Aircraft keeps rolling....!

[patrickpilot 0]

Hi Flight Sim Friends,

 

So I'm currently working on my Private Pilot License, training with a Cessna 152.

 

To repeat and "keep my brain active" I use X-Plane with the Saitek Cessna Yoke.

 

Everything works pretty ok.. I mean it's of course not that 100% reality feeling, but it's ok.

 

The only thing, that drives me crazy is the constant roll. I don't mean any torque or p effects.

 

What I mean is the constant roll into one direction as soon as I move the yoke to the left or right.

Even if I center the yoke, the aircraft keeps rolling into the initial direction.  To counteract this, I need to move yoke slightly to the otherside, just to center the aircraft.

 

This is not needed in a real aircraft. Do you have any idea? I've already tried all the options in Xplane, but nothing seems to help...

Eventually somewhere in Plane Maker?

 

PLEASE HELP!!!

 

thank you and best regards,

patrick

[tkyler 88]

This is not needed in a real aircraft.

 

X-Plane is not a real aircraft.  X-Plane is a idealization of a much much more complex aerodynamic phenomenon.  Combine this with a joysticks poor precision compared to reality...spring loaded self-centering and lack of feedback over its real counterpart, you will never get that "neutral feeling" you get in a real airplane.....in real aircraft you make frequent adjustments, I guarantee it.  I also guarantee the stick in a real airplane is not 100% ridgly fixed in the exact same position for periods of time like a joystick is when its self-centered  with springs. 

 

The best you can do is trim the aircraft in x-plane and make periodic adjustments with the joystick.  Now that being said, the flight model of the aircraft you are flying, as set up by the author also has something to do with it....if the Cg of the flight model is too high, it will tend towards instabilty and roll more than it should.  Lowering the center of gravity of the model can help.  Most aircraft authors have no clue as to the real vertical Cg location of aircraft so sometimes you have to guess and sometimes the guess is no good....but that still will not alleviate roll completely for single engine or "same direction" prop twins.  Just as you keep you fingers "on" the real yoke and tweak even so slightly...so must you do in x-plane. 

 

Maybe its just me, but this guy never keeps the yoke centered for more than a half second, no matter where in the flight regime he is.  I challenge you to find a video where the yoke stays as steady and centered as the one on your desktop.  Keep a sharp eye on the yoke all throughout the video! 

 

 

TomK

[LHookins 3,102]

 

 

What I mean is the constant roll into one direction as soon as I move the yoke to the left or right.

Even if I center the yoke, the aircraft keeps rolling into the initial direction. To counteract this, I need to move yoke slightly to the otherside, just to center the aircraft.

 

Yeah, I get that all the time.  In a spacecraft in orbit.

 

Tom, are you saying that this lack of roll stability is intentional?  This is the first I've heard of it.

 

Hook

[tkyler 88]

Very few people agree with me on this one.  My contention is that the rigid environement of the simulator....the super perfect joystick position, the lack of turbulence simulation in x-plane (the aerodynamics are too complicated) results in a very "rigid solution" of mathematical forces on an aircraft where a net roll force of zero just won't be attained...meaning mathematically there will always be a roll in some capacity.  I have balanced forces on a flight model such that I can go perhaps over a minute with hands off and not roll more than say 5 degrees but this is beyond realistic as I contend nobody in the real world lets go of a yoke for 60 seconds without autopilot.

 

In videos, you can see non-stop twitching and correcting of the yoke on most every small aircraft....so you can't say planes are neutrally stable and can be flown 'hands off'...IMO, they just can't; however, joysticks have this spring loaded self-centering mechanism whereby you have to exert x force for small adjustments...and in a real plane that force tends to be much less, or perceived as less due to force feedback.  You may be "holding" a yoke level while the plane is attempting to roll and move the yoke so in a real plane you perceive it as "pressure" but joysticks have no such pressure.  So in a real plane, you make these super minute movements to keep the plane level without even thinking about it whereas on the simualtor, you hvae to hold the joystick over a small amount and this spring force you have to overcome from neutral makes your hand tired as you have to "hold" it there and you think, "this just isn't real"....and that I would agree with.   But that's a limitation of desktop simulation.  Expecting desktop simulation to capture the finer nuances just either side of a level flying airplane  with all the little turbulence bumps or super small corrections we make automatically.... just isn't captured with today's tech.    The video above is a great indication of how the pilot just simply "reacts" an doesn't thiknk about it.  He never stops flying the plane.

 

TomK

[LHookins 3,102]

Tom, do you have much stick time in a real aircraft?  Got a PPL?  Ever taken lessons?  Just curious.

 

Hook

[patrickpilot 0]

Thanks for your reply!

 

As I'm flying a real aircraft, I know that those "mini reaction movements" are normal. My problem is, that in X-Plane, the aircraft "falls" to the left, as soon as I move the yoke to the left. The roll even accelerates.. This doesn't happen in a real aircraft under normal conditions.

 

Is there any setting somewhere, to prevent this???! Seems like I'm not the only one who has this problem..

[Macpah 46]

Yes, small corrections with the yoke or stick, but because of some turbulence.

In calm air also small airplanes fly remarkable stable.

 

Also, I have this small aircraft in mind, which can be fitted with a electric rudder trim.

If the real aircraft would behave like the X-Plane counterpart, I would rather want to have aileron trim on that plane,

which the real one doesn't have and neither needs.

 

Tom, I agree with you that flying a real airplane feels very different, and that you don't think about how far you move the stick/yoke instead you just feel the pressure and that pressure feels so different, depends on the airspeed and just gives the right feedback to fly the aircraft in a natural and precise way.

It's just not comparable to the plastic spring loaded joysticks and yokes we have at home.

But to me that roll du to torque in XP is something else....

My stick at home has a very light spring force, but the roll due to torque would still annoy me(I use the SASL torque fix)!

 

-Marcus

 

[jcomm 5,889]

I gave up on this...really ... it's pointless to discuss this subject when some of our interlocutors haven't even ever flew a prop aircraft or have a pilot license.

 

The OP, starting his pilot training in RL, has pointed out some aspects that I have seen commented by others. Just like him, they feel something is wrong

overall with prop aircraft in X-Plane 10. I take his observations as rather valid, just as I did take Alec's observations, and am thankful for the fact that he was

really the first X-Plane user who had success turning Austin's attention seriously into this problem with the X-Plane way of modeling prop effects.

 

I believe the same problem, in it's core, does account for the poor ground behavior when there is some x-wind component...

 

I know where to find the most close to real reproduction of a Cessna, Piper, Beechcraft... so, when it's time to have a session of more "serious" simulated flight

and practicing some IFR training scenario, I know what simulator to start, and it really isn't X-Plane or FSX...

 

If I want to play for a while, or show to my friends how beautiful flight simulators are and flying is, looking at the World from above, and that aircraft are great machines

that can do crazy ( irrealistic in the sim most of the time ) aerobatics... I could probably better use MS FLIGHT ( but I have uninstalled it long ago ), FSX with ORBX FTX, and X-plane with some

great sceneries, specially at night...

 

Tom has, as far as I know, a pilot license, so I am sure he knows real prop aircraft do not fly like, for instance, his great MU-2 - no way!

 

Even Austin finally recognized something was really wrong when he recorded that video on his aircraft, and someone commented what he was not doing right ( he had his feet on floor )

and thus was causing a yaw-induced roll, and not a torque-based roll...

 

I will wait for 10.30. If this is not fixed, I will simply keep using X-Plane 10 for a nice night landing, here and there, and wait for something really encouraging in terms of flight dynamics

for future versions...

 

As most of you know, I tried hard to explore alternative "fixes" to this problem, such as artificial stability... but a Cessna or a Piper where Art Stab are used to try to overcome the

irrealistic rolling tendencies, or a twin where the props are made to turn in opposite directions when the real one is not built that way, aren't simply natural and acceptable solutions,

at least for me! And, please don't tell me to use aileron trim, when the real counterpart of the model I am using in the sim was never even built with such...

[Murmur 3,941]

Even more pointless since there is NOBODY here (except Tom Kyler who has his peculiar point of view) that does not acknowledge that there is a torque issue in X-Plane flight model. So there's nothing to discuss really...

 

[LHookins 3,102]

Even more pointless since there is NOBODY here (except Tom Kyler who has his peculiar point of view) that does not acknowledge that there is a torque issue in X-Plane flight model. So there's nothing to discuss really...

 

Well, that depends.  If you have a flight sim developer who has limited experience in real aircraft, and you try to discuss differences between the real thing and their simulator, they don't like it.  They'll argue.  They get upset.  It's not pretty.  This happens even if what you're discussing isn't a criticism.  There are remedies for this.

 

If, on the other hand, the developer has a lot of practical experience (not just book learning), he can discuss these issues without problems... usually.  If the sim is well modeled, then the problem is usually a controller issue or the user expecting one aircraft to perform exactly like another similar one when in reality they're quite different.  These can be addressed.

 

Sometimes a flight sim is a bit unrealistic to simplify the experience for whatever reason, even for veteran pilots.  This can be a valid design decision and I do not take issue with it.  Sometimes these factors actually make the aircraft more difficult to fly than is necessary (and I'm not talking about XPlane here; I've got some first hand experience with a different flight sim) and when egos start getting in the way these things can be very difficult to overcome.  Developers can get really defensive about their baby, even when no argument or criticism is intended.

 

So, depending on Tom's answer to my question about practical experience (rather than just book learning), I can either say, "Good luck" and crawl back under my rock, or offer a few suggestions to help.

 

Hook

[Murmur 3,941]

Hook, I was not referring to you, and I agree with what you said. :smile:

[LHookins 3,102]

I know, I just used your post as a springboard. 

 

Hook

[tkyler 88]

For the record I have about 500 hrs stick time.   A flight simulator implementation combines knowledge of flying and book learning, specifically flight mechanics, flight physiology (to understand the relation bewteen what your eyes see and your body "feels"), programming, numerical methods AND instrumentation (as a joystick is exactly that).   I'm done discussing it here.  You guys go fly and have a good time!

 

TomK

[LHookins 3,102]

 

 

I'm out!

 

In that case, Good Luck! 

 

Hook

[Humpty 751]

LOL i had that problem and one of the members I think Murmur suggested using the trims rudder / aileron and  she is ok, I just need to trim. I would not know if this is there in a real aircraft but the Socata 893 has rudder trim, but I have not seen the aileron trims in her pit. She used to constantly bank left and I could never fly straight and level after settings trims on the gamepad I can fly straight and nice,