F-15/A-10 Rolling when applying rudder

[TimeStreamer]

Hello people.

 

Although I'm a fan of FC series since the beginning, I confess I lack the knowledge to determine if this really is a bug or not. So can please someone enlighten me at the following:

 

I've not played FC3 for some time now and when I made the update to 1.5.5 my F-15 and A-10 start rolling when I apply some rudder. It's not a smooth thing. It rolls like I'm doing full joystick left/right. It is not a joystick/axis issue. My warthog works fine in other games, and in other planes too, like the Su-27, Mig-29 or even Mirage 2000. I've also disconnected it and use default keyboard settings. It does the same pressing Z or X. I also made sure everything was by default at the axis configurations.

 

It's been hard to me to use rudder to make landing adjustments or to align cannon shots, since the plane rolls instead of applying the usual left/right kind of "strafing".

 

It's also not related to CAS settings as two other people already pointed to me. Enabling/Disabling CAS with Ctrl+1/2/3 DOES NOT solve the issue. Never saw any sim doing this, neither DCS did it before this version at least.

 

Is it working as intended, is it a bug or there is some new feature I have to turn on/off ?

 

Thanks in advance. Cheers.

[razo+r]

Those are normal physics

 

Su-27 rolls when applied rudder

MiG-29 and Su-33 have SFM so it's not moddeled there

Mirage has a FBW that compensates that

 

You shouldn't use full rudder on approach, even better is to not use the rudder at all, you need practise to do an approach without it, or just simply compensate the roll

 

and you can easily compensate full ruder with your ailerons, no matter if you're at 200 or 500 knots or at 1000 feet or 20'000 feet, i extra tested it for you

 

the CAS doesn't compensate, it's only for applying the optimal surface control

 

Those are physics, not a bug and so you can't turn them off

Edited December 13, 2016 by razo+r

[Pocket Sized]

Yep. When you apply rudder only, the outside wing will move faster and produce more lift (I'm pretty sure there's more to it than that but you get the idea) especially on aircraft with longer wings (A-10 for example)

 

Rudder is usually used in conjunction with aileron to keep you coordinated, but modern military aircraft (F-15, A-10C, etc) have stabilization systems that do it for you.

 

A real A-10C pilot is quoted as saying he never used rudder to line up strafing runs, just small roll corrections.

Edited December 13, 2016 by Pocket Sized

[Exorcet]

my F-15 and A-10 start rolling when I apply some rudder.

This is normal. The wing on the inside of the turn should dip as you yaw because it sees a lower airspeed than the outside wing. If the plane rolls in the opposite direction, there may be a problem.

 

 

It's not a smooth thing. It rolls like I'm doing full joystick left/right.

That sounds excessive.

 

Are you able to post a quick video showing the issue? If you roll in the opposite direction, can you over come the yaw induced roll?

[TimeStreamer]

Talking about physics, all you guys say makes sense to me. As I apply rudder, the plane rolls since it air flows faster in one wing. Regarding that, it's OK then. I don't see a problem if it is accurate.

 

But:

Su-27 rolls when applied rudder

Then why my FC3 SU-27 works 'fine'?

 

That sounds excessive.

Are you able to post a quick video showing the issue? If you roll in the opposite direction, can you over come the yaw induced roll?

 

I'm not able to post a video now since I'm at work. I can do one once I arrive home then post it here. If I try to compensate the roll the plane behaves awkwardly. Best way to describe it is that the planes struggles to roll to both sides. I will not get into details here because it could be me not doing things right. I will try to do it on the video.

[razo+r]

If your Su-27 isn't rolling with rudder (slowly, not like the F-15) then you either doing it wrong or have some kind of input in it that compensates it, your using the Su-33 or you have messed something up in the FM

 

Also, describe what you mean with: 'fine'?

 

And if you compensate for the rudder input, it does feel a bit odd, the struggeling to go to both sides is that you haven't been able to hold the balance, if you get it right, it won't move at all(besides drifting to the right)

[TimeStreamer]

"fine" meant as it was supposed to be from my initial point of view: doing yaw with no roll.

 

And yes, as I stated before, it could be me not doing things right.

[LJQCN101]

Real life video of a F-16 kicking rudder to the left:

 

Being a 3-axis FBW, it does compensate uncommanded roll to a degree, but not that much. (Just one example.)

Edited December 14, 2016 by LJQCN101

[Emmy]

Leveling the wings with rudder is something you're taught while learning to fly in real life.

[TimeStreamer]

Yesterday I've made a quick video of my issue but it turned out to be a 1.2Gb file. Preferably I would do something smaller to upload. I've also launched DCS in a quick SU-27 intercept. It turned out to be that I was wrong. After holding rudder left or right for some time, I've realized the plane rolled slightly to the same side. The roll rate is much smaller than the F-15 or the A-10, but the plane actually rolls, as many of you already stated. As such, I do believe everything is A-OK and this is probably a non issue, since, as razo+r wrote earlier, the F-15 is supposed to roll faster than the SU-27. The F-16 video was a mind changer too. Thanks guys. I will post a link of my video anyway. Well, I have to practice more then. :doh:

[Nerd1000]

Yesterday I've made a quick video of my issue but it turned out to be a 1.2Gb file. Preferably I would do something smaller to upload. I've also launched DCS in a quick SU-27 intercept. It turned out to be that I was wrong. After holding rudder left or right for some time, I've realized the plane rolled slightly to the same side. The roll rate is much smaller than the F-15 or the A-10, but the plane actually rolls, as many of you already stated. As such, I do believe everything is A-OK and this is probably a non issue, since, as razo+r wrote earlier, the F-15 is supposed to roll faster than the SU-27. The F-16 video was a mind changer too. Thanks guys. I will post a link of my video anyway. Well, I have to practice more then. :doh:

The huge file size is happening because you're recording in an uncompressed video format such as .MOV, .MKV or .AVI. If you can, set your recording software to use .mp4. Otherwise download Handbrake (a free and open source video format converter) and set it to convert your video file to .mp4.

[GGTharos]

There are additional parameters that may or may not be modeled - for example, rudder inpot at very low or 0 AoA should give you all yaw and almost no roll.

 

At negative AoA you might get yaw and roll in the opposite direction that you would expect. Depends on the airframe as well.

 

"fine" meant as it was supposed to be from my initial point of view: doing yaw with no roll.

 

And yes, as I stated before, it could be me not doing things right.

[LJQCN101]

Classically you would need wind tunnel test data to determine whether you've got a reverse control.

 

To determine the effect of rudder in a variety of AoA & sideslip regions, you would need Cl, Cn tables of the aircraft itself which reflects lateral and directional static stability, and the Cl-rudder and Cn-rudder table to evaluate the additional roll and yaw momentum generated by rudder alone.

 

In a F-16 for example, lateral and directional static stability seems to be symmetrical between -20 and 30deg AoA. And from Cl-rudder and Cn-rudder table, reverse control can be observed the following regions:

 

 

 

So somewhere between -5 and -10 AoA, with sideslip larger than 6 degs, Cl generated by rudder and by the aircraft itself have a chance to compensate each other, resulting in little roll or opposite roll. Yaw direction will not be changed under negative AoA.

Edited December 15, 2016 by LJQCN101

[The_Nephilim]

Well for me the problem was when I loaded the HOTAS files for a profile the Axis was assigned to the rudder..

 

I would go into options in DCS and make sure the Rudder is not assigned to a Axis keypress by mistake..

 

This happens to me when installing HomeFries profile and he said it was a side effect of DCS..

[Mars Exulte]

The FC3 aircraft all used to have simplified flight models. They've been going through bringing them up to Professional level, as with the other aircraft. Although the systems are still simplified (no clicky cockpits, etc) the aircraft themselves are not any longer and behave more realistically. As others noted, two of them are still being updated.