Nealius Posted March 26 Posted March 26 (edited) I keep having an issue where the FTR doesn't seem to set the trim and the stick returns to an aft position, forcing the nose up when it should stay where it was when I released the FTR. After a few hits of trim reset and mashing AFCS down trim I can resolve it but I have no idea why it's happening. It only seems to happen when I have troops embarked and I use the AFCS pitch trim to fine tune my attitude. Can someone review the replay track and see what's going on? Afghanistan map, no mods. Pitch mania starts right after embarking troops from a riverside LZ. Big file and WeTransfer appears to be dead so here's a Google Drive link: https://drive.google.com/file/d/1jySIes5KG1Htw6lt014BX39YvW8gTs6g/view?usp=sharing Edited March 26 by Nealius
Stu6711 Posted April 3 Posted April 3 Not just you, however I'm very surprised nobody else has brought this up. This affects everybody who flies the Chinook in my virtual squadron. Force trim worked beautifully when ED introduced LCT & DASH on update 2.9.9.2280, and we could finally fly her straight and level. However, after update 2.9.11.4686 when ED introduced CD REL (replacing force trim), this is where this bug was introduced. You get her flying straight and level, press the CD REL button, release then she begins immediately gaining altitude rather than remaining straight and level how she did after 2.9.9.2280. It's very annoying.
Cyborg71 Posted April 3 Posted April 3 As you are searching for others..... Same here, I've observed pitching moments both nose up and down after trim is 'set'. In my case bump trim does not resolve it. The problem is exacerbated by speed above 130, where porpoising requires frequent heavy fore and aft cyclic inputs to fight rapid uncommanded descent or climb. I'm sure this behaviour is abnormal.
Marsvinet Posted April 4 Posted April 4 I can't say I've experienced the pitch up the way you describe it, but what I've seen feels connected. For me the AFCS appears to overcorrect any small movements in the pitch axis, so if you make a small correction aft, the nose shoots up way further than the stick movement should warrant, but after about a second, it has dropped back down to where the correction should have ended up. I notice it most in a hover, where I constantly jerk the stick back and forth to quickly get rid of the AFCS overcorrection, I can easily see how it could cause some big effects at higher speeds. I know this has to be incorrect, because when the 1970's analogue Mi-8 autopilot does a better job at stabilizing than the 2000's digital beast of the DAFCS, it can't be correct. But I guess we'll just have to wait, WIP and all.
Cyborg71 Posted April 4 Posted April 4 I should have also mentioned that I have checked and re-checked my control bindings, axis, for conflicts, oversensitive settings etc. It definitely feels like a fight currently. I may (unusually for me) have to sit back from the hook for a while, until a fix or two resolves the 'cruising' instability. It would be great if one of the sme's or an irl Chinook F pilot could offer some insight. There's every chance I'm doing it wrong.
Nealius Posted April 5 Author Posted April 5 It should be noted there are two different types of pitch-up movements being discussed here. The first, and the main point of my discussion, is the aircraft refusing to update stick position after releasing CD REL, causing the aircraft to violently pitch up because there's still aft stick input when there shouldn't be. In other words, the rotors are pitching. The second, which others have been commenting on, is when the stick position is updated after releasing CD REL, but the aircraft attitude gently pitches up causing a climb. In other words, the rotors are not pitching, the aircraft body is pitching via the LCT/DASH magic and causing an ascent. I've attributed the second issue to WIP LCT/DASH etc. dynamics. The first, and primary issue, however, seems to be more of a bug. 2
av8orDave Posted April 5 Posted April 5 I just flew the 47 for the first time in a bit. If the CD REL trim command is working, I can’t tell. It seems to have no effect. Very annoying. 1
Cyborg71 Posted April 5 Posted April 5 18 hours ago, Nealius said: It should be noted there are two different types of pitch-up movements being discussed here Apologies, it wasn't intended as a thread hi-jack. I've experienced both issues. I will re-visit the violent pitch up you describe, though I'd put that down to my choice of instant trim, sprung joystick. The circumstance I mention happens when level flight is demanded. Within a few seconds of setting a speed/attitude and altitude, a nose down or up occurs. I guess you could call it gentle. Maybe I'm trying to cruise too fast. I'd not considered the LCT/DASH as part of the potential cause. Thanks. 1
Stu6711 Posted April 6 Posted April 6 (edited) I also tested using a FFB stick. So the issue isn’t specific to CD REL, as you’re technically not required to trim with a FFB stick. I’ll get her straight & level, then let go of the stick (as it’s a FFB, the stick stays in the exact same position it’s been left in) & she’ll begin to climb. So it happens after trimming with CD REL, and it also occurs using a FFB stick without trimming using CD REL. Edited April 8 by Stu6711
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