Jump to content
Sign in to follow this  
Guest Erups

Sidewind reaction????

Recommended Posts

Guest Erups

I noticed that in case of heavy sidewind, the PMDG although following correctly the plan with no lateral deviation, maintains a heading in favor of the wind.I mean that if you're flying 270, with 360/50 wind, the pmdg will not maintain a heading higher of 270 (say 278) but lower instead (so something like 262).That's against physics laws :DAlso i just noticed (while taxiing at small airports like LOWI... :D)that, even if i have the correct assignements for the differential brakes (F11 and F12) only left seems to work, right have no effect.Anyone can confirm this?BRClaudio

Share this post


Link to post

Hi Claudio,The display is working fine. I believe you are looking at the ground track and not the heading. In your example your heading is 270 but your ground track will be 278 due to the cross wind. There is a better explanation of this in the manual or you can do a search. There are a few good threads out there explaining this.

Share this post


Link to post
Guest Erups

I have to clarify my statement a bit.What i described has to be referred to the ND display, and the HDG numbers i gave should be referred to the TRK of the ND display.To rephrase it:what i saw is that, when haveing sidewind from my right, my TRK was left of the magenta line, instead of right.BrClaudio

Share this post


Link to post
Guest Erups

I didn't write it clear enough, so i reposted below.But probably it was a one time only thing, because i tried to have this phenomenon show again without success... :-hmmm

Share this post


Link to post
Guest Erups

Unfortunately i wasn't seeing phantoms here, look at the screenshothttp://forums.avsim.net/user_files/78764.jpgAt the moment i have a 60/40 wind and the situation is the same.For this shot i was in hdg mode, but yesterday it happened in LNAV mode.I may add that i can see this phenomen visually:if i set a tower view to the near left of the airplane, during the view the plane translates to the left, and the view comes to be on the right of the airplane.BRClaudio

Share this post


Link to post

"For this shot i was in hdg mode, but yesterday it happened in LNAV mode."For HDG mode, these indications are normal. You are maintaining a heading of 290 and you are being blown sideways along a ground track of 286. Heading is where your aircraft nose is pointing, track is where your aircraft is actually going.Hope this makes sense.Cheers.Ian.P.S. (Edit) Or to put it another way, if YOU were a pedestrian walking NORTH across a pedestrian crossing and a large truck came racing down the road from your right (the EAST) at 60mph... if it hit you, which way would you go? Eastwards? (I don't think so) ;-)

Share this post


Link to post

>came racing down the road from your right (the EAST) at>60mph... if it hit you, which way would you go? Eastwards? (I>don't think so) ;-) :-xxrotflmao


PPL(A)

Share this post


Link to post

>Or to put it another way, if YOU were a pedestrian walking NORTH >across a pedestrian crossing and a large truck came racing down the >road from your right (the EAST) at 60mph... if it hit you, which way >would you go? Eastwards? (I don't think so) ;-) A very good and informative simile. ;-)But Ian, now suppose this pedestrian were in LNAV mode and the truck hit from the east at 60 mph. Now what happens?Cheers,

Share this post


Link to post

I understand the fact that the wind is pushing the nose left but shouldn't the aircraft be pointing more to the right to maintain the track? I.E. pointing the engines in to the wind instead of with the wind? I would think that with a heading to the left the aircraft would go off track but with a heading to the right it would stay on track. I'm confused :( Edit:Spelling


 ________________________________________________________________________________

 

i9 10800K | 16GB RAM | RTX 3080 | Windows 10 | 

Saitek x-45 | Bravo Throttle | Alpha Yoke | CH Pedals | Logitech Radio Panel | SmoothTrack | AAO

Share this post


Link to post
Guest Erups

>But Ian, now suppose this pedestrian were in LNAV mode and the>truck hit from the east at 60 mph. Now what happens?I think i have earned this :)

Share this post


Link to post

JeremyWhen in HDG mode the plane will only try to keep the heading selected on the MCP. Any wind will blow it off any intended path. The A/P is in fact not trying to keep a path.Now, in LNAV mode the A/P will try to keep the path or TRacK and will therefore adjust its HeaDinG to compensate for any wind.Got it? Or did I just confuse it even more? ;-)Cheers,

Share this post


Link to post

No Matt I understand what you are saying but what is confusing me is that when in LNAV it seems that the A/P turns the aircraft with the wind to correct instead of into the wind to correct. If the wind is blowing from the right the nose is turned to the left of the intended track, instead of to the right.


 ________________________________________________________________________________

 

i9 10800K | 16GB RAM | RTX 3080 | Windows 10 | 

Saitek x-45 | Bravo Throttle | Alpha Yoke | CH Pedals | Logitech Radio Panel | SmoothTrack | AAO

Share this post


Link to post
Guest Erups

>No Matt I understand what you are saying but what is>confusing me is that when in LNAV it seems that the A/P turns>the aircraft with the wind to correct instead of into the wind>to correct. If the wind is blowing from the right the nose is>turned to the left of the intended track, instead of to the>right. That's exactly what i was saying :-roll BRClaudio

Share this post


Link to post

Ok guysTwo small bed time stories ;-)The story of LNAV:AP -I have to keep this TRACK that is headed 270

Share this post


Link to post
Guest Erups

>PIC -Why is the aircraft HEADING south of my TRACK ?Actually it's the TRACK which is south of the HEADING ;)Story part #2:wind - Hi again airplane, this is wind blowing on you as usualap - hi wind, how do you do today?wind - fine thanks, blowing as usual, and you?ap - fine, following my lnavwind - you sure?ap - ya, why?wind - cause i am blowing on youap - as usual, and as usual i am correcting, can't you see? you're blowing from my right, i have to keep a track of 270, and i'm pointing 262.... mhhh.... huston i'll call you back!How does this one sound?:DBRClaudio

Share this post


Link to post

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  
  • Tom Allensworth,
    Founder of AVSIM Online


  • Flight Simulation's Premier Resource!

    AVSIM is a free service to the flight simulation community. AVSIM is staffed completely by volunteers and all funds donated to AVSIM go directly back to supporting the community. Your donation here helps to pay our bandwidth costs, emergency funding, and other general costs that crop up from time to time. Thank you for your support!

    Click here for more information and to see all donations year to date.
×
×
  • Create New...