Why The Hell... (random rant)

Are VOR's all MH based?

I was flightplanning the other day (I must be one of the few poor
souls left who flight-plans by hand... I guess I just haven't been
flying long enough to get sick of it yet, I consider my flight
planning to be 'part of the experience') And I got to thinking-

Why in gods name are VOR's Mag heading based?

I know, ideally, that means that you can sync your DG and your VOR
indicator to fly to a waypoint... except that most VOR's around here
have long since fallen behind Magnetic drift... so - now, not only do
you have to flightplan in True Heading, convert to Mag Heading to get
your vectors, THEN you have to get the corrective factor for each of
the VOR's your using for navigation and note that as well? huh?

I'm sorry... call me lazy, but if your not going to keep them all
updated with Magnetic north, then at least stick them on a standard
baseline... True North, for example?

/rantoff.

EridanMan writes:

I'm sorry... call me lazy, but if your not going to keep them all
updated with Magnetic north, then at least stick them on a standard
baseline... True North, for example?

I think aviation should have started moving towards true north for everything
long ago, but that's just me. The constant shifting of the magnetic poles
(which is accelerating) means perpetual updates for anything that depends on
magnetic north (and you can't use magnetic south, because it isn't even
exactly opposite magnetic north).

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In rec.aviation.piloting Mxsmanic wrote:
EridanMan writes:

I'm sorry... call me lazy, but if your not going to keep them all
updated with Magnetic north, then at least stick them on a standard
baseline... True North, for example?

I think aviation should have started moving towards true north for everything
long ago, but that's just me. The constant shifting of the magnetic poles
(which is accelerating) means perpetual updates for anything that depends on
magnetic north (and you can't use magnetic south, because it isn't even
exactly opposite magnetic north).

Where do you get a true north compass?

Your comment about magnetic south being unusable is just asinine.

--
Jim Pennino

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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.

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.

Early navigators used it because they had nothing better. Today there are
lots of things that are better.

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Mxsmanic wrote:

Magnetic south isn't exactly the opposite of magnetic north on the Earth's
surface,

No you are confused. Magnetic SOUTH is the exact opposite of magentic
north you fool. The fact that the MAGNETIC SOUTH POLE is not exactly
opposite the MAGNETIC NORTH POLE is a different issue. The fact that
the poles aren't aligned with the arbitrary "true" datum just means that
the variation equations aren't as simple as they might be. This is why
we just resort to looking it up on a chart.

Early navigators used it because they had nothing better. Today there are
lots of things that are better.

Really, like what? Compasses are still damned reliable compared to
anything else. Cheap too. The only thing that presumes to do better
perhaps is GPS. And it's easier to program that to deal with the
magnetic measurements than to try to force everybody else the other
way.

What I'm not 100% convinced of is the necessity of keeping the VOR's
aligned with your compass. A compass is a perfectly valid
navigational tool with or without VOR alignment, and all of our
aircraft have compass cards in them anyways for coverting between
Magnetic and True headings.

Seems to me using the same conversion factor for Magnetic Heading to
VOR Radial as we do for Magnetic Heading to True is no more
complicated (and in fact less so) then worrying about particular
magnetic offsets for each station?

Either way its pretty much a moot point - because yes - we fly to keep
the needle centered, period. Again then - why go to the expense and
trouble of re-aligning all the VOR's and re-numbering the Victor
airways every few years? Just align everything true-north and don't
touch it again?

Note - this was a semi-inebriated, pedantic rant, I just thought it
might stimulate some good discussion

Ron Natalie writes:

No you are confused. Magnetic SOUTH is the exact opposite of magentic
north you fool. The fact that the MAGNETIC SOUTH POLE is not exactly
opposite the MAGNETIC NORTH POLE is a different issue.

I assumed that others would understand this, but I often get into trouble when
I assume others will understand things.

The fact that
the poles aren't aligned with the arbitrary "true" datum just means that
the variation equations aren't as simple as they might be.

They are more than just misaligned: they are not at opposite points in terms
of longitude and latitude, either. A line drawn between them does not
intersect the center of the Earth.

Really, like what?

GPS and inertial reference platforms, VORs, NDBs, you name it.

Compasses are still damned reliable compared to
anything else. Cheap too. The only thing that presumes to do better
perhaps is GPS. And it's easier to program that to deal with the
magnetic measurements than to try to force everybody else the other
way.

So how often do you fly using just your magnetic compass alone?

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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

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writes:

A sensor to find true north in an airplane in flight doesn't exist.

GPS finds true north. And, just incidentally, you can find true north by
looking at the sky. ANS will do that, and people can do it, too.

The isogonic lines on a chart take care of all the problems of where
the actual north/south magnetic poles are.

Documenting them doesn't really eliminate them.

Wrong again, bucko, there is nothing better for finding north in an
airplane in flight.

GPS is better, and more accurate, to name just one.

The only ways to find true north are celestial navigation and a true
gyro compass.

You can find true north by looking at the sky, or with GPS, or with ANS
(automated looking at the sky), or with an INS. The latter usually has to be
on the ground, although some systems support align-in-motion with a longer
setup time.

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 need a precise clock to do just about any navigation. The need for the
rest is debatable, depending on how resourceful you are.

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.

Unless the airplane is a glider, you have power.

Inertial navigation requires an initial set up against something
else, constant updating measured in minutes, and again, power.

One third correct: it requires power, but engines provide power. It doesn't
have to be set up against anything else to find true north. It doesn't need
to be constantly updated; the whole idea is to be fairly autonomous.

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Mxsmanic wrote:
EridanMan writes:

I'm sorry... call me lazy, but if your not going to keep them all
updated with Magnetic north, then at least stick them on a standard
baseline... True North, for example?

I think aviation should have started moving towards true north for everything
long ago, but that's just me. The constant shifting of the magnetic poles
(which is accelerating) means perpetual updates for anything that depends on
magnetic north (and you can't use magnetic south, because it isn't even
exactly opposite magnetic north).


Because we don't have a TRUE NORTH indicator in the cockit. Just
a magnetic compass and instruments derived from it. Real flying
ain't a stupid-assed computer simulation.