Post by LOU on Mar 15th, 2011 at 2:52am
A quick look at VOR navigation.
The VOR is a very handy tool to find your way around the sky.
Try to visualize a lighthouse with a beam that spins at 1 RPM. Every time the light beam passes magnetic north there is a bright flash of light to tell you that it is pointing at north. As you look at the lighthouse and see the bright flash you start a stop watch. When the rotating beam of light points to you, observe the stop watch. For this example let's say you see the beam go by you at 15 seconds. You are at 90 degrees from north at 15 seconds, or another way of saying this would be that you are on the 090 degree radial from the lighthouse station.
To go to the lighthouse you would need to track the 15 second (090 degree radial.) If you start to see the watch showing 17 or 18 seconds as the beam passed your position you would be drifting left of course. Does this make sense? If it does, you are starting to visualize how the VOR works.
Here are some things you need to keep in mind...
1. RADIALS radiate from the station.
2. You cannot fly into a radial! :-?
When you fly using the VOR the OBS and the Compass must be almost the same.
In the example of the lighthouse, above, you are on the 15 second radial which we need to change to degrees so you can use this example and apply it to VOR's. In order to fly TO the lighthouse (VOR) your OBS selection and compass must agree. So the OBS would be set to 270 degrees and now you can fly TO the VOR with to-the-needle sensing. Remember - RADIALS radiate FROM the station. You cannot fly into the station - backwards - on that 090 degree radial because the display on your instrument will be reversed. So, you must dial in the reciprocating or opposite radial so you will get proper needle display. To fly backwards on the radial is called dragging the needle.
Now if I have not made you completely lost here is a look at a typical trip using some VOR's.
The VOR's for this trip are named A, B, C & D. Our trip starts at an airport called Mark's Farm (MARKOZ) not far from VOR-A. We are the GREEN plane. To get to the VOR is easy. Just tune and identify the VOR station. Turn the OBS until the needle centers with a TO indication. The number in the OBS will show you the RECIPROCATING radial, the one on the other side of the VOR. Now, if you just fly that heading you will fly to the station. As you fly, you will need to correct for wind drift. If the plane drifts left of course the needle will move to the right showing you where the selected course is. Make a small correction for the wind. As you near the station the needle will get sensitive and move around quickly. Don't chase the needle, just fly your heading. When you cross the station you will be in the cone of confusion. To fly outbound from station A you will need to fly the 110 degree radial. Dial the OBS so it reads 110 and turn to that heading. If you know the wind already, you can apply a correction to your heading, or just see what the needle says. As you passed over the station, the TO/FROM indicator flipped to FROM showing station passage.
You can follow the trip using the colored planes to see the display in the VOR indicators on the right side of the drawing. I put in the purple plane to show that flying the wrong way will give you the opposite needle indication. If you flip the purple plane to the inbound course, the indicator is correct.
The intersections of HEAVY and LIGHT are made from the radials of VOR D or by the DME from the noted VOR's.
I hope this helps you to understand how to go from VOR to VOR.
Lou
The VOR is a very handy tool to find your way around the sky.
Try to visualize a lighthouse with a beam that spins at 1 RPM. Every time the light beam passes magnetic north there is a bright flash of light to tell you that it is pointing at north. As you look at the lighthouse and see the bright flash you start a stop watch. When the rotating beam of light points to you, observe the stop watch. For this example let's say you see the beam go by you at 15 seconds. You are at 90 degrees from north at 15 seconds, or another way of saying this would be that you are on the 090 degree radial from the lighthouse station.
To go to the lighthouse you would need to track the 15 second (090 degree radial.) If you start to see the watch showing 17 or 18 seconds as the beam passed your position you would be drifting left of course. Does this make sense? If it does, you are starting to visualize how the VOR works.
Here are some things you need to keep in mind...
1. RADIALS radiate from the station.
2. You cannot fly into a radial! :-?
When you fly using the VOR the OBS and the Compass must be almost the same.
In the example of the lighthouse, above, you are on the 15 second radial which we need to change to degrees so you can use this example and apply it to VOR's. In order to fly TO the lighthouse (VOR) your OBS selection and compass must agree. So the OBS would be set to 270 degrees and now you can fly TO the VOR with to-the-needle sensing. Remember - RADIALS radiate FROM the station. You cannot fly into the station - backwards - on that 090 degree radial because the display on your instrument will be reversed. So, you must dial in the reciprocating or opposite radial so you will get proper needle display. To fly backwards on the radial is called dragging the needle.
Now if I have not made you completely lost here is a look at a typical trip using some VOR's.
The VOR's for this trip are named A, B, C & D. Our trip starts at an airport called Mark's Farm (MARKOZ) not far from VOR-A. We are the GREEN plane. To get to the VOR is easy. Just tune and identify the VOR station. Turn the OBS until the needle centers with a TO indication. The number in the OBS will show you the RECIPROCATING radial, the one on the other side of the VOR. Now, if you just fly that heading you will fly to the station. As you fly, you will need to correct for wind drift. If the plane drifts left of course the needle will move to the right showing you where the selected course is. Make a small correction for the wind. As you near the station the needle will get sensitive and move around quickly. Don't chase the needle, just fly your heading. When you cross the station you will be in the cone of confusion. To fly outbound from station A you will need to fly the 110 degree radial. Dial the OBS so it reads 110 and turn to that heading. If you know the wind already, you can apply a correction to your heading, or just see what the needle says. As you passed over the station, the TO/FROM indicator flipped to FROM showing station passage.
You can follow the trip using the colored planes to see the display in the VOR indicators on the right side of the drawing. I put in the purple plane to show that flying the wrong way will give you the opposite needle indication. If you flip the purple plane to the inbound course, the indicator is correct.
The intersections of HEAVY and LIGHT are made from the radials of VOR D or by the DME from the noted VOR's.
I hope this helps you to understand how to go from VOR to VOR.
Lou