Weather vs. Autopilot

[shackleton_boy 0]

Hi all,I hope you guys can help me. I do most of my FSx flying in the PMDG737 but lately i have noticed a strange issue. When I fly i always use Real Weather (REX) and at random the aircraft starts to bank - either left or right - the bank angle aural warning sounds and the aircraft just keeps on going into a steeper bank. The aircraft would then over correct to the other side and this back and fourth turning would continue until the aircraft stalls and nose dives.The only way to correct it is to clear the weather or fly by hand.Any ideas?

[W1ll 0]

This is a known problem with realistic autopilots called 'S-turning'. As stated in the NGX introduction you have to turn off wind and thermal effects on the aircraft in FSX options. If you use ASE there is a thread here somewhere detailing how it is possible to keep it turned on on with the NGX with no S-turning.

[shackleton_boy 0]

Ok - i'll go change some settings and report back. Surely a real FMC coupled autopilot wont allow the aircraft to go into a 80deg bank and slide?!

[W1ll 0]

It is unfortunately an FSX limitation

[martin-w 3,235]

If you are using REX, I would advise you pay for the registered version of FSUIPC. Then you can set the wind smoothing feature, which will prevent sudden wind shifts.You will also then be able to suppress turbulence, it's turbulence that causes the S-Turn issue.I wouldn't fly without a registered version of FSUIPC, well worth the small investment.My NGX functions perfectly with REX weather and FSUIPC.

[pete_auau 1,158]

Hi i used to use rex as well and got the reg version of fsuipc as well, still had the s turns still so now i use rex as my textures and use ase as my weather engine and have no more s turns or wind flunctuations that u had with rex.

[Paul Deemer 13]

All is explained here: http://forum.avsim.n..._1#entry2127745

[martin-w 3,235]

Hi i used to use rex as well and got the reg version of fsuipc as well, still had the s turns still so now i use rex as my textures and use ase as my weather engine and have no more s turns or wind flunctuations that u had with rex.

I'm very surprised you still had S-turns with FSUIPC correctly set. If the suppress turbulence box, and the ones next to it are ticked I get no s-turns at all.

[pete_auau 1,158]

I'm very surprised you still had S-turns with FSUIPC correctly set. If the suppress turbulence box, and the ones next to it are ticked I get no s-turns at all.

yea but not as bad if i hadnt it set but the wind flunctuation were the worst made the speed tape go mad but iam happy now no s turns and no wind flunctuation

[martin-w 3,235]

sounds like you weren't using the right FSUIPC settings.Wind fluctuations can be easily eliminated with the right FSUIPC setting. I use 8 seconds per knot, and suppress turbulence variance gusts.Works perfectly, no S-turns and no crazy wind shifts.FSUIPC would solve the OP's issue, but glad you are happy with your choices Pete.