o fly a great circle, you have to constantly adjust
your heading. I still can't conceptually work out why


Consider a great circle route that takes you near the (North for example) pole.
A great circle, recall, is what a tight string between two points on a globe
describes. As you approach the pole, you will be travelling mostly North.
When you pass the pole you will be travelling mostly South. You need to change
headings somewhere! (You do so continually, although not at a constant rate)


If you had a WAC chart that displayed the entire Northern Hemisphere on one
chart, you could draw a straight line from Los Angeles to New York. Wouldn't
this be a great circle? And if it is, why couldn't you just fly the single
heading of that line?


Because that straight line is not a single heading. Note that the chart (and
the latitude lines) curve. If the latitude lines curve, a straight line must
change headings (unless it is a straight line going North South)


if you fly one by keeping a constant magnetic
heading between two points, does that mean you actually describe a curve
over the earth's surface?


In most cases yes. Consider lines of latitude, which have a constant heading
(90 degrees, or 270 degrees). Except for the equator, they are all curved.
You can do the same with "magnetic latitude" as with "true latitude"
(referencing the magnetic pole as opposed to the rotational pole) and it comes
out the same. You see this most easily near the pole, hence the puzzle "you go
South for one mile, East for one mile, North for one mile, and end up where you
started. You then see a bear. What color is it?"

Jose






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