Hello,
I've just tried Stabs4All with a pair of random planes, and it works fine.
I'm thinking of two possible causes to your problem:
1.- You must activate the mod Stabs4All through JGSME program before launching IL-2.
2.- You have mapped the key for 'Toggle Level Autopilot' instead of 'Level Stabilizer'.
I bet for the second cause, because in fact it is a bit confusing. It was explained before by creature in his reply #962:
https://www.sas1946.com/main/index.php/topic,44975.msg507022.html#msg507022In short: 'Toggle Level Autopilot' does NOT activate level autopilot. It has a rather confusing name. In fact, it only toggles the behaviour of autopilot. I've found it to be useful in biplanes with a rear gunner, when trying to shoot down balloons. Usually, by pressing 'C' (default key) you can change between pilot and gunner, but if Pilot Automation is ON, when you press 'C' to go to gunner position, the pilot is set automatically in autopilot mode, making it very difficult to aim for the balloon. However, if you previously de-activate Pilot Automation by means of 'Toggle Level Autopilot' key, you can change to gunner position without loosing control of the pilot. Thus, you can still control the plane with your joystick, and aim the gun with the mouse. Tricky, but the low speed of biplanes make it easier than letting the plane control to the computer.
If you want to set a real level autopilot, you have to bind a key to 'Level Stabilizer', which you can find rather at the beginning of the command list; I use 'Alt + A'. I've tried tonight and it works: when you press the corresponding key, the plane corrects the current positions of yaw and bank, and keeps a level flight. You cannot control the plane anymore until 'Level Stabilizer' is set off again.
Try and tell if it still doesn't work