On speed trimming for what?

[nicesub]

Hi,

As I am trying to learn how to land the plane I keep hearing fly it on speed (yellow circle) and trim. 

My question is what do you mean trim? Trim for what? So that the plane flies level when on the yellow circle no matter what or for some specific descent rate or what? What I need to target with the trim? Confused with this as everyone keep throwing this word trim but never specify desired effect to be chased with it.

[razo+r]

In general, when someone says trim the plane, it means that you have to trim it in such a way, that there are no forces on the stick, basically the aircraft remains in a fixed attitude at a specified speed.

When someone says trim on speed, it means you have to trim it in such a way, that your aircraft maintains the perfect AoA for landing, indicated by the yellow circle.

And as it is the AoA for landing, you should be in a landing configuration. But if you do it in level flight or on the standard 3 degree glide is up to you. You just have to trim it in such a way that the aircraft maintains the on speed AoA. The trim is mostly the same, regardless if you are in a descent, level flight or climb as long as you maintain the speed. Trim changes with speed, so once you are on speed, you shouldn't have to touch trim anymore until touchdown if trimmed perfectly.

Quote

Confused with this as everyone keep throwing this word trim but never specify desired effect to be chased with it.

Trim is one of the very basics of aircraft. You can easily find hundreds of thousands of ressources online about what trim is.

Here's an example:

https://pilotinstitute.com/aircraft-trim-explained/

Edited 21 hours ago by razo+r

[nicesub]

But if I trim for the cat to fly level whilst at the yellow circle, how the hell it will descend to land if all is fixed in place?

[razo+r]

6 minutes ago, nicesub said:

But if I trim for the cat to fly level whilst at the yellow circle, how the hell it will descend to land if all is fixed in place?

You reduce power, which in turn will slow you down, less lift, nose goes down, aircraft starts to descend. If you increase power, the aircraft will start to climb.

Or you use the elevators to pitch down and reduce the power a bit so you don't pitch up again.

Edited 20 hours ago by razo+r

[RustBelt]

In landing you pitch (trim) for speed, and use power for climb descent. With a spring centered joystick trim is hard to understand. You’re using the stick to hold the nose at your desired AoA (and so speed) in a real plane or with Force Feedback, you then trim until you don’t have to hold the stick where you put it. You’re moving the neutral point of the stick.

With a spring centered joystick it becomes unintuitive, as you trim you’re bringing the stick back to its centering point to emulate trimming off forces. So the stick position changes as opposed to the stick staying where it is and force against keeping it there trims away. 

[Q3ark]

9 hours ago, nicesub said:

But if I trim for the cat to fly level whilst at the yellow circle, how the hell it will descend to land if all is fixed in place?

When you’re on finals and you’re all nicely trimmed out use power to adjust your glide slope.