Question about trim on final? 777

[scandinavian13 5,192]

 

 

Maybe I'm misunderstanding what Martin was saying, but the way I read what he said was that holding the yoke to maintain attitude would result in the plane automatically trimming for that attitude once the speed had stabilised, and pointed out that's not what auto-trim does.

 

I'll do some more research into the proper behavior, but aside from a few acknowledged little tweaks here and there, the team thought it was behaving as it should.

 

 

Kyle, my AP Disco alarm doesn't stop. This must be a bug.

 

<ducks>

 

Can't throw anything - laughing too hard...

[Flamin_Squirrel 71]

I'll do some more research into the proper behavior, but aside from a few acknowledged little tweaks here and there, the team thought it was behaving as it should.

 

No no, I think the PMDG 777 (aside from FSUIPC settings throwing up some strange behavious as previously mentioned) works perfectly.

 

The PMDG appears to follow the real things behavior: you set a trim speed with the trim switches. If you try to move away from this speed you'll have to apply a force to the yoke.

 

It's not all that different to a conventional plane, as any non-FBW plane will do a similar thing naturally. The 777 FBW just removes the influence of pitching moments from thrust/flaps/gear etc.

[scandinavian13 5,192]

 

 

No no, I think the PMDG 777 (aside from FSUIPC settings throwing up some strange behavious as previously mentioned) works perfectly.

 

Gotcha - I've been running through so many posts the last few days that I've just skimmed most of them, so I guess I misread what you were getting at.  Cool.  I was thinking I was going to have to chase down more info.

[icemarkom 59]

Kyle, my AP Disco alarm doesn't stop. This must be a bug.

 

<ducks>

 

 

Also, I can't seem to be able to get the WX radar to turn on. What a sim failure. ;-)

<running for cover>

 

Now, on a more serious note.

 

Reading through this thread (and not having read through all the manuals, but on the page 95 of FCTM), let me try to see if I understand the autotrim.

 

1) Just like in any other plane, once we've set the thrust and pitch, trim the plane. Trim is good.

2) Should we deploy landing gear and/or flaps, we don't need to re-trim, as the autotrim will take care of it.

3) Any other (thrust change/yoke movement) change will require re-trim, as in any other plane

 

Correct?

 

P.S. Autotrim is confusing me a little bit (and I can't blame FSUIPC, as I don't use it). I didn't even have a clue it was there until this thread, then I tried relying on what I thought it would do yesterday, but it wasn't doing what I thought it would do (magic). 

[hopskip 253]

 

1) Just like in any other plane, once we've set the thrust and pitch, trim the plane. Trim is good.

2) Should we deploy landing gear and/or flaps, we don't need to re-trim, as the autotrim will take care of it.

3) Any other (thrust change/yoke movement) change will require re-trim, as in any other plane

 

 

Thrust change shouldn't require a trim action from the pilot.

 

Significant speed changes might, but I'v just been holding it with yoke movement and then maybe touching the trim a tad after I have stabilized speed.

[icemarkom 59]

Thanks.

[ArjenVdv 190]

I've had some trouble as well. Banking seems easy but maintaining pitch - or actually maintaining a stable vertical speed - seems very very hard. Also I've noticed at 100 ft or so it's attempting to level off a bit. So for example I am decending at -750 ft/min it will try to level of at 100 ft to around -600 ft/min. I don't want it to do that, I want to have control over that myself.

[kamaz74 81]

Kyle, my AP Disco alarm doesn't stop. This must be a bug.

 

<ducks>

 

You have to hit the AP Disconnect button twice. Once to disconnect, and a second time to cancel the warning. You'll need to map 2 keys on your keyboard. One for the A/T Disco and the other for the AP Disco. 

 

EDIT, oh, were you joking? I look silly.  -_-

[lbarber 20]

You have to hit the AP Disconnect button twice. Once to disconnect, and a second time to cancel the warning. You'll need to map a 2 keys on your keyboard. One for the A/T Disco and the other for the AP Disco. 

 

EDIT, oh, were you joking? I look silly.  -_-

Then I'm supposed to do some 70's dance after I hit the Disco, right?

[Jerad 71]

It seems like everyone has MUCH to learn here about the new aircraft.


 

[kamaz74 81]

Then I'm supposed to do some 70's dance after I hit the Disco, right?

 

[Flamin_Squirrel 71]

Thrust change shouldn't require a trim action from the pilot.

 

Significant speed changes might, but I'v just been holding it with yoke movement and then maybe touching the trim a tad after I have stabilized speed.

The 777 will maintain the trimmed speed, and as you say, thrust won't change that. If you change thrust, that will cause the plane to speed up or down at its current attitude. Because the plane is trimmed to maintain a speed that it's now moving away from, it will either pitch up or down to get back to that speed, our you'll have to re trim for the new speed.

 

Hope that makes sense.

[martin-w 3,235]

Maybe I'm misunderstanding what Martin was saying, but the way I read what he said was that holding the yoke to maintain attitude would result in the plane automatically trimming for that attitude once the speed had stabilised, and pointed out that's not what auto-trim does.

 

 

 

 

 

Yep, that's precisely what I mean.

 

You can try it yourself. Fly straight and level at 250 knots or so. A/T on. Increase speed by 30 knots. The nose will rise as speed increases, which is normal. Now push your controller forward to maintain 0 vertical speed until the speed is stabilised, you will find the T7 in trim.

 

Would be nice if someone tested this in case it's just my set up. It's not a huge issue of course, but certainly not as real as it gets, unless I'm ignorant of how the T7 works.

 

Biggest issue is when you do trim. As speed increase [or decreases] you try to trim but nothing initially happens, so you trim again, and again. Then suddenly the pitch changes rapidly. It's as if there's a delay built in that shouldn't be there. Everything I've read about the T7 trim tells me that trimming for speed should feel no different to any aircraft, it should trim out the speed increase just the same. This doesn't impress me because handling is the most important aspect of the sim to me.

It seems like everyone has MUCH to learn here about the new aircraft.

 

 

 

 

To be honest, as far as trim is concerned, there shouldn't be anything to learn.

 

Speed increase should trim out like any aircraft. From what I know about the T7 anyway, and from what I've read in test flights.

[Flamin_Squirrel 71]

Yep, that's precisely what I mean.

 

You can try it yourself. Fly straight and level at 250 knots or so. A/T on. Increase speed by 30 knots. The nose will rise as speed increases, which is normal. Now push your controller forward to maintain 0 vertical speed until the speed is stabilised, you will find the T7 in trim.

 

Would be nice if someone tested this in case it's just my set up. It's not a huge issue of course, but certainly not as real as it gets, unless I'm ignorant of how the T7 works.

 

Biggest issue is when you do trim. As speed increase [or decreases] you try to trim but nothing initially happens, so you trim again, and again. Then suddenly the pitch changes rapidly. It's as if there's a delay built in that shouldn't be there. Everything I've read about the T7 trim tells me that trimming for speed should feel no different to any aircraft, it should trim out the speed increase just the same. This doesn't impress me because handling is the most important aspect of the sim to me.

 

To be honest, as far as trim is concerned, there shouldn't be anything to learn.

 

Speed increase should trim out like any aircraft. From what I know about the T7 anyway, and from what I've read in test flights.

 

I tested it, and it seems it DOES happen the way you describe. Maybe I misread the FCOM, not sure.

 

That said, you shouldn't have rapid trim changes, it's very stable. Have a look at your FSUIPC settings, it cause me a real headache.

[martin-w 3,235]

I tested it, and it seems it DOES happen the way you describe. Maybe I misread the FCOM, not sure.

 

That said, you shouldn't have rapid trim changes, it's very stable. Have a look at your FSUIPC settings, it cause me a real headache.

 

It's not like trim changes are rapid. More like non responsive, until several clicks. Then it suddenly trims and catches me out.

 

I don't use FSUIPC for my controller. Would FSUIPC still have an influence in that case?