Different wind indicated..

[flying_pilot]

Hi Pete!

Look at these picture:

Which one is correct! as a note, I experience the different when flying with the PMDG 737 too. Thanks.

ps. Sorry for the big image, I don't know how to resize.

[Pete Dowson]

Look at these picture:

Sorry, the pics don't seem to arrive.

Which one is correct! as a note, I experience the different when flying with the PMDG 737 too. Thanks.

What's the problem? Rather than pictures, wouldn't it be easier to describe it in words. Some folks say pictures can tell more, but I don't think that is always the case :)

Pete

[flying_pilot]

My apologise Pete for unshown picture. Anyhow, I'll explain in some words.

My PSSA340 was doing test flight, and cruising at FL 310 from KSFO to KLAX. If I press shift+Z the indicated wind was "287/25 Mag", but shown on ND was "302/24", even I think the difference is not significant, but it make me curious.

As previous post, this happen to PMDG 737 too, different wind speed and direction as shown on ND and by using "shift+Z"

Sorry, I can't express much better than an image attachment :lol: , but I did. Thanks Pete.

[Pete Dowson]

My PSSA340 was doing test flight, and cruising at FL 310 from KSFO to KLAX. If I press shift+Z the indicated wind was "287/25 Mag", but shown on ND was "302/24", even I think the difference is not significant, but it make me curious.

As previous post, this happen to PMDG 737 too, different wind speed and direction as shown on ND and by using "shift+Z"

Sounds like it could be one of two things.

1) The ND implementation is wrong, in that it is showing the direction in degrees TRUE, not MAGNETIC. Assuming you are using FS2004 the Shift+Z display shows the wind in degrees magnetic -- this is different from FS2002 and before where it was shown TRUE.

If the difference in direction is the same as the local Mag Var, then that's your answer, and warrants a bug report to the panel makers.

The difference in wind speed will be just a rounding thing. One is rounding off the other up.

OR

2) The gauge code is actually getting the wrong wind data. I think this is unlikely, but it is possible and would certainly be indicated if the difference in direction was not pretty close to the Mag Var all the time.

I should add that neither of these phenomena are related to anything FSUIPC can do. Those panels will be dealing direct with the relevant internals of FS, normally via PANELS.DLL.

BTW, it may be that the lack of mag var correction in the ND's is because, in FS2002 and before, the same programmers wanted to make the ND show the same as the Shift+Z display. This would have been wrong, because if the ND is showing MAG directions (track or heading), the wind arrow should, of course, also be Mag -- but maybe when it didn't show the same as Shift+Z folks complained and the programmers gave in!

As an aside, I see that FSNav is still showing the wind direction in degrees TRUE as well.

Regards,

Pete

[flying_pilot]

Even I'm not quite understand but thanks for the long reply Pete. So there is a problem, now I know.. Regards.

ps. Yes the sim is fs9 and running on WinXp pro with fsuipc 3.08.

[Pete Dowson]

Even I'm not quite understand but thanks for the long reply Pete. So there is a problem, now I know

I don't think there's necessarily a "problem", as such. The difference in wind direction, from the example you gave, does look likely to be the Mag Var (magnetic variation -- the difference between TRUE north and MAGNETIC North, which varies from place to place). I suspect that the panel makers are showing the wrong one, but it is correct in its own way, just incorrect on the cockpit if the ND is set for Magnetic indications -- which it would normally be.

Certainly, you should report this to the panel makers. Such errors were quire prevalent throughout the life of FS2000 and FS2002 too -- I think some were deliberate so that the value shown was the same as the Shift+Z value, but they were errors nonetheless.

Regards,

Pete