Probably for the most expert it is a dumb question, but i couldn't find any information searching around.

Before takeoff, the trim, has to bet set to zero, and then set up during climb and cruise, or is there a kind of formula to set it up prior to the flight, based on cg of the aircraft?

On FBW a320 for example, MCDU tells how to set it up, but on GA aircrafts, how does it work?

Thanks

10 minutes ago, ConairMSFS said:

but on GA aircrafts, how does it work?

On all types I fly, there is a takeoff trim index marker which you align with actual trim setting.

Very easy. And from experience you 'll learn how to slightly modify the trim setting for takeoff. (Our C172SP at flaps 10, two persons on board, will at liftoff feel tail heavy with trim at the TO index marker, for example)

2 minutes ago, SAS443 said:

Very easy. And from experience you 'll learn how to slightly modify the trim setting for takeoff. (Our C172SP at flaps 10, two persons on board, will at liftoff feel tail heavy with trim at the TO index marker, for example)

Experience! That's what I'm missing. Still a lot to learn.

In real life I had some flights (152, arrow, and ultralights), but on the ground only taxi, no takeoffs. And never thought of asking about trim for takeoff.

Usually in sim yes, i set it at the center. But depending on fuel/cargo load, sometimes i have to compensate a lot with yoke, then i start messing with trim as soon as i climb, resulting in a not very smooth climb, or a guess how much to push or pull the yoke when i reach vr.

 

 

4 minutes ago, ConairMSFS said:

Experience! That's what I'm missing. Still a lot to learn.

In real life I had some flights (152, arrow, and ultralights), but on the ground only taxi, no takeoffs. And never thought of asking about trim for takeoff.

Usually in sim yes, i set it at the center. But depending on fuel/cargo load, sometimes i have to compensate a lot with yoke, then i start messing with trim as soon as i climb, resulting in a not very smooth climb, or a guess how much to push or pull the yoke when i reach vr.

 

 

Once you are off the ground, you adjust trim to take the pressure you have on the yoke to maintain the pitch or airspeed you want. If you are pulling back, adjust trim  nose up or towards you, if you a pushing forward on the yoke or joystick,  trim nose down or away from  you. It's adjusted perfectly when you can take your hand off the yoke or joystick, and it maintains the pitch you want. 

Edited March 4, 20233 yr by Bobsk8

The HJET trim shows green when set for takeoff.  Depends on the VSPEEDS and other factors .  Usually between 3 and 4 degrees.

sp

It is very aircraft dependant. Taildraggers for example are different to tricycle aircraft. Your weight and balance on the day can also have a big effect. Also whether you elect to take off wit no flaps on a long runway or use a notch or two to effect a short field take-off. There is no standard rule you can apply to every situation in every aircraft.