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Do The B-787 & A-320 Have An "Auto Trim" System ?

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Hi,

I have a basic question that has me scratching my head since MSFS came out.  With all airplanes in the sim, when you push the trim switch that you have assigned on your hardware up or down, the airplane nose moves up or down accordingly and right away. However, with the B-787 & the A-320, when you press the switch, nothing seems to happen even though you can see the value change on the instrument panel. The only way to change the pitch is to push the Yoke or Side Stick to the desired pitch angle. At this point, when you let go of the Yoke, the plane will stay at that pitch angle''.......it's as if the Yoke is acting as the switch to trim the plane! Every other airplane, including the B-747-8 and Latitude, work normally-you push the trim button and the plane pitches accordingly.  Do the B-787 & A-320 have some sort of "Auto Trim" system, or something of that sort that make them different than other planes, and this is perfectly normal?

I would really appreciate it if someone could enlighten me on this.

Thanks in advance

Mario 

It should be, considering both planes have a Fly By Wire system in place

Chock 1.1: "The only thing that whines louder than a jet engine is a flight simmer."

 

The A320 trims to 1 g I believe automatically. I want to say it’s referred to as C* law.  Technically, I think that is supposed to blend g-load and pitch rate/stick deflection.  So it ends up at 1 g with hands off the stick, or largely the nose stays pointed where you left it. Thats all done by the FCC’s and under normal control law, trim doesn’t really change anything. 

 The 777, and I think the 787, trim to an airspeed. Which I think is C*U law. This is supposed to blend a feedback if you’re over or under trimmed airspeed. So if you “trim down” on airspeed, you would get a feedback to pitch up on the yoke and bleed speed. 

Eric Szczesniak

  • Author

Thanks for the explanation Eric, so, I guess that the way the plane is reacting, is actually true to life. I'm surprised that the B-747-8 doesn't react the same way, since it's just as modern......or maybe, MS just didn't model that function into the sim for the B747-8. Anyway, thanks again.

Mario

3 minutes ago, Marioalberto said:

. I'm surprised that the B-747-8 doesn't react the same way, since it's just as modern......or

AFAIK, the only fly-by-wire in the 747-8 are the spoilers and ailerons. 

EASA PPL SEPL + NQ / CB-IR in progress
MSFS24 | X-Plane 12 

 

even the smallest Piper has it now after SU7 update 😀, though we did not expect nor want it, I think they have changed it to default EASY mode presumably to make things easier for the beginner: Options - Assistance Options - Piloting - AI AutoTrim

AMD 7800X3D, Windows 11, Gigabyte X670 AORUS Elite AX Motherboard, 64GB DDR5 G.SKILL Trident Z5 NEO RGB (AMD Expo), RTX 4090,  Samsung 980 PRO M.2 NVMe SSD 2 TB PCIe 4.0, Samsung 980 PRO M.2 NVMe SSD 1 TB PCIe 4.0, 4K resolution 50" TV @60Hz, VR: Pimax Crystal Light + HP Reverb G2 @ 90 Hz, Honeycomb Bravo Throttle Quadrant, be quiet 1000W PSU, Noctua NH-U12S chromax.black air cooler.

60-130 fps. no CPU overclocking.

very nice.

Yep, called C* U in Boeing...

Flying gliders since 1980

Flightsimming since 1992

AMD Ryzen 5600x, 32GB RAM, GPU Nvidia RTX 3060 Ti 8 GB, 1 TB and 500 GB nvme2 SSD drives, HP 27" 60Hz LED monitor @ 1920x1080, T16000, Hotas from old X52 Pro, Saitek Combat Rudder Pro (2010 model)

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