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PMDG 747 not trimming at the airbone??

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Guest Avenger

Hi folks... i`m need some help, may be anybody know issue for my problem..So very simple, I CAN`T CHANGE TRIM SETTING WHEN AIRCRAFT TAKEOFF AND CLIMBING!!!I`m prepeare fligh as wrote in many manuals for that craft. In the pre-takeoff preparation i`m tirm stab at 4 - 6 units. All normal, i`m use numlock key 1 and 7 and that works fine!But when i`m take off, gear up and climbing, i`m cant change trim settings anyways. The white bars in pedestal move slightly and jump at position was been before trimming. Of course at that stabilizer position i can`t continied my flight.First i`m think what that trouble at my joy Saitek X45, but at other crafts i`m never have that or some analogic problems. May be i`m somthing do it wrong?Please help me.Best regards AndyPS/ Sorry for my not good English.

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Guest D17S

PMDG, tell us about how "Autostab trim" is modeled in your 747-400. On the 747-1/200s there is a system that will automatically trim the stabalizer anytime an autopilot pitch mode is engaged. This is a very typical system for modern transports. It's clearly modeled into the PMDG airplane. On the 747-1/200s, if I pickle the stab (manually trim) when the AP is engaged, the AP will dis-engage. I see that is modeled in the -400 too. But just to prove the system is really there, I want to shut off stab hydraulics and get the "Autostab trim inop" message . . . but you didn't model the stab trim isolation switches, or even the alternate trim motors, or circuit breaker panels. We need the CB panels modeled (just that one Small thing, please!). (Let's see though, if I shut down 2/3 hydraulics, can I still get an AP? . . maybe that would do it. When we get through the this new fangled FMS based AFS, we're starting with the systems. Oh joy.) To get the airplane back into trim, an armchair pilot's best bet might be to just reengage the AP and let the AFS sort it out. If you are all out of whack, re-engage the AP and watch the stab drive back to where it needs to be. This modeling is very good. They really have done a great job.

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Guest Avenger

Hello... thanks for your answer.I`m small understood. If i takeoff at that 747-400 and NEVER turn on Autopilot, that system "Autostab trim" works anyways? Or at real plan that works only when in autopilot engage some pitch mode?I`m thinks that, be in true, but i`m can`t dream real liner, where real pilot can`t change trim settings at FULLY MANUALS flight? That`s can`t be in real, and at the PMDG plane that is reality?Best regardsAndy

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Guest D17S

You're very right. A pilot should be able to trim the stabalizer manually when the autopillot is disconnected. Actually, the pilot can trim anytime at all. If the autopilot is engaged and he trims, the autopilot will disconnect. This works in the model. I've tried to manually trim the stabalizer on the PMDG airplane before and I've always found the stab trim indicator to be very erratic. The indicator's movement is displayed very poorly in the model . . . but I've found the the stabalizer does trim normally. It appears this is just an 'indication' problem. As a test flight, I disengaged the AP by moving the stabalizer. I then moved the stabalizer so much that I lost control of the airplane. I could see the stabalizer trim position indicator jumping and jerking along as I manually trimmed the stabalizer. As I was falling out of the sky, I re-engaged the autopilot and watched the stab trim indicator. It hopped and skipped and generally acted very strangely. It was not smooth at all . . . but it (painfully) did move toward a more correct trim position. After many thousand feet, the airplane finally saved itself . . . with no thanks to me! I don't believe there is a system that will autotrim the stabalizer with the AP off . . but such a system could be something new on the 747-400. I don't see it in the PMDG model though. Really not sure there, but I doubt it.I think what you are seeing is a just poorly modeled stab trim indicator. . . but there's so much that is so good. I'll bet you think so too. PMDG, are we on the right track here?

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