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dts1

X-Plane 11 Taildtagger & Stinson erratic absurd ground handling

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The censored discussion going on in "Questions" at the X-Plane forum is about the comical erratic ground handling of all Taildraggers including the simulator's own Stinson, exacerbated and essentially becoming unuseable in even mild crosswinds. Certainly worthless for anybody attempting to learn or maintain taildragger skills and proficiency. I am a private pilot with tail dragger experience, which I would have liked to refresh with X-plane 11. One of the major reasons (I'm sure I am not alone) for my purchase of X-plane 11 was to get the most realistic taildragger modeling using propwash over the elevator and rudder.

A2A accu-sim planes in FSX come closest to reality, but I thought X-plane would be the pinnacle for those embracing vintage taildraggers. I am SORELY disappointed.

Here is a person who made a Youtube video of his initial shocked experience and the absurdity of the X-Plane 11 Stinson erratic ground handling. This is even NO WIND. This faulty behavior is inherent in some degree to all X-plane taildraggers.

https://www.youtube.com/watch?v=P0duuqbmr4o

I guess like so many others that have complained in the "Questions" forum and over at Aerosimgaming, I was SUCKERED in by X-Plane's claim of being the most accurate flight simulator.

The have a pat answer to all requests for a fix;

"X-Plane has pilots on the team, but none of them fly many tail draggers. In general, Austin uses his experience to tweak the flight model. If people can provide enough specific information, gathered from very controlled experiments & real life, or from official documentation such as the POH, we will be able to use it to adjust the flight model as well. The only tail dragger we have in the default fleet is the Stinson, so that would be a good aircraft to do any tests with. In general, Austin codes the flight model based on his experience in very carefully controlled conditions. If his experience doesn't cover an area (like tail dragger aircraft) the flight model may not be tuned exactly right.

We hear complaints about tail dragger aircraft occasionally but have not yet gotten the type of data he needs to make changes. He will be looking for very specific mathematical proof to tweak the flight model for these aircraft. If anyone has specific data they should submit it via the bug reporter."

FLIGHT MODEL NOT TUNED EXACTLY RIGHT ???? The UNDERSTATEMENT of the year. What hubris!

They essentially admit that they do NOT KNOW WHAT THEY ARE DOING and it is up to you the suckered in purchaser to tell them what is wrong with their blade element flight model code and supply mathematical proof??

That is about the last straw for an X-Plane 11 purchaser's wasted money!

My CENSORED response to this outrageous incompetence ---

"The X-plane taildragger flight model failure has been around FAR TOO LONG.

Why don't you quit flubbing around with this fundamental problem and hire a well known professional pilot like
A2A's Dominique Henriques, or well known professional flight model tuner like Bernt Stolle who could instantaneously
educate and clue you to the failures of your flight model, from which you could then decipher and link to your failed coding! This would be of enormous benefit to the quality of your product and boost it to the undisputed most
accurate available for any aircraft rather than an enormous disappointment!"

Not to mention allowing taildragger customers a return on their money!

 

 

 

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@dts1,

for best ground / air physics model, use IL-2 Battle of Stalingrad please... Rest is ... Well...

DCS good too, but IMO not as good as IL2.

X-Plane's ground physics are bugged to the top, useless as much as FSX's are when it comes to proper use of rw techniques... so, believing FSX does a better job is, after all, naïve.... sorry :-/

It's probably the wind effects and how they're modeled, but it's also the transition from stopped to moving and slow / fast on ground that Austin himself has acknowledged to be far from perfect and requiring attention... 

Maybe for XP12, one never knows....

Some add-ons try to get around the limitations and create some really imaginative solutions. I remember one being a recently released Corsair F4-U for XP11 which I really enjoyed a lot more than usual taildraggers I had tested in XP. The author added an invisible ventral skid to increase stability and make the whole behaviour a lot more believable, even if not totally convincing...

Edited by jcomm
  • Upvote 1

José Uninstaller da Silva, happy again with:

~\ô/~ P3d v5.2 HF2 + Orbx Global / Freeware Airports enhancements + FSLabs A319/20 + PMDG 777 200 LR

 

 

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The ASDG super Cub, has pretty good tail dragger qualities. Although I am not tail dragger qualified I have seen several pilots familiar with the Super Cub to be quite happy with their model. I like it although it is too hard to start in my opinion. 


Donald E. Donovan

Flying is the 2nd greatest thrill known to man

The 1st is landing.

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Laminar Research jumped on the VR bandwagon with gusto. It would be nice if they would get the take-off torque, ground handling and aerodynamics straightened out with the same intensity. If it is to be the most realistic flight simulator, these problems have to be fixed.

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Jim Morgan

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11 minutes ago, jcjimmy said:

Laminar Research jumped on the VR bandwagon with gusto. It would be nice if they would get the take-off torque, ground handling and aerodynamics straightened out with the same intensity. If it is to be the most realistic flight simulator, these problems have to be fixed.

Yep, pretty much, but to me it appears it's lost in as far as any fine tuning goes in those areas for the rest of the XP11 cycle... They're up to VR tuning and that's probably about all users can expect - not me really who couldn't really care less about VR...

Then, XP12 will come, announce the Ultra-Realistic flight dynamics, Austin will add a new "feature" to the engine model or the flight dynamics ..., new bugs will join the party... and the cycle starts again - it's X-Plane : accept it as it is, and enjoy, or ... leave ( that's what I always end up doing... after a while )


José Uninstaller da Silva, happy again with:

~\ô/~ P3d v5.2 HF2 + Orbx Global / Freeware Airports enhancements + FSLabs A319/20 + PMDG 777 200 LR

 

 

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"Prop Wash" - over the tail surfaces (vertical + horizontal) is, of course, thrust but not necessarily what provides control.  "Airflow", generated by that thrust, is what the elevators and rudder need.  Several WWII era jets were taildraggers with minimal prop wash and they managed to stay straight on takeoff because of sufficient airflow.  I oftened wondered how a little GE J610 would have been on my Pacer.  Plenty of thrust, no prop wash and lots of control effectiveness - not so much after they broke off :blink:.  Stick your hand out the car window and watch it fly with no prop wash.

Edited by olderndirt

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I have the same problem with any of the tail draggers, even worse if there is any wind to the point I just don't fly them.  The torque is ridiculous and NOTHING like real world.  How the aircraft reacts to moderate winds (5Kts or less) is not accurate at all.  I hope LR take a serious look at their much touted Blade Element Theory and all that goes with it ... in some situations it can work really well (turbo props for example), but in the important and critical situations is just WAY WAY off reality. 

There have been some creative solutions (as pointed out) to work around the physics problems.  Personally I'd almost rather have no physics than physics that are way off ... real world flying is SO much easier.

Don't get me wrong, I love XP11 and I love P3D, but there are days when I go ... "you've got to be kidding me" (on both platforms) and go fire up Civ VI and relax.

Cheers, Rob.

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4 hours ago, jcomm said:

@dts1,

for best ground / air physics model, use IL-2 Battle of Stalingrad please... Rest is ... Well...

DCS good too, but IMO not as good as IL2.

 

You are kidding me? DCS is great but their interpretation for example of Spitfire even more bizarre

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flight sim addict, airplane owner, CFI

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It's a nice video, and indeed one can control any aircraft in X-Plane, just not in a realistic way because, I am sorry but, ground physics are really bugged ... and Austin knows and admitted it ...

Add to the equation some wind, and yes wind can be tricky IRL, and try to apply the usual techniques, depending on from where the wind blows while you're taxiing, like for instance in the bellow video recorded by in IL2, and... it'll be more than evident that something is really in need for attention...

Some aircraft apply typical tricks based on Art Stab or invisible wheels, carts, skids... but well, it's not right ....

And I find that IL-2 is also a tad too sensible to winds on ground than it should...

 

https://www.youtube.com/watch?v=C4-TvPxLioY

Edited by jcomm
  • Upvote 1

José Uninstaller da Silva, happy again with:

~\ô/~ P3d v5.2 HF2 + Orbx Global / Freeware Airports enhancements + FSLabs A319/20 + PMDG 777 200 LR

 

 

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For one thing, the default L5 Stinson was made in an older version of PM and so is not as affected by the changes in ground physics and propstream, etc and Austin has mucked up.  So you picked an easier plane to fly than most of the payware newer planes that everyone is complaining about.

Second, I DO fly taildraggers a LOT, and not only the Chief.  And I can tell you that the ground handling in XPlane and the behavior of the planes in crosswind conditions are NOTHING like they are in real life.  If I flew my plane like I have to fly the aircraft in XPlane in order to control them acceptably, it would be a burning hunk of fabric and metal.  And if I try to fly the taildraggers in XPlane as I fly real taildraggers in real life, they are uncontrollable.  

Third, landing is of course easier than taking off because your prop is at idle and so the crazy prop effects and gyro effect dynamics in XPlane are not as much in play.  And the screeching is an indication of the fact that the plane is not behaving as it should be and that the physics are wrong.  It's not a bug, except in the sense that the underlying physics are certainly seriously bugged.  You get the screeching because the ground/flight dynamics are putting ridiculous side loads on the wheels, which if it happened in real life every landing like that, would mean replacing tires and perhaps the whole gear structures every few landings.  

There are a lot of things that Xplane has gotten very right in terms of flight dynamics and physics.  The ground physics, and the p-factor/gyro effects and prop flow on tail services are VERY WRONG.  The physics are NOT CORRECT.  They are not even close.  

And DCS does indeed largely do a MUCH better job at modeling flight dynamics in these areas, and several others as well.  

@jcomm: do you mean too "sensible" in IL-2 or too "sensitive"?  In my opinion, it's a bit too easy to control the planes in IL-2, both on the ground and in the air.  Doesn't detract from it's great fun, for me at least. 

Edited by Griphos

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5 minutes ago, Griphos said:

 

@jcomm: do you mean too "sensible" in IL-2 or too "sensitive"?  In my opinion, it's a bit too easy to control the planes in IL-2, both on the ground and in the air.  Doesn't detract from it's great fun, for me at least. 

I meant "sensitive".

IL-2 did tune down the physics in the latest patch. IMO it was a wrong option, but it is meant to be easier for those without good hardware or more interested in the combat aspects and getting airborne and then land asap, without much trouble...

In X-Plane some aircraft ( XP11 ) can really give a good feel of ground physics within the limitations imposed by the underlying platform. Of the few add-ons I own I remember the Grumman Traveller AA-5, and recently a Corsair ( F4-U ) I bought and really enjoyed in as far as ground physics go...

Even the MDLAG 109s are nicely tuned - specially in the latest version. I'd say that it behaves regarding ground physics more plausibly than the 109s in either IL2 or DCS, less when you add power for takeoff :-)


José Uninstaller da Silva, happy again with:

~\ô/~ P3d v5.2 HF2 + Orbx Global / Freeware Airports enhancements + FSLabs A319/20 + PMDG 777 200 LR

 

 

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1 hour ago, Griphos said:

For one thing, the default L5 Stinson was made in an older version of PM and so is not as affected by the changes in ground physics and propstream, etc and Austin has mucked up.  So you picked an easier plane to fly than most of the payware newer planes that everyone is complaining about.

Second, I DO fly taildraggers a LOT, and not only the Chief.  And I can tell you that the ground handling in XPlane and the behavior of the planes in crosswind conditions are NOTHING like they are in real life.  If I flew my plane like I have to fly the aircraft in XPlane in order to control them acceptably, it would be a burning hunk of fabric and metal.  And if I try to fly the taildraggers in XPlane as I fly real taildraggers in real life, they are uncontrollable.  

Third, landing is of course easier than taking off because your prop is at idle and so the crazy prop effects and gyro effect dynamics in XPlane are not as much in play.  And the screeching is an indication of the fact that the plane is not behaving as it should be and that the physics are wrong.  It's not a bug, except in the sense that the underlying physics are certainly seriously bugged.  You get the screeching because the ground/flight dynamics are putting ridiculous side loads on the wheels, which if it happened in real life every landing like that, would mean replacing tires and perhaps the whole gear structures every few landings.  

There are a lot of things that Xplane has gotten very right in terms of flight dynamics and physics.  The ground physics, and the p-factor/gyro effects and prop flow on tail services are VERY WRONG.  The physics are NOT CORRECT.  They are not even close.  

And DCS does indeed largely do a MUCH better job at modeling flight dynamics in these areas, and several others as well.  

@jcomm: do you mean too "sensible" in IL-2 or too "sensitive"?  In my opinion, it's a bit too easy to control the planes in IL-2, both on the ground and in the air.  Doesn't detract from it's great fun, for me at least. 

Well, I haven´t flown taildraggers in real life - but if you really want something to change in the way they are portrayed in X-Plane, you need to be more precise than "the behaviour is wrong". I have read up on taildraggers behaviour, and I can´t see anything "wrong" in a qualitative way with the way X-Plane portrays them. Sure, the quantitative side of the mentioned effects is probably off, but neither ground handling nor taildragger handling is fundamentally flawed (in the sense of the word).

Are there any laws of physics getting violated? Are there any forces applied in the wrong direction? These are the kind of questions that will sway minds at Laminar, not some anecdotal evidence beefed up with an "its all wrong, I tell you!!".

I have checked the bug database at Laminars and the last complaint about taildraggers being not right was from late 2016. So either its not as bad as you lead us to believe, or people aren´t reporting it.

The wheel screeching is a different matter, quite a few reports about that. Again, nothing fundamentally wrong with that - just quantatively.

Jan

 

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5 hours ago, Janov said:

Well, I haven´t flown taildraggers in real life

I should probably just leave it there, since that says all we need to know.  Typical forum "expertise" arguing with actual experience...

I'm not trying to get anything changed in this thread.  No one from Laminar will ever see this thread.  I'm speaking to you, not Laminar.  You're the one who claims in your video that the physics are "correct."  You, who not only have no taildragger time, but also have no real knowledge of either physics or the code of Xplane.  So, I'd say that I'm at least one up on you in terms of expertise.  I, at least, have the taildragger time to tell you that the "physics" of Xplane are indeed, NOT "correct."  I'm telling you from direct experience that the representation of ground handling is indeed fundamentally flawed, and I'm telling you which dynamics are responsible.  I said a lot more than "it's wrong."  And where do you get off telling me that I'm not allowed to make that claim without some particular sort of evidence you say is required to support it while you make the opposite claim without any evidence whatsoever, including no actual experience (other than "reading up" on it)?  

You do understand that the term "physics" is a term of art, right?  This is coded software, not the real world.  You can certainly attempt to code in order to make the pixels you move around the screen appear to obey the "laws of physics" more or less well, but it isn't actually simulating physics in any direct sense.  The only "laws of physics" that are operating are the laws of light propagation.  

The Laminar bug database is tricky to use to find how many reports have been made on many issues, since people use a lot of different terms to file those reports.  Try reading the actual Xplane forums, perhaps.  You'll see a LOT of detailed complaints about the ground handling and the new slipstream effects.  I don't know if the coded algorithms makes sense or not (and neither do you), but I can tell you that the geometry of the way the wind and wheel friction and lever arm moments in the sim move some of these aircraft are an absurd representation of those in real life.  

But it is unlikely that anything will be done about it, since actual developers have been in fairly lengthy conversation with Austin about it for some time now without any clear result.  

@jcomm:  I've heard the 109 in Xplane is a pretty good handling plane, and it's not clear how the developer has achieved that in his recent update, except that he has made a point of saying that it's all in PM.  He has no external plugins handling anything.  It would be nice if he shared his secrets with some of the other devs.  I've been waiting for Pete to finish the Beaver update, but he appears to be making very little headway overcoming the new dynamics that have screwed the Beaver's handling up so very badly.  

Edited by Griphos

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6 hours ago, Janov said:

Well, I haven´t flown taildraggers in real life

Let me see if I can explain this to you clearly. 

In a flight simulator, what should happen is that, using your computer hardware, you should be able to make control inputs just the same as you use or would use in a real aircraft, and the virtual airplane should respond to those inputs in just the way the actual airplane would respond.  ANY divergence from that is a problem.  A large divergence from that is a big problem.  Xplane has a very big problem using that standard when it comes to ground handling and cross-winds and when it comes to taildragger aircraft and the dynamics of gyro effect and p-factor and prop slipstream across tail flying surfaces, all of which come into play when you add thrust and change the attitude of your aircraft and the precession of of the plane of the prop disk when lifting onto the mains or rotating.  

Anything else (including techno-babble about the underlying theory of the software modeling of the "physics") is just moot if you can't achieve the above criterion of faithfully modeling what an actual plane does in a given situation.  This isn't a classroom exercise or thought experiment.  It's a simulator.  It should simulate correctly, or all of its underlying "theory" is rather beside the point, now isn't it?! 

 

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