Trimming issues?

[DrDetroit]

Hi guys, gals,

I noticed that the Viper seems to need a lot of trimming while flying straight and level, at least for me.  Even then, the nose will slowly go up or down, or roll slowly left right, regardless of trim settings.  Anybody else have this issue? Might be my curves are set with sensitivity too high or something.

I decided to check with you fine folks about this issue, as I just watched a vid where a F-16 pilot explains that he almost never used the trim hat, except maybe a little yaw during takeoff/landing, but never vertical trim.

Anyhow, just wondering about this issue.

Thanks and good day!

DrDetroit

 

Edited August 7 by DrDetroit

[Scotch75]

That shouldn't be the case. The F-16 self trims to 1G in pitch. So you set your attitude, hold, the FCS should trim. Lateral trim is required with asymmetric loads (also having the TGP installed will have an effect).
You should check with other axis/button conflictions using the RCTRL ENTER pop-up.
Cheers!


Sent from my SM-G998B using Tapatalk

[DrDetroit]

Yea, after checking my loadout, I had forgotten that the targeting pod was installed, that seemed to throw things out of wack.  It wasn't really bad, but enough that it was a pain in the butt when not in AP.

Thanks for the help @Scotch75!

Edited August 7 by DrDetroit

[RyanR]

Other thought: the autopilot stays on with moderate stick input. Lots of new Viper people (myself included) instinctively start trimming when they're actually fighting the AP.

Other than that, the F-16 just needs roll compensation for asymmetric load.

-Ryan

[RogueSpecterGaming]

5 hours ago, DrDetroit said:

Hi guys, gals,

I noticed that the Viper seems to need a lot of trimming while flying straight and level, at least for me.  Even then, the nose will slowly go up or down, or roll slowly left right, regardless of trim settings.  Anybody else have this issue? Might be my curves are set with sensitivity too high or something.

I decided to check with you fine folks about this issue, as I just watched a vid where a F-16 pilot explains that he almost never used the trim hat, except maybe a little yaw during takeoff/landing, but never vertical trim.

Anyhow, just wondering about this issue.

Thanks and good day!

DrDetroit

 

As you increase speed or decrease speed the nose will act according going up or down. 

 

For roll trim, pretty much what others have said. 

[Pavlin_33]

On 8/8/2025 at 4:40 AM, RogueSpecterGaming said:

As you increase speed or decrease speed the nose will act according going up or down. 

Why is that?

[rob10]

7 hours ago, Pavlin_33 said:

Why is that?

More (or less) lift generated with change in speed.

[Czar]

Keep in mind you guys, with any TGP installed, the Viper needs a bit of rudder trim out of neutral if you're after a perfectly steady trimmed plane. Not mandatory.

I found myself going after trimming roll all the time up high and a bit of rudder trim resolved the unwanted yaw/roll. (it is really tiny)

[Pavlin_33]

1 hour ago, rob10 said:

More (or less) lift generated with change in speed.

So increase/decrease in lift causes a pitching moment to develop?

[RogueSpecterGaming]

4 hours ago, Pavlin_33 said:

So increase/decrease in lift causes a pitching moment to develop?

Yes. That is how aerodynamics works. That is the core basics of how generating lift works. Increase speed to increase lift, and decrease speed to decrease lift. That is why losing engine power makes the plane/jet slow which then makes it fall out of the sky. 

[Pavlin_33]

7 hours ago, RogueSpecterGaming said:

...Increase speed to increase lift, and decrease speed to decrease lift...

One small remark here: this is true for a fixed angle-of-attack. In general lift is a combination of airspeed and AoA, meaning you can have same value of lift in both high and slow speed regimes of flight (and anything in between).

[RogueSpecterGaming]

9 hours ago, Pavlin_33 said:

One small remark here: this is true for a fixed angle-of-attack. In general lift is a combination of airspeed and AoA, meaning you can have same value of lift in both high and slow speed regimes of flight (and anything in between).

Yeah I was just saying the basics as it didnt seem he understood the bare minimum for level flight scenario.

[Sarge55]

Still, unless he’s rocking the throttle back and forth the plane shouldn’t be porpoising. FLCS should be managing the pitch. 

[Pribs86]

I never trim in the Viper, ever. If I trim for roll, like I used to, when I drop some bombs I'd trim a little, then drop more bombs then trim back. After I'd land to rearm and refuel I could never get the trim centered again. It's forever in a constant state of roll from then on... even if I look at the trim needles on the left console to try to get them centered. I can never quite get it dead on the nuts again.

Edited 22 hours ago by Pribs86

[WHOGX5]

11 hours ago, Pribs86 said:

I never trim in the Viper, ever. If I trim for roll, like I used to, when I drop some bombs I'd trim a little, then drop more bombs then trim back. After I'd land to rearm and refuel I could never get the trim centered again. It's forever in a constant state of roll from then on... even if I look at the trim needles on the left console to try to get them centered. I can never quite get it dead on the nuts again.

Yeah, there were complaints when the DCS F-16C released like 5 years ago that the trim hat was too sensitive, but ED always said it was correct-as-is (which it obviously isn't). I have unironically unbound my pitch trim from my HOTAS in the DCS F-16C, because just accidentally bumping it will mean that you'll never be able to trim it again. It's really crazy when you fly other ED modules where the trim isn't sensitive at all, and you can get a 100% perfect trim with no effort at all, by simply trimming in the direction you want to trim. With the DCS F-16C you have to do 0.01 second microbumps of the trim hat, and once you do that 10-20 times in alternating directions, you might get a decent (but not good) trim by pure chance. Would be nice if they made it less sensitive, or gave us a special option to set the sensitivity of the trim like they let us set the sensitivity of the stick gains and stuff, but I'm not holding my breath.

[DrDetroit]

13 hours ago, Pribs86 said:

I never trim in the Viper, ever. If I trim for roll, like I used to, when I drop some bombs I'd trim a little, then drop more bombs then trim back. After I'd land to rearm and refuel I could never get the trim centered again. It's forever in a constant state of roll from then on... even if I look at the trim needles on the left console to try to get them centered. I can never quite get it dead on the nuts again.

Yes, this!  I can't get it to center if I trim a bit for having a targeting pod.

 

[Pribs86]

3 hours ago, WHOGX5 said:

Yeah, there were complaints when the DCS F-16C released like 5 years ago that the trim hat was too sensitive, but ED always said it was correct-as-is (which it obviously isn't). I have unironically unbound my pitch trim from my HOTAS in the DCS F-16C, because just accidentally bumping it will mean that you'll never be able to trim it again. It's really crazy when you fly other ED modules where the trim isn't sensitive at all, and you can get a 100% perfect trim with no effort at all, by simply trimming in the direction you want to trim. With the DCS F-16C you have to do 0.01 second microbumps of the trim hat, and once you do that 10-20 times in alternating directions, you might get a decent (but not good) trim by pure chance. Would be nice if they made it less sensitive, or gave us a special option to set the sensitivity of the trim like they let us set the sensitivity of the stick gains and stuff, but I'm not holding my breath.

I know it isn't realistic, but even a trim reset to return everything to zero would be nice. The warbirds have it even though it isn't realistic. Sure helps re-center to zero again.

[WHOGX5]

1 hour ago, Pribs86 said:

I know it isn't realistic, but even a trim reset to return everything to zero would be nice. The warbirds have it even though it isn't realistic. Sure helps re-center to zero again.

Honestly, I don't even care about realism at this point. Just any conceivable solution that lets me trim my aircraft properly would suffice at this point.