Wrong burt, sorry. in reality my gyro would sense that turn. You cannot change true or magnetic north to your liking. Basically the turn you would do on a flat Earth does not match the curve you follow around a spherical one.
are you arguing whether the curve matches, or whether there is one; the curving on a round earth would be a lot less than one on a flat earth. or so I assume.
The curve you do on a sphere is of course going to be different then one you would make on a flat Earth. They are two completely different shapes and have two completely different navigational properties. Let me try to explain how navigators view True headings, magnetic headings, and the Earth.
True headings are independent of Earth in a way. I am not saying that we can judge north, south, east, and west in space, but true north is based on celestial objects that do not change with the Earth. Magnetic north is always changing, the rotation of the Earth on it's tilted axis. We use true headings so that we can maintain our track line easier. I do not know what you think you know, but if we have a track line that is at 086 true we will follow that track line at 086 true, we will not go in any other direction. If I need to sail from San francisco to Mito I know that I need to travel west. Mito is around a 250 true from San Fran, I can now make a series of leg's in that general direction ranging from 280-220, is it not possible to just go straight to Mito because the Earth is of course a sphere, I will curve in an arc like fashion as I travel around it. In no way will I make a circle just an arc. and A pretty small arc at that. If you try to do the same thing on a flat Earth map your semi circle that you have to make is flippen crazy. You basically are keeping your prop at right standard for the duration of the voyage. Also take a look at the circle you would do on a flat Earth, now look at the curve you make on a sphere.. they are flip flopped. You would not do and upside down arc to get across the north pacific, you would do that if you were on the south pacific!
I know that because on a flat plane you cannot make a circle without turning. It is geometrically impossible to make a circle on a flat object without turning. On a sphere, however, it is completely possible to travel in an arc without needing to turn, it is simply the shape of a sphere that allows this to happen. Can you say that on a flat plane you can make a semi circle or a full circle without turning? you can walk in one direction and create a circle? Do you understand how silly that sounds. Now ask yourself if walking around a sphere you can make a circle yes? If you walk around a portion of that sphere you more or less walk in an arc yes? not quite creating a circle, but you would if you walk in the same general direction without changing it dramatically (that would skew your circle and cause it to change paths on a sphere) If you are on a flat plane and you walk in a circle you are always changing your direction dramatically. If you decided to just keep walking as straight as you can possible make yourself walk you would now break that circle.
Now if you had a gyro in your hand calibrated to true north and you followed true north on a flat plan, why would you create a circle by stay at 000 true? on a sphere it makes perfect sense, you are going around an object, on a flat earth what are you going around to make that circle? the center of the flat plane? that is laughable because you have to turn to create that circle. True north is not some magical thing that defies the laws of geometry.
So just to clarify, to you Burt, no matter what these people say to you, take it from a navigator. If I tell you that if I am traveling to Mito Japan and on a westerly course of 250 true I am always going to be able to maintain 250 true, my magnetic compass should always come out to be 250 true after variation and deviation. I will not make a circle to get there, I will travel in a small arc only because I am on a sphere. If I were traveling on a flat Earth even though magnetic north is at the center making a semi circle as prominent as they show is not possible. The circle that you travel around a sphere is different from the circle you would travel on a flat plane.
If magnetic north/true north at the center of the flat plane no matter what you do, you have to turn. Even if your magnetic compass is showing that you are still going 270, you have to turn! that is such a conundrum it is not even funny. How do you explain turning without changing heading? impossible. On a tilted sphere going 270 you will travel in an arc (or curve whatever you want to call it that would eventually cause a circle) because 270 true is not 270 magnetic on Earth. the earth itself cuases you to create the arc,curve whatever great circle. so what the hell would cause you to do a circle on a flat plane without turning? Do you see what I am saying here burt? how is that possible to turn on a flat plane without changing heading... what is that flat plane doing? is it wobbling? tilting? rotating? flipping? what in the world is going on with that flat plane?