I see mention sometimes in some aircraft files that 'aircraft is pre-trimmed' for take off? How is that done? I'd like to be able to have my trim already set but I would think this would have to do with fuel load and payload and that it would change from flight to flight. Can someone explain 'pre-trim' and how it's done? Thanks

I see mention sometimes in some aircraft files that 'aircraft is pre-trimmed' for take off? How is that done? I'd like to be able to have my trim already set but I would think this would have to do with fuel load and payload and that it would change from flight to flight. Can someone explain 'pre-trim' and how it's done? Thanks

Depends on the aircraft. Some aircraft have fixed takeoff trim position for all takeoffs, and on others the takeoff trim varies on aircraft CG/weight and performance. On aircraft where it is the same for all takeoffs, you set the trim to that spot before takeoff (either with a trim wheel, electric trim, etc.) For aircraft with a fixed takeoff trim position, there should be a marking of some sort on the trim wheel or trim indicator to show you where this point is.For aircraft such as airliners, takeoff trim varies and is set based on takeoff conditions, and CG/weight. An FMC will usually tell you what the takeoff trim should be set to before takeoff or other performance charts should be used.

As the poster before me said, most light planes such as your Cessnas and Pipers 4-6 place planes just have a marker that says "TAKE-OFF" and you set the trim indicator there. For larger jets, it's usually the FMC or something listed in the aircraft's POH. I know both the PMDG 737NG and the FT 737PIC show the trim setting on the TAKEOFF page of the FMC.