Unable to keep f16 flying straight, drifts in both directions.

[mazin]

I am having a difficult time keeping the F16 straight and aligned with the runway. It seems to drift in both direction after some time by +1/-1 degrees in heading. My load is balanced, so the FBW should be able to keep it where I have pointed the FPM. I used L-CTRL Y to show the bank angle, and the bank angle changes by +/-1 after some time, even if I do not touch the flight stick. The drift gets worst at slower speed, when one is about to land. Lot's of you tube videos for landing tutorial show once the FPM is aligned with the runway, the f16 does not drift. For me to keep it straight I need to keep adjusting the roll by +1/-1 continuously. I tried using trim, but it seems to over-trim and the drift becomes worst. 

I am using  VKB gladiator NXT EVO - made sure it is calibrated and I have a deadzone of 5. Made sure no other keys are binded to the roll axis.

I copied the DCS F16  landing tutorial to make a custom mission with a balance load, so I can learn to do  a simple straight  landing.

Any help will be appreciated.

Attached are some tracks.

slight drift 3.trk slight drift 2.trk

[Aquorys]

Sounds normal and realistic to me. The flight control system does not auto-trim for roll, and trim is virtually never perfect. I'd rather say that roll trim being perfect with a balanced loadout, until you touch it, is a DCSism, as you called it.

[skywalker22]

As said, that a normal behavior. I am sure you have trimmers bind to buttons (so digital inputs), in F-16 trimmers are analog potentiometers where you can trim way more precisely.

Hint: use auto pilot for "fixing" roll thing, for Pitch (keep same pitch) or Attitude (fly horizontally), while keeping the left switch in the middle Attitude Hold.

[Dawgboy]

Also, ensure no other input devices are mapped to the various control surface keybinds beyond what you expect to be mapped.  

[SickSidewinder9]

You're saying that when you're near stall the plane doesn't fly dead straight?  I don't see what the problem is.  Especially if you have any wind or targeting pods mounted.  Don't adjust the roll trim.  An amateur mistake in the real world is trying to fly the plane with the trim.  Fly the plane.  Use the flight controls.
Have you ever been on a plane before IRL?  Most airliners now are fly-by-wire.  Watch the wingtips out the window when you are landing.  You are rocking back and forth left to right.  Every single time.  The lower you get, the more it does it.  There is a thing called ground effect:  The air being knocked down by the wings bounces off the ground and pushes back up on the wings, so after you cross the runway threshold and are very near the ground, the plane has a tendency to float a bit, and there's no reason for this to happen perfectly evenly and dead straight.  Even if the flight control system automatically compensated for this, there's no way it wouldn't wobble because of the air is swirling.  The air is swirling around parts of the plane, always.  The closer you get to a stall (and the higher alpha) the more it swirls.  You can hear the wind noise change in game, just like you probably would irl.

This is a sim, not an arcade game, so they have replicated stuff like that.  On top of that, landing the F-16 just right really does take some practice.  It might be a little bit easier in real life with real flight training, peripheral vision, and the sensation of movement.  Either way, what you say you're experiencing doesn't sound very strange, it sounds like flying a plane.

Edited June 22, 2023 by SickSidewinder9

[mazin]

Thanks for the reply. It is not only when near the stall speed or the runway threshold, but also around 200-250 knots. The drift is more prominent as you get close to the stall speed i.e. close to the runaway, I think this is what you are referring as ground effect. It seems the drift is effected by the landing gear. In my mission, when I am 15nm from the runway (at heading 324), if I do not lower the landing gear there is no drift, I can just leave the flight stick, and it stays at current heading, but when the gear is lowered the f16 starts to drift and needs +/- correction in roll constantly. I am not using any trim, just flying the plane.  I did not see people correcting the drift on Youtube tutorials for landing, so I thought maybe I am doing something wrong. Anyway thanks for the detailed reply, I will keep at it, until I get better.

 

[SickSidewinder9]

Again, normal.
Planes don't want to fly straight like how cars tend to self center.  That's just how they work.  Even your car will kinda drift with the slope of the road.

Edited June 28, 2023 by SickSidewinder9
grammar and spelling