F-15C trim issues.

[Thinder]

Hey! Merry X-Mass to start with.

 

I wonder if it's my settings (working 100% with the Mirage 2000C) or something else, but as far as I've tried, I never was able to get stable trimming from the F-15C.

 

The Aircraft doesn't stay level flight in both roll and pitch despite my best efforts to trim it, both axis trim set on my stick and going through the "reset" trim drill several time over.

 

Anyone has experienced this or knows a solution to it?

 

Thanks in advance and enjoy your gaming.

 

 

[HiJack]

Been like this all the time and not going to be fixed I believe. According to real pilot interviews it should not need to be manually trimmed either. Just set it level with the stick and it should stay there even in speed increases.  

[Thinder]

2 hours ago, HiJack said:

Been like this all the time and not going to be fixed I believe. According to real pilot interviews it should not need to be manually trimmed either. Just set it level with the stick and it should stay there even in speed increases.  

 

Thanks mate!

[Lurker]

2 hours ago, HiJack said:

Been like this all the time and not going to be fixed I believe. According to real pilot interviews it should not need to be manually trimmed either. Just set it level with the stick and it should stay there even in speed increases.  

 

Real pilots of which aircraft? The F15C we have in the game does not feature a Digital Flight Control System that you would find on the Hornet, or the F16C or more modern variants of the F15 etc. It is definitely NOT a fly by wire system. The aircraft can certainly be trimmed out, but do not expect it to be completely hands-off. 

Edited December 24, 2020 by Lurker

[HiJack]

8 hours ago, Lurker said:

 

Real pilots of which aircraft? The F15C we have in the game does not feature a Digital Flight Control System that you would find on the Hornet, or the F16C or more modern variants of the F15 etc. It is definitely NOT a fly by wire system. The aircraft can certainly be trimmed out, but do not expect it to be completely hands-off. 

 

It was a blog about the F-15C I believe and they were discussing use of the autopilot. The interviewed pilot said he never used the autopilot because he could just set the stick and that heading and aspect was kept even when increasing speed. I don't know if the pilot was just exaggerating this but sounded like he never used the autopilot functions. Don't know if he was referring a clean setup either. I'm not complaining as my autopilot is working on level flight and even set at an angle sometimes, so I'm happy. 

[Ozmandi]

I just figured this out today.
 

A few weeks ago I created a mission with a long flight time(50-60mins).  Nothing else going on, just a flight from one airfield to another.
The first few times I flew the mission - the plane would get harder to keep level, the further I flew, and I was using TRIM to maintain my heading the whole way.  It was so bad that if auto pilot was disengaged I never could engage it again, because I couldn't get the plane back to a level path.

 

Yesterday I flew it again and kept an eye on the TRIM circle on the Controls Indicator Display. During the flight, as I TRIMMED, the little circle would stay near the center and sometimes not even look like it moved.  The further I flew the TRIM no longer would keep the plane on path so I would need to use the stick to make heading corrections and at that point the autopilot would disengage.  Once the auto pilot disengaged - the TRIM circle on the Controls Indicator Display immediately moved to the LEFT 3/4 of the way from the center.   I could never get it back to center so it was a yo-yo-roller-coaster ride down to the Final Approach because the controls were so messed up.

So, today I flew it again but this time I didn't use TRIM.  I leveled the plane out at just over 40k feet and engaged A\H autopilot and the plane flew straight and level for 280 miles!  

I wasn't used to any of the planes ever flying that level so I thought something was wrong.  LOL

 

I plan on flying it again to verify it but from reading the previous post I think I know not to use TRIM in the F-15 now.  

REALLY would have loved to read that in one of the manuals!

 

 

[HiJack]

4 hours ago, Ozmandi said:

I just figured this out today.
 

A few weeks ago I created a mission with a long flight time(50-60mins).  Nothing else going on, just a flight from one airfield to another.
The first few times I flew the mission - the plane would get harder to keep level, the further I flew, and I was using TRIM to maintain my heading the whole way.  It was so bad that if auto pilot was disengaged I never could engage it again, because I couldn't get the plane back to a level path.

 

Yesterday I flew it again and kept an eye on the TRIM circle on the Controls Indicator Display. During the flight, as I TRIMMED, the little circle would stay near the center and sometimes not even look like it moved.  The further I flew the TRIM no longer would keep the plane on path so I would need to use the stick to make heading corrections and at that point the autopilot would disengage.  Once the auto pilot disengaged - the TRIM circle on the Controls Indicator Display immediately moved to the LEFT 3/4 of the way from the center.   I could never get it back to center so it was a yo-yo-roller-coaster ride down to the Final Approach because the controls were so messed up.

So, today I flew it again but this time I didn't use TRIM.  I leveled the plane out at just over 40k feet and engaged A\H autopilot and the plane flew straight and level for 280 miles!  

I wasn't used to any of the planes ever flying that level so I thought something was wrong.  LOL

 

I plan on flying it again to verify it but from reading the previous post I think I know not to use TRIM in the F-15 now.  

REALLY would have loved to read that in one of the manuals!

 

 

The F-15C is very sensitive to stick movements so make sure you set a decent amount of deadzones on the pitch and roll axes in DCS. I have mine set to 3 on both and that seams good for mine but it may differ for each hotas. The autopilot will not stay fixed if there are a tiny bit of movement in the stick. 

[henshao]

man I have set my deadzones to 95 and the autopilot will still drift considerably over time, ED swears there is nothing wrong with it but I am certain the game is looking at the input BEFORE deadzone when it comes to certain functions

[HiJack]

57 minutes ago, henshao said:

man I have set my deadzones to 95 and the autopilot will still drift considerably over time, ED swears there is nothing wrong with it but I am certain the game is looking at the input BEFORE deadzone when it comes to certain functions

Try to set a deadzone on the axes on the device controlpanel in Windows. You still need a deadzone in DCS on about 3. 

Edited December 28, 2020 by HiJack

[henshao]

2 hours ago, HiJack said:

Try to set a deadzone on the axes on the device controlpanel in Windows. You still need a deadzone in DCS on about 3. 

 

must be a windows 10 feature I don't see that option

[HiJack]

6 hours ago, henshao said:

must be a windows 10 feature I don't see that option

No, all Windows versions have one. Just search for "Game Controller" on your start button and start the "Set up USB game controllers". When started you should see a list of the controllers you have connected. Select the one and explore the Properties and you will find the deadzones there. 

[draconus]

4 hours ago, HiJack said:

No, all Windows versions have one. Just search for "Game Controller" on your start button and start the "Set up USB game controllers". When started you should see a list of the controllers you have connected. Select the one and explore the Properties and you will find the deadzones there. 

You must have had some additional software installed. There's no deadzone settings in default Windows 7-10 joy.cpl.

[OpticFlow]

On 12/24/2020 at 2:03 PM, HiJack said:

Been like this all the time and not going to be fixed I believe. According to real pilot interviews it should not need to be manually trimmed either. Just set it level with the stick and it should stay there even in speed increases.  

 

It works exactly like this in the game. After take off, level out, engage AP Attitude Hold and proceed to do your flying. The plane goes where you put the velocity vector (on the HUD) and you don't need to touch anything besides the stick X/Y axes. Don't touch the trim buttons at all. You could also use this mode for air refueling, it's smoother with it on.

[henshao]

2 hours ago, OpticFlow said:

 

It works exactly like this in the game. After take off, level out, engage AP Attitude Hold and proceed to do your flying. The plane goes where you put the velocity vector (on the HUD) and you don't need to touch anything besides the stick X/Y axes. Don't touch the trim buttons at all. You could also use this mode for air refueling, it's smoother with it on.

it should work this way

 

WITHOUT the AP engaged

 

such is the very purpose of the Control Aug System  and Pitch Trim Comp

[737Driver]

I have tried and tried to make the autopilot work.  Would you confirm the key-presses or settings for me. Thanks.

 

As an addendum, it's a great shame that some work couldn't be done on the F-15's controlability particularly on the ground.  Its instability is bordering on the farcical.

[Ozmandi]

1 hour ago, 737Driver said:

I have tried and tried to make the autopilot work.  Would you confirm the key-presses or settings for me. Thanks.

 

As an addendum, it's a great shame that some work couldn't be done on the F-15's controlability particularly on the ground.  Its instability is bordering on the farcical.

 

@737Driver Here's a list of things that helped me figure out why my plane had problems with autopilot.

I'll list them here just in case one might be of help.

 

Have you changed any of your controls? 

If not then Attitude HOLD should be A and Altitude HOLD should be H on your keyboard.

Autopilot min/max

Plane must be within these limits.

*Attitude HOLD

PITCH +/- 45 degrees

ROLL +/- 60 degrees

G between 0g and 4g

 

*Altitude HOLD

Attitude HOLD engaged first.

CLIMB\DESCEND rate below 2000\ft min

*credit = @N22YF F-15C Training Missions! - Page 2 - F-15C for DCS World - ED Forums (eagle.ru) Mission 4. Navigation, autopilot, and fuel management

 

 

First thing you should do is make sure your keyboard bindings are set up correctly and that they are not conflicting with something else.

Open the CONTROLS menu and select the F15.

Then hit H on your keyboard and see if the Autopilot - Altitude Hold action is highlighted and then check A the same way.  You'll see a RED marker if it's in conflict with another control.

While you are in here check your Pitch, Yaw and Rudder settings. (I had problems with my Rudder settings that prevented me from using Autopilot, so my advice is to double check this).

 

If everything is set up and working as it should, then jump into a Free Flight Instant Action mission.
First thing to check when the mission starts is where your throttle is set - make sure it's not in the OFF position.  

 

Get the plane up around 350-400\knots and manualy get it to fly level.

Then hit A on your keyboard.

Check to see if the Attitude HOLD light is on in the panel on the lower right.  If it is on then hit H and see if the Altitude HOLD light comes on.

IF both of those are on, then your autopilot is working.

Small stick adjustments can be made without disengaging the autopilot but large stick movements will disengage the autopilot.

 

Double check all of this and try a Free Flight mission and let me know if the Autopilot lights ever come on.

 

Good Luck!

Oz

Edited January 5, 2021 by Ozmandi

[draconus]

6 hours ago, 737Driver said:

As an addendum, it's a great shame that some work couldn't be done on the F-15's controlability particularly on the ground.  Its instability is bordering on the farcical.

Please explain what are you trying to achieve and maybe we can help you. For a ground control 3 things are basically all there is to it.

1. Use Nose Gear Maneuvering Range ("S" key, must be held, selects maneuvering range 45 degrees) to cut tight corners.

2. If you fall over you're too fast and turn too tight.

3. To stay in a straight line use rudders precisely (axis curves can help here).

Edited January 5, 2021 by draconus