More Physics, More Real Winds

Just popping down the shops in my flying… whatever this thing is :thinking: in X-Plane, to get some donuts


I’m not sure how many different ways there are to simulate airflow over a surface, but I believe that XP uses a technique called Blade Element Theory. I’m not sure if any other sims out there currently use this model other than XP.

I never designed a plane in XP, only flew them, but my layman’s understanding of it was you would design your wing shape, and the simulator would simulate the airflow over that wings surface.

The following document, from 2004 goes in to some detail on how FSX does it.

My understand of MSFS was it used some improved model of what is in use in FSX, with more of these “data points”.


Where did you find that? link?

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I never claimed MSFS is using lookup tables, I’m saying it is using the .cfg file for certain things. My point is, the aerodynamics are not solely based on the 3D model like X-plane, it uses the .cfg file for certain things for sure. Is the X-plane approach more realistic? Maybe, it certainly looks and feels more solid and more professional than MSFS at this moment. So far the MSFS default planes have not been a great showcase… Also X-plane is aiming for realism while the MSFS devs have admitted they’ve dummed down certain aspects and try to be the multi-role F35 of flight sims.

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Can see it in action :slight_smile:


Do you mean the purpose of this video is just showing XP11 level of replay system readily available and not present in FS2020 :joy: (sorry can’t resist).

Kidding apart, XP11 is certainly giving me a better sense of flying especially with winds and in VR (see video inside):

[BUG/FEATURE] FS2020 is breaking the VR golden rule: don’t move the camera, the user is

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I suppose, at the end of the day, it really doesn’t matter which approach you take as long as the end result is something that approaches reality.

The merits of each method will come through in development, either helping, or hindering, the development of a plane.


I do find it hard to believe this is not coming directly from a .cfg file. In the real world this would be unflyable.


Yes, that is absolutely correct. I was not trying to insinuate that X-Plane is inherently better per se. If the data for an aircraft is very well researched and adapted to fit the simulator model, you can have great results with the way Microsoft handles the flight model.

Just that X-Plane computes the aerodynamics of an object based on shape, weight, and power instead of looking it all up in some table and applying these values to the rest of the flight model. Which does help with several problems that the Flight Simulator does not address.

But I think the main reason many prefer P3D/FS over X-Plane is the thriving third-party infrastructure. There just seems to be so much more of a market to cater for every type of flying. How many customers does X-Plane have? I think somewhere in the 100-150k range. It’s just not as well adopted and not all of that is due to P3D or FSX being the better sim overall.

The Microsoft offering is somewhat more user-friendly in my opinion. The GUI looks better and everything is quite easy to set up. Trying to break down the argument of “which sim is better” to the flight model alone does not cut it.

Sure, errata in the BET can cause problems, but so can the Microsoft approach. Just look at the flap issues we are currently experiencing. Problems can arise in any complex system.

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Then what does FS use?

Because it sure isn’t the shape of the airframe, because you can make anything fly in FS2020. I linked a flying doughnut, but you can also create a flying Burrito or a flying Pizza. The shape of the object does not matter.

So where does the data for the flight model computations stem from if not from values in a table that someone as derived for the simulator to use?

Honest question, because I can’t think of anything else.


Thanks @LincolnSixE I had to laugh. The video shows very well that X-Plane also only boils with water and there is something wrong with their physics (i watched the whole video). If such vehicles can fly, then the flight physics in X-Plane are not that great either. I have had very bad experiences with the flight behaviour of helicopters and the standard aircraft in X-Plane. That’s why my X-Plane is in the cupboard.

In the end, however, it’s the overall package that counts for me. For example, credible flight behaviour, weather, ATC and scenery. And for me, MFS is far ahead of X-Plane. Of course, MFS has its problems, but in X-Plane I frowned much more often in disbelief.

At the end of the day, everyone has to decide for themselves what they like better. But this “mine is bigger than yours” is just silly.


but MSFS doesn’t solely use lookup tables, it also uses elements of the modal too, likewise X-Plane can have equally silly flying things which were done long before MSFS.

while the flap issue of late in MSFS may be global in a sense that it affects all aircraft, it is actually all aircraft have individually had the errata change, that can individually be changed on the none encrypted aircraft so its not “global” in the same sense as an underlaying BET change that will consequently change all aircraft.

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I never claimed it SOLELY used lookup tables, but it uses them. X-Plane also uses tables for certain things, but not aircraft specific data from what I can gather.

The exact nature of a problem is not that important. Errata can be fixed. If anything is wrong with the BET and has a global effect, the same is true for the fix. Correct the equation, done. Everything falls into place, unless there are errors in other parts of the calculation.

That is actually great if you think about it. Instead of moping around with individual config files you just correct on a global scale. Does not sound too bad to me, but I am not a programmer or an aeronautical engineer.

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Well I don’t see anything that is impossible to fly? Sure if you use text as visual model for a helicopter rotor it looks weird. But behind every single one of those there is a plausible model, but maybe not always correctly represented visually.


Could you expand on that, as you seem to have the insight?

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You really don’t see that? If the flight behaviour should be based on the 3D model, then this vehicle should not fly. But quite honestly, I find the whole discussion here completely absurd.


Couple of things that have been neglected.

  1. The concept of calculating flight physics based on model shape.
    Anyone that has ever created a 3d model on computer knows that there is a a visual model and a physical model. The wireframe, physical model is what is used to create the physics of the object. It is not visible until a surface has been applied and a texture added. I can quite easily create a physical model of an aircraft and overlay a visual donut if desired. That is why we can have odd shapes fly in any flight model.

  2. A configuration file does not preclude the use of surface dynamics.
    Any model that uses complex equations to achieve a simulation of dynamics can be manipulated using variables. Einstein was unhappy with the math in his relativity computations and so Lambda was created as a cosmological constant that manipulated the equation to change the outcome. It is entirely possible to have the flight dynamics equations contain variables that can be changed in a .cfg file to allow for making adjustments from the base math. I don’t know if XP has an exposed batch of variables but it would make sense that aircraft designers must have a way to make adjustments to their designs without having to access the base flight dynamics of the sim. It is through the exposure of those variable that we have a cfg in MSFS that allows for tweaking individual aircraft behaviors.

  3. Not one person here, myself included, has any idea how the various flight dynamics models achieve the end results.
    We are using a combination of observation, our knowledge of real world aeronautics and pure conjecture to argue which invisible unknown is better. When we are done here we should start another thread to debate whether phasers or disruptors would be the ideal weapon for use during a starship battle in an ionic storm.


Going fast enough it would fly, it has rocket engines apparently :joy:. But anyway, the model itself might not be the same as what is represented visually? I’ve also seen a helicopter rotor represented by a string of text :sweat_smile:.


I you want to experience really great flight dynamics in GA aircraft get A2A.

And after this statement by Scott Gentile I can’t wait for them to come to MSFS

We are committed to Prepar3D as this is the best commercial training platform available. FS2020 is what we see / hope is the future for the public, just like FSX was. We’re building even more of our Accu-Sim technology outside the host simulator (P3D, FS2020, etc.) so starting with our next release we will be even more platform independent than ever. This way, regardless of where the winds blow in terms of the platform of choice, A2A’s entire library will be nimble and moveable without compromising the core aircraft.



So you didn’t watch the video after all? The green things are floats and it takes off from the water. So you can also fly a donut in X-Plane.

As I said, this discussion is just too absurd for me. I will not comment any further on this thread and will only read along with a grin. I also don’t count myself among the simulator warriors who have to defend their sim to the knife. If I want study levels, I fly DCS. If I want to relax, I fly Flight Simulator. If I want to shake my head in disbelief, I fly one of the standard planes in X-Plane.