He111 and course autopilot problem

[F/JG300_Gruber]

Hi everybody,


I have a problem with the course mode on autopilot, it just doesn't want to keep the two scales matching on the gyro.

Even starting on level flight,

What I am doing :

Elevator trimmed (either level flight or climbing)
Ball centered via rudder trim
ailerons trimmed to keep wings horizontal
Gyrocompass adjusted to match the repeater compass
autopilot course scale matching the gyro scale
Autopilot engaged

And then each time the plane just bank (left usually) and change course by 4-5°, sometimes more and then stabilize its course. Wings not always parallel to the horizon.


What the frak am I missing there ? :S

[ATAG_Lolsav]

To be more precise, you talking about "mode 22" ?

The plane will dive to gain speed (around 400kms) and then slowly level out, gaining a few meters from the drop. From my experience you lose around 800 to 600 meters on altitude once mode 22 is enabled. Trim the nose all the way up after enabling that mode to help the plane to regain altitude. And do it around 2-3 grids out of the target. Final corrections can be made in the bomsight, adjusting course right/left.

[F/JG300_Gruber]

To be more precise, you talking about "mode 22" ?

The plane will dive to gain speed (around 400kms) and then slowly level out, gaining a few meters from the drop. From my experience you lose around 800 to 600 meters on altitude once mode 22 is enabled. Trim the nose all the way up after enabling that mode to help the plane to regain altitude. And do it around 2-3 grids out of the target. Final corrections can be made in the bomsight, adjusting course right/left.


Not at all :D


I'm talking about the first mode (course mode)
When I need to get the plane going to let's say course 270, it will go to something like course 265

Even when propery trimming the plane on the 3 axis to follow this course (repeater compass and gyro showing both 270, autopilot setting matching the 270 on the gyro), when I engage the course mode, the plane will bank and then settle to something else, usually 4 to 6 degrees off course.

[InvaderZim]

In "course autopilot" mode you will aways have some drift, even when trimmed. Thats normal, You have to re-trim and recorrect course using the "course scale" AP and trim once it on course. You may also have to continue with minor course adjustments using course scale as you go. This also upsets the trim and causes you to retrim. Its not like mode 22. You probably already know that.

I usually come to course, set "course autopilot" and just fly by trim, course scale, and terrain association from that point on untill its time to go mode 22.

[F/JG300_Gruber]

Thanks for the reply,

For the trim I understand, I've seen that I have to re-trim a little bit after the autopilot is engaged.



Just a few pictures to illustrate what I mean :


Here the autopilot course mode is active and the plane has been in stable flight for a few minutes before I took the screenshot. Wings are leveled, ball almost centered but the gyro scale and the course preset scale are not matching, there is here 4° difference between them (and the "Kurs" indicator isn't centered either)

http://i155.photobucket.com/albums/s299/nono-des-montagnes/IL2%20Sturmovik/course2.png


If I want the autopilot to fly with the two scales matching, I have to put it in this position with aileron trim. (again this is has been stable for a few minutes before screenshot) :

http://i155.photobucket.com/albums/s299/nono-des-montagnes/IL2%20Sturmovik/course1.png




So is this a normal situation for everybody that the autopilot keeps the plane off course ?

[1lokos]

No, this "mismatch" in Kurs indicator is "normal" - instrument feature or bug it was since release.

See Blackdog_KT post about Autopilot on 1cforum http://forum.1cpublishing.eu/showpost.php?p=313221&postcount=1



4) You should now have a calibrated DG. Now use the course AP left/right controls to match the desired heading to the DG, so that when you engage the AP it won't start banking like mad.

There's an important note here and i don't know if it's a bug or a realistic feature: the desired heading and the DG compass cards are not completely aligned, they have a 5-7 degrees offset.
So, if you are flying due north and set both to 0 degrees, instead of flying straight like expected the bomber will slightly bank left and right, finally settling on a heading between 5 and 7 degrees off (heading specified by the DG not the magnetic compass).

To correct for this you can apply a correctional offset yourself. In the below schematic the top row is the DG compass card and the bottom row is the desired heading compass card that the AP will try to achieve, it should look like this:
---N---
------N---




BTW - Blackdog_Kt = Buzzsaw? :D

The first appear in Bananas and vanished more that Luthier after CloD official "finish", and the second don't exist in Bananas. :whacky4:

[F/JG300_Gruber]

OK so it is known, and "normal".

thanks :)

[LuseKofte]

What I read about the autopilot was from the Russian front Late war, it was mentioned as non reliable and if used you needed to have hands on yoke to help it

https://www.youtube.com/watch?v=EEot-4ELnQo