Un-commanded inputs when trimming Mi-24

[Lixma 06]

I deleted the bug thread - hopefully it didn't cause any alarm.

I've started trimming by holding-moving-releasing and it's strange (e.g I normally fly Ka-50 with Flight Director on) but it does work well.

 

Edited October 21, 2024 by Lixma 06

[AeriaGloria]

7 hours ago, Lixma 06 said:

Even this doesn't cover it. Watch this video - After the first pitch down and trim I release the joystick; there is no further deflection; it remains centred. All I do is repeatedly press trim and the nose ratchets its way down. I then level off, trim, release joystick, and keep pressing trim button to 'walk' the nose up the ladder. 

 

As mentioned, your stick is too far forward. Yes you kept your stick still after the first trim, but that first trim was far forward enough that it kept touching down and AP couldn’t keep it level 

 

You need to stabilize it intended attitude, say -5 degrees for cruise, then trim 2-3x to even it out. That way you won’t have your stick too far forward.
 

I if you want to trim while pitching down at the same time, you have to also expect that your are giving enough forward stick to cause the pitch down in the first place, and move stick back while trimming. 
 

If you rapidly move collective in stable flight (which would rotate the elevator up and down, causing pitch), you will see that the 9% control authority of the pitch can’t stop very much movement. It is not like many modern airplanes where trim has 60-80% of the authority of your stick 

As your most recent post indicated, pressing trim and maneuvering also works. But I don’t prefer it. I have FFB so it’s different, but I like the dampening of the autopilot to smoothy my maneuvers, and the way it copies/exaggerates my inputs to give me more control during maneuvers. It’s all personal preference 

Note: you can see how it exaggerated/copies your stick by moving the cyclic on the ground with autopilot on and watching the indices follow your cyclic, or doing the same in active pause. In real life, this is how you check that AP works before you make sure that trim re aligns the attitude hold/cyclic copying 

6 hours ago, Lixma 06 said:

Speaking of trim release....

Here I am cruising and trimmed for level flight. The AP doesn't appear overly taxed.

Question: What happens when I hit 'Trim Reset'?

 

6 hours ago, admiki said:

Your nose will still drop a small amount since T channel is still slightly below neutral. It means AP is inputing nose up to keep your trimmed attitude.

Like I said, hold trim release until you are stable at attitude you want to keep. Once stable, let go of the trim and press it again and tell me what happens?

Yes I would say the AP is well aligned here. it It will never be perfect as it can be quite sensitive, you just want it near center, and eventually you will get a very good feel for it 

But what’s a bigger effect here then what Miki mentioned, if you were to press trim reset at this point, is your stick is trimmed behind center, which makes sense at 200 kmh. So trim reset will push your cyclic back to center, causing a pitch down.