how to hand fly with C*U law aircraft

[whoispankaj 51]

I will give an example, in a turn in level flight, under the command of autothrottle but hand flying, i am set to maintain a given speed and when i begin the turn the aircraft will begin to nose dive or climb when it should not, the throttles should change to fit the speed commanded and they do, but for some reason i am left to trim the aircraft myself else it becomes "out of trim" and climbs or descends rather sharply.

I have tried this scenario ..and it works well for me..the airplane does not jump up or down or goes out trim..it keeps the speed and keeps the attitude..

Whoa...what? You mean you trim for stability? That can't be! Pilots never do that. Kyle just told me so. But you're a real 777 pilot right? I am now sooooo confused!

 

No such thing as trim speed either, in addition to trim stability in maritime circles: https://www.google.co.uk/#q=trim+for+speed

 

Lordy mamma, whats next? Does he pull all his knowledge out of his &@($*?

 

Richard Wells

I think you are taking things out of context..what he meant is get to your desired speed and attitude and then trim out the forces..

[777simmer 117]

Whoa...what? You mean you trim for stability? That can't be! Pilots never do that. Kyle just told me so. But you're a real 777 pilot right? I am now sooooo confused!

 

No such thing as trim speed either, in addition to trim stability in maritime circles: https://www.google.co.uk/#q=trim+for+speed

 

Lordy mamma, whats next? Does he pull all his knowledge out of his &@($*?

 

Richard Wells

Ok everybody calm down please.

 

I do not trim for stability.

 

Real aircraft:

You trim so that control forces are zero.

But when you are out of trim, when you let go, the nose goes up if you have too much nose up trim and vice versa with too much nose down trim.

And the more out of trim you are the stronger the pitch up/down moment would be.

Flying like that is really difficult because it is hard to keep pitch stable, as in....where you want it (which is why a trim wheel was invented in the first place).

When out of trim a lot, even a mini relaxation of the yoke creates a sharp pitching moment.

So you trim for speed (not stability) but if you do not trim correctly you end up with an unstable pitch axis, that is all I meant.

 

PMDG777:

With the PMDG777 I can not feel at what point I have set a FBW trim ref speed that matches my current speed because one moment I let go of the yoke and pitch stays where I want it (pitch is stable), I look away one second and the next moment pitch goes up or down (so pitch not stable after all). And if I then check the FBW trim speed it is because I am still off by 20kt!

So I can not (so far) find that exact FBW trim ref speed that keeps my pitch stable unless I display the FBW trim ref speed.

[jcomm 5,923]

Rob,

 

although I perfectly understand your suggestion of using the elevator instead for all of this stuff, and make the 777 and it's trim act like other aircraft in FSX, I also know that, should PMDG have taken that approach, a few of the users would soon start "noticing" that the way the aircraft FBW trims is unrealistic, because it should first use the elevator, than the stabilator, etc....

 

What PMDG did, IMO, was probably the best approach to modelling this complex FBW system, as they say, within the confines of what FSX allows to, specially when users do not have a complex Force Feedback system to go with it.

 

Not being able to model the articficial forces in the control column, they chose to use two alternative methods:

 

1) Relaxation of the pitch throw / sensitivity, directly proportional to the forces required IRL to operate it;

2) Displaying the trimmed speed cue on the speed tape.

 

I think your notes Rob, and the dedication to understanding what was going on, using your precious RL experience is simply as remarkable ( it's a delight to read your notes, your comments, the tests you actually ran on the real thing, etc... ) as PMDG's effort to bring this model to the highest possible level of accuracy possible in the MSFS FSX platform.

 

This being said, I do not even have FSX installed anynmore, but have been seriously tempted to try it again just for the sake / pleasure of re-installing and testing this model :-)

[777simmer 117]

Rob,

 

although I perfectly understand your suggestion of using the elevator instead for all of this stuff, and make the 777 and it's trim act like other aircraft in FSX, I also know that, should PMDG have taken that approach, a few of the users would soon start "noticing" that the way the aircraft FBW trims is unrealistic, because it should first use the elevator, than the stabilator, etc....

 

What PMDG did, IMO, was probably the best approach to modelling this complex FBW system, as they say, within the confines of what FSX allows to, specially when users do not have a complex Force Feedback system to go with it.

 

You are probably right.

But I will put in a support ticket anyway if SP1b is the same

Who knows maybe they have overlooked something.....they are only human after all :-)

 

Thx for the nice words, appriciate that :-)

[martin-w 3,235]

although I perfectly understand your suggestion of using the elevator instead for all of this stuff, and make the 777 and it's trim act like other aircraft in FSX, I also know that, should PMDG have taken that approach, a few of the users would soon start "noticing" that the way the aircraft FBW trims is unrealistic, because it should first use the elevator, than the stabilator, etc....

I disagree, if PMDG had taken that approach... PMDG simply stating that it was necessary to achieve a realistic feel would have been enough, and accepted by the majority. Utter realism is pointless if it renders an add-on harder to fly than it should be.

 

Realism for the sake of realism is sometimes detrimental to our objective, our objective to simulate a semblance of the real flying experience.

 

Take helicopters for example. Often notoriously difficult to fly in the sim. Why, because they are often coded on the numbers. Trouble is, in a real helicopter you have various sensory clues telling you what the machine is doing, that you don't have in the sim. Thus, helicopter sims are better coded to match the degree of difficulty to fly.

 

This is flight simulation after all, where we actually simulate flying the machine, not an engineering course.

[martin-w 3,235]

Even then, it's best to do so with a little more tact...

 

Had to smile when I read that Kyle was advocating tact.

[James Bennett 52]

Had to smile when I read that Kyle was advocating tact.

 

[kevinh 409]

With the PMDG777 I can not feel at what point I have set a FBW trim ref speed that matches my current speed because one moment I let go of the yoke and pitch stays where I want it (pitch is stable), I look away one second and the next moment pitch goes up or down (so pitch not stable after all). And if I then check the FBW trim speed it is because I am still off by 20kt!

So I can not (so far) find that exact FBW trim ref speed that keeps my pitch stable unless I display the FBW trim ref speed.

With my set up the elevator begins to drive towards the trim speed as soon as I release control pressure. Maybe you could try adjusting the pitch deadband in the CDU so it doesn't try and hold the flight path initially.

 

For me, displaying the trim speed doesn't help. It removes all the feel element from trimming. Basically you only have to press the trim switch until the FBW marker matches current speed. You might as well have an auto trim switch. I'm finding the more I fly the 777X post SP1 the easier it gets to set trim. I can get it close by feel then use the blip trim to set it exactly.

 

Hopefully PMDG will be able to make the trim more instinctive somehow in the next update.

[777simmer 117]

Utter realism is pointless if it renders an add-on harder to fly than it should be.Realism for the sake of realism is sometimes detrimental to our objective, our objective to simulate a semblance of the real flying .

Well said......I tried to say the same in my report.

[scandinavian13 5,192]

Guys,

 

I'd argue that some of the stuff here has probably helped the devs, but at this point, they've pushed a couple updates to the team (as I think one of the team members noted).  So, unless you've spotted some new issue, I don't think it's quite worth all the extra typing.

 

I mean...healthy debate is good (and we all know I tend to either start them or perpetuate them to no end), but at this point, the debate it about old news.  I'm sure RSR or Ryan will say more about it at some point.

 

 

 

 

 

Had to smile when I read that Kyle was advocating tact.

 

 

haha - yeah...it felt a little odd as I was saying it.

 

I feel like I should defend myself a bit, but...eh...

[NovemberUniform 156]

Okay, let's wait for the update. Interesting discussion, though.

[777simmer 117]

I have not yet seen a "we will fix it or working on it response" from PMDG to our trimming problem.

Only from you Kyle, and only about the aircraft pitching up after AP disengage.

I probably missed it in between all the trying and typing, etc,

 

But good to know they are looking at everything and I will be quiet from now on.

[scandinavian13 5,192]

I have not yet seen a "we will fix it or working on it response" from PMDG to our trimming problem.

Only from you Kyle, and only about the aircraft pitching up after AP disengage.

I probably missed it in between all the trying and typing, etc,

 

But good to know they are looking at everything and I will be quiet from now on.

 

Well dang...for some reason I thought they had said something official.  I probably shouldn't have said anything without their official note of it first.

 

...and I'm not trying to quiet anyone.  Just saying that the discussion is becoming dated because it's discussing an old build.  By all means, I do think that some people could use a little more education on what the FBW is here to do.

[James Bennett 52]

By all means, I do think that some people could use a little more education on what the FBW is here to do.

 

I think PMDG should do a dummies guide to FBW implementation and use, just written in plain english explaining what the real aircraft does, why it does it, how it differs from other aircraft, and how that translates to it's useage and differences in the sim.

[scandinavian13 5,192]

I think PMDG should do a dummies guide to FBW implementation and use, just written in plain english explaining what the real aircraft does, why it does it, how it differs from other aircraft, and how that translates to it's useage and differences in the sim.

 

All I can think of is me doing a video tutorial like this guy (minus the fake, but hilarious melodrama):

 

"I know what you did!!!  I...Hey I saw it.  You went over to the clone stamp tool, didn't you?!?  Wrong!  St...Put it down!  We're gonna go...we're gonna go do it.  That's bush league and we're gonna do it this way..."

 

(Oddly enough, you actually learn some stuff in these videos.)