My gyroscope says the world is Flat

Its wont always be a straight line for all routes. That would be impossible. But they make the latitude lines "sag" to the south so a straight line will tend to be the great circle route. You really need to look at an east west route through TWO sectionals 400 miles or so to see it. Yes, if you want to try and "proove" that this is not so, you can, it wont be an exact great circle except at one bearing. Point is, there are many, many different "projections"
 
Thank!

I'll look for those sagging lines next time I have a physical sectional in front of me.

It's not something I think I ever noticed, nor do I recall having been exposed to it before, or teaching it in the navigation courses I taught.

But it's never too late to learn something new!
 
For the flat-earthers: Ask one of them to tell you the distance between SFO and DCA. And don't let them use any formula that relies on 3D coordinate systems. Chances are, they'll grab a map and draw a straight line, then read off the scale. Fine - tell them that map is a projection of a sphere on a piece of paper and that they need to try again. They'll tell you the mapmakers are part of a conspiracy. Fine. Draw that straight line, then draw the GC route. The FE will say, "That's stupid. Look how much longer it is." OK, then mark down cities along each route. Go into Google Earth and start adding up the distances between each city. Then listen to them explain that Google Earth is part of the conspiracy. (It might take most of the day.)

Here's a mapper:

http://www.gcmap.com/mapui?P=DCA-SFO&PC=#ff0000&RC=#000080&DU=nm&SU=kts

It lets you switch to about 4 or 5 projections.
 
FastEddieB said:
Thank!

I'll look for those sagging lines next time I have a physical sectional in front of me.

It's not something I think I ever noticed, nor do I recall having been exposed to it before, or teaching it in the navigation courses I taught.

But it's never too late to learn something new!
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If you have two adjoining sectionals, try to match them up side to side. You'll see it there, too.

Or go into WingX and find an airport that's very close to the edge of a sectional and look at how roads, power lines, airways, and latitude lines cross that gap.
 
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James331 said:
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This unfortunately is the truth. I went way to far down this rabbit hole a year or two ago. Arguing with a Flat-Earther is like trying to convince and Atheist to believe in God, or a believer to be an atheist. They believe that the earth is flat so strongly that they will ignore all evidence that proves them wrong and cling to any miniscule shred of evidence that they think might possibly support their claim. It is an impossible battle. You will end your experience with nothing but frustration and aggravation.
 
I've heard about flat earthers, but never looked into it. Where do they say the edge is, and do they have pictures? I would love to see it.
 
QuiQuog said:
I've heard about flat earthers, but never looked into it. Where do they say the edge is, and do they have pictures? I would love to see it.
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They believe the earth is a flat disc. "Antarctica" is actually a giant ring of ice around the disc. They call this the "Ice Wall" The North Pole is at the center of the disc. They believe there exists a giant inter-government conspiracy between America, Russia and China to hide "the truth" from the citizens of the world about the earth being flat. They believe various military agencies patrol the Ice Wall and will kill anyone that gets close to it. NASA is completely in on this, and all evidence of space flight has been fabricated by NASA including every space flight, space walk, and moon landing. No one has pictures or evidence of any of this because any that have attempted have been killed by the military.

I am telling you, these people will not listen to reason, and they will fabricate any thought or idea necessary to maintain their belief that the Earth is flat. They believe this is a conspiracy at the highest levels and that it is pervasive throughout all world governments including the United Nations.

In order to maintain my own sanity, I had to disengage from researching what their "beliefs" are. Just typing this up is causing my blood pressure to increase and give me a headache. I kind of got back into this recently because my Brother-in-Law recently became a "Flat Earther".
 
QuiQuog said:
I've heard about flat earthers, but never looked into it. Where do they say the edge is, and do they have pictures? I would love to see it.
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Well, since the earth is flat, the oceans would run off the edge. To prevent that, there happens to be a big ice wall all the way around, called Antarctica. What's beyond that ice wall, you might ask? No one has traveled beyond it and lived.

You can look up the Flat Earth Society online. They even have a forum.

My geography professor said he always wanted to join, figured it would look good on his resume.
 
azpilot said:
In order to maintain my own sanity, I had to disengage from researching what their "beliefs" are. Just typing this up is causing my blood pressure to increase and give me a headache. I kind of got back into this recently because my Brother-in-Law recently became a "Flat Earther".
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Kind of the way I felt last winter arguing with a climate change denier on here. The thing is, there were points where we actually agreed, but he kept trying to prove that there was no such thing as the greenhouse effect using arguments a 12th grader could ride a tank through. At some point you just have to disengage to, as you put it, maintain your sanity and, I would add, stop wasting precious time.
 
azpilot said:
They believe the earth is a flat disc. "Antarctica" is actually a giant ring of ice around the disc. They call this the "Ice Wall" The North Pole is at the center of the disc. They believe there exists a giant inter-government conspiracy between America, Russia and China to hide "the truth" from the citizens of the world about the earth being flat. They believe various military agencies patrol the Ice Wall and will kill anyone that gets close to it. NASA is completely in on this, and all evidence of space flight has been fabricated by NASA including every space flight, space walk, and moon landing. No one has pictures or evidence of any of this because any that have attempted have been killed by the military.

I am telling you, these people will not listen to reason, and they will fabricate any thought or idea necessary to maintain their belief that the Earth is flat. They believe this is a conspiracy at the highest levels and that it is pervasive throughout all world governments including the United Nations.

In order to maintain my own sanity, I had to disengage from researching what their "beliefs" are. Just typing this up is causing my blood pressure to increase and give me a headache. I kind of got back into this recently because my Brother-in-Law recently became a "Flat Earther".
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This sounds cool. I will have to look into joining this movement. Thank you.
 
azure said:
Kind of the way I felt last winter arguing with a climate change denier on here. The thing is, there were points where we actually agreed, but he kept trying to prove that there was no such thing as the greenhouse effect using arguments a 12th grader could ride a tank through. At some point you just have to disengage to, as you put it, maintain your sanity and, I would add, stop wasting precious time.
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azure, I am not trying to take anything away from what you're saying, and I like your analogy, but let me paint a picture for you.

Imagine that it's 1,000 years from now. The ice caps have melted and we are living in Kevin Costner's "Water World". At this point, you have an argument with someone over global warming. He then tries to explain this was all a government conspiracy and that the Earth has ALWAYS been covered in water. That is what a conversation with a flat earther is like.
 
This is the video that started me down the rabbit hole...

 
That little cartoon dude at the beginning looked like me walking up Lombard St in SF.

And that's as much as I watched.
 
EdFred said:
Not this again.

Simple demo, take a matchbox car and roll it over the surface of a basketball, does the car ever end up upside down in relation to the surface of the basketball?

Same thing with a plane.
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This is a red herring and has nothing to do with gyroscopes.

EdFred said:
Only because the basketball isn't the center of gravity for the gyroscope. Your friend is looking at things from the wrong frame of reference. If you stood back and could see all the planes airborne at any time, you would see that they were at various pitches and attitudes for your frame of reference, but all of them (that are straight and level flight) would have their bellies - and the earth side of the gyroscope - closer to the surface of the earth than their canopies or sky side of the gyroscope.
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As someone else mentioned, the pendulous vanes help orient the attitude indicator with respect to gravity. The heading indicator on the other hand, will precess as much as 15° per hour (360°/24 hours), because of the gyroscopic property rigidity in space not rigidity with respect to the earth's surface.

FC_PAGE_130_FIGURE_19G3.jpg
 
dmspilot said:
This is a red herring and has nothing to do with gyroscopes.
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You missed the previous thread where the planes also had to end up upside down in relation to the earth if they fly straight and level. The matchbox/basketball is a completely accurate analogy in that regard.
 
For the flat earthers - if the earth is flat, how is is daytime in the US and nighttime in Hong Kong/India? Or is everyone on the other side of the world in on the conspiracy as well?
 
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irhologram said:
Please view and discuss this YouTube conversation between an Air Traffic Controller and a Flight Instructor on this topic.
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Oh my gosh. I listened to this while driving to work over the past few days. It was entertaining because these guys are nut jobs.

They noted, in conspiratorial tones, that the government tells us that there are 24 GPS satellites when in fact that there are 36 or more. Oh my god.

The former controller specifically asserts that the world is flat because he saw aircraft on his scope that were over 350 miles away at 81,000 feet and there's no way he could see them on his scope if the world were round.

At one point the controller notes that Albert Einstein had an IQ of 164, whereas he the controller has an IQ of 197 and "a day-to-day operational IQ" of 174 because he has two measurable IQs. Whatever.
 
EdFred said:
For the flat earthers - if the earth is flat, how is is daytime in the US and nighttime in Hong Kong/India? Or is everyone on the other side of the world in on the conspiracy as well?
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EdFred, I'm telling you, don't use reason. It won't work. They have an excuse for every possible explanation you can come up with. If they don't have an excuse, they'll just go on some pseudo-science rant and talk about nothing. You'll end up banging your head against the wall, and walk away frustrated.
 
Also, this isn't in the FAA test set, so some pilots get it taught to them and some don't. The latitude tick marks on the longitude lines are 1 nautical mile apart, which BTW is one minute of angle from the center of the earth. So no need for a scale ruler to measure distances, just use a piece of paper and put it on the longitude and count it up....

Then there is the one about Constant Speed Props, but I wont go there....
 
Yes, the LCC gets reasonable good angular computation for the sake of distorting distances.

My favorite discussion of map projections:

map_projections.png
 
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Back to the attitude indicator's levelling: Gravity moves those pendulum valves to let air out of the gyro case at one of four exits, causing a thrust that erects the gyro relative to the center of the earth. The gyro wheel itself is fixed with respect to space. The wheel will remain, in the short term, level with the earth's surface as the airplane maneuvers so that it will indicate the horizon properly. Do an extended steep turn (around and around), however, and it will try to level itself with the airplane, since the case is lined up with the earth's surface while the centrifugal force of the turn moves the valves and confuses them.

In most light airplanes the air is sucked out of the instrument's case, while air coming in goes through the gimbal frame to the gyro wheel case itself and is drawn out of the wheel case via those little valves, and then out to the vacuum pump.
 
On a marginally related note, did everyone know that VOR courses are actually great circle routes (ignoring scalloping and other local anomalies)? When I first started flying with LORAN I was under the mistaken impression that LORAN (and now GPS) presented GCRs and VOR navigation was Rhumb Line based (constant heading) but I later discovered that VOR radials were just as curved. It just didn't seem that way due to the VOR distance limitations.
 
gismo said:
On a marginally related note, did everyone know that VOR courses are actually great circle routes (ignoring scalloping and other local anomalies)? When I first started flying with LORAN I was under the mistaken impression that LORAN (and now GPS) presented GCRs and VOR navigation was Rhumb Line based (constant heading) but I later discovered that VOR radials were just as curved. It just didn't seem that way due to the VOR distance limitations.
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Wait, what? Are you trying to imply that they're bending the RF...?
 
mkosmo said:
Wait, what? Are you trying to imply that they're bending the RF...?
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I think what he's saying is, the RF itself will naturally follow the "great circle" route anyway, since it's going to be radiating the shortest possible distance between two points (ignoring multi path and scattering and refraction in the ionosphere and slant angle and lord knows what else, of course...).

He's talking that it would be a single line direct line between you and the station. And since you and the station are on a round ball...

If you flatten that out to a map projection, it'll look curved. On paper. Not in the real world.

The radials are all "great circle routes" so to speak.

That's how I'm reading him. Now I'm trying to jive that with what happens when you use a straightedge on a chart to plot a line from the VOR outward. If that line really should be slightly curved, it means there's an error in the line the further you are from the station.

Thinking... Hmm. Fun.
 
denverpilot said:
He's talking that it would be a single line direct line between you and the station. And since you and the station are on a round ball...

If you flatten that out to a map projection, it'll look curved. On paper. Not in the real world.

The radials are all "great circle routes" so to speak.
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This.

The part I bolded is the crucial point. Great circles are only curved insofar as they have to be to follow the Earth's curved surface. If you draw a straight line (straight in space) from the antenna to your airplane, and at each point on that line draw a vertical line down to the surface, the path it traces on the surface will be a great circle.

Anyone who doesn't believe that great circles are "straight" should take a globe and stretch a string from NY to SF. Compare that path with the great circle route plotted by SkyVector or ForeFlight. You'll find that they match, certainly to the accuracy of your ability to judge
 
azure said:
Anyone who doesn't believe that great circles are "straight" should take a globe and stretch a string from NY to SF.
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This is the way I have always understood great circle routes. I had no idea there was so much of a controversy about it.
 
I just had my first cup of coffee, but I think I just realized you could install a VOT transmitter at the magnetic North Pole -- and it would be correct for navigation purposes.

Just have to move it slowly as the magnetic pole moves. LOL!

[Edit: South Pole argh. Well you get the idea anyway...]
 
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Everskyward said:
This is the way I have always understood great circle routes. I had no idea there was so much of a controversy about it.
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No controversy, but some people who are used to looking at curved routes on a map seem not to understand them. (Not sure if the poster denverpilot was responding to was one of them, or was just being flip.)
 
Back to projections and great circles. Is it possible to fly say, from New York to Paris, on a single compass heading and if so what kind of course would that be on a map, or on a globe?
 
Silvaire said:
Back to projections and great circles. Is it possible to fly say, from New York to Paris, on a single compass heading and if so what kind of course would that be on a map, or on a globe?
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No. If nothing else because the magnetic pole isn't colocated at the actual pole.
 
Silvaire said:
Back to projectionsnm

nd great circles. Is it possible to fly say, from New York to Paris, on a single compass heading and if so what kind of course would that be on a map, or on a globe?
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The shortest route is a straight line, like this:

http://www.gcmap.com/mapui?P=LGA-lys&MS=wls&MP=o&PC=red&RC=navy&DU=nm

and this:

http://www.gcmap.com/mapui?P=LGA-lys&MS=wls&MP=a&PC=red&RC=navy&DU=nm

Of course, it isn't really straight in 3 dimensions because it follows above th surface of the earth. To be truly straight would require a hellacious tunnel.

Would that require a single compass heading? Or would deviations change enough to require adjustments as you go?
 
Silvaire said:
Back to projections and great circles. Is it possible to fly say, from New York to Paris, on a single compass heading and if so what kind of course would that be on a map, or on a globe?
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Roughly 081° & 3090.9 nm, off the top of my head. It's called a rhumb line.

dtuuri
 
Silvaire said:
Back to projections and great circles. Is it possible to fly say, from New York to Paris, on a single compass heading and if so what kind of course would that be on a map, or on a globe?
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Yes, that's called a Rhumb Line. Such a path will normally be longer than a GCR (exceptions are when flying directly north or south (magnetic) or following the magnetic equator.
 
Thinking about it, I see how that works.

Silly comment about the location of the pole. The heading is simply adjusted to average the change out. Duh. Ha.

It's a slow brain day here on the prairie.
 
What helped me understand it was to stop thinking of the earth as a flat map and start thinking of it a sphere of solid geometry. Everything is based off the center of the earth. Need to study some solid geometry. With R fixed, any point can be expressed as a lat and long, which is an r long vector coming from the center of the earth to a point on the surface.

360 degrees, 60 minutes in each degree. One minute of angle is one nautical mile at the equator and on ALL lines of longitude. Get a globe and put it in the corner of the room. Any flat map distorts. Think about trying to paste a flat piece of paper to an orange.

360 * 60 = 21600 which is the circumference of the earth in nm AND the number of minutes of angle around that circumference. ETC

ETC.
 
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