Flying weather in New York in March

It's not really a trick question, but I think it's a difficult one.

"M" wrote in message
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On Mar 3, 3:18 pm, "Jon Woellhaf" wrote:

What fixed compass heading would hold to fly from JFK to SFO (assuming no
wind correction)?

Is it a trick math question? It's certain won't be the great circle
route, which has a continuous changing magnetic heading to hold.

Given the difference of magnetic variation between west coast and the
east coast, I'm not certain this can be calculated using a math
formula. Such a magnetic heading can be deduced by a computer
simulation using the brute force method.

"Jon Woellhaf" wrote in
:

It's not really a trick question, but I think it's a difficult one.

"M" wrote in message
oups.com...
On Mar 3, 3:18 pm, "Jon Woellhaf" wrote:

What fixed compass heading would hold to fly from JFK to SFO (assuming no
wind correction)?

Actually, I believe there are many right answers, but it largely depends on
how many laps one is willing to make around the globe before finally reaching
SFO...

If you wanted an approximation, start with a guess. look 50 miles
along that course line, note the deviation and variation at that point
and use it to calculate where you'd be for a 100 mile flight. Repeat
from that point about 30 times until you are abeam SFO. Now, since
that's about a 3000 mile trip, adjust your initial guess by 1 degree
for every 50 miles you're off, then try again. We used to call that
approach a numerical solution, or brute strength calculation, it
probably has a sexier name now.

There's a neat implication here. If you want to arrive within say 10
miles of your target after holding constant heading for 3000, your
heading has to really really be constant -- like to the tune of arc
tan (10/3000) or 0.2 degrees. That's a really tight tolerance to hold
on average.

Remember Linburgh arriving over Ireland within a few miles of where he
intended, after crossing the ocean? Lucky Lindy indeed!



going On Mar 4, 1:00 pm, "Jon Woellhaf"
wrote:
It's not really a trick question, but I think it's a difficult one.

"M" wrote in message

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On Mar 3, 3:18 pm, "Jon Woellhaf" wrote:

What fixed compass heading would hold to fly from JFK to SFO (assuming no
wind correction)?

Is it a trick math question? It's certain won't be the great circle
route, which has a continuous changing magnetic heading to hold.

Given the difference of magnetic variation between west coast and the
east coast, I'm not certain this can be calculated using a math
formula. Such a magnetic heading can be deduced by a computer
simulation using the brute force method.- Hide quoted text -

- Show quoted text -