Still Trim issues with Sp1b

[777simmer 117]

Yes Rob, I do have this behaviour.Jumps about as you describe. Sometimes about a knot, sometimes 2 or 3 knots. 

Ok thx for the feedback Martin.

 

If I get the same on my new yoke (it just arrived :-) and I should have some time tonight to test it) then I guess that one alone is worth a support ticket.

 

Because if you are trying to trim by feel, initially things go well ofcourse when you hold the trim switches down to correct for like 20-30kt out of trim feel.

 

But if trim ref speeds jumps about like it does on my system then it just takes way too long to establish a final final exact trim setting.

Even with the blib feature because that does not allways work for me either.

 

And I often end up in a situation where I do not know if pitch goes up/down slowly because I am out of trim by a few knots, or because a winds gust or whatever just caused it.

Causes endless trimming sometimes :-(

[evaamo 549]

I get the same jumpy behaviour by the  FBW marker and that's one of the reasons why, as mentioned in my last post in this thread,  I tried flying without the marker cheat. The result was that flying the aircraft felt unnatural (to me at least) and ended up using the marker in my last flight again. Fly it like a Cessna doesn't apply (again, in my case), so I just ended up using the darn marker as a sort of dial-a-flap: dial-a-trim ref speed and be done with it. Not the best solution, I know, and that's why I mentioned in my last post I can hardly describe hand-flying the 777 as a joyful experience (like my real world 777 flying buddies tell me it is).

 

Then again, this is my very own subjective experience.

cheers

-E 

[scandinavian13 5,192]

 

 

Even with the blib feature because that does not allways work for me either.

 

Blip...with a 'p.'

 

'Blip' as in "a blip of the throttle" (predominant linguistic use: racing) or defined as "a small or brief interruption."

 

Sorry - after seeing it so much, it finally pushed me over the Pedantic Grammarian cliff.

[777simmer 117]

Ok, blip......... will try to remember that.......still, blib is better than bubble no?

Where did that even come from?

 

 

I get the same jumpy behaviour by the FBW marker and that's one of the reasons why, as mentioned in my last post in this thread, I tried flying without the marker cheat. The result was that flying the aircraft felt unnatural (to me at least) and ended up using the marker in my last flight again. Fly it like a Cessna doesn't apply (again, in my case), so I just ended up using the darn marker as a sort of dial-a-flap: dial-a-trim ref speed and be done with it. Not the best solution, I know, and that's why I mentioned in my last post I can hardly describe hand-flying the 777 as a joyful experience (like my real world 777 flying buddies tell me it is).

 

Then again, this is my very own subjective experience.

cheers

-E

 

last post here...ok....no one can force you to stick around.

 

But at least submit a ticket that you are having trouble with how the FBW trim system works. (just tell them exactly exactly what you told us a few posts agao)

The more people let them know that something is not right, the better the chance that someone will look at it!

[evaamo 549]

no one can force you to stick around.

 

hey, I don't plan on going anywhere, love the 777 too much to give up on her ;-)

 

Will try opening the ticket later on.

 

By the way, it seems I may be the culprit of calling the marker a "bubble"... IMHO that's better than "blib " :-P (it's a joke, just in case).

 

cheers

-E

[martin-w 3,234]

I call it a MAGTIT.

 

Magical Attention Grabbing Trim Indicating Thingy.

[kevinh 409]

I've not paid ultra close attention to this thread, as I don't seem to be having the issues you guys are.

 

 

This issue where you have to centre the yoke/Joystick before the trim applies isn't happening to me. I can trim up or down, whether the controls are centred or not.

 

However... what I find utterly weird, is that if I fly in trim at lets say 300 knots, and without altering the trim, decelerate right down to 190 knots, all I require to fly straight and level is a very small back pressure on my joystick.

 

Conversely, if I do it the other way round, namely fly in trim at 190 knots, and then without changing trim, accelerate to 300 knots, I require maximum forward movement of my joystick, as far as it will go, and despite this it's still not sufficient and I climb rapidly.

 

I may be wrong, but it seems as if their is a disharmony in regard to trimming. Surely I shouldn't require minimal back pressure when decelerating, but maximum forward pressure when accelerating.

Martin,

 

Is this with the -200? I think the reason you see this, as I do, is that the required trim position only varies by about 0.5 units over that speed range. So you can slow down to 190 and still nearly be in trim.

 

I don't know how much the aerodynamic trim position varies with airspeed in the real aircraft. It doesn't seem to move much in the PMDG -200LR. The -300ER trim position moves around 1.5 units over the same kind of speed range.

 

The real 777 FBW applies an increasing pitch down as the speed reduces (because the FBW is still trimmed for the original high speed). So by the time you get down to 190 you should have to be pulling back very hard indeed.

 

Note this would still happen if the trim position in the real aircraft only changed by 0.5 units as with the PMDG sim. The out of trim pitch effect comes from the FBW, not aerodynamic trim.

 

PMDG have not got this speed trim effect right. If they did they would not have to reduce elevator authority to get some kind of trim feel.

 

Kevin

[777simmer 117]

Hi Guys, I got a response from Ryan by PM:

 

 

quote

 

Rob,

I tried the 210-310 thing in both the 200LR and the 300ER .(the code is exactly the same for both of them so I'm not sure where the comments about the 300ER working better are coming from - that's not possible from the code's perspective)

 

Here's the deflection I needed to stay level at 10,000 feet while doing this on my Saitek X52:

 

 

As you can see there, it's almost fully back - I see the equivalent nose down deflection needed when doing the opposite flying at 310 with the reference speed at 210. As I input trim while holding this deflection, the nose starts to move (can see this on the PFD) and I release the deflection gradually to maintain level flight as the trim gets closer to the actual airspeed. As best I can tell on my hardware this is working exactly as we intended it to.

 

Erratic ref trim speed movement - there's nothing that can be done here unfortunately - every controller has a different repeat rate for its buttons. That comes from the hardware and from windows. The way we set it up produces the roughly 1 second per 10 knots rate on my X52 with the slider in FSX maxed. You can try turning that slider down and see if it makes it more controllable for you. On the real plane, as you know it's, an analog type rocker switch that is most likely generating a constant voltage when held down, not a digital set of discrete repeats. The computers I'm sure interpret that constant voltage as a constant rate of trim application - that's not really possible in our simulation because of the way held buttons work on controllers

 

unquote

 

 

so from that I guess we can conlude that my system (and Martins and that of some others) is not behaving correctly.

(even though Martin CAN trim by feel)

 

Yoke/elevator authority should be becomming less and less responsive in either out of trim condition.

The only one who has reported this kind of response so far is Kevin (and Ryan).

 

 

additionally:

I have in the mean time installed my new Saitek Cessna Yoke.

Saitek drivers are installed and used (not windows default drivers).

 

FSUIPC removed

Dead zone introduced for aileron and elevators in the Saitek driver.

PMDG CDU deadzone.....I changed it from 1 to 10 and saw now difference (maybe this requires an FSX reboot?)

The test below was done with 3.

 

And I get the exact same wrong response as with my old yoke :-(!

1) reduced elevator/yoke in one direction (flying way faster than trim ref speed)

2) increased elevator/yoke authority in the other out of trim direction (flying way slower than trim ref speed)

 

So number 2) is wrong......and guess what??!!

- I can trim by feel in case number 1) (the correct auhtority situation)

(in this case while holding full nose down yoke deflection, adding nose down trim returns authority back to normal and I have to slowly reduce elevator deflection)

- I can NOT trim by feel in case number 2) (the in-correct authority situation)

(in this case, while keeping the nose up with just a tiny little bit of yoke back pressure, adding nose up trim does not return authority.)

 

That can not be a coincidence.

 

 

Martin.....if you try my number 2) situation are you sure you can trim by feel there as well?

Fly level in 5000ft or so (not FL350 or something crazy please) at 310kt.

Fly in-trim, so blue FBW trim ref speed also to 310kt.

 

Now reduce speed (actual speed to 250kt) but do not trim!

You should have to pull slighly to keep the aircraft level.

Once at 250kt, establish that pitch that holds level flight and hold pitch constant....  you need to fly precise....you must first find the YOKE or STICK POSITION that keeps zero ft/min.

 

Once you have found this.....do NOT change that POSITION/DEFLECTION again

(this is important because if you change position/deflection we can not conclude then if a pitch up or down moment was caused by you or by a trim input!! And we also want to prevent the yoke from ever touching the neutral position!) 

 

Now with that constant yoke position/deflection, add nose up trim untill the blue FBW trim ref speed indicator (or MAGTIT) also is at 250kt.

 

The theory is that this should return elevator effectiveness to normal and should thus result in a STRONG pitch up tendency (see now why it is important to make sure the yoke position/deflection does not change even the slightest?!).

 

In my case it does nothing......thus I can not trim by feel in this direction!

Of course not!!!!.......with yoke/elevator autority already maxed....it is ofcourse not even possible that a return to normal authority would cause a pitch up moment!

You need to have reduced authority like Kevin and Ryan for that to work!! 

 

When I let go of the yoke, trim is applied, and the nose goes up.

 

 

I do not know how to fix this thing :-(

 

I only have a few options left I can think of.

1) create a fresh flight (I used a saved SP1b flight created when my old yoke was still attached for the above test)

2) test CDU deazone settings a little bit more with FSX reboot inbetween (but I fail to see how that would reverse my out of trim over-sensitive behavior)

3) uninstall and reinstall the PMDG777-200 and apply SP1b again.

4) by the -300 and see if that somehow magically changes things for the -200

 

Any thing else I have not thought of?

[martin-w 3,234]

Martin,

 

Is this with the -200? I think the reason you see this, as I do, is that the required trim position only varies by about 0.5 units over that speed range. So you can slow down to 190 and still nearly be in trim.

 

 

Yep, it is the 200 Kevin.

 

 

so from that I guess we can conlude that my system (and Martins and that of some others) is not behaving correctly.

Well Rob, Ryan's might be functioning correctly in this respect, but mine, and Kevin's, and yours, and others isn't!

 

 

 

The only one who has reported this kind of response so far is Kevin (and Ryan).

 

 

 

Kevin has the issue too Rob, namely minimal joystick deflection when well under trim speed. See Kevin's response above.

[martin-w 3,234]

Martin.....if you try my number 2) situation are you sure you can trim by feel there as well?

 

Fly level in 5000ft or so (not FL350 or something crazy please) at 310kt.

 

Fly in-trim, so blue FBW trim ref speed also to 310kt.

 

Rob... I tried your scenario exactly as you describe.

 

Yes, In that scenario I do NOT have to return the joystick to neutral to trim. There was indeed a strong pitch up, as you would expect.

 

 

However... Guess how much joystick deflection I required to stay level at 250, trimmed for 310???

 

6mm I kid you not.

 

My full joystick deflection is 80MM.

 

Absolute minimal rear defection required. So in other words I am very close to neutral. Don't think I entered neutral, but as I say very close, so quite conceivably it may have been close enough to have impacted the results.

[777simmer 117]

Rob... I tried your scenario exactly as you describe.

Yes, In that scenario I do NOT have to return the joystick to neutral to trim. There was indeed a strong pitch up, as you would expect.

However... Guess how much joystick deflection I required to stay level at 250, trimmed for 310???

 

6mm I kid you not.

 

My full joystick deflection is 80MM.

 

Absolute minimal rear defection required. So in other words I am very close to neutral. Don't think I entered neutral, but as I say very close, so quite conceivably it may have been close enough to have impacted the results.

Ok interesting that you can still trim then and I can not.

 

I will post what happens after trying out the above mentioned options.

 

thx for the feedback.

 

EDIT: And yeah those 6mm are rediculous......something is realy wrong there

 

Kevin has the issue too Rob, namely minimal joystick deflection when well under trim speed. See Kevin's response above.

Yes I read Kevins responses.

The way I understand it he has what Ryan has.

 

when out of trim......less yoke authority.

But in each out of teim situation only in one yoke direction.

So only in the push direction in one out of trim situation (pull still had normal response)

and only in the pull direction in the other out of trim situation (push normal).

 

I think Ryan will has that as well, but he just did not mention it.

[geolpilot 88]

 

 

So one click on the trim button equals 1kt trim ref speed?
Allways (except during blib)?

 

Sorry for late reply, been busy on my Lua Scrip (eeeeh)

 

1 sec click on the trim is giving me +-10kts ref speed change, as long as I am more than 3-5kts away from current airspeed (otherwise blips - quick flick vs 1 sec can be a bit tricky - maybe my trim switches are a bit worn!). This is normally what I get, but can be erratic, at times I only get 5kts per 1 sec..

 

In the speed way below ref trim speed test, although I can trim by feel, I confirm that I have to hold very little back pressure, so it is quite hard to stay away from nuetral pos and hold the VS constant; compared to the opposite test, far greater forward pressure needed, so feeling is really "there" to trim out. Seeing same assymetry as most, (and unfortunately as you are still seeing after all the effort/cost to get a new yoke)

 

Rob

[martin-w 3,234]

In the speed way below ref trim speed test, although I can trim by feel, I confirm that I have to hold very little back pressure, so it is quite hard to stay away from nuetral pos and hold the VS constant; compared to the opposite test, far greater forward pressure needed, so feeling is really "there" to trim out. Seeing same assymetry as most, (and unfortunately as you are still seeing after all the effort/cost to get a new yoke)

So, yet another person with the same asymmetry issue.

 

I would bet that as most fly on autopilot, and rarely hand fly except just prior to landing, that it's unnoticed.

 

I'm speculating this is an issue for a great many.

[777simmer 117]

Yes, me think the same!

 

But what causes it?

Corrupt SP1 download?

 

I will PM Ryan and see what he thinks.

[martin-w 3,234]

But what causes it?

 

Who knows.

 

Just because it only occurs for some, doesn't necessarily imply it's not an issue with the simulation. There have been plenty of bugs in the past, that despite present only for some warranted a fix. An issue in the code, wouldn't necessarily manifest itself for all.

 

So said me, devoid of any experience at coding. :smile:

 

As we said though, most will be disengaging the autopilot at 1000 feet or so, when the aircraft is already in trim, thanks to the A/P. So not having to trim, they wouldn't notice the issue.