F-15 Strike Eagle banking left

1st Official Post

    Hi guys, and thx for a great sim.

    I'm a bus driver as well as a fighter flyer, and like to buzz around with the F-15 and F-18. But my F-15 always drifts into a left bank which get worse and worse, and I get very much off-track if not using autopilot. I have checked my sticks, compared to the F-18 (going straight and steady), and compared to P3D where I fly many fighters and airliners, no offset there. On my TM Warthog system I have only one free slider for testing aileron correction. Doing this, upsetted my elevators. So my experience so far there is a drift in the F-15 model I cannot get rid of. There are others in my local forum that experience the same thing. Could you please look into this?

    • Official Post

    That could be the aileron trim. But the aileron trim in the F18 and F15 are pretty much identically, so its strange only the F15 drifts left for you. Check that your assigned aileron trim is correctly calibrated to zero. Maybe a deadzone for the axis will help as well, there are probably also options in the Warthog Joystick software.

    Regards,
    Jan

    Jan,
    I see the left roll drift in the F15 also - and not in the F18. I used the external DLL example to document the problem - looking at the angular velocity printouts along with the controls (nothing printed out for Aileron Trim though). It is slight but depends on throttle setting ( could there be just a little pfactor??). Here are the snapshots.

    Edited once, last by whitav8 (April 10, 2017 at 10:57 PM).

    • Official Post

    Hi Dave,

    Thanks! Ok I added a tiny bit of deadzone (0.1%) for analog aileron trim in the F18/F15 flight controller.
    I can't reproduce the issue on my end so I hope this little fix will help. This could be published together with the autopilot advanced that I'm working on, so I don't know when you will receive it at your end.

    Can you confirm that the issue is not present on your installation if you remove the analog aileron trim input?

    Regards,
    Jan

    @IPACS,
    I made a couple of keyboard keys the left and right aileron trim assignments but just a single push is too much and there is no push of a key for the other way that isn't too much the other way - i.e. no true zero Aileron Trim position. So I deleted those assignments and the F18 is fine again and the F15 seemingly has less desire to bank left but it still does to about the 3 degree position and stays there.
    The DLL code snippet that modifies the Rudder, Elev, or Aileron is commented out when I compiled it. The behavior is the same with or without the DLL.

    I'm not saying this is a big deal - just wanted to support the OP (I see it too) - funny that the F18 is fine.

    Dave

    Dave could you try keyboard assignments for rudder trim? It might give finer tuning or achieve a centred configuration. In real life most rudder movement is under automatic control as the F-15 has very high adverse yaw without rudder input. This complexity might allow some room for minor effects in the Aero model.

    Thx guys for checking this. To me, this is a big nuisance. As said before I have no trim assigned for ailerons. Trying buttons only gives huge banks that are hard to correct. I use only button trimming for elevators, which works in tiny steps as with FSX and P3D. But trying this for ailerons is another world as described...plane is banking in huge steps. I also tried sensivity and deadzones, to no avail.

    Overloaded,
    The sim should start with Aileron trim and Rudder Trim = 0 and as long as we don't touch them or asssign anything to them at all, they should remain "0". The issue is why is the F15 the ONLY jet aircraft (propeller aircraft have pfactor) that has the problem - what is different about it and why can't it be fixed. OR maybe that is actually part of the F15 sim and the others just don't have that detail??

    My F-15 is fine. Whatever the reason for some installations to have an out of trim condition it is not unnatural in real life. After major work an aeroplane's aerodynamic trim will be slightly out and control surface trimming gets adjusted. If rudder and aileron trim (not rudder and aileron movement) is assigned to keyboard presses it might help to zero out the drift. The trim order as I'm sure you know is elevator, rudder and then aileron. Not trimming rudder will not work. If keyboard presses or joystick buttons are too crude, a spare control axis might be temporarily assigned to do fine tuning. I like to change my piston engine blue lever/rpm axis to elevator trim when using the 737.

    Many people don't have the luxury of having an extra slider for aileron trim. Neither have I as I have to use my only one for speedbrake. When I did try this slider for aileron trim, it did not work well. As whitav8 says, it should remain "0". I have been simming since the Dragon 32 computer, and this is the first time I experience this drift. Reality is maybe as you describe, but I think this should not be simulated for jets. Us simmers are wing clipped contra reality.

    I got my update and Utah in and tried the F-15 again. Do you mean a very slight drift into a left bank that takes about 45 seconds to get to 5 degrees of bank? In real life that would be the most stable plane in history. It would be more authentic if it got faster with time and drifted left or right randomly.