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Flat Earth Theory / Wiki on aviation
« on: March 08, 2022, 09:49:25 PM »
The wiki has a small section on 'aviation', in which it quotes from, amongst other things, a flight dynamics book which lists a set of assumptions:

The wiki introduces this by saying:
...and concludes it by saying:
Is anybody actually seriously holding this up as proof of a FE? If you are an ardent FE believer then the first two assumptions are clearly something you believe to be true anyway, but the second two are demonstrably false. Aircraft are not of constant mass (they burn fuel and become lighter) and they are not rigid (as anybody who has observed the wings on an airliner bending will know). The list is therefore quite clearly, as it says itself, simplifying reality for the purposes of building a useful mathematical model of flight - mass changes can be neglected because they are relatively slow with respect to time and therefore don't effect the dynamics of flight. The earth can be treated as flat because, from a short-term modelling perspective, it makes very little difference.
Introduce navigation, and things get very different, just as if you want to discuss aerodynamic flutter, for example, then the rigidity assumption goes out the window. The assertion that instruments are built to assume a flat earth is demonstrably false - gyro based nav systems, for example, have to correct for transport and rotation errors. Likewise pilots are taught about globe navigation, great circles etc at an early stage in training.

The wiki introduces this by saying:
Quote
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.
...and concludes it by saying:
Quote
Note: The document does not go on to "unsimplify," to give its students accurate dynamics. The word 'coriolis', for instance, appears a single time.
Is anybody actually seriously holding this up as proof of a FE? If you are an ardent FE believer then the first two assumptions are clearly something you believe to be true anyway, but the second two are demonstrably false. Aircraft are not of constant mass (they burn fuel and become lighter) and they are not rigid (as anybody who has observed the wings on an airliner bending will know). The list is therefore quite clearly, as it says itself, simplifying reality for the purposes of building a useful mathematical model of flight - mass changes can be neglected because they are relatively slow with respect to time and therefore don't effect the dynamics of flight. The earth can be treated as flat because, from a short-term modelling perspective, it makes very little difference.
Introduce navigation, and things get very different, just as if you want to discuss aerodynamic flutter, for example, then the rigidity assumption goes out the window. The assertion that instruments are built to assume a flat earth is demonstrably false - gyro based nav systems, for example, have to correct for transport and rotation errors. Likewise pilots are taught about globe navigation, great circles etc at an early stage in training.