Fly by wire aircrafts Constant pitch up slightly.

Hello guys.

I recently bought F-16C Viper and Mirage 2000C. High performance aircrafts on the best simulator game ever.

However during straight and level flight (Stable Speed) and with the joystick centered (even without joystick plugged in) the aircrafts tend to pitch up slightly over time. Especially in mirage it is most noticable.

For example at 380 knots straight and level the pitch up rate is going to make my vertical speed +500 fpm in about 30 seconds. With the f-16 the effect is less noticeable but it is happening also.

I tried removing the joystick the restart the game and tried with keyboard only and it is still happening.

Does this happen to anyone else or is it just me?

Is there an option to counteract this tendency to pitch up?

My DCS version is the latest Stable.

Thanks!!

Check if you have double bindings. And check if you have a deadzone setup for the axis.

Thanks for the reply.

No double bindings. Tried pitch deadzone at 50%and also tried without joystick connected.

The effect is not noticable easily. I need to set the aircraft straight and level for sometime to see a difference.

I just wanted some folks to check if this is happening so i can make a report ticket to be fixed.

To my mistake i should post this thread bugs section.

You could try to trim the aircraft

Yes this is an option but the flight control system of these 2 aircrafts is maintaining level flight in pitch (in reality) if no input is made and trimming with button control is not so precise. Once i trim down then the other issue arise, constant slight pitching down.

I choose to buy these 2 aircraft because of the fly by wire system and auto trim function and trimming up/down would disappoint me.

Are you level? They auto trim to 1G, so if you aren’t level(pitchers up or down) it will pull automatically to keep 1G, same thing with any bank, it will automatically pull 1G

I told an example. Flying straight and level 0 feet per minute on the vsi and 380 knots. I stop making inputs on the controls (even no joystick connected) and the aircraft starts pulling up slightly, at the same speed that in about 30.seconds my vsi would show at about 500 feet per minute climb.

Very slight pitch rate, not noticable to the "naked eye".

This example happens on the Mirage but lesser on the F-16 also less noticable again to the "naked eye"

That means that whenever i have to set various systems in cockpit and let handsfree on the controls i will have to correct pitch afterwards at the same speed which is not correct for an auto trim aircraft.

I really would like someone to test and correct me if I'm wrong and i could make a video so you can see.

Do you have the Nevada map? I can send you a track but I like doing this kind of stuff in Nevada (it's a Test and Training Range after all..) if not Caucasus is fine.

Likewise you can upload short tracks to this forum... they are much more helpful than videos.

I don't have nevada. I would like to see this issue sorted so i really would appreciate if someone check it out.

Yes this is an option but the flight control system of these 2 aircrafts is maintaining level flight in pitch (in reality) if no input is made and trimming with button control is not so precise. Once i trim down then the other issue arise, constant slight pitching down.

 

I choose to buy these 2 aircraft because of the fly by wire system and auto trim function and trimming up/down would disappoint me.

Because it is a common misconception that FBW aircraft don't need trim. If they did not need trim, why have a trim button on the stick? It does have some automatic trim function in pitch, but it does this by g or AOA depending on the mode.

This information is for USAF block 40/42 circa 2009 Digital Flight Control System (DFLCS), block 32 and below uses a different system and this may or may not apply. Digital Flight Control Computer (DFLCC) has change several times and so has its software. This may not apply in different years and different countries.

Depends on landing gear (LG) handle position and in flight refueling (IFR) door position.

 

In cruise gains (LG up and IFR door close)

pitch trim inputs are g command signals identical in function to normal stick pitch commands.

 

With landing gains (or IFR door open)

It uses pitch rate command until 10° AOA, aftrer it does both pitch rate and AOA command

Wheel spin above 60 knots centers pitch trim.

 

Roll and Rudder trim may have to be change during flight depending on conditions and load out. Roll trim command proportional rudder trim trough the ARI. ARI does not work with wheel spin above 60 knots.

That no matter what, someone will not agree with the FM. At some point they need to lock it down and stop changing it no matter what.

Well, there is a problems. Not all block 50 have the same avionics, nor the same systems nor capabilities. If you want accuracy, again, you would have to be specific of the country, year and block.

9 year I have been saying this.

During the climb, what was the G? If it was 1g, the DFLCC is working as I understand it in the F-16, I can't speak for the mirage system.

https://forums.eagle.ru/showthread.php?t=140940

https://forums.eagle.ru/showthread.php?t=211595

https://forums.eagle.ru/showthread.php?t=246228

https://forums.eagle.ru/showthread.php?t=248056

https://forums.eagle.ru/showthread.php?t=251530

https://forums.eagle.ru/showthread.php?t=196974

I told an example. Flying straight and level 0 feet per minute on the vsi and 380 knots. I stop making inputs on the controls (even no joystick connected) and the aircraft starts pulling up slightly, at the same speed that in about 30.seconds my vsi would show at about 500 feet per minute climb.

2 tracks attached to this post.

Some maneuvering it make the FCS/FLCS work, then recover to Straight and Level conditions as you described (except 350 knots).

30 seconds using timer less than 100ft altitude deviation, less than 100 feet per minute vertical speed change (both cases a climb).

EDIT: I didn't touch the trim (in any direction) in either.

F-16 no climb 30sec.trk

FA-18 no climb 30sec.trk

So it did have a small deviation in straight and level.

I tested it on the F-16 and the pitch change is very slight, not noticable but in the Mirage it is.

I wonder if thats the case in the real thing.

Guys i really appreciate the replies and i really look forward to finish my training in the mirage and fly with you Veterans.