Hi, I’m completely new to the community; this is my first post. I’ve wondered if anyone’s had an issue with some aircraft requiring a slight negative pitch to maintain level flight, in particular at higher speeds (flaps retracted)? The TBM is one such aircraft, but there are others.
Hey! You’ll want to use trim to fix this. If the aircraft is pitching up a lot, use negative trim to help push the nose down.
Here’s a few helpful resources regarding the use of trim:
Hey there! Welcome to the community. To answer your question, this is common among specific aircraft(s) and like @lucaviness, trim is the best way to fix this.
If you have any other questions, feel free to create a topic or PM me. Stay safe!
Does this refer to cruising speed? If so, then you may want to slow down. Otherwise sometimes aircraft tend to pitch down when descending and adjusting flaps
Welcome to the community, @adit! If you have any questions please don’t hesitate to ask!
Now if you’re flying one of the older aircraft in the IF fleet, it naturally pitches down a bit (especially the 757). This is because the aircraft need full rework, which will help with this nose-down autopilot.
Now if you’re flying any of the newer aircraft in the fleet, you’ll need to use trim. Like mentioned above. Also, if you’re using too much flap or are going too fast, and are trying to descend, then your aircraft will pitch down more than necessary.
Thanks so much for the reply. The pitch down required to keep the aircraft at a constant altitude happens independent of trim. So independent of whether there is “yoke pressure” (needs trim) or yoke neutral (fully trimmed for flight configuration) the same amount of slight pitch down (for now climb) occurs at the given airspeed. You can see it by the nose level mark having to be below the horizon mark, to keep the flight path vector pegged on the horizon (zero vertical speed). Externally the aircraft also is seen as slightly pitch down, which looks unusual I was thinking (maybe I’m wrong?).
Hmm… it’s possible your airspeed is too high. You can utilize a simple Google search for an aircraft’s appropriate cruise speed. Do you remember what airspeed you were at and which aircraft you were in at a time this happened?
You mentioned the TBM above. Its cruising speed is roughly 330kts. Do you think you were around that speed?
Yes, what Luca said. And that would be in ground speed. For higher altitudes that would be an airspeed of about 180kts.
Oh yes, thanks for reminding me, the 757 is where I had also really noticed this effect. The TBM is of course newer.
Good question. So I was just trying with the autopilot on, set a zero vertical speed (at 17,000) It seems that the autopilot needs to start some slight down pitch starting somewhere after 190knts to keep from climbing, so the flight model seems to require that down pitch well below cruise speed? It’s not like 5 degrees down, a couple of degrees, if even that, at maximum cruise maybe. I just wondered if I was missing something. Are any aircraft designed to have some slight pitch down for approaching cruise speed? I just had always assumed always slight positive angle of attack means the nose is also angled slightly above horizontal for level light, depending on speed and weight.
Okay, I’m not sure of the reason. If it continues to be a concern, I’d consider uploading a replay so the devs can see if it they can recreate it and either tell you what to different or fix an outstanding issue. Hope this helps!
Thanks so much for the welcome!. And for confirming some other aircraft have this issue. I assume it has no device dependence (android in my case). It seems it might be a flight model quirk. Most of the flight model characteristics in IF I find realistic and immersive. But when I look at the aircraft nose down slightly in level flight, it takes away a bit of the reality. It’s more a question of high fidelity I guess, not at all about being unflyable.
I was looking at a flight history website with a graph of angle of attack vs speed for level flight. Above stall speed the angle for level flight drops quickly and then starts to flat line at higher speeds to a few degrees above the horizon. But the angle, at least in that example, was always more than zero…I’m probably overthinking it!
Thanks for your reply. I guess my question would be: Does anyone know if there is a general knowledge of a flight model quirk - an angle of attack saturation vs speed issue? Incidentally, I love the overall flight model!
This issue isn’t device dependent. Personally, I have yet to notice this on the TBM (may be to the lack of times I have flown it), however like others have mentioned, it’s prominent on older, non reworked aircrafts such as the 757.
I do agree that such issue affects the realism of the simulator, however as far as I’m concerned, this isn’t such a huge issue as it can be resolved by using trim.
Thanks you. Yes it was the TBM and I checked that it started just above 190knt (IAS, 17000ft), and the negative angle grows with speed then seems to stop, or saturate at a particular negative angle. (haven’t tried going way beyond redline to see what happens!)
Yeah I guess the device dependence doesn’t make much sense. I also agree it’s not huge, but something for the wish list perhaps. Actually a bit higher on my wish list than for other perhaps.
If I recall correctly, this isn’t the first time this issue has been brought up so it’s most likely been noted by the devs (don’t quote me on that). I also suspect, based on previous reworks, that as older planes are reworked such as the 757, their physics will be improved and this issue will be resolved. I do apologize that this is causing you distress and hopefully it’ll be taken care of soon!
I do appreciate your comments. Also, the distress would be my mind’s eye seeing the oncoming relative wind hitting the top of the wing! (with negative pitch) But then I think of the new VNAV, new procedures, global flight, and on an on, and there is a lot more to be thankful for!
Thank you for your reply. It starts even before cruise speeds.