[Tom Bishop]

It says that the last 3D model you posted is "computed from" the gravity field model. It's not actually a 3D spherical model.

So ....

How would someone make a 3D Spherical Model such that it would satisfy you (since you're not happy with one computed as above), and which could be rendered in viewable form on your computer screen?

The one Stack posted isn't even what the RE looks like in RET and is wildly incorrect. This is widely known about that image which is regularly posted here. Not sure how you missed this.

https://ourplnt.com/earth-without-water/

It says that the last 3D model you posted is "computed from" the gravity field model. It's not actually a 3D model.

I don't know what you mean. The DTED (or Digital Terrain Elevation Data) used for specific targets uses the EGM96 Geoid, which, in turn, was created from a Gravity field model. You're depiction of the Geoid is a mercator projection. Mercator projections come from a globe source. Not to mention, a gravity model. There's no mystery there.

As far as your comment regarding SAMS versus Tomahawks, I'm not sure why that matters. Looks like SAMS uses IMARS and Tomahawks use TRAMS (TECHNICAL RADAR ANALYSIS MODELING SYSTEM). Again, the document that was in the video references, regarding the Tomahawk TRAMS:

"The simulations use radar range equations to determine the radar performance. Included in the model are multipath calculations, clutter effects, attenuation, and detailed antenna representation. The flyby simulation incorporates the option to use either digitized terrain information from the Digital Terrain Elevation Database (DTED) provided by the Defense Mapping Agency or a simple spherical Earth model."

So the Tomahawk, using TRAMS, utilizes the same DTED Geoid as the SAMS IMARS or a "simple spherical Eath model".

The document says that TRAMS is used only for simulating one-on-one encounters. It does not state that the Tomahawk travels 1500 miles based on this.

[stack]

It says that the last 3D model you posted is "computed from" the gravity field model. It's not actually a 3D spherical model.

So ....

How would someone make a 3D Spherical Model such that it would satisfy you (since you're not happy with one computed as above), and which could be rendered in viewable form on your computer screen?

The one Stack posted isn't even what the RE looks like in RET and is wildly incorrect. This is widely known about that image which is regularly posted here. Not sure how you missed this.

https://ourplnt.com/earth-without-water/

It's a gravity model. Used by the Tomahawk TRAMS and SAMS IMARS. Unless the document in your video is wrong.

It says that the last 3D model you posted is "computed from" the gravity field model. It's not actually a 3D model.

I don't know what you mean. The DTED (or Digital Terrain Elevation Data) used for specific targets uses the EGM96 Geoid, which, in turn, was created from a Gravity field model. You're depiction of the Geoid is a mercator projection. Mercator projections come from a globe source. Not to mention, a gravity model. There's no mystery there.

As far as your comment regarding SAMS versus Tomahawks, I'm not sure why that matters. Looks like SAMS uses IMARS and Tomahawks use TRAMS (TECHNICAL RADAR ANALYSIS MODELING SYSTEM). Again, the document that was in the video references, regarding the Tomahawk TRAMS:

"The simulations use radar range equations to determine the radar performance. Included in the model are multipath calculations, clutter effects, attenuation, and detailed antenna representation. The flyby simulation incorporates the option to use either digitized terrain information from the Digital Terrain Elevation Database (DTED) provided by the Defense Mapping Agency or a simple spherical Earth model."

So the Tomahawk, using TRAMS, utilizes the same DTED Geoid as the SAMS IMARS or a "simple spherical Eath model".

The document says that TRAMS is used only for simulating on-on-one interactions. It does not state that the Tomahawk travels 1500 miles based on this.

I don't know what 1500 miles or one-on-one has to do with anything. The long and short is that the document says that Tomohawk simulations when targeting something specific, use TRAMS which is based on digitized terrain information from the Digital Terrain Elevation Database (DTED - A geoid) provided by the Defense Mapping Agency or a simple spherical Earth model.

Unless the document is wrong, I'm not sure what else there is to add.

[Gonzo]

Fortunately I didn't say it was a course for pilots. I merely said that it supported it.

Can you explain why you say this?

pilots are taught to fly over a FE, as demonstrated in that guide from a flight dynamics course.

and pilots are taught to fly, over a flat, non-rotating earth.

The fact that the plane is built to fly over an FE

This is all nonsense. Again, what is your aviation background? Aerodynamicist? Pilot? Aerostructure engineer? I mean to make such statements one hopes you have some formal training and experience, to be able to say the things about pilot training and aero engineering as you are.

[DuncanDoenitz]

When learning any skill, the syllabus should reduce the number of ancillary variables to the minimum possible in order to teach the particular skill being taught. Learning to drive a road vehicle, the student's first experience will probably be driving around a deserted car park.  This in no way denies the existence of road junctions, motorways, opposing traffic; it merely permits attention to the initial skills of steering, clutch, gear changing and so on. 

As skills are mastered, new variables are introduced until the student learns all the skills necessary, subject to his ability to master them.  The graduate knows of the further existence of trailers, tracked-vehicles, heavy goods vehicles, but only needs to learn those skills if his job or interests require it. 

So with flying; the basic student does not need to consider Earth curvature, so it can be ignored up to the skill and licence required of a private pilot.  This does not deny the existence of intercontinental travel, but global navigation knowledge only becomes necessary if the pilot has the intention, and ability, to pilot himself over global distances. 

[Action80]

Is anybody actually seriously holding this up as proof of a FE?

Where does it say proof?

Well, aside from the title of the video you posted immediately below this question, and in the link on the page we are discussing, I had rather assumed that, given it was in the 'Flat Earth wiki', you were using it in your evidence pile for reasons the earth is flat, just as the creator of the video you linked to is doing.

Do you understand the different meanings of the words, "proof," and, "evidence," and if so, why do you like to throw one in place of the other so much?

[Action80]

Well, let's get our facts straight here, as you seem to be confusing a few things. That flight dynamics course is not for pilots, but rather undergraduate aeronautical engineers.

Did I say that the document it was for pilots, or did I say it supported it?

You said:

that pilots are taught to fly over a FE, as demonstrated in that guide from a flight dynamics course.

That's not a course for pilots. It matters not, to be honest - I just thought you might be open-minded and interested in accuracy / learning something new rather than just being defensive.

Are pilots prohibited from attending the course?

What's your point?

[Action80]

N.Pavlis also has the 3D representation of the Geoid (2008):


Geoid height, computed from the gravity field model EGM2008 (Pavlis et al., 2012).

Tell us all, where do the gnomes, fairies, and ogres live on this marvelous place you provide?

I cannot believe you accept this crap as reality.

[Gonzo]

Is there any reason why the articles on aerostudents.com that refer to the globe aren't quoted? There are quite a few that refer to orbital dynamics too. Even that Flight Dynmics article goes on to talk about reference frames with an axis coming from the center of the Earth.

[Action80]

Is there any reason why the articles on aerostudents.com that refer to the globe aren't quoted? There are quite a few that refer to orbital dynamics too. Even that Flight Dynmics article goes on to talk about reference frames with an axis coming from the center of the Earth.

Feel free to quote the references to "the globe," if you feel you are being slighted by their absence here in this thread.

I don't think you understand reference frames, if you are referring to this: "First, let’s examine the inertial reference frame F_I. It is a right-handed orthogonal system. Its origin A is the center of the Earth. The Z_I points North. The X_I axis points towards the vernal equinox. The Y_I axis is perpendicular to both the axes. Its direction can be determined using the right-hand rule."

[AATW]

Is there any reason why the articles on aerostudents.com that refer to the globe aren't quoted?

Of course there's a reason. Tom cherry picks to suit his agenda.

All he's got in that Wiki page is a one off letter sent in by someone who claims to be someone. It's interesting to note his incredulity in this thread when jimster related a conversation he had with someone who wrote software which uses spherical geometry equations. Compare and contrast that with the credulity he shows about a letter which someone wrote in to a magazine in 1979 which happens to fit his agenda.
And then the Wiki page cites a document which describes a flat earth as a "simplifying assumption".  Simplifying assumptions are, by definition, things which are not true. But they make the model simpler and so long as the differences are negligible then they can be made. Other "simplifying assumptions" are that "the aircraft has constant mass" and "there is constant wind". These things are also not true, they're just simplifications to make the model and maths easier, like spherical cows ( https://en.wikipedia.org/wiki/Spherical_cow ). If the earth were flat then they wouldn't have to name it as a simplifying assumption, the fact it's mentioned as a simplification is evidence for a globe.
There's also a whole section in that document about the force of gravity. That is conveniently ignored.

[SteelyBob]

This is really simple stuff - if it's short time frames or short ranges, then FE is a valid simplifying assumption. If the time period is long, or the ranges large, then it isn't. Do you understand that concept?

The Tomahawk's 1500 miles isn't a long enough range?

The Tomahawk's range is irrelevant in the context of what is being discussed in that document. Again, you are merely demonstrating a lack of understanding of the subject matter that you yourself brought up.

Well aware of Tomahawk performance, thanks. Again, you are embarrassing yourself by wading into territory you clearly don't understand properly. I'll say it again - we are talking about a SAM engaging a cruise missile - the range of the cruise missile in that context is irrelevant.

If the Tomahawk isn't accounting for curvature, and there is curvature, I don't see how it can run precision maneuvers against SAMS hundreds of miles away without knowing where it is above the earth.

Your lack of comprehension should not be confused for being an argument.

Again, read the document carefully. The situation being modelled in that section is a simple engagement of a Tomahawk missile by a SAM - the Tomahawk is on its way to some other target somewhere, and the SAM is trying to shoot the Tomahawk down, not the other way round as you suggest above. It's stunningly obvious if you just read it - it's right there in the intro:

Detailed one~on~one engagement simulations that model the performance of individual radars and surface~to~air missiles against a single Tomahawk are fundamental to this process.

In order to model that, they have to model both the detectability of the Tomahawk (ie can it be seen by radar, and when) and then the actual engagement itself, and then the survivability of any impact or explosion. A multi-step process. For the detectability, they use a radar model called TRAMS:

For the detectability analysis, several land~based radar modeling tools are available. One model is the Technical Radar Analy i Modeling System (TRAMS), which simulates a one~on~one encounter between an airborne vehicle (in this case a Tomahawk missile) and a single land~ba ed radar

To be clear, TRAMS doesn't have a flat earth assumption built in - it can use spherical or DTED models. That is to be expected for a radar detection model, as the earth's curvature versus radar antenna elevation and target height is critical in the detection. It later says:

The flyby simulation incorpo- rates the option to use either digitized terrain information from the Digital Terrain Elevation Database (DTED) provided by the Defense Mapping Agency or a simple spherical Earth model.

The latter spherical model would result in 'flat' terrain, but that isn't the same as thing as a flat earth assumption.

Following detection, the next step is modelling the actual engagement, for which they use IMARS. IMARS does have a flat earth option, or another, more sophisticated round-earth DTED. The FE assumption is understandable in this context, as by definition detection has already occurred, so radar horizon is not a factor.

IMARS outputs a miss distance (between the SAM and the Tomahawk), which is then fed into another model, MECA, which is used to figure out if the Tomahawk survives the engagement or not.

Later in the document this process is used in simulated large scale, multiple missile engagements, but the section we are discussing is just really simple, local 1v1 engagements.

My source for the above is merely the evidence you presented us with. Do you see where you went wrong now?

[Action80]

The latter spherical model would result in 'flat' terrain, but that isn't the same as thing as a flat earth assumption.

You are correct.

If you get "flat," then it is FLAT and you assume nothing.

It is rendered AS IT TRULY IS!

[Gonzo]

Of course there's a reason. Tom cherry picks to suit his agenda.

All he's got in that Wiki page is a one off letter sent in by someone who claims to be someone. It's interesting to note his incredulity in this thread when jimster related a conversation he had with someone who wrote software which uses spherical geometry equations. Compare and contrast that with the credulity he shows about a letter which someone wrote in to a magazine in 1979 which happens to fit his agenda.
And then the Wiki page cites a document which describes a flat earth as a "simplifying assumption".  Simplifying assumptions are, by definition, things which are not true. But they make the model simpler and so long as the differences are negligible then they can be made. Other "simplifying assumptions" are that "the aircraft has constant mass" and "there is constant wind". These things are also not true, they're just simplifications to make the model and maths easier, like spherical cows ( https://en.wikipedia.org/wiki/Spherical_cow ). If the earth were flat then they wouldn't have to name it as a simplifying assumption, the fact it's mentioned as a simplification is evidence for a globe.
There's also a whole section in that document about the force of gravity. That is conveniently ignored.

Quite.

Cognitive dissonance on a massive, if not global, scale, one might say.

If one quote from one chapter of one study resource from an introductory course in a university in The Netherlands, and one random letter that is, in fact, talking about the celestial sphere, are all the cherries to be found regarding flat earth in aviation....well, they must be pretty dry and shrivelled up by now.

More than happy to be corrected by Action80 and Tom as to their aviation experience where they were taught how to 'fly over a flat earth'.

[Gonzo]

A little ps to this thread.

The wiki states:

Royal Air Force College
Taking wrong directions would obviously have dire consequences when flying supersonic in a combat jet, therefore the Royal Air Force teaches their pilots the “real thing”. From the Aug 16, 1979 issue of New Scientist (Archive) we read on p.543:

Earthly

  “  Andrew Hill ("Darwin rules—OK?", 12 July p 127) says "...even in the Spectator, we rarely find serious assertions that the Sun goes around the Earth".

One can of course believe anything one likes as long as the consequences of that belief are trivial, but when survival depends on belief, then it matters that beliefs correspond to manifest reality. We therefore teach navigators that the stars are fixed to the celestial sphere, which is centered on a fixed earth and around which it rotates in accordance with laws clearly deducible from common sense observation. The Sun and the Moon move across the inner surface of this sphere and hence perforce go around the earth. This means, that students of navigation must unlearn a lot of the confused dogma they learned in school. Most of them find this remarkably easy, because dogma is as it may be, but the real world is as we perceive it to be.

If Andrew Hill will look in the Journal of Navigation he will f‌ind that the Earth-centred Universe is alive and well, whatever his readings of the Spectator may suggest. ”
                  —Darcy Reddyhoff, Royal Air Force College

Ignoring the fact that the wiki confuses RAF pilot training with the Royal Institue of Navigation's journal (let alone using an unverified claim about that journal!), I decided to do a little research on RAF pilot training as it's not too far away from my own study for my MA.

I visited the RAF Air Defence Museum at RAF Neatishead in the UK. On display there they have the RAF Navigation Manual used at the time the quoted letter was written.

I had a look. No mention of flat earth, or anything that could be construed to be describing such.

Plenty of mentions of globes and how to navigate on a globe earth, though.

Might be worth editing the wiki a little?

[Tom Bishop]

That quote is describing geocentricism, not FE. Those aren't always the same thing. Traditional geocentricism assumes an RE.

[Gonzo]

So therefore when the wiki claims that RAF pilots are ‘taught the right thing’, it means taught a globe earth?

Ok, glad we agree and have cleared that up then!

Might want to make it a little more clear, though.

The first paragraph needs amending then…

Aviation, or air transport, refers to the activities surrounding mechanical flight and the aircraft industry. Discussion on this topic revolves around the assertion that aircraft instrumentation are built to assume, and pilots are taught to fly, over a flat, non-rotating earth.

[Tom Bishop]

The statement behind that originally stems from the narrative of the wider Flat Earth movement. There are a number of videos of pilots saying that the they don't actually take Coriolis into account, that radar on F-15 jets go further that RE should allow, that their gyroscopes show level flight, and so on.

A RAF document saying that the earth is round, or even that it spins, is almost irrelevant and does not directly address how pilot are "taught to fly".

[Gonzo]

The statement behind that originally stems from the narrative of the wider Flat Earth movement. There are a number of videos of pilots saying that the gyroscope of their planes don't dip for curvature, that they don't actually take Coriolis into account, that radar on F-15 jets go further that RE should allow, and so on.

A RAF document saying that the earth is round, or even that it spins, is almost irrelevant and does not directly address how pilot are "taught to fly".

I humbly suggest referencing these videos (I note none of them are about pilots being taught to fly over a flat earth as the wiki claims), so we can discuss their merits, rather than the diversionary quote of the letter which you agree is unrelated to FE.

There’s no evidence provided on that page to show that pilots are taught to fly over a flat earth. Just a baseless claim.

[RonJ]

I personally took flying lessons for many years and rose up from being a private pilot to getting an instrument rating and then on to getting my commercial pilots license.  Never in all that training did I ever run across any written training material that referred to flying over a flat earth.  My flight instructors didn’t ever refer to the flat earth meme either.  I will admit that when in the cockpit operating an aircraft, that the shape of the earth is of little consequence.  When you are flying an instrument flight plan you will always try to maintain the altitude assigned to you by air traffic control.  This altitude is either a height above the ground or a height relative to a particular reference atmospheric air pressure, when maintaining a particular flight level.  In either case if the earth is a sphere, you are automatically following the curvature and it’s of a minor consequence and you never really know or care about it.  Even the long-haul pilots flying an over the ocean route wouldn’t consider the shape of the earth in their everyday activities.  Their flight route is gotten from a computer and all the pilots need to do is enter two points. 


Anyone using GPS is, by default, using an instrument whose accuracy depends upon the earth being spherical.  This fact is designed into the software that’s being used in every GPS system.  Everything that was previously done manually by a navigator using a sextant now is being done automatically by the software operating inside all GPS units and is completely hidden to the end user.  Certain commercial GPS units can output the raw data that you can download into your computer and do some spherical trig on to verify how the calculations are done if you have the time, knowledge, and desire to do so. 

[Tom Bishop]

The statement behind that originally stems from the narrative of the wider Flat Earth movement. There are a number of videos of pilots saying that the gyroscope of their planes don't dip for curvature, that they don't actually take Coriolis into account, that radar on F-15 jets go further that RE should allow, and so on.

A RAF document saying that the earth is round, or even that it spins, is almost irrelevant and does not directly address how pilot are "taught to fly".

I humbly suggest referencing these videos (I note none of them are about pilots being taught to fly over a flat earth as the wiki claims), so we can discuss their merits, rather than the diversionary quote of the letter which you agree is unrelated to FE.

There’s no evidence provided on that page to show that pilots are taught to fly over a flat earth. Just a baseless claim.

Actually, the Wiki does provide a number of links referencing that pilots say they are taught to fly over an FE -