Preset for Trims

[Shahriar0]

Hi,

I would like to know how I can define presets for various trims (aileron specifically) in DCS that would apply either to all planes, or on a per-plane basis.

This question has come about as a result of a peculiar problem I have with a certain HOTAS, the Logitech X52. Apparently newer products have a tendency to drift to right! This became apparent when a couple of years ago, a DCS buddy of mine bought his new X52 and noticed this right-drifting tendency. He went through exchanging several units before realizing all displayed the same behavior/problem. Meanwhile, my own X52 that was bought in the 2000s shows no such problem. It flies straight when there is no input from stick. Yesterday when I received my new unit (as backup), I immediately saw the same exact characteristic.

Apart from contacting Logitech (which was done a couple of years ago by my friend, with the ultimate result of the ticket remaining unsolved and all emails unanswered!!), my solution is use left aileron trim to compensate for this drift. This works, but obviously, I don't want to spend anything between 5-15 seconds of every single flight I am going to conduct to trim for a straight flight. Please note that, trimming takes a bit of time. After an input, you need to observe the result and see if trim was enough or was overdone, etc. Best solution in my opinion is to use preset for aileron and find a value that compensates for the right drift for this particular HOTAS.

I have searched the forum and tried all the various suggestions to no avail. That includes the most obvious one to add aileronTrimTab = <value> to various files such as FMOptions.lua file. Unfortunately none has worked. What I need to know is the exact syntax of the command, if different, and the location of file (per DCS or per-plane) to include.

Also I would like to rule out other things that do contribute to a drift, such as rudder not being dead-center, uneven fuel, unbalanced plane balance due to dropped ordnance, impact of defined dead zones, etc. To add that X52 has no calibration of its own. It re-centers itself after every boot. When I use my old X52, I can take any plane and fly straight with no problem. I disconnect and put the brand new X52 and in every plane it shows the exact right drift by the same amount (it 30 seconds, the plane is banking a good 10 degrees, and the bank continues as time goes on unless corrected.) Interestingly the Axis Viewer in F-14 does show a very minute amount of tilt to the right (the four areas of the trim diamond divided by the axis are not the exact same size.) This is harder to detect in Axis Viewer for different planes due to the size and shape of trim symbol.

Thanks!

[LeCuvier]

I have created Trim Preset commands for some fighters for a different reason: these tend to be trimmed badly nose-down when you start a mission airborn like in Instant Action, and by the time you have corrected the trim you're already under fire.
My solution works only if the trim in question has an axis command. In these cases the solution is very simple: I create a pushbutton command that sets the respective trim axis to the desired value. Afterwards I change the trim using the POV hat on my stick. Obviously that solution will not work if you have bound your trim axis to an analog input device.
For the Mosquito my Trim Preset command sets all 3 trim axes to desired values. This is done by adding this line to the file "default.lua" in the folder "...\DCS World OpenBeta\Mods\aircraft\MosquitoFBMkVI\Input\MosquitoFBMkVI\joystick":

{cockpit_device_id = devices.CONTROLS, pressed = device_commands.Button_17, down = device_commands.Button_54, up = device_commands.Button_52, value_pressed = 0.38, value_down = 0.18, value_up = -0.1, name = _("Trim Preset Airborne"),  category = _("Flight Control")},

If I wanted only to preset rudder and aileron, I would instead add this line:

{cockpit_device_id = devices.CONTROLS, down = device_commands.Button_54, up = device_commands.Button_52, value_down = 0.18, value_up = -0.1, name = _("Trim Preset Rudder and Ailerons"),  category = _("Flight Control")},

Unfortunately, not all planes have trim axes at all (the F-14 does), and some have just an axis for rudder trim. And the line of code of course is different for every aircraft. Not an optimal solution for you, but I wanted to mention it.

[Shahriar0]

Thanks for commenting.

I did run into this suggestion when I was researching this topic and, as you said, it's not the optimal solution for various planes.

Meanwhile, my problem has taken a bizarre turn which might steer it in a completely different direction! For the sake of thoroughness and ruling out that this is indeed a problem with the HOTAS and not the flight simulator, I did a whole of testing in two different programs, MSFS 2020 and X-Plane using mostly planes with jet engines (to eliminate the problem of propellers and torque and drift to left/right.) To my absolute surprise, I do NOT see any drift in any of the mentioned programs in several different planes that I tested, to the point that, I would like to say this issue of drifting is now limited to DCS and recent product releases of X52!

This is a headscratcher to say the least. I know from the perspective of Windows, my new X52 was treated as a new hardware device and I had to install my profiles both for X-52 and inside DCS. So there is a chance, there is something that triggers this problem, but I do not know what. I plug in my old X52, and all is good. I fly handsfree and there is no drift. I plug in my new X52 and the drift is immediate and very pronounced. Go to another simulator and there is no issue!

I very much like ED developers to chime in to shed some light on this and perhaps offer a solution. Still, my question is valid, how can we preset trims in DCS. This is something I used to do in X-plane myself (there is a line in aircraft.cfg for each plane that allows exactly that.) So we are not really asking ED to divulge something out of bounds for users.

[Shahriar0]

Bump.

[Shahriar0]

This question is still standing. ED, please provide a comment. I am sure someone over there readily knows the answer on how to enable presets for trims either per-module or for the entire program.

[Shahriar0]

I would like to provide an update to the original problem I ran into, which was airplanes drifting to right in DCS. It has been solved!

While continuing to research issues with X52, I ran into a post where someone was experiencing a particular problem with his rudder action. Rudder was either in full deflection to the left or full deflection to the right! Any slight twist in stick would send airplane rudder all the way to its full motion. Solution was to delete X52 calibration entries from Windows registry! Even though my problem seemed different, and the fact that I experienced no drifting to right (in the form of slight bank action) in MSFS 2020, I decided to give it a try. To my amazement, it worked! Now, the plane flies straight, as it should.

Just in case, others may experience weird issues with their X52 Hotas and read this thread in the future, I would like to offer the following solution:

- Back up your Windows Registry.

- Go to HKEY_CURRENT_USER -> System -> CurrentControlSet -> Control -> Media Properties -> Private Properties -> Direct Input

- Delete any entries inside the Direct Input folder that begins VID_06A3.

- Reboot your computer.

 

Even though my problem has been solved, I think knowing how to set trim presets in DCS would be beneficial to some. So I hope ED would still consider providing an answer to it.

Thanks.

Edited January 17, 2022 by Shahriar0