Since I live close to King schools, a visit is worthwhile. I think that its a simple stuck on stupid item for me to overcome with regard to VOR and magnetic compass but I know many folks from private going to instrument are challenged as well in this area.
Scott
You may have given a hint as to the problem right there.
There is ZERO relationship between the OBS and headings on a VOR receiver and the DG. None. (More experienced pilots, wait... I'll explain...)
Think of the VOR receiver as a position locator only at first. It tells you only one thing. What direction you are from the station. That's all it knows. (Or TO the station, but let's stick with from only for the explanation.)
When you turn the OBS to a heading, the receiver is going to show your relationship to a line drawn through the location of the station. It is NOT showing you how that relates to what direction your airplane is pointed (the DG).
Let's say you tune the VOR receiver to a frequency and then twist the OBS to a number of 180. The needle centers and the TO flag is visible. This tells you WHERE you are. NOT what direction you're headed.
180 TO is also 360 FROM. You are directly north of the VOR station. It does not matter what heading your airplane is flying, or if you are even pointed straight up or straight down. The OBS is telling you where you are in relation to the VOR station.
So that's the basis of how to APPLY this knowledge. Let's say now the airp,and has moved a bit and we don't know which direction. Just for the mental game.
You've got the OBS still set on 180 TO needle went to the right. This means if you were flying a heading of 180 also, that the radial you are trying to track is now to your right. West of you. Imagine it out there. The beam from the VOR is a laser beam and you can see it.
The more he needle moves to the right, the further away from your airplane that radial is (kinda... Depends on how far you are from the VOR but to get this figured out in your head, let's pretend you're a number of miles from the VOR ground location and that beam is over there like the Death Star laser, just shining straight to the north of the VOR.)
Anyway, you're probably getting the idea here now. That beam from the VOR doesn't move. And the OBS selects which beam you can " see" on the needle.
NOW let's add the DG. You're flying straight east. That needle is swinging to the right because if you were flying south TO the station on that laser beam, you'd have to turn right to get back on it.
Let's turn around from 090 on the DG and fly a heading of 260. Straight west.
What's that needle going to do?
It's going to start moving back toward the center. You're now getting closer to that laser beam you can see out there shining across your flight path. You are now on an "intercept" course. But it's an awfully steep one. Let's keep flying west and see what happens.
Hey! It kept moving to the center of the VOR head and if we look out the left window, there is that white VOR building right off our left wingtip! Okay let's not turn yet. Let's see what the needle does.
Yep. It keeps moving as we fly past the laser beam and leave it behind us. Now it's off to the left and moving further away from the center.
If this is all making sense so far, the rest is application of the two things we know to put ourselves where we want the airplane to be. Let's say we want to TRACK that laser beam and we want our course to be right on the line of that laser beam. A line drawn right straight north of that VOR and we want to go all the way to the VOR and keep going south on that laser beam.
Let's do a right 180 and head back toward the laser beam. Now we know we can't just fly 090 forever because it'll do the exact same thing it did when we flew across it westbound. It'll center up and then keep going behind us as we cross that laser beam. So we need a plan to intercept this thing and then fly along it.
Here's where some knowledge of how far away you are from the VOR is helpful. If you're really close, the needle moved QUICK across that instrument as you flew over the laser. If you're 50 miles away, it took a long time to get back to the laser beam and fly across it and the needle moved slooooooow.
One can find how far away one is via another VOR radial/laser beam, or maybe you have DME, or let's just say you have situational awareness and know you're about ten miles north of that pretty white funny looking building.
Ok. We are headed 090. The OBS still says 180 TO and that's the laser beam we want to fly on. Let's fly back until that needle is about halfway in, and then we'll use a little trick of the geometry of the instrument itself to intercept that darn laser beam.
The needle is now about halfway in and we know we need to start turning right to eventually end up at 180 going south. But if we simply turn to 180, that needle will stop moving because we aren't getting any closer to that laser beam. It's off there to our left and we'll never get there flying straight south. We'll parallel it forever.
So how do we know how much to turn? Here's the trick...
Draw an imaginary line straight up from where the needle is touching a dot or however your VOR head shows the middle line...and read the heading straight above that needle's location. And fly THAT heading.
I bet it says something like 135. And that, if we think about it, is a 45 degree angle to 180. We're ten miles away. So for now, that'll work. We'll be flying south east toward that laser beam but not so steep as to blow by it when we get there.
Let's fly this for a bit. And look. The needle is moving toward the center from the left, because that laser beam is off to our left and we're angling in toward it. See it shining past us out there? (Use that imagination! What color is it? Do you like green or blue lasers?)
Our OBS, the laser beam detector, is noticing we are getting closer. It keeps moving toward the center. We're almost there. Maybe we'll overshoot. Hmm. Let's figure out how to not blow through that line made by the laser beam over there. How can we do that?
Same trick. Note where the needle is and draw a line straight up to the numbers on the top of the OBS. I bet now it says something like 165. Cool. That's a 15 degree intercept and much slower than a 45. Let's fly that now.
The needle slows down a little more and we can see that we are real close to that laser beam and we are getting closer to the VOR station building out there on the horizon. Cool. Eventually the needle centers up and now we need to do something to fly that "180 TO" laser beam. What is it?
Turn right to 180! Now we are "on the beam"! Sweet. If there's no winds aloft, our DG is set perfectly to the mag compass, we fly 180 and that needle stays right there in the center. That laser beam from the VOR is blinding us through the windshield.
Eventually we get to the VOR and cross over it. The OBS gets a little confused when we are right overhead and the TO flag disappears. It can't see the laser beam!
You keep flying that 180 heading. The OBS can see the laser and its behind us shining on the tail! The flag flips. It says "180 FROM" now. And we keep flying south on our merry ground track.
Now with wind, this changes a bit, since you might be being blown toward or away from that laser beam.
The point of this mental exercise is to get you thinking about the VOR radial, or as I've called it for helping get the imaginary point across, a "laser beam" coming out of the VOR building, having absolutely nothing to do with your airplane's heading on the DG (or your magnetic compass which is what you set that DG from).
It's telling you where you are located from a "line of position" that's created by a radio " beam" (ahhh... WeirdJim won't like that description because that's not how the actual VOR signal works, but bear with me for the analogy!) that comes out of the station.
Once you get over the stumbling block that the OBS head and the DG look similar, (so they must do similar things, right? No!) and realize the OBS is a "beam finder", the rest can fall into place. Think of it as a really weird GPS that only knows how to find lines that radiate from that VOR station the frequency is tuned to.
Learn to read it as "the radial I would need to fly a heading of 180 TO the station would be off to my left/right if I were actually flying that heading"... Then imagine where on the map that "laser beam" would be, and only THEN think about the next part... Which way would my airplane need to fly to get to that laser beam?
Once this clicks, then you can start to play games like overlaying the needle mentally over the DG, which... Is exactly what an HSI does mechanically.
So maybe, if I caught the hint correctly in your post, I think you're trying to mash all those steps together into one before doing them separately. Don't worry about the DG at first. Use the VOR OBS first separately to find where you are from that laser beam.
If you're ever REALLY lost or confused, just spin that OBS until it centers up on a FROM flag, and draw a line on that heading FROM the ground location of the VOR outward. You are ON that line. You don't know how close you are, but you're definitely on that line. If it centers up on say, 260 FROM, you are directly west of that VOR and the OBS "sees" that laser beam.
NOW figure out if that's where you want the airplane to be, and which way to turn to go where you want to go. That the SECOND step. Not the first. The first is knowing where the airplane is from that laser beam.
That help?
Think of that OBS as an old school laser beam detector!
