Using VOR only: how do you figure out the radial?

  • I've been flying with VOR only a few times again towards airports that don't have a VOR of their own and I notice that the radials I 'calculate' using the navigation planner (which is a bit complicated to get done) often aren't correct. During my last flight it was way off and I missed the airport by a few nm's. I know VOR's aren't THAT precise but in P3D I usually got better results. I also checked the nearby nav aids on AirNav but the real world radials also don't seem to always work.


    Are there other's here who fly using VOR only? If so, how do you figure out the correct radials to fly on?

  • I'm not sure to understand the question, since the OBS needle shows you where you are compared to the radial inbound or outbound that you have selected on the ring. So, basically, if you're flying on the radial towards your destination AD, you cannot be way off.


    A common mistake however is to mix up magnetic and true north. Your map uses true north, but the VOR radials are relative to magnetic north, (actually, your aircraft is flying relative to compass north, but I don't think this is featured in AFS2).

    Keep in Mind : M = T- VAR, with VAR W <0 and VAR E >0

    VAR in Switzerland is usually some 1-2° and may be neglected, but VAR of 15° is not uncommon in Canada or US, this cannot be neglected...


    Cheers

    Antoine

    Config : i7 6900K - 20MB currently set at 4.00GHz, Cooling Noctua NH-U14S, Motherboard ASUS Rampage V Extreme U3.1, RAM HyperX Savage Black Edition 16GB DDR4 3000 MHz, Graphic Card Gigabyte GeForce GTX 1080 8GB, Power supply Corsair RM Series 850W, Windows 10 64 bit.

    Edited once, last by Trespassers ().

  • I'm not sure to understand the question, since the OBS needle shows you where you are compared to the radial inbound or outbound that you have selected on the ring. So, basically, if you're flying on the radial towards your destination AD, you cannot be way off.

    What I like to do is fly towards an airport that doesn't have a VOR using VORs further away. So I might have to fly on radial 240 from one VOR until I am at for instance 34 nm at which time I should arrive at my destination. I might use another VOR for triangulation, like I should be at radial 34 at 24 nm of that VOR when I arrive. Flying to or from a VOR is dead easy of course: the fun is using those VORs to get somewhere else.


    Anyway, you are probably correct that you can't figure out the radials simply by plotting a course on the navigation map and looking at the headings. However, when I use real world data from AirNav it also doesn't seem to work. Not always anyway. So I am curious to find out how I can figure out the radials I should use in AFS2 to get where I want to get.

  • Anyway, you are probably correct that you can't figure out the radials simply by plotting a course on the navigation map and looking at the headings. However, when I use real world data from AirNav it also doesn't seem to work. Not always anyway. So I am curious to find out how I can figure out the radials I should use in AFS2 to get where I want to get.

    No, you can do it provided that you use the VOR rose plotted on the map, which is oriented relative to magnetic.

    In AirNavPro, please make sure in your settings that you display the magnetic course.


    Cheers

    Antoine

    Config : i7 6900K - 20MB currently set at 4.00GHz, Cooling Noctua NH-U14S, Motherboard ASUS Rampage V Extreme U3.1, RAM HyperX Savage Black Edition 16GB DDR4 3000 MHz, Graphic Card Gigabyte GeForce GTX 1080 8GB, Power supply Corsair RM Series 850W, Windows 10 64 bit.

  • Sorry to disagree, the VOR radials are based on the last survey and recalibration of the station which might have been done many years previously. Look up SkyVector and you can see nearby VORs where the track between them gives radials which are several degrees off a simple reciprocal e.g. not 360 and 180.

    The VOR must be used with the printed north extended arrow symbol, not using a track plotted against true north from a nearby meridian and corrected for local magnetic variation or using an electronic direct plot such as with SkyVector or the Aerofly navigation feature.

    If you use an aviation chart the track must be plotted off the printed VOR symbol magnetic north arrow.


    A very long flight can take you into an area with a different magnetic variation so two perfectly calibrated VORs can show non reciprocal radials.


    Published routes with radials give the proper bearings for the VOR in use.


    This example from the New York area shows a massive 2 degree difference over only 44 miles. The expected pairs would have been 235/055 and 053/233. This format is typical of a radio nav chart or a SID or STAR plate. An approximate radial can be read off the VOR compass rose, Deer Park outbound here looks between 050 and 060 degrees.



    The headings that you find in our aircraft are all magnetic and account for the 15 degree difference between true and magnetic north.

    Correct in the SFO area, magnetic variation is zero in part of Switzerland. The VOR symbol north arrows there point straight up. Aerofly local variation is correct world wide.



  • Ah my backyard :)

    You must be from the NY area. With the exception of Gabreski, I've flown from Republic to every airport on that area of the sectional, several times IRL. Got my Tailwheel endorsement at Brookhaven. Learning VOR navigation and triangulation was fun when I was in flight school (before GPS). I never really cared for the NDB.

    Redtail

    KFRG, KTEB, KEWR, KLGA

    ~Straighten up and fly right~


    DESKTOP: i7-7700k @5GHz (water cooled), Nvidia GTX 1080Ti FTW3, 32GB DDR4, 500GB SSD, Oculus Rift CV1, Windows 10 Home 64 bit,

    TM HOTAS Warthog (large spring removed), Saitek PRO Flight Combat Rudder Pedals, YOKO yoke!

    Laptop (gaming): Acer Predator Helios 500- Intel Core i7-8750H @4.1GHz, Nvidia GTX 1070, 32GB DDR4, 256GB SSD/1TB HDD.

    Gametrix JetSeat FSE (Flight Sim Edition)-USB Vibrating pad. Nextlevel V3 Motion Platform / Sim cockpit.

  • Ah my backyard :)

    You must be from the NY area. With the exception of Gabreski, I've flown from Republic to every airport on that area of the sectional, several times IRL. Got my Tailwheel endorsement at Brookhaven. Learning VOR navigation and triangulation was fun when I was in flight school (before GPS). I never really cared for the NDB.

    There will always be a residual core of VOR and ILS stations kept on to keep the system working in the event of a satnav outage. Big plane inertial reference systems are not precise enough with error increasing over time. It’s prudent to use all the navaids available in a plane, just to be sure.

    I never flew in the U.S., used a SkyVector NYC chart in a search for convenient funny VORs. Here is a VOR listing example from the UK Airpilot. Look at how far out Jersey VOR had got before its update. The magnetic north pole movement has increased greatly so out of date VOR variation will become a bigger effect.




    One way to get accurate sim VOR navigation is to look up the published VOR variation and compare it the local sim variation, presuming that the sim database is up to date. Another way is to plot a long track over the VOR north arrow in SkyVector and observe any difference from local magnetic north. Real world protractors are used over the VORs in paper charts. Estimating the plotted radial using the VOR compass rose in SkyVector is probably good enough. Published fixed routes work fine.

  • Er... okay, very interesting ;) but I still don't have a clue how to figure out which radials to use whenever I want to fly somewhere using VORs. The AFS2 Nav page doesn't have a VOR rose so I don't know what to do with a VOR rose. When I read Jan's post it seems though as if the headings in AFS SHOULD actually show the correct radials but... why don't those radials get me exactly where I want to get? I will do some more tests...


    EDIT

    Gave it another try and this time it worked out pretty well. I suppose it also has to done with the distance to the VOR: how further away you are the larger the possibility of missing the airport may be (because obviously the distance between radials gets bigger at larger distances). It also helps to fly to an airport which doesn't lie hiddden in the mountains LOL


    Here is how I figure out the radials (which in this case equals the headings) to fly (doing a rather simple straightforward flight):


    I want to fly from Los Banos Municipal to New Coalinga. I pick the PXN VOR to fly from towards the airport. In order to figure out the exact heading I have to set another random airport as destination (in this case Delano) otherwise the automatically added FAF gets in the way. (Bless the day we will get an improved planner!) I have to add a user waypoint manually as close as possible to the destination because you can't add another airport to the plan as a waypoint. (Again, bless the day...)

    This screenshot shows the heading from PXN to New Coalinga is 131 and the distance 40.4 NM. So if I fly that 'radial' I should arrive at New Coalinga when I am at a distance of 40.4 NM.



    As a crosscheck I also figure out the 'radial' from the ROM VOR. Again, the actual destination is New Coalinga, not Delano,

    This screenshot shows the heading from ROM to New Coalinga is 71 and the distance 17.8 NM. It is a bit cumbersome having to do it this way but well, it works.



    Here is the final result. The PXN 131 radial (VOR1) got me to the airport pretty accurately. The ROM radial is set to 71 (VOR2) and the needle is still fully deflected but as you can see on the next screenshot...



    ... both needles are more or less centered after landing. So this worked out pretty fine. The PXN radials may have been off by one degree but that's not much. Distance was spot on. Don't know exactly what went wrong the previous times...



    Anyway, flying this way is a lot of fun! It keeps you busy all the time and adds a nice challenge. Finding your destination this way is very satisfying! This was a rather simple example flight, I could simply fly towards the PXN VOR after take off and then fly the outbound 131 radial, but things get even more fun and interesting when the VORs are situated elsewhere and you never actually fly over one, like when both VORs are on the opposite side of your destination airport (and you have to use reciprocals) or too far away so you have to intercept radials from a distance. The above flight would have been more fun already if I had taken off from William Robert Johnston in which case I would have to intercept the 131 radial somewhere in between the VOR and the destination. Big fun!

  • Keep the needle centered, correcting for wind and you WILL get there .^^


    Admittedly, I haven't messed with the planner much since getting into FS2 (most of the time I'm just boring holes in the sky in VR enjoying the views), so I was unaware of the fact that it doesn't have roses.

    A VOR compass rose is such an essential part of flight planning, I'm surprised it's hasn't been implemented yet.



    I agree with you, it is a lot of fun. DME and cross checking with second VOR. When I started flying the G1000, I still tune the VORs and cross check. Just remember to keep your head on a swivel for traffic, especially in the NY area8|.

    Although I'm talking real world, I'm sure we will have some awesome AI traffic in the AFS2 future! ;)

    Redtail

    KFRG, KTEB, KEWR, KLGA

    ~Straighten up and fly right~


    DESKTOP: i7-7700k @5GHz (water cooled), Nvidia GTX 1080Ti FTW3, 32GB DDR4, 500GB SSD, Oculus Rift CV1, Windows 10 Home 64 bit,

    TM HOTAS Warthog (large spring removed), Saitek PRO Flight Combat Rudder Pedals, YOKO yoke!

    Laptop (gaming): Acer Predator Helios 500- Intel Core i7-8750H @4.1GHz, Nvidia GTX 1070, 32GB DDR4, 256GB SSD/1TB HDD.

    Gametrix JetSeat FSE (Flight Sim Edition)-USB Vibrating pad. Nextlevel V3 Motion Platform / Sim cockpit.

    Edited once, last by Redtail ().

  • If you wish to add some realism to VOR usage in AeroflyFS2, the speed and damping of OBS deviation needle should be dramatically reduced.


    Here are for instance the parameters I set for the DR400:



    Just like in other simulators, these needles are by default way too responsive in AeroflyFS2. But this can be easily corrected.


    Cheers

    Antoine

    Config : i7 6900K - 20MB currently set at 4.00GHz, Cooling Noctua NH-U14S, Motherboard ASUS Rampage V Extreme U3.1, RAM HyperX Savage Black Edition 16GB DDR4 3000 MHz, Graphic Card Gigabyte GeForce GTX 1080 8GB, Power supply Corsair RM Series 850W, Windows 10 64 bit.