Long flight altitude?

Status
Not open for further replies.
W

Wleaks

Ejection Handle Pulled
Joined
Oct 27, 2015
Messages
10
Display Name
Display name:
W leaks
Hi everyone I had a quick question on flights for long periods . If someone has asked it please forgive me and I'm sorry if it sounds stupid but...
Question is when you take off and hit cruising altitude what adjustments need to be made to stay at that altitude as far as wind, gravity earth curvature etc?

Meaning if you are at say 10,000 feet and gravity is pulling you down or wind and in these long flights how often do you have to dip the nose to stay at the 10,000..does throttling keep you at 10,000 until decent?

They say there's no such thing as a stupid question but I might have something to share in that compartment ;)
Thanks
 
Get your cruise altitude and power setting, trim, lean mixture as appropriate, adjust power/retrim.

Repeat as necessary. It can be a constant fiddling act depending on conditions.
 
If you have altitude hold on your autopilot you may have to adjust because of changes is barometric pressure.
 
Curvature of the earth is not pertinent. Gravity is. It is always perpendicular to the earth. Ya just have to create the exact amount of lift it takes to balance out the gravity. That's done with power adjustments and elevator adjustments. Those adjustments sometimes just need to be made every now and then and sometimes almost constantly if the air is unstable
 
Trim and keep an eye on the power if it changes re trim.
 
Wleaks said:
Hi everyone I had a quick question on flights for long periods . If someone has asked it please forgive me and I'm sorry if it sounds stupid but...
Question is when you take off and hit cruising altitude what adjustments need to be made to stay at that altitude as far as wind, gravity earth curvature etc?

Meaning if you are at say 10,000 feet and gravity is pulling you down or wind and in these long flights how often do you have to dip the nose to stay at the 10,000..does throttling keep you at 10,000 until decent?

They say there's no such thing as a stupid question but I might have something to share in that compartment ;)
Thanks
Click to expand...




Depends on if it's a leap year and global warming.
 
Wleaks said:
Hi everyone I had a quick question on flights for long periods . If someone has asked it please forgive me and I'm sorry if it sounds stupid but...
Question is when you take off and hit cruising altitude what adjustments need to be made to stay at that altitude as far as wind, gravity earth curvature etc?

Meaning if you are at say 10,000 feet and gravity is pulling you down or wind and in these long flights how often do you have to dip the nose to stay at the 10,000..does throttling keep you at 10,000 until decent?

They say there's no such thing as a stupid question but I might have something to share in that compartment ;)
Thanks
Click to expand...
If you are not traveling close to orbital or escape velocity, lift will counteract the pull of gravity and you'll stay at 10000 ft, assuming the aircraft is "trimmed" or controlled for constant speed and attitude (not pointing up or down.)
 
Now there is one aspect of flight where the curvature of the earth is significant (coupled with the earth's rotation)...
 
I find myself adjust throttle more often than trim
 
The answer, of course, is gravity. The airplane is trimmed to fly at a particular air density. An altimeter is a pressure gauge calibrated in feet (or meters). Since the air layer (all other complicating factors like wind, temperature, moisture content, etc. ignored) stays at a constant density at a constant distance from the gravity source, the plane will follow the curvature of the earth.

John
 
Thanks for all the replys, so im assuming keeping it trimmed is the key to level flight, this makes me wonder though?
So let's say I'm only making the minor adjustments and "following the curvature of the earth" wouldn't I hypothetically at some point turn upside down? Say under the globe going to china?..I know it sounds silly but what do you do in to combat this situation as far as turning upside down in long flight around the globe? :dunno: thanks again
 
Wleaks said:
Thanks for all the replys, so im assuming keeping it trimmed is the key to level flight, this makes me wonder though?
So let's say I'm only making the minor adjustments and "following the curvature of the earth" wouldn't I hypothetically at some point turn upside down? Say under the globe going to china?..I know it sounds silly but what do you do in to combat this situation as far as turning upside down in long flight around the globe? :dunno: thanks again
Click to expand...

The best way to do it is to point your aircraft opposite the direction of the earth's rotation, that way you will hover in one spot and you will always be on top.

Failing the ability to do that, as long as you can keep within the Earth's influence of gravity and still maintain positive G's in level flight, I think you're good to go.
 
Wleaks said:
Thanks for all the replys, so im assuming keeping it trimmed is the key to level flight, this makes me wonder though?
So let's say I'm only making the minor adjustments and "following the curvature of the earth" wouldn't I hypothetically at some point turn upside down? Say under the globe going to china?..I know it sounds silly but what do you do in to combat this situation as far as turning upside down in long flight around the globe? :dunno: thanks again
Click to expand...
It's a difficult problem. I just moved back to the US after a couple of years in australia. It's been a real joy to wear regular shoes again instead of the claw-equipped australian shoes that were needed to prevent one from falling into space. On the plus side the airplane i was flying down there had incredible short field performance, just release the brakes and it falls into the air.
 
Wleaks said:
Thanks for all the replys, so im assuming keeping it trimmed is the key to level flight, this makes me wonder though?
So let's say I'm only making the minor adjustments and "following the curvature of the earth" wouldn't I hypothetically at some point turn upside down? Say under the globe going to china?..I know it sounds silly but what do you do in to combat this situation as far as turning upside down in long flight around the globe? :dunno: thanks again
Click to expand...

Maybe you need to ask the people in Australia how they stay stuck to the Earth and don't just fall out into Space toward Uranus. I've often wondered that myself. :mad2: :rolleyes2:
 
Gotta watch out for the edge of the world, fly too far off it and you're in space. That's no good, navigation would be really hard.
 
Until post #13, I thought this thread was real...

What a shame that some people have nothing better to do with their time...
 
First of all why would a "troll" ask somthing as important as this? How long have you been flying , especially if you fly comercial and never could answer the question of flight and earth curvature? ..I'm seriously asking a question?..and sense you seem to be so smart how about an answer. .how does the plane not turn upside down going around the earth?..thanks again for any intelligent answers ;)
 
I guess that's your attempt at an intelligent answer. .I hope you take flight more serious...o I'm to assume that all your years of flight and you can't answer a simple question of how aerodynamics in flight work?..come on is there any real pilots on this board?
 
Im sorry i didn't notice your rig was a Arrow 600 E-LSA I thought I was talking to a real pilot that could fly faster than 100 kts? At 1 mile per hour you probably wouldn't have to deal with earth curvature and with the seating capacity a good woman wouldn't have to deal with you attempts at intelligence or what you think is comedy :)
 
Wleaks said:
Im sorry i didn't notice your rig was a Arrow 600 E-LSA I thought I was talking to a real pilot that could fly faster than 100 kts? At 1 mile per hour you probably wouldn't have to deal with earth curvature and with the seating capacity a good woman wouldn't have to deal with you attempts at intelligence or what you think is comedy :)
Click to expand...

Reported.

I hope you enjoy your (hopefully short) stay.
 
That's what I was thinking about trim and hight but the Earth is 25,000 miles in circumference curveting 8 inches per mile squared, a pilot wishing to simply maintain their altitude at a typical cruising speed of 500 mph, would have to constantly dip their nose downwards and descend 2,777 feet (over half a mile) every minute! Otherwise, without compensation, in one hour’s time the pilot would find themselves 166,666 feet (31.5 miles) higher than expected!

A plane flying at a typical 35,000 feet wishing to maintain that altitude at the upper-rim of the so-called “Troposphere” in one hour would find themselves over 200,000 feet high into the “Mesosphere” with a steadily raising trajectory the longer they go. I have talked to several pilots, and no such compensation for the Earth’s supposed curvature is ever made. When pilots set an altitude, their artificial horizon gauge remains level and so does their course; nothing like the necessary 2,777 foot per minute declination is ever taken into consideration.

To maintain a 30,000 ft. altitude around a round Earth, the airplane would have to be angled significantly lower than in the rear of the airplane to maintain a 30,000 foot relationship to the Earth’s curvature.

Yet this never, ever happens. When traveling in an airplane it is level form nose to stern.

These aren't figures they are facts of how much curvature to expect in flight yet no pilot can refute them or give me answer that works in real world..flight simulators are on a flat plane and real world flight takes place on a ball? How can this be? Can anyone give me a real world answer?
Otherwise we will have to conclude the earth is not a globe but a level plane we fly above hence the name "aero-plane"
 
FastEddieB said:
It does.

Especially a problem if the pilot is female.



Happy to help.
Click to expand...
So just for the record pilots of America would ban me for asking questions about fight around the world but not derogatory insults to women? .. hmm I wonder
 
Wleaks said:
That's what I was thinking about trim and hight but the Earth is 25,000 miles in circumference curveting 8 inches per mile squared, a pilot wishing to simply maintain their altitude at a typical cruising speed of 500 mph, would have to constantly dip their nose downwards and descend 2,777 feet (over half a mile) every minute! Otherwise, without compensation, in one hour’s time the pilot would find themselves 166,666 feet (31.5 miles) higher than expected!

A plane flying at a typical 35,000 feet wishing to maintain that altitude at the upper-rim of the so-called “Troposphere” in one hour would find themselves over 200,000 feet high into the “Mesosphere” with a steadily raising trajectory the longer they go. I have talked to several pilots, and no such compensation for the Earth’s supposed curvature is ever made. When pilots set an altitude, their artificial horizon gauge remains level and so does their course; nothing like the necessary 2,777 foot per minute declination is ever taken into consideration.

To maintain a 30,000 ft. altitude around a round Earth, the airplane would have to be angled significantly lower than in the rear of the airplane to maintain a 30,000 foot relationship to the Earth’s curvature.

Yet this never, ever happens. When traveling in an airplane it is level form nose to stern.

These aren't figures they are facts of how much curvature to expect in flight yet no pilot can refute them or give me answer that works in real world..flight simulators are on a flat plane and real world flight takes place on a ball? How can this be? Can anyone give me a real world answer?
Otherwise we will have to conclude the earth is not a globe but a level plane we fly above hence the name "aero-plane"
Click to expand...

Because when you set an autopilot to an altitude, or you set your trim to an airspeed for level flight both are based on the density of the air at your current altitude. The plane wants to stay at that air density. That air density curves around the earth (local variations notwithstanding) so the airplane rides around in an arc "parallel" to the earth's surface, not a horizontal line.
 
The real answer lies in the problem of the curvature of the earth. Without adjusting for pi * Velocity over time, you will in fact have a straight line flight path. The problem with this is that eventually you will simply fly straight off the earth. Imagine the earth as a basketball. Now balance a yardstick on the ball to represent your unadjusted flight path, and you will immediately see the problem.

Fortunately, and in answer to your question, modern aircraft all have equipment to adjust for this automatically so there's no need to give it a thought during flight. If you look out under your wing you will see a small tube pointing forward. This is known as the PITOT (PI Transit over time), what we refer to as the pitot tube. The hole at the end of the pitot tube is sized so that air that gets rammed into it at a constant flow equal to PI at any given speed, which turns a turbine in the altimeter to automatically adjust you flight path to equal the curvature of the earth.

An interesting historical note: During the first US manned mission into space, you can hear Alan Shepard in the audio recordings nervously talking over the transmissions of Houston Control. Control was desperately trying to get Shepard to shut the PITOT so that his craft would stop compensating for curvature and start its ascent into space. The radio operator ended up shouting right as Shepard took a breath for air, "Shut your PI hole!" The double meaning of this was evident, and that's where we get the term "Shut your pie hole."

Anyway, end of history lesson.
 
Last edited:
Stingray Don said:
Perhaps refer to your previous troll attempt for your answers.

http://www.pilotsofamerica.com/forum/showthread.php?t=81535&highlight=curvature+earth
Click to expand...
I've never been to this website. .although it looks like an interesting read ..I will check it out..the question was a ked before based on the fact that it's a valid question. .for instance take a toy aroplane and put it over a basketball and then make it go around the ball without it turning upside down..now do you get it?. The question is valid and can't be answered by science so I turned to pilots in the hope maybe you could answer it?
 
Wleaks said:
I've never been to this website. .although it looks like an interesting read ..I will check it out..the question was a ked before based on the fact that it's a valid question. .for instance take a toy aroplane and put it over a basketball and then make it go around the ball without it turning upside down..now do you get it?. The question is valid and can't be answered by science so I turned to pilots in the hope maybe you could answer it?
Click to expand...

Bad example. The basketball doesn't have its own atmosphere, nor enough gravity to influence the toy plane.
 
EdFred said:
Bad example. The basketball doesn't have its own atmosphere, nor enough gravity to influence the toy plane.
Click to expand...

So according to gravity and the above posts if you set your cruising altitude you would never have to adjust for mountains because magic gravity would do it for you and keep you level on the plane. .this is nonsensical and still gravity is the "theory that one object attracts another not how the plane dosnt turn upside down under the ball.
 
Wleaks said:
So according to gravity and the above posts if you set your cruising altitude you would never have to adjust for mountains because magic gravity would do it for you and keep you level on the plane. .this is nonsensical and still gravity is the "theory that one object attracts another not how the plane dosnt turn upside down under the ball.
Click to expand...

No, because the density at an altitude is based on sea level, not ground level. The air pressure at 25,000ft over the Rockies is the same as over the Gulf of Mexico for all intents and purposes. So when you set for 25,000 ft that altitude wraps around the earth. It does not extend in horizontal lines. The only time you have to adjust for mountains is if your altitude is lower than the tops of them. Planes have a difficult time flying through rocks.

atmosphere_sm.jpg


See how all those layers curve, and aren't straight lines? Inside each of those layers are more layers. The plane wants to stay in the layer it is trimmed for, or the altitude it is set for. So it stays at a distance constantly equal relative to Mean Sea Level.
 
Last edited:
Wleaks said:
To maintain a 30,000 ft. altitude around a round Earth, the airplane would have to be angled significantly lower than in the rear of the airplane to maintain a 30,000 foot relationship to the Earth’s curvature.

Yet this never, ever happens. When traveling in an airplane it is level form nose to stern.
Click to expand...

Do you really know this for a fact? The fact that you can set a wine glass on your meal tray without it sliding forward is an artifact of the business class "auto leveling system" which keeps the floor of the interior level while the nose of the plane is pointing thirty degrees down bubble.

How else would you expect the FA's to be able to walk?

(Pro tip: Take Cathay Pacific on trans-equatorial flights. Their FA's look damned fine in their skirts, and even more so when you invert them.)
 
EdFred said:
No, because the density at an altitude is based on sea level, not ground level. The air pressure at 25,000ft over the Rockies is the same as over the Gulf of Mexico for all intents and purposes. So when you set for 25,000 ft that altitude wraps around the earth. It does not extend in horizontal lines. The only time you have to adjust for mountains is if your altitude is lower than the tops of them. Planes have a difficult time flying through rocks.

atmosphere_sm.jpg


See how all those layers curve, and aren't straight lines? Inside each of those layers are more layers. The plane wants to stay in the layer it is trimmed for, or the altitude it is set for. So it stays at a distance constantly equal relative to Mean Sea Level.
Click to expand...
This doesn't explain what keeps the plane from being upside down when it's on the bottom of the Earth.

In an effort to keep my explanation easy for everyone to understand, I neglected to mention the other effect of the pitot tube and how we are able to effortlessly fly on the bottom of the earth without taking on unusual attitudes.

It's quite simple actually, and is another hidden function of the "magical" pitot tube. The engineers designing aircraft take each planes aerodynamics into account when determining the placement of the pitot tube. Without getting too complicated, it's placed just forward of the center of balance in order that the drag of the air into the opening creates a downward pressure on the nose, constantly pulling it down in equal relation to the curvature of the earth, so that the bottom of the plane in level flight is always oriented toward Earth.

I hope I'm not losing any of you with technical details. If you need me to expand on any details, just let me know.
 
QuiQuog said:
This doesn't explain what keeps the plane from being upside down when it's on the bottom of the Earth.

In an effort to keep my explanation easy for everyone to understand, I neglected to mention the other effect of the pitot tube and how we are able to effortlessly fly on the bottom of the earth without taking on unusual attitudes.

It's quite simple actually, and is another hidden function of the "magical" pitot tube. The engineers designing aircraft take each planes aerodynamics into account when determining the placement of the pitot tube. Without getting too complicated, it's placed just forward of the center of balance in order that the drag of the air into the opening creates a downward pressure on the nose, constantly pulling it down in equal relation to the curvature of the earth, so that the bottom of the plane in level flight is always oriented toward Earth.

I hope I'm not losing any of you with technical details. If you need me to expand on any details, just let me know.
Click to expand...

Without the math it's just a buncha words dontchaknow?
 
QuiQuog said:
This doesn't explain what keeps the plane from being upside down when it's on the bottom of the Earth.

In an effort to keep my explanation easy for everyone to understand, I neglected to mention the other effect of the pitot tube and how we are able to effortlessly fly on the bottom of the earth without taking on unusual attitudes.

It's quite simple actually, and is another hidden function of the "magical" pitot tube. The engineers designing aircraft take each planes aerodynamics into account when determining the placement of the pitot tube. Without getting too complicated, it's placed just forward of the center of balance in order that the drag of the air into the opening creates a downward pressure on the nose, constantly pulling it down in equal relation to the curvature of the earth, so that the bottom of the plane in level flight is always oriented toward Earth.

I hope I'm not losing any of you with technical details. If you need me to expand on any details, just let me know.
Click to expand...

The other problem is that it only shows what's going on in the top half. I think we can expect the heavier layers to settle down lowest, so in the Southern hemisphere the layers would be reversed.
 
The question is flawed. The top of the earth is only the top because we in the northern hemisphere print our maps that way. If W Leaks isn't a troll he's just confused by the limitations of printing a map.
 
Status
Not open for further replies.
Back
Top