Dumb q - how do i set autopilot such that the plane flies at a fixed altitude?

[goot66]

No matter what i do, if i click A/P and then in try click BALT or RALT, nothing happens

How do i use A/P such that i can set my plane to fly at exactly for example 20,000 ft? 

[rob10]

It will be easier to give you answers if you post a track of what you're doing.

Try adding a small deadzone in your pitch controls.  Did you do a proper INS alignment if you cold started? Are you seeing any advisories or warnings in your left DDI?

It should mostly fly at desired altitude and press A/P followed by BALT.  In the F-18 you can't "dail up" a specific altitude, you have to fly to your desired altitude and turn it on.

[goot66]

Yes when i click on A/P and then i click either 'BALT' or 'RALT' i get the warning indicator flash 

why is that ? 

do they only work below a certain altitude  ?

[rob10]

RALT is limited to below 5K IIRC, BALT is not limited but may not work well at extreme heights (ie 40K).

Please see my original post for possible causes and please attach a track if you want better answers or more likely a direct solution

[PawlaczGMD]

I also have this issue. The stick has to be absolutely centered for BALT to kick in. I don't have a deadzone because I don't like it, so I have to wiggle it a bit.

However, I also have trouble engaging heading hold. It seems to activate but do nothing...

Edited April 22, 2024 by PawlaczGMD

[Tom Kazansky]

1 hour ago, PawlaczGMD said:

I don't have a deadzone because I don't like it,

+1

Deadzones kill precision in formation flying and air to air refuling. It makes no sense to spend hundreds of bucks for a good stick/base and add deadzones.

No offence to the work around here, but the limits in the DCS Hornet seem too narrow to be realistic.

[PawlaczGMD]

8 minutes ago, Tom Kazansky said:

+1

Deadzones kill precision in formation flying and air to air refuling. It makes no sense to spend hundreds of bucks for a good stick/base and add deadzones.

No offence to the work around here, but the limits in the DCS Hornet seem too narrow to be realistic.

Yes, the allowable stick deflection limit to engage AP should be non-zero.

I have damping clutches installed on my orion 2, so it doesn't always center perfectly.

[LeCuvier]

3 hours ago, PawlaczGMD said:

...I also have trouble engaging heading hold. It seems to activate but do nothing...

 

1. I have disabled the deadzone on my VRP stick, and I have no deadzone in the axis tuning for the FA-18C
2. I have no problem with AP/BALT. I adjust my flight path to level flight, which is easy on the Hornet, and engage AP/BALT. That does it.
3. However, I confirm the problem with AP/HDG. I had set the heading to 20 ° and engaged AP/HDG. The UFC shows HDG engaged, but the Hornet continues flying straight ahead.
    Only after I wiggled the stick a little bit, it turned to the 20 ° heading.

I attach a track demonstrating the issue.
@NineLine: Please report!

FA-18C AP HDG Bug.trk

[Tom Kazansky]

I just checked the BALT HOLD behaviour in the Hornet again, and what I find interesting is:

 

1) If your stick is not totaly centered in pitch (Y-axis) when you press BALT on the UFC, a warnig tone sounds, the BALT does not engage BUT(!) without doing anything else but moving the stick slightly into the center of the pitch (Y) axis, the BALT mode still engages. Again: This happens without another press of the BALT button on the UFC.

2) And this is why no. 1) is helpful: the BALT mode does not disengage by releasing the slightly uncentered stick, because (and that was news for me):

The limits in wich the stick must be centered to engage BALT are significantly smaller than those you have to exceed to disengage the BALT mode by deflecting the stick.

 

So as a workaround I recommend to move the stick in the pitch axis as soon as you hear the warning tone (that is heard after a non engaging BALT mode after BALT-button-press) until the BALT mode engages.

Btw. If your stick is uncentered in the x-axis, there is no problem at all with the BALT mode. You can even deflect the stick quite a bit to the side, as long as your pitch is centered to engage BALT.

 

EDIT:

and now something completely odd:

I slightly deflected the stick from the center in pitch axis, pressed BALT, the warning tone sounded and BALT did not engage (as expected), then I waited more than 10 sec before moving the stick to the center and BALT still engages (without pressing BALT on the UFC again). I have no proof from real life, but this seems odd, doesn't it?

Edited April 22, 2024 by Tom Kazansky

[SharpeXB]

Yes this behavior seems too odd to be realistic. Yet I’ve never seen this acknowledged by ED or any SME. A real aircraft that behaved this way would seem very dangerous to operate. 

[PawlaczGMD]

On 4/22/2024 at 3:59 AM, LeCuvier said:

1. I have disabled the deadzone on my VRP stick, and I have no deadzone in the axis tuning for the FA-18C
2. I have no problem with AP/BALT. I adjust my flight path to level flight, which is easy on the Hornet, and engage AP/BALT. That does it.
3. However, I confirm the problem with AP/HDG. I had set the heading to 20 ° and engaged AP/HDG. The UFC shows HDG engaged, but the Hornet continues flying straight ahead.
    Only after I wiggled the stick a little bit, it turned to the 20 ° heading.

I attach a track demonstrating the issue.
@NineLine: Please report!

FA-18C AP HDG Bug.trk 1.34 MB · 1 download

I see a similar thing. Moreover, attitude hold also behaves weirdly. It activates and damps all inputs, but the aircraft still floats left/right. I suspect that it accepts extremely small inputs from a non-centered stick, and just decreases them instead of eliminating them. It would be very dangerous if the real thing behaved like that.

When an AP is activated, a software deadzone on the relevant axis should be active, and only an obviously intentional deflection should be accepted as input.

And the acceptable deflection to engage AP should be comparable to the deflection that disengages it, not exactly zero.

 

EDIT: discovered it's the same thing with AP/HDG. You need to perfectly center the stick right after pressing it, or it will not engage.

Edited April 23, 2024 by PawlaczGMD

[PawlaczGMD]

I also have had absolutely no luck using ACL. The CPL AP does not engage. I'm not sure If I'm doing something wrong, or is it also the joystick deadzone issue.

Did anyone with these problems manage to use ACL without issues?

[Tom Kazansky]

On 4/26/2024 at 3:38 AM, PawlaczGMD said:

I'm not sure If I'm doing something wrong, or is it also the joystick deadzone issue.

You can test that easily by setting a large deadzone temporarily to both axis of your stick (and maybe rudders too), and see if that changes anything.

Edited April 27, 2024 by Tom Kazansky

[PawlaczGMD]

Yes, indeed the deadzone makes it impossible to engage CPL autopilot for ACL.

@NineLine could someone take a look at this? Summary:

-BALT AP needs the stick absolutely centered in the pitch axis to engage

-HDG AP needs the same in roll

-CPL AP needs both axes centered, at least for ACL, which makes it impossible to use if you don't use software deadzones.

This seems wrong and unrealistic for the AP to refuse to engage with such a minor input. And practically, some people don't want to use deadzones on their joysticks, and it really messes with AP use.

[goot66]

On 4/26/2024 at 9:29 PM, PawlaczGMD said:

Yes, indeed the deadzone makes it impossible to engage CPL autopilot for ACL.

@NineLine could someone take a look at this? Summary:

-BALT AP needs the stick absolutely centered in the pitch axis to engage

-HDG AP needs the same in roll

-CPL AP needs both axes centered, at least for ACL, which makes it impossible to use if you don't use software deadzones.

This seems wrong and unrealistic for the AP to refuse to engage with such a minor input. And practically, some people don't want to use deadzones on their joysticks, and it really messes with AP use.

totally agree

it defeats the purpose of autopilot!

 

[PawlaczGMD]

Playing more, AP behavior is very weird in more ways.

It seems to ignore roll trim inputs when AP is engaged, so if you're not roll trimmed when you switch it on, it will roll. Attitude hold does not help with this... You would think that it would be its main function.

The plane is just all over the place in AP without deadzones, it's very frustrating to be forced to use them. It kills my formation/AAR precision.

[rob10]

11 minutes ago, PawlaczGMD said:

Playing more, AP behavior is very weird in more ways.

It seems to ignore roll trim inputs when AP is engaged, so if you're not roll trimmed when you switch it on, it will roll. Attitude hold does not help with this... You would think that it would be its main function.

The plane is just all over the place in AP without deadzones, it's very frustrating to be forced to use them. It kills my formation/AAR precision.

Which AP mode?  BALT/RALT ONLY control altitude, you can roll as desired without affecting it (as long as you don't give pitch input) and that's as designed.  Attitude hold should hold whatever pitch and roll you are at when it's engaged.  Are you saying it continues to roll further if you're not trimmed with ATT hold?

I get that you have problems with getting AP to engage, but I'm going to guess that the reason there aren't a lot more complaints is that most people don't have an issue.  I have a Virpil WarBRD base with no deadzone and I basically never have issues getting it engaged, so it's not blanket "impossible" without a deadzone.  Note that I'm not opposed to a tweak to not require quite as tight tolerance, just explaining why it might not be an ED priority.

Edited April 29, 2024 by rob10

[PawlaczGMD]

7 minutes ago, rob10 said:

Which AP mode?  BALT/RALT ONLY control altitude, you can roll as desired without affecting it (as long as you don't give pitch input) and that's as designed.  Attitude hold should hold whatever pitch and roll you are at when it's engaged.  Are you saying it continues to roll further if you're not trimmed with ATT hold?

I get that you have problems with getting AP to engage, but I'm going to guess that the reason there aren't a lot more complaints is that most people don't have an issue.  I have a Virpil WarBRD base with no deadzone and I basically never have issues getting it engaged, so it's not blanket "impossible" without a deadzone.  Note that I'm not opposed to a tweak to not require quite as tight tolerance, just explaining why it might not be an ED priority.

 

Yes, the plane can still drift in roll in BALT and ATT hold engaged. It also refuses my roll trim input, so I can't trim it out in roll while AP is engaged. And here I mean if I have asymmetric loadout, so roll trim needs to vary with speed.  If I don't trim it out perfectly at given speed before engaging AP, I still have to input roll on the stick to keep attitude. ATT works more like input damping than hold.

It only works as I expect it to in BALT and HDG hold mode together. 

 

[Tom Kazansky]

3 hours ago, rob10 said:

I have a Virpil WarBRD base with no deadzone and I basically never have issues getting it engaged, so it's not blanket "impossible" without a deadzone. 

Same here, but please tell me, with the hand on stick and you press BALT (just once), do you never hear the autopilot warning tone before it finally engages (like I described above, due to a small deflection and a return to center afterwards)?

And this "afterwards" can mean seconds, if you are deflecting the stick just 0.5%.

This should be looked at with priority, imho.

[PawlaczGMD]

1 hour ago, Tom Kazansky said:

Same here, but please tell me, with the hand on stick and you press BALT (just once), do you never hear the autopilot warning tone before it finally engages (like I described above, due to a small deflection and a return to center afterwards)?

And this "afterwards" can mean seconds, if you are deflecting the stick just 0.5%.

This should be looked at with priority, imho.

Yes from me, I often hear the AP warning and beep just in that way!

 

Also can you guys check this: Engage just BALT, and trim ailerons left or right. For me with AP on, it treats the trim input kind of like roll input - it will bank, but then stop banking when I let go of the trim hat. It doesn't permanently trim in AP. Trim works just  fine for me outside of AP. Very weird behavior.

Edited April 29, 2024 by PawlaczGMD

[PawlaczGMD]

5 hours ago, rob10 said:

Which AP mode?  BALT/RALT ONLY control altitude, you can roll as desired without affecting it (as long as you don't give pitch input) and that's as designed.  Attitude hold should hold whatever pitch and roll you are at when it's engaged.  Are you saying it continues to roll further if you're not trimmed with ATT hold?

I get that you have problems with getting AP to engage, but I'm going to guess that the reason there aren't a lot more complaints is that most people don't have an issue.  I have a Virpil WarBRD base with no deadzone and I basically never have issues getting it engaged, so it's not blanket "impossible" without a deadzone.  Note that I'm not opposed to a tweak to not require quite as tight tolerance, just explaining why it might not be an ED priority.

 

Are you sure you don't have a deadzone? I never had it in game, but my WW stick has its own software deadzone, that you can edit in WW software. The default was non-zero, I edited it to zero. Might be a similar story for Virpil.

[Tom Kazansky]

1 hour ago, PawlaczGMD said:

Are you sure you don't have a deadzone? I never had it in game, but my WW stick has its own software deadzone, that you can edit in WW software. The default was non-zero, I edited it to zero. Might be a similar story for Virpil.

that's a valid point!

my Virpil WarBRD-D base in the default configuration has a small software deadzone. The Virpil rudders as well. You can see in the VPC Configuration tool, that the raw values still change but the output value stays at 50% while slowly moving over that deadzone.

so the DCS Hornet AP issue would also be there for us Virpil users if we turned that off, I assume. It seems to be just a matter of programmed limits in DCS, so why not make those just a little bit larger to suit more users' hardware without forcing them to make a deadzone that kills an important part of the experience?

I also assume, that the real Hornet does not have a deadzone, but its AP BALT mode does engage when the other limits are met (and most probably without a warnig tone). Can we all agree in this point?

Edited April 29, 2024 by Tom Kazansky

[PawlaczGMD]

8 hours ago, Tom Kazansky said:

that's a valid point!

my Virpil WarBRD-D base in the default configuration has a small software deadzone. The Virpil rudders as well. You can see in the VPC Configuration tool, that the raw values still change but the output value stays at 50% while slowly moving over that deadzone.

so the DCS Hornet AP issue would also be there for us Virpil users if we turned that off, I assume. It seems to be just a matter of programmed limits in DCS, so why not make those just a little bit larger to suit more users' hardware without forcing them to make a deadzone that kills an important part of the experience?

I also assume, that the real Hornet does not have a deadzone, but its AP BALT mode does engage when the other limits are met (and most probably without a warnig tone). Can we all agree in this point?

 

I wonder if this is unique to the Hornet. I don't have the F-16 or 15, but if someone here does, it would be useful to see if their AP behaves the same. 

I agree with your point on how it should work. I cannot imagine the real plane will refuse to engage ACL because your hand is on the stick.

[Razor18]

You can check whether your joystick is offset from dead center, if you go into Controls, choose Axis command, and look at the pitch axis in the joystick column. If you move the joystick fwd and back you can see the white lines moving accordingly. In center position there should be no white line be visible, meaning dead center. If you let go of your joystick, but you can still see a tiny little part of the white line being visible left or right, then your joystick is not centered for the game, even if you think your joystick is phisically in the middle, because you do not touch it.

And it is easier to set a Deadzone of 1 or 2 in the Curve setting window of DCS, this will make the tiny little white line go away. Try to find the minimum deadzone though, for obvious reasons.

[PawlaczGMD]

26 minutes ago, Razor18 said:

You can check whether your joystick is offset from dead center, if you go into Controls, choose Axis command, and look at the pitch axis in the joystick column. If you move the joystick fwd and back you can see the white lines moving accordingly. In center position there should be no white line be visible, meaning dead center. If you let go of your joystick, but you can still see a tiny little part of the white line being visible left or right, then your joystick is not centered for the game, even if you think your joystick is phisically in the middle, because you do not touch it.

And it is easier to set a Deadzone of 1 or 2 in the Curve setting window of DCS, this will make the tiny little white line go away. Try to find the minimum deadzone though, for obvious reasons.

Yeah, I know it is not centered by a fraction of a percent. I know how to fix it, I don't want a deadzone though, as it makes flying less precise. I think it is incorrect that such a small input prevents AP from engaging. I want ED to reconsider this behavior.