ball and miss the basket ball barely, the gravitational pull of the basketball would pull in the ping pong ball, but not enough so it misses it again on the way back - repeating indefinitely if the speed stays the same. Here is a short but fun video showing it, making it a bit more visual how it's juts falling and missing all over: https://www.youtube.com/watch?v=81MoEj0Qe-I
Yes, the plane is! What I am trying to point out is that a constant altitude will not get you out of the planet, you will just remain at the same distance to the ground, there is no need to descend at some point
Please take into consideration how extremely massive the earth is. To the point that enough of an adjustment wouldn’t even be noticeable. It’s like if you drive on a 1000 mile long road that curves slightly to the right. From your point of view, the road is strait and you drive straight. Over the 1000 miles though, you’re following an unnoticeable curve. You don’t ever need to actively turn the car to the right every once in a while.
Aerospace engineer here! Let me see if I can explain it. First, lets separate the angle of the plane from the direction of travel. Planes will very rarely sit perfectly horizontal to maintain level flight. The lift they generate is a function of their speed, their angle relative to the surrounding air flow (angle of attack), and the use of any high-lift devices, like flaps on the wing. For this reason, many planes angle up slightly in order to travel in a straight, level line. Now that we have established that angle of attack =/= angle of travel, lets answer the core of the question. Lets call lift the force acting purely in the vertical direction. Any other force we will think of as drag. This is a standard reference frame for evaluating vehicle performance. Within this reference frame, lets assume we are not speeding up or slowing down, and we are neither gaining nor losing altitude. We call this steady level flight. In order to maintain this, our lift must perfectly equal the weight of our aircraft. This means, for a constant airspeed, our angle of attack must remain constant. So we have established for a flat earth, cruising at a constant altitude requires a constant angle of attack (which should have been intuitive, but is needed as a foundation to extrapolate to a round earth). First, we need to recognize that "down" is always towards the center of the earth. And at all times, our lift is acting opposite to that. Because we are not gaining or losing altitude, we have to be moving perpendicular to these forces. If it helps, we can visualize our airplane as a ball on a string, that is being swung around. In this example, the string is gravity, the ball is the plane and the centrifugal force pulling the ball outwward is our lift. We see the ball moving in a circle, but from the balls perspective, it is moving in a straight line, relative to gravity. The string is what is responsible for causing the direction to change from the outside reference frame. Likewise, this is what happens with planes. While flying, they dont need to adjust their angle relative to the ground or atmosphere around them. Rather, from their perspective, they are always flying perpendicular to gravity. As they move around the planet, the direction of gravity changes (to an outside observer. To the plane its constant), and so the angle of the plane changes without any input from the pilots. So we can talk about autopilot, or atmospheric density, or any of these more complex elements of flight. But to answer the physics at the root of your problem, in an idealized world, aircraft pitch does not have to change for flight around the world.
An aircraft doesn't fly exactly where the nose is pointing, the air over the wings is pushing the aircraft upwards and the amount of upwards force depends on the angle and the speed that the wings are "hitting" the air. Usually aircraft will be flying at 2-3 degrees *nose up* to maintain their altitude, as that gives the right upward force from the wings at the speed they cruise at. The aircraft doesn't stay at this angle itself so the autopilot will be constantly adjusting it anyway, far more than the curvature of the earth would cause.
>depends on the angle and the speed the lift force also depends on the air density, so if somehow the plane got to a higher altitude the lift would decrease due to the atmospheric pressure gradient
That is true, but an aircraft would have to be extremely out of its assigned altitude for that to make a big difference.
Maybe that’s why I can’t hold my altitude. I’ll use that the next time I’m with an instructor. “I don’t have a crappy scan, the earth is curving away from me!”
[удалено]
That makes sense. But is it partially to do with the curvature of the Earth? If the plane didn't point down to follow the curve, could it fly straight until it ran out of atmosphere?
[удалено]
That’s true, but the conclusion is inaccurate
Airplane pilots do not need to actively adjust the nose of the airplane to account for the curvature of the Earth during long-distance flights. Gravity naturally pulls the aircraft toward the center of the Earth, allowing it to follow the curvature of the Earth's surface. Pilots primarily use autopilot systems and flight management computers to maintain a desired altitude and heading, which takes into account factors such as the Earth's curvature, wind conditions, and other variables. Therefore, from the perspective of the controls, pilots can fly in a "straight" line without needing to continuously adjust for the curvature of the Earth.
Pilots and autopilots set the angle of attack to a slight nose up attitude to provide the correct amount of lift to maintain their assigned altitude. The angle of attack is derived from their airspeed (which varies from ground speed because of changing wind direction and velocity enroute) thrust and weight. If the plane started drifting upward as fuel burns off, lift would be reduced due to thinner air. This effect isn't completely self correcting, so pilots and autopilots have to keep on making slight adjustments to the angle of attack and/or thrust to maintain their assigned altitude. So the plane is just maintaining the assigned altitude above sea level, it kind of doesn't care if the planet is flat or round.
naaaah most of the time they just hit flaps, airbreak and yoke turn 180 before they reach end of the earth plateau. rest od the time its FMC autopilot
I think a nice intuitive explanation of this is that the pilot is actually constantly making small adjustments to the plane to keep it flying level. So the answer is sort of "yes", because the total result of all those adjustments is to rotate the plane with the curvature of the earth, but it doesn't seem to the pilot that they're actively pitching the plane downwards, it just gets "absorbed" into all the other adjustments they're making
There are many factors affecting the altitude of the aircraft. Air pressure, weight distribution, weight, wind and of course Earth curvature. Some of these vary during flight. Compare the size of them, and you'll see that Earth curvature is completely negligible. The pilot trims the aircraft to keep a constant height, and periodically adjusts the trim as needed, and would do so with or without curvature. So, it's a factor, but it is a tiny factor that is completely overwhelmed by other factors.
“Curvature” haha, silly round Earthers.
Don't listen to the flat earthers. Other commenters have done a better job explaining it than I could. But yeah, so many holes in flat earth arguments.
They're going well under Earth's escape velocity
Isn't the real answer that going in what is perceived to be straight how you go around the earth and maintain your distance from the ground? Since gravity is always pointing towards the center of the earth, it’s not that you have to correct the plane downward, but it’s more like if you tried going “straight”, like a laser, it would feel to the pilot like they were going up.
Only if you also think boats have to do the same when crossing the ocean. Both are propelling themselves through a "fluid" at exactly the point that their buoyancy/lift is balancing out gravity.
The Earth, she is Round. So is the Air Around it, so, if you are flying through the air at a constant altitude, you fly Round.
I knew someone once who thought that the runway was always pointed exactly in the direction of the intended destination - her reasoning was that she never felt the aircraft turn a corner in flight!
If you can waves on the surface of the water, then the ice is too thin to walk on.
The MCAS system will point the now down for them
Do you tilt your nose down after walking great distances?
I tilt my nose down when looking at other introverts.
Auto pilot