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aceridgey

Still Trim issues with Sp1b

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@Alex,

 

Quoting Kyle directly from post #176 in this thread:

 

"Fitting for forum trolls and those who prefer to trash things because they can't get something that's not supposed to work for them, to work...

 

...if you catch my drift."

 

I'm really not sure how else you can interpret this, Alex?     

 

 

Signed,

 

Bruce Arnold

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Hey guys..lets keep this thread to our findings.Atleast respect the time people have put in testing the experiences from Rob and others.From my perspective, I don't think Kyle had a problem with sharing the findings on this thread.I think he had a problem with people expecting PMDG to monitor this thread as a defect tracking tool or something.So he just asked us all to report this on support forum since now there is some data from people. I think that's all he meant.And Arnold I also definitely found those videos and all a bit on the teasing side of things than being humor.Lets take this data and report it to PMDG on the support portal and then leave it to them.And if we need to be testing any more scenarios we can keep doing on this thread and reporting the findings here for others.


@Alex,

 

Quoting Kyle directly from post #176 in this thread:

 

"Fitting for forum trolls and those who prefer to trash things because they can't get something that's not supposed to work for them, to work...

 

...if you catch my drift."

 

I'm really not sure how else you can interpret this, Alex?     

 

 

Signed,

 

Bruce Arnold

I would interpret it as a person who just wants to rant about things but does not want to take necessary steps to help it fix through the right channel.I don't think he implies being a pirate.Personally if it were meant for me, I would still not think that he is terming me as a pirate.All he is saying is raise it on the support portal with the data. A lot many requests on support portal will have PMDG to take a serious look at it.


And please do not take my comments personally too.


Thanks,
Pankaj Dekate
 

Boeing777_Banner_Pilot.jpg

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From my perspective, I don't think Kyle had a problem with sharing the findings on this thread.I think he had a problem with people expecting PMDG to monitor this thread as a defect tracking tool or something.

 

Bingo.  Hit the nail on the head.


Kyle Rodgers

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If you have a problem with Kyle, approach him privately,

 

Actually it should have been Kyle that did that.

 

Catalysts and all that...

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@Alex,

 

Quoting Kyle directly from post #176 in this thread:

 

"Fitting for forum trolls and those who prefer to trash things because they can't get something that's not supposed to work for them, to work...

 

...if you catch my drift."

 

I'm really not sure how else you can interpret this, Alex?     

 

 

Signed,

 

Bruce Arnold

 

 

Bruce,

 

Many of us are silently following this thread absorbing some good info. You are contributing absolutely nothing to this thread except poor humor,  sarcasm, and what seems like general trolling.  

 

Please, either start contributing something constructive, log a ticket with PMDG or just sit back &  make yourself a warm cup of STFU while the rest here try to resolve this issue..


Rob Prest

 

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Enter Rob Prest with, again, words of wisdom and sense :-). Glad you're monitoring things also mate.

 

 

 

On track to thread.

 

This issue is also very apparent on the takeoff roll (FBW Trim REF speed seems to activate above a certain altitude, is it 50ft/100ft?.) When i take off and accelerate up, I can see and feel the moment the FBW kicks in, as I get a very noticable 'bobble' (a sudden increase or decrease in pitch).

 

Any others finding that (this was in the 200LR today)

 

Alex


Alex Ridge

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Alex..can you post your exact scenario?I can try it at home after work.I have been flying 300 till now so i haven't seen any such.I can try with 200 later in the day.


Thanks,
Pankaj Dekate
 

Boeing777_Banner_Pilot.jpg

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Alex..can you post your exact scenario?I can try it at home after work.I have been flying 300 till now so i haven't seen any such.I can try with 200 later in the day.

 

Just a small one initially (my more detailed ones are posted earlier in the thread), use a derate so you're not powering away too much with a decent Takeoff weight.

 

Takeoff, and when you see the trim ref speed appear on the speed tape (you're joystick should be pretty neutral at that point or slightly pulled up) see what the aeroplane does

 

Cheers,

 

Alex


Alex Ridge

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If people want attention drawn to the matter, submit support tickets.

 

We all know that the team lurks here sometimes, but this is the community support forum, so you can't expect they're simply just going to pop in on a whim.

 

 

You gonna submit a support ticket, or do you not want to for some reason?

I actually submitted a support ticket before posting in here.


captainhenrychen-1.jpg


Boeing777_Banner_Pilot.jpg


 


James Bennett

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Ok..Here is something exciting with respect to the 777-200. I did not see this with 777-300. I was able to trim the 777-300 by feel. But I had a hard time trimming the 777-200.And guess what , for the 777-200 it applied the trim only when the control column was neutral. Till the time I was pulling back on the yoke to maintain 250 knots and level flight it would not trim. I was expecting it to maintain level flight but if i released the yoke it had a tendency to descend big time.So i just gave it a slight climb rate (arnd 200 ft/min) and immediately released my yoke to neutral..yippie the trim immediately applied and it was able to maintain level flight.Till that time it was doing a see-saw. So i too do concur that it happens with 777-200 only but cannot see the same with 777-300.Without the FBW marker displayed its going to be tough to trim the 777-200 by feel alone.

 

This definitely makes the case for a support ticket.I am going to do some testing tomorrow too.And I will capture the events in a video.I am just not able to figure out how do i capture my voice through the microphone using shadow play.I have put the audio capture to always on in Shadow Play.Perhaps I will figure it out tomorrow or use mouse gestures  in the video. :P


Alex: I do see that it pitches up a bit when the FBW marker is displayed.At the moment I am still giving it a benefit of doubt attributing it to my pitch control.I will once again do some testing tomorrow for this scenario too.


Thanks,
Pankaj Dekate
 

Boeing777_Banner_Pilot.jpg

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Ok..Here is something exciting with respect to the 777-200. I did not see this with 777-300. I was able to trim the 777-300 by feel. But I had a hard time trimming the 777-200.And guess what , for the 777-200 it applied the trim only when the control column was neutral. Till the time I was pulling back on the yoke to maintain 250 knots and level flight it would not trim. I was expecting it to maintain level flight but if i released the yoke it had a tendency to descend big time.So i just gave it a slight climb rate (arnd 200 ft/min) and immediately released my yoke to neutral..yippie the trim immediately applied and it was able to maintain level flight.Till that time it was doing a see-saw. So i too do concur that it happens with 777-200 only but cannot see the same with 777-300.Without the FBW marker displayed its going to be tough to trim the 777-200 by feel alone.

 

This definitely makes the case for a support ticket.I am going to do some testing tomorrow too.And I will capture the events in a video.I am just not able to figure out how do i capture my voice through the microphone using shadow play.I have put the audio capture to always on in Shadow Play.Perhaps I will figure it out tomorrow or use mouse gestures  in the video. :P

Alex: I do see that it pitches up a bit when the FBW marker is displayed.At the moment I am still giving it a benefit of doubt attributing it to my pitch control.I will once again do some testing tomorrow for this scenario too.

 

Hi Pankaj,

 

I am almost certain that it's not a variant specific issue. I get the same thing in both the 300er and 200lr.

 

Thank you for continuing to test though :-)

 

 

Alex


Alex Ridge

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OK, over the last few days I have been watching this thread closely (see it nearly "went south" overnight out east here), testing a lot, and reading up on how it is supposed to behave. Based on certain posts here, I am more than a little concerned that there is a lot of misunderstanding of how the B-777 FBW is SUPPOSED to work, leading to reactions that vary from "it is totally broken", to it "works, but not as it should", or  "its faulty because trim is only being applied when the yoke is nuetralised" etc. Based on my observations, and the article I reference, I would urge some users to maybe re-think more than just a little bit!

I also think that some pre-conceptions are leading some users to spend a lot of time searching for setup problems, swopping out different controllers, etc, instead of just getting on with flying, and practising the technique required to fly the 777 manually.

I am going to be referencing the following article in this and subsequent posts. I think a careful, thoughtful re-read and analysis of this article is a good idea at this juncture;

"Boeing B-777: Fly-By-Wire Flight Controls", Gregg F Bartley, Boeing.
Available at www.davi.ws/avionics/TheAvionicsHandbook_Cap_11.pdf

Read it already; maybe you need to read it again (or at least page 10)!

Rather than one (very) long post I will divide this up into sections.

PART ONE; How stab trim behaves ON THE GROUND, and testing your yoke / joystick controls.

Bartley, Quote 1, Page 10: "When the airplane is on the ground, the pitch trim switches DO trim the horizontal stabilizer directly." (Implies they do not in the air; mmmmmmm, say what?!!! Thats for PART TWO post)

So, Try this ground test to check if your controls are working properly (need elec power source, ground or APU, and elec. hydraulics enabled), and also to check that PMDG have programmed ground behaviour by the book.

Experiment 1

  • In the VC set stab trim 6
  • Go to outside spot view (or if have Ezdok, set up an outside camera of the Tail/Stabilisers).
  • Hold Full Back on yoke. See elevator deflection. Yes? GOOD.
  • Trim UP (back) while holding the yoke full back - See the stabiliser moving - Yes? GOOD; Trim IS enabled while the yoke is out of neutral (at least on the ground)!
  • Release the yoke and trim the stabilser back to central position.
  • Push yoke full forward - See elevator deflection. Yes- GOOD.
  • Trim down (forward) while holding the yoke full forward - See the stabiliser moving - Yes? GOOD; Trim IS enabled while the yoke is out of neutral (at least on the ground)!

Experiment 2

  • While still in outside view, trim stabiliser to middle position.
  • Hold yoke fully back, but trim DOWN (hold trim switch forward)- see the stabiliser move? No? GOOD. System will not allow trim in direction opposite to yoke force (at least on the ground)!.
  • While still holding trim button DOWN (forward), release yoke to neutral. See stabiliser start to move in trim direction? Yes? GOOD. Allows trim to come in now because there is no opposite force on the yoke!
  • Trim stabiliser back to middle position.
  • Hold yoke fully forward, but trim UP (hold trim switch backward)- see the stabilser move? No? GOOD. Will not allow trim in direction opposite to yoke force.
  • While still holding trim button UP (backward), release yoke to neutral. See stabiliser start to move in trim direction? Yes? GOOD. Allows trim to come in now because there is no opposite force on the yoke!

If you get the above results for these experiments, I respectfully suggest that;

  • There is nothing wrong with your yoke/joystick hardware and setup, and you can stop playing with settings and hardware, and concentrate on the next step! What happens in the AIR!?
  • PMDG have programmed the stab trim / elevator behaviour exactly as is expected when on the ground.

For those who do not have the time (or inclination :angry:) to test this for themselves, here is a 10 min Youtube Video I made showing the results summarised in this post.

 

OK video is taking a while to upload. I will post now and make an edit with the link later.

 

Rob


Robin Harris
 

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Hopefully this will clear things up


I7-800k,Corsair h1101 cooler ,Asus Strix Gaming Intel Z370 S11 motherboard, Corsair 32gb ramDD4,    2  ssd 500gb 970 drive, gtx 1080ti Card,  RM850 power supply

 

Peter kelberg

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Untill I get a response of how the system is supposed to work (in respect to elevator authority) by PMDG - nothing is cleared up.

 

As do going outside and looking at aircraft control surface - as far as I know animations have nothing to do with how the airplane acutally reacts.

 

I think you could make the animation of the elevator going up when you push on the yoke and still have the aircraft pitch down in flight.....but I could be wrong.


Rob Robson

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Yes animations has nothing to do with what the airplane is supposed to do.Logically they should be in sync.But just because animations are fine would not imply that the underlying logic is also fine.


Thanks,
Pankaj Dekate
 

Boeing777_Banner_Pilot.jpg

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