I think the main thing that confuses people about VORs is
differentiating between location and course guidance. So let's
remove the couse guidance aspect for a moment:

Imagine you are in a helicopter in a stationary hover pointed
at 360 magnetic. You tune in a VOR and set the OBS to 360. The needle
deflects full left. What does this mean? It means that the imaginary
line starting a the VOR and radiating out (hence "radial") toward the
magentic north pole is located somewhere to your left. Now you do a
180-degree pedal turn so your helicopter is pointed at 180 degrees.
What will happen to the CDI needle? Nothing, because you are stationary.
It will still be deflected full left. However, because you have turned
180 degrees, the radial is now actually to your right. THAT is reverse
sensing.

Another way to think of it is the CDI needle tells you which
direction you need to turn the OBS in order to center the needle.

So now you push the cyclic forward and start your helicopter moving.
You now want to use your CDI for course guidance. If your current
heading is within +/- 90 degrees of your OBS setting, the CDI needle
will be a "command instrument", i.e. it will tell you which direction
to turn in order to intercept the selected radial. If your current
heading is MORE than +/- 90 degrees from your current OBS setting,
then you must turn in the opposite direction of the needle to intercept.

So what about the TO/FROM flag? Your OBS is still set to 360. Now
draw a line perpendicular to 360 passing through the VOR. The TO/FROM
flag can tell you on which side of this perpendicular line you are
located. Like the OBS setting, the TO/FROM flag is NOT related to
what direction your aircraft is pointed. If the flag is indicating
FROM, then you are on the same side of the perpendicular line as the
360 radial. An indication of TO means you are on the opposite side
of the line.


Happy landings,
Ross Oliver