Wind at aircraft 180 deg off phase from value set with 2DE0

[bernsa]

Pete,

We've been doing some experimentation to determine the effects of winds on flights and I wrote my own application to replay wind variability using principally the 2DE0 and 2DE8 offsets in FS2004. We are on 3.48 of FSUIPC.

We first noticed something odd when after analyzing data from our test runs that flights we set up with tail winds were slower than flights set up with head winds which were faster than our no wind baseline flights... basically the opposite effect of what we were expecting.

This morning after concluding a test flight, I had noticed that with weather that was inputted as 050/5 was showing 3 kt IAS while stopped at the ground and the aircraft on a heading of 272 at KATL. This looked odd to me, so I rotated the plane to point to a heading of 050 and the IAS read 0. Rotating to a heading of 230, the IAS read 4 kt IAS. I double checked the values for 2DE0/2DE8 in my software, FS Interrogator and both confirmed a heading of 050/5. Additionally SHIFT+Z information reads as winds 050/5 and during flight the winds read as 050/5 on the aircraft NFD. It appears to me that even though the weather was entered correctly, and the sim displays it correctly as 050/5 it seems to be implemented at the aircraft as 230/5 which could explain why our head wind flights were faster than tail wind flights.

We have repeated this on 3 different installations and all have the same effect.

Can you shed some light on this or let us know if there is something we could be doing wrong?

[Pete Dowson]

I wrote my own application to replay wind variability using principally the 2DE0 and 2DE8 offsets in FS2004. We are on 3.48 of FSUIPC.

...

It appears to me that even though the weather was entered correctly, and the sim displays it correctly as 050/5 it seems to be implemented at the aircraft as 230/5 which could explain why our head wind flights were faster than tail wind flights.

...

Can you shed some light on this or let us know if there is something we could be doing wrong?

I don't know. I don't think anyone else has ever used those facilities. I thought they were okay, but I have no programs which use them so a thorough test hasn't been possible. If you have a small program which I can use to test it, I'll trace through the code. Possibly the direction in the variable I'm setting is the "to" direction not the "From" for some reason.

If so, I'll fix it in the forthcoming version 3.50.

Regards,

Pete