My gyroscope says the world is Flat

Swampfox201

Swampfox201

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Todd W.
Today a friend of mine sent me an observation from a conspiracy website.

The attitude indicator is a gyroscope. The gyroscope gives the pilot pitch and bank information by having the airplane move around the stationary gyroscope. If we depart the north pole and head south as we follow the curvature of the earth the plane should follow the curve which will throw the attitude indicator off to the point when we reach the south pole it will show the plane inverted.

He says this doesn't happen so the world must be flat.

Its not flat so why doesn't this happen?
 
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.
 
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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Nope but if you put a little tiny attitude indicator inside that matchbox car and drove it over the basketball it would show the car doing a loop as you made a revolution around the ball would it not?
 
Swampfox201 said:
Nope but if you put a little tiny attitude indicator inside that matchbox car and drove it over the basketball it would show the car doing a loop as you made a revolution around the ball would it not?
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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.
 
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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I understand what you mean by frame of reference but your answer seems to rely on the center of gravity of the earth. Let me ask this: If you put an attitude indicator in the international space station would it show straight and level when it is actually orbiting around the earth? Would the fact its in a zero G environment because its falling cause its gyroscope to act differently than a gyroscope of say a SR71 blackbird racing around the curve of the earth??
 
Swampfox201 said:
I understand what you mean by frame of reference but your answer seems to rely on the center of gravity of the earth. Let me ask this: If you put an attitude indicator in the international space station would it show straight and level when it is actually orbiting around the earth? Would the fact its in a zero G environment because its falling cause its gyroscope to act differently than a gyroscope of say a SR71 blackbird racing around the curve of the earth??
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I've gone 0-G in my airplane and the gyro never tumbled.
 
Doh.

The new husband of my wife's aunt (whatever that makes him to me) is big on conspiracy theories. He's still arguing with me about the idea of "Chemtrails" from airliners. For those of you who aren't familiar with this ridiculous idea, it basically goes that airliners are spraying mind control chemicals to aid the government in controlling our citizens.

He constantly posts stupid videos of condensation trails, or wingtip vortices as an airliner landed in fog (titled something like: "Pilot forgets to turn off his chemtrail system before landing").

So, while your friend may be convinced that the world is flat, and my guy is convinced that the airline industry is conducting a mass aerosol distribution of psychotropic drugs, I think it's safe to say that neither of these theories really hold ANY weight :)
 
If you have an ideal gyroscope, gravity doesn't affect it. If you fly 180 degrees around the world your gyro would indeed show you upside down with respect to how it was leveled when you started out.

The problem is that your attitude indicator is not an ideal gyroscope. To allow it to self-erect and compensate for precession effects gyros have devices that attempt over a longer period to return the gyro to a level indication. As a result, by the time you fly around the world, your gyro would have reset itself to the local "this way's up" indication.
 
flyingron said:
If you have an ideal gyroscope, gravity doesn't affect it. If you fly 180 degrees around the world your gyro would indeed show you upside down with respect to how it was leveled when you started out.

The problem is that your attitude indicator is not an ideal gyroscope. To allow it to self-erect and compensate for precession effects gyros have devices that attempt over a longer period to return the gyro to a level indication. As a result, by the time you fly around the world, your gyro would have reset itself to the local "this way's up" indication.
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Thank you! This is the answer I was looking for. I'll pass it on!
 
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.
Click to expand...

Gravity is physically indistinguishable from other accelerations. If the attitude indicator maintained its orientation relative to the apparent center of gravity, it would be just like a pendulum. It would thus be misled by centrifugal effects, which would defeat the whole purpose of an attitude indicator.

Ron's explanation is correct.
 
Obviously the correct explanation is that the world actually is flat and it's all been one great big hoax. Shhh, we're not supposed to talk about it.
 
acrophile said:
Gravity is physically indistinguishable from other accelerations. If the attitude indicator maintained its orientation relative to the apparent center of gravity, it would be just like a pendulum. It would thus be misled by centrifugal effects, which would defeat the whole purpose of an attitude indicator.

Ron's explanation is correct.
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I never said apparent center of gravity.
 
EdFred said:
I never said apparent center of gravity.
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I know. You referred to the actual center of gravity. But since gravity is physically indistinguishable from other accelerations, no device can orient itself toward the actual rather than apparent center of gravity. An attitude indicator is useful precisely because it ignores the direction of gravity (except, as Ron noted, for very gradual long-term corrections).
 
The thing that upsets me most is that you actually have to spend time dealing with this, and looking for an explanation that your friend will accept. The thing that sucks more is that your friend won't accept it. They will always find some other scientifically dubious comeback.
 
onezuludelta said:
The thing that upsets me most is that you actually have to spend time dealing with this, and looking for an explanation that your friend will accept.
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It's a worthwhile expenditure of time, because pilots are supposed to be able to explain the basics of how their instruments work. That knowledge helps understand what can go wrong.

The thing that sucks more is that your friend won't accept it.
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I doubt his friend actually believes the earth is flat.
 
I think the problem only applies to IMC, since those of us who fly VFR generally maintain a visual horizon. That might be the reason the Maylasian airliner disappeared - it flew off into space.
 
Please view and discuss this YouTube conversation between an Air Traffic Controller and a Flight Instructor on this topic.
 
Google local vertical, send him the links. Then have a beer.
 
Thnx, Sundancer, but not relevant to topics in the vid.
 
Another thing to think about are aircraft compass turns.

https://en.wikipedia.org/wiki/Aircraft_compass_turns

We learn about this during private pilot training. We learn that Aircraft compasses behave differently in the Norther Hemisphere and Southern Hemisphere. The compasses different behavior in the two hemispheres is a direct result of the fact that the Earth is generally spherical.

I used to work for a company that builds massive space rated gyroscopes to put on satellites. The gyros could be gimballed to generate an output torque on the satellite and change it's attitude. We built a mock satellite in our lab and suspended it at the CG on an giant air bearing. We would spin up the six gyros (each had a rotor that weighed about 150 lbs), to 6,000 RPM. As the day progressed the satellite appeared to rotate. In actuality, the mock satellite was remaining stationary while the earth rotated underneath it. If the attitude indicator in your airplane was "perfect" it would behave the same.

My Brother-in-Law just became a flat earther a month or two ago. I can no longer speak with him. All he can see in his life is black helicopters around every corner. It is quite maddening.
 
Does anyone have a link to a good explanation of great circle routes that airplanes take while flying long distances instead of straight lines? I can't find a simple easy to inderstand video on YouTube.
 
Swampfox201 said:
Does anyone have a link to a good explanation of great circle routes that airplanes take while flying long distances instead of straight lines? I can't find a simple easy to inderstand video on YouTube.
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How about a globe? Put a string from City A to City B and see what happens. There's no such thing as a "straight line" on a curved surface.
 
I fly a taildragger that when on the ramp has the forward/aft attitude about like a Vy climb. When the AI activates it has the same attitude forward/aft, approximately a Vy climb. When I level out the AI shows level. So whatever is going on in that AI, it knows about horizontal to the earth. It doesn't just adopt the current attitude as level, none of them do (what if you start on a slanted ramp?) and stay that way. If asked, you can always say "its precession". Anything not evident about how a gyro works, its always because of "precession".
 
irhologram said:
Thnx, Sundancer, but not relevant to topics in the vid.
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Was actually replying to the OP. . .but did (start) to view the vid, but life is too short for delusions, and checked out after a few minutes.

Still, I guess it's possible that hundreds of thousands of people, maybe millions, involved in astronomy, physics, space exploaration, Euclidian geometry, navigation,, etc., have kept a secret for a few centuries.

Or, maybe it was a goof and I didn't give it enough time? Punchline pops up later, maybe?
 
Swampfox201 said:
Does anyone have a link to a good explanation of great circle routes that airplanes take while flying long distances instead of straight lines? I can't find a simple easy to inderstand video on YouTube.
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https://en.wikipedia.org/wiki/Great_circle

The whole "flat earth" deal looks at a flat map, draws a straight line, and says, "There. Your stupid great circle routes don't make any sense." But that's because a flat map stretches out the surface of a globe and tries to convert 3D into 2D. It doesn't work like that in the real world. If you took a straight line from a flat map and transposed it on a 3D globe, then YOU can say, "There. Your stupid straight line routes don't make any sense."
 
Matthew said:
https://en.wikipedia.org/wiki/Great_circle

The whole "flat earth" deal looks at a flat map, draws a straight line, and says, "There. Your stupid great circle routes don't make any sense." But that's because a flat map stretches out the surface of a globe and tries to convert 3D into 2D. It doesn't work like that in the real world. If you took a straight line from a flat map and transposed it on a 3D globe, then YOU can say, "There. Your stupid straight line routes don't make any sense."
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If you want to draw straight lines on a 2D map use a Mercator projection. Then it works. The way I think of it is taking a plane and sticking it through the two points on the surface of the globe and then through the center point of the globe. If you do that and see the path across the surface where the plane intersects that's a great circle route.

John
 
But wouldn't that Mercator need to be "centered" along your route? (On that projection, the only great circle route is at the equator.) There are ways to do it. Heck, even if you go into any GPS app and plan a flight between two distant airports you'll see the curved line displayed over the sectionals.
 
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The sectionals have curved lines of latitude (they sag to the south), so a direct route IS a straight line. Yes, depends on the projection.
 
coloradobluesky said:
The sectionals have curved lines of latitude (they sag to the south), so a direct route IS a straight line. Yes, depends on the projection.
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The Lambert Conformal Conic Projection:

en.wikipedia.org/wiki/Lambert_conformal_conic_projection

>>>
Pilots use aeronautical charts based on LCC because a straight line drawn on a Lambert conformal conic projection approximates a great-circle route between endpoints for typical flight distances.
<<<

I just got into Garmin Pilot and drew a course from LAX to LGA. Of course, it crosses many sectionals. You can see a slight curve. If I try to straighten it a bit by putting a waypoint on Kansas City, it adds about 20nm.

I'm going to try plotting that course in a couple of different projections.
 
Bringing up sectionals on my iPad using WingXPro7, lines of latitude appear perfectly straight at any scale.

Choosing two distant airports pretty much on a line of latitude, a line bowing upwards is drawn, which I assume approximates a Great Circle Route.

24639791063_8d3b179c76_z.jpg


That does not seem to jibe with coloradobluesky's assertion that straight lines approximate Great Circle Routes on a sectional.

Right?

Good hijack, though! Had not thought about this stuff for a long time.
 
FastEddieB said:
Bringing up sectionals on my iPad using WingXPro7, lines of latitude appear perfectly straight at any scale.

Choosing two distant airports pretty much on a line of latitude, a line bowing upwards is drawn, which I assume approximates a Great Circle Route.

24639791063_8d3b179c76_z.jpg


That does not seem to jibe with coloradobluesky's assertion that straight lines approximate Great Circle Routes on a sectional.

Right?

Good hijack, though! Had not thought about this stuff for a long time.
Click to expand...

It does jibe.

That projection works pretty well until you do long legs. The chart is curved, so your "curved line" (great circle) is canceled out and looks straight. It isn't perfect. Use wingx and plot a course ftom SFO to DCA. They are approx the same latitude, but for a great circle, shortest distance, the course will have to curve upward.

I couldn't find a utility that draws the same course on different projections.
 
Is your course on the same sectional? If you use a straight edge plotter you'll probably be pretty close. I think wingx and other tools draw the true great circle route, where your plotter will draw a straight line that aproximates it because of the way the sectional is drawn.
 
I need to compare a sectional of northern AK with southern TX to see what the differences look like long the edges.
 
FastEddieB said:
But he said a straight line would approximate a Great Circle Route. It does not appear to.
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It tries to. there is always a trade off. If you have a chart that really does compensate then your plotter won't show correct distances. There is no perfect way around it.
 
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