PMDG 757 - Elevator Trim Question

[Guest jjlobo]

I'm studying 757 and didn't find in the manual any reference to Elevator Trim. It simply doesn

[Guest tonyc]

I don't understand. It works for me.tony

[Guest marcao]

Jo

[Roger Mazengarb 0]

G'day JJLobo,This is a repeat of a previous message that seems to have been lost in cyber space after the forum crash. Errrh "did I do that" :-eek :-eekYou are not going bonkers mate. Boeings DO NOT have elevator trim; at least not in the sense that one normally associates elevator trim.Boeing aircraft are aerodynamically quite nose heavy and require a substantial download on the horizontal stabilizer in order to maintain level flight. Longitudinal pitch trim is achieved by using a moveable stabilizer ( an inverted airfoil ). The elevators may be directly geared to the stabilizer so that they move a couple of degrees as the stabilizer moves but this is an automatic function and is done to ensure that full pitch control authority by the elevators is maintained over the full range of horizontal stabilizer movement. Check your manual under "stabilizer trim" for info on triming the B757. Better still load either the 707 or 747 by Jean Sabatier and you can actually see the horizontal stabilizer move as you trim the aircraft, :-) even get a take-off warning horn if the flaps and/or stabilizer are not correctly set for take-off.I don't have any pmdg aircraft so I don't know if they move the stabilizer or not but I would imagine that at least they would have coded the trim aerodynamic pitching moment if nothing else.Cheers,Roger @YSSY

[Guest jjlobo]

RogerThanks for the explanation. I found the problem related to one Hydraulic Pressure command still off. The trim started to work fine.The problem with it not working is that it was tough to keep nose situation in approach and climb stages. Near landing speed I was using full stick back to land. For climb I was using half stick back to keep situation.Now it is working smooth for climbing and landing.Thanks

[Guest jjlobo]

Marco Ant