In rec.aviation.piloting Mxsmanic wrote:
writes:
Where do you get a true north compass?
Aviation uses magnetic compasses less and less, and every other navigation
method works best with true north.
Total, utter, nonsense.
The use of magnetic north versus true north hasn't changed.
A sensor to find true north in an airplane in flight doesn't exist.
Your comment about magnetic south being unusable is just asinine.
Magnetic south isn't exactly the opposite of magnetic north on the Earth's
surface, so if one entity uses it, all must use it, or make constant
corrections to convert between the two. In fact, the failure of the line
between the poles to pass through the center of the planet introduces
additional complications into precise use of a compass. Not to mention the
many other factors that get in the way.
More babbling nonsense.
The isogonic lines on a chart take care of all the problems of where
the actual north/south magnetic poles are.
As for constant corrections, the time period for corrections is measured
in years.
Early navigators used it because they had nothing better. Today there are
lots of things that are better.
Wrong again, bucko, there is nothing better for finding north in an
airplane in flight.
The only way to find magnetic north is a magnetic compass.
The only ways to find true north are celestial navigation and a true
gyro compass.
You can't use celestial navigation unless you have a clear sky, an
almanac, a precise clock, and the necessary instruments to measure
celestial angles and the training to be able to use it all.
You can't use a true gyro compass because they can take hours to
settle to a usefull reading, are enormous and heavy, and don't
work unless you are moving very slowly, i.e. at the speed of a
ship. They do not work if moving at airplane speeds and they
don't work without power.
GPS could be used to indirectly find either type of north, but it
doesn't work without power, which is an important concideration
when flying a real airplane without a pause button.
Inertial navigation requires an initial set up against something
else, constant updating measured in minutes, and again, power.
--
Jim Pennino
Remove .spam.sux to reply.