More Physics, More Real Winds

I ran an image search, and that image only pops up in a single thread.

I couldn’t see anywhere that indicated where that image comes from.

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Yes its for the wrong engine model, one of the two options (don’t know which one) has TPR gauges instead of N1. Next question will be, what Boeing 787 model? the -8, -9 or -10? They are only speaking about “the B787”, cool, which one :sweat_smile: :joy:.

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Thank you Nijntje, for your high class investment in improving my understanding.

Even if you take a typical engine, or all different engines, the Fuel Flow should not be 8-12% different, It should be 25% and above, which ever engine you take, Boeing will have mostly the performance be 3-4% difference between different engines. The Flight model has only 8%-13% difference, not 25% and above. If the performance difference would be 18 or 20% then I would consider it.

I’m not saying you are wrong, but there are way more variables having an influence on engine performance and fuel flow. Starting with the correct aircraft type (787-8 / -9 or -10) and engine model (RR vs GE), then there is cruise technique (Mach No., cost index), pressure altitude, Static Air Temperature (SAT) aircraft weight, but also CG position.

I doubt the MSFS flight model is accurate as it is very much a work in progress, and for the 787 there is no possibility to even mod the flight model as I understand as it is encrypted. we already concluded that performance is influenced by the aircraft weight for a start. If you want to make any objective comment about the flight model (as I have done numerous times in the past) you’ll need to compare the exact conditions with the published Aircraft Flight Manual (AFM).

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I agree with you, Thank you.

I don’t believe it is what it is actually doing. Instead, it makes concessions because they decided it was better to make FS2020 flying FSX ported aircraft like in FSX so that 3rd party devs could port their add-ons faster to FS2020. It is not dissimilar to what I’m saying about the FS2020 systems and gauges SDK either and probably for the same reasons as well. Given the number of “sophisticated” aircraft available and “ported” from FSX, this begs the question whether this is a good decision from the get go.

Which raises another question to me: in making their normalization algorithm "bending’ their 1000 element model to match the FSX historical flight model behaviour, didn’t they just cut out what could have made their new engine a key differentiator from the past and from competing simulators?

Because it looks to me the main difference between FS2020 and XP11 flight model is this:

  • XP11 extrapolates flight model from a source model. It takes a source model in a certain format (be it 3D, values, both) and derives the model and behaviour from the source. You make the end result matching reality in fine tuning the source data (shape, values etc…).
    .
    The more they refine their equations and physics, the better and closer to reality the flight model.
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    The more they refine their technique, the better the flight model will match any flight situation and physics
    .
    To illustrate what I’m thinking of with this: when they simulate air flow in inverted flight, the model will fly inverted as expected. Or when they simulate the air flow from the props hitting the tail or the elevator, you’ll get expected results from these as well.

  • FS2020 bends the flight model from a target performance. It takes a target behaviour, and a base source model (FSX area type), and integrates the former to match the latter. Extra elements are therefore not building blocks of a refined model, they are a necessity to converge the solution from a few target data point to a few source model data point otherwise their wouldn’t be enough precision to integrating the target performance.
    .
    The more they refine their equations and physics, the closer to target performance the flight model.
    .
    Regardless of the refinement, it won’t make the flight model capable of matching flight situations which are not accounted for in the target performance model.
    .
    To illustrate what I’m thinking of with this: if there are no inverted flight target values, it won’t fly properly inverted. If there is no provision for target values defining the prop wash effect, it won’t be simulated either

I believe therefore both XP11 and FS2020 models are doing the same in the end: matching a target value to a source model. Both are using a source model based on geometry of some sort, but the difference seems to be the target model. XP11 target is real physics and air flow, FS2020 model is expected values:

  • The former is not constrained, the latter depends on the accuracy and number of expected values.

  • The former could produce convincing and acceptable simulations for any flight situations but they could be wrong as a whole, the latter could depart outside its envelop in cases for which there is no matching target to source integration but could be right where it is well defined.

I wouldn’t pretend knowing which one is better than the other, but I can say at least the FS2020 documentation about XP11 is wrong because it doesn’t take in account the latest XP11 developments in the flight model since XP11. It looks in fact as-if the FS2020 SDK docs was redacted by the time they started developing FS2020 and this relates to XP10 area flight model docs (the FS2020 SDK docs about flight model could just be the internal memo they’ve redacted for MSFT when ‘selling’ their approach to the decision maker). And if I’m not mistaken, FS2020 approach is closer to what is used in the industry like in Level D simulators where the flight model is not accurate but is matching expected values for standard flight regimes and situations (it was fun once making barrel rolls in a 737-400 simulator 2 decades ago when all of a sudden the platform was going haywire when 180 deg inverted :wink: )

In the end, I still find XP11 more organic and fluid in the various flight regimes and envelop, whereas I find FS2020 more predictable and synthetic in general.

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I think those have come a long way considering they also have to be used for Upset Prevention Recovery Training (UPRT) nowadays, the motion isn’t of course, that would be something :joy:.

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This is simply not a valid test, at all.

There’s no conclusive observation that can be made by looking at one specific aircraft flight model configuration and then applying that conclusion to the entire flight simulation. How well a particular aircraft meets book values is entirely dependent on how well the flight model author adjusted the values to make the book values possible.

This is exactly the same in both MSFS and X-Plane. X-Plane only uses geometry to the same extent MSFS does, for the most part. All the complex study level flight models developed in XP heavily use datarefs to adjust various tables and scalars to modulate the output of the simulation, because all simulations are imperfect.

If the flight model designer has not input the correct parameters into the model, then you get a crappy simulation, both in MSFS and XP. It’s why the default 172 in XP flies like it has no idea what longitudinal stability is, while payware offerings are much better: that doesn’t mean XPs flight model overall is garbage, just that the configuration of it may be for a given airplane. Similarly, taking the default 787 which doesn’t match book and claiming it means something about the core of the MSFS flight engine is just misguided.

In the right hands, the MSFS modern engine is going to produce some seriously accurate aircraft. How do I know that? Because our Working Title CJ4 does actually hit those book values at all regimes, with correct N1s, fuel flow, climb rates, over various altitudes and ambient pressures. Not only that but we have stall speeds within a knot of two of book, proper approach angles, correct bank rates, etc.

Is the MSFS simulation completely perfect and without limitations or quirks? No, but neither is XPs, by a long shot. These strange questions and tests are apples and parsnips.

-Matt

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I think you misunderstand the OP’s intent. This post seems to be about ego not physics :wink: I applaude your patience!

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I watched the X-plane video and I watched the Dev’s Video’s. I read quite a few of the reply’s and the discussion. You can dismiss anything I have to say if you like or wish too. Because I don’t have anything over a 10th grade level of education. However My father used to make sure the C-130/C-141A and B The C-5A’s built at Lockheed, Where all set to true, along the wings and along the fuselage. by Calibrating the equipment used using a pocket slide rule. What I get out of this whole thing is people are more interested in flying air, doughnuts and coffee, than they are designing and flying airplanes and the aerodynamics. Even when they discuss the flight model, and programing, and never discuss lift surfaces and the fact that no pilots will even touch this conversation blows my mind. What are you really wanting to fly? Mountains, Wind, Weather, Data, doughnuts, peanuts, Or can I not sell anybody the thought of an airplane to go with that? Just saying. Because I do not for one minute believe a real airplane would have looked like the flight in the original video, Nor do I believe that a TBM 960 should do a loop with landing flaps deployed at 120Knots. I wish somebody would get off their ego and get those real pilots in here to find out what the truth is. Because I watched those C-141’s and C-5A’s fly over my head 2 miles from Dobbins Air-force base as a child, back in the late 1960’s! My father wasn’t worried about them falling out of the sky. I find these planes hard to fly in no weather. Some impossible. What am I missing here? Maybe earth is flat after all, and the chem trails? Well no that was people putting particles in the air to design Flight sims. Lets get real and talk about what people really want to fly without having to have a college education on how to design, and program an FMS. Without a 14 hour download every time the programs gets a hickup. As far as XP and MSFS being the grand knowledge kings on flight models, all fail to mention Eagle and DCS taking over and possibly about to end the debate. I would rather just get MSFS2020 up to par, user friendly and soon though. with the option of being a simulator where you just fly the plane, and a game where you have to put in every detail step by step before you get credit in your log book, that got wiped out because you made a stupid mistake, and used developer mode so you could change planes. With out going all the way back out, and working the server just as hard doing that, as it would to just let you switch your airplane on the ground. Enough said. Sorry Guy’s Maybe it should be Plane Simulator.

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That was one very nice and intelligent way to put it, and it shows that when you have a degree of intelligence, other degrees will not match. I could not agree more with Capntedy, nicely puts, salute you, sir

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Thank you for your opinion.

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I didn’t think a simulator should be 100% accurate, but acceptable errors are common even with Aircraft manufacturers, no two aircrafts performances are alike.

2-3% of divergence is common to engineering statistics is very common.
But over 10 times more difference then the common divergence from aircraft specifications.
And how much time does it take to resolve such problems? not much if you ask me.

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Look at this video and tell me if you can demonstrate this kind of performance on FS2020? please.
Thank you.

Multiple answers possible: :upside_down_face:

  • No I can’t because there is no replay system in FS2020! :joy:
  • No I can’t because I would have landed the aircraft much better than this! :smiling_imp:

Kidding aside I agree it doesn’t feel to me like this in FS2020 at all from the few times I’ve dealt with similar conditions.

XP11 always gives me this feeling of organic elements acting on the aircraft and organic response to it (in other words the feeling of being in a fluid), whereas all the Flight Simulator series (FS, P3D) always feel like guided (in other words what you’d probably call “on rails”).

I’m raising the very question of the “1000 elements” flight model for the next Q&A by the way:
Live Dev Q&A: Guided Question - #18 by CptLucky8


edited to highlight the 1st half is only humor.

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With OBS studio you don’t need a reply system. You can record while flying. It doesn’t matter if your landings are not perfect, only to see them on your system it would be wonderful for the improvement of FS2020.

Look at this :

How about watching my other two videos, and tell me what do you think? Maybe you can show me how to get FS2020 give me the experience as in the other two videos. I would be very happy. Thank you.

You can see the other two videos in the previous posts. (just above.)

It is kinda a let down that they praised how good the Sims physics were at launch and everyone’s bubble got popped. I do think it’s a goal they definitely have at the forefront of their minds and it’s consistently worked. For some reason it’s true what others are saying, let’s make it beautiful first. Backwards for simmers, forwards for gamers. They fact that simmers are such a small niche in the overall picture it doesn’t surprise nor even bother me in the least. Just longer for the overall polish that’s all. :blush:

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I think that the developer team really put some physics into the weather, but if they see my videos, they will surly understand how you can give games to play with physics as never before, and make it a real simulator that even REAL simulator developers will be surprised how a game like FS2020 turned out so good.

Thank you for your support.

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Regardless of the physics engine, the planes need to be well done. The feature discovery videos show the engine, but whether the planes themselves are well done is something else. We will truly get an idea of the engine when we get some better aircraft hopefully. I’m sure they’ll keep improving it too

I will say that the turbulence is much better in MSFS (source: student pilot irl) and the taildraggers feel good too (I fly a taildragger irl) or at least good enough for me to not feel a bit difference (I am just a student though)

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