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z06z33

Question about trim on final? 777

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All the approaches I've made in the 777 have been a struggle. I can't keep the nose down while on final I trim it to where I need it, get it on the GS then the nose starts to rise even when I mantain the same airspeed or slow down. It's like there is a little gremlin in there and when he sees I'm nailed on the GS he decides to hit the up trim. I had to push the yoke most of the way forward to get the plane to respond. It's not a hardware issue as the yoke works great with the NGX ect. Any thoughts?

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I've had some strange control issues too, where as the NGX seems fine also. Something else I noticed was the yoke doesn't move in the VC. This makes me wonder if something' not installed quite right?

 

Do you have this same issue? I'll do some more research tonight.

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Auto trim...

 

I've said it a bunch here, but I'll repeat it here:

The 777 is not the 737.  Do not treat it like one or it will bite you.  This is a different bird and as I said before the release, those of you with time in the NGX will probably almost be at a disadvantage because you'll come at it with a sophomoric "oh, I know Boeing" approach.

 

There are a bunch of autotrim threads here in the forum.  There's also one on a.net, which I don't think we can link to here, so I'm using LMGTFY (but not to be a jerk for once - just to allow me to post a link for you):

 

http://lmgtfy.com/?q=777+autotrim

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so I'm using LMGTFY

LOL......I loved this little shortcut. I have never seen it before. But yes, you are correct, Google is the modern up to date on line encyclopedia about every and any thing that we need to always try before simply asking here.

Regards 

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I made a post about this. My first landing on the T7 was terrible because I thought it would handle like a big NGX. Boy was I wrong. It is an entirely different plane.

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Auto trim...

 

I've said it a bunch here, but I'll repeat it here:

The 777 is not the 737.  Do not treat it like one or it will bite you.  This is a different bird and as I said before the release, those of you with time in the NGX will probably almost be at a disadvantage because you'll come at it with a sophomoric "oh, I know Boeing" approach.

 

There are a bunch of autotrim threads here in the forum.  There's also one on a.net, which I don't think we can link to here, so I'm using LMGTFY (but not to be a jerk for once - just to allow me to post a link for you):

 

http://lmgtfy.com/?q=777+autotrim

 

Ok I've done some more testing. I think there's too much strangeness going on to simply be my own incompetence. I knew about auto-trim, but I'll describe what's happening, just in case.

 

The first thing I tried was to disconnect the primary flight computers to eliminate auto-trim as a variable. Some things I noticed In direct flight mode: the flaperons oscillate at about 2Hz (both on EICAS and external view). Visually, the elevators are frozen in the neutral position (both on EICAS and external view), while pitch control is maintained (in fact, controllability seems better than normal flight mode).

 

Now normal flight mode: when I pull up for example, I see the elevators move up, then return to their previous location. I pull back further, again returning back to the same position. I know auto-trim is active, but this all happens rapidly, before any change in airspeed occurs. This makes pitch control very difficult as the elevators always reset their position.

 

Oh, and the yoke is also frozen (fore/aft, the wheel rotates still) in the VC, in both normal and direct mode. It simply doesn't budge, whatever I do.

 

I know this isn't a 737, but how do you find maintaining an accurate approach, compared to the NGX?

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I had a similar problem with the NGX using my Saitek yoke. I found that I had the elevator and aileron axis set in both FSX and FSUIPC. Hope that helps.

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I had a similar problem with the NGX using my Saitek yoke. I found that I had the elevator and aileron axis set in both FSX and FSUIPC. Hope that helps.

 

A controller issue was my first suspicion too, but It's not that; the NGX flies fine.

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Ok, I managed to solve my issue at least. I had my elevators assigned in FSUIPC as a normal FS axis. Apparently while the NGX is happy with this, the 777 doesn't like it.

 

Anywhoo, sending control direct to FSUIPC solved the problem for me.

 

...oh, and now it flies absolutely brilliantly!

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I made a post about this. My first landing on the T7 was terrible because I thought it would handle like a big NGX. Boy was I wrong. It is an entirely different plane.

 

That's really funny, as on my first flight (a familiar KSFO-KLAX) that's exactly how I treated it and did full visual (I know Kyle is reading, so I can't use the M-word) landing with no issues. Only then did I go to read the tutorial and did things the right way. I can't wait for the wife and kid to go to sleep tonight to give it another spin :-)

 

It's a fun bird to fly, for sure :-)

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(I know Kyle is reading, so I can't use the M-word)

 

After reading the FCOM and seeing that Boeing used it, I've since given up  :P

 

...but yes, I'm always watching  :ph34r:

haha

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Auto trim makes the 777 awkward to control on final... Not sure if it was implemented improperly or if FSX doesn't play nice with auto trim. 

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Auto trim makes the 777 awkward to control on final... Not sure if it was implemented improperly or if FSX doesn't play nice with auto trim.

Those were my initial thoughts for a split second; then I remembered this is PMDG we're talking about so of course it's done properly. If you use paid for FSUIPC, make sure you let it handle the control inputs, it doesn't work properly otherwise (at least for me).

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Those were my initial thoughts for a split second; then I remembered this is PMDG we're talking about so of course it's done properly. If you use paid for FSUIPC, make sure you let it handle the control inputs, it doesn't work properly otherwise (at least for me).

 

Make sure you let FSUIPC handle the control inputs?

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Make sure you let FSUIPC handle the control inputs?

 

Yeah. Do you have paid for FSUIPC? If you do, take a look at the image below. I made sure i checked the option (circled). If I try using the one below, it goes crazy with the 777, but is fine with everything else.

 

pq6g.png

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Yeah. Do you have paid for FSUIPC? If you do, take a look at the image below. I made sure i checked the option (circled). If I try using the one below, it goes crazy with the 777, but is fine with everything else.

 

pq6g.png

 

I do have a paid copy. Good deal, thanks!  ^_^

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I do have a paid copy. Good deal, thanks!  ^_^

 

No worries. Let me know if it makes a difference; I wonder how many people are struggling to fly without knowing there's a problem!

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guys autotrim works fine in fsx. Just try not to touch the trim at all... Set the trim for takeoff and thats it. 

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guys autotrim works fine in fsx. Just try not to touch the trim at all... Set the trim for takeoff and thats it. 

 

Yes the trim does seem to work that way.

 

In reality, trim changes aren't required for configuration changes in the T7, for example flap deployment or thrust increases and thus a pitch up due to the fact that the engines are below the wings.

 

However, Boeing designed the T7 so that trim is required for as speed increases. My test flight today demonstrated that this is working correctly, but the trim response could be better. Perhaps that's related to my hardware.

 

However, like you, I have noticed that it's also p[possible to not trim at all with speed changes, and simply push the yoke forward or back to maintain level flight. Once the speed has settled, it's in trim. No idea if that's as per the real aircraft, but it certainly makes life easier not having to trim.

 

Banking seems good, as per the real aircraft, it remains at the desired altitude without back pressure on the yoke, as long as it's not in excess of 20 degrees.

 

I did notice though that there is a considerable tendency to float if auto thrust is left on for landing. I know this is done in the T7, but it's not a good idea in the sim it seems. Could be that the thrust is not back to idle soon enough.

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guys autotrim works fine in fsx. Just try not to touch the trim at all... Set the trim for takeoff and thats it. 

 

That's true for an Airbus but not for the 777. You have to trim with speed changes.

 

However, like you, I have noticed that it's also p[possible to not trim at all with speed changes, and simply push the yoke forward or back to maintain level flight. Once the speed has settled, it's in trim. No idea if that's as per the real aircraft, but it certainly makes life easier not having to trim.

 

That's not how the real plane works, no.

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I flew my companiy's T7 simulator for 2 hours in February this year and can attest that I had to work the trim quite a bit throughout all phases of flight. The only part of the airplane that I did not have to manipulate much at all was the rudder...only for takeoff roll and landing roll-out. The T7 definitely needs a healthy exercise of the trim.

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That's not how the real plane works, no.

 

Mind explaining how you think it works?

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Mind explaining how you think it works?

 

I have to say, I see where he's coming from.

 

It is possible it seems to not bother to trim for speed changes, and just maintain altitude with the yoke. As soon as the new speed is stabilised it then stays in trim.

 

Is this normal behaviour for a T7 Kyle? The research I did this morning didn't reveal this behaviour.

 

As far as I know, it is always necessary to trim as speed increases or decreases. 

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I'm a bit flummoxed by autotrim as well, I've had a hard time getting it to do what I want. Does the FBW change trim (or reference speed) in response to column inputs too?

 

It seems like when I give column input the airplane seems to start to run out of elevator authority (e.g. the nose stops pitching). When I release that input the airplane feels like it retrims itself and I can add the same column input and the airplane will respond more along the lines of what I would expect. I experienced this with a very light load shooting touch and go's at MWH.

 

If I want to reduce airspeed in level flight I should just reduce thrust and not touch the trim, or should I reduce thrust and hit the trim switches?

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