SDK Q&A Stream Feedback

Hello to all,
here is what I think, even if I know I’m going to speak in a vacuum!
I’m wrong, it’s been for a few years now, custom to create games for video consoles and export them to PC, which I think is a simple thing, as computers are and will always be more powerful than a console and accept to work with any computer language unlike consoles. Now that was a good thing, because without consoles, maybe the gaming industry wouldn’t exist today. Now Xbox, has made the challenge to do the opposite. With a commercial purpose behind it of course! Playstation 5! . by buying the license and being able to create the buzz of the first so-called flight simulator on console. The problem is, I think, that they started out with a vision of how it would work on x-box, which is basic like all console games from the arcade!
with primary addons! everything was designed to work on the xbox for the easiest possible future transfer (just launch the game and be on the home interface, it already feels like a video console, you just have to click on the buttons of an xbox controller to navigate). Except that they have been overtaken by events! The world of air simulation is small compared to the world of games, but today, they have done a great job, they have brought together 3 worlds, those coming from FSX, P3D and x-plane with almost unlimited access for the imagination of third parties. All these players and developers have been in this world for a long time, and have a certain requirement.
But you have done a great job to attract many new players and developers. Unfortunately you left and you stayed in the optics of a development of the games compatible for x-box and to want to make that one with these 2 worlds (PC and consoles) but these two worlds will never be compatible, and I hope for my part! that your error is there! by slowing down all the third party developers with your straight line towards x-box, that’s probably why, if I’m not mistaken that PMDG is so long to release their plane, that they are slowed down by too many obstacles directly linked to your operation for an easy transfer to x-box. It’s a pity I think, maybe in a few years, when you finally realize that your true and faithful public will always be there, on PC, you will end up changing and freeing everything to make it easier for developers. This is just my thought, but don’t make the mistake of wanting to mix the two worlds of games, make 2 distinct games, by opening up the game to third parties who will be able to offer us much more content and quality than they could on xbox.
That was my rant of the evening :stuck_out_tongue:
Good evening to all and good flight.
Anyway, great your Q&A it’s a good initiative, but thought of what I had to for them and for us at the end the simeur and future simeur


I was one of the people asking during the end of the stream about if we will see improvements to the flight model in the future.

To be clear, I’m not trying to decrease the value of Asobo’s work and I really think that MSFS is an amazing product with a lot of potential for farther improvements and I’m really excited to see what’s coming next.

Regarding the flight model, an example of that is the incorrect simulation of leading edge lift devices, such as Krueger flaps or slats. They are presently simulated identically as trailing edge flaps when they actually have very different effects on the aerodynamics of the wing. Leading edge flaps will actually not change the lift vs AoA curve but rather increase the stall AoA, allowing to fly at lower speeds by increasing the AoA beyond the clean wing stall AoA, thus delaying the onset of the stall.
Trailing edge flaps will change the camber, shape and surface of the wing and thus increase the lift, changing the lift vs AoA curve by moving it upward on the graph, to put it simply. At the same time, the stall AoA of the wing with the deflected trailing edge flaps will be smaller or equal than the clean wing stall AoA.

Another example that comes to my mind is propeller drag. And I think that there must have been a tremendous misunderstanding between the developers and the community on the subject. As the devs said, there is a propeller drag parameter in the engine config file. But if I understand it correctly, this is the drag of the rotating propeller, when driven by the engine, acting along the propeller blade chord and slowing the propeller’s rotation (prop_cx in the engine config file, propeller section). What the community was talking about, was the drag of the propeller at rest ie not rotating, as what would happen during an engine failure after securing the failed engine. In that case, the propeller, if not feathered, would act as a big speed brake and the aircraft would experience a great amount of drag and glide for a given speed with a higher rate of descent and a more nose down attitude than the same plane with the prop feathered, which is basically the prop orienting its blades into the wind stream to decrease the drag. Tests were made by the community and there is no modelling of this. I have just tested it myself and propellers do not feather at all.

There is also the fact that the CoG changes position along the MAC when changing the sweep angle of the wing in the flight model config file, which shows improper simulation of swept wings which in turn affects the aircraft balance.

I’m just giving these examples at Asobo’s request during the Q&A, but here is a link to a topic which lists some of the most obvious issues at the moment with the flight model.

It has been 15 years since FSX was released and we have now an amazing opportunity for Asobo to fix many of the shortcuts that were taken years ago in the FS flight model.

I have to recognize that the modern flight model with the surface element distribution of the coefficients for the simulation makes it so much easier to design a credible flight model in a few steps and is my opinion a great step forward. However, many third party content producers want the ability to go beyond and bring a higher level of fidelity to their products. That’s why in the past some of them worked with external flight models.

If the MSFS development team were open to address these issues and work with the content producer to make a great flight model for MSFS, then there simply wouldn’t be a need for an external flight model at all!

To conclude, other pilots and I have voiced our comments about the flight model here and as it was mentioned during the stream that the flight model was developed with the help of pilots, then please take our comments into consideration.

About the SDK Q&A sessions, I think it’s a great tool for smaller developers and freeware developers to be kept in the loop of what are the latest developments about the SDK. Some sections are still very empty at the moment. I personally can’t wait to see the new platform that was announced.

Thank you for reading me!


One more issue according to JustFlight developers is the wing dihedral and the rudder behaviour: Flight Model Wing Geometry | Just Flight Community

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Also, Lewis, one of the developers at A2A Simulations has said the following three days ago about MSFS 2020 SDK in response to the SDK issues Aeroplane Heaven devs are having:

Unlike the past versions of MSFS the SDK is not being used by the platform studio to make the aircraft but rather the SDK is being built after the fact. Which any software developer will tell you is always asking for trouble and is arguably the wrong way to go about it. A working example; When game developers advertise a mission editor or model importer in a game as something they used the make the game, you see how this is the ‘correct way’ to do such things and why its so often advertised as a marketing feature of a given Game.

Source: Aeroplane Heaven - Home | Facebook and Redirecting...


It’s all very concerning… And to think what an easy out it would be to simply say “ok, you can make your own external flight model”… And then keep working on the SDK for those developers that just want to make barebone addons.

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That’s what I applaud about MS/Asobo. They really want their flight model to develop and just work correctly.
In the short term this brings some limitations, but in the long term I think it’s the best approach.


There are two problems:

  1. It might take so long that it will be too late.
  2. Asobo seem to be very selective about the developers they discuss with.

Hopefully the new Answers platform will invalidate both points, but it remains to be seen. In my opinion, allowing third part developers to use their own custom flight model while continuing work on the internal flight model is the best of both worlds. What exactly are the downsides?

Well, just my personal interpretation;

  1. Wwe’ll see, but in this endeavor where MS/Asobo have committed to 10 years of support, I don’t think it’ll be an issue. Especially since I’ve seen multiple reports of third party developers stating they’re seeing a steady decline in sales on their Xplane/P3D sales.

  2. As you mentioned yourself, they’re opening it up to non-partnered third party developers. As for your second point here; opening up the flight model to the third party developers will require those developers to invest time/money into creating their own flight model, which would end up excluding the smaller studio’s. Also, if they then make a change to the core flight model, this will most likely require all third party developer to completely reshuffle their custom flight models as well. Bringing even more cost to those third party developers, without additional income streams (they already sold the aircraft, but have to keep interating on their custom models as well as part of the support process).

So as I stated; short term it might look nice (more aircraft released sooner), in the long term it might turn out really bad (smaller studios unable to keep up, more operational costs for the developers left to keep their planes up to date).

I’m pretty sure third party developers will be able to give you much better insight on this, but that’s my (novice) take on it.

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Thanks for the the SDK Q&A! I hope it will come back again next month.

Even if I can’t watch it live during my work hours, I enjoyed watching it afterward.

I am not sure I understood well, but where do we ask our question concerning the SDK or Dev Mode if we can’t attend the live Q&A? I believe in the Q&A it was mentioned that we do this in the 3rd party forum while waiting for AnsweHub to be set?


Hi Jumminvana. Some of the top voted questions were never asked, like this one: SDK Q&A: Guided Question - #7 by gadwin777. Instead, the questions from the chat were asked over this question.

Maybe in the next SDK Q&A, you can allocate the top voted questions to be asked? Because some of us are not available at the time of the SDK Q&A due to our work, time zones, real life commitments, etc. We rely on the voting of questions to be asked if we cannot be there.

As a makeup, can you ask the top voted questions that should have been asked on April 21, at the next SDK Q&A? That would be fair for those of us who posted questions that were highly voted on, but were not asked. If you can do that, that would be appreciated.


No, it wouldn’t require anyone to develop their own flight model. Just like in FSX or P3D, any developer can still use the default flight model if they so choose. And if they do choose to develop their own flight model, that is what they would have done for FSX or P3D and thus it is a normal investiture of time and effort.

Why would it, if a custom flight model bypasses the default model?

Either way, i think i said my piece on the topic. Even though this is an important discussion, i’m not sure this is the place to have it. We’re polluting this Q&A stream feedback with flight model discussion.


Pls answer all questions posted during a Q&A session, not only the ones you pick for answering it during the Q&A. Thx

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Well it seems PMDG as well as QualityWings are progressing well (as they said), so it could be that they are also influencing the flight model as well? Anyway let’s see not forget why did third party developers implemented their own flight model in FSX/P3D, its default flight model is ■■■■ so what is the alternative? Develop your own. Now with MSFS, they have promised to improve on the flight model and I trust them on that because I know for sure other third party developers are pushing them as well. I mean MSFS won’t be the first sim where high fidelity aircrafts use the default flight model, XP for example, (I think) all the third party airliners use the default flight model and never heard of external flight model (maybe it exists but not idea).

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We haven’t heard anything from PMDG about their progress with FS2020 in quite a while. Maybe you’re right, maybe you’re not. We don’t know. I for one am eagerly awaiting an FS2020 update from them.

Whilst i also trust Asobo to improve their flight model, the question really is: how long is that going to take? Can they afford to take that long? I am genuinely wondering if anyone is going to stick around for that long. The people that have stuck with FSX even to this day are the ones who are looking for the most accurate flight models on the market, customers of A2A, PMDG, etc. If companies that pride themselves on the accuracy of their models cannot enter the FS2020 market because of flight model restrictions, that devoted user base will simply not be there.
I am not trying to make a prediction here, because i don’t have enough information. What i am trying to say is that there is a possibility that the user base dries up before Asobo ever manage to develop their flight model to the point where it can be called study level, and they will be forced to abandon it.

X-Plane’s flight model gives much, much better results out of the box than the approach used by FSX, P3D, FS2020. Custom flight models are still better. The thing is that X-Plane is a much more developer friendly platform. Whilst developers usually have to hack their way around P3D to get it to do what they want, X-Plane is built with that kind of access in mind, so no hacking required. With FS2020, however, you can’t even hack your way around limitations. Developers have been given a tiny area in which to play and they’re not allowed to leave it. Is that a good thing or a bad thing in the long run? I don’t know. How many developers find that a fatal limitation? A few, i’m sure.
But my argument is this: Allowing developers as much freedom as possible can only serve to attract more and more users to the platform, and make it more popular. This is the sole reason why FSX is still used to day. This is why Assetto Corsa is still used. Because third party developers took those platforms so much further than they were originally meant to go.

I guess, in the end, only time will tell.

Yes they can? The sim is not even an year old. It took years for pmdg and qw to develop for p3d/fsx. I don’t see a problem here. Even if it is, what other alternative do they have? I don’t see any competition in near future.


I wasn’t talking about PMDG or QW. I was talking about Asobo. I don’t think either of us knows how long will people stick with this sim. Do you think they will continue developing it if only a handful of people are using it? In other words: if it no longer is financially viable?

P3D. X-Plane. Both of which offer what FS2020 currently lacks: developer freedom. Sure, FS2020 has much better graphics and scenery, but is that enough in the long run? I don’t know.

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In my opinion, the way FSX and P3D evolved, from a platform perspective, is not a healthy way forward.

Yes, having an accessible, easy to use, open platform is obviously super important. And developers, like ourselves, drive things forward. But the core question is how it helps the simming community as a whole. The ideal situation is one the enables all simmers to have the same fidelity, all the way from the default 172 to the most premium payware. The simmers themselves are the most important.

If the community of great third parties instead fold feedback into the MSFS teams, who are open to it and actively building the avenues to supply it, then everyone can benefit from their experience and expertise, instead of the knowledge being held only by a select few. Having fragmented islands of totally custom proprietary implementations of everything is the opposite of what is needed for an awesome experience.

I come from an open source background, where those who use a platform also lend their expertise towards enabling others to do what they do on the platform. And so, naturally, my opinion is wouldn’t it be better to make the default flight model unassailably great instead?



I, for one, am convinced that Asobo and MS are fully committed to making all third party aircraft the best they can be, also when it comes to how they handle in the air and on the ground.

From what we hear, they have decided that the best approach toward this goal is to produce an advanced and accurate flight model. A similar attitude has been expressed when it comes to the weather engine. Surely, if they can pull it off, it will make 3rd party designers’ lives easier, at least when building an add-on plane from scratch.

I think we should give Asobo a fair chance to show that they can make this flexible enough before we make it a problem that 3rd party developers cannot replace the flight model entirely.

I find the arguments very strange here.

MSFS has all the technology the other solutions don’t.

I developed for ESP (aka FS98, 2000, 2002, 2004 and FSX) and for XP11.

Did you develop anything for ESP or XP? Can you please explain to me what they have and MSFS lacks in the so called “development freedom” area?

Well, from the last Q&A they said there will be no substituting the flight model for your own.

Two other things off the top of my head is to do with the Marketplace. No guns if you want your plane on there. The other is more affecting us that’s the developer, and that is they have to be subject to DRM so cannot be fully modified. Outside the MP they can do what they want.

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