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VOR's are killin me

PostPosted: Sun Jan 15, 2006 8:14 pm
by tennm1980
OK, Im now starting to learn the VOR part of ground school. Does anyone have any tips on how to learn this stuff? It seems tremendously overwhelming. Ive done great up to this point, now I find myself lost. Any info on how you mastered this topic is wonderfully appreciated.

Re: VOR's are killin me

PostPosted: Sun Jan 15, 2006 8:51 pm
by Brett_Henderson
The good news is:  FS9 is a TREMENDOUS tool for learning VORs and VOR navigation..

It's kinda counter-intuitive at first but you'll catch on quick.

Just think of the VOR station as a point that has 360 roads leading straight out. With the OBS knob.. you choose the road (radial) that interests you and the CDI needle tells you were you are relative to that radial. The to/from arrow tells you  that if you were on that radial and flew that heading whether you'd be going to or from the station.

OR...  You can spin the OBS until the CDI centers to find out which radial you're on at that moment.

Check out this link.. it's for "Simulator navigation", but trust me.. it applies to real VOR use too.

http://www.navfltsm.addr.com/index.htm

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 12:13 am
by Mobius
Remember that whatever radial you have dialed in is the heading of the path you would have to fly to be heading straight to or away from the VOR and the CDI needle shows you how far to the left or right of that path you are.

Image

In the first part, you are to the right of the radial you want to be on, in this case the 90

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 1:32 am
by TacitBlue
I couldn't wrap my head around it either untill I got a sectional chart. If you have access to one, then use it to plan a flight with a VOR. For me, it's just one of those things, I don't know why I couldn't understand it before, and I can't explain it now that I do. ;)

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 1:48 am
by BFMF
Don't worry. You will get it. I was once in the same situation. I remember reading VOR and navigation section in the FS5 manual over and over but couldn't seem to grasp the concept. Finally, someone physically showed me how to operate the VOR equipment in FS98, and it clicked.

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 3:32 am
by RitterKreuz
Check your e-mail at hotmail. I have sent you a step by step detailed account of what you are wanting to see and accomplish when using a VOR and the indicators. Everyone who has come to me with this problem has read this "lesson" on paper and done it once in the airplane and never had problems again.

A lot of instructors and a lot of students make this harder than it has to be. It is important to understand VORs as they are the back bone of the airway system. with practice , patience and PROPER GUIDANCE you will get it down expertly.

I hope the e mail helps you out. You might even print it and try it on the flight simulator. if so make sure you are a good 20 miles or so from your favorite VOR. (for the sake of practice.)

I hope it helps you out
Good Luck!

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 5:55 am
by beaky
Can't add much here, except to say that once it clicks in your head, you'll wonder what seemed so complicated about it.
 And the part that seems most complicated on paper-figuring out what airplane heading is needed (to compensate for wind) in order to give you a courseheading that keeps you on a radial-
is, in practice, pretty intuitive.

But  remember the three big rules:
-Tune and ID first (always!!!)
-Make sure OBS is properly set for "to" or "from"
-Don't "chase" the needle

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 9:09 am
by Brett_Henderson
This is where terminology gets tricky. Rotty's right in that chasing needles (especiallly when you're near the VOR .. or .. Flying an  ILS (which is a hyper-sensitive VOR with one radial only (runway heading))) is bad practice and can have you zig-zaging.. But, in reality you do chase the needle.. as in, a right-of-center deflection does not mean that YOU'RE right of course.. it means you need to TURN  to the right of the OBS setting to intercept the course. To what degree you "chase" that needle depends on how far it's deflected. Each dot of deflection represents two degrees. If you've dialed in 090 and are flying TO the station and the CDI is two dots to the right it means that you're on the 094 radial .. and you need to not only turn to the right of 090, but even to the right of 094 (a 094 course at that instant would take you straight to the station on the 094 radial) to intercept the 090 radial.

I'm stealing and modifying Mobius' artwork here (hope you don't mind)...

Image

Note the two dot deflection on the CDI represents a 4 degree radial difference. You can confirm this by turning the OBS to 094 and see that the needle will center.

Flying FROM a VOR.. everything is just mirror imaged..

OK.. now that you're head's exploding go fly the Sim  ;)

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 7:36 pm
by beaky
True, true... but what I meant by "chasing" was to never try to keep turning this way and that until the needle stays put. That doesn't work very well, and when turning you should be referencing your flight instruments, not the navaids.
There's a better way to track it, even if you have no clue, at first , what wind correction you should use:
 Let's say you've got the needle centered, and you've turned to the heading that should put you on the radial, heading straight for the station. The needle drifts away, indicating you've crossed the radial you want, but despite having a compass heading that matches the radial, you're drifting due to wind. The thing to do, rather than banking while watching the needle, is to note your heading, then turn 20 degrees towards the needle. When it flips past the middle again, turn back the other way- but this time only ten degrees. Keep doing this, cutting the angle in half each time, and soon you'll know what heading will keep you on track. And while turning, you're referencing the flight instruments or the horizon, not chasing that silly needle.

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 9:47 pm
by Brett_Henderson
Excellent points.. all this no wind theory is good for forums.. but there's always wind.. especially aloft.. And it's GOOD habits to VOR navigate like it's IFR.. even if you're flying VFR. DO NOT fly by the VOR.. fly your primary instruments or you will end up chasing that needle (probably in circles ..lol..)

Re: VOR's are killin me

PostPosted: Mon Jan 16, 2006 10:00 pm
by Mobius
(probably in circles ..lol..)


I remember from ground school, you actually fly a spiral around the VOR, can't remember why though. :P :-[ ;)

Re: VOR's are killin me

PostPosted: Tue Jan 17, 2006 9:18 am
by Brett_Henderson
I remember from ground school, you actually fly a spiral around the VOR, can't remember why though.


Certain VOR approaches have, as part of their "procedure", depending on which heading you're coming in , something called a DME-ARC. It's where you fly part of a circle at an exact radius from the VOR.. before turning runway heading.

Re: VOR's are killin me

PostPosted: Tue Jan 17, 2006 4:26 pm
by beaky

I remember from ground school, you actually fly a spiral around the VOR, can't remember why though. :P :-[ ;)


Same thing happens when you fly "straight" to an NDB with a crosswind:
you keep turning to keep the needle straight, and you're drifting, so your path becomes an arc rather than a straight line.