Trim...

[SwingWingDriver]

Hello pilots, I have a question regarding trim and I cant seem to find the answer so here's the question.

I see a lot of videos etc that mention setting trim when you get to altitude to fly level, in formation or A2A refuel. I have the trim setup for all my planes to the trim hat on the WinWing Orion F15EX stick. No matter how I set the trim, it never stays level, it either starts nosing up or nosing down. Even when I tap for microseconds to just ever so barely nudge the hat to try to get a decent balance it simply never works without nosing up or down within a few seconds. When I have it set, I still have to make a lot of manual adjustments in the opposite direction just to keep it balanced. I have spent entire 45 minute flights trying to see if I could get a plane trimmed properly but it always favors one way or another. Is this the norm or an I missing some basic or advanced concept?

 

P.S Altitude hold in autopilot works frickin great, but using the trim hat not so much

 

Thanks!

[Hiob]

Unfortunately this is the state in most aircraft. The trim increments are just not fine enough to get it perfectly balanced. 

However, I suppose it is similar in real aircraft. Trim is meant to relief the holding forces on the controls for a given attitude - not to fly hands off for a prolonged time. That is what Autopilot is for. 

But being properly trimmed gives you the convenience of doing very minuscule corrections with the „fingertips“.

That‘s just my take on the matter. I‘m by no means an expert - let alone a real pilot.

[Bananabrai]

8 hours ago, SwingWingDriver said:

[...] I still have to make a lot of manual adjustments in the opposite direction just to keep it balanced. I have spent entire 45 minute flights trying to see if I could get a plane trimmed properly but it always favors one way or another. Is this the norm or an I missing some basic or advanced concept?

[...]

Thanks!

It's the norm. Every real aircraft behaves differently with trim. Some have big increments, some you can trim very fine

8 hours ago, Hiob said:

Unfortunately this is the state in most aircraft. The trim increments are just not fine enough to get it perfectly balanced. 

However, I suppose it is similar in real aircraft. Trim is meant to relief the holding forces on the controls for a given attitude - not to fly hands off for a prolonged time. That is what Autopilot is for. 

But being properly trimmed gives you the convenience of doing very minuscule corrections with the „fingertips“.

That‘s just my take on the matter. I‘m by no means an expert - let alone a real pilot.

This is indeed how real aircraft behave.
Trim is not meant to reduce control forces of a given attitude (that would be an ATT - HOLD mode), this is substantially wrong and is exactly what I can the in the sim community as expectation - use trim to level of perfectly.

However, the massive difference is: trim neutrals control forces for a given aerodynamic state.
The aerodynamic state changes with every little fragment of a knot, with every fragment of a degree of bank or yaw, etc. The slightest input or force changes this balance, and there you go, the trim is not correct any more. Not fundamentally, but it just wants into a slightly different state.
If your speed and bank is constant however, in a modern jet with a very fine trim, like the Hornet, it should be fairly stable. The Viper is a different story.

This behaviour is best observable in small aircraft (that's why I am a fan of very basic flight training and not starting of in a Hornet or something fancy)
You set a certain trim, forces are almost gone, and you let go of the stick/yoke. The aircraft will make small changes again and again, around this perfect state the trim dictates.
Basically it will oscillate around this state very smoothly, given near perfect conditions and roll stable.

[Hiob]

@Bananabrai Thanks for the correction.  I guess missing real forces on the stick as a desk pilot makes it a bit harder to wrap your head around - for me at least.

[Bananabrai]

One of the things that are harder in the Sim than IRL. We are missing the feeling in the sim, the haptic and everything you get back from the AC.