MSFS20 Ambient Wind Direction

[ark1320]

Is the Avar Ambient Wind Direction a true or magnetic value in MSFS?
Thx,
Al

 

[B21-soaring]

... not that easy to work it out in the sim.

I think the definitive method would be to see if AMBIENT WIND X reads 0 with AMBIENT WIND DIRECTION set to 0.

Alternatively park next to a windsock somewhere where there's a big magnetic deviation and point the aircraft in the same direction as the windsock, and compare PLANE HEADING DEGREES MAGNETIC and AMBIENT WIND DIRECTION

 

[ark1320]

... not that easy to work it out in the sim.

I think the definitive method would be to see if AMBIENT WIND X reads 0 with AMBIENT WIND DIRECTION set to 0.

Alternatively park next to a windsock somewhere where there's a big magnetic deviation and point the aircraft in the same direction as the windsock, and compare PLANE HEADING DEGREES MAGNETIC and AMBIENT WIND DIRECTION

I've been told that someone from Asobo reported Ambient Wind Direction is a TRUE value. I seem to recall that is also the case in P3d/FSX.
Thanks for the reply,
Al

 

[B21-soaring]

After testing, AMBIENT WIND DIRECTION is definitely DEGREES TRUE. Kinda makes sense if the main use is to animate a windsock.

I took a break from what I was supposed to be doing and parked the FA-18 at BGSF in Greenland (27 degrees magnetic deviation)- runway 27 (= magnetic 242, true: 269) .

So on loading the plane onto the runway:

PLANE HEADING DEGREES TRUE: 242
PLANE HEADING DEGREES MAGNETIC: 269

Setting AMBIENT WIND DIRECTION to 242 and looking at the windsock (which I'm damn sure will be animated with AMBIENT WIND DIRECTION) it lined up with the runway and the plane, i.e. 242 True.

Also for AMBIENT WIND X to be 0, the AMBIENT WIND DIRECTION has to be 0 or 180.

I actually checked a few other things like what happened to RELATIVE WIND VELOCITY BODY Y with the wind at 242 and flying the plane heading 242 TRUE and basically each thing confirmed the wind direction was in Degrees True (and implicitly confirmed the windsock was animated with AMBIENT WIND DIRECTION).

 

[ark1320]

After testing, AMBIENT WIND DIRECTION is definitely DEGREES TRUE. Kinda makes sense if the main use is to animate a windsock.

Thanks very much for you work on this, much appreciated! You have confirmed my P3D recollection and the input I was told about from Asobo.
Al

 

[B21-soaring]

As a late but significant addendum to this, it should be noted that AMBIENT WIND VELOCITY in MSFS isn't in practice what most people are used to from FSX. I.e. I suspect much programming (including windsocks?) takes AMBIENT WIND DIRECTION as the direction, and AMBIENT WIND VELOCITY as the speed, e.g. for a windsock rotation and horizontal pivot. But in MSFS the AMBIENT WIND Y (i.e. the vertical component of the wind) can be higher than the prevailing wind speed and AMBIENT WIND VELOCITY includes this. An additional twist (pun intended) is the simulation of AMBIENT WIND Y actually has AMBIENT WIND VELOCITY as a very significant parameter controlling its magnitude (go figure) so AMBIENT WIND Y has a very non-linear strength profile. The end result is AMBIENT WIND VELOCITY can sometimes be dominated by the current local vertical wind.

The more mainstream horizontal 'ambient wind speed' can be calculated as square_root(wind_x_squared + wind_z_squared) and FWIW I've suggested Asobo create a new simvar AMBIENT WIND SPEED containing that value.

Given the prevalence of windsocks all over the sim pointing in random directions, it's about time Asobo tidied this up anyway.