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[NOBUG] Wind direction in VIND/RUTA/MAL does not agree with course ring & HUD


Leviathan667

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Wind direction in VIND/RUTA/MAL does not agree with course ring & HUD

 

According to the manual, switching the data selector to VIND/RUTA/MAL will show:

 

the wind used for the navigation calculations. The data indictor’s first three digits dipslayed is the wind direction. The fourth and fifth digits display the wind speed.

 

If the Doppler wind is displayed, the last digit is a zero (0). If the forecast wind is used the

last digit is a minus sign (-).

 

If the waypoint button LS SKU is pressed, the forecast wind (if entered) is displayed.

 

RC 2 Manual, p. 193

 

But, in the game, it seems VIND/RUTA/MAL show not the wind direction but the opposite (wind direction + or - 180°). On the attached screenshot, the wind direction is, according to VIND/RUTA/MAL, 232° at 43 km/h.

 

Since the plane’s heading is roughly 136°, then the wind is pushing the plane to the right.

 

BUT

 

On the HUD, the steering command to waypoint B1 is veering to the left meaning the aircraft’s nose is pointed slightly to the right of its flight path. My understanding is this happens because the wind is pushing the plane to the left. The wind’s real direction seems to be 52°, not 232°.

 

Further confirmation comes with the fact the course ring shows that the nose of the plane is heading towards 136° whereas the waypoint direction is slightly to the left, at 132°. Still, the FPM shows the aircraft is actually heading towards the B1 waypoint. In other words, to fly towards the waypoint, the plane’s nose has to be pointed slightly to the right of its desired flight path. This also suggests the wind’s real direction is 52°, not 232°.

 

The same line of reasoning is also supported by the steering command on the ADI.

 

 

So I am either wrong and would like to know what is the correct understanding of these readings or the manual is wrong and VIND/RUTA/MAL is not supposed to show the wind direction or the information displayed in VIND/RUTA/MAL is wrong and should be corrected to show the actual wind direction.

Screen_191028_212106.thumb.png.4b8cea57ae0775194f9428aaf9437735.png


Edited by Leviathan667

Wishlist: Tornado ADV/IDS, Blackburn Buccaneer, Super Mystère B2, Saab J 35 Draken,

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Wind direction is defined to be direction looking into the wind. So, a 232d wind is blowing from southwest to northeast, which seems to be in accordance with your findings here, i.e. blowing the plane going southeast to the left.

 

Anyway, why don't you just define the wind in the mission editor so you know the direction? Just be aware that (if I recall correctly) for some reason the mission editor defines wind direction in the opposite direction, so a 232d wind would in fact show up as 52d in the editor.

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Agreed, wind correction is backwards in Viggen. @alftand is correct, however, about how wind is displayed in VIND/RUTA/MAL. Specifying the direction the wind comes from is how it is done in weather forecasts, which makes it natural to represent winds the same way in the aircraft.

 

I set up a practice mission with a strong wind from west to east, and Viggen correctly displayed the wind direction as 270°. The steering command in the HUD also seemed to be working as it should. When heading south, I would see very similar symbology to what is shown in OP's screenshot. The nose would have to point a few degrees into the wind (to the right for both OP and me) for the airplane to hit the waypoint.

 

I also experimented a bit with bombs and BK90's in the same weather setup. Bombs in PLAN mode (both with and without chutes) and BK90's all fail to hit the target unless I manually enter a wind direction 180° offset from the actual direction (in my case 90° instead of 270°). Unless manually entering the opposite wind direction like that, the HUD symbology in PLAN bombing mode directs you to drop the bombs on the wrong side of the target seen from the wind. In my case the steering order directs me to the east (left) side of the target.

 

Even when entering the opposite wind direction, I found that the bombs would not quite hit the target spot on, but if I also doubled the wind speed they would hit a lot more accurately. Same thing with the BK90's. Not sure those results are very relevant though, since I was flying in silly hard winds (12 m/s).

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Thank you all for your comments. I guess I was mistaken when I thought wind direction meant where the wind was going to as it actually is where the wind comes from.

 

Also I read a few forum posts where people report the wind direction in the mission editor is wrong because it shows where the wind comes from insteading of where it is headed. This too is fueling my confusion.

 

On a similar matter, the ATC does not always seem to properly take the wind into account. For example, in a custom made mission, at Senaki, there's a 348° wind according to the mission editor (coming from 348, heading towards 148) but ATC still has planes take off from runway 09 (94°) instead of runway 27 (274°). The idea here is to take off towards the wind as much as it is possible.

 

So I thought we should want the difference, in absolute value, between our heading on the runway and the wind to be as close a 180° as possible. E.g.:

 

|094-148| =54

|274 - 148| = 126

 

Am I in the wrong here? What do you think?

Wishlist: Tornado ADV/IDS, Blackburn Buccaneer, Super Mystère B2, Saab J 35 Draken,

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The wind direction in the mission editor is the other way around, which may very well be the origin of much of our confusion. It shows the direction where the wind is heading. There is a small arrow indicating the wind direction and if you input 90° in the ME, the arrow will point to the east. The CK37 in Viggen will then be indicating a wind direction of 270°.

 

You should be able to verify in the ME if the arrow points towards the north (and 12° west) for your custom made mission. The indicated wind in CK37 should then be close to 168°. If so, the ATC would be right in sending off planes on rwy 09. Any wind direction between 4° and 184° should be OK for rwy 09.

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